WO2026007704A1 - Cadre de signalisation de csi et de pmi de communication de dispositif à dispositif en duplex intégral basé sur une mesure et une rétroaction d'ue - Google Patents

Cadre de signalisation de csi et de pmi de communication de dispositif à dispositif en duplex intégral basé sur une mesure et une rétroaction d'ue

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Publication number
WO2026007704A1
WO2026007704A1 PCT/CN2025/101956 CN2025101956W WO2026007704A1 WO 2026007704 A1 WO2026007704 A1 WO 2026007704A1 CN 2025101956 W CN2025101956 W CN 2025101956W WO 2026007704 A1 WO2026007704 A1 WO 2026007704A1
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WO
WIPO (PCT)
Prior art keywords
csi
base station
channel
precoder
frequency band
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
PCT/CN2025/101956
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English (en)
Inventor
Bruno Eugene R. CLERCKX
Mohammed S Aleabe AL-IMARI
Francesc Boixadera-Espax
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
MediaTek Inc
Original Assignee
MediaTek Inc
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Publication date
Application filed by MediaTek Inc filed Critical MediaTek Inc
Publication of WO2026007704A1 publication Critical patent/WO2026007704A1/fr
Pending legal-status Critical Current
Anticipated expiration legal-status Critical

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Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B7/00—Radio transmission systems, i.e. using radiation field
    • H04B7/02—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas
    • H04B7/04—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas
    • H04B7/0413—MIMO systems
    • H04B7/0456—Selection of precoding matrices or codebooks, e.g. using matrices antenna weighting
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B7/00—Radio transmission systems, i.e. using radiation field
    • H04B7/02—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas
    • H04B7/022—Site diversity; Macro-diversity
    • H04B7/026—Co-operative diversity, e.g. using fixed or mobile stations as relays

Definitions

  • the present disclosure relates generally to wireless communications, and more particularly, to techniques of CSI and PMI signaling based on UE measurement and feedback.
  • Wireless communication systems are widely deployed to provide various telecommunication services such as telephony, video, data, messaging, and broadcasts.
  • Typical wireless communication systems may employ multiple-access technologies capable of supporting communication with multiple users by sharing available system resources. Examples of such multiple-access technologies include code division multiple access (CDMA) systems, time division multiple access (TDMA) systems, frequency division multiple access (FDMA) systems, orthogonal frequency division multiple access (OFDMA) systems, single-carrier frequency division multiple access (SC-FDMA) systems, and time division synchronous code division multiple access (TD-SCDMA) systems.
  • CDMA code division multiple access
  • TDMA time division multiple access
  • FDMA frequency division multiple access
  • OFDMA orthogonal frequency division multiple access
  • SC-FDMA single-carrier frequency division multiple access
  • TD-SCDMA time division synchronous code division multiple access
  • 5G New Radio is part of a continuous mobile broadband evolution promulgated by Third Generation Partnership Project (3GPP) to meet new requirements associated with latency, reliability, security, scalability (e.g., with Internet of Things (IoT) ) , and other requirements.
  • 3GPP Third Generation Partnership Project
  • Some aspects of 5G NR may be based on the 4G Long Term Evolution (LTE) standard.
  • LTE Long Term Evolution
  • the apparatus may be a UE.
  • the UE receives a first Channel State Information Reference Signal (CSI-RS) directly from a base station on a first frequency band.
  • the UE receives a second CSI-RS from a collaborative device (CD) on a second frequency band.
  • the second CSI-RS is a frequency-translated version of a CSI-RS transmitted by the base station to the CD on the first frequency band.
  • the UE measures a direct channel (H 2 ) between the base station and the UE based on the first CSI-RS.
  • the UE measures a cascaded channel (H s ⁇ H 1 ) between the base station and the UE through the CD based on the second CSI-RS.
  • H 1 represents a channel from the base station to the CD
  • H s represents a channel from the CD to the UE.
  • the UE generates Channel State Information (CSI) feedback based on the measured direct channel and the measured cascaded channel.
  • the CSI feedback includes at least a first Precoding Matrix Indicator (PMI) for a first precoder (P 1 ) to be applied by the base station for transmission to the CD and a second PMI for a second precoder (P 2 ) to be applied by the base station for direct transmission to the UE.
  • the UE transmits the CSI feedback to the base station.
  • the one or more aspects comprise the features hereinafter fully described and particularly pointed out in the claims.
  • the following description and the annexed drawings set forth in detail certain illustrative features of the one or more aspects. These features are indicative, however, of but a few of the various ways in which the principles of various aspects may be employed, and this description is intended to include all such aspects and their equivalents.
  • FIG. 1 is a diagram illustrating an example of a wireless communications system and an access network.
  • FIG. 2 is a diagram illustrating a base station in communication with a UE in an access network.
  • FIG. 3 illustrates an example logical architecture of a distributed access network.
  • FIG. 4 illustrates an example physical architecture of a distributed access network.
  • FIG. 5 is a diagram showing an example of a DL-centric slot.
  • FIG. 6 is a diagram showing an example of an UL-centric slot.
  • FIG. 7 is a diagram illustrating an example of a full duplex device-to-device communication system.
  • FIG. 8 is a diagram illustrating a full duplex downlink scenario where the gNB performs Rx or Tx on specific frequency resources.
  • FIG. 9 is a diagram illustrating a non-full duplex downlink scenario where the gNB performs Rx or Tx on specific frequency resources.
  • FIG. 10 is a diagram illustrating a non-full duplex uplink scenario where the gNB performs Rx or Tx on specific frequency resources.
  • FIG. 11 is a diagram illustrating a full duplex uplink scenario where the gNB performs Rx or Tx on specific frequency resources.
  • FIG. 12 is a diagram illustrating a downlink full duplex gNB scenario.
  • FIG. 13 is a diagram illustrating a communication system in a downlink full duplex gNB scenario.
  • FIG. 14 is a diagram illustrating a communication process among the gNB, CD and UE, corresponding to Proposal 1.
  • FIG. 15 is a diagram illustrating a communication process among the gNB, CD and UE, corresponding to Proposal 2.
  • FIG. 16 is a diagram illustrating a communication process among the gNB, CD and UE, corresponding to Proposal 3.
  • FIG. 17 is a diagram illustrating the inter-carrier intra-cell CLI.
  • FIG. 18 is a diagram illustrating a communication process among the gNB, CD and UE, corresponding to Proposal 4.
  • FIG. 19 is a diagram illustrating a communication process among the gNB, CD and UE, corresponding to Proposal 5.
  • FIG. 20 is a diagram illustrating a communication process among the gNB, CD and UE, corresponding to Proposal 6.
  • FIG. 21 is a diagram illustrating a downlink non-full duplex gNB scenario.
  • FIG. 22 is a diagram illustrating a communication system in a downlink non-full duplex gNB scenario.
  • FIG. 23 is a diagram illustrating another communication process among the gNB, CD and UE, corresponding to Proposal 1.
  • FIG. 24 is a diagram illustrating another communication process among the gNB, CD and UE, corresponding to Proposal 2.
  • FIG. 25 is a diagram illustrating another communication process among the gNB, CD and UE, corresponding to Proposal 3.
  • FIG. 26 is a diagram illustrating management of inter-carrier intra-cell CLI.
  • FIG. 27 is a diagram illustrating another communication process among the gNB, CD and UE, corresponding to Proposal 4.
  • FIG. 28 is a diagram illustrating another communication process among the gNB, CD and UE, corresponding to Proposal 5.
  • FIG. 29 is a diagram illustrating another communication process among the gNB, CD and UE, corresponding to Proposal 6.
  • FIG. 30 is a diagram illustrating management of inter-carrier intra-cell CLI.
  • FIG. 31 is a diagram illustrating another communication process among the gNB, CD and UE, corresponding to Proposal 7.
  • FIG. 32 illustrates a flow chart of a first example of a process for CSI and PMI signaling based on UE measurement and feedback.
  • FIG. 33 illustrates a flow chart of a second example of a process for CSI and PMI signaling based on UE measurement and feedback.
  • FIG. 34 illustrates a flow chart of a third example of a process for CSI and PMI signaling based on UE measurement and feedback.
  • FIG. 35 illustrates a flow chart of a fourth example of a process for CSI and PMI signaling based on UE measurement and feedback.
  • processors include microprocessors, microcontrollers, graphics processing units (GPUs) , central processing units (CPUs) , application processors, digital signal processors (DSPs) , reduced instruction set computing (RISC) processors, systems on a chip (SoC) , baseband processors, field programmable gate arrays (FPGAs) , programmable logic devices (PLDs) , state machines, gated logic, discrete hardware circuits, and other suitable hardware configured to perform the various functionality described throughout this disclosure.
  • processors in the processing system may execute software.
  • Software shall be construed broadly to mean instructions, instruction sets, code, code segments, program code, programs, subprograms, software components, applications, software applications, software packages, routines, subroutines, objects, executables, threads of execution, procedures, functions, etc., whether referred to as software, firmware, middleware, microcode, hardware description language, or otherwise.
  • the functions described may be implemented in hardware, software, or any combination thereof. If implemented in software, the functions may be stored on or encoded as one or more instructions or code on a computer-readable medium.
  • Computer-readable media includes computer storage media. Storage media may be any available media that can be accessed by a computer.
  • such computer-readable media can comprise a random-access memory (RAM) , a read-only memory (ROM) , an electrically erasable programmable ROM (EEPROM) , optical disk storage, magnetic disk storage, other magnetic storage devices, combinations of the aforementioned types of computer-readable media, or any other medium that can be used to store computer executable code in the form of instructions or data structures that can be accessed by a computer.
  • RAM random-access memory
  • ROM read-only memory
  • EEPROM electrically erasable programmable ROM
  • optical disk storage magnetic disk storage
  • magnetic disk storage other magnetic storage devices
  • combinations of the aforementioned types of computer-readable media or any other medium that can be used to store computer executable code in the form of instructions or data structures that can be accessed by a computer.
  • FIG. 1 is a diagram illustrating an example of a wireless communications system and an access network 100.
  • the wireless communications system (also referred to as a wireless wide area network (WWAN) ) includes base stations 102, UEs 104, an Evolved Packet Core (EPC) 160, and another core network 190 (e.g., a 5G Core (5GC) ) .
  • the base stations 102 may include macrocells (high power cellular base station) and/or small cells (low power cellular base station) .
  • the macrocells include base stations.
  • the small cells include femtocells, picocells, and microcells.
  • the base stations 102 configured for 4G LTE may interface with the EPC 160 through backhaul links 132 (e.g., SI interface) .
  • the base stations 102 configured for 5G NR may interface with core network 190 through backhaul links 184.
  • NG-RAN Next Generation RAN
  • the base stations 102 may perform one or more of the following functions: transfer of user data, radio channel ciphering and deciphering, integrity protection, header compression, mobility control functions (e.g., handover, dual connectivity) , inter cell interference coordination, connection setup and release, load balancing, distribution for non-access stratum (NAS) messages, NAS node selection, synchronization, radio access network (RAN) sharing, multimedia broadcast multicast service (MBMS) , subscriber and equipment trace, RAN information management (RIM) , paging, positioning, and delivery of warning messages.
  • NAS non-access stratum
  • RAN radio access network
  • MBMS multimedia broadcast multicast service
  • RIM RAN information management
  • the base stations 102 may communicate directly or indirectly (e.g., through the EPC 160 or core network 190) with each other over backhaul links 134 (e.g., X2 interface) .
  • the backhaul links 134 may be wired or wireless.
  • the base stations 102 may wirelessly communicate with the UEs 104. Each of the base stations 102 may provide communication coverage for a respective geographic coverage area 110. There may be overlapping geographic coverage areas 110. For example, the small cell 102’ may have a coverage area 110’ that overlaps the coverage area 110 of one or more macro base stations 102.
  • a network that includes both small cell and macrocells may be known as a heterogeneous network.
  • a heterogeneous network may also include Home Evolved Node Bs (eNBs) (HeNBs) , which may provide service to a restricted group known as a closed subscriber group (CSG) .
  • eNBs Home Evolved Node Bs
  • HeNBs Home Evolved Node Bs
  • CSG closed subscriber group
  • the communication links 120 between the base stations 102 and the UEs 104 may include uplink (UL) (also referred to as reverse link) transmissions from a UE 104 to a base station 102 and/or downlink (DL) (also referred to as forward link) transmissions from a base station 102 to a UE 104.
  • the communication links 120 may use multiple-input and multiple-output (MIMO) antenna technology, including spatial multiplexing, beamforming, and/or transmit diversity.
  • the communication links may be through one or more carriers.
  • the base stations 102/UEs 104 may use spectrum up to 7 MHz (e.g., 5, 10, 15, 20, 100, 400, etc.
  • the component carriers may include a primary component carrier and one or more secondary component carriers.
  • a primary component carrier may be referred to as a primary cell (PCell) and a secondary component carrier may be referred to as a secondary cell (SCell) .
  • D2D communication link 158 may use the DL/UL WWAN spectrum.
  • the D2D communication link 158 may use one or more sidelink channels, such as a physical sidelink broadcast channel (PSBCH) , a physical sidelink discovery channel (PSDCH) , a physical sidelink shared channel (PSSCH) , and a physical sidelink control channel (PSCCH) .
  • sidelink channels such as a physical sidelink broadcast channel (PSBCH) , a physical sidelink discovery channel (PSDCH) , a physical sidelink shared channel (PSSCH) , and a physical sidelink control channel (PSCCH) .
  • sidelink channels such as a physical sidelink broadcast channel (PSBCH) , a physical sidelink discovery channel (PSDCH) , a physical sidelink shared channel (PSSCH) , and a physical sidelink control channel (PSCCH) .
  • D2D communication may be through a variety of wireless D2D communications systems, such as for example, FlashLinQ, WiMedia,
  • the wireless communications system may further include a Wi-Fi access point (AP) 150 in communication with Wi-Fi stations (STAs) 152 via communication links 154 in a 5 GHz unlicensed frequency spectrum.
  • AP Wi-Fi access point
  • STAs Wi-Fi stations
  • communication links 154 in a 5 GHz unlicensed frequency spectrum.
  • the STAs 152/AP 150 may perform a clear channel assessment (CCA) prior to communicating in order to determine whether the channel is available.
  • CCA clear channel assessment
  • the small cell 102’ may operate in a licensed and/or an unlicensed frequency spectrum. When operating in an unlicensed frequency spectrum, the small cell 102’ may employ NR and use the same 5 GHz unlicensed frequency spectrum as used by the Wi-Fi AP 150. The small cell 102’ , employing NR in an unlicensed frequency spectrum, may boost coverage to and/or increase capacity of the access network.
  • a base station 102 may include an eNB, gNodeB (gNB) , or another type of base station.
  • Some base stations, such as gNB 180 may operate in a traditional sub 6 GHz spectrum, in millimeter wave (mmW) frequencies, and/or near mmW frequencies in communication with the UE 104.
  • mmW millimeter wave
  • mmW millimeter wave
  • mmW base station Extremely high frequency (EHF) is part of the RF in the electromagnetic spectrum. EHF has a range of 30 GHz to 300 GHz and a wavelength between 1 millimeter and 10 millimeters.
  • Radio waves in the band may be referred to as a millimeter wave.
  • Near mmW may extend down to a frequency of 3 GHz with a wavelength of 100 millimeters.
  • the super high frequency (SHF) band extends between 3 GHz and 30 GHz, also referred to as centimeter wave.
  • Communications using the mmW/near mmW radio frequency band (e.g., 3 GHz -300 GHz) has extremely high path loss and a short range.
  • the mmW base station 180 may utilize beamforming 182 with the UE 104 to compensate for the extremely high path loss and short range.
  • the base station 180 may transmit a beamformed signal to the UE 104 in one or more transmit directions 108a.
  • the UE 104 may receive the beamformed signal from the base station 180 in one or more receive directions 108b.
  • the UE 104 may also transmit a beamformed signal to the base station 180 in one or more transmit directions.
  • the base station 180 may receive the beamformed signal from the UE 104 in one or more receive directions.
  • the base station 180/UE 104 may perform beam training to determine the best receive and transmit directions for each of the base station 180/UE 104.
  • the transmit and receive directions for the base station 180 may or may not be the same.
  • the transmit and receive directions for the UE 104 may or may not be the same.
  • the EPC 160 may include a Mobility Management Entity (MME) 162, other MMEs 164, a Serving Gateway 166, a Multimedia Broadcast Multicast Service (MBMS) Gateway 168, a Broadcast Multicast Service Center (BM-SC) 170, and a Packet Data Network (PDN) Gateway 172.
  • MME Mobility Management Entity
  • MBMS Multimedia Broadcast Multicast Service
  • BM-SC Broadcast Multicast Service Center
  • PDN Packet Data Network
  • the MME 162 may be in communication with a Home Subscriber Server (HSS) 174.
  • HSS Home Subscriber Server
  • the MME 162 is the control node that processes the signaling between the UEs 104 and the EPC 160.
  • the MME 162 provides bearer and connection management. All user Internet protocol (IP) packets are transferred through the Serving Gateway 166, which itself is connected to the PDN Gateway 172.
  • IP Internet protocol
  • the PDN Gateway 172 provides UE IP address allocation as well as other functions.
  • the PDN Gateway 172 and the BM-SC 170 are connected to the IP Services 176.
  • the IP Services 176 may include the Internet, an intranet, an IP Multimedia Subsystem (IMS) , a PS Streaming Service, and/or other IP services.
  • the BM-SC 170 may provide functions for MBMS user service provisioning and delivery.
  • the BM-SC 170 may serve as an entry point for content provider MBMS transmission, may be used to authorize and initiate MBMS Bearer Services within a public land mobile network (PLMN) , and may be used to schedule MBMS transmissions.
  • PLMN public land mobile network
  • the MBMS Gateway 168 may be used to distribute MBMS traffic to the base stations 102 belonging to a Multicast Broadcast Single Frequency Network (MBSFN) area broadcasting a particular service, and may be responsible for session management (start/stop) and for collecting eMBMS related charging information.
  • MMSFN Multicast Broadcast Single Frequency Network
  • the core network 190 may include a Access and Mobility Management Function (AMF) 192, other AMFs 193, a location management function (LMF) 198, a Session Management Function (SMF) 194, and a User Plane Function (UPF) 195.
  • the AMF 192 may be in communication with a Unified Data Management (UDM) 196.
  • the AMF 192 is the control node that processes the signaling between the UEs 104 and the core network 190.
  • the SMF 194 provides QoS flow and session management. All user Internet protocol (IP) packets are transferred through the UPF 195.
  • the UPF 195 provides UE IP address allocation as well as other functions.
  • the UPF 195 is connected to the IP Services 197.
  • the IP Services 197 may include the Internet, an intranet, an IP Multimedia Subsystem (IMS) , a PS Streaming Service, and/or other IP services.
  • IMS IP Multimedia Subsystem
  • the base station may also be referred to as a gNB, Node B, evolved Node B (eNB) , an access point, a base transceiver station, a radio base station, a radio transceiver, a transceiver function, a basic service set (BSS) , an extended service set (ESS) , a transmit reception point (TRP) , or some other suitable terminology.
  • the base station 102 provides an access point to the EPC 160 or core network 190 for a UE 104.
  • Examples of UEs 104 include a cellular phone, a smart phone, a session initiation protocol (SIP) phone, a laptop, a personal digital assistant (PDA) , a satellite radio, a global positioning system, a multimedia device, a video device, a digital audio player (e.g., MP3 player) , a camera, a game console, a tablet, a smart device, a wearable device, a vehicle, an electric meter, a gas pump, a large or small kitchen appliance, a healthcare device, an implant, a sensor/actuator, a display, or any other similar functioning device.
  • SIP session initiation protocol
  • PDA personal digital assistant
  • the UEs 104 may be referred to as IoT devices (e.g., parking meter, gas pump, toaster, vehicles, heart monitor, etc. ) .
  • the UE 104 may also be referred to as a station, a mobile station, a subscriber station, a mobile unit, a subscriber unit, a wireless unit, a remote unit, a mobile device, a wireless device, a wireless communications device, a remote device, a mobile subscriber station, an access terminal, a mobile terminal, a wireless terminal, a remote terminal, a handset, a user agent, a mobile client, a client, or some other suitable terminology.
  • NR 5G New Radio
  • LTE Long Term Evolution
  • LTE-A LTE-Advanced
  • CDMA Code Division Multiple Access
  • GSM Global System for Mobile communications
  • FIG. 2 is a block diagram of a base station 210 in communication with a UE 250 in an access network.
  • IP packets from the EPC 160 may be provided to a controller/processor 275.
  • the controller/processor 275 implements layer 3 and layer 2 functionality.
  • Layer 3 includes a radio resource control (RRC) layer
  • layer 2 includes a packet data convergence protocol (PDCP) layer, a radio link control (RLC) layer, and a medium access control (MAC) layer.
  • RRC radio resource control
  • PDCP packet data convergence protocol
  • RLC radio link control
  • MAC medium access control
  • the controller/processor 275 provides RRC layer functionality associated with broadcasting of system information (e.g., MIB, SIBs) , RRC connection control (e.g., RRC connection paging, RRC connection establishment, RRC connection modification, and RRC connection release) , inter radio access technology (RAT) mobility, and measurement configuration for UE measurement reporting; PDCP layer functionality associated with header compression /decompression, security (ciphering, deciphering, integrity protection, integrity verification) , and handover support functions; RLC layer functionality associated with the transfer of upper layer packet data units (PDUs) , error correction through ARQ, concatenation, segmentation, and reassembly of RLC service data units (SDUs) , re-segmentation of RLC data PDUs, and reordering of RLC data PDUs; and MAC layer functionality associated with mapping between logical channels and transport channels, multiplexing of MAC SDUs onto transport blocks (TBs) , demultiplexing of MAC SDU
  • the transmit (TX) processor 216 and the receive (RX) processor 270 implement layer 1 functionality associated with various signal processing functions.
  • Layer 1 which includes a physical (PHY) layer, may include error detection on the transport channels, forward error correction (FEC) coding/decoding of the transport channels, interleaving, rate matching, mapping onto physical channels, modulation/demodulation of physical channels, and MIMO antenna processing.
  • the TX processor 216 handles mapping to signal constellations based on various modulation schemes (e.g., binary phase-shift keying (BPSK) , quadrature phase-shift keying (QPSK) , M-phase-shift keying (M-PSK) , M-quadrature amplitude modulation (M-QAM) ) .
  • BPSK binary phase-shift keying
  • QPSK quadrature phase-shift keying
  • M-PSK M-phase-shift keying
  • M-QAM M-quadrature amplitude modulation
  • the coded and modulated symbols may then be split into parallel streams.
  • Each stream may then be mapped to an OFDM subcarrier, multiplexed with a reference signal (e.g., pilot) in the time and/or frequency domain, and then combined together using an Inverse Fast Fourier Transform (IFFT) to produce a physical channel carrying a time domain OFDM symbol stream.
  • IFFT Inverse Fast Fourier Transform
  • the OFDM stream is spatially precoded to produce multiple spatial streams.
  • Channel estimates from a channel estimator 274 may be used to determine the coding and modulation scheme, as well as for spatial processing.
  • the channel estimate may be derived from a reference signal and/or channel condition feedback transmitted by the UE 250.
  • Each spatial stream may then be provided to a different antenna 220 via a separate transmitter 218TX.
  • Each transmitter 218TX may modulate an RF carrier with a respective spatial stream for transmission.
  • each receiver 254RX receives a signal through its respective antenna 252.
  • Each receiver 254RX recovers information modulated onto an RF carrier and provides the information to the receive (RX) processor 256.
  • the TX processor 268 and the RX processor 256 implement layer 1 functionality associated with various signal processing functions.
  • the RX processor 256 may perform spatial processing on the information to recover any spatial streams destined for the UE 250. If multiple spatial streams are destined for the UE 250, they may be combined by the RX processor 256 into a single OFDM symbol stream.
  • the RX processor 256 then converts the OFDM symbol stream from the time-domain to the frequency domain using a Fast Fourier Transform (FFT) .
  • FFT Fast Fourier Transform
  • the frequency domain signal comprises a separate OFDM symbol stream for each subcarrier of the OFDM signal.
  • the symbols on each subcarrier, and the reference signal are recovered and demodulated by determining the most likely signal constellation points transmitted by the base station 210. These soft decisions may be based on channel estimates computed by the channel estimator 258.
  • the soft decisions are then decoded and deinterleaved to recover the data and control signals that were originally transmitted by the base station 210 on the physical channel.
  • the data and control signals are then provided to the controller/processor 259, which implements layer 3 and layer 2 functionality.
  • the controller/processor 259 can be associated with a memory 260 that stores program codes and data.
  • the memory 260 may be referred to as a computer-readable medium.
  • the controller/processor 259 provides demultiplexing between transport and logical channels, packet reassembly, deciphering, header decompression, and control signal processing to recover IP packets from the EPC 160.
  • the controller/processor 259 is also responsible for error detection using an ACK and/or NACK protocol to support HARQ operations.
  • the controller/processor 259 provides RRC layer functionality associated with system information (e.g., MIB, SIBs) acquisition, RRC connections, and measurement reporting; PDCP layer functionality associated with header compression /decompression, and security (ciphering, deciphering, integrity protection, integrity verification) ; RLC layer functionality associated with the transfer of upper layer PDUs, error correction through ARQ, concatenation, segmentation, and reassembly of RLC SDUs, re-segmentation of RLC data PDUs, and reordering of RLC data PDUs; and MAC layer functionality associated with mapping between logical channels and transport channels, multiplexing of MAC SDUs onto TBs, demultiplexing of MAC SDUs from TBs, scheduling information reporting, error correction through HARQ, priority handling, and logical channel prioritization.
  • RRC layer functionality associated with system information (e.g., MIB, SIBs) acquisition, RRC connections, and measurement reporting
  • PDCP layer functionality associated with
  • Channel estimates derived by a channel estimator 258 from a reference signal or feedback transmitted by the base station 210 may be used by the TX processor 268 to select the appropriate coding and modulation schemes, and to facilitate spatial processing.
  • the spatial streams generated by the TX processor 268 may be provided to different antenna 252 via separate transmitters 254TX. Each transmitter 254TX may modulate an RF carrier with a respective spatial stream for transmission.
  • the UL transmission is processed at the base station 210 in a manner similar to that described in connection with the receiver function at the UE 250.
  • Each receiver 218RX receives a signal through its respective antenna 220.
  • Each receiver 218RX recovers information modulated onto an RF carrier and provides the information to a RX processor 270.
  • the controller/processor 275 can be associated with a memory 276 that stores program codes and data.
  • the memory 276 may be referred to as a computer-readable medium.
  • the controller/processor 275 provides demultiplexing between transport and logical channels, packet reassembly, deciphering, header decompression, control signal processing to recover IP packets from the UE 250. IP packets from the controller/processor 275 may be provided to the EPC 160.
  • the controller/processor 275 is also responsible for error detection using an ACK and/or NACK protocol to support HARQ operations.
  • New radio may refer to radios configured to operate according to a new air interface (e.g., other than Orthogonal Frequency Divisional Multiple Access (OFDMA) -based air interfaces) or fixed transport layer (e.g., other than Internet Protocol (IP) ) .
  • NR may utilize OFDM with a cyclic prefix (CP) on the uplink and downlink and may include support for half-duplex operation using time division duplexing (TDD) .
  • NR may include Enhanced Mobile Broadband (eMBB) service targeting wide bandwidth (e.g. 80 MHz beyond) , millimeter wave (mmW) targeting high carrier frequency (e.g. 60 GHz) , massive MTC (mMTC) targeting non-backward compatible MTC techniques, and/or mission critical targeting ultra-reliable low latency communications (URLLC) service.
  • eMBB Enhanced Mobile Broadband
  • mmW millimeter wave
  • mMTC massive MTC
  • URLLC ultra-reliable low latency communications
  • NR resource blocks may span 12 sub-carriers with a sub-carrier bandwidth of 60 kHz over a 0.25 ms duration or a bandwidth of 30 kHz over a 0.5 ms duration (similarly, 50MHz BW for 15kHz SCS over a 1 ms duration) .
  • Each radio frame may consist of 10 subframes (10, 20, 40 or 80 NR slots) with a length of 10 ms.
  • Each slot may indicate a link direction (i.e., DL or UL) for data transmission and the link direction for each slot may be dynamically switched.
  • Each slot may include DL/UL data as well as DL/UL control data.
  • UL and DL slots for NR may be as described in more detail below with respect to FIGs. 5 and 6.
  • the NR RAN may include a central unit (CU) and distributed units (DUs) .
  • a NR BS e.g., gNB, 5G Node B, Node B, transmission reception point (TRP) , access point (AP)
  • NR cells can be configured as access cells (ACells) or data only cells (DCells) .
  • the RAN e.g., a central unit or distributed unit
  • DCells may be cells used for carrier aggregation or dual connectivity and may not be used for initial access, cell selection/reselection, or handover.
  • DCells may not transmit synchronization signals (SS) in some cases DCells may transmit SS.
  • SS synchronization signals
  • NR BSs may transmit downlink signals to UEs indicating the cell type. Based on the cell type indication, the UE may communicate with the NR BS. For example, the UE may determine NR BSs to consider for cell selection, access, handover, and/or measurement based on the indicated cell type.
  • FIG. 3 illustrates an example logical architecture of a distributed RAN 300, according to aspects of the present disclosure.
  • a 5G access node 306 may include an access node controller (ANC) 302.
  • the ANC may be a central unit (CU) of the distributed RAN.
  • the backhaul interface to the next generation core network (NG-CN) 304 may terminate at the ANC.
  • the backhaul interface to neighboring next generation access nodes (NG-ANs) 310 may terminate at the ANC.
  • the ANC may include one or more TRPs 308 (which may also be referred to as BSs, NR BSs, Node Bs, 5G NBs, APs, or some other term) .
  • TRPs 308 which may also be referred to as BSs, NR BSs, Node Bs, 5G NBs, APs, or some other term.
  • TRP may be used interchangeably with “cell. ”
  • the TRPs 308 may be a distributed unit (DU) .
  • the TRPs may be connected to one ANC (ANC 302) or more than one ANC (not illustrated) .
  • ANC 302 ANC 302
  • RaaS radio as a service
  • a TRP may include one or more antenna ports.
  • the TRPs may be configured to individually (e.g., dynamic selection) or jointly (e.g., joint transmission) serve traffic to a UE.
  • the local architecture of the distributed RAN 300 may be used to illustrate fronthaul definition.
  • the architecture may be defined that support fronthauling solutions across different deployment types.
  • the architecture may be based on transmit network capabilities (e.g., bandwidth, latency, and/or jitter) .
  • the architecture may share features and/or components with LTE.
  • the next generation AN (NG-AN) 310 may support dual connectivity with NR.
  • the NG-AN may share a common fronthaul for LTE and NR.
  • the architecture may enable cooperation between and among TRPs 308. For example, cooperation may be preset within a TRP and/or across TRPs via the ANC 302. According to aspects, no inter-TRP interface may be needed/present.
  • a dynamic configuration of split logical functions may be present within the architecture of the distributed RAN 300.
  • the PDCP, RLC, MAC protocol may be adaptably placed at the ANC or TRP.
  • FIG. 4 illustrates an example physical architecture of a distributed RAN 400, according to aspects of the present disclosure.
  • a centralized core network unit (C-CU) 402 may host core network functions.
  • the C-CU may be centrally deployed.
  • C-CU functionality may be offloaded (e.g., to advanced wireless services (AWS) ) , in an effort to handle peak capacity.
  • a centralized RAN unit (C-RU) 404 may host one or more ANC functions.
  • the C-RU may host core network functions locally.
  • the C-RU may have distributed deployment.
  • the C-RU may be closer to the network edge.
  • a distributed unit (DU) 406 may host one or more TRPs.
  • the DU may be located at edges of the network with radio frequency (RF) functionality.
  • RF radio frequency
  • FIG. 5 is a diagram 500 showing an example of a DL-centric slot.
  • the DL-centric slot may include a control portion 502.
  • the control portion 502 may exist in the initial or beginning portion of the DL-centric slot.
  • the control portion 502 may include various scheduling information and/or control information corresponding to various portions of the DL-centric slot.
  • the control portion 502 may be a physical DL control channel (PDCCH) , as indicated in FIG. 5.
  • the DL-centric slot may also include a DL data portion 504.
  • the DL data portion 504 may sometimes be referred to as the payload of the DL-centric slot.
  • the DL data portion 504 may include the communication resources utilized to communicate DL data from the scheduling entity (e.g., UE or BS) to the subordinate entity (e.g., UE) .
  • the DL data portion 504 may be a physical DL shared channel (PDSCH) .
  • PDSCH physical DL shared channel
  • the DL-centric slot may also include a common UL portion 506.
  • the common UL portion 506 may sometimes be referred to as an UL burst, a common UL burst, and/or various other suitable terms.
  • the common UL portion 506 may include feedback information corresponding to various other portions of the DL-centric slot.
  • the common UL portion 506 may include feedback information corresponding to the control portion 502.
  • Non-limiting examples of feedback information may include an ACK signal, a NACK signal, a HARQ indicator, and/or various other suitable types of information.
  • the common UL portion 506 may include additional or alternative information, such as information pertaining to random access channel (RACH) procedures, scheduling requests (SRs) , and various other suitable types of information.
  • RACH random access channel
  • SRs scheduling requests
  • the end of the DL data portion 504 may be separated in time from the beginning of the common UL portion 506.
  • This time separation may sometimes be referred to as a gap, a guard period, a guard interval, and/or various other suitable terms.
  • This separation provides time for the switch-over from DL communication (e.g., reception operation by the subordinate entity (e.g., UE) ) to UL communication (e.g., transmission by the subordinate entity (e.g., UE)) .
  • DL communication e.g., reception operation by the subordinate entity (e.g., UE)
  • UL communication e.g., transmission by the subordinate entity (e.g., UE)
  • FIG. 6 is a diagram 600 showing an example of an UL-centric slot.
  • the UL-centric slot may include a control portion 602.
  • the control portion 602 may exist in the initial or beginning portion of the UL-centric slot.
  • the control portion 602 in FIG. 6 may be similar to the control portion 502 described above with reference to FIG. 5.
  • the UL-centric slot may also include an UL data portion 604.
  • the UL data portion 604 may sometimes be referred to as the pay load of the UL-centric slot.
  • the UL portion may refer to the communication resources utilized to communicate UL data from the subordinate entity (e.g., UE) to the scheduling entity (e.g., UE or BS) .
  • the control portion 602 may be a physical DL control channel (PDCCH) .
  • PDCCH physical DL control channel
  • the end of the control portion 602 may be separated in time from the beginning of the UL data portion 604. This time separation may sometimes be referred to as a gap, guard period, guard interval, and/or various other suitable terms. This separation provides time for the switch-over from DL communication (e.g., reception operation by the scheduling entity) to UL communication (e.g., transmission by the scheduling entity) .
  • the UL-centric slot may also include a common UL portion 606.
  • the common UL portion 606 in FIG. 6 may be similar to the common UL portion 506 described above with reference to FIG. 5.
  • the common UL portion 606 may additionally or alternatively include information pertaining to channel quality indicator (CQI) , sounding reference signals (SRSs) , and various other suitable types of information.
  • CQI channel quality indicator
  • SRSs sounding reference signals
  • One of ordinary skill in the art will understand that the foregoing is merely one example of an UL-centric slot and alternative structures having similar features may exist without necessarily deviating from the aspects described herein.
  • two or more subordinate entities may communicate with each other using sidelink signals.
  • Real-world applications of such sidelink communications may include public safety, proximity services, UE-to-network relaying, vehicle-to-vehicle (V2V) communications, Internet of Everything (IoE) communications, IoT communications, mission-critical mesh, and/or various other suitable applications.
  • a sidelink signal may refer to a signal communicated from one subordinate entity (e.g., UE1) to another subordinate entity (e.g., UE2) without relaying that communication through the scheduling entity (e.g., UE or BS) , even though the scheduling entity may be utilized for scheduling and/or control purposes.
  • the sidelink signals may be communicated using a licensed spectrum (unlike wireless local area networks, which typically use an unlicensed spectrum) .
  • MIMO Multiple-Input Multiple-Output
  • full duplex collaborative devices may be incorporated to enable intra-band multicarrier operation, where different carriers within the same frequency band can be used simultaneously.
  • Band #1 is deployed in low-band or mid-band spectrum (e.g., 2.5 GHz or 3.5 GHz) to provide wide-area coverage for gNodeBs (gNBs)
  • Band #2 is deployed in higher mid-band frequencies (e.g., 4.7 GHz or 6 GHz) to provide limited geographical coverage.
  • Full duplex collaborative devices are essential for this operation.
  • FIG. 7 is a diagram 700 illustrating an example of a full duplex device-to-device communication system. It illustrates the cooperative MIMO or cooperative communications among the gNB, the user equipment (UE) , and the collaborative device (CD) .
  • the gNB is deployed to serve the UE, such as smart glasses or similar low-capability devices.
  • the system further incorporates the CD with enhanced operational capabilities compared to the UE.
  • the CD can assist in the transmission of data between the gNB and the UE, thereby improving downlink or uplink performance.
  • the gNB may transmit multiple signal streams, one directed toward the UE and another toward the CD. Since both streams carry data intended for the UE, upon receiving its designated stream, the CD performs an amplify-and-forward (A&F) operation with frequency translation, converting the signal from a first frequency band (e.g., Band #1) to a second frequency band (e.g., Band #2) , and subsequently relays the processed signal to the UE. Consequently, the UE receives two distinct signal streams: one directly from the gNB on Band #1 and the other through the CD on Band #2.
  • A&F amplify-and-forward
  • This cooperative transmission mechanism effectively enhances the spatial or MIMO dimensions compared to a non-cooperative scenario where the UE connects solely to the gNB.
  • the gNB may transmit a single MIMO stream or layer to the UE.
  • the system enables the utilization of multiple transmission layers (e.g., two layers) .
  • the full duplex capability of the CD is used for enabling simultaneous reception on Band #1 and transmission on Band #2, effectively implementing intra-band multicarrier operation. Without full duplex functionality at the CD, the system would be unable to maintain continuous data flow from the gNB to the UE through both direct and relay paths simultaneously. This full duplex operation at the CD must maintain strict latency constraints, specifically keeping the processing delay below the cyclic prefix duration to ensure proper signal reception at the UE.
  • the amplify-and-forward operation performed by the CD involves receiving the signal on Band #1, performing necessary signal processing including frequency translation to Band #2, and forwarding the signal to the UE.
  • This operation differs from decode-and-forward approaches as the CD does not decode the data to the bit level but rather processes the signal at the symbol level, enabling lower latency operation.
  • the frequency translation between Band #1 and Band #2 enables the UE to receive multiple MIMO streams despite its limited antenna capabilities, as the streams arrive on orthogonal frequency resources rather than requiring spatial separation.
  • FIG. 8 is a diagram 800 illustrating a full duplex downlink scenario where the gNB performs reception (Rx) or transmission (Tx) on specific frequency resources.
  • FIG. 9 is a diagram 900 illustrating a non-full duplex downlink scenario where the gNB performs Rx or Tx on specific frequency resources.
  • FIG. 10 is a diagram 1000 illustrating a non-full duplex uplink scenario where the gNB performs Rx or Tx on specific frequency resources.
  • FIG. 11 is a diagram 1100 illustrating a full duplex uplink scenario where the gNB performs Rx or Tx on specific frequency resources.
  • each frequency resource may be divided into multiple frequency bands (sometimes simply called frequency resources in this disclosure) .
  • each frequency resource may include an upper part (also called the blue band or blue resource in this disclosure) , a middle part (also called the orange band or orange resource in this disclosure) , and a lower part.
  • the gNB performs Rx or Tx on orange resources.
  • the gNB may transmit two data streams, denoted as W1 and W2, utilizing distinct frequency segments, which may correspond to different carriers or different sub-bands within the same carrier, referred to as Band #1 and Band #2 respectively.
  • W2 is transmitted directly to the UE on Band #1
  • W1 is directed to the CD on Band #1 that subsequently performs frequency translation from Band #1 to Band #2 before relaying the signal to the UE.
  • This cooperative transmission scheme introduces potential interference, including co-channel interference (CCI) arising within the same frequency band and CLI arising between different frequency bands.
  • CCI co-channel interference
  • the gNB When the gNB possesses full duplex capability, it can simultaneously transmit on one frequency band while receiving on another frequency band. Conversely, when the gNB lacks full duplex capability, it is restricted to either transmitting or receiving at any given time.
  • the gNB is configured to receive transmissions from other UEs (e.g., UE’ ) on Band #2
  • the concurrent relay transmission from the CD to the target UE may cause interference (i.e., the CCI) to the gNB.
  • interference i.e., the CCI
  • signal leakage from this CD transmission on Band #2 to Band #1 may adversely affect the UE (i.e., the CLI) .
  • the UE receives its desired signal from the CD in Band #2, such leakage may potentially degrade the reception quality of signals transmitted from the gNB in Band #1.
  • additional interference may arise from an external UE (e.g., the UE’) operating outside the personal network.
  • the external UE transmits to the gNB
  • its uplink transmission may cause interference (i.e., the CLI) to the downlink reception of the target UE within the personal network.
  • interference i.e., the CLI
  • another set of interference conditions may occur between the gNB's transmission and other concurrent network operations.
  • the primary technical objective focuses on optimizing transmission from the gNB to both the UE and the CD, with the ultimate destination being the UE. That is, the CD serves solely as an intermediary relay node. Concurrently, the system introduces interference reduction mechanisms, primarily focusing on the minimization of CLI and CCI.
  • the technical challenges of intra-band multicarrier operation include design and report of precoders and Channel State Information (CSI) , CLI, and CCI measurements, and management of both inter-carrier and intra-carrier CLI. These involve tailored design of combined CSI signaling, robust CLI receiver, CLI detection and reporting, and Precoding Matrix Indicator (PMI) recommendation mechanism, all of which are based on Channel State Information Reference Signal (CSI-RS) measurement and feedback in downlink scenarios.
  • CSI-RS Channel State Information Reference Signal
  • the technical challenges of intra-band multicarrier operation also include management of CCI.
  • the present disclosure involves a CSI and PMI signaling framework based on UE measurement and feedback.
  • the current specifications lack support for full duplex collaborative devices, which could be beneficial.
  • For the two downlink scenarios there is a need for a CSI reporting mechanism from UEs based on CSI-RS measurements. This mechanism may benefit from a CD and help manage CLI for both the target UE and the co-scheduled UE.
  • Proposal 2 involves operation and signaling with a precoder P at the CD and UE measurement/feedback, with total report to the gNB (Option 1. a) .
  • Proposal 3 involves operation and signaling with a precoder P at the CD and UE measurement/feedback, with separate reports to the gNB and the CD (Option 1. b) .
  • the features include the UE measuring CSI-RS on different frequency bands to acquire estimates of 1) the direct channel (H2) , and 2) the cascaded channel (Hs ⁇ H1) , which may be CD-unprecoded or CD-precoded based on precoder cycling operation. Furthermore, the UE may provide feedback to the gNB, including Rank Indicator (RI) , PMI, Channel Quality Indicator (CQI) , and CD precoder information, based on an extended channel matrix obtained from the direct channel and the (CD-precoded) cascaded channel. Additionally, the UE measures Demodulation Reference Signals (DM-RS) on both frequency bands to acquire estimates of 1) the precoded direct channel, and 2) the gNB precoded (and CD-precoded) cascaded channel.
  • RI Rank Indicator
  • PMI PMI
  • CQI Channel Quality Indicator
  • CD precoder information based on an extended channel matrix obtained from the direct channel and the (CD-precoded) cascaded channel.
  • Proposal 4 involves operation and signaling without a precoder at the CD.
  • Proposal 5 involves operation and signaling with a precoder at the CD and UE measurement /feedback (for downlink scenarios) or feedback to the UE (for uplink scenarios) -total report to the gNB (for downlink scenarios) or to the UE (for uplink scenarios) .
  • Proposal 6 involves operation and signaling with a precoder at the CD and UE measurement /feedback (for downlink scenarios) or feedback to the UE (for uplink scenarios) -separate report to the gNB and the CD (for downlink scenarios) or to the UE and the CD (for uplink scenarios) .
  • Proposal 7 revisits Proposals 4-6, specifically addressing intra-carrier intra-cell CLI for non-full duplex gNB only.
  • the main ideas include extending Proposals 1-3 with a CLI-robust receiver at the target UE during RI/PMI/CQI feedback and data demodulation, as well as enabling co-scheduled UEs to measure CD-precoded CSI-RS and report recommended precoders.
  • the interference types considered in the proposals include: (1) Inter-carrier intra-cell CLI (H cli ⁇ ibe) , which represents interference from the CD’s transmission on Band #2 leaking into the UE’s reception on Band #1, where ibe is a function of the received signal Z b at the CD, the precoder P, frequency offset ⁇ f , and modulation scheme; (2) Intra-carrier intra-cell CLI (H cli ′ ⁇ ue′) , which represents interference from another UE (UE’ ) to the target UE on the same frequency band; and (3) Co-channel interference (CCI) (H cci ⁇ X o_gnb ) , which occurs when the gNB transmits on Band #2 in the non-full duplex scenario, interfering with the CD-to-UE transmission on Band #2.
  • CLI Co-channel interference
  • the CD cycles through N candidate precoders P (1) , P (2) ,..., P (N) from a predefined codebook.
  • the CD applies it to the received CSI-RS and transmits the precoded signal to the UE on Band #2.
  • the UE measures all N precoded CSI-RS instances and selects the optimal precoder P(k * ) that maximizes the overall system performance while considering both the desired signal strength and interference levels.
  • FIG. 12 is a diagram 1200 illustrating a downlink full duplex gNB scenario.
  • FIG. 13 is a diagram 1300 illustrating a communication system in a downlink full duplex gNB scenario.
  • the gNB transmits a reference signal, specifically a CSI-RS, to the UE via two distinct paths.
  • a direct path is that the gNB transmits the CSI-RS directly to the UE on Band #1, denoted as H 2 .
  • the UE will use this CSI-RS to measure the channel between the gNB and the UE.
  • An indirect path is that the gNB transmits the CSI-RS to a CD on Band #1, which performs frequency translation from Band #1 to Band #2 before forwarding the signal to the UE.
  • the UE measures the cascaded channel response H s ⁇ H 1 using this frequency-translated CSI-RS.
  • different streams which are different layers in the MIMO, may be needed. However, there is no need to provide different CSI-RS.
  • the CSI-RS is just a reference signal broadcasted by the gNB and is not precoded.
  • the signals W1 and W2 are spatially multiplexed on the same frequency in a MIMO transmission scheme.
  • the system operates in a manner analogous to multi-user MIMO. Specifically, The UE receives W2 directly, while the CD receives W1. The CD subsequently performs frequency translation on W1 and forwards it to the UE.
  • the UE cannot simultaneously receive W1 and W2 in the same frequency band. Notably, if the UE were equipped with a sufficient number of antennas, joint reception of both signals would be possible.
  • the UE utilizes this signal to measure the aggregated channel response, encompassing both the gNB-to-CD (denoted as H1) and CD-to-UE links (denoted as Hs) . Consequently, the UE receives two instances of the same CSI-RS, one in the original frequency band (direct path, on the blue band) and another in a translated frequency band (indirect path, on the orange band) . Correspondingly, the UE needs to perform two measurements, respectively on the direct channel and on the aggregated channel (i.e., the cascaded channel) . Furthermore, the system may have two precoders, one of them coming through this channel directly to the UE and the other one going through the CD.
  • the UE may provide a CSI feedback report, such as a precoder matrix indicator and Rank Indicator (RI) , to the gNB.
  • a CSI feedback report such as a precoder matrix indicator and Rank Indicator (RI)
  • RI Rank Indicator
  • the same CSI-RS may be transmitted by the gNB in the initial frequency band.
  • the related parameters can be obtained from the following equations.
  • X P 1 X 1 +P 2 X 2 for mu-mimo style
  • X P s S
  • S is a multicast message encoding only one message W1 or multiple messages e.g. W1 &W2.
  • X STBC encoding of W1 and W2.
  • CD RX: Z b H 1 X+N b .
  • the system operates as an effective point-to-point MIMO configuration.
  • the UE observes the received signal vector containing signals from both Band #1 and Band #2 to determine the transmitted data streams.
  • the system needs to find the transmitted symbols while for multicasting scenarios, it needs to determine the multicast message S.
  • the system performance is influenced by several design variables, specifically the precoders P 1 , P 2 , P, and P s .
  • the precoders P 1 and P 2 are conventional precoders applied at the gNB for the transmission streams directed to the CD and directly to the UE, respectively.
  • the precoder P at the CD influences the effective MIMO channel by shaping the cascaded channel response from gNB through CD to UE.
  • the presence of cross-link interference (CLI) increases the effective noise in the system, degrading the overall performance.
  • CLI cross-link interference
  • the framework presents several options for precoder selection and reporting between the UE and gNB.
  • the first option designated as Option 0 and corresponding to Proposal 1, sets the precoder P equal to the identity matrix I, effectively implementing no precoding at the CD. This approach simplifies the system by eliminating the need for precoder selection at the CD.
  • Option 1 When precoder P needs to be selected at the CD, Option 1 employs UE measurement and feedback mechanisms. This option branches into two distinct reporting approaches.
  • Option 1. a which corresponds to Proposal 2, implements a centralized reporting strategy where the UE reports all measurement results and precoder recommendations directly to the gNB. The gNB then communicates the selected precoder to the CD through downlink control signaling.
  • Option 1. b corresponding to Proposal 3, adopts a distributed reporting approach where the UE reports separately to both the gNB and the CD. In this configuration, the UE sends the recommended precoders P 1 and P 2 to the gNB while directly reporting the preferred CD precoder index to the CD, requiring the establishment of a direct communication channel between the UE and CD.
  • the gNB transmits CSI-RS on Band #1, which the UE receives directly to measure the channel H 2 .
  • the CD receives the same CSI-RS, performs frequency translation to Band #2, and forwards it to the UE.
  • the UE measures the cascaded channel H s H 1 from this frequency-translated signal. Based on these measurements, the UE computes and reports PMI and RI for precoders P 1 and P 2 to the gNB.
  • the CD implements precoding with centralized reporting.
  • the CD cycles through N candidate precoders P (1) , P (2) , ..., P (N) from a predefined codebook.
  • the CD applies it to the received CSI-RS and transmits the precoded signal to the UE on Band #2.
  • the UE measures all N precoded CSI-RS instances and selects the optimal precoder P (k * ) that maximizes system performance.
  • the UE reports the selected precoder index k * along with the recommended precoders P 1 and P 2 to the gNB.
  • the gNB then sends a downlink indication to the CD specifying which precoder P (k * ) to use.
  • Proposal 3 (Option 1. b) , the system operates similarly to Proposal 2 but with distributed reporting.
  • the UE reports the recommended precoders P 1 and P 2 to the gNB, while directly reporting the selected precoder index k * to the CD.
  • This approach requires establishing a direct communication channel between the UE and CD, which may be more complex to implement than the centralized reporting approach in Proposal 2.
  • the precoder cycling operation can be optimized to reduce overhead. Instead of requiring the gNB to transmit CSI-RS N times, the CD can store the received CSI-RS from the first transmission and then apply different precoders and retransmit N times over N resources. This approach significantly reduces the signaling overhead on the gNB-to-CD link while maintaining the ability to evaluate multiple precoding options.
  • FIG. 14 is a diagram 1400 illustrating a communication process among the gNB, CD and UE, corresponding to Proposal 1.
  • Proposal 1 involves a scenario where the CD has no precoder. Its related calculation follows the following equations.
  • Rx design is similar to Y1 robust receiver.
  • DM-RS precoded by P 1 and P 2 and robust Rx are based on estimated covariance matrix of
  • the gNB transmits CSI-RS which the UE receives through two paths: directly on Band #1 to measure H 2 , and via the CD which performs frequency translation to Band #2 to measure the cascaded channel H s H 1 . Based on these measurements and the estimated interference covariance matrix, the UE determines optimal precoders P 1 and P 2 and reports them to the gNB via PMI and RI feedback.
  • Proposal 1 makes it particularly suitable for scenarios where minimizing latency and implementation complexity at the CD is critical. Since the CD only performs amplify-and-forward with frequency translation and no precoding, the processing delay can be kept well below the cyclic prefix duration. This approach serves as a baseline for comparison with more complex proposals that incorporate CD precoding.
  • FIG. 15 is a diagram 1500 illustrating a communication process among the gNB, CD and UE, corresponding to Proposal 2. It illustrates option 1. a: reporting everything to gNB.
  • a precoder P is selected at the CD to optimize the cascaded channel.
  • the gNB transmits CSI-RS on Band #1, which is received by both the UE (directly) and the CD.
  • the CD applies a precoder P to the received CSI-RS, performs frequency translation from Band #1 to Band #2, and forwards it to the UE. This enables optimization of the effective MIMO channel and can reduce interference effects.
  • the CD cycles through a codebook of N candidate precoders P (1) , P (2) , ..., P (N) .
  • the CD applies it to the received CSI-RS from the gNB and transmits the precoded and frequency-translated signal to the UE on Band #2.
  • the UE measures all N precoded CSI-RS instances on Band #2, evaluating the cascaded channel response H s P (k) H 1 for each precoder.
  • the UE determines and reports to the gNB: 1) the optimal precoder P 1 for the gNB-to-CD link, 2) the optimal precoder P 2 for the direct gNB-to-UE link, and 3) the preferred precoder index k * indicating which precoder P (k * ) the CD should use.
  • the precoder used by the CD may be digital or analog.
  • the analog precoder is simpler, which simply applies different weights at the antenna, but poses more challenges for minimizing latency.
  • the CD needs to decode the CSI-RS into the digital domain (not to bits, but the symbol level) , apply a precoder, and then retransmit the CSI-RS.
  • the UE measures the channel quality for each of the N precoded CSI-RS instances received on Band #2. While the transmitted CSI-RS from the gNB is identical, the received signals at the UE differ due to the different precoders applied by the CD. The UE evaluates the overall system performance considering both the direct channel on Band #1 and the cascaded channel on Band #2, then selects the optimal precoder P (k * ) by determining which index k * in the precoder sequence maximizes the effective channel capacity.
  • the UE may determine selection of these precoders.
  • the UE then feeds this information directly to the gNB, which in turn instructs the CD on which precoder P to use.
  • This approach is simpler and more practical because it eliminates the need for a communication link (e.g., a dedicated control channel) between the UE and the CD.
  • the UE performs joint optimization when selecting the precoders, as the choice of precoder P at the CD impacts the performance on both Band #1 and Band #2.
  • the effective received signal at the UE can be expressed as where Y b and Y o represent the received signals on Band #1 and Band #2 respectively.
  • the UE must compute P, P 1 , and P 2 based on the overall performance across both frequency bands.
  • the gNB Upon receiving the CSI feedback from the UE, the gNB sends a downlink control signal to the CD indicating the selected precoder P (k * ) . This requires a new downlink field in the control signaling, such as in the Physical Downlink Control Channel (PDCCH) .
  • the gNB uses the reported precoders P 1 and P 2 for actual data transmission, with P 1 applied to the data stream X 1 intended for relay through the CD, and P 2 applied to the data stream X 2 transmitted directly to the UE.
  • PDCCH Physical Downlink Control Channel
  • an optimized implementation allows the CD to store the received CSI-RS from a single transmission.
  • the CD then applies the N different precoders to this stored signal and transmits the precoded versions sequentially to the UE. This approach significantly reduces the overhead on the gNB-to-CD link while maintaining the ability to evaluate all precoding options.
  • FIG. 16 is a diagram 1600 illustrating a communication process among the gNB, CD and UE, corresponding to Proposal 3. It illustrates option 1. b: reporting separately to gNB and CD.
  • Option 1. the UE reports all measurement results directly to the gNB without any communication with the CD, whereas in Option 1. b, the UE sends reports to both the gNB and the CD.
  • Proposal 3 introduces direct UE-CD reporting, which adds complexity.
  • Precoder cycling may be required to select a proper precoder.
  • CSI-RS transmissions on the H 1 path gNB to CD, a first part of the cascaded channel: instead of repeating the same reference signal N times, it can be transmitted once. The CD can then cycle through different precoders and retransmit the signal multiple times. This reduces the overhead significantly.
  • Band #1 i.e., the H 1 path
  • Band #2 precoded CSI-RS from CD to UE, i.e., the H s path, a second part of the cascaded channel
  • the precoders can be selected based on CSI-RS and the covariance matrix.
  • Proposals 1-3 do not consider the CLI (denoted as H cli ) that this CD transmission causes on the direct path from the gNB (i.e., the H 2 path) .
  • Proposals 4, 5, and 6 consider the CLI.
  • the main differences between Proposals 1-3 and Proposals 4-6 include extending the framework with a CLI-robust receiver at the intended UE during RI/PMI/CQI feedback and data demodulation. In the presence of CLI, the UE needs to select precoders P 1 and P 2 while accounting for CLI effects through the estimated covariance matrix of interference and noise. This changes both the precoder selection criteria and the receiver design.
  • Option 1. b (Proposal 3) , establishing a direct communication channel between the CD and UE introduces additional complexity compared to Option 1. a. While Option 1. aonly requires adding a new downlink field in the control signaling (e.g., PDCCH) for the gNB to inform the CD which precoder to use, Option 1. b necessitates a separate control channel infrastructure between the UE and CD. This architectural difference makes Option 1. amore practical for initial deployment.
  • the control signaling e.g., PDCCH
  • the UE evaluates the overall system performance considering both the direct channel on Band #1 and the cascaded channel on Band #2.
  • the selection criterion maximizes the effective channel capacity while considering the coupling between the choice of P at the CD and the choices of P 1 and P 2 at the gNB.
  • the effective received signal model incorporates the interference term H cli ⁇ ibe, where ibe is a function of the received signal Z b at the CD, the precoder P, the frequency offset ⁇ f , and the modulation scheme.
  • This non-linear dependency of ibe on the precoder P significantly complicates the precoder optimization problem, as the interference level changes with the precoder selection.
  • FIG. 17 is a diagram 1700 illustrating the inter-carrier intra-cell CLI H cli . Its calculation may follow the following processes.
  • the system implements a CLI-robust PMI recommendation mechanism to manage interference in the cooperative MIMO framework.
  • This mechanism enables the UE to provide precoder recommendations that balance the competing objectives of maximizing desired signal strength while minimizing cross-link interference.
  • the UE recommends that the CD utilize a specific PMI for the precoder P to prevent the generation of high cross-link interference H cli on Band #1.
  • This recommendation aims to minimize the signal leakage from the CD’s transmission on Band #2 that would otherwise interfere with the UE’s reception of the direct signal from the gNB on Band #1.
  • the UE must report Channel State Information (CSI) to the CD for the computation of the precoder P to achieve high Channel Quality Indicator (CQI) on Band #2.
  • CSI Channel State Information
  • CQI Channel Quality Indicator
  • ibe is a function of P and X, hence a function of P, P 1 , and P 2 .
  • the precoder calculation for P, P 1 , and P 2 must be modified when the interference and noise term is accounted for.
  • ibe represents the interference from the CD’s transmission on Band #2 that leaks into the UE’s reception on Band #1.
  • This interference is a non-linear function of the received signal Z b at the CD, the precoder P applied at the CD, the frequency offset ⁇ f between Band #1 and Band #2, and the modulation scheme employed.
  • the non-linear dependency of ibe on P significantly complicates the precoder optimization problem because the interference level changes dynamically with the precoder selection.
  • This CLI management is particularly critical in the full duplex collaborative device scenario because the CD simultaneously receives signals from the gNB on Band #1 while transmitting to the UE on Band #2. Without proper CLI management through optimized precoder selection, the signal leakage from Band #2 to Band #1 can severely degrade the quality of the direct gNB-to-UE transmission on Band #1, potentially negating the benefits of the cooperative MIMO scheme.
  • the CLI-robust PMI recommendation mechanism forms a key component of Proposals 4, 5, and 6, which extend the basic proposals (Proposals 1, 2, and 3) to explicitly account for interference effects.
  • the UE’s precoder selection criteria must balance two competing objectives: maximizing the desired signal strength through the cascaded path H s PH 1 on Band #2 while minimizing the CLI H cli ⁇ ibe that affects reception on Band #1. This multi-objective optimization requires the UE to evaluate the overall system performance across both frequency bands when recommending precoders.
  • FIG. 18 is a diagram 1800 illustrating a communication process among the gNB, CD and UE, corresponding to Proposal 4. It revisits Proposal 1, but considers the presence of CLI. Its process may follow the following procedures.
  • P 1 and P 2 selected are based on CSI-RS and estimated covariance matrix of then reported to gNB.
  • Rx design is similar to Y1 robust receiver.
  • DM-RS precoded by P 1 and P 2 and robust Rx are based on estimated covariance matrix of CSI feedback (PMI and RI) [P 1 P 2 ] to gNB selected are based on CSI-RS and estimated covariance matrix of Both used to detect transmit messages.
  • Robust Rx is based on estimated covariance matrix of
  • Proposal 4 extends Proposal 1 by incorporating CLI-aware processing throughout the system. While Proposal 1 assumes negligible interference and focuses solely on maximizing the desired signal strength, Proposal 4 explicitly accounts for the cross-link interference H cli ⁇ ibe from the CD’s transmission on Band #2 leaking into the UE’s reception on Band #1. This interference term is a non-linear function of the CD’s received signal Z b , making the optimization problem more complex.
  • the CLI-robust receiver design in Proposal 4 utilizes the estimated covariance matrix of the combined noise and interference terms to perform interference rejection combining (IRC) or similar techniques. This enables the UE to suppress the CLI while demodulating the desired signals.
  • the precoder selection criteria for P 1 and P 2 are modified to balance maximizing the desired signal power against minimizing the interference levels, resulting in a more robust system performance in the presence of CLI.
  • the system cannot actively control the CLI through CD precoder optimization.
  • the gNB precoders P 1 and P 2 can still be optimized to minimize the overall interference impact while maintaining good signal quality on both the direct path (Band #1) and the cascaded path (Band #2) .
  • This simplified approach serves as a baseline for comparison with Proposals 5 and 6, which introduce CD precoding for additional CLI management capability.
  • FIG. 19 is a diagram 1900 illustrating a communication process among the gNB, CD and UE, corresponding to Proposal 5. It revisits Proposal 2, but considers the presence of CLI. Its process may follow the following procedures.
  • Option 1. awith CLI H cli ⁇ ibe P 1 and P 2 selected are based on CSI-RS and estimated covariance matrix of then reported to gNB. Rx design is similar to Y1 robust receiver.
  • DM-RS precoded by P 1 and P 2 and robust Rx are based on estimated covariance matrix of P to be selected -Option 1: UE measurement and feedback CSI feedback to gNB: UE decides preferred P (k * ) (and report corresponding index) jointly with [P 1 P 2 ] (or first decides P and then [P 1 P 2 ] ) selected based on CSI-RS and estimated covariance matrix of Hence PMI k * feedback for P and PMI feedback for [P 1 P 2 ] .
  • Robust Rx is based on estimated covariance matrix of
  • Proposal 5 extends Proposal 2 by incorporating CLI-aware processing throughout the system.
  • the CD cycles through N candidate precoders P (1) , P (2) , ..., P (N) from a predefined codebook, applying each to the received CSI-RS before frequency translation and transmission to the UE on Band #2.
  • the UE measures all N precoded CSI-RS instances while accounting for the interference covariance matrix, enabling joint optimization of the CD precoder P and the gNB precoders P 1 and P 2 in the presence of CLI.
  • precoders P 1 , P 2 , and P are based on CSI-RS measurements and the covariance matrix of noise and interference.
  • the covariance matrix at the time of CSI feedback is a function of P, P 1 , and P 2 . While the dependence on P can be measured from the N CSI-RS transmissions, the dependence on P 1 and P 2 is difficult to determine since the nonlinear function ibe is unknown. This interdependency significantly complicates the precoder optimization problem.
  • a hierarchical precoder cycling approach can be employed: first, cycle through a codebook of M [P 1 P 2 ] precoders; second, for each given precoder pair [P 1 P 2 ] , cycle through a codebook of N precoders P; third, measure all M ⁇ N precoded CSI-RS instances and select the combination of [P 1 P 2 ] and P that maximizes the performance based on CSI-RS measurements and the covariance matrix of noise and interference.
  • This approach allows the covariance matrix to be measured as a function of the applied precoders in the codebook.
  • the drawback is increased latency since M ⁇ N precoded CSI-RS transmissions need to be transmitted and measured.
  • An alternative approach involves transmitting M+N precoded CSI-RS: when M [P 1 P 2 ]precoded CSI-RS are transmitted, only one precoder P is used, and when N CSI-RS cycling through P are transmitted, only one precoder pair [P 1 P 2 ] is used. While this approach does not capture the full combination of [P 1 P 2 ] and P precoders, it significantly reduces the CSI-RS transmission time compared to the hierarchical approach.
  • FIG. 20 is a diagram 2000 illustrating a communication process among the gNB, CD and UE, corresponding to Proposal 6. It revisits Proposal 3, but considers the presence of CLI. Its process may follow the following procedures.
  • Option 1. b with CLI H cli ⁇ ibe P 1 and P 2 selected are based on CSI-RS and estimated covariance matrix of then reported to gNB. Rx design is similar to Y1 robust receiver.
  • DM-RS precoded by P 1 and P 2 and robust Rx are based on estimated covariance matrix of P to be selected -Option 1: UE measurement and feedback CSI feedback to gNB: UE decides preferred P (k * ) jointly with [P 1 P 2 ] (or first decides P and then [P 1 P 2 ] ) . Reports selected [P 1 P 2 ] to gNB.
  • CSI feedback to CD UE decides preferred P (k * ) jointly with [P 1 P 2 ] (or first decides P and then [P 1 P 2 ] ) and reports selected k * to CD. Both used to detect transmit messages.
  • Robust Rx based on estimated covariance matrix of
  • This option 1. b requires establishing connection between CD and UE. This may be more difficult than adding a downlink field in option 1. afor gNB to inform CD.
  • Proposal 6 extends Proposal 3 by incorporating CLI-aware processing throughout the system while maintaining the distributed reporting architecture. Similar to Proposal 5, the CD cycles through N candidate precoders P (1) , P (2) , ..., P (N) from a predefined codebook, applying each to the received CSI-RS before frequency translation and transmission to the UE on Band #2. However, unlike Proposal 5 which uses centralized reporting through the gNB, Proposal 6 maintains the distributed reporting structure where the UE reports the selected precoders P 1 and P 2 to the gNB while directly reporting the preferred precoder index k * to the CD.
  • the CLI-aware precoder selection in Proposal 6 requires the UE to jointly optimize all three precoders P, P 1 , and P 2 while accounting for the interference covariance matrix.
  • the optimization problem becomes significantly more complex than in Proposal 3 because the interference term H cli ⁇ ibe is a non-linear function of the precoder P, requiring the UE to evaluate how each candidate precoder affects both the desired signal strength through the cascaded path H s PH 1 and the interference level on Band #1. This joint optimization ensures that the selected precoders maximize overall system performance across both frequency bands while minimizing the detrimental effects of CLI.
  • the distributed reporting architecture in Proposal 6 while adding implementation complexity due to the required UE-CD communication channel, offers potential advantages in terms of reduced latency for CD precoder updates and reduced signaling overhead on the gNB-CD link.
  • the practical challenges of establishing and maintaining a reliable control channel between the UE and CD may make the centralized reporting approach of Proposal 5 more suitable for initial deployments.
  • the choice between Proposals 5 and 6 ultimately depends on the specific deployment scenario and the relative importance of signaling efficiency versus implementation complexity.
  • FIG. 21 is a diagram 2100 illustrating a downlink non-full duplex gNB scenario.
  • FIG. 22 is a diagram 2200 illustrating a communication system in a downlink non-full duplex gNB scenario.
  • the related calculation may follow the following equations. In the equations, SI is ignored, CLI is accounted for, CCIs from gNB TX to CD RX inter-carrier and from gNB TX to UE RX inter-carrier are ignored, CCI from gNB TX to UE RX intra-carrier is accounted for.
  • the gNB lacks the capability to simultaneously transmit and receive on different frequency bands. Consequently, when the gNB transmits to the UE and CD on Band #1, it also transmits on Band #2 to serve other UEs in the network.
  • This introduces a fourth precoder P 3 for the gNB’s transmission on Band #2, denoted as X o_gnb P 3 X 3 .
  • the signal X 3 represents data intended for other UEs, and its transmission creates co-channel interference (CCI) with the CD-to-UE transmission on Band #2.
  • CCI co-channel interference
  • the key distinction from the full duplex scenario lies in the interference pattern. While the full duplex scenario experiences inter-UE CLI (from UE’ transmitting to gNB on Band #2) , the non-full duplex scenario experiences CCI from the gNB’s own transmission on Band #2. This CCI, represented by the term H cci X o_gnb in the signal model, directly impacts the UE’s reception of the relayed signal from the CD on Band #2.
  • CD RX Z b H 1 X+N b .
  • the system operates as an effective point-to-point MIMO configuration where the received signal vector is observed to determine the transmitted symbols
  • the design of the system involves four precoding matrices, namely P 1 , P 2 , P, and P 3 , all of which significantly influence the overall system performance.
  • P 1 , P 2 , and P 3 are conventional precoders applied at the gNB, while P serves as the precoder at the collaborative device that influences the effective MIMO channel characteristics.
  • the presence of the fourth precoder P 3 introduces additional complexity compared to the full duplex scenario denoted as (a. 1) .
  • the precoder P 3 is specifically used for the gNB’s transmission on Band #2 to other UEs in the network, and its design directly impacts the performance of the target UE due to the co-channel interference it creates.
  • both cross-link interference (CLI) and co-channel interference (CCI) contribute to an increase in the effective noise level experienced by the system.
  • the MIMO system configuration requires careful observation of the received signal vector to accurately recover the transmitted signal vector
  • the optimization of the four design variables P 1 , P 2 , P, and P 3 must be performed jointly to achieve optimal system performance. While P 1 , P 2 , and P 3 function as conventional precoders that shape the transmitted signals at the gNB, the precoder P at the collaborative device plays a unique role in determining the effective MIMO channel between the gNB and the UE through the relay path.
  • the additional complexity introduced by P 3 in this scenario compared to the baseline case (a. 1) , stems from the need to balance service quality for multiple UEs while managing the interference environment created by simultaneous transmissions on Band #2.
  • the combined effects of CLI and CCI significantly degrade the signal quality by increasing the effective noise floor of the system.
  • the presence of the fourth precoder P 3 in the non-full duplex scenario introduces additional optimization complexity. While in the full duplex scenario, the precoder optimization problem involves three variables (P, P 1 , P 2 ) , the non-full duplex case requires joint optimization of four precoders.
  • the precoder P 3 must be designed to serve other UEs on Band #2 while minimizing the CCI H cci X o_gnb experienced by the target UE. This creates a multi-objective optimization problem where the gNB must balance service quality for multiple UEs across different frequency bands.
  • the CCI term H cci X o_gnb in the received signal model represents a deterministic interference component, unlike the stochastic interference from UE’ in the full duplex scenario.
  • This deterministic nature allows for more sophisticated interference management techniques, as the gNB has complete knowledge of the transmitted signal X o_gnb and can potentially design P 3 to minimize interference to the target UE while maintaining acceptable service quality for other UEs.
  • this requires coordination between the precoder designs for different UEs, significantly increasing the computational complexity at the gNB.
  • the present disclosure proposes the framework to design and report P 1 , P 2 , P, P 3 between UE and gNB, related RI and PMI feedback signaling.
  • the precoder selection framework presents several options for system implementation.
  • Option 0 which corresponds to Proposal 1
  • the precoder P must be selected through specific measurement and feedback mechanisms.
  • Option 1 For scenarios requiring precoder selection at the collaborative device, Option 1 employs user equipment measurement and feedback procedures. This option branches into two distinct reporting approaches. Option 1. a, corresponding to Proposal 2, implements a centralized reporting mechanism where all measurement results and precoder recommendations are reported to the gNodeB. In contrast, Option 1. b, corresponding to Proposal 3, utilizes a distributed reporting approach where feedback is sent separately to both the gNodeB and the collaborative device.
  • Proposals 1 through 3 address system operation without explicit consideration of cross-link interference, focusing primarily on optimizing the desired signal paths. Meanwhile, Proposals 4 through 6 extend these basic proposals by incorporating cross-link interference-aware processing, enabling more robust system performance in the presence of interference between Band #1 and Band #2 transmissions
  • FIG. 23 is a diagram 2300 illustrating another communication process among the gNB, CD and UE, corresponding to Proposal 1 for the downlink non-full duplex gNB scenario.
  • the related calculation may follow the following equations.
  • Option 0 -P I CSI-RS to measure H 2 and H s H 1
  • the gNB transmits CSI-RS which the UE receives through two paths: directly on Band #1 to measure H 2 , and via the CD which performs frequency translation to Band #2 to measure the cascaded channel H s H 1 .
  • the UE Based on these channel measurements, the UE computes optimal precoders P 1 and P 2 for the gNB transmissions.
  • the precoder P 1 is applied to the data stream intended for relay through the CD, while P 2 is applied to the data stream transmitted directly to the UE.
  • the UE reports these precoder recommendations to the gNB through PMI and RI feedback.
  • CCI co-channel interference
  • the CD implements a precoder cycling operation where it applies different precoders from a predefined codebook to the received CSI-RS before frequency translation and transmission to the UE.
  • Proposal 2 (Option 1. a) , the CD cycles through N candidate precoders P(1) , P (2) , ..., P (N) from a codebook. For each precoder P (k) , the CD applies it to the received CSI-RS and transmits the precoded signal to the UE on Band #2. The UE measures all N precoded CSI-RS instances and selects the optimal precoder P (k * ) that maximizes system performance.
  • the UE reports the selected precoder index k * along with the recommended precoders P 1 and P 2 to the gNB.
  • the gNB then sends a downlink indication to the CD specifying which precoder P(k * ) to use. This centralized reporting approach avoids the need for a direct control channel between the UE and CD.
  • Proposal 3 (Option 1. b) , the system operates similarly but with distributed reporting.
  • the UE reports the recommended precoders P 1 and P 2 to the gNB, while directly reporting the selected precoder index k * to the CD. This approach requires establishing a communication channel between the UE and CD.
  • the UE Based on the selected precoder P, the UE builds the effective channel matrix then selects P 1 and P 2 from the codebook that optimize the overall system performance across both Band #1 and Band #2, and reports these selections to the gNB.
  • FIG. 24 is a diagram 2400 illustrating another communication process among the gNB, CD and UE, corresponding to Proposal 2. It illustrates option 1. a: reporting everything to gNB.
  • FIG. 25 is a diagram 2500 illustrating another communication process among the gNB, CD and UE, corresponding to Proposal 3. It illustrates option 1. b: reporting separately to gNB and CD.
  • FIG. 26 is a diagram 2600 illustrating management of inter-carrier intra-cell CLI.
  • a new downlink field may be required in DL control signaling (e.g., Physical Downlink Control Channel (PDCCH) ) for the gNB to indicate to the CD which precoder to use at the CD.
  • DL control signaling e.g., Physical Downlink Control Channel (PDCCH)
  • Option 1 amay use N CSI-RS transmission from gNB but does not require any buffering and operates without latency at the CD. This option may also be implemented with a single CSI-RS transmission from the gNB, assuming a buffer at the CD to store the CSI-RS before transmission in N phases to the UE.
  • H s PH 1 is a function of P and the design of P to maximize the rate performance would be a function of H 1 and H s .
  • optimal choice of P would be V S LU 1 ′where L is the power allocation among streams applied at the CD. If uniform power allocation at CD, then optimal choice of L would look like V s U 1 ′which is still a function of H S and H 1 characteristics.
  • the design of the precoder P at the CD plays a crucial role in the overall system performance.
  • P is optimally designed based on the singular value decomposition (SVD) of the channels H 1 and H S , it effectively aligns the transmitted signal with the channel eigenmodes, maximizing the signal power transfer from the gNB through the CD to the UE.
  • This optimization must consider the coupling between the precoder choices, as the selection of P directly impacts the effective channel matrix seen by the UE.
  • the precoder design must additionally account for the co-channel interference (CCI) term H cci X o_gnb that arises from the gNB’s transmission on Band #2.
  • CCI co-channel interference
  • This interference term unlike the CLI from UE’ in the full duplex scenario, is deterministic and known at the gNB, allowing for more sophisticated interference management through coordinated precoder design across all four precoders P, P 1 , P 2 , and P 3 .
  • H cli The process of managing inter-carrier intra-cell cross-link interference, denoted as H cli , involves several key procedures that focus on CLI-robust precoding matrix indicator (PMI) recommendations and restrictions.
  • PMI precoding matrix indicator
  • the PMI recommendation process plays a crucial role.
  • the user equipment (UE) provides recommendations to the collaborative device (CD) regarding the selection of the precoding matrix indicator for the precoder P.
  • the primary objective of these recommendations is to prevent the creation of high cross-link interference H cli on Band #1.
  • the UE must also report channel state information (CSI) to the CD to enable proper computation of the precoder P that achieves high channel quality indicator (CQI) on Band #2.
  • CSI channel state information
  • CQI channel quality indicator
  • Choice of P impacts Band #2 and Band #1 resources at UE and choice of P 1 &P 2 dependent on /coupled with choice of P, hence P, P 1 &P 2 to be computed are based on overall performance across both resources Need to tackle the effect of CLI H cli ⁇ ibe.
  • the challenge is that ibe is function of P and X, hence function of P, P 1 , P 2 .
  • the non-linear dependency of the interference term ibe on the precoder P creates a complex optimization problem.
  • the optimization must jointly consider the desired signal enhancement through the cascaded path and the CLI minimization on the direct path.
  • the interference term in the Band #2 reception changes from H cli ′ ⁇ ue′ (interference from UE’ in the full duplex case) to H cci ⁇ X o_gnb (co-channel interference from gNB’s own transmission) .
  • This difference in interference sources requires different optimization strategies for precoder selection, particularly for the precoder P 3 which must balance serving other UEs on Band #2 while minimizing interference to the target UE.
  • a victim UE recommends that the collaborative device (CD) avoid using certain restricted PMI values.
  • the choice of the precoder P at the CD has significant impacts on both Band #2 and Band #1 resources at the UE.
  • This restriction approach is similar in principle to the PMI recommendation mechanism, where the UE provides guidance to optimize system performance while minimizing interference.
  • the CLI-robust rank recommendation and restriction process is based on the comprehensive signal model Using this signal model, the UE computes the rank indicator (RI) that accounts for both the desired signal components and the interference terms. The computed RI is then reported to the gNB to enable appropriate rank adaptation in the presence of cross-link interference and co-channel interference.
  • RI rank indicator
  • the framework also incorporates a Friendly PMI mechanism, which provides additional coordination between devices to further optimize the precoding selection and minimize interference across the network.
  • the CLI robust receiver design has already been utilized as an integral part of the PMI recommendation process described above.
  • This receiver employs interference rejection combining techniques based on the estimated covariance matrix of the combined noise and interference terms, enabling effective suppression of both cross-link interference on Band #1 and co-channel interference on Band #2 while preserving the desired signal components from both the direct and cascaded transmission paths.
  • the CLI-robust receiver design employs interference rejection combining (IRC) techniques that utilize the estimated covariance matrix of the combined noise and interference terms.
  • IRC interference rejection combining
  • this covariance matrix must account for both the CLI term H cli ⁇ ibe on Band #1 and the CCI term H cci ⁇ X o_gnb on Band #2.
  • the receiver design aims to suppress these interference components while preserving the desired signal components from both the direct path and the cascaded path through the CD.
  • the framework presented for Proposals 4, 5, and 6 in the non-full duplex gNB scenario maintains the same signaling procedures as the full duplex case but with modified optimization criteria that account for the different interference patterns. This consistency in signaling framework across different deployment scenarios simplifies implementation while allowing for scenario-specific optimization of the precoding matrices to maximize system performance under varying interference conditions.
  • FIG. 27 is a diagram 2700 illustrating another communication process among the gNB, CD and UE, corresponding to Proposal 4 for the downlink non-full duplex gNB scenario. Its process may follow the following procedures.
  • P 1 and P 2 selected are based on CSI-RS and estimated covariance matrix of then reported to gNB.
  • Rx design is similar to Y1 robust receiver.
  • DM-RS precoded by P 1 and P 2 and robust Rx are based on estimated covariance matrix of
  • the key distinction from the full duplex scenario lies in the interference term on Band #2: instead of managing interference from UE’ (H cli ′ ⁇ ue′) , the system must handle co-channel interference from the gNB’s own transmission on Band #2 (H cci X o_gnb ) .
  • This CCI is deterministic and known at the gNB, allowing for coordinated interference management through the optimization of precoders P 1 , P 2 , and potentially P 3 (for the gNB’s transmission on Band #2) .
  • the CLI-robust receiver in Proposal 4 utilizes the estimated covariance matrix to perform interference rejection combining, suppressing both the cross-link interference H cli ⁇ ibe on Band #1 and the co-channel interference H cci X o_gnb on Band #2.
  • the precoder selection criteria for P 1 and P 2 must balance maximizing the desired signal power while minimizing the impact of both interference types across the two frequency bands.
  • FIG. 28 is a diagram 2800 illustrating another communication process among the gNB, CD and UE, corresponding to Proposal 5 for the downlink non-full duplex gNB scenario. Its process may follow the following procedures.
  • Option 1. awith CLI H cli ⁇ ibe P 1 and P 2 selected are based on CSI-RS and estimated covariance matrix of then reported to gNB. Rx design is similar to Y1 robust receiver. DM-RS precoded by P 1 and P 2 and robust Rx are based on estimated covariance matrix of
  • precoders P 1 , P 2 , and P relies on Channel State Information Reference Signal (CSI-RS) measurements combined with the estimated covariance matrix of noise and interference.
  • CSI-RS Channel State Information Reference Signal
  • precoder cycling may be used for P 1 P 2 and for P in a hierarchical manner: 1) cycle through a codebook of M [P 1 P 2 ] precoders, 2) for a given precoder P 1 P 2 , cycle through a codebook of N P precoders, 3) then measure all M ⁇ N precoded CSI-RS and decide the combination of P 1 P 2 and P that maximizes the performance based on CSI-RS and covariance matrix of noise and interference.
  • covariance matrix will change as a function of the applied precoder in the codebook, hence dependence of covariance matrix on P 1 P 2 P will be measured.
  • the drawback of the method is the increased latency since M ⁇ N precoded CSI-RS need to be transmitted and measured.
  • M+N precoded CSI-RS transmitted when M [P 1 P 2 ] precoded CSI-RS are transmitted, only one precoder P is used, and when N CSI-RS cycling through P are transmitted, only one precoder [P 1 P 2 ] is used.
  • This approach is not as effective as the previous one, as it does not capture the combination of [P 1 P 2 ] and P precoders. However, it does reduce the time required for CSI-RS transmission.
  • Proposal 5 introduces additional complexity through the CD precoding capability while managing the unique interference pattern where the gNB transmits on Band #2.
  • the precoder cycling operation enables the UE to evaluate how different CD precoders P (k) affect both the desired signal enhancement through the cascaded path H s PH 1 and the interference levels.
  • the optimization must jointly consider the CLI term H cli ⁇ ibe that depends non-linearly on P and the CCI term H cci X o_gnb that depends on the gNB’s precoder P 3 for Band #2 transmission.
  • the centralized reporting mechanism in Proposal 5 where all feedback goes through the gNB, simplifies the system architecture compared to distributed reporting.
  • the gNB receives the UE’s recommendations for all precoders and coordinates their selection, including sending the downlink indication to the CD specifying which precoder P (k * ) to use. This centralized approach enables better coordination of interference management across all active links in the system.
  • FIG. 29 is a diagram 2900 illustrating another communication process among the gNB, CD and UE, corresponding to Proposal 6 for the downlink non-full duplex gNB scenario. Its process may follow the following procedures.
  • Option 1. b with CLI H cli ⁇ ibe P 1 and P 2 selected are based on CSI-RS and estimated covariance matrix of then reported to gNB. Rx design is similar to Y1 robust receiver. DM-RS precoded by P 1 and P 2 and robust Rx are based on estimated covariance matrix of
  • the precoder $P$ needs to be selected through a UE measurement and feedback mechanism.
  • This selection process follows Option 1, where the UE performs channel measurements and provides feedback to enable optimal precoder selection at the CD.
  • This Option 1. b approach requires establishing a direct connection between the CD and the UE for control signaling purposes. This requirement introduces additional implementation complexity compared to Option 1. a. Specifically, establishing and maintaining a dedicated communication channel between the CD and UE may be more difficult to implement than the alternative approach in Option 1. a, which only requires adding a new downlink field in the control signaling (such as in the PDCCH) for the gNB to inform the CD about which precoder to use.
  • the centralized approach of Option 1. a where all signaling flows through the gNB, avoids the need for direct CD-UE communication infrastructure, making it more practical for initial deployments.
  • Proposal 6 extends Proposal 3 with CLI-aware processing while maintaining the distributed reporting architecture.
  • the UE performs joint optimization of all precoders while accounting for both the CLI on Band #1 and the CCI on Band #2.
  • the distributed reporting where the UE reports P 1 and P 2 to the gNB while directly reporting the preferred CD precoder index k * to the CD, requires additional signaling infrastructure but can reduce latency for CD precoder updates.
  • the practical implementation challenges of Proposal 6 in the non-full duplex scenario include establishing and maintaining the UE-CD communication channel while the gNB is actively transmitting on Band #2.
  • the CCI from the gNB’s transmission may affect not only the CD-to-UE data transmission but also the UE-to-CD control signaling, requiring robust signaling design to ensure reliable precoder feedback delivery.
  • FIG. 30 is a diagram 3000 illustrating management of intra-carrier intra-cell CLI. Its process may follow the following procedures.
  • Proposal 7 specifically addresses the management of intra-carrier intra-cell CLI, denoted as H cli ′, which represents interference from another UE (UE’ ) to the target UE on the same frequency band. This differs from the inter-carrier CLI (H cli ) addressed in Proposals 4-6, which represents interference between different frequency bands.
  • the intra-carrier CLI occurs when UE’ transmits to the gNB on Band #2 while the CD is simultaneously transmitting to the target UE on the same Band #2.
  • the system When managing intra-carrier intra-cell cross-link interference (CLI) , the system implements a CLI-robust precoding matrix indicator (PMI) recommendation and restriction mechanism.
  • PMI precoding matrix indicator
  • UE’ provides recommendations to the gNodeB (gNB) regarding the selection of precoder P at the collaborative device (CD) .
  • the objective of UE’ is to recommend a precoder P that minimizes the interference term H cli ′PH 1 , where H cli ′represents the channel from the CD to UE’ , P is the precoder applied at the CD, and H 1 is the channel from the gNB to the CD.
  • the received signal can be expressed mathematically.
  • H UE′ represents the direct channel from the gNB to UE’
  • X o_gnb is the signal transmitted by the gNB on Band #2 intended for UE’
  • M o_UE′ represents the noise at UE’ .
  • the interference terms consist of H cli ′PH 1 X, which represents the interference from the gNB’s transmission to the UE through the CD relay path, and H cli ′PN b , which represents the noise amplification through the same interference path.
  • X represents the signal transmitted by the gNB on Band #1
  • N b is the noise at the CD.
  • This CLI-robust PMI recommendation mechanism enables UE’ to actively participate in the interference management process by providing feedback that helps minimize the interference it experiences from the cooperative transmission intended for the target UE.
  • the gNB can then use this feedback, along with recommendations from the target UE, to make an informed decision about the optimal precoder selection at the CD that balances the performance requirements of multiple users in the network.
  • the gNB has no direct knowledge of the covariance matrix of interference at the UE, making centralized coordination challenging. Therefore, Option 1. a (centralized reporting through gNB) is preferred over Option 1. b (distributed reporting) for practical implementation.
  • FIG. 31 is a diagram 3100 illustrating another communication process among the gNB, CD and UE, corresponding to Proposal 7.
  • both the target UE and the potentially interfering UE’ participate in the precoder selection process. While the target UE measures the cascaded channel and recommends precoders to maximize its desired signal quality, UE’ simultaneously monitors the CSI-RS transmissions and recommends precoders that minimize the interference it causes to the target UE. This coordinated approach enables the gNB to make informed decisions that balance the performance requirements of multiple UEs in the network.
  • the processing procedures in the downlink non-full duplex gNB scenario are the same as those in the downlink full duplex gNB scenario, including the desired signals and the selection of precoders. The only difference lies in the considered interference.
  • the gNB transmits on Band #2, whereas in the downlink full duplex gNB scenario, the gNB receives on Band #2.
  • This distinction explains why, in the downlink full duplex gNB scenario, interference occurs from another UE (UE’ ) to the target UE.
  • the gNB when the gNB is transmitting, it operates on both Band #1 and Band #2.
  • the transmission of the gNB on Band #2 interferes with the transmission from the CD to the UE. Specifically, there is a transmission from the CD to the UE, while the gNB transmits on Band #2 to potentially another UE, creating interference with the signal to the target UE.
  • interference factors such as CLI and CCI may be considered or may not be considered in the selection process.
  • Proposal 1 involves performing this operation without selecting a precoder P at the CD and without considering CLI.
  • Proposals 2 and 3 involve selecting P at the CD, with the distinction that: Proposal 2 assumes no direct communication or control channel between the CD and the UE for reporting the choice of P, requiring the selection to be routed through the gNB, while Proposal 3 assumes a direct communication channel between the CD and the UE, allowing the UE to report its preferred P directly to the CD, bypassing the gNB.
  • Proposals 4, 5, and 6 correspond to Proposals 1, 2, and 3, respectively, but with the consideration of CLI.
  • Proposals 1 to 7 may be applicable to two cases: when the gNB operates in sub-band full duplex mode (or full duplex, as in Scenario a. 1) and when the gNB is not full duplex (HD gNB, as in Scenario a. 2) .
  • Option 1 The processes involved in Proposal 7 follow Option 1. awith CLI H cli ⁇ ibe at UE and H cli ′ at UE’ .
  • the precoder P needs to be selected through Option 1, which involves UE measurement and feedback.
  • the process begins with the gNB transmitting CSI-RS to measure H 2 .
  • the CD then performs cycling through N precoders, where for each precoder P (1) , P (2) , through P (N) , the CSI-RS is used to measure H s P (1) H 1 , H s P (2) H 1 , through H s P (N) H 1 respectively.
  • the UE provides CSI feedback to the gNB.
  • the UE decides the preferred precoder P (k * ) and reports the corresponding index jointly with the precoder pair [P 1 P 2 ] .
  • the UE may first decide P and then determine [P 1 P 2 ] . This selection is based on CSI-RS measurements and the estimated covariance matrix of Therefore, the feedback includes PMI k * for precoder P and PMI feedback for the precoder pair [P 1 P 2 ] .
  • the gNB After the gNB receives the CSI feedback from the UE, which includes the preferred precoder P (k * ) and the recommended precoders P 1 and P 2 , the gNB sends a downlink indication to the CD specifying the selected precoder P (j) that the CD should use for its transmission.
  • the selection of P (j) by the gNB may differ from the UE’s recommendation P (k * ) as the gNB must consider feedback from multiple UEs, including UE’ , to balance overall system performance.
  • both the direct signal received on Band #1 and the relayed signal received on Band #2 utilize Demodulation Reference Signals (DM-RS) to detect the transmitted messages.
  • DM-RS Demodulation Reference Signals
  • the UE implements a robust receiver design based on the estimated covariance matrix of the combined noise and interference terms
  • This robust receiver employs interference rejection techniques to suppress both the cross-link interference H cli ⁇ ibe on Band #1 and the co-channel interference H cci X o_gnb on Band #2, thereby enhancing the reception quality of the desired signals.
  • UE’ In parallel with the target UE’s measurement process, UE’ also participates in the precoder selection by listening to the CSI-RS transmissions. UE’ measures the potential interference it would cause to the target UE for each of the N candidate precoders being cycled by the CD. Specifically, UE’ measures the interference channel H cli ′P (1) H 1 when the CD applies the first precoder P (1) , measures H cli ′P (2) H 1 when the CD applies the second precoder P (2) , and continues this process through all N precoders, measuring H cl ′P (N) H 1 for the final precoder in the codebook. These measurements enable UE’ to evaluate how each CD precoder would affect the interference level it causes to the target UE’s reception on Band #2.
  • UE’ recommends preferred P (i) (and report corresponding index) based on CSI-RS and estimated covariance matrix of M o_UE′ +H cli ′PH 1 X+H cli ′PN b . Hence recommended PMI i feedback for P.
  • UE’ builds Robust RX based on estimated covariance matrix of M o_UE +H cli ′PH 1 X+H cli ′PN b .
  • Option 1. b with CLI H cli ⁇ ibe at UE and H cli ′at UE’ , makes less sense if UE’is expected to share recommendation P with CD, as a communication channel is required to be established between them. A central node needs to decide on P because UE and UE’ requests will be different. Therefore, Option 1. a may be optimal.
  • the gNB serves as the central decision node in Option 1. a, receiving precoder recommendations from both the target UE (which seeks to maximize its desired signal) and UE’ (which seeks to minimize interference it causes) .
  • the gNB must balance these potentially conflicting objectives when selecting the final precoder P (j) for the CD. This decision may prioritize the target UE’s performance while ensuring that the interference to other UEs remains within acceptable limits.
  • Proposal 7 extends the framework to handle intra-carrier intra-cell CLI, its practical implementation may be complex due to the need for coordination between multiple UEs. The procedures remain similar to Proposals 4-6, with the primary distinction being the type and source of interference being managed.
  • FIG. 32 illustrates a flow chart 3200 of a first example of a process for CSI and PMI signaling based on UE measurement and feedback. This process involves interactions between a network (NW) and a UE (e.g., the UE 104) through a base station (e.g., the base station 102) .
  • NW network
  • UE e.g., the UE 104
  • base station e.g., the base station 102
  • the UE receives a first Channel State Information Reference Signal (CSI-RS) directly from a base station on a first frequency band.
  • CSI-RS Channel State Information Reference Signal
  • the UE receives a second CSI-RS from a collaborative device (CD) on a second frequency band.
  • the second CSI-RS is a frequency-translated version of a CSI-RS transmitted by the base station to the CD on the first frequency band.
  • the UE measures a direct channel (H 2 ) between the base station and the UE based on the first CSI-RS.
  • the UE measures a cascaded channel (H s ⁇ H 1 ) between the base station and the UE through the CD based on the second CSI-RS.
  • H 1 represents a channel from the base station to the CD
  • H s represents a channel from the CD to the UE.
  • the UE Following the measurements of the direct and cascaded channels, at block 3210, the UE generates Channel State Information (CSI) feedback based on the measured direct channel and the measured cascaded channel.
  • the CSI feedback includes at least a first Precoding Matrix Indicator (PMI) for a first precoder (P 1 ) to be applied by the base station for transmission to the CD and a second PMI for a second precoder (P 2 ) to be applied by the base station for direct transmission to the UE.
  • PMI Precoding Matrix Indicator
  • the UE transmits the CSI feedback to the base station.
  • the CD may operate without applying a CD-specific precoder during the frequency translation, such that an effective precoder P at the CD equals an identity matrix.
  • the UE may further include: receiving first Demodulation Reference Signals (DM-RS) directly from the base station on the first frequency band, the first DM-RS being precoded by the second precoder (P 2 ) ; receiving second DM-RS from the CD on the second frequency band, the second DM-RS being a frequency-translated version of DM-RS transmitted by the base station to the CD and precoded by the first precoder (P 1 ) ; and demodulating data streams based on the received first DM-RS and second DM-RS.
  • DM-RS Demodulation Reference Signals
  • the CSI feedback may further include at least one of a Rank Indicator (RI) or a Channel Quality Indicator (CQI) .
  • RI Rank Indicator
  • CQI Channel Quality Indicator
  • the CD may perform an amplify-and-forward operation with frequency translation.
  • a processing delay at the CD may be maintained below a cyclic prefix duration.
  • the first frequency band may provide wide-area coverage and the second frequency band provides limited geographical coverage.
  • the first frequency band and the second frequency band may be different carriers within a same frequency band for intra-band multicarrier operation.
  • FIG. 33 illustrates a flow chart 3300 of a second example of a process for CSI and PMI signaling based on UE measurement and feedback. This process involves interactions between a network (NW) and a UE (e.g., the UE 104) through a base station (e.g., the base station 102) .
  • NW network
  • UE e.g., the UE 104
  • base station e.g., the base station 102
  • the UE receives a first Channel State Information Reference Signal (CSI-RS) directly from a base station on a first frequency band.
  • CSI-RS Channel State Information Reference Signal
  • the UE receives a plurality of N precoded CSI-RS instances from a collaborative device (CD) on a second frequency band.
  • the UE measures a direct channel (H 2 ) between the base station and the UE based on the first CSI-RS.
  • the UE measures N instances of a precoded cascaded channel (H s ⁇ P(k) ⁇ H 1 ) based on the N precoded CSI-RS instances.
  • H 1 represents a channel from the base station to the CD and H s represents a channel from the CD to the UE.
  • the UE selects an optimal CD-specific precoder P (k * ) from the N candidate precoders based on the measured direct channel and the N instances of the precoded cascaded channel.
  • the UE generates Channel State Information (CSI) feedback including an indication of the selected optimal CD-specific precoder P (k * ) , a first Precoding Matrix Indicator (PMI) for a first precoder (P 1 ) to be applied by the base station for transmission to the CD, and a second PMI for a second precoder (P 2 ) to be applied by the base station for direct transmission to the UE.
  • CSI Channel State Information
  • the UE transmits the CSI feedback to the base station.
  • the base station may transmit a downlink control indication to the CD instructing the CD to use the selected optimal CD-specific precoder P (k * ) for subsequent data transmissions.
  • the CD may store the CSI-RS received from the base station and sequentially apply the N candidate precoders to the stored CSI-RS for generating the N precoded CSI-RS instances.
  • selecting the optimal CD-specific precoder and generating the CSI feedback may further include: estimating a covariance matrix of noise and interference; and jointly optimizing the selection of the optimal CD-specific precoder P (k * ) and the first and second precoders (P 1 , P 2 ) based on the estimated covariance matrix.
  • the interference may include Cross-Link Interference (CLI) from the CD’s transmission on the second frequency band to the UE’s reception on the first frequency band.
  • CLI Cross-Link Interference
  • the CLI may be represented by H cli ⁇ ibe, where H cli is an interference channel and ibe is a function of a signal received at the CD, the CD-specific precoder, a frequency offset between the first and second frequency bands, and a modulation scheme.
  • the base station may operate in a full duplex mode, and the estimated covariance matrix may further include interference from another UE transmitting on the second frequency band, represented by H cli ′ ⁇ ue′.
  • the base station may operate in a non-full duplex mode and transmits on the second frequency band
  • the estimated covariance matrix may further include Co-Channel Interference (CCI) from the base station’s transmission on the second frequency band, represented by H cci ⁇ X o_gnb .
  • CCI Co-Channel Interference
  • the base station may transmit data streams to the UE using a third precoder (P 3 ) on the second frequency band.
  • the process may further include accounting for the CCI from the third precoder in precoder selection.
  • the UE may further include: implementing a robust receiver using interference rejection combining based on the estimated covariance matrix of noise and interference during data demodulation.
  • the base station may transmit data streams to the UE using a third precoder (P 3 ) on the second frequency band.
  • the process may further include accounting for the CCI from the third precoder in precoder selection.
  • FIG. 34 illustrates a flow chart 3400 of a third example of a process for CSI and PMI signaling based on UE measurement and feedback. This process involves interactions between a network (NW) and a UE (e.g., the UE 104) through a base station (e.g., the base station 102) .
  • NW network
  • UE e.g., the UE 104
  • base station e.g., the base station 102
  • the UE receives a first Channel State Information Reference Signal (CSI-RS) directly from a base station on a first frequency band.
  • CSI-RS Channel State Information Reference Signal
  • the UE receives a plurality of N precoded CSI-RS instances from a collaborative device (CD) on a second frequency band.
  • CD collaborative device
  • the UE measures a direct channel and N instances of a precoded cascaded channel based on the received CSI-RS instances.
  • the UE selects an optimal CD-specific precoder from N candidate precoders.
  • the UE generates a first feedback part for the base station including a first Precoding Matrix Indicator (PMI) for a first precoder to be applied by the base station for transmission to the CD and a second PMI for a second precoder to be applied by the base station for direct transmission to the UE.
  • PMI Precoding Matrix Indicator
  • the UE generates a second feedback part for the CD including an indication of the selected optimal CD-specific precoder.
  • the UE transmits the first feedback part to the base station.
  • the UE transmits the second feedback part directly to the CD via a communication channel established between the UE and the CD.
  • the UE may jointly optimize the selection of the optimal CD-specific precoder and the first and second precoders based on maximizing an effective channel capacity across both the first frequency band and the second frequency band.
  • FIG. 35 illustrates a flow chart 3500 of a fourth example of a process for CSI and PMI signaling based on UE measurement and feedback. This process involves interactions between a network (NW) and a UE (e.g., the UE 104) through a base station (e.g., the base station 102) .
  • NW network
  • UE e.g., the UE 104
  • base station e.g., the base station 102
  • the UE listens to N precoded Channel State Information Reference Signal (CSI-RS) instances transmitted by a collaborative device (CD) on a second frequency band.
  • CSI-RS Channel State Information Reference Signal
  • CD collaborative device
  • the UE determines a recommended CD-specific precoder index based on minimizing interference to the UE.
  • the UE transmits the recommended CD-specific precoder index to the base station.
  • the UE implements a robust receiver based on an estimated covariance matrix of interference for subsequent data reception.
  • the base station may determine a final CD-specific precoder based on CSI feedback from the other UE and the recommended CD-specific precoder index from the UE.
  • Combinations such as “at least one of A, B, or C, ” “one or more of A, B, or C, ” “at least one of A, B, and C, ” “one or more of A, B, and C, ” and “A, B, C, or any combination thereof” include any combination of A, B, and/or C, and may include multiples of A, multiples of B, or multiples of C.
  • combinations such as “at least one of A, B, or C, ” “one or more of A, B, or C, ” “at least one of A, B, and C, ” “one or more of A, B, and C, ” and “A, B, C, or any combination thereof” may be A only, B only, C only, A and B, A and C, B and C, or A and B and C, where any such combinations may contain one or more member or members of A, B, or C.

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Abstract

Selon un aspect de la divulgation, un procédé, un support lisible par ordinateur, et un appareil sont proposés. L'appareil peut être un UE. L'UE reçoit un premier CSI-RS directement d'une station de base sur une première bande de fréquences, et reçoit un second CSI-RS en provenance d'un dispositif collaboratif (CD) sur une seconde bande de fréquences. Le second CSI-RS est une version traduite en fréquence d'un CSI-RS transmis au CD sur la première bande de fréquences. L'UE mesure un canal direct sur la base du premier CSI-RS. L'UE mesure un canal en cascade sur la base du second CSI-RS. L'UE génère une rétroaction de CSI sur la base des canaux directs et en cascade mesurés. La rétroaction de CSI comprend au moins un premier PMI pour un premier précodeur pour une transmission au CD et un second PMI pour un second précodeur pour une transmission directe à l'UE. L'UE transmet la rétroaction de CSI à la station de base.
PCT/CN2025/101956 2024-07-04 2025-06-19 Cadre de signalisation de csi et de pmi de communication de dispositif à dispositif en duplex intégral basé sur une mesure et une rétroaction d'ue Pending WO2026007704A1 (fr)

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