WO2022055196A1 - Procédé et dispositif de précodage faisant appel à une pluralité d'antennes dans un système de communication sans fil - Google Patents

Procédé et dispositif de précodage faisant appel à une pluralité d'antennes dans un système de communication sans fil Download PDF

Info

Publication number
WO2022055196A1
WO2022055196A1 PCT/KR2021/012013 KR2021012013W WO2022055196A1 WO 2022055196 A1 WO2022055196 A1 WO 2022055196A1 KR 2021012013 W KR2021012013 W KR 2021012013W WO 2022055196 A1 WO2022055196 A1 WO 2022055196A1
Authority
WO
WIPO (PCT)
Prior art keywords
tps
group
present disclosure
terminal
cpu
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.)
Ceased
Application number
PCT/KR2021/012013
Other languages
English (en)
Korean (ko)
Inventor
이승현
한민식
강충구
이재원
이효진
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.)
Samsung Electronics Co Ltd
Korea University Research and Business Foundation
Original Assignee
Samsung Electronics Co Ltd
Korea University Research and Business Foundation
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Samsung Electronics Co Ltd, Korea University Research and Business Foundation filed Critical Samsung Electronics Co Ltd
Priority to KR1020227044528A priority Critical patent/KR20230066275A/ko
Publication of WO2022055196A1 publication Critical patent/WO2022055196A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

Links

Images

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
    • H04B7/022—Site diversity; Macro-diversity
    • H04B7/024—Co-operative use of antennas of several sites, e.g. in co-ordinated multipoint or co-operative multiple-input multiple-output [MIMO] systems
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B17/00—Monitoring; Testing
    • H04B17/30—Monitoring; Testing of propagation channels
    • H04B17/382—Monitoring; Testing of propagation channels for resource allocation, admission control or handover
    • 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
    • H04B7/04—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas
    • H04B7/06—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station
    • 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
    • H04B7/06—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station
    • H04B7/0613—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station using simultaneous transmission
    • H04B7/0615—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station using simultaneous transmission of weighted versions of same signal
    • H04B7/0619—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station using simultaneous transmission of weighted versions of same signal using feedback from receiving side
    • H04B7/0621—Feedback content
    • H04B7/0626—Channel coefficients, e.g. channel state information [CSI]
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L5/00—Arrangements affording multiple use of the transmission path
    • H04L5/003—Arrangements for allocating sub-channels of the transmission path
    • H04L5/0048—Allocation of pilot signals, i.e. of signals known to the receiver
    • H04L5/0051—Allocation of pilot signals, i.e. of signals known to the receiver of dedicated pilots, i.e. pilots destined for a single user or terminal
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W72/00—Local resource management
    • H04W72/12—Wireless traffic scheduling
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W36/00—Hand-off or reselection arrangements
    • H04W36/08—Reselecting an access point

Definitions

  • the present disclosure relates to a wireless communication system, and more particularly, in a communication system considering function split into a central unit (CU) and a distributed unit (DU), a data transmission/reception path between the CU and the DU
  • the present invention relates to a precoding method in consideration of a load of a fronthaul and a computational complexity of a CU for controlling a DU, and an apparatus capable of performing the same.
  • 5G 5th -generation
  • connected devices which are on an explosive increase, will be connected to the communication network.
  • things connected to the network include vehicles, robots, drones, home appliances, displays, smart sensors installed in various infrastructures, construction machines, and factory equipment.
  • Mobile devices are expected to evolve into various form factors such as augmented reality glasses, virtual reality headsets, and hologram devices.
  • 6G (6th -gerneration ) era efforts are being made to develop an improved 6G communication system to provide various services by connecting hundreds of billions of devices and things. For this reason, the 6G communication system is called a system after 5G communication (Beyond 5G).
  • the maximum transmission speed is tera (ie, 1,000 gigabytes) bps
  • the wireless latency is 100 microseconds ( ⁇ sec). That is, the transmission speed in the 6G communication system is 50 times faster than in the 5G communication system, and the wireless delay time is reduced by one-tenth.
  • terahertz bands such as the 95 gigahertz (95 GHz) to 3 terahertz (3 THz) bands.
  • mmWave millimeter wave
  • next-generation distributed computing technology that realizes services of exceeding complexity by utilizing ultra-high-performance communication and computing resources (mobile edge computing (MEC), cloud, etc.) is being developed.
  • MEC mobile edge computing
  • the next hyper-connected experience (the next hyper-connected) through the hyper-connectivity of the 6G communication system, which includes not only the connection between objects but also the connection between people and objects. experience) is expected to become possible.
  • the 6G communication system is expected to provide services such as true immersive extended reality (XR), high-fidelity mobile hologram, and digital replica.
  • services such as remote surgery, industrial automation, and emergency response through security and reliability enhancement are provided through the 6G communication system, so it is applied in various fields such as industry, medical care, automobiles, and home appliances.
  • the CoMP method is a method in which a plurality of TPs (transmission points) cooperate to transmit and receive data with at least one UE.
  • the CoMP method Accordingly, when uplink data or downlink data is transmitted/received between the UE and a plurality of TPs, problems such as an increase in computational complexity of the CPU and an increase in the load on the front haul, which is a data transmission/reception path between the CPU and the TPs, may occur. Therefore, it is necessary to devise a precoding method capable of solving such a problem and a system structure to which the method can be applied.
  • a method of a network entity in a communication system is provided.
  • the method of the network entity is for adjusting a ratio between a plurality of first transmission points (TPs) included in a first group serving at least one terminal and a plurality of second TPs included in a second group.
  • TPs first transmission points
  • determining whether to perform scheduling When it is determined to perform the scheduling, it is determined whether to convert at least one second TP among the plurality of second TPs in the second group to a first TP based on information associated with the at least one terminal to do; transmitting an indicator instructing to operate as the first TP to the at least one second TP when it is determined to switch the at least one second TP to the first TP;
  • precoding of the signal is performed by the network entity, and when operating as a second TP, precoding of the signal is performed by the second TP.
  • a network entity of a communication system determines whether to perform scheduling for adjusting a ratio between a plurality of first TPs included in a first group and a plurality of second TPs included in a second group serving the transceiver and at least one terminal, , whether to convert at least one second TP among the plurality of second TPs in the second group to a first TP based on information associated with the at least one terminal when determining to perform the scheduling and, when it is determined to switch the at least one second TP to the first TP, a control unit configured to transmit an indicator instructing the at least one second TP to operate as the first TP through the transceiver and, when operating as a first TP, precoding is performed on the signal in the network entity, and when operating as a second TP, precoding is performed on the signal in the second TP.
  • a precoding method is provided in consideration of the computational complexity allowed for the CPU controlling the plurality of TPs and the capacity of the front haul, which is a signal transmission/reception path between the CPU and the TPs. .
  • the UE may have optimal data transmission/reception performance.
  • FIG. 1 is a diagram illustrating a structure of a cellular mobile communication system to which the present disclosure can be applied.
  • LTE long term evolution
  • FIG. 3 is a diagram illustrating a radio protocol structure in a 3GPP standard LTE system to which the present disclosure can be applied.
  • FIG. 4 is a diagram illustrating a system structure of a 3GPP standard next-generation mobile communication to which the present disclosure can be applied.
  • FIG. 5 is a diagram illustrating a radio protocol structure in a 3GPP standard next-generation mobile communication system to which the present disclosure can be applied.
  • FIG. 6 is a diagram illustrating a structure of a system to which a non-coordinated multi point (non-CoMP) scheme is applied according to an embodiment of the present disclosure.
  • FIG. 7 is a diagram illustrating a structure of a system to which a coordinated multi point (CoMP) scheme is applied according to an embodiment of the present disclosure.
  • CoMP coordinated multi point
  • FIG. 8 is a diagram illustrating the classification of CoMP schemes in an LTE system or a next-generation mobile communication system to which the present disclosure can be applied.
  • CJT coherent joint transmission
  • NCJT non-coherent joint transmission
  • FIG. 10 is a diagram illustrating a distributed antenna system in which the CJT scheme of CoMP according to an embodiment of the present disclosure can be implemented.
  • FIG 11 is a diagram illustrating an example of a common public radio interface (CPRI) between a remote radio header (RRH) (or radio unit (RU)) and a base band unit (BBU) according to an embodiment of the present disclosure.
  • CPRI common public radio interface
  • FIG. 12 is a diagram illustrating a model of a cell-free massive MIMO-based system to which the present disclosure can be applied.
  • FIG. 13 is a diagram illustrating an order in which a CPU performs complexity-shared scheduling (CSS) according to an embodiment of the present disclosure.
  • FIG. 14 is a diagram illustrating a location of a function separation point according to an embodiment of the present disclosure.
  • 15A is a diagram illustrating a system structure in which uplink data is transmitted/received between a TP instructed to operate as a Central TP or a Local TP and a UE according to a CSS execution result according to an embodiment of the present disclosure.
  • FIG. 15B is a diagram illustrating a system structure in which a TP instructed to operate as a Central TP or a Local TP and a UE transmit and receive downlink data according to a CSS execution result according to an embodiment of the present disclosure.
  • 16 is a diagram illustrating a downlink data transmission/reception procedure when multiple demodulation-reference signals (DM-RSs) are allocated to a Central TP and a Local TP determined according to a CSS execution result according to an embodiment of the present disclosure.
  • DM-RSs demodulation-reference signals
  • FIG. 17 is a diagram illustrating a sequence in which a UE operates depending on whether a coherent joint reception indicator (CJRI) is received according to an embodiment of the present disclosure.
  • CJRI coherent joint reception indicator
  • FIG. 18 is a diagram illustrating an example of a CSS algorithm that may be executed in a CPU according to an embodiment of the present disclosure.
  • FIG. 19 is a diagram illustrating a CSS framework based on a TP embedding enhanced CPRI (eCPRI) according to an embodiment of the present disclosure.
  • eCPRI enhanced CPRI
  • 20 is a diagram illustrating a result of evaluating a user average yield while increasing a ratio of a central TP when supporting two UEs per TP when an embodiment of the present disclosure is applied.
  • 21 is a diagram illustrating a result of evaluating a user average yield while increasing a ratio of a central TP when four UEs per TP are supported when an embodiment of the present disclosure is applied.
  • FIG. 22 is a diagram illustrating a result of evaluating a lower performance 10% user yield while increasing a central TP ratio when supporting two UEs per TP when an embodiment of the present disclosure is applied.
  • FIG. 23 is a diagram illustrating a result of evaluating a lower performance 10% user yield while increasing a ratio of a central TP when supporting 4 UEs per TP when an embodiment of the present disclosure is applied.
  • 24 is a diagram illustrating a result of evaluating a yield of 10% lower performance users while increasing a ratio of a central TP when supporting two UEs per TP when an embodiment of the present disclosure is applied.
  • 25 is a diagram illustrating a result of evaluating a yield of 10% lower performance users while increasing a ratio of a central TP when supporting 4 UEs per TP when an embodiment of the present disclosure is applied.
  • 26 is a diagram illustrating a result of comparing the bit error performance of a user according to the presence or absence of channel correlation between groups determined by performing CSS when one or two DM-RSs are used when an embodiment of the present disclosure is applied. .
  • FIG. 27 is a diagram illustrating a structure of a UE to which an embodiment of the present disclosure can be applied.
  • FIG. 28 is a diagram illustrating a structure of a TP to which an embodiment of the present disclosure can be applied.
  • 29 is a diagram illustrating a structure of a network entity to which an embodiment of the present disclosure can be applied.
  • each block of the flowchart diagrams and combinations of the flowchart diagrams may be performed by computer program instructions.
  • These computer program instructions may be embodied in a processor of a general purpose computer, special purpose computer, or other programmable data processing equipment, such that the instructions performed by the processor of the computer or other programmable data processing equipment are not described in the flowchart block(s). It creates a means to perform functions.
  • These computer program instructions may also be stored in a computer-usable or computer-readable memory that may direct a computer or other programmable data processing equipment to implement a function in a particular manner, and thus the computer-usable or computer-readable memory.
  • the instructions stored in the flow chart block(s) produce an article of manufacture containing instruction means for performing the function described in the flowchart block(s).
  • the computer program instructions may also be mounted on a computer or other programmable data processing equipment, such that a series of operational steps are performed on the computer or other programmable data processing equipment to create a computer-executed process to create a computer or other programmable data processing equipment. It is also possible that instructions for performing the processing equipment provide steps for performing the functions described in the flowchart block(s).
  • each block may represent a module, segment, or portion of code that includes one or more executable instructions for executing specified logical function(s). It should also be noted that in some alternative implementations it is also possible for the functions recited in blocks to occur out of order. For example, two blocks shown one after another may be performed substantially simultaneously, or the blocks may sometimes be performed in the reverse order according to a corresponding function.
  • ' ⁇ unit' used in the present disclosure means software or hardware components such as FPGA or ASIC, and ' ⁇ unit' performs certain roles.
  • '-part' is not limited to software or hardware.
  • ' ⁇ ' may be configured to reside on an addressable storage medium or may be configured to refresh one or more processors. Accordingly, as an example, ' ⁇ ' indicates components such as software components, object-oriented software components, class components, and task components, and processes, functions, properties, and procedures. , subroutines, segments of program code, drivers, firmware, microcode, circuitry, data, databases, data structures, tables, arrays, and variables.
  • components and ' ⁇ units' may be combined into a smaller number of components and ' ⁇ units' or further separated into additional components and ' ⁇ units'.
  • components and ' ⁇ units' may be implemented to play one or more CPUs in a device or secure multimedia card.
  • 3GPP 3rd generation partnership project
  • a UE may be referred to as a terminal, a mobile station, or a wireless transmit/receive unit (WTRU), but is not limited thereto, and may be referred to by terms having the same or similar meaning.
  • WTRU wireless transmit/receive unit
  • a TP transmission point
  • TRP transmission reception point
  • AP access point
  • RU radio unit
  • DU distributed unit
  • a central processing unit may be referred to as a separate entity or a network entity that performs an operation proposed in the present disclosure.
  • various types of base stations may be referred to as CPUs regardless of their names.
  • the CPU may be referred to as a central unit (CU) according to an embodiment of the present disclosure, and is not limited thereto, and may be referred to by terms having the same or similar meaning.
  • data described in the present disclosure may be referred to as a data stream or a signal, may also be referred to as a signal transferring control information, but is not limited thereto, and terms having the same or similar meaning may be referred to by
  • precoding may refer to an operation of multiplying a modulated transmission signal by a precoder (or a precoding vector, a beamforming weight).
  • precoding may refer to an operation of changing an amplitude and a phase of a complex symbol by multiplying a complex symbol by a precoder after layer mapping.
  • FIG. 1 is a diagram illustrating a structure of a cellular mobile communication system to which the present disclosure can be applied.
  • the mobile communication system shown in FIG. 1 includes a first cell 100 , a second cell 110 , and a third cell 120 , and A TP (herein, it may mean a base station) for performing (or providing) mobile communication within each cell may be disposed in the center.
  • the first cell 100 includes a TP 130 , a first UE 140 , and a second UE 150 .
  • the TP 130 may provide a mobile communication service to the two UEs 140 and 150 located in the first cell 100 .
  • the first UE 140 receiving the mobile communication service through the TP 130 has a relatively long distance to the TP 130 compared to the second UE 150 . Accordingly, the data transmission/reception performance that may be supported by the first UE 140 may be relatively lower than the data transmission/reception performance that may be supported by the second UE 150 .
  • a reference signal may be transmitted to measure a downlink channel state of each cell or to estimate a downlink channel.
  • the reference signal may also be referred to as a pilot.
  • the reference signal transmitted by the TP to the UE includes a CSI-RS channel status information-reference signal and a demodulation-reference signal (DM-RS).
  • the UE may measure the channel state between the TP and the UE by using the CSI-RS, and may feed back channel state information.
  • the UE may estimate a downlink channel by using the DM-RS and perform demodulation of resources allocated to it based on the estimated channel.
  • FIG. 2 is a diagram illustrating a structure of an LTE system of the 3GPP standard to which an embodiment of the present disclosure can be applied.
  • the radio access network of the LTE system is a next-generation base station (evloved node B, hereinafter eNB, Node B, or base station, where eNB may refer to a TP according to the present disclosure) (2-05 , 2-10, 2-15, 2-20), MME (2-25, mobility management entity) and S-GW (2-30, serving-gateway).
  • eNB next-generation base station
  • MME mobility management entity
  • S-GW serving-gateway
  • the eNBs 2-05 - 2-20 correspond to the existing Node B of the UMTS system.
  • the eNB is connected to the UE 2-35 through a radio channel, and performs a more complex role than the existing Node B.
  • all user traffic including real-time services such as voice over IP (VoIP) through the Internet protocol, are serviced through a shared channel, so status information such as buffer status, available transmission power status, and channel status of UEs
  • VoIP voice over IP
  • a device for scheduling is required, and the eNB (2-05 - 2-20) is responsible for this.
  • One eNB typically controls multiple cells.
  • the LTE system uses, for example, orthogonal frequency division multiplexing (OFDM) in a 20Mhz bandwidth as a radio access technology.
  • OFDM orthogonal frequency division multiplexing
  • AMC adaptive modulation & coding
  • the S-GW (2-30) is a device that provides a data bearer, and creates or removes a data bearer under the control of the MME (2-25).
  • the MME is a device in charge of various control functions as well as the mobility management function for the UE, and is connected to a number of base stations.
  • FIG. 3 is a diagram illustrating a radio protocol structure in a 3GPP standard LTE system to which the present disclosure can be applied.
  • the radio protocols of the LTE system are packet data convergence protocols 3-05 and 3-40 (PDCP), radio link control 3-10, 3-35 (RLC), and medium access (MAC) in the UE and the eNB, respectively. control 3-15, 3-30).
  • PDCP packet data convergence protocols 3-05 and 3-40
  • RLC radio link control
  • MAC medium access
  • the PDCPs 3-05 and 3-40 are in charge of operations such as IP header compression/restore.
  • the main functions of PDCP are summarized below.
  • Timer-based SDU discard function timer-based SDU discard in uplink
  • the radio link control (hereinafter referred to as RLC) 3-10 and 3-35 reconfigures a PDCP packet data unit (PDU) to an appropriate size to perform ARQ operation and the like.
  • RLC radio link control
  • PDU packet data unit
  • RLC SDU discard function (RLC SDU discard (only for UM and AM data transfer)
  • the MACs 3-15 and 3-30 are connected to several RLC layer devices configured in one terminal, and perform operations of multiplexing RLC PDUs into MAC PDUs and demultiplexing RLC PDUs from MAC PDUs.
  • the main functions of MAC are summarized below.
  • the physical layer (3-20, 3-25) channel-codes and modulates upper layer data, creates an OFDM symbol and transmits it over a radio channel, or demodulates and channel-decodes an OFDM symbol received through the radio channel and transmits it to a higher layer do the action
  • FIG. 4 is a diagram illustrating a structure of a next-generation mobile communication system according to the 3GPP standard to which the present disclosure can be applied.
  • the radio access network of the next-generation mobile communication system is a next-generation base station (New Radio Node B, hereinafter NR gNB or NR base station, where NR gNB may refer to a TP according to the present disclosure). (4-10) and NR CN (4-05, New Radio Core Network).
  • UE New Radio User Equipment, hereinafter NR UE or terminal 4-15 accesses an external network through NR gNB 4-10 and NR CN 4-05.
  • the NR gNBs 4-10 correspond to an Evolved Node B (eNB) of the existing LTE system.
  • the NR gNB is connected to the NR UE 4-15 through a radio channel and can provide a service superior to that of the existing Node B.
  • eNB Evolved Node B
  • the NR gNB is connected to the NR UE 4-15 through a radio channel and can provide a service superior to that of the existing Node B.
  • a device for scheduling by collecting status information such as buffer status, available transmission power status, and channel status of UEs is required. (4-10) is in charge.
  • One NR gNB typically controls multiple cells.
  • NR CN (4-05) performs functions such as mobility support, bearer setup, QoS setup, and the like.
  • NR CN is a device in charge of various control functions as well as mobility management functions for the terminal and is connected to a number of base stations.
  • the next-generation mobile communication system can be linked with the existing LTE system, and the NR CN is connected to the MME (4-25) through a network interface.
  • the MME is connected to the existing base station eNB (4-30).
  • FIG. 5 is a diagram illustrating a radio protocol structure in a 3GPP standard next-generation mobile communication system to which the present disclosure can be applied.
  • the radio protocols of the next-generation mobile communication system are NR SDAP (5-01, 5-45), NR PDCP (5-05, 5-40), and NR RLC (5-10) in the terminal and the NR base station, respectively. , 5-35), and NR MAC (5-15, 5-30).
  • the main functions of the NR SDAPs 5-01 and 5-45 may include some of the following functions.
  • the UE can receive a configuration of whether to use the SDAP layer device header or the function of the SDAP layer device for each PDCP layer device, for each bearer, or for each logical channel in an RRC message, and the SDAP header If is set, the UE uses the uplink and downlink QoS flow and data bearer mapping information with the NAS QoS reflection setting 1-bit indicator (NAS reflective QoS) and the AS QoS reflection setting 1-bit indicator (AS reflective QoS) of the SDAP header. can be instructed to update or reset
  • the SDAP header may include QoS flow ID information indicating QoS.
  • the QoS information may be used as data processing priority and scheduling information to support a smooth service.
  • the main function of the NR PDCP (5-05, 5-40) may include some of the following functions.
  • the reordering function of the NR PDCP device refers to a function of reordering PDCP PDUs received from a lower layer in order based on a PDCP sequence number (SN), and a function of delivering data to the upper layer in the reordered order may include, or may include a function of directly delivering without considering the order, may include a function of reordering the order to record the lost PDCP PDUs, and report the status of the lost PDCP PDUs It may include a function for the transmitting side, and may include a function for requesting retransmission for lost PDCP PDUs.
  • SN PDCP sequence number
  • the main function of the NR RLC (5-10, 5-35) may include some of the following functions.
  • in-sequence delivery of the NR RLC device refers to a function of sequentially delivering RLC SDUs received from a lower layer to an upper layer, and one RLC SDU is originally divided into several RLC SDUs and received , it may include a function of reassembling and delivering it, and may include a function of rearranging the received RLC PDUs based on an RLC sequence number (SN) or PDCP SN (sequence number), and rearranging the order May include a function of recording the lost RLC PDUs, may include a function of reporting a status on the lost RLC PDUs to the transmitting side, and may include a function of requesting retransmission of the lost RLC PDUs.
  • SN RLC sequence number
  • PDCP SN sequence number
  • the timer It may include a function of sequentially delivering all RLC SDUs received before the start of RLC to the upper layer, or if a predetermined timer expires even if there are lost RLC SDUs, all RLC SDUs received so far are sequentially transferred to the upper layer. It may include a function to transmit.
  • the RLC PDUs may be processed in the order in which they are received (in the order of arrival regardless of the sequence number and sequence number) and delivered to the PDCP device out of sequence (out-of sequence delivery). Segments stored in the buffer or to be received later are received, reconstructed into one complete RLC PDU, processed and delivered to the PDCP device.
  • the NR RLC layer may not include a concatenation function, and the function may be performed by the NR MAC layer or replaced with a multiplexing function of the NR MAC layer.
  • the out-of-sequence delivery function of the NR RLC device refers to a function of directly delivering RLC SDUs received from a lower layer to a higher layer regardless of order, and one RLC SDU originally has several RLCs.
  • it may include a function of reassembling it and delivering it, and it may include a function of storing the RLC SN or PDCP SN of the received RLC PDUs, arranging the order, and recording the lost RLC PDUs.
  • the NR MACs 5-15 and 5-30 may be connected to several NR RLC layer devices configured in one terminal, and the main function of the NR MAC may include some of the following functions.
  • the NR PHY layer (5-20, 5-25) channel-codes and modulates upper layer data, creates an OFDM symbol and transmits it over a radio channel, or demodulates and channel-decodes an OFDM symbol received through the radio channel to an upper layer. You can perform a forwarding action.
  • non-CoMP non-coordinated multi point
  • FIG. 6 is a diagram illustrating a structure of a system to which a non-coordinated multi point (non-CoMP) scheme is applied according to an embodiment of the present disclosure.
  • a mobile communication system including three cells and a TP disposed in the center of each cell is exemplified as an example.
  • the TP of each cell may transmit data to the UE existing in the cell. That is, the TP of Cell 0 may transmit data 600 to UE0 existing in the service area of Cell 0.
  • the TP of Cell 1 transmits data 610 to UE1 existing in the service area of Cell 1
  • the TP of Cell 2 is the Cell Data 620 may be transmitted to UE2 existing in the service area of 2.
  • the radio resource 630 used in Cell the radio resource 650 used in Cell 1
  • the radio resource 640 used in Cell 2 Cell 0 to Cell 2 use different time and frequency resources. This indicates that data can be transmitted.
  • a transmission scheme in which the TPs of each cell transmit data only to the UE in the corresponding cell using different time and frequency resources, and there is no cooperation between the TPs may be referred to as a non-CoMP scheme.
  • FIG. 7 is a diagram illustrating a structure of a system to which a coordinated multi point (CoMP) scheme is applied according to an embodiment of the present disclosure.
  • CoMP coordinated multi point
  • FIG. 7 the system structure to which the CoMP method in which data transmission/reception is performed in the presence of cooperation between TPs is applied. shown.
  • the UE receives data transmitted through a physical downlink shared channel (PDSCH) in Cell 0 and Cell 2 . That is, the UE simultaneously receives data 700 and 710 transmitted from two TPs.
  • PDSCH physical downlink shared channel
  • one or more TPs cooperate to perform the same data transmission for one UE, so that a UE located relatively far from the TP (eg, a cell boundary) is more improved It is now possible to support data transmission/reception performance.
  • the CoMP scheme for providing a more improved service to a user at a cell boundary may be implemented in various ways in a communication system, and will be described below with reference to FIG. 8 .
  • FIG. 8 is a diagram illustrating a classification of a CoMP scheme in an LTE system or a next-generation mobile communication system to which an embodiment of the present disclosure can be applied.
  • the CoMP scheme is an uplink CoMP scheme for improving uplink data transmission/reception performance, which is a wireless connection from a UE to a TP, and a downlink method for improving downlink data transmission/reception performance, which is a wireless connection from a TP to the UE. It can be classified according to the CoMP method.
  • the uplink CoMP scheme may be implemented as joint reception (JR), coordinated scheduling (CS), or a combination of the above schemes.
  • JR is a method of receiving data transmitted from a terminal together at multiple TPs.
  • CS is a method in which a plurality of TPs cooperate with each other to perform scheduling and precoding.
  • the downlink CoMP scheme may be implemented by joint processing (JP) and coordinated scheduling/coordinated beamforming (CS/CB), or a combination of the above schemes.
  • JP joint processing
  • CS/CB coordinated scheduling/coordinated beamforming
  • one TP transmits data to the UE, but a plurality of TPs cooperate to perform scheduling and beamforming. Through this, interference to the UE located at the boundary of the TP can be reduced.
  • the JP is in which a plurality of TPs share data to be transmitted to the UE, and may be further classified into dynamic point selection (DPS) and joint transmission (JT).
  • DPS may refer to dynamic cell selection (DCS), in which one TP among a plurality of TPs transmits downlink data to the UE, but the TP transmitting data to the UE is dynamically changed. That is, it means a method in which downlink data is transmitted through a TP selected according to a specific rule among a plurality of TPs.
  • JT is a method in which several TPs cooperate to transmit the same data to the UE.
  • JT can be divided into CJT (coherent JT) and NCJT (non-coherent JT) again depending on whether TPs transmit data streams in synchronization.
  • CJT coherent JT
  • NCJT non-coherent JT
  • CJT coherent joint transmission
  • NCJT non-coherent joint transmission
  • FIG. 9A shows a system for transmitting data to the UE according to the CJT scheme
  • FIG. 9B shows a system for transmitting data to the UE according to the NCJT scheme.
  • a central processing unit performs centralized scheduling (which may be referred to as central scheduling), and the TPs controlled by the CPU are synchronized according to the scheduling, and the UE to transmit data (coherent transmission).
  • each TP independently schedules (which may be referred to as local scheduling), does not synchronize with other TPs, and independently transmits data to the UE (non-coherent transmission) .
  • a plurality of TPs transmit a data stream that is time synchronized by compensating for a delay to the UE, respectively, and the UE transmits from the plurality of TPs.
  • the reception performance of the UE can be improved accordingly.
  • interference by cells belonging to other users can be reduced in a system where multiple users exist through cooperation between a plurality of TPs, and the throughput and data reception performance of the UE at the cell boundary can be increased. .
  • the CJT method of CoMP considered by the present disclosure may be implemented in a communication system based on a distributed antenna system including a plurality of TPs and a CPU connected to the plurality of TPs through a front hole.
  • the CPU may transmit/receive data to and from a plurality of TPs through the front hall, and may control the TPs.
  • FIG. 10 A more detailed description will be given with reference to FIG. 10 .
  • FIG. 10 is a diagram illustrating a distributed antenna system in which the CJT scheme of CoMP according to an embodiment of the present disclosure can be implemented.
  • the embodiment of the present disclosure is not limited thereto, and the JR scheme may be implemented in the distributed antenna system of FIG. 10 .
  • a distributed antenna system including one cell 1000 is illustrated as an example.
  • a DU (as described above, a DU of the present disclosure may refer to the above-described TP) and a CU connected through a front hole (as described above, a CU of the present disclosure may refer to the above-described CPU) (1030) ) may be disposed in the center of the cell 1000 , and the DUs 1060 , 1070 , 1080 , and 1090 may be disposed at different positions within each cell.
  • the CU 1030 controls the DUs 1060, 1070, 1080, and 1090 in the cell, and each DU may transmit a downlink signal to the UE located in the cell 1000 under the control of the CU 1030 ( JT).
  • each of the DUs 1060 , 1070 , 1080 and 1090 may include one or a plurality of antennas.
  • downlink data can be coherently transmitted to the UE through beamforming using an antenna located in the TP (CJT).
  • the CPU may generate a centralized precoder (or may refer to an operation of acquiring or confirming the precoder), and may apply it to data to be transmitted to the UE.
  • the CPU transmits the precoder-applied data to each TP connected to the CPU through a front haul, and each TP may synchronize and transmit a data stream to the UE (coherent transmission).
  • FIG. 11 illustrates a common public radio interface (CPRI) between a remote radio header (RRH) (or radio unit (RU), DU) and a base band unit (BBU) (or CU) according to an embodiment of the present disclosure. It is a drawing showing an example.
  • CPRI common public radio interface
  • CPRI CPRI standard
  • a function may be separated into a CU and a DU based on option 8 shown in FIG. 11 , and CPRI may be used as a communication interface between the CU and the DU.
  • CPRI may be used as a communication interface between the CU and the DU.
  • the functions are separated based on option 8 as described above, only the RF stage exists in the DU, and the remaining signal processing-related operations can be performed by the CU.
  • the CU when transmitting downlink data, the CU must sample an RF signal and transmit it to the DU through the front haul, which causes a large load on the front haul.
  • an enhanced common public radio interface (eCPRI) standard was defined in order to solve the aforementioned fronthaul limitation, so that functions can be separated by selecting another option.
  • functions may be divided into CUs and DUs based on option 2 or option 7 shown in FIG. 11 . If the function is separated in the upper layer as in option 2, since precoding must be performed distributedly in the DU, the effect of improving data transmission/reception performance obtained through the CJT method may be reduced. On the other hand, if the function is separated from the lower layer as in option 7, the transmission amount of the front haul may still be excessive compared to the existing one. That is, a trade-off between CJT performance and fronthaul transmission may occur depending on the function separation point. In this regard, there is a limit to implementing the CJT method through eCPRI.
  • the CPU needs to know exactly the channel to generate the precoder matrix for CJT.
  • the number of UEs is greater than the number of TPs
  • the overhead due to channel estimation is not large, but in an ultra-dense network (UDN) environment in which the number of UEs is greater than the number of TPs, a separate downlink pilot is provided for each TP. Since channel estimation must be performed using the method, there may be a problem in that overhead due to channel estimation may greatly increase.
  • UDN ultra-dense network
  • each UE cannot accurately feed back channel information, or, in general, quantizes channel information to perform channel quality information (CQI), precoding matrix indicator (PMI), Feedback is provided in the form of a rank indicator (RI) or the like.
  • CQI channel quality information
  • PMI precoding matrix indicator
  • RI rank indicator
  • a cell-free massive MIMO-based system distributed MIMO, or distributed antenna system, etc.
  • a cell-free massive MIMO-based system which is a system structure with a large number of TPs supporting one terminal. This has been suggested. A detailed description of the cell-free massive MIMO-based system will be described with reference to FIG. 12 .
  • FIG. 12 is a diagram illustrating a model of a cell-free massive MIMO-based system to which the present disclosure can be applied.
  • the cell-free massive MIMO-based system may estimate a downlink channel based on an uplink pilot by operating with time division duplexing (TDD). That is, unlike the downlink channel estimated based on the downlink pilot transmitted from the TP to the UE, the downlink channel may be estimated based on the uplink pilot transmitted from the UE to the TP.
  • the TP 1210 may generate channel information for the terminal based on the uplink pilot received from the UE 1220 and transmit the channel information to the CPU 1200 .
  • the CPU 1200 may perform precoding for controlling multi-user interference based on the channel information. Accordingly, the TP 1210 coherently transmits data to the UE 1220, so that the CJT method of CoMP considered by the present disclosure can be implemented.
  • the number of TPs that need to cooperate with each other increases significantly compared to the existing system. Therefore, in implementing the CJT method in the cell-free massive MIMO system, the computational complexity required to control numerous TPs in the CPU A problem may arise in that it increases significantly.
  • the CPU of a cell-free massive MIMO-based system must precisely synchronize data transmission and reception between numerous TPs, and since many TPs cooperate dynamically, the precoder generation process (or precoding process) taking these cooperative TPs into consideration
  • the computational complexity of the CPU can be very high.
  • there is a limitation in that the load of data or channel information transmitted through the front hole is still large. Therefore, even in a cell-free massive MIMO-based system, there may be problems in implementing the CJT method of CoMP.
  • the present disclosure proposes a method to solve the problem of high computational complexity of the CPU and the load of the front hall that may occur in implementing the CoMP CJT method in a cell-free massive MIMO-based wireless communication system.
  • a plurality of TPs controlled by the CPU are divided into a Central TP group in which precoding is centrally performed in the CPU and a Local TP group in which precoding is performed in each TP distributedly, and the Central TP or
  • a system structure in which uplink data or downlink data transmission/reception can be performed between a plurality of TPs and a UE is proposed.
  • scheduling may be performed to determine whether a TP operates as a Central TP or a Local TP based on a given fronthaul capacity and computational complexity according to UE and network performance.
  • the scheduling that determines the operation method of the TP may be referred to as CSS (complexity-shared scheduling).
  • CSS may mean dividing (determining or classifying) a plurality of TPs to perform either an operation performed by the Central TP group or an operation performed by the Local TP group.
  • CSS may refer to a process of classifying all TPs into a Central TP group and a Local TP group or a process of determining a ratio of the Central TP group and the Local TP group among all TPs. Also, since it is determined whether precoding is performed in the CPU (Central TP) or the TP (Local TP) according to the CSS execution result, CSS may refer to a precoding method. Meanwhile, in the present disclosure, for convenience of description, the Central TP group may be referred to as a first group and the Local TP group may be referred to as a second group.
  • the yield (throughput) of is the amount of calculation to be performed in each TP unit, denotes the amount of information to be transmitted on the front haul link.
  • the yield (throughput) of is the amount of calculation to be performed in each TP unit, denotes the amount of information to be transmitted on the front haul link.
  • two situations can be assumed: when all TPs operate centrally (ie, Central TP) or when they operate distributedly (ie, Local TP). If all TPs operate as Central TPs, the amount of information to be transmitted through the front haul link ( ) and total computation ( ) will be limited. On the other hand, when all TPs are local TPs, reception performance may be deteriorated due to high interference between TPs.
  • the CPU is TP groups that support (eg, ) to the Central TP group (for example, ) and the Local TP group (eg, ) can be classified (or divided, divided).
  • the amount of information to be transmitted through the front haul link ( ) is the number of antennas (eg, ) and symbol size (e.g., ), and it can be determined based on the quantization level ( Q) .
  • the CPU determines whether each TP operates as a Central TP or a Local TP so as to optimize the performance given by the objective function in the given constraint. Specific details of performing the CSS in the CPU will be described with reference to FIG. 13 .
  • FIG. 13 is a diagram illustrating a sequence in which a CPU performs CSS according to an embodiment of the present disclosure.
  • the CPU may check whether CSS for determining whether TPs controlled by the CPU operate as a Central TP or a Local TP is performed.
  • the CPU may check whether CSS is executed based on at least one of several criteria.
  • the CPU may receive a report of channel information for a channel between the TP and the UE, and may check whether to perform CSS based on the channel information and various criteria.
  • the CPU may initiate CSS in the following cases.
  • the following conditions are only an example of the present disclosure, and the scope of the present disclosure is not limited thereto.
  • CSS is first performed when clustering (which may mean determining a set of TPs to serve the UE) is performed, or CSS is performed at every arbitrary cycle can be
  • CSS may be performed with a shorter cycle than the large-scale coherence time.
  • clustering is performed every large-scale coherence time period, which is a longer period than CSS, or is performed when a handover of the terminal occurs.
  • CSS is performed more frequently than clustering, but CSS is a procedure that consumes less cost than clustering that requires complex procedures. It has the advantage of optimizing the performance of
  • the UE reports its downlink throughput information or its own channel reception status (RSRP) to the CPU through uplink, and the CPU can know the uplink and/or downlink throughput of the UE through this.
  • RSRP channel reception status
  • the CPU may perform CSS.
  • the UE may request the CPU to perform CSS.
  • the UE checks its downlink throughput or channel status, and when the UE's throughput or channel status falls below a certain threshold, it can request the CPU to perform CSS so that the UE can further allocate a Central TP. there is.
  • the CPU converts the TPs to a Central TP based on at least one of a front hall capacity and a computational complexity allowable by the CPU. Alternatively, it may be determined to operate as a Local TP.
  • the CPU preferentially operates as a Central TP for TPs supporting a UE with low yield (it may refer to throughput) in order to maximize performance for cell-edge users through CSS. can do it That is, the CPU assigns at least one TP group supporting the UE to a group of Local TPs ( ), the Central TP's group ( ), the set of Central TPs ( ), you can perform CSS so that more TPs belong to it.
  • the CPU may increase the ratio of Central TPs among TPs supporting UEs.
  • the CPU can allocate the computational resources of the UE already having good enough reception performance to lower users (that is, the CPU is the Central TP of the UE having sufficiently good reception performance).
  • the TP can be operated as a Local TP, and the Local TP of the UE, which is a lower performance, can be operated as a Central TP).
  • CSS may be performed by reflecting this.
  • embodiments of the present disclosure are not limited to the above-described examples, and the CPU may perform CSS based on various criteria so as to maximize the reception performance of the UE.
  • the CPU may transmit a CSS execution result (eg, an indicator instructing to operate as a Central TP or a Local TP) to TPs that have been CSS execution targets in steps 13 to 300 .
  • TPs receiving the CSS execution result may operate as a Central TP or a Local TP according to the CSS result.
  • CSS may be implemented through TPs having eCPRI embedded in FIG. 14 .
  • the TP that was instructed to operate as a Local TP is instructed by the CPU to operate as a Central TP according to the CSS execution result, or the TP that was instructed to operate as an existing Central TP is expected to act as a Local TP according to the CSS execution result.
  • CSS execution target TPs should be able to freely select split 1 or split 2 shown in FIG. 14 . That is, when layer splitting occurs in split 1 or split 2, all procedures for split 1 or split 2 may be embedded in TP so that the TP can perform all necessary procedures according to the T-selected split.
  • the precoding procedure is performed in a distributed unit (DU)
  • layer splitting is performed in split 1
  • the DU may be referred to as a local TP.
  • the precoding procedure is performed in a central unit (CU)
  • layer splitting is performed in split 2
  • the DU may be referred to as a Central TP.
  • the present disclosure provides a system in which a Local TP that distributes precoding in DUs (or RUs) and a Central TP that centrally performs precoding in CUs coexist can be applied to As described above, the Central TP or the TP corresponding to the Local TP may be changed to operate as the Local TP or the Central TP as needed. That is, according to an embodiment of the present disclosure, for each TP, it may be determined whether precoding is performed in the TP distributedly or in a CU that centrally controls the TP.
  • the CoMP data transmission/reception system may be implemented based on TPs in which the CPU is instructed to operate as a Central TP or a Local TP according to a CSS execution result.
  • TPs in which the CPU is instructed to operate as a Central TP or a Local TP according to a CSS execution result.
  • FIGS. 15A and 15B for a more detailed description, reference will be made to FIGS. 15A and 15B .
  • 15A and 15B are diagrams illustrating a system structure in which a TP instructed to operate as a Central TP or a Local TP transmits/receives uplink data and downlink data according to a CSS execution result according to an embodiment of the present disclosure; .
  • FIGS. 15A and 15B the following assumptions may be applied for convenience of description.
  • each TP is antennas are mounted, and the TPs are connected to the CPU through a front hole.
  • the number of TPs is greater than the number of UEs
  • the number of TPs ( L) is greater than the number of UEs ( K) .
  • Each UE is equipped with one antenna, and the channel between the UE and the TP has a Rayleigh fading distribution.
  • the channel between the second terminals is a vector
  • the spatial correlation between the antennas of the TP for each UE is the correlation matrix
  • a large-scale fading coefficient representing the path loss and shadowing of the channel was defined as
  • the 15A illustrates a system structure in which the UE transmits/receives uplink data to/from the CPU through a Central TP and a Local TP serving the UE as a result of performing CSS according to an embodiment of the present disclosure.
  • the Central TP estimates the channel based on the uplink pilot received from the UE, and transmits information on the estimated channel to the CPU. Thereafter, the CPU calculates a central combining vector based on the estimated channel, and estimates the signal by applying the combining vector to a signal transmitted from the UE.
  • the local TP estimates a channel based on an uplink pilot received from the UE, and calculates a local combining vector based on the estimated channel.
  • the Local TP estimates a symbol by applying a joint vector to the signal transmitted from the UE, and sends the estimated symbol to the CPU, and the CPU combines them to estimate the signal transmitted from the UE.
  • the JR method considered by the present disclosure can be implemented.
  • the terminal has an arbitrary number (eg, orthogonality) with each other during the coherence time period. ) can be transmitted, and the uplink pilot can be expressed by the following [Equation 3].
  • each uplink pilot has an arbitrary length (eg, ) can have any length. At this time, am.
  • Uplink pilots are allocated to each UE, and since the number of UEs is generally greater than the number of uplink pilots, one pilot may be allocated to multiple UEs.
  • the Central TP or Local TP After receiving the uplink pilot from the UE, the Central TP or Local TP sends a channel between the UE and the TP ( ) can be estimated. In this case, the channel estimation may be performed based on, for example, minimum mean square error (MMSE) zero-forcing (ZF) or least square (LS Square).
  • MMSE minimum mean square error
  • ZF zero-forcing
  • LS Square least square
  • Channel estimation value between UE and TP the estimate of the channel between the UE and all TPs can be expressed by the following [Equation 4].
  • the uplink data reception signal may be expressed by the following [Equation 5].
  • the received uplink signal is combined with L TPs, in which case the combining vector (eg, ) is multiplied by a weight and combined for all TPs to estimate uplink data, which can be expressed by [Equation 6] as follows.
  • the binding vector for each TP may be calculated based on MR or MMSE.
  • It can be expressed as , and may be applied to estimating a symbol in each TP.
  • the centralized MMSE combining vector central combining vector
  • the above-described method is a method for estimating by centrally combining received signals in the CPU.
  • a method of estimating the symbols of the second UE collecting them in the CPU and combining them may be considered.
  • the symbol estimated at the th TP it can be estimated by combining the received signals based on the following [Equation 8].
  • LSFD large-scale fading decoding
  • clustering may be assumed such that the TP does not support all UEs in the system, but only supports (or serves) some UEs belonging to the system.
  • UE index and TP index For , the number of antennas in the TP is when By defining a diagonal matrix consisting of a set of , it is possible to indicate which TP antenna supports which UE.
  • diagonal matrix( ) can be expressed by the following [Equation 10].
  • the second TP is a set of TPs that support If you belong to the TP An identity matrix is given to each antenna, the second TP If it does not belong to , a matrix is given in which all entries of the same size are 0. Accordingly, The clustering matrix supporting
  • Is represents an uplink transmission symbol of
  • the clustering may be defined by the following [Equation 13].
  • the UE may determine an interfering UE that strongly interferes with itself.
  • a set of UEs that interfere with is A TP serving (or supporting) may include all UEs served, and may be expressed by the following [Equation 14].
  • the conventional centralized MMSE combination vector (Equation 7) or the distributed MMSE combination vector (Equation 9) is represented by the following [Equation 15] and [Equation 16], respectively.
  • Equation 15 is called a P-MMSE (partial MMSE) combined vector
  • [Equation 16] is LP-MMSE (local partial MMSE) can be referred to as
  • the CPU may estimate the uplink data transmitted by the UE as described above based on the joint vectors according to Equations 15 and 16.
  • the Central TP in transmitting and receiving downlink data, receives data precoded by the CPU from the CPU, processes the data and transmits it to the UE, and the Local TP performs precoding on the data to be transmitted to the UE. and processes the precoded data and transmits it to the UE. Accordingly, a plurality of TPs composed of a Central TP and a Local TP can transmit downlink data to the UE, so that the CJT scheme considered by the present disclosure can be implemented.
  • the k-th reception signal of the UE in the downlink of FIG. 15B may be expressed by the following [Equation 17].
  • Is It is a downlink data signal to be transmitted to the second UE ( ), denotes a precoding vector in consideration of L TPs, respectively.
  • MR precoding may be applied to each TP as shown in Equation 18 below.
  • the power of a joint vector for uplink data may be normalized and used as a precoding vector for downlink transmission.
  • the precoding vector may be used as a centralized precoder applied by the CPU or a distributed precoder applied by the TP.
  • a vector obtained by normalizing the power of the combined vector may be used, or the combined vector may be used, and the present embodiment is not limited thereto.
  • downlink transmission data can be expressed by the following [Equation 19].
  • a precoding vector for downlink data denotes a downlink transmission symbol.
  • the clustering A set of UEs that interfere with can be defined as The set of such UEs is
  • the TP that serves may include all UEs served, and may be expressed by the following [Equation 20].
  • the power of the uplink data combining vector may be normalized and used as a normalized precoding vector for downlink transmission.
  • a unique downlink DM-RS ( ) can be assigned.
  • the UE can accurately estimate the downlink channel based on the DM-RS, and thus obtain a gain in reception performance.
  • CB conjugate beamforming
  • the th UE is an effective channel ( ), it is necessary to have sufficient information to know If you know downlink data ( ) can be reliably estimated.
  • a case in which a downlink pilot (a downlink reference signal, a DM-RS, etc. may be referred to) is transmitted through beamforming in order to estimate .
  • DM-RS Downlink Reference Signal
  • the reception procedure of the UE through one DM-RS is as follows.
  • a unique downlink DM-RS ( ) and the TP is UE-specific DM-RS ( ), and thus a signal received by the UE may be expressed by the following [Equation 25].
  • the estimated effective channel ( ) can be expressed by [Equation 27] as follows.
  • the estimated effective channel ( )Through is the downlink signal can be received coherently.
  • the downlink capacity may be calculated based on [Equation 31] as follows.
  • the correct effective channel ( ) by estimating the estimation error of the effective channel ( It can be derived that the reception performance can be improved as ) decreases.
  • a certain time e.g., time
  • [Equation 32] the signal the UE receives ( )
  • Equation 32 indicates interference by another user's DM-RS transmitted from the same DM-RS resource.
  • the received signal ( ) from each effective channel ( ) can be estimated. Then, based on the estimated effective channel, the UE determines the downlink combining vector ( ) can be created.
  • the UE receives a downlink reception signal ( ), it is possible to coherently estimate a symbol by applying a downlink combining vector and combining it. (For example, , here may mean the estimated symbol.)
  • multiple DM-RSs may be used to obtain a reception diversity gain.
  • different DM-RS resources may be allocated to the Central TP and the Local TP determined as a result of performing CSS.
  • one DM-RS may be allocated to a Central TP, and the remaining DM-RSs may be allocated to Local TPs.
  • the diversity gain can be secured only when the correlation between the effective channels of the group is low when TPs are grouped. You can select (or schedule) them.
  • class Live channel when multiple TPs allocate the same DM-RS resource to transmit a pilot to the UE as described above (that is, transmit a pilot using one DM-RS)
  • an effective channel which is the sum of transmitted channels, is estimated, there is no significant difference in reception performance compared to perfect channel state information reception (CSIR).
  • each class Live channel ( ), it is more perfect to estimate each effective channel by allocating DM-RS resources to each TP separately (for example, when precoding is performed independently or distributedly in a distributed antenna, etc.)
  • An accurate channel close to CSIR can be estimated, and a higher diversity gain can be obtained by configuring the receiving end through the more accurately estimated channel.
  • the present disclosure proposes a structure for estimating a channel close to perfect CSIR by using a plurality of DM-RSs in order to increase receive diversity performance through accurate effective channel estimation of a user.
  • the CPU allocates different DM-RS resources to the Central TP and the Local TP, respectively, and each TP transmits data to the UE based on the allocated DM-RS resource.
  • the reason for allocating DM-RS resources by dividing Central TP and Local TP in this way is that, in the case of Central TP, the channel correlation of Central TPs is reflected in the effective channel through centralized precoding. It is to allocate DM-RS that can be estimated. The remaining DM-RSs may be allocated to the Local TP, and as the number of DM-RSs increases, the UE may accurately estimate an effective channel to improve reception performance.
  • the present disclosure considers a case of applying two DM-RSs for convenience of explanation, but is not limited thereto, More DM-RSs can be used.
  • two effective channels to be estimated class There may be a low correlation between If the distributions of two effective channels are similar and thus highly correlated, the diversity gain obtained through accurate channel estimation based on multiple DM-RSs is less than when effective channels are estimated based on one DM-RS. On the other hand, if the distribution of two effective channels is different and the correlation between channels is low, the performance gain obtained by accurately estimating each channel based on two DM-RSs is large.
  • the CPU determines whether each of the TPs operates as a Central TP or a Local TP through CSS in order to obtain the diversity gain as described above, and then the Central TP and the Local TP Multiple DM-RSs can be assigned to a TP.
  • CJRI coherent joint reception indicator
  • 16 is a diagram illustrating a downlink data transmission/reception procedure when multiple DM-RSs are allocated to a Central TP and a Local TP determined according to a CSS execution result according to an embodiment of the present disclosure.
  • Some of steps, steps 16-190, steps 16-200, steps 16-210, steps 16-220, and steps 16-230 may be omitted, may be performed sequentially, or may be performed simultaneously.
  • steps 16-190, steps 16-200, steps 16-210, steps 16-220, and steps 16-230 may be omitted, may be performed sequentially, or may be performed simultaneously.
  • the UE 1220 sends an uplink pilot (uplink reference signal or SRS (sounding) reference signal) can be transmitted.
  • uplink pilot uplink reference signal or SRS (sounding) reference signal
  • the TP 1210 Upon receiving the uplink pilot from the UE, the TP 1210 generates channel information (or may be channel state information) between the UE 1220 and the TP 1210 based on the uplink pilot in steps 16-110. can do. In addition, the TP 1210 may transmit the channel information to the CPU 1200 in steps 16-120. In this case, the channel information may mean channel information (large-scale channel information) for performing clustering or CSS, rather than information on all channels to perform precoding.
  • channel information may mean channel information (large-scale channel information) for performing clustering or CSS, rather than information on all channels to perform precoding.
  • the CPU 1200 may check whether CSS is performed based on at least one of various criteria in steps 16 to 130 .
  • the CPU 1200 receives channel information from the TP 1210 and performs CSS based on the channel information and various criteria as an example, but the present disclosure is not limited thereto.
  • the CSS may be initiated by a predetermined period, a specific threshold, and a CSS execution request of the UE 1220, in this case, steps 16-100 to 16-120 may be omitted.
  • the CPU 1200 decides to perform the CSS, the CPU 1200 executes the CSS based on a preset standard (eg, it may mean a standard set by a network operator) in steps 16-140. can be done Meanwhile, in steps 16-130, the CPU 1200 may determine whether to cluster based on the channel information (or channel state information) received in steps 16-120. If it is determined to perform clustering in steps 16-130, the CPU 1200 may perform clustering in steps 16-140. At this time, when the CPU 1200 determines to perform clustering, CSS may not be performed, and the present invention is not limited thereto, and the clustering and CSS may be performed simultaneously or sequentially.
  • a preset standard eg, it may mean a standard set by a network operator
  • the CPU 1200 transmits the CSS execution result to each TP 1210 in steps 16-150.
  • the CSS execution result relates to whether each TP 1210 operates as a Central TP or as a Local TP.
  • the CPU provides the CSS execution result to each TP 1210 .
  • an indicator central/local indicator
  • the indicator may consist of 1 bit.
  • each Central TP or Local TP may be included in a Central TP group (or Central TP set) consisting of a plurality of Central TPs or a Local TP group (or a Local TP set) consisting of a plurality of Local TPs, and in this case, the CPU 1200 may instruct any one of the TPs included in the Central TP group or the Local TP group to operate as a Central TP or a Local TP.
  • the TPs of the group to which the TP instructed to operate as the Central TP or the Local TP by the CPU 1200 may operate as the Central TP or the Local TP according to the instruction (that is, the CPU is the Central TP in the TP group unit). It can also be instructed to operate as a TP or Local TP).
  • the TP 1210 may determine whether it will operate as either a Central TP or a Local TP based on the indicator. After confirming which TP it will operate with in this way, the central TP processing process (steps 16-160) or the local TP processing process (steps 16-170) as described above is performed to create a centralized precoder (central precoder). precoder) or a distributed precoder (local precoder). Since the detailed description of the processing process of each TP has been described above, it will be omitted here.
  • the CPU 1200 allocates several DM-RS resources to the Central TP and the Local TP, and the UE 1220 Signals received from each TP 1210 may be coherently combined and received based on an effective channel estimated through DM-RS.
  • the CPU 1200 determines which TPs will share a plurality of DM-RS resources to be transmitted to the UE 1220, and in steps 16-190, the CPU 1200 determines the DM-RS of the DM-RS. Allocation information may be transmitted to a Central TP (or may be a set or a group made of Central TPs) and a Local TP (or may be a set or a group made of Local TPs) 1210 , respectively. Meanwhile, in steps 16-180, the CPU 1200 may allocate a DM-RS resource so that the Central TP shares one DM-RS resource. That is, in this case, the Central TP may be characterized in sharing the same DM-RS resource.
  • the TP (which may be any one of a Central TP, a Local TP, or both), which has received the information on the DM-RS assignment from the CPU 1200 , 1210 receives data in steps 16-200 Information on allocation of DM-RS may be transmitted to the UE 1220 to be used.
  • the TP (which may be either a Central TP or a Local TP) 1210 coherently receives a data stream transmitted to the UE 1220 corresponding to a plurality of DM-RSs in steps 16-210. It may transmit an indicator (coherent joint reception indicator, CJRI) (or coherent reception indicator, may be referred to as CRI) indicating that.
  • CJRI coherent joint reception indicator
  • the UE 1220 when a data stream precoded with the same precoder as the DM-RS each allocated to a plurality of TPs is transmitted from each of the plurality of TPs 1210 to the UE 1220, the UE 1220 may be configured prior to or at the same time.
  • An indicator eg, CJRI described above instructing to coherently receive the data stream may be received.
  • Local TP operates in a non-coherent joint transmission (NCJT) method for non-coherent transmission. That is, it is common for local TPs to transmit data by performing independent scheduling (local scheduling) without synchronizing transmission with the cooperative TPs.
  • the Local TP may transmit data coherently in synchronization with cooperative TPs such as the Central TP in steps 16-220.
  • the Local TP may select either non-coherent data transmission or coherent data transmission, and may indicate this to the UE 1220 through CJRI.
  • the UE 1220 may receive data coherent or non-coherent according to a method in which the TP 1210 transmits data (coherent transmission or non-coherent transmission). Accordingly, the operation of the UE 1220 may vary depending on whether the UE 1220 has received the CJRI from the TP, which will be described with reference to FIG. 17 .
  • 17 is a diagram illustrating a sequence in which a UE operates depending on whether CJRI is received according to an embodiment of the present disclosure.
  • steps 17-100 of FIG. 17 if the UE receives CJRI from the TP, this means that the cooperative TPs synchronize and transmit a data stream to the UE, so that the UE transmits a data stream to the UE in steps 16-230
  • the data stream transmitted from each of the TP and the local TP can be coherently received.
  • the Local TP since the resource allocation information of the Local TP can be checked through the resource allocation information of the Central TP, the Local TP does not need to inform the UE of additional resource allocation indication information through downlink control information (DCI).
  • DCI downlink control information
  • an operation may be performed differently depending on whether the DM-RS is shared between the Local TP and the Central TP.
  • steps 17-110 if the Local TP shares DM-RS with the Central TP (this may mean that the DM-RS port is shared or the UE is allocated only one DM-RS port), In steps 17-130, the UE estimates a channel through one DM-RS, and generates a reception filter through the estimated channel. Thereafter, by receiving one DCI (which may mean DCI transmitted from a central TP), the location of a resource allocated to the DCI is confirmed through the DCI, and data can be received.
  • DCI which may mean DCI transmitted from a central TP
  • steps 17-110 if the Local TP does not share the DM-RS with the Central TP (when the DM-RS ports are used independently, or the UE is assigned two or more DM-RS ports, case), in steps 17-140, the UE estimates one channel based on a plurality of DM-RSs allocated to it, and generates a reception filter through the estimated channels. Thereafter, one DCI among DCIs transmitted from multiple TPs may be received, a location of a resource allocated to itself may be confirmed based on the received DCI, and data may be received.
  • the UE performs non-coherent reception-combination with respect to the non-coherent transmitted data stream. That is, the UE estimates a channel based on the DM-RS transmitted from each TP for demodulation in steps 17-120, and each TP is independently transmitted to the UE based on DCI transmitted independently by each TP. After identifying one's own resource locations, the corresponding location may be demodulated based on a channel estimated through the DM-RS of the corresponding TP.
  • steps 17-100, 17-110, 17-120, 17-130, and 17-140 of FIG. 17 may be omitted, may be sequentially performed, or may be performed simultaneously .
  • CSS performed to obtain optimal data transmission/reception performance may be implemented in the form of various algorithms, which will be described with reference to FIG. 18 .
  • FIG. 18 is a diagram illustrating an example of a CSS algorithm that may be executed in a CPU according to an embodiment of the present disclosure.
  • the CPU determines whether to perform CSS based on at least one of several criteria. For example, as described above, when a CSS cycle is set, the CPU may periodically perform CSS based on the cycle, or may determine whether to perform CSS based on a certain criterion such as a threshold, Alternatively, when receiving a request to perform CSS from the UE, it may be determined whether to perform CSS.
  • step 18-100 when the CPU determines not to perform CSS, data transmission/reception may be performed based on the existing Central TP or Local TP. Meanwhile, if it is decided to perform CSS, steps 18-110 are performed. At this time, the CPU has the available front hall capacity (eg, ) and computational complexity (e.g., ), taking into account the total number of Central TPs supported by the CPU (for example, ) can be calculated.
  • the CPU may identify a UE that satisfies a predetermined condition based on throughput information for each of the at least one UE.
  • the CPU is a set of TPs serving the identified UE ( )can confirm.
  • the CPU has the lowest yield (throughput value) based on the throughput information.
  • the CPU identifies UEs corresponding to a predetermined number or a number determined according to a predetermined condition or a number calculated by the CPU in order from the lowest UE to the lowest yield, and a set of TPs serving the identified UEs. can confirm.
  • the number calculated by the CPU is, for example, the number calculated in steps 18-100. can mean
  • the CPU determines the set of TPs ( ), all TPs belonging to Local TPs can be converted to Central TPs.
  • all of the TPs corresponding to the Local TPs may be converted to the Central TPs, but the present invention is not limited thereto, and at least one of the Local TPs may be converted into the Central TPs.
  • the conversion of the TP corresponding to the Local TP to the Central TP may mean that the Local TP is changed to a group to which the Central TP belongs.
  • the conversion of a TP corresponding to the Local TP to the Central TP may mean instructing the Local TP to perform an operation performed by the Central TP.
  • the example of converting a Local TP to a Central TP is exemplified, but the present invention is not limited thereto, and the CPU uses a set of TPs ( ), it is also possible to convert the TP corresponding to the Central TP to the Local TP.
  • steps 18-120 may mean an operation in which the CPU adjusts the ratio of the Central TP and the Local TP in the TP set identified in steps 18-110.
  • the CPU instructs or converts the existing Central TP to operate as a Local TP as described above in steps 18-120, or converts the existing Local TP to a Central TP
  • the ratio between the Central TP and the Local TP in the TP set can be adjusted.
  • the ratio between the Central TP and the Local TP may be determined based on at least one of calculation complexity and fronthaul capacity.
  • the CPU may check whether the CSS is terminated.
  • the CPU can check whether CSS is terminated based on various criteria. For example, if the number of Central TPs is the total number of supportable Central TPs calculated in steps 18-110 ( ), it is possible to return to steps 18-110 again. On the other hand, if the number of Central TPs If equal to or greater than , the CPU may terminate CSS execution.
  • steps 18-100, 18-110, 18-120, and 18-130 of FIG. 18 may be omitted, may be sequentially performed, or may be performed simultaneously.
  • FIG. 19 is a diagram illustrating a CSS framework based on a TP embedding eCPRI according to an embodiment of the present disclosure.
  • each TP can perform all procedures corresponding to different layer splitting, and by performing different procedures according to the CSS execution result, optimal data transmission/reception performance is achieved in the constraint of CPU calculation amount and fronthaul usage. can be obtained
  • 20 and 21 are diagrams illustrating the yield of all users when an embodiment of the present disclosure is applied.
  • 20 and 21 show the total user yield in CDF when 2 UEs or 4 UEs are supported per TP in a system having 100 TPs and 20 UEs, respectively.
  • the solid line is the case when MMSE considering interference from all users is performed, and the dotted lines are the precoder that only considers the interference of UEs belonging to its own cluster (or the TP set to which it belongs) using TP clustering. How to create and send.
  • the leftmost dotted line graph is the L-MMSE performance using a distributed scalable MMSE precoder
  • the right dotted line graph is the P-MMSE performance using the centralized scalable MMSE precoder.
  • the middle graph shows the CDF by centrally transforming the random TP generation. In both FIGS.
  • 22 and 23 are diagrams illustrating the performance of the lower 10% of users when an embodiment of the present disclosure is applied.
  • 22 and 23 show the performance of the lower 10% users when supporting 2 UEs or 4 UEs per TP in a system having 100 TPs and 20 UEs, respectively, as shown in FIGS. 20 and 21 .
  • the performance of the lower 10% users can be improved by 2 times or 2.5 times in each embodiment through the control of the centralized or distributed precoder generation method of the TP.
  • all TPs have to operate only with distributed precoders in consideration of the constraints according to the load of the front hall, whereas by applying the CSS structure of the present disclosure to control the TP precoder generation method according to the capacity constraints of the front hall, the lower 10 % Users' performance has been improved by up to 2x to 2.5x.
  • 24 and 25 are diagrams illustrating the performance of the lower 10% of users when an embodiment of the present disclosure is applied.
  • 24 and 25 are diagrams illustrating results of evaluating the yield of the lower 10% users when supporting 2 UEs and 4 UEs per TP, respectively, in a system having 100 TPs and 20 UEs.
  • the average number of TPs serving the UE is 10
  • the average number of TPs serving the UE is 20 .
  • the Distributed-MMSE Clustering graph shows the performance of the L-MMSE scheme in which all TPs are local TPs, and a distributed scalable MMSE precoder is used for the UE it serves.
  • the Partial_MMSE:Clustering graph shows the performance of the P-MMSE method using a centralized scalable MMSE precoder as a Central TP where all TPs have performed clustering.
  • the Multicell-MMSE: Full Clustering graph shows the theoretical maximum performance when all TPs are Central TPs and service all UEs.
  • the Hybrid-MMSE Clustering+Random CSS graph in FIGS. 24 and 25 shows the yield of the lower 10% users while arbitrarily changing the TP to the Central TP (Random CSS).
  • the Hybrid-MMSE Clustering+Random CSS graph in FIGS. 24 and 25, it can be seen that the performance is traded off as the percentage of the Central TP varies from 0% to 100%.
  • Hybrid-MMSE Clustering+Greedy CSS graph in FIGS. 24 and 25, unlike the above-described Random CSS, preemptively converts a TP serving a UE of lower performance to a Central TP (Greedy CSS)
  • a Central TP Central TP
  • 26 is a diagram illustrating a result of comparing a user's bit error performance according to the presence or absence of channel correlation between TP groups determined by performing CSS when one or two DM-RSs are used when an embodiment of the present disclosure is applied; am.
  • FIG. 27 is a diagram illustrating a structure of a UE to which an embodiment of the present disclosure can be applied.
  • the UE may include a transceiver 2710 , a controller 2720 , and a memory 2730 .
  • the controller may be defined as a circuit or an application-specific integrated circuit or at least one processor.
  • the transceiver 2710 may transmit/receive a signal.
  • the transceiver 2710 may receive, for example, a data stream (or data, signal) transmitted from a Central TP and a Local TP.
  • the controller 2720 may control the overall operation of the UE according to an embodiment proposed in the present disclosure.
  • the controller 2720 may control the signal flow between blocks to perform an operation according to the above-described drawing (or flowchart, flowchart).
  • the memory 2730 may store at least one of information transmitted/received through the transceiver 2710 and information generated through the control unit 2720 .
  • FIG. 28 is a diagram illustrating a structure of a TP to which an embodiment of the present disclosure can be applied.
  • the TP may include a transceiver 2810 , a controller 2820 , and a memory 2830 .
  • the controller may be defined as a circuit or an application-specific integrated circuit or one processor.
  • the transceiver 2810 may include a communication unit or a network interfacing unit, and the transceiver 2810 according to an embodiment of the present disclosure is connected to the CPU through a front hall. Signals can be sent and received. In addition, the TP may transmit/receive a signal to/from the UE through the transceiver 2810 .
  • the controller 2820 may control the overall operation of the TP according to the embodiment proposed in the present disclosure.
  • the controller 2820 may control a signal flow between blocks to perform an operation according to the above-described drawing (or flowchart, flowchart).
  • the TP may be controlled to perform an operation according to the instruction.
  • the memory 2830 may store at least one of information transmitted and received through the transceiver 2810 and information generated through the control unit 2820 .
  • 29 is a diagram illustrating a structure of a network entity to which an embodiment of the present disclosure can be applied.
  • a network entity (CPU, which may refer to a central unit (CU) according to an embodiment of the present disclosure) includes a transceiver 2910 , a control unit 2920 , and a memory 2930 .
  • the controller may be defined as a circuit or an application-specific integrated circuit or one processor.
  • the transceiver 2910 may include a communication unit or a network interfacing unit, and the transceiver 2910 according to an embodiment of the present disclosure is connected to a TP through a front hole. Signals can be sent and received. In addition, it is possible to transmit and receive a signal with another network entity (eg, MME of an LTE system, a gateway, or AMF of a 5G (NR) system, SMF, etc.) through the transceiver 2910 . .
  • MME Mobility Management Entity
  • the controller 2920 may control the overall operation of the network entity according to the embodiment proposed in the present disclosure.
  • the controller 2920 may control the signal flow between blocks to perform an operation according to the above-described drawing (or flowchart, flowchart).
  • whether to perform CSS for controlling a ratio between a Central TP and a Local TP may be determined, and the network entity may be controlled so that the CSS is performed.
  • the memory 2930 may store at least one of information transmitted and received through the transceiver 2910 and information generated through the control unit 2920 .
  • a network entity may refer to an external server or an external network entity configured to control at least one TP.
  • the computational complexity allowed for the CPUs controlling the plurality of TPs and A precoding method is provided in consideration of the capacity of a front haul, which is a signal transmission/reception path between a CPU and a TP.
  • the UE may have optimal data transmission/reception performance.
  • the present disclosure has been described with reference to a communication system according to a star topology in which at least one TP (or DU) is directly connected to one CPU (or CU) through 1-hop, the present disclosure is not limited thereto.
  • the embodiments proposed in the present disclosure are also applicable to various communication systems such as a communication system in which a plurality of CUs exist, a multi-hop communication system in which DUs are connected to DUs again, or communication systems according to various topologies such as bus or mesh.

Landscapes

  • Engineering & Computer Science (AREA)
  • Signal Processing (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Mobile Radio Communication Systems (AREA)
  • Quality & Reliability (AREA)

Abstract

La présente divulgation concerne un système de communication 5G ou 6G destiné à prendre en charge un débit de transmission de données supérieur à celui d'un système de communication 4G, tel que LTE. Selon un mode de réalisation, la présente divulgation concerne un procédé d'une entité de réseau dans un système de communication sans fil. Le procédé d'une entité de réseau consiste : à déterminer s'il faut effectuer une planification de réglage du rapport entre une pluralité de premiers points de transmission (TP) inclus dans un premier groupe desservant au moins un terminal et une pluralité de seconds TP inclus dans un second groupe ; à déterminer s'il faut convertir au moins l'un des TP de la pluralité de seconds TP en un premier TP sur la base d'informations associées à un ou plusieurs terminaux, si la performance de la planification a été déterminée ; et à transmettre, au second ou aux seconds TP, un indicateur indiquant une opération avec le premier TP, si la conversion du second ou des seconds TP en premier TP a été déterminée. Si le fonctionnement se produit avec le premier TP, les signaux sont précodés dans l'entité de réseau et, si le fonctionnement se produit avec le second TP, les signaux sont précodés dans le second TP. De cette manière, un meilleur service peut être fourni dans un environnement où la complexité de calcul, qui peut être autorisée par une UC commandant de multiples TP, et la capacité fronthaul sont limitées.
PCT/KR2021/012013 2020-09-11 2021-09-06 Procédé et dispositif de précodage faisant appel à une pluralité d'antennes dans un système de communication sans fil Ceased WO2022055196A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
KR1020227044528A KR20230066275A (ko) 2020-09-11 2021-09-06 무선 통신 시스템에서 다중 안테나 기반의 프리코딩 방법 및 장치

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
KR20200116996 2020-09-11
KR10-2020-0116996 2020-09-11

Publications (1)

Publication Number Publication Date
WO2022055196A1 true WO2022055196A1 (fr) 2022-03-17

Family

ID=80632322

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/KR2021/012013 Ceased WO2022055196A1 (fr) 2020-09-11 2021-09-06 Procédé et dispositif de précodage faisant appel à une pluralité d'antennes dans un système de communication sans fil

Country Status (2)

Country Link
KR (1) KR20230066275A (fr)
WO (1) WO2022055196A1 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN116319199A (zh) * 2023-03-02 2023-06-23 华南理工大学 无线功率通信网络最大吞吐量闭式解求解方法、装置及介质

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US9225449B2 (en) * 2012-05-11 2015-12-29 Intel Corporation Performing a handover in a heterogeneous wireless network
US20160088542A1 (en) * 2014-09-24 2016-03-24 Apple Inc. Multi-RAT Radio Resource Aggregation with Split Bearer Support
WO2017177402A1 (fr) * 2016-04-13 2017-10-19 Huizhou Tcl Mobile Communication Co.,Ltd Procédés de transfert intercellulaire de communication, équipement utilisateur et stations de base
US10219259B2 (en) * 2016-05-13 2019-02-26 Qualcomm Incorporated Uplink-based cell selection
US10499297B2 (en) * 2016-07-29 2019-12-03 Huawei Technologies Co., Ltd. Method for handover between distributed access points and related device

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US9225449B2 (en) * 2012-05-11 2015-12-29 Intel Corporation Performing a handover in a heterogeneous wireless network
US20160088542A1 (en) * 2014-09-24 2016-03-24 Apple Inc. Multi-RAT Radio Resource Aggregation with Split Bearer Support
WO2017177402A1 (fr) * 2016-04-13 2017-10-19 Huizhou Tcl Mobile Communication Co.,Ltd Procédés de transfert intercellulaire de communication, équipement utilisateur et stations de base
US10219259B2 (en) * 2016-05-13 2019-02-26 Qualcomm Incorporated Uplink-based cell selection
US10499297B2 (en) * 2016-07-29 2019-12-03 Huawei Technologies Co., Ltd. Method for handover between distributed access points and related device

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN116319199A (zh) * 2023-03-02 2023-06-23 华南理工大学 无线功率通信网络最大吞吐量闭式解求解方法、装置及介质
CN116319199B (zh) * 2023-03-02 2024-05-31 华南理工大学 无线功率通信网络最大吞吐量闭式解求解方法、装置及介质

Also Published As

Publication number Publication date
KR20230066275A (ko) 2023-05-15

Similar Documents

Publication Publication Date Title
WO2021187871A1 (fr) Procédé et appareil d'optimisation et de configuration de performance basées sur la technologie o-ran
WO2021066481A1 (fr) Procédé et appareil pour prendre en charge la transmission et la réception simultanées à de multiples points de transmission et de réception dans un système de communication mobile de nouvelle génération
WO2022092992A1 (fr) Procédé et appareil de mesure de faisceau et de rapport dans un système de communication sans fil
WO2021066497A1 (fr) Procédé et appareil de multiplexage partiel de csi
WO2018117738A1 (fr) Livre de codes pour entrée multiple sortie multiple (mimo) de liaison montante pour des systèmes de communication sans fil évolués
WO2018110952A2 (fr) Appareil et procédé de commande de flux de données dans un système de communication sans fil
WO2019066560A1 (fr) Procédé de réalisation de transmission de liaison montante dans un système de communication sans fil et dispositif correspondant
WO2020111745A1 (fr) Procédé et appareil de coordination entre nœuds pour une relation de voisinage automatique
WO2023128600A1 (fr) Procédé et appareil de rapport d'informations doppler de canal variant dans le temps dans des systèmes de communication sans fil
WO2023200218A1 (fr) Sélection et rapport de sous-ensemble de trp
WO2016137061A1 (fr) Procédé de rétroaction de csi dans un système de communication sans fil, et appareil associé
WO2020009432A1 (fr) Procédé et dispositif de réalisation de formation de faisceau dans un système de communication sans fil
WO2020167076A1 (fr) Procédé permettant de générer une séquence à faible papr dans un système de communication sans fil, et appareil correspondant
WO2024010382A1 (fr) Procédé et appareil de gestion de faisceau sélectif en fréquence
WO2023013794A1 (fr) Procédé de transmission d'un signal de multiplexage par répartition orthogonale de la fréquence sur la base d'une ris dans un système de communication sans fil, et dispositif associé
WO2023211231A1 (fr) Procédé de fonctionnement de dispositif dans un système de communication sans fil et dispositif utilisant le procédé
WO2018203715A1 (fr) Procédé et dispositif d'émission/réception d'un signal de référence de démodulation d'une ev2x
WO2022055196A1 (fr) Procédé et dispositif de précodage faisant appel à une pluralité d'antennes dans un système de communication sans fil
WO2025127876A1 (fr) Procédé d'émission ou de réception de message de plan de commande par l'intermédiaire d'une interface fronthaul, et dispositif électronique pour sa mise en oeuvre
WO2024151095A1 (fr) Rapport démarré par un ue
WO2024071866A1 (fr) Procédé de transmission et de réception en liaison montante dans un système de communication sans fil, et dispositif associé
WO2022211440A1 (fr) Procédé et dispositif de transmission d'un message de recherche de relais de liaison latérale sur la base d'une priorité dans un système de communication sans fil
WO2026095108A1 (fr) Procédé d'augmentation de la capacité du canal rsma en liaison descendante grâce à l'amélioration de la similitude des canaux ris
WO2026075491A1 (fr) Transmission et multiplexage d'informations de commande ul
WO2026089485A1 (fr) Procédé et appareil de transmission en liaison montante dans un système de communication sans fil

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 21867062

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 21867062

Country of ref document: EP

Kind code of ref document: A1