WO2025252995A1 - Procédé de fonctionnement tdd efficace dans un ntn - Google Patents

Procédé de fonctionnement tdd efficace dans un ntn

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Publication number
WO2025252995A1
WO2025252995A1 PCT/EP2025/065890 EP2025065890W WO2025252995A1 WO 2025252995 A1 WO2025252995 A1 WO 2025252995A1 EP 2025065890 W EP2025065890 W EP 2025065890W WO 2025252995 A1 WO2025252995 A1 WO 2025252995A1
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WO
WIPO (PCT)
Prior art keywords
base station
slots
frame
slot
frame structure
Prior art date
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Pending
Application number
PCT/EP2025/065890
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English (en)
Inventor
Thomas Haustein
Paul Simon Holt Leather
Thomas Heyn
Rashid KHOUIL
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.)
Fraunhofer Gesellschaft zur Foerderung der Angewandten Forschung eV
Original Assignee
Fraunhofer Gesellschaft zur Foerderung der Angewandten Forschung eV
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.)
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Application filed by Fraunhofer Gesellschaft zur Foerderung der Angewandten Forschung eV filed Critical Fraunhofer Gesellschaft zur Foerderung der Angewandten Forschung eV
Publication of WO2025252995A1 publication Critical patent/WO2025252995A1/fr
Pending legal-status Critical Current
Anticipated expiration legal-status Critical

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Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W72/00—Local resource management
    • H04W72/04—Wireless resource allocation
    • H04W72/044—Wireless resource allocation based on the type of the allocated resource
    • H04W72/0446—Resources in time domain, e.g. slots or frames
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B7/00—Radio transmission systems, i.e. using radiation field
    • H04B7/14—Relay systems
    • H04B7/15—Active relay systems
    • H04B7/185—Space-based or airborne stations; Stations for satellite systems
    • H04B7/1851—Systems using a satellite or space-based relay
    • H04B7/18513—Transmission in a satellite or space-based system
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B7/00—Radio transmission systems, i.e. using radiation field
    • H04B7/14—Relay systems
    • H04B7/15—Active relay systems
    • H04B7/185—Space-based or airborne stations; Stations for satellite systems
    • H04B7/1853—Satellite systems for providing telephony service to a mobile station, i.e. mobile satellite service
    • H04B7/18539—Arrangements for managing radio, resources, i.e. for establishing or releasing a connection
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W84/00—Network topologies
    • H04W84/02—Hierarchically pre-organised networks, e.g. paging networks, cellular networks, WLAN [Wireless Local Area Network] or WLL [Wireless Local Loop]
    • H04W84/04—Large scale networks; Deep hierarchical networks
    • H04W84/06—Airborne or Satellite Networks

Definitions

  • Embodiments of the present application relate to the field of wireless communication, and more specifically, to enhancing wireless communication in the field of non-terrestrial networks, NTN. Aspects of the present invention relate to apparatus and methods for an efficient TDD operation in NTN.
  • Fig. 1 is a schematic representation of an example of a terrestrial and/or non-terrestrial wireless network 100 including, as is shown in Fig. 1(a), a core network 102 and one or more radio access networks RANi, RAN2, ... RANN.
  • Fig. 1 (b) is a schematic representation of an example of a radio access network RAN n that may include one or more base stations gNBi to gNBs, each serving a specific area surrounding the base station schematically represented by respective cells IO61 to IO65. The base stations are provided to serve users within a cell.
  • base station refers to a gNB in 5G networks, an eNB in UMTS/LTE/LTE-A/ LTE-A Pro, or just a BS in other mobile communication standards.
  • a user may be a stationary device or a mobile device.
  • the wireless communication system may also be accessed by mobile or stationary loT devices which connect to a base station or to a user.
  • the mobile devices or the loT devices may include physical devices, ground based vehicles, such as robots or cars, aerial vehicles, such as manned or unmanned aerial vehicles (UAVs), the latter also referred to as drones, buildings and other items or devices having embedded therein electronics, software, sensors, actuators, or the like as well as network connectivity that enables these devices to collect and exchange data across an existing network infrastructure.
  • ground based vehicles such as robots or cars
  • aerial vehicles such as manned or unmanned aerial vehicles (UAVs)
  • UAVs unmanned aerial vehicles
  • Fig. 1 (b) shows an exemplary view of five cells, however, the RAN n may include more or less such cells, and RAN n may also include only one base station.
  • Fig. 1 (b) shows two users UE1 and UE2, also referred to as user equipment, UE, that are in cell IO62 and that are served by base station gNB2. Another user UE3 is shown in cell IO64 which is served by base station gNB4.
  • the arrows IO81, IO82 and IO83 schematically represent uplink/downlink connections for transmitting data from a user UE1, UE2 and UE3 to the base stations gNB2, gNB4 or for transmitting data from the base stations gNB2, gNB4 to the users UE1, UE2, UE3.
  • Fig. 1 (b) shows two loT devices 110i and HO2 in cell IO64, which may be stationary or mobile devices.
  • the loT device 110i accesses the wireless communication system via the base station gNB4 to receive and transmit data as schematically represented by arrow 112i.
  • the loT device HO2 accesses the wireless communication system via the user UE3 as is schematically represented by arrow 1122.
  • the respective base station gNBi to gNBs may be connected to the core network 102, e.g., via the S1 interface, via respective backhaul links 114i to 114 5 , which are schematically represented in Fig. 1(b) by the arrows pointing to “core”.
  • the core network 102 may be connected to one or more external networks.
  • gNBi to gNB 5 may connected, e.g., via the S1 or X2 interface or the Xn interface in NR, with each other via respective backhaul links 1161 to 1165, which are schematically represented in Fig. 1 (b) by the arrows pointing to “gNBs”.
  • Embodiments described herein are not limited to terrestrial networks, TNs, but relate also to networks being implemented, at least in parts, as non-terrestrial network, NTN, as shown in Fig.
  • a satellite Si may operate, for example, to bridge communication between different base stations, to serve one or more UE and/or a cell on the ground, e.g., as a nonterrestrial base station, to communicate with a different satellite.
  • Satellites such as satellite Si and/or other types of non-terrestrial communication nodes, e.g., airplanes, balloons, high altitude platforms, HAP, may form at least a part of a non-terrestrial network that may also incorporate terrestrial nodes comprising but not limited to core network functions.
  • a non-terrestrial network may also make sure of terrestrial nodes, e.g., base stations and/or relays and/or user equipment.
  • the physical resource grid may comprise a set of resource elements to which various physical channels and physical signals are mapped.
  • the physical channels may include the physical downlink, uplink and sidelink shared channels (PDSCH, PLISCH, PSSCH) carrying user specific data, also referred to as downlink, uplink and sidelink payload data, the physical broadcast channel (PBCH) carrying for example a master information block (MIB), the physical downlink shared channel (PDSCH) carrying for example a system information block (SIB), the physical downlink, uplink and sidelink control channels (PDCCH, PLICCH, PSSCH) carrying for example the downlink control information (DCI), the uplink control information (UCI) and the sidelink control information (SCI).
  • PBCH physical broadcast channel
  • MIB master information block
  • PDSCH physical downlink shared channel
  • SIB system information block
  • PDCCH, PLICCH, PSSCH carrying for example the downlink control information (DCI), the uplink control information (UCI) and the sidelink control information (SCI).
  • DCI
  • the physical channels may further include the physical random access channel (PRACH or RACH) used by UEs for accessing the network once a UE is synchronized and has obtained the MIB and SIB.
  • the physical signals may comprise reference signals or symbols (RS), synchronization signals and the like.
  • the resource grid may comprise a frame or radio frame having a certain duration in the time domain and having a given bandwidth in the frequency domain.
  • the frame may have a certain number of subframes of a predefined length, e.g., 1ms.
  • Each subframe may include one or more slots of 12 or 14 OFDM symbols depending on the cyclic prefix (CP) length.
  • CP cyclic prefix
  • All OFDM symbols may be used for DL or UL or only a subset, e.g., when utilizing shortened transmission time intervals (sTTI) or a mini- slot/non-slot-based frame structure comprising just a few OFDM symbols.
  • sTTI shortened transmission time intervals
  • mini- slot/non-slot-based frame structure comprising just a few OFDM symbols.
  • the wireless communication system may be any single-tone or multicarrier system using frequency-division multiplexing, like the orthogonal frequency-division multiplexing (OFDM) system, the orthogonal frequency-division multiple access (OFDMA) system, or any other IFFT-based signal with or without CP, e.g., DFT-s-OFDM.
  • Other waveforms like non- orthogonal waveforms for multiple access, e.g., filter-bank multicarrier (FBMC), generalized frequency division multiplexing (GFDM) or universal filtered multi carrier (LIFMC), may be used.
  • FBMC filter-bank multicarrier
  • GFDM generalized frequency division multiplexing
  • LIFMC universal filtered multi carrier
  • the wireless communication system may operate, e.g., in accordance with the LTE-Advanced pro standard or the NR (5G), New Radio, standard.
  • the wireless network or communication system 100 depicted in Fig. 1 may by a heterogeneous network having distinct overlaid networks, e.g., a network of macro cells with each macro cell including a macro base station, like base station gNBi to gNBs, and a network of small cell base stations (not shown in Fig. 1), like femto or pico base stations.
  • a network of macro cells with each macro cell including a macro base station, like base station gNBi to gNBs, and a network of small cell base stations (not shown in Fig. 1), like femto or pico base stations.
  • non-terrestrial wireless communication networks including spaceborne transceivers, like satellites, and/or airborne transceivers, like unmanned aircraft systems.
  • the non-terrestrial wireless communication network or system may operate in a similar way as the terrestrial system described above with reference to Fig. 1 , for example in accordance with the LTE-Advanced Pro standard or the NR (5G), new radio, standard.
  • UEs that communicate directly with each other over one or more sidelink (SL) channels e.g., using the PC5 interface.
  • UEs that communicate directly with each other over the sidelink may include vehicles communicating directly with other vehicles (V2V communication), vehicles communicating with other entities of the wireless communication network (V2X communication), for example roadside entities, like traffic lights, traffic signs, or pedestrians.
  • V2V communication vehicles communicating directly with other vehicles
  • V2X communication vehicles communicating with other entities of the wireless communication network
  • Other UEs may not be vehicular related UEs and may comprise any of the above-mentioned devices.
  • Such devices may also communicate directly with each other (D2D communication) using the SL channels.
  • both UEs may be served by the same base station so that the base station may provide sidelink resource allocation configuration or assistance for the UEs.
  • both UEs may be within the coverage area of a base station, like one of the base stations depicted in Fig. 1. This is referred to as an “in-coverage” scenario.
  • Another scenario is referred to as an “out-of-coverage” scenario. It is noted that “out-of-coverage” does not mean that the two UEs are not within one of the cells depicted in Fig.
  • these UEs may not be connected to a base station, for example, they are not in an RRC connected state, so that the UEs do not receive from the base station any sidelink resource allocation configuration or assistance, and/or may be connected to the base station, but, for one or more reasons, the base station may not provide sidelink resource allocation configuration or assistance for the UEs, and/or may be connected to the base station that may not support NR V2X services, e.g., GSM, UMTS, LTE base stations.
  • NR V2X services e.g., GSM, UMTS, LTE base stations.
  • one of the UEs may also be connected with a BS, and may relay information from the BS to the other UE via the sidelink interface.
  • the relaying may be performed in the same frequency band (in-band-relay) or another frequency band (out-of-band relay) may be used.
  • communication on the Uu and on the sidelink may be decoupled using different time slots as in time division duplex, TDD, systems.
  • the base station gNB has a coverage area which, basically, corresponds to the cell schematically represented in Fig. 1.
  • the UEs directly communicating with each other may be both in the coverage area of the base station gNB.
  • Both UEs are possibly connected to the base station gNB and, in addition, they are connected directly with each other over the PC5 interface.
  • the scheduling and/or interference management of the V2V traffic is assisted by the gNB via control signalling over the Uu interface, which is the radio interface between the base station and the UEs.
  • the gNB provides SL resource allocation configuration or assistance for the UEs, and the gNB assigns the resources to be used for the V2V communication over the sidelink.
  • This configuration is also referred to as a mode 1 configuration in NR V2X or as a mode 3 configuration in LTE V2X.
  • the UEs directly communicating with each other are either not connected to a base station, although they may be physically within a cell of a wireless communication network, or some or all of the UEs directly communicating with each other are to a base station but the base station does not provide for the SL resource allocation configuration or assistance.
  • UEs may directly communicate with each other over a sidelink, e.g., using the PC5 interface.
  • the scheduling and/or interference management of the V2V traffic is based on algorithms implemented between the vehicles. This configuration is also referred to as a mode 2 configuration in NR V2X or as a mode 4 configuration in LTE V2X.
  • the out-of-coverage scenario does not necessarily mean that the respective mode 2 UEs (in NR) or mode 4 UEs (in LTE) are outside of the coverage of a base station, rather, it means that the respective mode 2 UEs (in NR) or mode 4 UEs (in LTE) are not served by a base station, are not connected to the base station of the coverage area, or are connected to the base station but receive no SL resource allocation configuration or assistance from the base station.
  • one of the UEs is covered by the gNB, i.e. connected with Uu to the gNB, wherein the second UE is not covered by the gNB and only connected via the PC5 interface to the first UE, or that the second vehicle is connected via the PC5 interface to the first vehicle UE but via Uu to another gNB.
  • Fig. 1 shows a schematic representation of an example of a wireless communication system
  • Fig. 2 is a schematic representation of a wireless communication system comprising a transceiver, like a base station or a relay, and a plurality of communication devices, like UEs, according to an embodiment
  • Fig. 3 shows a schematic diagram of UEs being located within a coverage of satellite Si; to illustrate a distance-based issue solved by embodiments described herein;
  • Fig. 4a-b show schematic illustrations of a non-terrestrial network with different path lengths between satellites and terrestrial UEs;
  • Fig. 5 shows a UE dependent/distance dependent effective TDD slot configuration according to an embodiment
  • Fig. 6 illustrates an example of a computer system on which units or modules as well as the steps of the methods described in accordance with the inventive approach may execute.
  • Embodiments of the present invention may be implemented in a wireless communication system or network as depicted in Fig. 1 including a transceiver, like a base station, gNB, or relay, and a plurality of communication devices, like user equipment’s, UEs.
  • Fig. 2 is a schematic representation of a wireless communication system comprising a transceiver 200, like a base station or a relay, and a plurality of communication devices 202i to 202n, like UEs.
  • the UEs might communicated directly with each other via a wireless communication link or channel 203, like a radio link (e.g., using the PC5 interface (sidelink)).
  • the transceiver and the UEs 202 might communicate via a wireless communication link or channel 204, like a radio link (e.g., using the llu interface).
  • the transceiver 200 might include one or more antennas ANT or an antenna array having a plurality of antenna elements, a signal processor 200a and a transceiver unit 200b.
  • the UEs 202 might include one or more antennas ANT or an antenna array having a plurality of antennas, a processor 202a 1 to 202an, and a transceiver (e.g., receiver and/or transmitter) unit 202b1 to 202bn.
  • the base station 200 and/or the one or more UEs 202 may operate in accordance with the inventive teachings described herein.
  • Embodiments are based on the recognition that there are present unpaired spectra allocated to different entities or network concepts.
  • An example thereof is Iridium when compared to 3GPP. Under periods of Iridium in 3GPP leads to an unpaired spectrum allocated to Iridium.
  • Embodiments are based on the finding that it is of advantage to use TDD for NTN to utilize such an unpaired spectrum. However, this leads to several problems to be addressed. Those problems comprise, for example:
  • Guard periods may be configured I controlled by the network to reduce impact to the UEs
  • TDD slot structure of system information block 1 , SIB1 Considering resource allocation for individual UEs and groups of UEs depending on the location of the satellite and/orTA which allows predictable more DL or UL resources to be used by UEs while the satellite flies over. o
  • signalling e.g., to create reduced interference situation at the UE in a multi-spot overlay scenario
  • Xn intersat links and bend pipe satellites with interface between ground stations, (slot or symbol muting can help)
  • Embodiments relate to a frame length to be extended to reduce lost overhead of the TDD frame switching (guard period) per frame - this may benefit from more ABS to reduce intercell interference (frame length should be aligned with overall RTT due to orbital delay (e.g. 10ms, 20ms or larger)
  • NTN non-terrestrial networks
  • GEO geostationary orbit
  • LEO low earth orbit
  • the path length of signals origination may vary considerably.
  • Embodiments further address challenges related to:
  • Embodiments are related, amongst others, to a Core problem for TDD:
  • an effective TA as known from the art maybe outdated for particular or many UEs.
  • Embodiments have also recognized that this is, at least in part, possibly but not necessarily an issue in FDD.
  • Embodiments further address the following problem: an accurate knowledge about which slots are available entirely or in part (e.g., which symbols) for individual UEs which may cause waste of resources or UL collisions.
  • the embodiments may provide for one or more of the following: a feedlink delay is provided by gNB/satellite via SIB19 a UE can calculate a service link distance and delay based on ephemeris data - but this absolute delay is possibly not known to gNB for a random access procedure, RACH, the UE is estimating the correct TA to compensate all delays (e.g., time of flight, ToF).
  • the gNB may detect residual deviation and provide a TA compensation signal/command to compensate for the deviation, e.g., by providing information indicating the deviation to the UE to determine a compensation by the UE, implicit instruction, and/or by directly or explicitly instructing the UE with a parameter.
  • the TA command corresponding to the RACH message may be outdated, when arriving at the UE due to movement of the satellite (e.g., a movement of UE even at 1.000 km/h is equivalent to 40 m and therefore negligible in terms of TA deviation).
  • a satellite movement may contribute to a drift of the absolute TA compensated by the UE; an additional insight relates to one or more of: o in TDD the NTN may be configured with flexible slots (S) to compensate for the maximum differential delay of a given NTN cell (e.g., based on a user distribution) o if these radio resources are not used, this may cause inefficient resource utilization and large or varying response delays.
  • S flexible slots
  • Fig. 3 shows a schematic diagram of UEs 312i, 312 2 , 312 3 , e.g., UEs in accordance with the UEs described in Fig. 1 , being located within an area 332, e.g., a coverage of satellite Si, e.g., carrying a gNB.
  • a common delay, CD is present that may be determined based on the speed of light, c, and the distance d1.
  • Additional distances d2 and d3, starting from d1 towards UE 312 2 , 312 3 respectively lead to additional, UE-specific delays, from which d2 may be the maximum, by way of example.
  • a differential delay, DD, of UE 312 3 may be determined based on d3/c.
  • the differential delay, DD, of UE 312i being located at d1 may be considered as being 0.
  • Timing Advance reporting procedure is used in a non-terrestrial network or an air-to- ground network to provide the gNB with an estimate of the UE's Timing Advance value (i.e., a Threshold Timing Advance, 7TA, as defined in the UE's TA formula, see TS 38.211 clause 4.3.1).
  • a Threshold Timing Advance 7TA
  • RRC controls Timing Advance reporting by configuring the following parameters: -offsetThresholdTA o example: Between 1 ms and 16 ms: every drift of e.g. 1 ms the UE is configured to send a report, the report may contain an absolute value, trend, etc. o some of the drift could be compensated by the UE, but when certain slot or symbol boundaries cannot be pre-compensated by the UE, this has to be reported in advance considering scheduling delay, RTT etc. o drift may be calculated/estimated from the expected or predicted trajectory of the basestation with or without the consideration of ephemeris data. embodiments of the present invention relate to
  • Timing Advance Report may be triggered if any of the following events occur: o upon an indication from upper layers to trigger a Timing Advance report; o upon configuration of offsetThresholdTA by upper layers, if the UE has not previously reported Timing Advance value to current Serving Cell; o if the variation between the current estimate of the Timing Advance value and the last reported Timing Advance value is equal to or larger than offsetThresholdTA, if configured.
  • SotA a UE only reports, in case of a mismatch
  • the MAC entity shall operate according to embodiments and recognitions described herein
  • Fig. 4a shows a schematic block diagram of a part of a known NTN 400 that may be modified by implementing the embodiments described herein.
  • a satellite such as satellite Si may travel on a satellite orbit 402, e.g., flying at a height 404, e.g., 800 kilometres above ground surface 406 of earth 408.
  • Satellite Si may maintain a connection to a first UE 312i, UE A, and to a second UE 312 2 , UE B, being spaced by a distance 414, e.g., 500 kilometres. Due to those large distances, a path length L A of a path 4161 may be considerably longer when compared to a length LB of a path 4162 to UE 312 2 .
  • Fig. 4b there is shown a schematic representation of wireless communication network 400 that has changed its relative positions between satellite Si of a time instance ti shown in Fig. 4a to a different relative position in time instance t 2 leading to a change of path lengths between the respective UEs and the satellite and, thereby, to a considerable change in the relative timing.
  • embodiments provide for an efficient communication under the consideration of the fast relative movement between a satellite or other types of non-terrestrial nodes, possibly but not necessarily comprising a base station, and a terrestrial node such as a UE. Besides the fast change of the distances, the large variations of distances between same UEs such as UE 312i and 312 2 of network 400 may lead to room for improvement at least partially used by embodiments described herein.
  • embodiments in accordance with the present invention disclosed herein proposes to use solutions described herein. In subsections embodiments further to present the proposed technical solutions in the form of embodiments.
  • Embodiments are described in connection with satellites carrying or comprising a base station. However, embodiments are not limited to a use of satellites but may also be applied to any scenario in which there are significant differences in the distances of the communication links.
  • satellite platforms including all LEO, MEO and GEO orbits
  • airborne platforms including both manned and unmanned vehicles, drones and/or balloons are part of the invention as well as base stations on the ground.
  • embodiments described herein relate to a gNB being part of a satellite, embodiments are not limited hereto.
  • Other types of non-terrestrial devices such as high altitude platforms, balloons, or the like may be used.
  • terrestrial base stations and/or terrestrial networks may benefit from the disclosure provided herein although not suffering from that large delays as well as compared to NTN-configurations.
  • Embodiments of the present invention relate to implement a structure of an effective frame structure that is capable of compensating for large variations of a distance between two nodes and an associated large variation of round-trip-times, times-of-flight of signals and the like.
  • a frame structure such as a TDD frame may be implemented as a varying effective frame structure that may be same but also different for different terminals, e.g., UEs, operating in a cell of a wireless communication network.
  • Such an effective frame structure may consider that a UE may adjust the timing advance, TA, depending on its distance from the satellite (round-trip-time, RTT) so that it arrives at the satellite in line with a possibly fixed frame structure.
  • a UE possibly refrains from using certain DL slots or symbols and/or UL slots or symbols or uses them only partially, i.e., performing a non-use of at least a part of at least one slot. This may be based on or dependent from a currently relevant round trip time (RTT) of the terminal. For example, such behaviour may be controlled or triggered by scheduling.
  • RTT round-trip-time
  • a halfduplex UE can either receive or transmit at an instance of time, so it is preferred that scheduled DL and UL slots do not overlap in the UE's time base. If this is the case, a UE according to an embodiment may either skip or ignore the DL reception or the UL transmission, e.g., based on an own decision, e.g., a current data traffic, priority levels or the like and/or based on a preconfigured or configured decision.
  • the UE may be adapted to implement the non- use of the resources, e.g., slot or parts thereof for the effective frame structure to avoid the use of scheduled resources DL and UL which have a temporal overlap in the effective frame structure, i.e., to resolve the conflict caused by the overlap.
  • the resources e.g., slot or parts thereof for the effective frame structure to avoid the use of scheduled resources DL and UL which have a temporal overlap in the effective frame structure, i.e., to resolve the conflict caused by the overlap.
  • a basestation e.g., located at satellite Si
  • a temporal overlap and, thus a conflict, at the UE may arise between DL slots and UL slots within a same frame, e.g., as a switching from DL to UL has to be performed resulting in a time for the UL where still DL is scheduled.
  • the varying effective frame structure may consider or be correlated with a variation of the timing advance caused by changes of the distance between two nodes exchanging signals.
  • Such variation may be based on, e.g., an orbit of a satellite or other reasons and may be optionally be influenced by further parameters such as an effective field of view through which the satellite may travel, the effective field of view forming boundaries between minimum and maximum distances between a user terminal and the satellite such that a variation in the effective field of view may also cause a change in the effective frame structure variation.
  • both UE 312i and 312 2 may benefit from a possibly undisturbed LOS therefore being possibly served by satellite Si.for a large amount of a path along the orbit 402 therefore experiencing possibly a significant variation of lengths L A and/or L B .
  • an effective field of view of a UE towards the sky may be limited, therefore only providing a LOS to satellite Si in a narrow range, and thus, the variation of the distance to the satellite may also be limited.
  • the device may select one of the overlapping resources, e.g., DL resources or UL resources from the overlapping resources and use them whilst non-using the others.
  • the overlapping resources may be part of a same frame or of different frames.
  • the overlap is not necessarily an explicit overlap of the resources in the time-frequency grid but may, as an alternative or in addition, relate to a conflict occurring by operating on the resources, e.g., signal processing switching between DL and UL and the like, which is to be considered at a device operating in half-duplex.
  • Devices with partial or full duplex capability may be configured for simultaneous reception and transmission wherein the non-use of particular DL or UL resources may depend on or be based on the frequency allocation pattern.
  • Such a non-use or a decision about the non-use, optionally including the decision for a use, may be fed back by the UE, i.e. , the UE may be adapted for providing a feedback indicating whether the device has performed resolving of a conflict caused by overlapping resources and/or which resolving, e.g., whether DL, S and/or UL slots or parts thereof where unused and/or which of them and/or that it used some or all of the scheduled resourced.
  • effectively usable parts of the frame structure may differ between two UEs, e.g., due to scheduling.
  • a UE may operate on an effective frame structure, slot structure or symbol structure that may change dynamically or may be specific to the UE due to channel parameters (e.g. UE-satellite distance, RTT, window of coverage opportunity, etc.).
  • the effective frame structure, slot structure and/or symbol structure can be identical, similar or individual and would therefore be different from other UEs.
  • a first embodiment relates to a user equipment, UE, comprising a wireless interface for receiving wireless signals and for transmitting wireless signals; wherein the UE is configured for operating in a cell of a wireless communication network according to a time division duplex, TDD, scheme that comprises a plurality of TDD frames, each TDD frame comprising a plurality of slots arranged according to a frame structure, the plurality of slots comprising a first number of downlink, DL, slots, a second number of uplink, UL, slots and a third number of special, S, slots e.g., arranged between the first number of UL slots and the second number of UL slots; wherein the UE is configured for operating with a varying effective frame structure within the TDD scheme to compensate for varying distances between the UE and a base station operating the cell.
  • TDD time division duplex
  • the UE is adapted to operate with a dynamically varying effective frame structure based on a dynamically varying distance.
  • the UE is adapted to operate with the varying effective frame structure as varying based on a channel parameter such as a round-trip-time, RTT or a window of coverage opportunity for the UE.
  • a channel parameter such as a round-trip-time, RTT or a window of coverage opportunity for the UE.
  • the effective frame structure is UE specific.
  • the base station operating the cell is a non-terrestrial base station.
  • the UE is configured for a non-use of at least a part of at least one of the S-slots of the plurality of slots of the TDD frame.
  • the UE is adapted to implement the non-use for the effective frame structure to avoid a temporal overlap of a slot scheduled for DL, e.g., a slot of the first number of slots or a slot of the third number of slots, and associated with a first frame, and a slot scheduled for UL, e.g., a slot of the second number of slots or a slot of the third number of slots, and associated with the first or a second frame.
  • a slot scheduled for DL e.g., a slot of the first number of slots or a slot of the third number of slots
  • a slot scheduled for UL e.g., a slot of the second number of slots or a slot of the third number of slots
  • the UE is adapted to skip or ignore one of a) at least a part of a first slot scheduled for DL and associated with a first frame and b) at least a part of a second slot scheduled for UL and associated with the first frame or a second frame in case of a temporal overlap between the first slot and the second slot; or vice versa.
  • the device is adapted for providing a feedback indicating whether the device has performed resolving of a conflict caused by overlapping resources and/or which resolving
  • the varying effective frame structure relates to a variation in at least one of a frame structure, a slot structure within the frame and/or a symbol structure within the frame.
  • the UE is configured for, e.g., directly after initial access or a different time and once or multiple time, e.g., periodically, signalling slots or symbols unusable for UL and/or DL, e.g., unusable due to a timing advance, TA, drift, for DL or UL explicitly or implicitly by e.g. indicating an absolute round trip time, a drift, a first drift derivative or a second derivative etc.
  • the effective frame structure is based on a scheduled frame structure from which at least one slot of the third number of slots that is scheduled for uplink or downlink remains unused by the UE.
  • the UE is configured for predicting and reporting a drift affecting the UE
  • the UE is configured for monitoring additional DL slots or symbols and/or for preparing a transmission in additional UL slots or symbols according to an allocation of special, S slots provided by the base station.
  • the UE is adapted to align to a first frame structure or TDD scheme implemented by the base station as a first base station and to align to a second frame structure or TDD scheme implemented by a second base station for preparing a handover from the first base station to the second base station.
  • the UE is configured for aligning the second frame structure or TDD scheme based on at least one of:
  • the UE is configured for aligning to the first or second frame structure or TDD scheme based on at least one message received in a connected mode and/or in an idle mode of the UE.
  • the UE is configured for temporally aligning the TDD frame with the base station for reception within the frame.
  • the UE is configured for temporally aligning the TDD frame with the base station for a transmission of the UE within the frame.
  • the UE is configured for using the S-slots of the plurality of slots of the TDD frame for an UL transmission or a DL communication based on a distance of the UE from the base station.
  • the UE is configured to evaluate a signal received and containing an allocation of the S-slots according to a group identifier indicated in the signal and to determine, based on the group identifier, whether the UE is a part of the indicated group and to implement the allocation when being a member of the group.
  • a sequence of S-slot usage of the third number of S-slots in the TDD frame for DL or UL is predetermined and/or specific per flight path, wherein the UE determines the S- slot usage from a signalling of the base station or from information indicating the flight path.
  • the UE when referring back to the twenty-fourth embodiment, is configured for providing a measurement report to indicate, to the base station, a location of the UE with regard to the flight path.
  • the UE is adapted to report a periodicity of timing advance and/or a granularity of reporting with an interval of at least or at most 1 ms.
  • a twenty-seventh embodiment relates to a base station comprising a wireless interface for receiving wireless signals and for transmitting wireless signals; wherein the base station is configured for operating a cell of a wireless communication network according to a time division duplex, TDD, scheme that comprises a plurality of TDD frames, each TDD frame comprising a plurality of slots arranged according to a frame structure, the plurality of slots comprising a first number of downlink, DL, slots, a second number of uplink, UL, slots and a third number of special, S, slots e.g., arranged between the first number of UL slots and the second number of DL slots; wherein the base station is configured for allocating to different terminals in the cell and within the TDD scheme a varying effective frame structure, e.g., a different number or position of the DL or UL slots in the frame structure and/or a different symbol configuration of at least one S slot, e.g., an OFDM symbol configuration and/or a different length of at least one
  • the different effective frame structures within the TDD scheme relate to at least one of a number of S slots between a last downlink slot and a first uplink slot, a number of S slots within the TDD frame, a position of the UL slots within the TDD frame and a symbol configuration within at least one S slot being scheduled differently to different terminals or used differently by different terminals.
  • the symbol configuration relates to at least one of a location of symbols in a time frequency grid, a number of symbols in the slot and a use of the symbol as uplink symbol, downlink symbol or guard symbol.
  • the base station is configured for allocating at least one of the S slots for a different use for different terminals within the cell.
  • the base station is at least a part of a flying device such as a satellite, a drone or a balloon.
  • the base station is configured for selecting a frame structure of the TDD scheme, e.g., from a plurality of different frame structures or different TDD schemes, based on an altitude, e.g., of an orbit or flight path, of the flying device.
  • the base station is configured for grouping terminals in the cell and for groupwise allocating the at least one of the S slots differently for different groups of terminals.
  • the base station is configured for selecting the frame structure or TDD scheme from a plurality of frame structures or TDD schemes, the frame structures or different TDD schemes differing in at least one of a time duration of one, more or all slots of the TDD frame, a number of slots of the frame, a number of UL slots in the frame, a number of DL slots in the frame and a number of S slots in the frame.
  • the base station is configured for selecting the frame structure or TDD scheme based on the position/location of a UE or a group of UEs and the location of the gNB, e.g., along a flight path of a flying device comprising the base station while providing coverage /service to the cell.
  • the S slots are arranged between the DL slots and the UL slots; wherein the base station is configured for allocating the S slots for DL or UL operation for the different terminals.
  • the S slots are arranged between the DL slots and the UL slots; wherein the base station is configured for allocating, to one or more terminals with a larger distance from the base station a larger number of S slots to compensate a larger TA requirement for UL transmissions.
  • the base station is adapted to increase a frame length for the terminals with the larger distance, e.g., increasing the first number of DL slots and/or the second number of UL slots.
  • the base station is adapted to increase the frame length for all terminals in the cell based or in accordance with a largest round trip time or largest distance of a terminal in the cell served by the base station
  • the base station is configured for allocating remaining S slots for additional DL traffic and/or additional UL traffic.
  • the base station is configured for allocating the remaining S slots differently for different terminals.
  • the base station is adapted for operating the cell with a frame duration of at least 15 ms.
  • the base station is configured for a synchronized arrival of signals received from the different terminals, e.g., by use of a timing advance, TA.
  • TA timing advance
  • the base station is configured for allocating the slots according to a configuration according to which, at the base station and/or the terminal, within a single frame only one transition between DL and UL is implemented.
  • the base station is configured for allocating the slots according to a configuration according to which, at the base station and/or the terminal within a single frame more than one transition between DL and UL is implemented.
  • the base station is configured for mapping resources of a wireless communication along at least two adjacent slots.
  • the base station is configured for mapping resources of a wireless communication along at least two adjacent slots, wherein the resources of a first slot are used partially at an end of the first slot and are continued with resources at the consecutive second slot wherein at least the beginning of the at least second slot is used.
  • the base station is configured for allocating additional flexible slots and/or symbols for at least one of DL, UL and a guard period and to signal such allocation, the allocation being valid for individual terminals or terminal groups.
  • the base station is configured for allocating only S slots for additional DL transmissions that are received partially or entirely by the targeted terminal based on a round-trip time, RTT, associated with the terminal.
  • the base station is configured for receiving information about an absolute and/or relative slot and/or symbol level shift of the terminals and for allocating the at least one S slot to compensate for differences in the shifts.
  • the base station is configured for allocating, to at least one terminal at least one of a DL slots and UL slots prior to or after regular UL slots according to the frame structure or TDD scheme.
  • the base station is configured for predicting a drift affecting the UE
  • the base station is configured for coordinating the frame structure or the TDD scheme with another base station, e.g., a base station subsequently serving the cell or the terminal.
  • the base station is configured for receiving, from at least one terminal assistance information and to allocate the slots based on the assistance information indicating at least one of: o a global navigation satellite system, GNSS, and o a timing advance, TA, used by the terminal, e.g., between last DL symbol or slot received and the first UL symbol or UL slot to be sent or a derivate of the TA.
  • assistance information indicating at least one of: o a global navigation satellite system, GNSS, and o a timing advance, TA, used by the terminal, e.g., between last DL symbol or slot received and the first UL symbol or UL slot to be sent or a derivate of the TA.
  • the base station is configured for allocating the slots based on a concatenation of at least two different frame structures.
  • the concatenation of at least two different frame structures forms a frame set, the frame set being one of a plurality of different frame sets being formed by different concatenations of frame structures; wherein each frame set is associated with a frame set identifier, wherein the base station is configured for indicating a selected frame set form the plurality use of a specific frame set by signalling the associated frame set identifier.
  • the base station is configured for operating the cell in FR1 , FR2 and/or FR3
  • the base station is configured for selecting the frame structure for the TDD scheme to support time delays caused by distances between the terminal and the base station being exemplarily at least 600 km and/or at most 2,000 km or a different flight height or orbit.
  • the base station is adapted for allocating a use of the S-slots of the plurality of slots of the TDD frame for an UL transmission or a DL communication individually for different terminals or groups of terminals according to a distance of the terminal from the base station, e.g., based on a terminal-by-terminal; or group-by-group-basis.
  • the base station is configured for allocating at least one of the S-slots of the plurality of slots of the TDD frame as being unused for uplink and unused for downlink at the terminal for at least one terminal.
  • the base station is configured for adapting the number of the third number of S-slots over time based on a changed elevation angle with regard to the base station experienced by the terminals served by the base station.
  • the base station is configured for adapting the scheduling along a flight path of the flying device with respect to the terminal.
  • the base station is configured to schedule the S-slots for the terminal as a member of a group of terminals and commonly for the group of terminals, e.g., formed based on a proximity or distance between the terminals; wherein the base station is configured for signalling the allocation to the group of terminals, e.g., using a group identifier; or for signalling the allocation individually to the terminal.
  • a sequence of an S-slots usage for DL or UL is predetermined and/or is specific per flight path, the base station being a part of a flying device.
  • the base station is configured for selecting the frame structure for the TDD scheme to support a worst-case time delay associated with a longest distance between any of the terminals in the cell and the base station.
  • the base station is configured for simultaneous transmission and reception and for allocating a same S-slot or at least one symbol for an UL transmission of a first terminal or a first group of terminals in the cell and for a DL reception of a second terminal or a second group of terminals in the cell.
  • the base station is configured for configuring S-slots or symbols used for simultaneous reception and transmission at the base station to be operated in a Sub Band Full Duplex, SBFD, mode.
  • the base station is configured for implementing a partitioning of S-slots for simultaneous UL usage and DL usage within one S-slot according to an overlap or not-overlap fashion over a frequency domain, e.g., with respect to sub-bands, with respect to the time domain, e.g., using OFDM symbols, or a combination thereof.
  • the base station is configured for selecting at least one resource block of an S-slot for mapping user plane data for a terminal served by the base station based on information indicating that the selected resource block is accessible for the terminal, e.g., based on the base station being at least a part of a flying device.
  • the base station is configured for mapping a code word or user data to be transmitted onto a subset of OFDM symbols of one S slot, the subset selected based on information that the selected subset is accessible for the terminal, e.g., based on the base station being at least a part of a flying device.
  • the base station is configured for mapping a code word or user data to be transmitted onto a combination of a first subset of OFDM symbols of a first S slot and a second subset of OFDM symbols of a second, possibly consecutive, second S slot based on information that the selected subset is accessible for the terminal, e.g., based on the base station being at least a part of a flying device.
  • the base station is configured for adapting a coding level to encode a code word or user data to be transmitted according to a number of usable OFDM symbols within a slot such as an S slot to use usable OFDM symbols within the slot, e.g., based on the base station being at least a part of a flying device.
  • the base station is configured for signalling a list of frame structure configurations, e.g., as a dedicated signal or a broadcast signal to one or more terminals during a configuration phase and for instructing at least one terminal within at least one of a cell a beam provided by the base station or a group to activate a certain frame structure based on the distance of the at least one terminal from the base station, e.g., implicitly or explicitly.
  • a list of frame structure configurations e.g., as a dedicated signal or a broadcast signal to one or more terminals during a configuration phase and for instructing at least one terminal within at least one of a cell a beam provided by the base station or a group to activate a certain frame structure based on the distance of the at least one terminal from the base station, e.g., implicitly or explicitly.
  • the base station is configured for managing the frame structure based on a topology of the network, e.g., based on a NR cell or flying device beam size, a mapping between the NR cell, NR beam (SSB), and the flying device beam.
  • a topology of the network e.g., based on a NR cell or flying device beam size, a mapping between the NR cell, NR beam (SSB), and the flying device beam.
  • the base station is a part of a flying device and configured for allocating a same TDD frame structure for all terminal within the cell based on a scenario where a small or a large NR cell is provided by the base station and a one-to-one mapping between the NR cell, a flying device beam, and a NR beam, e.g., SSB is operated by the base station; wherein the base station is configured to broadcast a list of frame structure configurations using system information messages such as SIB1 , SIB19 for NR-NTN, and SIB31 , e.g., for loT-NTN, e.g., of terminals being in an idle mode, RRCJDLE.
  • SIB1 , SIB19 for NR-NTN, and SIB31 e.g., for loT-NTN, e.g., of terminals being in an idle mode, RRCJDLE.
  • the base station is configured for updating the list of frame structure using the periodic signalling, e.g., SIB1 , SIB19, or SIB31.
  • the periodic signalling e.g., SIB1 , SIB19, or SIB31.
  • the base station is configured for updating the list of frame structure and to indicate the terminals explicitly and/or implicitly to update their frame structure within the cell, e.g., using either DCI in the PDCCH or MAC-CE in the PDSCH, e.g., based on a changed distance between the terminal and the base station.
  • an explicit indication relates to an explicit indication by the base station to which frame structure the terminal may use; and/or wherein an implicit indication relates to an implicit indication of which frame structure the terminals may use by instructing the terminals within a certain time/location/group to change their frame structure after a certain time, e.g., due to a mobility of the base station.
  • the implicit indication comprises a time-based trigger or a location-based trigger.
  • the base station is a part of a flying device and configured, in a scenario where a large NR cell, with one-to-one mapping between the NR cell and the flying device beam and multiple NR beams, e.g., SSBs, within the NR cell, for grouping group terminals in the cell based on their serving NR beam, SSB within the flying device beam/NR cell.
  • a large NR cell with one-to-one mapping between the NR cell and the flying device beam and multiple NR beams, e.g., SSBs, within the NR cell, for grouping group terminals in the cell based on their serving NR beam, SSB within the flying device beam/NR cell.
  • the base station is configured for broadcasting a list of frame structures using system information messages for all terminals in RRCJDLE and RRC_ACTIVE on a satellite-beam basis; and/or to use periodic transmission of SIB messages to periodically update the list of frame structures; and/or to update the list using RRC_messages in a dedicated manner for terminals in RRC_ACTIVE.
  • the base station is adapted for a relaying of signals via an inter satellite link, ISL, wherein the base station is configured for updating the frame structure based on an ISL changeover between a serving satellite and at least one relaying satellite based on a triggered change in distances of the terminals back to the base station.
  • ISL inter satellite link
  • the base station is configured for grouping the terminals in the cells based on a serving NR beam, e.g., SSB or serving satellite beam; and/or to allocate all terminals served by the same NR beam or satellite beam with a same frame structure.
  • a serving NR beam e.g., SSB or serving satellite beam
  • the base station is a part of a flying device and configured, in a scenario where a large NR cell is operated by the base station the base station is configured for using information related to a timing advance reported by the terminals to estimate a distance of the terminals and/or a round trip time, RTT, from the base station to classify the terminals into contours or groups based on their distances.
  • the base station is configured for informing a different base station about the allocated TDD structure or frame structure, e.g., using an ISL/Xn interface, an NG for NR-NTN/X2, and S1 for loT-NTN; and/or to receive such information from a base station operating the cell prior to the base station and to operate accordingly.
  • the base station is configured for flexibly allocating OFDM symbols within at least one S slots for DL, UL or guard symbol.
  • a hundredth embodiment relates to a method for operating a UE, the method comprising operating the UE in a cell of a wireless communication network according to a time division duplex, TDD, scheme that comprises a plurality of TDD frames, each TDD frame comprising a plurality of slots arranged according to a frame structure, the plurality of slots comprising a first number of downlink, DL, slots, a second number of uplink, UL, slots and a third number of special, S, slots e.g., arranged between the first number of UL slots and the second number of UL slots; operating the UE with a varying effective frame structure within the TDD scheme to compensate for varying distances between the UE and a base station operating the cell.
  • TDD time division duplex
  • a hundred-first embodiment relates to a method for operating a base station, the method comprising: operating a cell of a wireless communication network according to a time division duplex, TDD, scheme that comprises a plurality of TDD frames, each TDD frame comprising a plurality of slots arranged according to a frame structure, the plurality of slots comprising a first number of downlink, DL, slots, a second number of uplink, UL, slots and a third number of special, S, slots e.g., arranged between the first number of UL slots and the second number of DL slots; allocating to different terminals in the cell and within the TDD scheme a varying effective frame structure, e.g., a different number or position of the DL or UL slots in the frame structure and/or a different symbol configuration of at least one S slot, e.g., an OFDM symbol configuration and/or a different length of at least one slot in the time domain, to compensate for different distances between the different terminals and the base station.
  • a hundred-second embodiment relates to a computer readable digital storage medium having stored thereon a computer program having a program code for performing, when running on a computer, a method according to the hundredth or hundred-first embodiment.
  • Embodiments of the present invention are related to and based on a recognition that a measurement configuration for UEs may be updated, e.g., automatically, regularly, or based on an event, to avoid that UE measures when already sending uplink, UL, transmissions.
  • one or more nodes of the wireless communication network may evaluate or check how often a measurement report or a specific task, e.g., channel state information, CSI, channel quality indicator, CQI, precoding matrix indicator, PMI, or others has to be sent.
  • embodiments relate to a user grouping and/or pairing, e.g., implemented as an algorithm. For example, if many users are clustered in one end of the cell with a specific delay and other users are not active, then the statistical user group being gain might be lower, but in case of a few users, more resources are available per users in return.
  • At least some of the embodiments described herein are based on the assumption to use a fixed guard period in a frame structure in connection with a use of fixed DL/UL patterns with flexible slots or flexible symbols, S.
  • Fig. 5 shows a schematic block diagram for illustrating an aspect of the present invention according to which a basestation, e.g., located at satellite Si, comprising a wireless interface for receiving wireless signals and for transmitting wireless signals is configured for operating a cell of a wireless communication network according to a TDD scheme that comprises a plurality of TDD frames such as a frame 502.
  • a basestation e.g., located at satellite Si
  • a wireless interface for receiving wireless signals and for transmitting wireless signals
  • a cell of a wireless communication network according to a TDD scheme that comprises a plurality of TDD frames such as a frame 502.
  • Fig. 5 is based on Fig. 3 whilst only making reference to UE1 and UE3 of Fig. 3, UE3 being now named UE2.
  • Each TDD frame 502 may comprise a plurality of slots 504i to 504 n that are arranged according to a frame structure.
  • the plurality of slots comprises a first number of downlink, DL, slots e.g., slots 504i to 504 a , a second number of uplink, UL, slots, e.g., slots 504d to 504 n and a third number of special, S, slots, e.g., 504b to 504 c .
  • the special slots 504b to 504 c may be arranged between the UL slots and the DL slots.
  • a set 506 of preferably continuously arranged S slots may provide for a guard period with a duration that is preferably larger than two times the NDD plus two times the common delay, CD with regard to the regular pattern duration, RPD, of pattern 502.
  • the common delay CD 512 may but is not required to be longer in time when compared to the regular pattern duration RPD 514.
  • Maximum differential delay, MDD, 516 may be comparatively small when compared to common delay, CD, 512 but may still add for a considerable amount of time delay.
  • Fig. 5 shows a UE dependent/distance dependent effective TDD slot configuration according to an embodiment that may be applied.
  • This may include uplink, UL, to be transmitted earlier, e.g., for UEs far away, or later, e.g., for UEs closer to the satellite.
  • the remaining S-slots may be used for DL transmission, which again have to scheduled according to the distance of the UEs. However, those slots may remain usable whilst not being necessarily limited to a guard period.
  • a position and/or an amount of S-slots may be allocated differently to UE1 and UE2. For example, between UL-slots and DL-slots, a low amount of S-slots is allocated to UE1 being closer to the satellite when compared to UE2 to which a larger amount of S-slots is allocated, compare S-slots 506bi used for UE1 being lower when compared to a number of S-slots 506b2 used for UE2, e.g., based on the delay, the RTT and/or the distance.
  • a higher of number of S-slots may be allocated between DL-slots and UL-slots for UE1, see S-slots 506ai, when compared to UE2 which may have lower or even no S-slots therebetween.
  • usable slots may be different for different UEs at a given point in time, that is a different effective frame structure may be operated for different UEs at that given point in time.
  • a timing advance, TA, of UE1 may correspond to two times the CD
  • UE2 may operate according to a TA that is two times the CD and two times the MDD.
  • Embodiments of the present invention may use one or more of the following implementations. That is, items of a proposed solution that are described in the following may be implemented commonly, individually or group-wise.
  • flexible slots can be used for additional UL or DL traffic. This may be scheduled to specific users or groups thereof which are able to continue DL reception or UL transmission in these slots. In connection with this, it may be of advantage to extend DL reception into S- slots or to have S-slots prior to DL slots to allow an early start of the downlink. Similarly, S- slots preceding UL slots may allow for an early start of UL and S-slots following UL slots may allow for extending the uplink.
  • embodiments relate to providing the base station, gNB, e.g., informed by a UE message or by the network, about an absolute and/or relative shift, e.g., on a slot level or a symbol level, to accommodate for the right slot or symbol selection in the S- slots.
  • a device such as a UE may signal those slots or symbols, e.g., explicitly and/or implicitly, by e.g., a drift, drift derivate or second derivate or the like. That is, the UE may explicitly and/or implicitly inform the network, e.g., the base station, about slots and/or symbols subject to a TA drift.
  • the DL slots and/or UL slots located earlier and/or later compared to the regular UL slots and/or DL slots.
  • additional UL slots or DL slots can be earlier than the regular UL slots and the additional DL slots can be later than the regular UL slots.
  • the drift of the UL specific usable additional slots or symbols may be predicted by the UL and/or gNB and the result of such calculation may be used.
  • various methods of signalling, prediction or the like may be used.
  • a trade-off may be done between a more precise calculation of a drift, e.g., using more computational resources and/or time and/or to save time whilst allowing to have some sort of impreciseness.
  • embodiments consider the FTD TA reporting to be adapted for requirements in TDD. This may allow that the reporting is more frequent than defined in the current specification such as TS 38.321 section 5.4.8, timing advance report for FDD.
  • the UE when considering seamless handover, HO, from satellite 1 to satellite 2, e.g., in a case where satellite 1 moves out of sight of the UE and satellite 2 takes over, the UE is, according to embodiments, aligned to the effective DL and/or UL slots of both satellites, satellite 1 and satellite 2.
  • SIB 19 or enhancements or serving gNB may provide synchronization of sets, SYZ offsets, and/or information indicating an initial slot structure of the new gNB for a faster synchronization and initial access.
  • different gNBs may be received by the UEs with time shift depending on the position of the satellites and the positions of the UEs.
  • embodiments may provide for an advantageous modification to enable an efficient use of resources within an NTN network.
  • Embodiments are based on a consideration of different beam diameter configurations, which may be 50 km or larger.
  • the coverage cells may result in larger maximum differential delay and therefore may benefit from a longer frame structure.
  • a larger footprint on the ground may be obtained when compared to constellations having a higher number of satellites.
  • Embodiments relate to calculating a maximum differential delay, MDD, and propose a frame structure design consisting of K DL slots + IS-slots + mUL-slots.
  • a frame length in NTN may, but is not required to be fixed.
  • any number of S-slots may be introduced to provide for usable resources.
  • 11 satellites that provide, e.g., 48 spot beams in one orbital plane, e.g., 66 in total, may lead to each beam being about 600 km in diameter providing for a total footprint her satellite of approximately 4700 km. This may result in comparatively broad beams.
  • An example slot structure used by Iridium is 90ms of a TDD frame that is divided into 20 ms DL, 4 x 8.2 ms uplink and 4x DL slots with several variable guard times.
  • Embodiments allow for a combination of MDD and sub-carrier spacing SCS. That is, a frame length may require more S-slots than another frame with a smaller SCS.
  • Embodiments propose to fix a frame structure under consideration of RTT and MDD.
  • the use of the S-slots may be dynamic, depending on RTT between the UE and the satellite. For example, embodiments propose to increase a frame structure for a large RTT, e.g., 40 ms frame length and 20 ms of S-slots. Such implementation may be executed by the base station, signalled to the UE and/or may be based on a feedback received from the UEs.
  • the base station can schedule an additional DL and/or UL opportunities for individual UEs or UE-groups.
  • Possible solutions may be assistance information from the UE.
  • a global navigation satellite system. GSS, report may be provided, e.g., from the UE to the satellite.
  • a GNSS-less report may be transmitted, e.g., the UE may report a TA used between the last DL slot received and the first UL symbol to be sent. This may be implemented under the consideration to avoid an outdating of TA while the satellite is moving, e.g., by predicting the value for the future.
  • the UE may provide future TA evolution e.g., as a first and/or derivate, by signalling which may allow to have a UE specific equivalent of signalling from gNB in SIB19.
  • a frame structure as proposed according to embodiments allows to be well suited for a long RTT.
  • the frame structure may comprise one or more of the following: for example, a concatenation of multiple frame structures that may be same or different when compared to each other may be used.
  • two different frame structures are combined in a combined frame structure to overcome deficiencies of known systems that allow a concatenation of two same frames.
  • embodiments relate to cover all numerologies, e.g., between 15 kHz and 120 kHz.
  • embodiments may be implemented in FR1 , FR2 and/or FR3.
  • a TDD spectrum may be available for S2E and E2S, i.e. , satellite- to-earth and earth-to-satellite.
  • the frame length is designed to follow the longest path when flying over the ground. For example, when considering a 600 kilometre altitude, a distance between 600 and 2000 kilometres may apply and said distance may at least influence the frame length.
  • a long frame may comprise a structure according to which a first amount of downlink slots is followed by a second amount of special slots which is followed by a third amount of uplink slots as shown, for example, in Fig. 5.
  • the S-slots may be used to compensate for RTT and may be used for additional DL and/or UL for specific users.
  • a frame structure may be adapted to the orbit altitude. That is, for a different altitude, e.g., a higher altitude, a slot length and/or a number of slots of group downlink, special and/or uplink may be adapted.
  • a multi-orbit constellation may rely on different frequencies to be used to different orbits and/or satellite constellations.
  • embodiments provide for frames operated by the base station that have a length which corresponds to the largest delay in the cell. For example, referring to a 600 kilometre orbit, the RTT may be between 4ms and 30ms. According to such embodiments, the frame may have a sufficient length of S-slots covering 13ms. When applying, e.g., a 20ms total frame length, embodiments may use 30ms of those 20ms for S-slots, e.g., splitting the remaining 7ms into 5ms used for DL-slots and 2ms for UL-slots or differently.
  • the frame may comprise 5ms of DL-slots, 13ms of S-slots and 2ms of UL- slots.
  • a longer total frame length may reduce loss of efficiency due to number of S-slots but may increase latency when switching from UL to DL and vice versa.
  • a trade-off may be established, e.g., when operating a network for different purposes.
  • all S-slots which are not used by a particular UE to compensate for RTT can be used either for additional UL or DL traffic, wherein the group of S-slots may be use for one or both of UL and DL.
  • such an allocation may be scheduled by the gNB when signalled to the UE or group of UEs, e.g., using CORESETs.
  • the gNB may provide different frame structures depending on a contour of the cell, e.g., when determining RTT to have a first range, e.g., between 1 and 5 ms, a first configuration A may be used and when determining a different RTT, e.g., between 6 and 10 ms, a different configuration b may be used or realized.
  • the UE may know which configuration is valid at a certain time and/or at a certain location. This does not prevent a signalling to the UE, e.g., from the base station.
  • the contour may refer to a UEs experiencing the same or a similar RTT or a delay, time-of-flight of the signal between the UE and the gNB.
  • the TA and/or RTT may be concluded from GNSS and/or TA.
  • different slot structures may be valid for the same beams.
  • different slot structures may be used for different beams used by the base station.
  • different slot structures may be signalled in the same or different beams.
  • embodiments solve the issue of an inter-satellite frame structure coordination to avoid inter-frame interference during handover, HO, as described herein. This may be implemented, for example, by coordinating the frame structures between satellites, e.g., under consideration of a distance to the UEs.
  • a gNB may use knowledge about the RTT, e.g., down to a symbol level, to use only S-slots for DL transmission which can be received entirely by the targeted UE. This may benefit from a granularity being below OFDM symbol level. This may be done, e.g., as part of the TA adjustment procedure. An accuracy thereof is advantageously down to a cyclic prefix, CP, of an OFDM symbol. That is, the base station may evaluate whether an S-slot may completely be received by a targeted UE and may only such S-slots for DL that fit to this criterion.
  • a misalignment of directivity/tracking of an antenna may be a considerable or a dominant influence.
  • an antenna pattern in azimuth in FR1 may vary so that a full power could be a solution.
  • measurement reports for radio resource management e.g., a measurement configuration of the UE such as a DL measurement configuration may be used to improve communication.
  • the UE may be informed, explicitly and/or implicitly, to know if a particular S-slot is used for DL and/or UL.
  • the UE may predict the available or useful amount of resources for a period of time in the future and may report this to the base station.
  • a report may be configurable or predetermined, e.g., with regard to a varying granularity of the report, such as symbol-level, slot-level, or a set of slots.
  • the UE may report such resources at different granularity as capability reporting. For example, when the reporting is provided on an OFDM symbol level, the slot mapping and the modulation coding scheme, MCS, may be adapted with a same granularity and are preferably adapted accordingly.
  • Embodiments further provide, as an alternative in addition, to a change of an effective TTD frame configuration or a change of a frame configuration e.g., so that S-slots are used differently for different UEs or different groups of UEs.
  • embodiments may relate to the aspect of being in idle mode to define at which point the UE receives the configuration. This may mean that the UE may synchronize to the SSB and may receive information such as SI B 1 , but does not perform the RACH procedure. This may be signalled in SI B 1 or SI B 19/31 or in a different SIB.
  • a measurement configuration e.g., according to a minimization of drive test, MDT
  • gNB e.g., to the UE based on a consideration of updated TTD frame configuration, e.g., to avoid CLI which may be caused in case where some UEs transmits, some UEs receive in proximity.
  • a CLI for S- slots received by some UEs in DL while other UEs have to send UL signals to compensate for the TA may cause such a CLI. If such true UEs are well-separated, then the CLI may be nonharmful to the receiving UE.
  • Embodiments therefore provide to configure specific measurements to enable detection of CLI and provide CLI reports to the gNB as scheduling input. That is, the UE may be configured for providing CLI measurement reports.
  • the base station may be configured for establishing the frame structure based on CLI information related to CLI received by one or more UEs in order to mitigate or reduce the CLI.
  • different granularity of measurement configurations e.g., regarding slots, symbols, or the like and/or a periodicity or the like may be used. That is, different UEs may report, e.g., based on a local decision and/or based on configuration or instructions perform measurements on same or different granularities.
  • the UE may report a location of the UE.
  • the UE may report a potential drift, however, a variation of the UE may be small when compared to satellite movement.
  • the UE may report the timing advance, TAR, from the UE to the network as described above. This may benefit from a higher periodicity than every 1 ms. That is, according to embodiments, the UE may report the timing advance with a periodicity being less than 1 ms, less than 900 ms, preferably less than 700 ms or even less than 500 ms. Combinations of such solutions may be used.
  • Aspects of the present invention relate to signalling of TDD slot configurations when the UE is connected to different orbits to arrive at an inter-orbit configuration signalling. The signalling may be provided by a selected orbit or by each of the orbits.
  • Embodiments of the present invention may be used to define parts of a technical standard, e.g., through 3GPP SA 2, RAN 1 , RAN 2, RAN 4 or RAN 5.
  • a technical standard e.g., through 3GPP SA 2, RAN 1 , RAN 2, RAN 4 or RAN 5.
  • the described embodiments relate to a TDD operation in NTN. In some situations, it may happen that the UEs already transmit whilst there is still transmitted in DL. This may benefit from a network that knows where the terminals are located to avoid a schedule of DL traffic when the UE has started to send and is, therefore, unable to receive. Embodiments allow to avoid TDD duplex-gaps or, the other way around, those S-slots are used to allocate traffic.
  • the following solutions address at least one of the problems identified when operation a sat communication system in low earth orbit with satellites flying over the users to be served at high speed with varying distance between the UE and the satellite, wherein the satellite communication system is considered to operate in TDD mode and the invention describes techniques to handle the long and varying distance and RTT between the satellite and the UEs.
  • the gNB could allocate different frame structures for the UEs based on their distances from the satellite/gNB.
  • the new frame structure configurations include a number of DL slots, a number of UL slots, and a number of special slots (S-slots). Additionally, the special slots granularity could be on OFDM symbols-basis. So, a special slot within the frame structure might have newly configured symbols within the special slot, which includes DL OFDM symbols, UL OFDM symbols, and OFDM guard symbols.
  • the frame length may be extended for those UEs (increasing the number of DL slots as well as UL slots).
  • the absolute frame length may be a function of the RTT and can be configured for:
  • a list of frame structure configurations may be defined and broadcasted to several or all UEs.
  • the gNB may instruct the UEs within a cel l/beam/g roup to activate a certain frame structure, e.g., based on their distances from the gNB/satellite either implicitly or explicitly.
  • • UEs group allocation may change over time, e.g., during flight of satellite
  • slot/frame structure may follow a longest delay of a user in a cell and is fixed over time
  • a slot structure may follow the longest delay in the cell and can be reduced over the time the satellite is serving the cell (e.g., LEO 600km-2.000km)
  • NTN non-terrestrial network
  • the satellite is orbiting the Earth at an angular speed of rotation much greater than one Earth day, the position of the satellite in the sky when observed from a fixed point on Earth will change as a function of time.
  • the sub-figure thus shows what could be called a snapshot of the orbiting satellite.
  • the UEs position on Earth or above Earth e.g.
  • a slot structure 502 which is comprised of downlink (DL) slots, uplink (UL) slots and flexible or soft slots (S).
  • DL downlink
  • UL uplink
  • S flexible or soft slots
  • All slot structures are drawn with reference to the same absolute time axis, running from left to right in the x-axis.
  • TDD time division duplex
  • the soft slots contained within the slot structure can therefore either be used for the purpose of UL or the purpose of DL communication and are used on a UE-by-UE basis and according to the distance of a UE from the gNB. The assignment of the soft slots and the associated signalling is discussed elsewhere.
  • the soft slots can also be unused, i.e., neither used for uplink nor for downlink.
  • the duration of each slot in the slot structure is fixed, the number of slots assigned to soft slots (between blocks of DL and UL slots) determines the longest delay that can be accommodated within the overall slot structure. This can either be fixed during the time the gNB is serving the UEs in its cell or can be reduced over time. The latter is possible due to the changing elevation angle experienced by each UE.
  • the S-slots (S) are to be used to compensate for the access delay due to the large distance using the mechanism of timing advance (TA). Therefore, only a subset of the S-slots is available for a particular UE at a particular time to be used in DL or UL direction. Assuming that the gNB is aware about the S-slots available/accessible for a particular UE at a particular point/period of time the gNB can schedule additional DL or UL traffic for this UE into such S-slots, therefore effectively increasing the utilization of the available radio resources.
  • TA timing advance
  • the gNB can schedule user plane traffic for such UE and signal the allocated S-slot numbers to the UE.
  • the same principle can be applied to a multitude of UEs, which can be grouped into a scheduled set of UEs served by the gNB in particular S-slots in DI or UL direction.
  • the associated signalling can be done individually per UE or for a group of UEs using e.g. a group identifier.
  • the knowledge about the flight path of the satellite can be further included into the solution allowing to further reduce the signalling overhead to the UEs or group of UEs.
  • the RTT and resulting available/accessible S-slots can be precomputed at the gNB and/or the UEs side.
  • a resulting sequence of available /accessible S-slots can be determined and applied for further utilization of the S-slots in DL or UL direction.
  • the sequence of S-slots can be determined at both end independently and used or in line with the usual resource allocation procedure provided by the gNB to the UE by configuration. Or by the UE to the gNB e.g. by a measurement report.
  • sequence may be location dependent therefore different UEs in cell may experience a different sequence of available/accessible S-slots. Nevertheless, particular UEs can be grouped sharing the same sequence of S-slots.
  • T o further reduce signalling overhead
  • particular sequences of available/accessible S-slots can be put into sets, wherein such sets can be signalled/configured using a set identifier for configuration overhead reduction.
  • certain S-slots can be used for transmission to and reception from UEs simultaneously.
  • An easy to implement variant of such advance duplexing scheme would be the use of subband full duplex, wherein a frequency part of the S-slot is used in DL direction while another frequency part of the spectrum is used in UL direction.
  • the inventors therefore propose to allow for the simultaneous assignment of particular s-slots to be used in DL and UL direction simultaneously wherein some UE or group of UEs are served in DL direction while other UEs or group of UEs use resources of the same S-slot for UL transmission.
  • the UEs can operate in simple TDD fashion without any advanced duplex capability.
  • the S-slots have to be configured by the gNB using further usage describing identification e.g. S-slot operated in SBFD mode or symbols operated in SBFD mode.
  • the partitioning of the S-slot for simultaneous UL and DL usage within one S-slot can be done in an overlapping or not-overlapping fashion over the frequency domain (subbands), the time domain (OFDM symbols) or combinations thereof.
  • a small NR cell with one-to-one mapping between the NR cell, satellite beam, and NR beam (SSB).
  • SSB NR beam
  • a large NR cell with one-to-one mapping between the NR cell, satellite beam, and NR beam (SSB).
  • SSB NR beam
  • a large NR cell with one-to-one mapping between the NR cell and the satellite beam, but multiple NR beams (SSBs) within the NR cell.
  • SSBs NR beams
  • a large NR cell with one-to-many mapping between the NR cell and the satellite beams.
  • a one-to-one mapping could be assumed between the satellite beam and the NR beam (SSB).
  • the management of the frame structure depends on which option to be considered:
  • the differential delay within the cell is small and can be compensated with one frame structure reflecting the largest distance within the cell. In this option, all UEs within the cell would be allocated the same frame structure.
  • the gNB In the idle mode (RRCJDLE), the gNB broadcasts a list of frame structure configurations using system information messages such as SIB1 , SIB19 for NR-NTN, and SIB31 for loT-NTN. The gNB keeps updating the list of frame structure using the periodic SIB1 , SIB19, or SIB31.
  • the gNB could update the list of frame structures using SIB messages since they are common for all UEs within a beam/cell/group. Additionally, gNB could update the list of frame structures using dedicated RRC-messages if necessary. As the satellite moves, the elevation angle of satellite beam covering the NR cell changes, which leads to a change in the largest distance in the cell. In this case, gNB could update the list of frame structure if necessary and indicates the UEs either explicitly or implicitly to update their frame structure within the cell using either DCI in the PDCCH or MAC-CE in the PDSCH. Explicit indication might be in the form of an explicit indication by the gNB to which frame structure the UEs could use.
  • An implicit indication might be in the form of an implicit indication of which frame structure the UEs should use by instructing the UEs within a certain time/location/group to change their frame structure after a certain time due to the mobility of the satellite.
  • Time-based trigger is preferred due the fixed earth cell.
  • location-based trigger should not be excluded.
  • option 2 the same as option 1 could be used, which might have negative impact on UEs within the cell due to the large differential delay within the cell.
  • the gNB might group the UEs based on their serving NR beam (SSB) within the satellite beam/NR cell.
  • SSB serving NR beam
  • the gNB would be able to transmit the list of frame structures and to instruct the UEs within that NR beam to use a certain frame structure.
  • the list of frame structure could be broadcasted in SIB messages in RRCJDLE and RRC_ACTIVE modes on an SSB-basis and transmitted in a dedicated manner to certain UEs using RRC messages in RRC_ACTIVE mode.
  • DCI in PDCCH and MAC CE in PDSCH might be used to activate a certain frame structure.
  • the grouping of users is based on their serving satellite beam, so all UEs served by the same satellite beam are going to use the same frame structure.
  • the gNB broadcasts the list of frame structures using system information messages for all UEs in RRCJDLE and RRC_ACTIVE on a satellite-beam basis. Periodic transmission of SIB messages is used to periodically update the list of frame structures if necessary (as for other options). Additionally, the gNB is able to update the list using RRC_messages in a dedicated manner for UEs in RRC_ACTIVE. Activating/deactivating a certain frame structure is done as previously mentioned.
  • Grouping the UEs based on their serving NR beam (SSB) or serving satellite beam facilitates the classifications of UEs, as the gNB does not necessarily need an exact information of the position/distance of the UE from the gNB/satellite. All UEs served by the same NR beam or satellite beam may also be allocated the same frame structure.
  • SSB serving NR beam
  • All UEs served by the same NR beam or satellite beam may also be allocated the same frame structure.
  • Another possible approach in case of a large cell is to rely on the reported TA by the UE to estimate their distance and RTT from the satellite/gNB.
  • the gNB may classify the UEs into contours (groups) based on their distances.
  • a feeder-link switch-over might occur, which triggers an update of the frame structure.
  • the gNB should update the frame structure in case of a feeder-link switch if necessary, even if the service link delay didn’t change significantly to trigger a frame structure update.
  • an ISL changeover between the serving satellite and the relying satellite/satellites triggers a change in the distances of the UEs back to the gNB.
  • the gNB should trigger a frame structure update.
  • the defined frame structures should be exchanged between neighbouring satellites/gNBs over the ISL/Xn and NG for NR-NTN/X2 and S1 for loT-NTN. This may be used for satellites/gNBs, which are going to cover the same geographical area on the ground/ the same beam/the same cell. This may be used in case of a satellite/gNB switch/handover, where the UE needs to establish an RRC connection with the target gNB before receiving RRC reconfiguration message updating the list of frame structures or instructing the UE to use a specific frame structure. Alternatively or in addition, the source gNB/satellite may be able to forward this information from the target satellite/gNB to the UE before completing a handover/switchover.
  • the gNB may be configured to flexibly allocate OFDM symbols within the special slots for DL/UL in order to increase the resource allocation efficiency, and this requires a good alignment between the gNB and UE on the actual value of TA applied by the UE. Increasing the periodicity of TA reporting and the granularity of reporting below 1 ms may be required.
  • codeword could be distributed across several slots.
  • user data and control channel data is mapped within the frame structure usually bounded or constraint to a slot or a subset of it, e.g. several OFDM symbols.
  • such information is usually segmented into a sequence of bits which will be encoded, rate matched and modulated before being mapped onto a set of allocated RBs which are then signalled e.g. via a coreset to the UE.
  • RBs are distributed, for ease of operation usually within one slot or under certain configurations across consecutive slots.
  • the RTT will cause, depending on distance between the satellite and the UE, that the UE will start UL transmissions using a suitable TA to have all UL signals arrive in time at the gNB within the given slot structure.
  • certain S-slots which contain user plane data can’t be used for reception of transmission of particular UEs due to the TA which requires exemption of certain OFDM symbols of such S-slots.
  • all affected slots have to be vacated for DL or UL traffic to such UEs, causing a significant waste of DL or UL resources to be used.
  • the inventors identified a solution to use parts or slots in an efficient manner, by mapping the user plane traffic in a novel manner.
  • implantation options are given some of the implantation options proposed:
  • the user plane data may be mapped only accessible RBs of an S-slot (accessible means the UE is able to transmit or receive particular OFDM symbols in TDD mode
  • the code word may be mapped on to a subset of OFDM symbols of one s-Slot
  • the code word may be mapped on to a subset of OFDM symbols of one s-Slot and a subset of OFDM symbols of a consecutive s-lot, thus “violating” the usual boundary of an S-slot for mapping of the code word
  • the loss of a complete set of resources within an S-slot could be compensated by an adaptation of the coding level matched to the loss of usable OFDM symbols within a slot.
  • Various elements and features of the present invention may be implemented in hardware using analogue and/or digital circuits, in software, through the execution of instructions by one or more general purpose or special-purpose processors, or as a combination of hardware and software.
  • embodiments of the present invention may be implemented in the environment of a computer system or another processing system.
  • Fig. 6 illustrates an example of a computer system 600.
  • the units or modules as well as the steps of the methods performed by these units may execute on one or more computer systems 600.
  • the computer system 600 includes one or more processors 602, like a special purpose or a general-purpose digital signal processor.
  • the processor 602 is connected to a communication infrastructure 604, like a bus or a network.
  • the computer system 600 includes a main memory 606, e.g., a random-access memory (RAM), and a secondary memory 608, e.g., a hard disk drive and/or a removable storage drive.
  • the secondary memory 608 may allow computer programs or other instructions to be loaded into the computer system 600.
  • the computer system 600 may further include a communications interface 610 to allow software and data to be transferred between computer system 600 and external devices.
  • the communication may be in the form of electronic, electromagnetic, optical, or other signals capable of being handled by a communications interface.
  • the communication may use a wire or a cable, fibre optics, a phone line, a cellular phone link, an RF link and other communications channels 612.
  • computer program medium and “computer readable medium” are used to generally refer to tangible storage media such as removable storage units or a hard disk installed in a hard disk drive. These computer program products are means for providing software to the computer system 600.
  • the computer programs also referred to as computer control logic, are stored in main memory 606 and/or secondary memory 608. Computer programs may also be received via the communications interface 610.
  • the computer program when executed, enables the computer system 600 to implement the present invention.
  • the computer program when executed, enables processor 602 to implement the processes of the present invention, such as any of the methods described herein. Accordingly, such a computer program may represent a controller of the computer system 600.
  • the software may be stored in a computer program product and loaded into computer system 600 using a removable storage drive, an interface, like communications interface 610.
  • the implementation in hardware or in software may be performed using a digital storage medium, for example cloud storage, a floppy disk, a DVD, a Blue-Ray, a CD, a ROM, a PROM, an EPROM, an EEPROM or a FLASH memory, having electronically readable control signals stored thereon, which cooperate (or are capable of cooperating) with a programmable computer system such that the respective method is performed. Therefore, the digital storage medium may be computer readable.
  • a digital storage medium for example cloud storage, a floppy disk, a DVD, a Blue-Ray, a CD, a ROM, a PROM, an EPROM, an EEPROM or a FLASH memory, having electronically readable control signals stored thereon, which cooperate (or are capable of cooperating) with a programmable computer system such that the respective method is performed. Therefore, the digital storage medium may be computer readable.
  • Some embodiments according to the invention comprise a data carrier having electronically readable control signals, which are capable of cooperating with a programmable computer system, such that one of the methods described herein is performed.
  • embodiments of the present invention may be implemented as a computer program product with a program code, the program code being operative for performing one of the methods when the computer program product runs on a computer.
  • the program code may for example be stored on a machine-readable carrier.
  • Other embodiments comprise the computer program for performing one of the methods described herein, stored on a machine-readable carrier.
  • an embodiment of the inventive method is, therefore, a computer program having a program code for performing one of the methods described herein, when the computer program runs on a computer.
  • a further embodiment of the inventive methods is, therefore, a data carrier (or a digital storage medium, or a computer-readable medium) comprising, recorded thereon, the computer program for performing one of the methods described herein.
  • a further embodiment of the inventive method is, therefore, a data stream or a sequence of signals representing the computer program for performing one of the methods described herein. The data stream or the sequence of signals may for example be configured to be transferred via a data communication connection, for example via the Internet.
  • a further embodiment comprises a processing means, for example a computer, or a programmable logic device, configured to or adapted to perform one of the methods described herein.
  • a further embodiment comprises a computer having installed thereon the computer program for performing one of the methods described herein.
  • a programmable logic device for example a field programmable gate array
  • a field programmable gate array may cooperate with a microprocessor in order to perform one of the methods described herein.
  • the methods are preferably performed by any hardware apparatus.

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Abstract

Un équipement utilisateur (UE) comprend une interface sans fil pour recevoir des signaux sans fil et pour transmettre des signaux sans fil. L'UE est conçu pour fonctionner dans une cellule d'un réseau de communication sans fil selon un schéma de duplexage par répartition dans le temps (TDD) qui comprend une pluralité de trames TDD, chaque trame TDD comprenant une pluralité de créneaux agencés selon une structure de trame, la pluralité de créneaux comprenant un premier nombre de créneaux de liaison descendante (DL), un deuxième nombre de créneaux de liaison montante (UL), et un troisième nombre de créneaux spéciaux (S), par exemple, agencés entre le premier nombre de créneaux UL et le deuxième nombre de créneaux UL. L'UE est conçu pour fonctionner avec une structure de trame efficace variable dans le schéma TDD pour compenser des distances variables entre l'UE et une station de base actionnant la cellule.
PCT/EP2025/065890 2024-06-07 2025-06-06 Procédé de fonctionnement tdd efficace dans un ntn Pending WO2025252995A1 (fr)

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Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20220182194A1 (en) * 2019-03-01 2022-06-09 Telefónica, S.A Method and device for minimizing interferences between tdd communications networks
WO2024171135A1 (fr) * 2023-02-17 2024-08-22 Telefonaktiebolaget Lm Ericsson (Publ) Systèmes et procédés pour l'optimisation de l'utilisation de créneau duplex à répartition dans le temps pour air-sol

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20220182194A1 (en) * 2019-03-01 2022-06-09 Telefónica, S.A Method and device for minimizing interferences between tdd communications networks
WO2024171135A1 (fr) * 2023-02-17 2024-08-22 Telefonaktiebolaget Lm Ericsson (Publ) Systèmes et procédés pour l'optimisation de l'utilisation de créneau duplex à répartition dans le temps pour air-sol

Non-Patent Citations (3)

* Cited by examiner, † Cited by third party
Title
MAGNUS LARSSON ET AL: "On TDD in large ATG cells", vol. RAN WG4, no. Toulouse, FR; 20230821 - 20230825, 11 August 2023 (2023-08-11), XP052447479, Retrieved from the Internet <URL:https://www.3gpp.org/ftp/TSG_RAN/WG4_Radio/TSGR4_108/Docs/R4-2313204.zip R4-2313204.docx> [retrieved on 20230811] *
PRASHANT SHARMA ET AL: "RRM requirements for R18 ATG UEs", vol. RAN WG4, no. Toulouse, FR; 20230821 - 20230825, 11 August 2023 (2023-08-11), XP052447905, Retrieved from the Internet <URL:https://www.3gpp.org/ftp/TSG_RAN/WG4_Radio/TSGR4_108/Docs/R4-2313710.zip R4-2313710 RRM requirements for R18 ATG UEs.docx> [retrieved on 20230811] *
RAFHAEL AMORIM ET AL: "Discussion on ATG Timing Requirements", vol. RAN WG4, no. Online; 20230417 - 20230426, 10 April 2023 (2023-04-10), XP052285710, Retrieved from the Internet <URL:https://www.3gpp.org/ftp/TSG_RAN/WG4_Radio/TSGR4_106bis-e/Docs/R4-2304499.zip R4-2304499.docx> [retrieved on 20230410] *

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