WO2022052099A1 - Mise à jour de précodeurs dans des communications duplex à répartition en fréquence - Google Patents

Mise à jour de précodeurs dans des communications duplex à répartition en fréquence Download PDF

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Publication number
WO2022052099A1
WO2022052099A1 PCT/CN2020/115040 CN2020115040W WO2022052099A1 WO 2022052099 A1 WO2022052099 A1 WO 2022052099A1 CN 2020115040 W CN2020115040 W CN 2020115040W WO 2022052099 A1 WO2022052099 A1 WO 2022052099A1
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WIPO (PCT)
Prior art keywords
measurements
precoder
csi
vectors
group
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PCT/CN2020/115040
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English (en)
Inventor
Rui Hu
Liangming WU
Chenxi HAO
Yu Zhang
Chao Wei
Hao Xu
Wei XI
Qiaoyu Li
Min Huang
Kangqi LIU
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Qualcomm Incorporated
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Priority to PCT/CN2020/115040 priority Critical patent/WO2022052099A1/fr
Publication of WO2022052099A1 publication Critical patent/WO2022052099A1/fr

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B7/00—Radio transmission systems, i.e. using radiation field
    • H04B7/02—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas
    • H04B7/04—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas
    • H04B7/0413—MIMO systems
    • H04B7/0456—Selection of precoding matrices or codebooks, e.g. using matrices antenna weighting
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B7/00—Radio transmission systems, i.e. using radiation field
    • H04B7/02—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas
    • H04B7/04—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas
    • H04B7/06—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station
    • H04B7/0613—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station using simultaneous transmission
    • H04B7/0615—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station using simultaneous transmission of weighted versions of same signal
    • H04B7/0619—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station using simultaneous transmission of weighted versions of same signal using feedback from receiving side
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L25/00—Baseband systems
    • H04L25/02—Details ; arrangements for supplying electrical power along data transmission lines
    • H04L25/0202—Channel estimation
    • H04L25/0204—Channel estimation of multiple channels
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L25/00—Baseband systems
    • H04L25/02—Details ; arrangements for supplying electrical power along data transmission lines
    • H04L25/0202—Channel estimation
    • H04L25/0224—Channel estimation using sounding signals

Definitions

  • aspects of the present disclosure relate to wireless communications, and more particularly, to techniques for updating precoders in frequency division duplex (FDD) communications systems.
  • FDD frequency division duplex
  • multiple-access systems examples include 3rd Generation Partnership Project (3GPP) Long Term Evolution (LTE) systems, LTE Advanced (LTE-A) systems, code division multiple access (CDMA) systems, time division multiple access (TDMA) systems, frequency division multiple access (FDMA) systems, orthogonal frequency division multiple access (OFDMA) systems, single-carrier frequency division multiple access (SC-FDMA) systems, and time division synchronous code division multiple access (TD-SCDMA) systems, to name a few.
  • 3GPP 3rd Generation Partnership Project
  • LTE Long Term Evolution
  • LTE-A LTE Advanced
  • CDMA code division multiple access
  • TDMA time division multiple access
  • FDMA frequency division multiple access
  • OFDMA orthogonal frequency division multiple access
  • SC-FDMA single-carrier frequency division multiple access
  • TD-SCDMA time division synchronous code division multiple access
  • New radio e.g., 5G NR
  • 5G NR is an example of an emerging telecommunication standard.
  • NR is a set of enhancements to the LTE mobile standard promulgated by 3GPP.
  • NR is designed to better support mobile broadband Internet access by improving spectral efficiency, lowering costs, improving services, making use of new spectrum, and better integrating with other open standards using OFDMA with a cyclic prefix (CP) on the downlink (DL) and on the uplink (UL) .
  • CP cyclic prefix
  • NR supports beamforming, multiple-input multiple-output (MIMO) antenna technology, and carrier aggregation.
  • MIMO multiple-input multiple-output
  • the method generally includes receiving a first signal, wherein the first signal is transmitted by a base station (BS) using a first precoder; determining measurements of a propagation channel based on the first signal; and transmitting the measurements to the BS.
  • BS base station
  • the method generally includes transmitting, using a first precoder, a first signal to a user equipment (UE) ; receiving, from the UE, measurements of a propagation channel determined by the UE based on the first signal; and determining a second precoder based on the first precoder and the measurements.
  • BS base station
  • the method generally includes transmitting, using a first precoder, a first signal to a user equipment (UE) ; receiving, from the UE, measurements of a propagation channel determined by the UE based on the first signal; and determining a second precoder based on the first precoder and the measurements.
  • UE user equipment
  • aspects of the present disclosure provide means for, apparatus, processors, and computer-readable mediums for performing the methods described herein.
  • FIG. 1 is a block diagram conceptually illustrating an example wireless communication network, in accordance with certain aspects of the present disclosure.
  • FIG. 2 is a block diagram conceptually illustrating a design of an example a base station (BS) and user equipment (UE) , in accordance with certain aspects of the present disclosure.
  • BS base station
  • UE user equipment
  • FIG. 3 is an example frame format for certain wireless communication systems (e.g., new radio (NR) ) , in accordance with certain aspects of the present disclosure.
  • NR new radio
  • FIG. 4 is an exemplary transmission timeline for updating a downlink (DL) precoder, in accordance with aspects of the present disclosure.
  • FIG. 5 is an exemplary transmission timeline of a UE providing periodic channel feedback for updating a DL precoder, in accordance with aspects of the present disclosure.
  • FIG. 8 is a flow diagram illustrating example operations for wireless communication by a BS, in accordance with certain aspects of the present disclosure.
  • FIG. 10 illustrates a communications device that may include various components configured to perform operations for the techniques disclosed herein in accordance with aspects of the present disclosure.
  • aspects of the present disclosure provide apparatus, methods, processing systems, and computer readable mediums for updating precoders in frequency division duplex (FDD) communications systems.
  • FDD frequency division duplex
  • a transmitter e.g., a base station (BS)
  • a receiver e.g., a user equipment (UE)
  • UE user equipment
  • a transmitter e.g., in a BS
  • Such a matrix of values may be referred to as a precoder.
  • a precoder may be derived based on measured channel conditions (e.g., by measuring a reference signal (RS) at a receiver) .
  • RS reference signal
  • downlink (DL) and uplink (DL) channels may have correlated parameters, e.g., delay spread, angular spread, shadowing factor, cluster delay, cluster power, and departure/arrival angles.
  • the DL and UL channels may have correlated spatial domain (SD) and frequency domain (FD) bases.
  • a BS (e.g., a next generation NodeB (gNB) ) generates precoders for both the SD and FD, e.g., SD and FD precoders can be generated based on SD and FD bases, and the BS applies both precoders when transmitting.
  • SD and FD bases can be generated based on the estimated UL channel by utilizing FDD reciprocity. That is, a BS may receive an UL transmission (e.g., a reference signal) , estimate the UL channel, and then generate SD and FD bases for the DL channel based on the estimated UL channel.
  • an UL transmission e.g., a reference signal
  • UL and DL channels may sometimes have poor reciprocity, and thus generating SD and FD bases for the DL channel based on the estimated UL channel may result in poor performance of a DL precoder based on those SD and FD bases.
  • Techniques for updating those DL precoders may improve the performance of the DL precoders and the performance of the wireless communications system.
  • any number of wireless networks may be deployed in a given geographic area.
  • Each wireless network may support a particular radio access technology (RAT) and may operate on one or more frequencies.
  • RAT may also be referred to as a radio technology, an air interface, etc.
  • a frequency may also be referred to as a carrier, a subcarrier, a frequency channel, a tone, a subband, etc.
  • Each frequency may support a single RAT in a given geographic area in order to avoid interference between wireless networks of different RATs.
  • NR access may support various wireless communication services, such as enhanced mobile broadband (eMBB) targeting wide bandwidth (e.g., 80 MHz or beyond) , millimeter wave (mmW) targeting high carrier frequency (e.g., e.g., 24 GHz to 53 GHz or beyond) , massive machine type communications MTC (mMTC) targeting non-backward compatible MTC techniques, and/or mission critical targeting ultra-reliable low-latency communications (URLLC) .
  • eMBB enhanced mobile broadband
  • mmW millimeter wave
  • mMTC massive machine type communications MTC
  • URLLC ultra-reliable low-latency communications
  • These services may include latency and reliability requirements.
  • These services may also have different transmission time intervals (TTI) to meet respective quality of service (QoS) requirements.
  • TTI transmission time intervals
  • QoS quality of service
  • these services may co-exist in the same subframe.
  • NR supports beamforming and beam direction may be dynamically configured.
  • MIMO transmissions with precoding may also be supported.
  • MIMO configurations in the DL may support up to 8 transmit antennas with multi-layer DL transmissions up to 8 streams and up to 2 streams per UE.
  • Multi-layer transmissions with up to 2 streams per UE may be supported.
  • Aggregation of multiple cells may be supported with up to 8 serving cells.
  • the BSs 110 and UEs 120 may be configured for updating precoders in frequency division duplex (FDD) communications systems.
  • the BS 110a includes a precoder manager 112 that transmits, using a first precoder, a first signal to a user equipment (UE, e.g., UE 120a) ; receives, from the UE, measurements of a propagation channel determined by the UE based on the first signal; and determines a second precoder based on the first precoder and the measurements, in accordance with aspects of the present disclosure.
  • the UE 120a includes a channel feedback manager 122 that receives a first signal, wherein the first signal is transmitted by a base station (BS, e.g. BS 110a) using a first precoder; determines first measurements of a propagation channel based on the first signal; and transmits the first measurements to the BS, in accordance with aspects of the present disclosure.
  • BS base station
  • the wireless communication network 100 may include a number of BSs 110a-z (each also individually referred to herein as BS 110 or collectively as BSs 110) and other network entities.
  • a BS 110 may provide communication coverage for a particular geographic area, sometimes referred to as a “cell” , which may be stationary or may move according to the location of a mobile BS 110.
  • the BSs 110 may be interconnected to one another and/or to one or more other BSs or network nodes (not shown) in wireless communication network 100 through various types of backhaul interfaces (e.g., a direct physical connection, a wireless connection, a virtual network, or the like) using any suitable transport network.
  • backhaul interfaces e.g., a direct physical connection, a wireless connection, a virtual network, or the like
  • the BSs 110a, 110b and 110c may be macro BSs for the macro cells 102a, 102b and 102c, respectively.
  • the BS 110x may be a pico BS for a pico cell 102x.
  • the BSs 110y and 110z may be femto BSs for the femto cells 102y and 102z, respectively.
  • a BS may support one or multiple cells.
  • the BSs 110 communicate with UEs 120a-y (each also individually referred to herein as UE 120 or collectively as UEs 120) in the wireless communication network 100.
  • the UEs 120 (e.g., 120x, 120y, etc. ) may be dispersed throughout the wireless communication network 100, and each UE 120 may be stationary or mobile.
  • Wireless communication network 100 may also include relay stations (e.g., relay station 110r) , also referred to as relays or the like, that receive a transmission of data and/or other information from an upstream station (e.g., a BS 110a or a UE 120r) and sends a transmission of the data and/or other information to a downstream station (e.g., a UE 120 or a BS 110) , or that relays transmissions between UEs 120, to facilitate communication between devices.
  • relay stations e.g., relay station 110r
  • relays or the like that receive a transmission of data and/or other information from an upstream station (e.g., a BS 110a or a UE 120r) and sends a transmission of the data and/or other information to a downstream station (e.g., a UE 120 or a BS 110) , or that relays transmissions between UEs 120, to facilitate communication between devices.
  • Anetwork controller 130 may be in communication with a set of BSs 110 and provide coordination and control for these BSs 110 (e.g., via a backhaul) .
  • the network controller 130 may be in communication with a core network 132 (e.g., a 5G Core Network (5GC) ) , which provides various network functions such as Access and Mobility Management, Session Management, User Plane Function, Policy Control Function, Authentication Server Function, Unified Data Management, Application Function, Network Exposure Function, Network Repository Function, Network Slice Selection Function, etc.
  • a core network 132 e.g., a 5G Core Network (5GC)
  • 5GC 5G Core Network
  • FIG. 2 illustrates example components of BS 110a and UE 120a (e.g., the wireless communication network 100 of FIG. 1) , which may be used to implement aspects of the present disclosure.
  • a transmit processor 220 may receive data from a data source 212 and control information from a controller/processor 240.
  • the control information may be for the physical broadcast channel (PBCH) , physical control format indicator channel (PCFICH) , physical hybrid ARQ indicator channel (PHICH) , physical downlink control channel (PDCCH) , group common PDCCH (GC PDCCH) , etc.
  • the data may be for the physical downlink shared channel (PDSCH) , etc.
  • a medium access control (MAC) -control element (MAC-CE) is a MAC layer communication structure that may be used for control command exchange between wireless nodes.
  • the MAC-CE may be carried in a shared channel such as a physical downlink shared channel (PDSCH) , a physical uplink shared channel (PUSCH) , or a physical sidelink shared channel (PSSCH) .
  • PDSCH physical downlink shared channel
  • PUSCH physical uplink shared channel
  • PSSCH physical sidelink shared channel
  • the processor 220 may process (e.g., encode and symbol map) the data and control information to obtain data symbols and control symbols, respectively.
  • the transmit processor 220 may also generate reference symbols, such as for the primary synchronization signal (PSS) , secondary synchronization signal (SSS) , PBCH demodulation reference signal (DMRS) , and channel state information reference signal (CSI-RS) .
  • PSS primary synchronization signal
  • SSS secondary synchronization signal
  • DMRS PBCH demodulation reference signal
  • CSI-RS channel state information reference signal
  • a transmit (TX) multiple-input multiple-output (MIMO) processor 230 may perform spatial processing (e.g., precoding) on the data symbols, the control symbols, and/or the reference symbols, if applicable, and may provide output symbol streams to the modulators (MODs) 232a-232t.
  • MIMO modulation reference signal
  • Each modulator 232 may process a respective output symbol stream (e.g., for OFDM, etc. ) to obtain an output sample stream. Each modulator may further process (e.g., convert to analog, amplify, filter, and upconvert) the output sample stream to obtain a downlink signal. Downlink signals from modulators 232a-232t may be transmitted via the antennas 234a-234t, respectively.
  • a respective output symbol stream e.g., for OFDM, etc.
  • Each modulator may further process (e.g., convert to analog, amplify, filter, and upconvert) the output sample stream to obtain a downlink signal.
  • Downlink signals from modulators 232a-232t may be transmitted via the antennas 234a-234t, respectively.
  • the antennas 252a-252r may receive the downlink signals from the BS 110a and may provide received signals to the demodulators (DEMODs) in transceivers 254a-254r, respectively.
  • Each demodulator 254 may condition (e.g., filter, amplify, downconvert, and digitize) a respective received signal to obtain input samples.
  • Each demodulator may further process the input samples (e.g., for OFDM, etc. ) to obtain received symbols.
  • a MIMO detector 256 may obtain received symbols from all the demodulators 254a-254r, perform MIMO detection on the received symbols if applicable, and provide detected symbols.
  • a receive processor 258 may process (e.g., demodulate, deinterleave, and decode) the detected symbols, provide decoded data for the UE 120a to a data sink 260, and provide decoded control information to a controller/processor 280.
  • a transmit processor 264 may receive and process data (e.g., for the physical uplink shared channel (PUSCH) ) from a data source 262 and control information (e.g., for the physical uplink control channel (PUCCH) from the controller/processor 280.
  • the transmit processor 264 may also generate reference symbols for a reference signal (e.g., for the sounding reference signal (SRS) ) .
  • the symbols from the transmit processor 264 may be precoded by a TX MIMO processor 266 if applicable, further processed by the modulators in transceivers 254a-254r (e.g., for SC-FDM, etc. ) , and transmitted to the BS 110a.
  • the uplink signals from the UE 120a may be received by the antennas 234, processed by the modulators 232, detected by a MIMO detector 236 if applicable, and further processed by a receive processor 238 to obtain decoded data and control information sent by the UE 120a.
  • the receive processor 238 may provide the decoded data to a data sink 239 and the decoded control information to the controller/processor 240.
  • the memories 242 and 282 may store data and program codes for BS 110a and UE 120a, respectively.
  • a scheduler 244 may schedule UEs for data transmission on the downlink and/or uplink.
  • Antennas 252, processors 266, 258, 264, and/or controller/processor 280 of the UE 120a and/or antennas 234, processors 220, 230, 238, and/or controller/processor 240 of the BS 110a may be used to perform the various techniques and methods described herein. For example, as shown in FIG.
  • the controller/processor 240 of the BS 110a has a precoder manager 241 that transmits, using a first precoder, a first signal to a user equipment (UE, e.g., UE 120a) ; receives, from the UE, measurements of a propagation channel determined by the UE based on the first signal; and determines a second precoder based on the first precoder and the measurements, according to aspects described herein.
  • the controller/processor 280 of the UE 120a has an channel feedback manager 281 that receives a first signal, wherein the first signal is transmitted by a base station (BS, e.g.
  • BS base station
  • BS 110a using a first precoder; determines first measurements of a propagation channel based on the first signal; and transmits the first measurements to the BS, according to aspects described herein.
  • controller/processor other components of the UE 120a and BS 110a may be used to perform the operations described herein.
  • NR may utilize orthogonal frequency division multiplexing (OFDM) with a cyclic prefix (CP) on the uplink and downlink.
  • OFDM orthogonal frequency division multiplexing
  • CP cyclic prefix
  • NR may support half-duplex operation using time division duplexing (TDD) .
  • OFDM and single-carrier frequency division multiplexing (SC-FDM) partition the system bandwidth into multiple orthogonal subcarriers, which are also commonly referred to as tones, bins, etc. Each subcarrier may be modulated with data. Modulation symbols may be sent in the frequency domain with OFDM and in the time domain with SC-FDM.
  • the spacing between adjacent subcarriers may be fixed, and the total number of subcarriers may be dependent on the system bandwidth.
  • the minimum resource allocation may be 12 consecutive subcarriers.
  • the system bandwidth may also be partitioned into subbands. For example, a subband may cover multiple RBs.
  • NR may support a base subcarrier spacing (SCS) of 15 KHz and other SCS may be defined with respect to the base SCS (e.g., 30 kHz, 60 kHz, 120 kHz, 240 kHz, etc. ) .
  • SCS base subcarrier spacing
  • FIG. 3 is a diagram showing an example of a frame format 300 for NR.
  • the transmission timeline for each of the downlink and uplink may be partitioned into units of radio frames.
  • Each radio frame may have a predetermined duration (e.g., 10 ms) and may be partitioned into 10 subframes, each of 1 ms, with indices of 0 through 9.
  • Each subframe may include a variable number of slots (e.g., 1, 2, 4, 8, 16, ...slots) depending on the SCS.
  • Each slot may include a variable number of symbol periods (e.g., 7, 12, or 14 symbols) depending on the SCS.
  • the symbol periods in each slot may be assigned indices.
  • a mini-slot which may be referred to as a sub-slot structure, refers to a transmit time interval having a duration less than a slot (e.g., 2, 3, or 4 symbols) .
  • Each symbol in a slot may indicate a link direction (e.g., DL, UL, or flexible) for data transmission and the link direction for each subframe may be dynamically switched.
  • the link directions may be based on the slot format.
  • Each slot may include DL/UL data as well as DL/UL control information.
  • a synchronization signal block is transmitted.
  • SSBs may be transmitted in a burst where each SSB in the burst corresponds to a different beam direction for UE-side beam management (e.g., including beam selection and/or beam refinement) .
  • the SSB includes a PSS, a SSS, and a two symbol PBCH.
  • the SSB can be transmitted in a fixed slot location, such as the symbols 0-3 as shown in FIG. 3.
  • the PSS and SSS may be used by UEs for cell search and acquisition.
  • the PSS may provide half-frame timing, the SS may provide the CP length and frame timing.
  • the PSS and SSS may provide the cell identity.
  • a transmitter when transmitting a signal wirelessly, a transmitter (e.g., in a BS) may apply a precoder while generating a signal in order to compensate for channel conditions between the transmitter and the receiver.
  • a DL precoder may be derived based on measured UL channel conditions (e.g., in an FDD communications system) .
  • the DL channel in a communications system may be considered where N is a number of sub-bands, N T is a number of transmitting antennas, and N R is a number of receiving antennas.
  • Calculating the DL channel may include vectorizing the channel for each receiving antenna, where
  • a precoder it is desirable for a precoder to be the singular-value decomposition (SVD) of the corresponding channel in order to have good communications performance. That is, it is desirable for a DL precoder to be the SVD of the DL channel, and it is desirable for an UL precoder to be the SVD of the UL channel.
  • SVD singular-value decomposition
  • UL and DL channels may sometimes have poor reciprocity, and thus generating SD and FD bases for the DL channel based on the estimated UL channel may result in poor performance of a DL precoder based on those SD and FD bases.
  • Techniques for updating those DL precoders may improve the performance of the DL precoders and the performance of the wireless communications system.
  • aspects of the present disclosure provide techniques and apparatus for updating precoders in frequency division duplex (FDD) communications systems.
  • FDD frequency division duplex
  • a BS may update a precoder (e.g., a DL precoder generated based on an UL channel) based on explicit feedback (e.g., measurements of the channel) regarding a channel (e.g., the DL channel) received from a UE.
  • the UE may measure a DL channel from the BS and transmit the measurements to the BS.
  • a BS may trigger a UE to provide explicit channel feedback semi-persistently, aperiodically, or periodically.
  • the precoder can be initialized based on the estimated UL channel where U UL is the SVD of the UL channel.
  • FIG. 4 is an exemplary transmission timeline 400 of a UE providing periodic channel feedback for updating a DL precoder, in accordance with aspects of the present disclosure.
  • a gNB e.g., a BS such as BS 110a, shown in FIGs. 1 &2
  • a UE e.g., UE 120a, shown in FIGs. 1 &2
  • explicit channel feedback e.g., measurements of the DL channel
  • the BS initializes the precoder based on the estimated UL channel U UL .
  • the BS transmits, using the precoder one or more reference signals (e.g., channel state information reference signals (CSI-RS) ) , which the UE measures.
  • the UE transmits explicit feedback (e.g., measurements that the UE made during the period 404) regarding the DL channel to the BS.
  • the BS updates the precoder to based on the explicit feedback received at 406.
  • the BS transmits, using the precoder one or more other reference signals, which the UE measures.
  • the UE transmits explicit feedback (e.g., measurements that the UE made during the period 420) regarding the DL channel to the BS.
  • the UE measures the DL channel based on reference signals that the BS transmitted during the previous set of slots using the precoder updated by the BS in the previous set of slots. Also during each of the first through p sets of T slots 420 to 430, the BS updates the precoder according to the measurements made by the UE during the previous set of slots.
  • a BS may configure two groups of CSI-RS ports via signaling to a UE.
  • the BS may also initialize a precoder where is a matrix corresponding to a first group of r ports of the CSI-RS ports, and is a matrix corresponding to a second group of m ports of the CSI-RS ports.
  • the BS may transmit CSI-RS corresponding to the configured CSI-RS ports.
  • the BS may transmit the CSI-RS using a precoder where is an estimated subspace of the channel (e.g., a precoder determined based on the estimated channel) and corresponds to the above-described first group of r ports.
  • r is the maximum possible rank of a transmission from the BS to the UE.
  • r can be set equal to a number of UE receiving antennas (e.g., antennas 252, shown in FIG. 2) .
  • a BS e.g., gNB, such as BS 110a
  • transmits reference signals e.g., CSI-RS
  • the BS gradually updates to the subspace of the channel by changing based on measurements received from the UE.
  • FIG. 5 is an exemplary transmission timeline 500 of a UE providing periodic channel feedback for updating a DL precoder, in accordance with aspects of the present disclosure.
  • a gNB e.g., a BS such as BS 110a, shown in FIGs. 1 &2
  • a UE e.g., UE 120a, shown in FIGs. 1 &2
  • explicit channel feedback e.g., measurements of the DL channel
  • the BS initializes the precoder based on the estimated UL channel U UL .
  • the BS transmits, using the precoder W, one or more reference signals (e.g., channel state information reference signals (CSI-RS) ) , which the UE measures.
  • the UE transmits explicit feedback (e.g., measurements that the UE made during the period 504) regarding the DL channel to the BS.
  • the BS updates the precoder to based on the explicit feedback received at 506.
  • the BS transmits, using the precoder one or more other reference signals, which the UE measures.
  • the UE transmits explicit feedback (e.g., measurements that the UE made during the period 520) regarding the DL channel to the BS.
  • the UE measures the DL channel based on reference signals that the BS transmitted during the previous set of slots using the precoder updated by the BS in the previous set of slots. Also during each of the first through p sets of T slots 520 to 530, the BS updates the precoder according to the measurements made by the UE during the previous set of slots.
  • a UE may report actual propagation channel measurements indicated by a precoding matrix indicator (PMI) of a transmission from a BS (e.g., a gNB) back to the BS when the BS triggers the UE to report the measurements for a precoder update.
  • PMI precoding matrix indicator
  • the UE separates the measurements of the channel into two groups.
  • In the first group are measurements that correspond to precoder for the r ports.
  • In the second group are measurements that correspond to precoder for up to m ports.
  • the UE sorts the measurements in the second group according to the received power of the reference signals corresponding to those ports. The UE then picks n out of the m measurements corresponding to the n reference signals with the highest received power.
  • the UE may feedback quantizations of the measurements in the first group and the picked n measurements in the second group.
  • the quantization e.g., number of bits used to encode
  • the quantization for the measurements in the first group and the quantization for the measurements in the second group may be different.
  • the UE may use four bits for each measurement in the first group to report up to 16 different values, and the UE may use two bits for each measurement in the second group to report up to 4 different values.
  • the UE may report the measurements for just a single antenna, select a out of the number of receiving antennas (N R ) and report measurements for those a antennas, or feedback the measurements for all N R antennas.
  • an example procedure for updating a precoder may be as follows.
  • the example procedure begins with a BS estimating (e.g., based on sounding reference signals (SRS) from a UE) an UL channel in order to calculate the reciprocal DL channel and generate an initial joint FD/SD basis based on the reciprocal DL channel.
  • a BS may configure the 1st ⁇ 4th CSI-RS ports with and the 5th ⁇ 16th ports with
  • the UE measures the precoded channel (e.g., measures the CSI-RS transmitted by the BS) .
  • the UE selects the n measurements in the second group having the highest received power.
  • the UE reports the quantized r measurements for the CSI-RS ports configured with the selected n measurements, and identifiers associated with the selected n measurements.
  • the BS updates according to the reported measurements.
  • a BS may configure two groups of CSI-RS ports via signaling and transmit CSI-RS using a precoder corresponds to the first group of r ports, and corresponds to the second group of m ports.
  • the BS transmit CSI-RS over a period (e.g., T slots) .
  • the BS may keep precoder unchanged until the precoder update is triggered, and the BS may change the precoder during the period (e.g., during each of the T slots) such that is different for each CSI-RS that the BS transmits.
  • FIG. 6 is an exemplary transmission timeline 600 of a BS transmitting CSI-RS when is different for each CSI-RS, in accordance with aspects of the present disclosure.
  • a gNB e.g., a BS such as BS 110a, shown in FIGs. 1 &2
  • a UE e.g., UE 120a, shown in FIGs. 1 &2
  • the BS transmits a first CSI-RS using a precoder
  • the precoder W may be based on the estimated UL channel U UL , as previously described.
  • the BS transmits a second CSI-RS using a precoder
  • the BS continues transmitting CSI-RS, each with a different until the BS triggers a precoder update (e.g. after T slots) .
  • the UE separates the measurements of the channel into two groups.
  • In the first group are measurements that correspond to precoder for the r ports at the time the precoder update is triggered.
  • In the second group are measurements that correspond to the various precoders for up to m ports for the entire period from a most recent period that the BS triggered a precoder update to the current time (e.g., the time that the BS triggered a current precoder update) .
  • the UE sorts the measurements in the second group according to the received power of the reference signals corresponding to those ports.
  • an example procedure for updating a precoder may be as follows.
  • the example procedure begins with a BS estimating (e.g., based on sounding reference signals (SRS) from a UE) an UL channel in order to calculate the reciprocal DL channel and generate an initial joint FD/SD basis based on the reciprocal DL channel.
  • SRS sounding reference signals
  • FIG. 7 is a flow diagram illustrating example operations 700 for wireless communication, in accordance with certain aspects of the present disclosure.
  • the operations 700 may be performed, for example, by a UE (e.g., the UE 120a in the wireless communication network 100) .
  • the operations 700 may be implemented as software components that are executed and run on one or more processors (e.g., controller/processor 280 of FIG. 2) .
  • the transmission and reception of signals by the UE in operations 700 may be enabled, for example, by one or more antennas (e.g., antennas 252 of FIG. 2) .
  • the transmission and/or reception of signals by the UE may be implemented via a bus interface of one or more processors (e.g., controller/processor 280) obtaining and/or outputting signals.
  • Operations 700 may continue, at block 704, by determining measurements of a propagation channel based on the first signal.
  • the UE determines measurements of the propagation channel (i.e., the propagation channel from the BS to the UE) based on (e.g., measurements of) the first signal of block 702.
  • Means for performing the functionalities of block 704 can, but not necessarily, include, for example, antennas 252, demodulator (s) 254, MIMO detector 256, receive processor 258, controller/processor 280, and/or the like with reference to FIG. 2 and/or transceiver 908, antenna 910, and/or processing system 902 with reference to FIG. 9.
  • operations 700 may continue by transmitting the measurements to the BS.
  • the UE may transmit the measurements of the propagation channel of block 704 (which are based on the first signal of block 702) to the BS.
  • the UE may transmit any combination of the first group of measurements, the second group of measurements, quantized measurements of the first group, quantized measurements of the second group, and/or the n measurements from the second group corresponding to signals having the highest received power.
  • Means for performing the functionalities of block 706 can, but not necessarily, include, for example, antenna (s) 252, modulator (s) 254, TX MIMO processor 266, transmit processor 264, controller/processor 280, and/or the like with reference to FIG. 2 and/or transceiver 908, antenna 910, and/or processing system 902 with reference to FIG. 9.
  • FIG. 8 is a flow diagram illustrating example operations 800 for wireless communication, in accordance with certain aspects of the present disclosure.
  • the operations 800 may be performed, for example, by a BS (e.g., the BS 110a in the wireless communication network 100) .
  • the operations 800 may be complimentary to the operations 700 performed by the UE.
  • the operations 800 may be implemented as software components that are executed and run on one or more processors (e.g., controller/processor 240 of FIG. 2) .
  • the transmission and reception of signals by the BS in operations 800 may be enabled, for example, by one or more antennas (e.g., antennas 234 of FIG. 2) .
  • the transmission and/or reception of signals by the BS may be implemented via a bus interface of one or more processors (e.g., controller/processor 240) obtaining and/or outputting signals.
  • the operations 800 may begin, at block 802, by transmitting, using a first precoder, a first signal to a user equipment (UE) .
  • a BS e.g., BS 110a, shown in FIGs. 1-2
  • a signal e.g., a CSI-RS or other reference signal, as described above with reference to FIGs. 4-6
  • the BS may determine the first precoder (e.g., the portion when ) based on an estimate of the uplink channel from the UE.
  • the first precoder may include first vectors corresponding to r CSI-RS ports and second vectors corresponding to m CSI-RS ports.
  • the BS may determine or update the second vectors based on random sequences, as described above.
  • Means for performing the functionalities of block 802 can, but not necessarily, include, for example, antennas 234, modulator (s) 232, TX MIMO processor 230, transmit processor 220, controller/processor 240, and/or the like with reference to FIG. 2 and/or transceiver 1008, antenna 1010, and/or processing system 1002 with reference to FIG. 10.
  • Operations 800 may continue, at block 804, by receiving, from the UE, measurements of a propagation channel determined by the UE based on the first signal.
  • the BS receives measurements of the propagation channel (i.e., the propagation channel from the BS to the UE) determined by the UE based on (e.g., measurements of) the first signal of block 802.
  • the BS may then receive from the UE any combination of the first group of measurements, the second group of measurements, quantized measurements of the first group, quantized measurements of the second group, and/or the n measurements from the second group corresponding to signals having the highest received power.
  • Means for performing the functionalities of block 804 can, but not necessarily, include, for example, antennas 234, demodulator (s) 232, MIMO detector 236, receive processor 238, controller/processor 240, and/or the like with reference to FIG. 2 and/or transceiver 1008, antenna 1010, and/or processing system 1002 with reference to FIG. 10.
  • the operations 800 may continue by determining a second precoder based on the first precoder and the measurements.
  • the BS may determine a second precoder (e.g., or ) based on the first precoder and the measurements.
  • Means for performing the functionalities of block 806 can, but not necessarily, include, for example, antennas 234, modulator (s) 232, TX MIMO processor 230, transmit processor 220, controller/processor 240, and/or the like with reference to FIG. 2 and/or transceiver 1008, antenna 1010, and/or processing system 1002 with reference to FIG. 10.
  • FIG. 9 illustrates a communications device 900 that may include various components (e.g., corresponding to means-plus-function components) configured to perform operations for the techniques disclosed herein, such as the operations illustrated in FIG. 7.
  • communication device 900 may be a UE 120, such as shown in FIG. 1 or FIG. 2.
  • the communications device 900 includes a processing system 902 and circuitry 924, 926, and 928 coupled to a transceiver 908 (e.g., a transmitter and/or a receiver which may include, for example, modulator (s) /demodulator (s) 254, TX MIMO processor 266, transmit processor 264, MIMO detector 256, receive processor 258, and/or processor 280 of FIG. 2) .
  • a transceiver 908 e.g., a transmitter and/or a receiver which may include, for example, modulator (s) /demodulator (s) 254, TX MIMO processor 266, transmit processor 264, MIMO detector 256, receive processor 258,
  • the transceiver 908 is configured to transmit and receive signals for the communications device 900 via an antenna 910 (e.g., antenna 910 is an example of antenna (s) 252 of FIG. 2) , such as the various signals as described herein.
  • the processing system 902 may be configured to perform processing functions for the communications device 900, including processing signals received and/or to be transmitted by the communications device 900.
  • the processing system 902 includes a processor 904 (e.g., processor 904 is an example of one of the processors 258, 264, 266, and 280 of FIG. 2) coupled to a computer-readable medium/memory 912 (e.g., medium/memory 912 is an example of memory 282 of FIG. 2) via a bus 906.
  • the computer-readable medium/memory 912 is configured to store instructions (e.g., computer-executable code) that when executed by the processing system 902, cause the processing system 902 to perform the operations illustrated in FIG. 7, or other operations for performing the various techniques discussed herein for updating precoders in FDD communications systems.
  • computer-readable medium/memory 912 stores code 914 for receiving a first signal, wherein the first signal is transmitted by a base station (BS) using a first precoder; code 916 for determining first measurements of a propagation channel based on the first signal; and code 918 for transmitting the first measurements to the BS.
  • the processing system 902 has circuitry configured to implement the code stored in the computer-readable medium/memory 912.
  • the processor 904 includes circuitry (e.g., an example of means for) 924 for receiving a first signal, wherein the first signal is transmitted by a base station (BS) using a first precoder; circuitry (e.g., an example of means for) 926 for determining first measurements of a propagation channel based on the first signal; and circuitry 928 (e.g., an example of means for) for transmitting the first measurements to the BS.
  • Circuitry 924, 926, and/or 928 could be specially designed circuitry for performing the indicated functions or could be general purpose circuitry configured or programmed to perform these functions.
  • FIG. 10 illustrates a communications device 1000 that may include various components (e.g., corresponding to means-plus-function components) configured to perform operations for the techniques disclosed herein, such as the operations illustrated in FIG. 8.
  • communication device 1000 may be a BS 110, such as shown in FIG. 1 or FIG. 2.
  • the communications device 1000 includes a processing system 1002 and circuitry 1024, 1026, and 1028 coupled to a transceiver 1008 (e.g., a transmitter and/or a receiver which may include, for example, modulator (s) /demodulator (s) 232, TX MIMO processor 230, transmit processor 220, MIMO detector 236, receive processor 238, and/or processor 240 of FIG. 2) .
  • a transceiver 1008 e.g., a transmitter and/or a receiver which may include, for example, modulator (s) /demodulator (s) 232, TX MIMO processor 230, transmit processor 220, MIMO detector 236, receive processor 238, and/
  • the processing system 1002 includes a processor 1004 (e.g., processor 1004 is an example of one of the processors 238, 220, 230, and 240 of FIG. 2) coupled to a computer-readable medium/memory 1012 (e.g., medium/memory 1012 is an example of memory 242 of FIG. 2) via a bus 1006.
  • the computer-readable medium/memory 1012 is configured to store instructions (e.g., computer-executable code) that when executed by the processing system 1002, cause the processing system 1002 to perform the operations illustrated in FIG. 8, or other operations for performing the various techniques discussed herein for updating precoders in FDD communications systems.
  • computer-readable medium/memory 1012 stores code 1014 for transmitting, using a first precoder, a first signal to a user equipment (UE) ; code 1016 for receiving, from the UE, measurements of a propagation channel determined by the UE based on the first signal; and code 1018 for determining a second precoder based on the first precoder and the measurements.
  • the processing system 1002 has circuitry configured to implement the code stored in the computer-readable medium/memory 1012.
  • the processor 1004 includes circuitry (e.g., an example of means for) 1024 for transmitting, using a first precoder, a first signal to a user equipment (UE) ; circuitry (e.g., an example of means for) 1026 for receiving, from the UE, measurements of a propagation channel determined by the UE based on the first signal; and circuitry (e.g., an example of means for) 1028 for determining a second precoder based on the first precoder and the measurements. Circuitry 1024, 1026, and/or 1028 could be specially designed circuitry for performing the indicated functions or could be general purpose circuitry configured or programmed to perform these functions.
  • circuitry 1024, 1026, and/or 1028 could be specially designed circuitry for performing the indicated functions or could be general purpose circuitry configured or programmed to perform these functions.
  • a method of wireless communication by a base station (BS) comprising: transmitting, using a first precoder, a first signal to a user equipment (UE) ; receiving, from the UE, measurements of a propagation channel determined by the UE based on the first signal; and determining a second precoder based on the first precoder and the measurements.
  • BS base station
  • UE user equipment
  • Aspect 3 The method of one of Aspects 1-2, further comprising: determining the first precoder based on an estimate of an uplink channel from the UE.
  • Aspect 4 The method of one of Aspects 1-3, wherein: the first precoder comprises first vectors and second vectors; each of the first vectors corresponds to a first channel state information (CSI) reference signal (CSI-RS) port in a first group of CSI-RS ports; each of the second vectors comprises a random sequence and corresponds to a second CSI-RS port in a second group of CSI-RS ports; and determining the second precoder comprises updating each of the first vectors to a new first vector based on the measurements.
  • CSI channel state information
  • CSI-RS channel state information reference signal
  • Aspect 5 The method of Aspect 4, wherein determining the second precoder further comprises updating each of the second vectors based on other random sequences.
  • Aspect 6 The method of Aspect 4, wherein: the measurements comprise a first group of the measurements that each correspond to one of the first CSI-RS ports and a second group of the measurements that each correspond to one of the second CSI-RS ports; and determining the second precoder comprises updating each of the first vectors to new first vectors based on the first group of the measurements and updating the second vectors corresponding to the second CSI-RS ports corresponding to the second group of the measurements.
  • Aspect 7 The method of one of Aspects 1-6, wherein the first precoder comprises first vectors and second vectors that each comprise a random sequence, and the method further comprises: transmitting a plurality of second signals to the UE, each second signal transmitted using one of a plurality of third precoders, wherein: each third precoder comprises the first vectors and third vectors that each comprise another random sequence; the measurements of the propagation channel are determined by the UE based further on the second signals; and determining the second precoder is based further on the third precoders.
  • a method for wireless communications by a user equipment (UE) comprising: receiving a first signal, wherein the first signal is transmitted by a base station (BS) using a first precoder; determining measurements of a propagation channel based on the first signal; and transmitting the measurements to the BS.
  • UE user equipment
  • Aspect 9 The method of Aspect 8, further comprising: receiving a trigger, wherein the UE transmits the measurements in response to the trigger.
  • Aspect 10 The method of one of Aspects 8-9, further comprising: transmitting an uplink signal to the BS, wherein the BS determines the first precoder based on an estimate of an uplink channel of the uplink signal.
  • Aspect 11 The method of one of Aspects 8-10, wherein: the first precoder comprises first vectors and second vectors; each of the first vectors corresponds to a first channel state information (CSI) reference signal (CSI-RS) port in a first group of CSI-RS ports; each of the second vectors corresponds to a second CSI-RS port in a second group of CSI-RS ports; and determining the measurements comprises: determining a first group of the measurements that each correspond to one first CSI-RS port, wherein each first CSI-RS port corresponds to at least one measurement in the first group; determining a second group of the measurements that each correspond to one second CSI-RS port, wherein each second CSI-RS port corresponds to at least one measurement in the second group; selecting a subset of the second group of the measurements according to received power of the CSI-RSs of the second CSI-RS ports; and transmitting the measurements comprises transmitting the first group of the measurements and the subset of the second group of the measurements.
  • CSI channel state information
  • Aspect 12 The method of Aspect 11, wherein transmitting the first measurements comprises: quantizing the first group of the measurements according to a first quantization; and quantizing the subset of the second group of the measurements according to a second quantization different from the first quantization.
  • Aspect 13 The method of one of Aspects 8-12, wherein the first precoder comprises first vectors and second vectors, and the method further comprises: receiving a plurality of second signals from the BS, each second signal transmitted using one of a plurality of third precoders, wherein: each third precoder comprises the first vectors and third vectors; and the measurements of the propagation channel are further based on the second signals.
  • Aspect 14 The method of Aspect 13, wherein: each of the first vectors corresponds to a first channel state information (CSI) reference signal (CSI-RS) port in a first group of CSI-RS ports; each of the second vectors corresponds to a second CSI-RS port in a second group of CSI-RS ports; and determining the measurements comprises: determining a first group of the measurements that each correspond to one of the first CSI-RS ports, wherein each first CSI-RS port corresponds to at least one measurement in the first group; determining a second group of the measurements that each correspond to one of the second CSI-RS ports, wherein each second CSI-RS port corresponds to at least one measurement in the second group; selecting a subset of the second group of the measurements according to received power of CSI-RSs of the second CSI-RS ports; and transmitting the measurements comprises transmitting the first group of the measurements and the subset of the second group of the measurements.
  • CSI channel state information
  • CSI-RS channel state information reference signal
  • a base station comprising: a memory; a transceiver; and at least one processor coupled to the transceiver and the memory and configured to: transmit, via the transceiver and using a first precoder, a first signal to a user equipment (UE) ; receive, from the UE via the transceiver, measurements of a propagation channel determined by the UE based on the first signal; and determine a second precoder based on the first precoder and the measurements.
  • BS base station
  • UE user equipment
  • Aspect 16 The BS of Aspect 15, wherein the at least one processor is further configured to: transmit, via the transceiver, a trigger to cause the UE to transmit the measurements.
  • Aspect 17 The BS of Aspect 15, wherein the at least one processor is further configured to: determine the first precoder based on an estimate of an uplink channel from the UE.
  • Aspect 18 The BS of claim 15, wherein the first precoder comprises first vectors and second vectors that each comprise a random sequence, and the at least one processor is further configured to: transmit, via the transceiver, a plurality of second signals to the UE, each second signal transmitted using one of a plurality of third precoders, wherein: each third precoder comprises the first vectors and third vectors that each comprise another random sequence; and the measurements of the propagation channel are determined by the UE based further on the second signals; and determine the second precoder based further on the third precoders.
  • a user equipment comprising: a memory; a transceiver; and at least one processor coupled to the transceiver and the memory and configured to: receive, via the transceiver, a first signal, wherein the first signal is transmitted by a base station (BS) using a first precoder; determine measurements of a propagation channel based on the first signal; and transmit, via the transceiver, the measurements to the BS.
  • BS base station
  • Aspect 20 The UE of Aspect 19, wherein the at least one processor is further configured to: receive, via the transceiver, a trigger, wherein the UE transmits, via the transceiver, the measurements in response to the trigger.
  • Aspect 21 The UE of Aspect 19, wherein the at least one processor is further configured to: transmit, via the transceiver, an uplink signal to the BS before receiving, via the transceiver, the first signal, wherein the BS determines the first precoder used for the first signal based on an estimate of an uplink channel of the uplink signal.
  • Aspect 22 The UE of Aspect 19, wherein the first precoder comprises first vectors and second vectors, and the at least one processor is further configured to: receive, via the transceiver, a plurality of second signals from the BS, each second signal transmitted using one of a plurality of third precoders, wherein each third precoder comprises the first vectors and third vectors; and determine the measurements of the propagation channel based further on the second signals.
  • Aspect 23 An apparatus for wireless communications, comprising means for performing one or more of the methods of Aspects 1-14.
  • Aspect 24 An apparatus for wireless communications, comprising: a memory; and a processor coupled to the memory, the memory and the processor configured to perform the method of one or more of Aspects 1-14.
  • Aspect 25 A computer-readable medium, the medium including instructions that, when executed by a processing system, cause the processing system to perform the method of one or more of Aspects 1-14.
  • NR e.g., 5G NR
  • LTE Long Term Evolution
  • LTE-A LTE-Advanced
  • CDMA code division multiple access
  • TDMA time division multiple access
  • FDMA frequency division multiple access
  • OFDMA orthogonal frequency division multiple access
  • SC-FDMA single-carrier frequency division multiple access
  • TD-SCDMA time division synchronous code division multiple access
  • a CDMA network may implement a radio technology such as Universal Terrestrial Radio Access (UTRA) , cdma2000, etc.
  • UTRA Universal Terrestrial Radio Access
  • UTRA includes Wideband CDMA (WCDMA) and other variants of CDMA.
  • cdma2000 covers IS-2000, IS-95 and IS-856 standards.
  • a TDMA network may implement a radio technology such as Global System for Mobile Communications (GSM) .
  • GSM Global System for Mobile Communications
  • An OFDMA network may implement a radio technology such as NR (e.g. 5G RA) , Evolved UTRA (E-UTRA) , Ultra Mobile Broadband (UMB) , IEEE 802.11 (Wi-Fi) , IEEE 802.16 (WiMAX) , IEEE 802.20, Flash-OFDMA, etc.
  • NR e.g. 5G RA
  • E-UTRA Evolved UTRA
  • UMB Ultra Mobile Broadband
  • IEEE 802.11 Wi-Fi
  • IEEE 802.16 WiMAX
  • IEEE 802.20 Flash-OFDMA
  • UTRA and E-UTRA are part of Universal Mobile Telecommunication System (UMTS) .
  • LTE and LTE-A are releases of UMTS that use E-UTRA.
  • UTRA, E-UTRA, UMTS, LTE, LTE-A and GSM are described in documents from an organization named “3rd Generation Partnership Project” (3GPP) .
  • cdma2000 and UMB are described in documents from an organization named “3rd Generation Partnership Project 2” (3GPP2) .
  • NR is an emerging wireless communications technology under development.
  • the term “cell” can refer to a coverage area of a Node B (NB) and/or a NB subsystem serving this coverage area, depending on the context in which the term is used.
  • NB Node B
  • BS next generation NodeB
  • AP access point
  • DU distributed unit
  • TRP transmission reception point
  • a BS may provide communication coverage for a macro cell, a pico cell, a femto cell, and/or other types of cells.
  • a macro cell may cover a relatively large geographic area (e.g., several kilometers in radius) and may allow unrestricted access by UEs with service subscription.
  • a pico cell may cover a relatively small geographic area and may allow unrestricted access by UEs with service subscription.
  • a femto cell may cover a relatively small geographic area (e.g., a home) and may allow restricted access by UEs having an association with the femto cell (e.g., UEs in a Closed Subscriber Group (CSG) , UEs for users in the home, etc. ) .
  • a BS for a macro cell may be referred to as a macro BS.
  • a BS for a pico cell may be referred to as a pico BS.
  • a BS for a femto cell may be referred to as a femto BS or a home BS.
  • a UE may also be referred to as a mobile station, a terminal, an access terminal, a subscriber unit, a station, a Customer Premises Equipment (CPE) , a cellular phone, a smart phone, a personal digital assistant (PDA) , a wireless modem, a wireless communication device, a handheld device, a laptop computer, a cordless phone, a wireless local loop (WLL) station, a tablet computer, a camera, a gaming device, a netbook, a smartbook, an ultrabook, an appliance, a medical device or medical equipment, a biometric sensor/device, a wearable device such as a smart watch, smart clothing, smart glasses, a smart wrist band, smart jewelry (e.g., a smart ring, a smart bracelet, etc.
  • CPE Customer Premises Equipment
  • PDA personal digital assistant
  • WLL wireless local loop
  • MTC machine-type communication
  • eMTC evolved MTC
  • MTC and eMTC UEs include, for example, robots, drones, remote devices, sensors, meters, monitors, location tags, etc., that may communicate with a BS, another device (e.g., remote device) , or some other entity.
  • a wireless node may provide, for example, connectivity for or to a network (e.g., a wide area network such as Internet or a cellular network) via a wired or wireless communication link.
  • a network e.g., a wide area network such as Internet or a cellular network
  • Some UEs may be considered Internet-of-Things (IoT) devices, which may be narrowband IoT (NB-IoT) devices.
  • IoT Internet-of-Things
  • NB-IoT narrowband IoT
  • a scheduling entity (e.g., a BS) allocates resources for communication among some or all devices and equipment within its service area or cell.
  • the scheduling entity may be responsible for scheduling, assigning, reconfiguring, and releasing resources for one or more subordinate entities. That is, for scheduled communication, subordinate entities utilize resources allocated by the scheduling entity.
  • Base stations are not the only entities that may function as a scheduling entity.
  • a UE may function as a scheduling entity and may schedule resources for one or more subordinate entities (e.g., one or more other UEs) , and the other UEs may utilize the resources scheduled by the UE for wireless communication.
  • a UE may function as a scheduling entity in a peer-to-peer (P2P) network, and/or in a mesh network.
  • P2P peer-to-peer
  • UEs may communicate directly with one another in addition to communicating with a scheduling entity.
  • a phrase referring to “at least one of” a list of items refers to any combination of those items, including single members.
  • “at least one of: a, b, or c” is intended to cover a, b, c, a-b, a-c, b-c, and a-b-c, as well as any combination with multiples of the same element (e.g., a-a, a-a-a, a-a-b, a-a-c, a-b-b, a-c-c, b-b, b-b-b, b-b-c, c-c, and c-c-c or any other ordering of a, b, and c) .
  • determining encompasses a wide variety of actions. For example, “determining” may include calculating, computing, processing, deriving, investigating, looking up (e.g., looking up in a table, a database or another data structure) , ascertaining and the like. Also, “determining” may include receiving (e.g., receiving information) , accessing (e.g., accessing data in a memory) and the like. Also, “determining” may include resolving, selecting, choosing, establishing and the like.
  • the various operations of methods described above may be performed by any suitable means capable of performing the corresponding functions.
  • the means may include various hardware and/or software component (s) and/or module (s) , including, but not limited to a circuit, an application specific integrated circuit (ASIC) , or processor.
  • ASIC application specific integrated circuit
  • DSP digital signal processor
  • ASIC application specific integrated circuit
  • FPGA field programmable gate array
  • PLD programmable logic device
  • a general-purpose processor may be a microprocessor, but in the alternative, the processor may be any commercially available processor, controller, microcontroller, or state machine.
  • a processor may also be implemented as a combination of computing devices, e.g., a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration.
  • an example hardware configuration may comprise a processing system in a wireless node.
  • the processing system may be implemented with a bus architecture.
  • the bus may include any number of interconnecting buses and bridges depending on the specific application of the processing system and the overall design constraints.
  • the bus may link together various circuits including a processor, machine-readable media, and a bus interface.
  • the bus interface may be used to connect a network adapter, among other things, to the processing system via the bus.
  • the network adapter may be used to implement the signal processing functions of the PHY layer.
  • a user interface e.g., keypad, display, mouse, joystick, etc.
  • a user interface e.g., keypad, display, mouse, joystick, etc.
  • the bus may also link various other circuits such as timing sources, peripherals, voltage regulators, power management circuits, and the like, which are well known in the art, and therefore, will not be described any further.
  • the processor may be implemented with one or more general-purpose and/or special-purpose processors. Examples include microprocessors, microcontrollers, DSP processors, and other circuitry that can execute software. Those skilled in the art will recognize how best to implement the described functionality for the processing system depending on the particular application and the overall design constraints imposed on the overall system.
  • the functions may be stored or transmitted over as one or more instructions or code on a computer readable medium.
  • Software shall be construed broadly to mean instructions, data, or any combination thereof, whether referred to as software, firmware, middleware, microcode, hardware description language, or otherwise.
  • Computer-readable media include both computer storage media and communication media including any medium that facilitates transfer of a computer program from one place to another.
  • the processor may be responsible for managing the bus and general processing, including the execution of software modules stored on the machine-readable storage media.
  • a computer-readable storage medium may be coupled to a processor such that the processor can read information from, and write information to, the storage medium. In the alternative, the storage medium may be integral to the processor.
  • the machine-readable media may include a transmission line, a carrier wave modulated by data, and/or a computer readable storage medium with instructions stored thereon separate from the wireless node, all of which may be accessed by the processor through the bus interface.
  • the machine-readable media, or any portion thereof may be integrated into the processor, such as the case may be with cache and/or general register files.
  • machine-readable storage media may include, by way of example, RAM (Random Access Memory) , flash memory, ROM (Read Only Memory) , PROM (Programmable Read-Only Memory) , EPROM (Erasable Programmable Read-Only Memory) , EEPROM (Electrically Erasable Programmable Read-Only Memory) , registers, magnetic disks, optical disks, hard drives, or any other suitable storage medium, or any combination thereof.
  • RAM Random Access Memory
  • ROM Read Only Memory
  • PROM Programmable Read-Only Memory
  • EPROM Erasable Programmable Read-Only Memory
  • EEPROM Electrical Erasable Programmable Read-Only Memory
  • registers magnetic disks, optical disks, hard drives, or any other suitable storage medium, or any combination thereof.
  • the machine-readable media may be embodied in a computer-program product.
  • a software module may comprise a single instruction, or many instructions, and may be distributed over several different code segments, among different programs, and across multiple storage media.
  • the computer-readable media may comprise a number of software modules.
  • the software modules include instructions that, when executed by an apparatus such as a processor, cause the processing system to perform various functions.
  • the software modules may include a transmission module and a receiving module. Each software module may reside in a single storage device or be distributed across multiple storage devices.
  • a software module may be loaded into RAM from a hard drive when a triggering event occurs.
  • the processor may load some of the instructions into cache to increase access speed.
  • One or more cache lines may then be loaded into a general register file for execution by the processor.
  • any connection is properly termed a computer-readable medium.
  • the software is transmitted from a website, server, or other remote source using a coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL) , or wireless technologies such as infrared (IR) , radio, and microwave
  • the coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave are included in the definition of medium.
  • Disk and disc include compact disc (CD) , laser disc, optical disc, digital versatile disc (DVD) , floppy disk, and disc where disks usually reproduce data magnetically, while discs reproduce data optically with lasers.
  • modules and/or other appropriate means for performing the methods and techniques described herein can be downloaded and/or otherwise obtained by a user terminal and/or base station as applicable.
  • a user terminal and/or base station can be coupled to a server to facilitate the transfer of means for performing the methods described herein.
  • various methods described herein can be provided via storage means (e.g., RAM, ROM, a physical storage medium such as a compact disc (CD) or floppy disk, etc. ) , such that a user terminal and/or base station can obtain the various methods upon coupling or providing the storage means to the device.
  • storage means e.g., RAM, ROM, a physical storage medium such as a compact disc (CD) or floppy disk, etc.
  • CD compact disc
  • floppy disk etc.
  • any other suitable technique for providing the methods and techniques described herein to a device can be utilized.

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  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Power Engineering (AREA)
  • Mobile Radio Communication Systems (AREA)

Abstract

Certains aspects de la présente divulgation concernent des appareils et des techniques pour mettre à jour des précodeurs dans des communications en duplex à répartition en fréquence. Par exemple, un équipement utilisateur (UE) peut recevoir un premier signal, le premier signal étant transmis par une station de base (BS) à l'aide d'un premier précodeur, déterminer des premières mesures d'un canal de propagation sur la base du premier signal, et transmettre les premières mesures à la BS.
PCT/CN2020/115040 2020-09-14 2020-09-14 Mise à jour de précodeurs dans des communications duplex à répartition en fréquence WO2022052099A1 (fr)

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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2011123008A1 (fr) * 2010-04-01 2011-10-06 Telefonaktiebolaget L M Ericsson (Publ) Livres de codage de précodeur pour des canaux efficaces ayant une sélectivité de fréquence structurée
WO2018038648A1 (fr) * 2016-08-22 2018-03-01 Telefonaktiebolaget Lm Ericsson (Publ) Nœud radio et procédé associé pour déterminer des précodeurs
WO2018169375A1 (fr) * 2017-03-17 2018-09-20 엘지전자 주식회사 Procédé d'application de précodeur sur la base d'un groupage de ressources dans un système de communication sans fil et dispositif associé

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2011123008A1 (fr) * 2010-04-01 2011-10-06 Telefonaktiebolaget L M Ericsson (Publ) Livres de codage de précodeur pour des canaux efficaces ayant une sélectivité de fréquence structurée
WO2018038648A1 (fr) * 2016-08-22 2018-03-01 Telefonaktiebolaget Lm Ericsson (Publ) Nœud radio et procédé associé pour déterminer des précodeurs
WO2018169375A1 (fr) * 2017-03-17 2018-09-20 엘지전자 주식회사 Procédé d'application de précodeur sur la base d'un groupage de ressources dans un système de communication sans fil et dispositif associé

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