WO2021208069A1 - Rétroaction de csi dans des réseaux à haute fréquence de train à grande vitesse - Google Patents

Rétroaction de csi dans des réseaux à haute fréquence de train à grande vitesse Download PDF

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Publication number
WO2021208069A1
WO2021208069A1 PCT/CN2020/085318 CN2020085318W WO2021208069A1 WO 2021208069 A1 WO2021208069 A1 WO 2021208069A1 CN 2020085318 W CN2020085318 W CN 2020085318W WO 2021208069 A1 WO2021208069 A1 WO 2021208069A1
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WO
WIPO (PCT)
Prior art keywords
reference signal
signal resource
resource
trp
csi
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PCT/CN2020/085318
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English (en)
Inventor
Yu Zhang
Alexandros MANOLAKOS
Muhammad Sayed Khairy Abdelghaffar
Krishna Kiran Mukkavilli
Runxin WANG
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Qualcomm Incorporated
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Priority to PCT/CN2020/085318 priority Critical patent/WO2021208069A1/fr
Publication of WO2021208069A1 publication Critical patent/WO2021208069A1/fr

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L5/00—Arrangements affording multiple use of the transmission path
    • H04L5/003—Arrangements for allocating sub-channels of the transmission path
    • H04L5/0048—Allocation of pilot signals, i.e. of signals known to the receiver
    • H04L5/0051—Allocation of pilot signals, i.e. of signals known to the receiver of dedicated pilots, i.e. pilots destined for a single user or terminal
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • 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
    • H04L25/0226—Channel estimation using sounding signals sounding signals per se
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W24/00—Supervisory, monitoring or testing arrangements
    • H04W24/10—Scheduling measurement reports ; Arrangements for measurement reports

Definitions

  • This application relates to wireless communication systems, and more particularly to methods (and associated devices and systems) for improving channel state information feedback for communicating in a high-speed train single frequency network.
  • a wireless multiple-access communications system may include a number of base stations (BSs) , each simultaneously supporting communications for multiple communication devices, which may be otherwise known as user equipment (UE) .
  • BSs may have numerous transmission and reception points (TRPs, also known as remote radio heads (RRHs) ) connected to them (e.g., via fiber) , spaced at various points distant from the BS to expand the coverage area outside the range of the BS itself.
  • TRPs transmission and reception points
  • RRHs remote radio heads
  • Some TRPs may be located along the path of a high-speed train to enable communication between the BS and UEs located on the train during transit.
  • the TRPs may operate using a single (common) frequency when communicating with a UE, making the existence of multiple TRPs transparent to the UE.
  • the UE may receive signals from multiple TRPs at once and perform channel state estimation and provide channel state information (CSI) reports based on reference signals from multiple TRPs, to determine-among other things-parameters to feed back to the BS to aid with beamforming.
  • CSI channel state information
  • Semi-open-loop CSI reporting (where the UE measures CQI assuming randomly cycling over a small set of precoding candidates) may be better suited to a rapidly-moving UE served by a BS equipped with large number of antennas. But when determining the CSI, the UE may consider the channel formed by transmissions from multiple TRPs (and, thus, represents a composite of paths/channels taken from the different TRPs) . Beamforming parameters based on the composite channel may result in suboptimal beamforming for one or more of the TRPs, however, since the individual channels from each TRP are not considered. Thus, there is a need to provide CSI reporting and beamforming capabilities suitable for a rapidly-moving UE, such as one in a moving high-speed train.
  • a method of wireless communication includes receiving, by a user equipment (UE) from a first transmission and reception point (TRP) on a single frequency network (SFN) , a first reference signal and receiving, by the UE from a second TRP on the SFN, a second reference signal.
  • the method further includes selecting, by the UE, a first reference signal resource corresponding to the first reference signal and a second reference signal resource corresponding to the second reference signal.
  • the method further includes determining, by the UE, a channel state information (CSI) report based on the first reference signal and the second reference signal, and transmitting, by the UE, the CSI report to the first TRP and the second TRP.
  • CSI channel state information
  • a method of wireless communication includes selecting, by a base station (BS) , a first reference signal for transmission by a first TRP on an SFN to a UE.
  • the method also includes selecting, by the BS, a second reference signal for transmission by a second TRP on the SFN to the UE.
  • the method further includes transmitting, by the BS, the first reference signal to the first TRP and the second reference signal to the second TRP for respective transmission to the UE, and receiving, from at least one of the first TRP or the second TRP, a CSI report from the UE based on the first and second reference signals.
  • a UE includes a transceiver configured to receive, from a first TRP on an SFN, a first reference signal, and receive, from a second TRP on the SFN, a second reference signal.
  • the UE further includes a processor configured to select a first reference signal resource corresponding to the first reference signal and a second reference signal resource corresponding to the second reference signal.
  • the processor is further configured to determine a CSI report for communicating in the SFN based on the first reference signal and the second reference signal.
  • the transceiver is further configured to transmit the CSI report to at least one of the first TRP or the second TRP.
  • a BS includes a processor configured to select a first reference signal for transmission by a first TRP on an SFN to a UE and select a second reference signal for transmission by a second TRP on the SFN to the UE.
  • the BS further includes a transceiver configured to transmit the first reference signal to the first TRP and the second reference signal to the second TRP for respective transmission to the UE.
  • the transceiver is further configured to receive, from at least one of the first TRP or the second TRP, a CSI report from the UE for communicating on the SFN based on the first and second reference signals.
  • a non-transitory computer-readable medium has program code recorded thereon.
  • the program code includes code for causing a UE to receive, from a first TRP on an SFN, a first reference signal.
  • the program code further includes code for causing the UE to receive, from a second TRP on the SFN, a second reference signal.
  • the program code further includes code for causing the UE to select a first reference signal resource corresponding to the first reference signal and a second reference signal resource corresponding to the second reference signal.
  • the program code further includes code for causing the UE to determine a CSI report for communicating in the SFN based on the first reference signal and the second reference signal.
  • the program code further includes code for causing the UE to transmit the CSI report to at least one of the first TRP or the second TRP.
  • a non-transitory computer-readable medium has program code recorded thereon.
  • the program code includes code for causing a BS to select a first reference signal for transmission by a TRP on an SFN to a UE.
  • the program code further includes code for causing the BS to select a second reference signal for transmission by a second TRP on the SFN to the UE.
  • the program code further includes code for causing the BS to transmit the first reference signal to the first TRP and the second reference signal to the second TRP for respective transmission to the UE.
  • the program code further includes code for causing the BS to receive, from at least one of the first TRP or the second TRP, a channel state information (CSI) report from the UE for communicating on the SFN based on the first and second reference signals.
  • CSI channel state information
  • a UE includes means for receiving, from a first TRP on an SFN, a first reference signal.
  • the UE further includes means for receiving, from a second TRP on the SFN, a second reference signal.
  • the UE further includes means for selecting a first reference signal resource corresponding to the first reference signal and a second reference signal resource corresponding to the second reference signal.
  • the UE further includes means for determining a CSI report for communicating in the SFN based on the first reference signal and the second reference signal.
  • the UE further includes means for transmitting the CSI report to at least one of the first TRP or the second TRP.
  • a BS includes means for selecting a first reference signal for transmission by a first TRP on an SFN to a UE.
  • the BS further includes means for selecting a second reference signal for transmission by a second TRP on the SFN to the UE.
  • the BS further includes means for transmitting the first reference signal to the first TRP and the second reference signal to the second TRP for respective transmission to the UE.
  • the BS further includes means for receiving, from at least one of the first TRP or the second TRP, a CSI report from the UE for communicating on the SFN based on the first and second reference signals.
  • FIG. 1 illustrates a wireless communication network according to some embodiments of the present disclosure.
  • FIG. 2 illustrates a high-speed train single frequency network according to embodiments of the present disclosure.
  • FIG. 3 illustrates a communication scheme in a high-speed train single frequency network according to embodiments of the present disclosure.
  • FIG. 4 illustrates a communication scheme in a high-speed train single frequency network according to embodiments of the present disclosure.
  • FIG. 5 is a block diagram of an exemplary UE according to embodiments of the present disclosure.
  • FIG. 6 is a block diagram of an exemplary BS according to embodiments of the present disclosure.
  • FIG. 7 illustrates a communication scheme in a high-speed train single frequency network according to embodiments of the present disclosure.
  • FIG. 8 illustrates a communication scheme in a high-speed train single frequency network according to embodiments of the present disclosure.
  • FIG. 9 illustrates a communication scheme in a high-speed train single frequency network according to embodiments of the present disclosure.
  • FIG. 10 illustrates a flow diagram of a wireless communication method according to embodiments of the present disclosure.
  • FIG. 11 illustrates a flow diagram of a wireless communication method according to embodiments of the present disclosure.
  • wireless communications systems also referred to as wireless communications networks.
  • the techniques and apparatus may be used for wireless communication networks such as code division multiple access (CDMA) networks, time division multiple access (TDMA) networks, frequency division multiple access (FDMA) networks, orthogonal FDMA (OFDMA) networks, single-carrier FDMA (SC-FDMA) networks, LTE networks, Global System for Mobile Communications (GSM) networks, 5 th Generation (5G) or new radio (NR) networks, as well as other communications networks.
  • CDMA code division multiple access
  • TDMA time division multiple access
  • FDMA frequency division multiple access
  • OFDMA orthogonal FDMA
  • SC-FDMA single-carrier FDMA
  • LTE Long Term Evolution
  • GSM Global System for Mobile Communications
  • 5G 5 th Generation
  • NR new radio
  • An OFDMA network may implement a radio technology such as evolved UTRA (E-UTRA) , Institute of Electrical and Electronics Engineers (IEEE) 802.11, IEEE 802.16, IEEE 802.20, flash-OFDM and the like.
  • E-UTRA evolved UTRA
  • IEEE Institute of Electrical and Electronics Engineers
  • GSM Global System for Mobile communications
  • LTE long term evolution
  • UTRA, E-UTRA, GSM, UMTS and LTE are described in documents provided from an organization named “3rd Generation Partnership Project” (3GPP)
  • cdma2000 is described in documents from an organization named “3rd Generation Partnership Project 2” (3GPP2) .
  • 3GPP 3rd Generation Partnership Project
  • 3GPP long term evolution LTE
  • LTE long term evolution
  • the 3GPP may define specifications for the next generation of mobile networks, mobile systems, and mobile devices.
  • the present disclosure is concerned with the evolution of wireless technologies from LTE, 4G, 5G, NR, and beyond with shared access to wireless spectrum between networks using a collection of new and different radio access technologies or radio air interfaces.
  • 5G networks contemplate diverse deployments, diverse spectrum, and diverse services and devices that may be implemented using an OFDM-based unified, air interface.
  • the 5G NR will be capable of scaling to provide coverage (1) to a massive Internet of things (IoTs) with an ultra-high density (e.g., ⁇ 1M nodes/km 2 ) , ultra-low complexity (e.g., ⁇ 10s of bits/sec) , ultra-low energy (e.g., ⁇ 10+years of battery life) , and deep coverage with the capability to reach challenging locations; (2) including mission-critical control with strong security to safeguard sensitive personal, financial, or classified information, ultra-high reliability (e.g., ⁇ 99.9999%reliability) , ultra-low latency (e.g., ⁇ 1 ms) , and users with wide ranges of mobility or lack thereof; and (3) with enhanced mobile broadband including extreme high capacity (e.g., ⁇ 10 Tbps/km 2 ) , extreme data rates (e.g., multi-Gbps rate, 100+ Mbps user experienced rates) , and deep awareness with advanced discovery and optimizations.
  • IoTs Internet of things
  • the 5G NR may be implemented to use optimized OFDM-based waveforms with scalable numerology and transmission time interval (TTI) ; having a common, flexible framework to efficiently multiplex services and features with a dynamic, low-latency time division duplex (TDD) /frequency division duplex (FDD) design; and with advanced wireless technologies, such as massive multiple input, multiple output (MIMO) , robust millimeter wave (mmWave) transmissions, advanced channel coding, and device-centric mobility.
  • TTI transmission time interval
  • MIMO massive multiple input, multiple output
  • mmWave millimeter wave
  • Scalability of the numerology in 5G NR with scaling of subcarrier spacing, may efficiently address operating diverse services across diverse spectrum and diverse deployments.
  • subcarrier spacing may occur with 15 kHz, for example over 5, 10, 20 MHz, and the like bandwidth (BW) .
  • BW bandwidth
  • subcarrier spacing may occur with 30 kHz over 80/100 MHz BW.
  • the subcarrier spacing may occur with 60 kHz over a 160 MHz BW.
  • subcarrier spacing may occur with 120 kHz over a 500 MHz BW.
  • the scalable numerology of the 5G NR facilitates scalable TTI for diverse latency and quality of service (QoS) requirements. For example, shorter TTI may be used for low latency and high reliability, while longer TTI may be used for higher spectral efficiency.
  • QoS quality of service
  • 5G NR also contemplates a self-contained integrated subframe design with uplink/downlink scheduling information, data, and acknowledgement in the same subframe.
  • the self-contained integrated subframe supports communications in unlicensed or contention-based shared spectrum, adaptive uplink/downlink that may be flexibly configured on a per-cell basis to dynamically switch between uplink and downlink to meet the current traffic needs.
  • an aspect disclosed herein may be implemented independently of any other aspects and that two or more of these aspects may be combined in various ways.
  • an apparatus may be implemented or a method may be practiced using any number of the aspects set forth herein.
  • such an apparatus may be implemented or such a method may be practiced using other structure, functionality, or structure and functionality in addition to or other than one or more of the aspects set forth herein.
  • a method may be implemented as part of a system, device, apparatus, and/or as instructions stored on a computer readable medium for execution on a processor or computer.
  • an aspect may comprise at least one element of a claim.
  • the present application describes mechanisms to better determine channel state information (CSI) and determine parameters for beamforming in a high-speed train (HST) single frequency network (SFN) .
  • HST SFN high-speed train
  • TRPs transmission and reception points
  • the TRPs are connected to a base station (BS) through, for example, a fiber connection, and expand the coverage area of the BS.
  • BS base station
  • Each TRP may use the same frequency and scrambling ID for downlink communication to a UE so that the UE is only aware of a single TRP or BS, regardless of how many TRPs the UE is actually communicating with.
  • a UE on the train may stop communicating with a TRP it is moving away from and/or start communicating with a TRP it is moving towards.
  • a UE may be communicating with multiple TRPs at once.
  • Each TRP may transmit a reference signal, e.g., a channel state information reference signal (CSI-RS) , which each TRP may have received from a BS.
  • CSI-RS channel state information reference signal
  • a given BS may control multiple TRPs along the path of the track.
  • the UE may use the CSI-RS to perform channel estimation and recommend parameters (e.g., for beamforming) to the BS (e.g., via one or more of the TRPs) in a channel state information (CSI) report.
  • CSI channel state information
  • a TRP and UE may separate CSI-RS transmission from the single-frequency aspects of the SFN so that UE may detect a distinct CSI-RS with a different scrambling identifier (ID) from each TRP, while still receiving downlink data communications (e.g., PDSCH) from various TRPs using the same frequency (including the distinct CSI-RSs) .
  • ID scrambling identifier
  • a UE may receive a CSI report configuration associated with multiple reference signal resources (e.g., non-zero power CSI-RS resources (NZP-CSI-RS) ) for channel measurement (also referred to as channel estimation) from two or more TRPs.
  • the UE may also receive a CSI-RS from each TRP, each CSI-RS having a different scrambling ID for example, CSI-RS 1 from a first TRP, and CSI-RS 2 from a second TRP.
  • the UE will be able to associate CSI-RS 1 and CSI-RS 2 with different TRPs for channel measurement based on the different scrambling IDs.
  • the UE will perform CSI measurement targeted toward downlink communication in a single frequency.
  • the UE may estimate a channel quality indicator (CQI) based on the combination of the respective paths of the composite channel. Further, the UE may prepare and transmit a CSI report based on the estimated CQI.
  • the report may include an indication (e.g., a CSI-RS Resource Indication (CRI) ) of which NZP-CSI-RS resource the UE selected, one from TRP 1 and one from TRP 2.
  • CCI CSI-RS Resource Indication
  • Each NZP-CSI-RS resource may be associated with a different Transmission Configuration Indicator (TCI) state, from which the UE may derive time, frequency, and/or spatial properties of the NZP CSI-RS ports from the quasi-colocated antenna ports for channel measurement.
  • TCI Transmission Configuration Indicator
  • the report may also include a precoding matrix indicator (PMI) (also referred to as i 1 herein) corresponding to a set of precoders associated with the each of selected NZP-CSI-RS resources (i.e., two PMI values, one for each set of precoders) , and a rank (i.e., number of layers) common to both NZP-CSI-RS resources.
  • PMI precoding matrix indicator
  • the CQI may be conditioned on the CRIs, PMIs, and the rank.
  • the CSI report configuration may include two NZP-CSI-RS resource sets, one for each TRP, each set including one or more NZP-CSI-RS resources.
  • the UE may select one resource from each set, use it to perform channel measurement, and indicate the selected resources (e.g., using CRIs) in the CSI report transmitted to one or both TRPs. For example, the UE may report the CSI via each TRP’s uplink channel. Alternately, the UE may report the CSI to one TRP, which may then communicate the CSI to the other TRP.
  • the selected resources e.g., using CRIs
  • the UE may be configured with a list of CSI-RS resource combinations from which to determine the CQI.
  • each resource combination may indicate a resource corresponding to the CSI-RS sent from the first TRP and a resource corresponding to the CSI-RS sent from the second TRP (as noted above, with each CSI-RS having a different ID) .
  • the list may be signaled to the UE by one of the TRPs or a BS (e.g., as part of a radio resource control (RRC) signal) at some time prior to the transmission of the CSI-RSs from the respective TRPs.
  • RRC radio resource control
  • the TRP or BS may then dynamically signal to the UE (e.g., through a downlink control information (DCI) message on the physical downlink control channel) a resource combination from the list for the next CSI-RSs from each TRP (one set or multiple into the future, for example) .
  • the UE may then condition its CSI measurements on the indicated combination. Beneficially, this reduces the searching overhead for the UE, since the UE does not have to test all the possible combinations, instead just what is dynamically signaled to the UE.
  • DCI downlink control information
  • the UE may be configured with a cycling pattern in addition to the list of CSI-RS resource combinations.
  • the pattern of resource combinations may cycle across slots, with a different CSI-RS resource combination being identified by the cycling pattern in each slot (or number of slots) starting with the indexed combination at a starting slot.
  • the UE may receive an index into the list from a BS or a TRP (e.g., through a DCI message) , thus identifying what CSI-RS resource combination to use, identified by the cycling pattern in each slot (or number of slots) starting with the indexed combination at a starting slot.
  • the starting slot may further be signaled to the UE so that the cycling pattern starts at the indicated slot.
  • the UE may select a resource combination from the list based on the index, and select subsequent combinations based on the cycling pattern.
  • a CSI-RS reuse pattern may be used, which may be beneficial along a long track where TRPs may be configured sequentially according to the cycling pattern.
  • embodiments of the present disclosure allow a UE to more accurately perform channel estimation while moving at high velocity in an HST SFN.
  • Embodiments of the present disclosure also assist a UE in selecting beamforming parameters for effective downlink communication in an HST SFN. Because the UE receives a distinct CSI-RS on each path in an SFN (e.g., a different CSI-RS scrambling ID from different TRPs communicating to the UE on different time-frequency resources) , the UE is able to estimate different beamforming parameters (i.e., the PMI for each respective TRP’s path) for each TRP. This improves the respective TRP’s beamforming on the downlink to the UE in the SFN, so that directionality to the UE while moving is improved.
  • FIG. 1 illustrates a wireless communication network 100 according to some embodiments of the present disclosure.
  • the network 100 may be a 5G network.
  • the network 100 includes a number of base stations (BSs) 105 (individually labeled as 105a, 105b, 105c, 105d, 105e, and 105f) and other network entities.
  • a BS 105 may be a station that communicates with UEs 115 and may also be referred to as an evolved node B (eNB) , a next generation eNB (gNB) , an access point, and the like.
  • eNB evolved node B
  • gNB next generation eNB
  • Each BS 105 may provide communication coverage for a particular geographic area.
  • the term “cell” may refer to this particular geographic coverage area of a BS 105 and/or a BS subsystem serving the coverage area, depending on the context in which the term is used.
  • a BS 105 may provide communication coverage for a macro cell or a small cell, such as a pico cell or a femto cell, and/or other types of cell.
  • a macro cell generally covers a relatively large geographic area (e.g., several kilometers in radius) and may allow unrestricted access by UEs with service subscriptions with the network provider.
  • a small cell such as a pico cell, would generally cover a relatively smaller geographic area and may allow unrestricted access by UEs with service subscriptions with the network provider.
  • a small cell such as a femto cell, would also generally cover a relatively small geographic area (e.g., a home) and, in addition to unrestricted access, may also provide 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, and the like) .
  • a BS for a macro cell may be referred to as a macro BS.
  • a BS for a small cell may be referred to as a small cell BS, a pico BS, a femto BS or a home BS. In the example shown in FIG.
  • the BSs 105d and 105e may be regular macro BSs, while the BSs 105a-105c may be macro BSs enabled with one of three dimension (3D) , full dimension (FD) , or massive MIMO.
  • the BSs 105a-105c may take advantage of their higher dimension MIMO capabilities to exploit 3D beamforming in both elevation and azimuth beamforming to increase coverage and capacity.
  • the BS 105f may be a small cell BS which may be a home node or portable access point.
  • a BS 105 may support one or multiple (e.g., two, three, four, and the like) cells.
  • the network 100 may support synchronous or asynchronous operation.
  • the BSs may have similar frame timing, and transmissions from different BSs may be approximately aligned in time.
  • the BSs may have different frame timing, and transmissions from different BSs may not be aligned in time.
  • the UEs 115 are dispersed throughout the wireless network 100, and each UE 115 may be stationary or mobile.
  • a UE 115 may also be referred to as a terminal, a mobile station, a subscriber unit, a station, or the like.
  • a UE 115 may be a cellular phone, a personal digital assistant (PDA) , a wireless modem, a wireless communication device, a handheld device, a tablet computer, a laptop computer, a cordless phone, a wireless local loop (WLL) station, or the like.
  • PDA personal digital assistant
  • WLL wireless local loop
  • a UE 115 may be a device that includes a Universal Integrated Circuit Card (UICC) .
  • a UE may be a device that does not include a UICC.
  • UICC Universal Integrated Circuit Card
  • the UEs 115 that do not include UICCs may also be referred to as IoT devices or internet of everything (IoE) devices.
  • the UEs 115a-115d are examples of mobile smart phone-type devices accessing network 100.
  • a UE 115 may also be a machine specifically configured for connected communication, including machine type communication (MTC) , enhanced MTC (eMTC) , narrowband IoT (NB-IoT) and the like.
  • MTC machine type communication
  • eMTC enhanced MTC
  • NB-IoT narrowband IoT
  • the UEs 115e-115k are examples of various machines configured for communication that access the network 100.
  • a UE 115 may be able to communicate with any type of the BSs, whether macro BS, small cell, or the like, as well as in some embodiments with any type of other UE 115.
  • a lightning bolt indicates wireless transmissions between a UE 115 and a serving BS 105, which is a BS designated to serve the UE 115 on the downlink and/or uplink, or desired transmission between BSs, and backhaul transmissions between BSs, or sidelink transmissions between UEs (or via UEs serving as relays to BSs) .
  • the BSs 105a-105c may serve the UEs 115a and 115b using 3D beamforming and coordinated spatial techniques, such as coordinated multipoint (CoMP) or multi-connectivity.
  • the macro BS 105d may perform backhaul communications with the BSs 105a-105c, as well as small cell, the BS 105f.
  • the macro BS 105d may also transmits multicast services which are subscribed to and received by the UEs 115c and 115d.
  • Such multicast services may include mobile television or stream video, or may include other services for providing community information, such as weather emergencies or alerts, such as Amber alerts or gray alerts.
  • the BSs 105 may also communicate with a core network.
  • the core network may provide user authentication, access authorization, tracking, Internet Protocol (IP) connectivity, and other access, routing, or mobility functions.
  • IP Internet Protocol
  • At least some of the BSs 105 (e.g., which may be an example of a gNB or an access node controller (ANC) ) may interface with the core network through backhaul links (e.g., NG-C, NG-U, etc. ) and may perform radio configuration and scheduling for communication with the UEs 115.
  • the BSs 105 may communicate, either directly or indirectly (e.g., through core network) , with each other over backhaul links (e.g., X1, X2, etc. ) , which may be wired or wireless communication links.
  • the network 100 may also support mission critical communications with ultra-reliable and redundant links for mission critical devices, such as the UE 115e, which may be a drone. Redundant communication links with the UE 115e may include links from the macro BSs 105d and 105e, as well as links from the small cell BS 105f.
  • UE 115f e.g., a thermometer
  • UE 115g e.g., smart meter
  • UE 115h e.g., wearable device
  • the network 100 may also provide additional network efficiency through dynamic, low-latency TDD/FDD communications, such as in a vehicle-to-vehicle (V2V) communication.
  • the network 100 may also further provide additional network efficiency through other device-to-device communication such as via PC5 links or other sidelinks, including according to embodiments of the present disclosure.
  • the network 100 utilizes OFDM-based waveforms for communications.
  • An OFDM-based system may partition the system BW into multiple (K) orthogonal subcarriers, which are also commonly referred to as subcarriers, tones, bins, or the like. Each subcarrier may be modulated with data.
  • the subcarrier spacing between adjacent subcarriers may be fixed, and the total number of subcarriers (K) may be dependent on the system BW.
  • the system BW may also be partitioned into subbands. In other instances, the subcarrier spacing and/or the duration of TTIs may be scalable.
  • the BSs 105 may assign or schedule transmission resources (e.g., in the form of time-frequency resource blocks (RB) ) for downlink (DL) and uplink (UL) transmissions in the network 100.
  • DL refers to the transmission direction from a BS 105 to a UE 115
  • UL refers to the transmission direction from a UE 115 to a BS 105.
  • the communication may be in the form of radio frames.
  • a radio frame may be divided into a plurality of subframes or slots, for example, about 10. Each slot may be further divided into mini-slots. In a FDD mode, simultaneous UL and DL transmissions may occur in different frequency bands.
  • each subframe includes a UL subframe in a UL frequency band and a DL subframe in a DL frequency band.
  • UL and DL transmissions occur at different time periods using the same frequency band.
  • a subset of the subframes (e.g., DL subframes) in a radio frame may be used for DL transmissions and another subset of the subframes (e.g., UL subframes) in the radio frame may be used for UL transmissions.
  • each DL or UL subframe may be further divided into several regions.
  • each DL or UL subframe may have pre-defined regions for transmissions of reference signals, control information, and data.
  • Reference signals are predetermined signals that facilitate the communications between the BSs 105 and the UEs 115.
  • a reference signal may have a particular pilot pattern or structure, where pilot tones may span across an operational BW or frequency band, each positioned at a pre-defined time and a pre-defined frequency.
  • a BS 105 may transmit cell specific reference signals (CRSs) and/or channel state information –reference signals (CSI-RSs) to enable a UE 115 to estimate a DL channel.
  • CRSs cell specific reference signals
  • CSI-RSs channel state information –reference signals
  • a UE 115 may transmit sounding reference signals (SRSs) to enable a BS 105 to estimate a UL channel.
  • Control information may include resource assignments and protocol controls.
  • Data may include protocol data and/or operational data.
  • the BSs 105 and the UEs 115 may communicate using self-contained subframes.
  • a self-contained subframe may include a portion for DL communication and a portion for UL communication.
  • a self-contained subframe may be DL-centric or UL-centric.
  • a DL-centric subframe may include a longer duration for DL communication than for UL communication.
  • a UL-centric subframe may include a longer duration for UL communication than for UL communication.
  • the network 100 may be an NR network deployed over a licensed spectrum.
  • the BSs 105 may transmit synchronization signals (e.g., including a primary synchronization signal (PSS) and a secondary synchronization signal (SSS) ) in the network 100 to facilitate synchronization.
  • the BSs 105 may broadcast system information associated with the network 100 (e.g., including a master information block (MIB) , remaining system information (RMSI) , and other system information (OSI) ) to facilitate initial network access.
  • MIB master information block
  • RMSI remaining system information
  • OSI system information
  • the BSs 105 may broadcast the PSS, the SSS, and/or the MIB in the form of synchronization signal block (SSBs) over a physical broadcast channel (PBCH) and may broadcast the RMSI and/or the OSI over a physical downlink shared channel (PDSCH) .
  • PBCH physical broadcast channel
  • PDSCH physical downlink shared channel
  • a UE 115 attempting to access the network 100 may perform an initial cell search by detecting a PSS from a BS 105.
  • the PSS may enable synchronization of period timing and may indicate a physical layer identity value.
  • the UE 115 may then receive a SSS.
  • the SSS may enable radio frame synchronization, and may provide a cell identity value, which may be combined with the physical layer identity value to identify the cell.
  • the PSS and the SSS may be located in a central portion of a carrier or any suitable frequencies within the carrier.
  • the UE 115 may receive a MIB.
  • the MIB may include system information for initial network access and scheduling information for RMSI and/or OSI.
  • the UE 115 may receive RMSI and/or OSI.
  • the RMSI and/or OSI may include radio resource control (RRC) information related to random access channel (RACH) procedures, paging, control resource set (CORESET) for physical downlink control channel (PDCCH) monitoring, physical uplink control channel (PUCCH) , physical uplink shared channel (PUSCH) , power control, and SRS.
  • RRC radio resource control
  • the UE 115 may perform a random access procedure to establish a connection with the BS 105.
  • the UE 115 may transmit a random access preamble and the BS 105 may respond with a random access response.
  • the random access response may include a detected random access preamble identifier (ID) corresponding to the random access preamble, timing advance (TA) information, a UL grant, a temporary cell-radio network temporary identifier (C-RNTI) , and/or a backoff indicator.
  • ID random access preamble identifier
  • TA timing advance
  • C-RNTI temporary cell-radio network temporary identifier
  • the UE 115 may transmit a connection request to the BS 105 and the BS 105 may respond with a connection response.
  • the connection response may indicate a contention resolution.
  • the random access preamble, the RAR, the connection request, and the connection response may be referred to as a message 1 (MSG 1) , a message 2 (MSG 2) , a message 3 (MSG 3) , and a message 4 (MSG 4) , respectively.
  • the random access procedure may be a two-step random access procedure, where the UE 115 may transmit a random access preamble and a connection request in a single transmission and the BS 105 may respond by transmitting a random access response and a connection response in a single transmission.
  • the combined random access preamble and connection request in the two-step random access procedure may be referred to as a message A (msgA) .
  • the combined random access response and connection response in the two-step random access procedure may be referred to as a message B (msgB) .
  • the UE 115 and the BS 105 can enter an operational state, where operational data may be exchanged.
  • the BS 105 may schedule the UE 115 for UL and/or DL communications.
  • the BS 105 may transmit UL and/or DL scheduling grants to the UE 115 via a PDCCH.
  • the BS 105 may transmit a DL communication signal to the UE 115 via a PDSCH according to a DL scheduling grant.
  • the UE 115 may transmit a UL communication signal to the BS 105 via a PUSCH and/or PUCCH according to a UL scheduling grant. Further, the UE 115 may transmit a UL communication signal to the BS 105 according to a configured grant scheme.
  • a configured grant transmission is an unscheduled transmission, performed on the channel without a UL grant.
  • a configured grant UL transmission may also be referred to as a grantless, grant-free, or autonomous transmission.
  • the UE 115 may transmit a UL resource via a configured grant.
  • configured-UL data may also be referred to as grantless UL data, grant-free UL data, unscheduled UL data, or autonomous UL (AUL) data.
  • a configured grant may also be referred to as a grant-free grant, unscheduled grant, or autonomous grant.
  • the resources and other parameters used by the UE for a configured grant transmission may be provided by the BS in one or more of a RRC configuration or an activation DCI, without an explicit grant for each UE transmission.
  • the UE may utilize a configured grant transmission in one or more sidelink communications with one or more other UEs (either for D2D communication or the other UE operating as an L2 or L3 relay to a BS) .
  • the coverage range of a BS 105 can be extended by connecting one or more TRPs 205 (as illustrated in FIG. 2) via, for example, a fiber connection.
  • a TRP 205 may itself be a BS 105.
  • a TRP 205 may include transmit functionality under the control of a remote BS 105, e.g. the TRP 205 may be an example of a remote radio head (RRH) .
  • RRH remote radio head
  • a BS 105 may communicate through one or more TRPs 205 with a UE 115.
  • the BS 105 may transmit data intended for the UE 115 to the TRP 205, which in turn may transit the data to the UE 115.
  • the UE 115 may transmit a signal to a BS 105 through a TRP 205 (e.g., the signal to the BS 105 may be received by a TRP 205 which may then transmit the signal to the BS 105) .
  • FIG. 2 illustrates aspects of an HST SFN 200 according to embodiments of the present disclosure.
  • BBU baseband unit
  • three TRPs 205, and one UE 115 are illustrated, but any fewer or more than three TRPs 205 and more than one UE 215 are possible according to aspects of the present disclosure.
  • BBU 202 may be an example of a BS 105 illustrated in FIG. 1, relying upon one or more of the TRPs 205 to communicate with the UE 115.
  • one or more of TRPs 205 may be examples BSs 105 in FIG. 1 (under control of one or more BBUs) .
  • TRPs 205 may be connected via links 204 (e.g., fiber) to the BBU 202 and placed at various points along the path of a railway.
  • TRP 205a is illustrated as connected to BBU 202 via link 204a
  • TRP 205b is connected to BBU 202 via link 204b
  • TRP 205c is connected to BBU 202 via link 204c.
  • the UE 115 may communicate with one or more TRPs 205.
  • UE 115 may be in range of and communicating with TRPs 205a, 205b, and 205c.
  • Each TRP 205 may transmit a CSI-RS 206 to UE 115.
  • CSI-RSs 206 may have had the same scrambling ID, making the existence of three distinct TRPs 205 invisible to UE 115, which may only see a single connection point to the network 200.
  • each CSI-RS may have a different scrambling ID and be transmitted on different time-frequency resources.
  • Communication on the downlink data channel e.g., the PDSCH
  • DMRS demodulation reference signal
  • CSI-RS 206a, 206b, and 206c may be transmitted in a non-SFN manner, but DMRS 209a, 209b, and 209c may be transmitted in an SFN manner so that UE 115 is unaware of which TRP 205 a particular downlink communication originates from.
  • FIG. 3 illustrated is part of an HST SFN 300 illustrating aspects that embodiments of the present disclosure resolve.
  • the CSI-RS 306a has the same scrambling ID (illustrated as “0” for simplicity in the figure) as CSI-RS 306b and is transmitted on the same time-frequency resource.
  • the UE 115 may use CSI-RSs 306 to perform channel estimation and assist the a BBU (e.g., BBU 202 in FIG. 2) in selectin beamforming parameters for downlink communications via TRPs 305 (e.g., on the PDSCH) using semi-open loop reporting.
  • CSI-RS 306a and 306b may include the same scrambling ID and transmitted on the same time-frequency resource, making the existence of the two discrete TRPs 305 invisible to the UE 115, which may only see a single connection point to the network 300.
  • the UE may perform channel estimation based on the composite channel formed by transmission of the two CSI-RSs 306 with the same scrambling ID and on the same time-frequency resource, and may determine parameters for use in beamforming (e.g., rank, precoder sets, and/or CSI-RS resources) based on the composite channel.
  • the UE 115 may then determine a CQI based on the selected rank, precoder sets, and/or CSI-RS resources, and create and transmit CSI report including the CQI and beamforming parameters to one or both TRPs 305.
  • the CQI may be conditioned on randomly cycling the precoders in the set across PRGs.
  • the TRPs 305 may not optimally beamform their transmissions to the UE 115.
  • UE 115 may select a single precoder set (e.g., a single i 1 ) for use by both TRP 305a and TRP 305b.
  • a single precoder set e.g., a single i 1
  • an optimal beam 310 from TRP 305a may be highly directional in a direction along the path 308a
  • an optimal beam from TRP 305b may be highly directional in a direction along the path 308b.
  • the resulting beam 310 for TRP 305b does not have high directionality along path 308b, but instead provides higher directionality along the path 305c.
  • This is suboptimal because it provides the highest gain along the directionality along a path 305c that does not directly point towards the UE 115. This approach, therefore, results in suboptimal beamforming for one or more of the TRPs 305.
  • FIG. 4 illustrates part of an HST SFN 400 according to embodiments of the present disclosure.
  • the semi-open loop CSI measurement process may be decoupled from the SFN aspects of the network, resulting in improved beamforming as described herein.
  • HST SFN 400 may be part of the HST SFN 200, and TRPs 405a and 405b may be any two of the TRPs 205 as discussed with respect to FIG. 2 (by way of example for purposes of simplicity of discussion herein) .
  • the UE 115 may receive CSI-RS 406a and 406b and use these to perform channel estimation and select parameters to recommend for beamforming at the network (e.g., rank, precoder sets, and/or CSI-RS resources) .
  • CSI-RSs 406a and 406b each have a distinct ID (e.g., a scrambling ID) from each other, making it possible for UE 115 to determine CSI based on the individual channels corresponding to CSI-RS 406a transmitted from TRP 410a and CSI-RS 406b transmitted from TRP 405b.
  • the respective channels from TRP 405a and TRP 405b are effectively visible to UE 115.
  • UE 115 may select distinct precoder sets (e.g., i 1 s) for performing CSI measurements, as described in detail in FIGs. 7-11.
  • a better path between TRP 405a and UE 115 may be the path 408a, which is in a direction covered by the directionality of the pattern 410a resulting from the precoder set determined from CSI-RS 406a.
  • a better path between TRP 405b and UE 115 may be the path 408b, which is in a direction covered by the directionality of the pattern 410b resulting from the precoder set determined from CSI-RS 406b.
  • the UE 115 Since the UE 115 is no longer limited to selecting the same precoder set for both TRPs 405, the UE chooses distinct precoder sets 410a and 410b, resulting in improved beamforming gains from each of the TRPs 405a, 405b to the UE 115.
  • the UE 115 may receive a CSI configuration associated with CSI-RS resources (e.g., NZP-CSI-RS resources) of CSI-RS 406a for TRP 405a, and a CSI configuration associated with CSI-RS resources of CSI-RS 406b for TRP 405b.
  • the CSI configuration may be received via RRC messaging, such as from one or both of the TRPs 405 or some other BS 105 (see FIG. 1) at some earlier time.
  • the UE 115 is configured with multiple different possible CSI-RS resource combinations (one set of CSI-RS resources corresponding to each of the TRPs 405) .
  • UE 115 may perform channel measurement targeted toward downlink communication in a single frequency.
  • the UE 115 may prepare and transmit a CSI report.
  • the report may include two CRIs indicating which CSI-RSs UE 115 selected (one corresponding to TRP 405a and one corresponding to TRP 405b) .
  • the report may also include two PMIs (e.g., i 1 s) corresponding to respective precoder sets, a rank common to both CSI-RS resources, and/or a coupling factor across TRP 405a and TRP 405b.
  • the CQI may be conditioned on the CRIs, i 1 s, the rank, and/or a coupling factor, and be included in the report.
  • the CSI report configuration may include two NZP-CSI-RS resource sets, each set including one or more NZP-CSI-RS resources.
  • Each resource set may be associated with one or more TRPs, such as TRPs 405a and 405b in FIG. 4.
  • TRPs 405a and 405b in FIG. 4.
  • a given TRP 405 may transmit multiple CSI-RS, and the UE 115 may select one CSI-RS from among these for the resource.
  • the UE 115 may select a CSI-RS resource from each set, use it to perform channel measurement to detect the respective CSI-RS 406a, 406b from TRPs 405a, 405b (respectively) , and indicate the selected resources (e.g., using CRIs) in the CSI report transmitted to one or both TRPs 405. In other words, the UE 115 may signal back to the TRP (s) 405 the selected resource for each CSI-RS separately. Each of the selected resources may also be associated with a different TCI state.
  • the UE 115 may be configured with a list of CSI-RS resource combinations.
  • each resource combination may indicate a resource corresponding to TRP 405a and a resource corresponding to TRP 405b.
  • the list may be signaled to UE 115 by one of the TRPs 405 or a different BS 105 (e.g., as part of a radio resource control (RRC) signal) .
  • the TRP 405 or BS 105 may then dynamically signal to the UE 115 (e.g., through a downlink control information (DCI) message) a resource combination from the list.
  • DCI downlink control information
  • the UE may then condition its CSI measurements (e.g., of CSI-RS 406a from TRP 405a and CSI-RS 406b from TRP 405b) on the indicated combination.
  • DCI downlink control information
  • the UE 115 may be configured with a cycling pattern in addition to the list of CSI-RS resource combinations. The UE 115 may then dynamically receive an index into the list from a BS 105 or a TRP 405 (e.g., through a DCI message) . The UE 115 may select a resource combination from the list based on the index, and select subsequent combinations for later CSI-RS from TRPs based on the cycling pattern. Further, the UE 115 may also dynamically receive a slot offset and an index into the list of combinations from a BS 105 or a TRP 405 (e.g., through a DCI message) .
  • the UE 115 may select a resource combination from the list based on the index, and start using the combination after the number of slots indicated by the slot offset.
  • the cycling pattern may also include a periodicity of slots during which the given combination is used. After the number of slots indicated by the periodicity has elapsed, the UE 115 may then select the next combination based on the cycling pattern.
  • FIG. 5 is a block diagram of an exemplary UE 500 according to embodiments of the present disclosure.
  • the UE 500 may be a UE 115 as discussed above in FIGs. 1-4.
  • the UE 500 may include a processor 502, a memory 504, a channel state module 508, a transceiver 510 including a modem subsystem 512 and a radio frequency (RF) unit 514, and one or more antennas 516.
  • RF radio frequency
  • the processor 502 may include a central processing unit (CPU) , a digital signal processor (DSP) , an application specific integrated circuit (ASIC) , a controller, a field programmable gate array (FPGA) device, another hardware device, a firmware device, or any combination thereof configured to perform the operations described herein.
  • the processor 502 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.
  • the memory 504 may include a cache memory (e.g., a cache memory of the processor 502) , random access memory (RAM) , magnetoresistive RAM (MRAM) , read-only memory (ROM) , programmable read-only memory (PROM) , erasable programmable read only memory (EPROM) , electrically erasable programmable read only memory (EEPROM) , flash memory, solid state memory device, hard disk drives, other forms of volatile and non-volatile memory, or a combination of different types of memory.
  • the memory 504 includes a non-transitory computer-readable medium.
  • the memory 504 may store, or have recorded thereon, instructions 506.
  • the instructions 506 may include instructions that, when executed by the processor 502, cause the processor 502 to perform the operations described herein with reference to the UEs 115 in connection with embodiments of the present disclosure, for example, aspects of FIGs. 1-4 and 7-10. Instructions 506 may also be referred to as program code.
  • the program code may be for causing a wireless communication device (or specific component (s) of the wireless communication device) to perform these operations, for example by causing one or more processors (such as processor 502) to control or command the wireless communication device (or specific component (s) of the wireless communication device) to do so.
  • the terms “instructions” and “code” should be interpreted broadly to include any type of computer-readable statement (s) .
  • instructions and code may refer to one or more programs, routines, sub-routines, functions, procedures, etc. “Instructions” and “code” may include a single computer-readable statement or many computer-readable statements.
  • the channel state module 508 may be implemented via hardware, software, or combinations thereof.
  • channel state module 508 may be implemented as a processor, circuit, and/or instructions 506 stored in the memory 504 and executed by the processor 502.
  • the channel state module 508 can be integrated within the modem subsystem 512.
  • the channel state module 508 can be implemented by a combination of software components (e.g., executed by a DSP or a general processor) and hardware components (e.g., logic gates and circuitry) within the modem subsystem 512.
  • the channel state module 508 may be used for various aspects of the present disclosure, for example, aspects of FIGs. 1-4 and 7-11.
  • the channel state module 508 is configured to communicate with other components of the UE 500 to measure CSI and assist in determining CSIs, including different beamforming parameters for different paths from different TRPs to the UE 500, in an HST SFN as described in the present disclosure.
  • the channel state module 508 may be configured to receive a CSI configuration associated with CSI-RS resources (e.g., NZP-CSI-RS resources) of a first CSI-RS from a first TRP 206 and a CSI configuration associated with CSI-RS resources of a second CSI-RS from a second TRP 206.
  • CSI-RS resources e.g., NZP-CSI-RS resources
  • the CSI configuration may be determined and originate at a BS 105.
  • the channel state module 508 may also receive a first CSI-RS from the first TRP 206 and a second CSI-RS from the second TRP 206.
  • the channel state module 508 may perform channel measurement targeted toward downlink communication in a single (shared) frequency after receiving the report configuration and CSI-RS.
  • the channel state module 508 may also be configured to determine a CQI for SFN transmission and include the CQI in a CSI report.
  • the report may include two CRIs indicating which CSI-RS resources the channel state module 508 selected (one from the first TRP 206 and one from the second TRP 206) .
  • the report may also include two PMIs (e.g., i 1 s) corresponding to a first precoder set for the first TRP 206 and a second precoder set for the second TRP 206, and a rank common to both CSI-RS resources.
  • the CQI may be conditioned on the CRIs, i 1 s, the rank, and/or a coupling factor, and included in the report.
  • the channel state module 508 may be configured to transmit the report to the first and/or second TRP 206.
  • the CSI report configuration may include two NZP-CSI-RS resource sets, one for each of the two TRPs 206, each set including one or more NZP-CSI-RS resources.
  • the channel state module 508 may be configured to select one resource from each set, use it to perform channel measurement, and indicate the selected resources (e.g., using CRIs) in the CSI report transmitted to one or both TRPs 206.
  • the channel state module 508 may be configured with a list of CSI-RS resource combinations.
  • each resource combination may indicate a resource corresponding to the first TRP 206 and a resource corresponding to the second TRP 206.
  • the list may be signaled to the channel state module 508 by one of the TRPs 206 and originate at the BS 105 (e.g., as part of a radio resource control (RRC) signal) .
  • the TRP 206 may then dynamically signal to the channel state module 508 (e.g., through a downlink control information (DCI) message originating at the BS 105) a resource combination from the list.
  • DCI downlink control information
  • the UE 500 may then condition its CSI measurements on the indicated combination until another combination is signaled to the UE 500.
  • the channel state module 508 may be configured with a cycling pattern in addition to the list of CSI-RS resource combinations. The channel state module 508 may then dynamically receive an index into the list from a TRP 206 (e.g., through a DCI message originating at the BS 105) . The channel state module 508 may also be configured to select a resource combination from the list based on the index, and select subsequent combinations based on the cycling pattern. The channel state module 508 may further be configured with a slot offset and an index into the list of combinations from a TRP 206 (e.g., through a DCI message originating at the BS 105) .
  • the channel state module 508 may select a resource combination from the list based on the index and start using the combination after the number of slots indicated by the slot offset. After a number of slots indicated by the cycling pattern (e.g., also referred to herein as a periodicity) , the channel state module 508 may then select the next combination based on the cycling pattern.
  • a number of slots indicated by the cycling pattern e.g., also referred to herein as a periodicity
  • the transceiver 510 may include the modem subsystem 512 and the RF unit 514.
  • the transceiver 510 can be configured to communicate bi-directionally with other devices, such as the BSs 105.
  • the modem subsystem 512 may be configured to modulate and/or encode the data from the memory 504, and/or the channel state module 508 according to a modulation and coding scheme (MCS) (e.g., a low-density parity check (LDPC) coding scheme, a turbo coding scheme, a convolutional coding scheme, a digital beamforming scheme, etc. ) .
  • MCS modulation and coding scheme
  • LDPC low-density parity check
  • the RF unit 514 may be configured to process (e.g., perform analog to digital conversion or digital to analog conversion, etc.
  • modulated/encoded data e.g., UL data bursts, RRC messages, configured grant transmissions, ACK/NACKs for DL data bursts
  • modulated/encoded data e.g., UL data bursts, RRC messages, configured grant transmissions, ACK/NACKs for DL data bursts
  • the RF unit 514 may be further configured to perform analog beamforming in conjunction with the digital beamforming. Although shown as integrated together in transceiver 510, the modem subsystem 512 and the RF unit 514 may be separate devices that are coupled together at the UE 500 to enable the UE 500 to communicate with other devices.
  • the RF unit 514 may provide the modulated and/or processed data (e.g., data packets or, more generally, data messages that may contain one or more data packets and other information) to the antennas 516 for transmission to one or more other devices.
  • the antennas 516 may further receive data messages transmitted from other devices.
  • the antennas 516 may provide the received data messages for processing and/or demodulation at the transceiver 510.
  • the transceiver 510 may provide the demodulated and decoded data (e.g., system information message (s) , RACH message (s) (e.g., DL/UL scheduling grants, DL data bursts, RRC messages, ACK/NACK requests, reference signals such as CSI-RS, etc. ) to the channel state module 508 for processing.
  • the antennas 516 may include multiple antennas of similar or different designs in order to sustain multiple transmission links.
  • the RF unit 514 may configure the antennas 516.
  • the UE 500 can include multiple transceivers 510 implementing different RATs (e.g., NR and LTE) .
  • the UE 500 can include a single transceiver 510 implementing multiple RATs (e.g., NR and LTE) .
  • the transceiver 510 can include various components, where different combinations of components can implement different RATs.
  • FIG. 6 is a block diagram of an exemplary BS 600 according to embodiments of the present disclosure.
  • the BS 600 may be a BS 105 as discussed above in FIGs. 1-5.
  • the BS 600 may include a processor 602, a memory 604, a channel state module 608, a transceiver 610 including a modem subsystem 612 and a RF unit 614, and one or more antennas 616. These elements may be in direct or indirect communication with each other, for example via one or more buses.
  • the processor 602 may have various features as a specific-type processor. For example, these may include a CPU, a DSP, an ASIC, a controller, a FPGA device, another hardware device, a firmware device, or any combination thereof configured to perform the operations described herein.
  • the processor 602 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.
  • the memory 604 may include a cache memory (e.g., a cache memory of the processor 602) , RAM, MRAM, ROM, PROM, EPROM, EEPROM, flash memory, a solid state memory device, one or more hard disk drives, memristor-based arrays, other forms of volatile and non-volatile memory, or a combination of different types of memory.
  • the memory 604 may include a non-transitory computer-readable medium.
  • the memory 604 may store instructions 606.
  • the instructions 606 may include instructions that, when executed by the processor 602, cause the processor 602 to perform operations described herein, for example, aspects of FIGs. 1-4 and 7-11. Instructions 606 may also be referred to as code, which may be interpreted broadly to include any type of computer-readable statement (s) as discussed above with respect to FIG. 5.
  • the channel state module 608 may be implemented via hardware, software, or combinations thereof.
  • the channel state module 608 may be implemented as a processor, circuit, and/or instructions 606 stored in the memory 604 and executed by the processor 602.
  • the channel state module 608 can be integrated within the modem subsystem 612.
  • the channel state module 608 can be implemented by a combination of software components (e.g., executed by a DSP or a general processor) and hardware components (e.g., logic gates and circuitry) within the modem subsystem 612.
  • the channel state module 608 may be used for various aspects of the present disclosure, for example, aspects of FIGs. 1-4 and 7-11.
  • the channel state module 608 may be configured to communicate with other components of the BS 600 to help determine beamforming parameters for downlink transmissions between multiple TRPs 206 and a UE 115.
  • the channel state module 608 may be configured to select a first reference signal (e.g., and NZP-CSI-RS) for a first TRP 206 and a second reference signal for a second TRP 206 to transmit to the UE 115 in an HST SFN.
  • Each reference signal may have a unique scrambling ID.
  • the channel state module 608 may also be configured to create a CSI configuration (or process it as received from some other part of the core network) and transmit the CSI configuration through one or more TRPs 206 to the UE 115.
  • the CSI configuration may include a plurality of resource sets corresponding to the first and second reference signals, which the UE 115 may use when selecting precoder sets for communication between the UE 115 and each TRP 206.
  • the channel state module 608 may also be configured to receive, via the antennas 616 and transceiver 610 from the UE 115 through one or both of the TRPs 206 a CSI report based on the reference signals and CSI configuration.
  • the report may include a CRI corresponding to each reference signal, indicating which reference signal resources were selected by the UE 115 from each reference signal, and a PMI (e.g., an i 1 ) for each TRP indicating which precoders the UE 115 selected for each TRP (corresponding to each unique CSI-RS) .
  • Each of the selected reference signal resources may be associated with a different TCI state.
  • the report may also include a rank common to both reference signal resources.
  • the report may also include a CQI for SFN transmission from the TRPs 206 to the UE 115, based on the CRIs, i 1 s, and the rank.
  • the CSI report configuration may include two NZP-CSI-RS resource sets, one for each of the two TRPs 206, each set including one or more NZP-CSI-RS resources for the UE 115 to select from and use to perform channel measurement.
  • the channel state module 608 may receive CRIs in the CSI report which may indicate the selected NZP-CSI-RS resources.
  • the channel state module 608 may be configured to determine a list of CSI-RS resource combinations for the UE 115 to select from. For example, each resource combination may indicate a CSI-RS resource corresponding to the first TRP 206 and a CSI-RS resource corresponding to the second TRP 206.
  • the channel state module 608 may signal the list to the UE 115 through one or both TRPs 206 (e.g., as part of a radio resource control (RRC) signal) .
  • RRC radio resource control
  • the channel state module 608 may be configured to then dynamically signal to the UE (e.g., in a DCI message, through one or both TRPs 206) a resource combination from the list that the UE 115 may use next for CSI reporting.
  • the CSI report may be based on the indicated combination.
  • the channel state module 608 may be configured to determine a cycling pattern in addition to the list of CSI-RS resource combinations and transmit the cycling pattern and list to the UE 115 through one or both TRPs 206 (e.g., in an RRC signal) . The channel state module 608 may then dynamically signal an index into the list to the UE 115 (e.g., in a DCI message through one or both TRPs) for the UE 115 to use in selecting a combination to base the CSI report on. Further, the channel state module 608 may determine and transmit a slot offset for the UE 115 to use in determining when to start using the index in selecting the combination for the CSI report.
  • the channel state module 608 may determine a periodicity to include as part of the cycling pattern, which the UE 115 will use to apply the selected resource combination until a new period starts, at which time the UE 115 will transition to the next combination in the cycling pattern.
  • the transceiver 610 may include the modem subsystem 612 and the RF unit 614.
  • the transceiver 610 can be configured to communicate bi-directionally with other devices, such as the UEs 115 and/or 300 and/or another core network element.
  • the modem subsystem 612 may be configured to modulate and/or encode data according to a MCS (e.g., a LDPC coding scheme, a turbo coding scheme, a convolutional coding scheme, a digital beamforming scheme, etc. ) .
  • the RF unit 614 may be configured to process (e.g., perform analog to digital conversion or digital to analog conversion, etc.
  • modulated/encoded data e.g., RRC messages, DL data of multiple QoS flows mapped to the same DRB, etc.
  • modulated/encoded data e.g., RRC messages, DL data of multiple QoS flows mapped to the same DRB, etc.
  • the RF unit 614 may be further configured to perform analog beamforming in conjunction with the digital beamforming.
  • the modem subsystem 612 and/or the RF unit 614 may be separate devices that are coupled together at the BS 600 to enable the BS 600 to communicate with other devices.
  • the RF unit 614 may provide the modulated and/or processed data, (e.g., data packets or, more generally, data messages that may contain one or more data packets and other information) to the antennas 616 for transmission to one or more other devices.
  • the antennas 616 may further receive data messages transmitted from other devices and provide the received data messages for processing and/or demodulation at the transceiver 610.
  • the transceiver 610 may provide the demodulated and decoded data (e.g., RRC messages, UL data, CSI reports, etc. ) to the channel state module 608 for processing.
  • the antennas 616 may include multiple antennas of similar or different designs in order to sustain multiple transmission links.
  • the BS 600 can include multiple transceivers 610 implementing different RATs (e.g., NR and LTE) .
  • the BS 600 can include a single transceiver 610 implementing multiple RATs (e.g., NR and LTE) .
  • the transceiver 610 can include various components, where different combinations of components can implement different RATs.
  • FIG. 7 illustrates a communication scheme according to some embodiments of the present disclosure.
  • TRPs 704 which may be TRPs 205, 305 or 405
  • one UE 115 which may be a UE 500
  • UE 115 may be traveling on an HST along a path that takes the UE through the coverage areas of TRPs 704a, 704b, 704c, and 704d, illustrated in FIG. 7 in that order.
  • Each TRP 704 may transmit a CSI-RS with unique IDs (e.g., scrambling IDs) associated with each TRP 704 using CSI-RS resources, illustrated as respective resources 702 to be measured and reported by the UE 115.
  • unique IDs e.g., scrambling IDs
  • the UE 115 may receive a CSI report configuration, for example, in an RRC signal originating at a BS 105 (FIG. 1, which may be conveyed via a TRP 704) .
  • the report may include a list 710 of CSI-RS resource combinations that may be used to transmit CSI-RS that the UE will then use for channel measurement and determining recommended beamforming parameters for the respective TRPs, and prepare a CSI report.
  • the TRP 704 may dynamically indicate to the UE 115 which combination in the list to select, for example in a DCI originating from a BS 105, as described herein.
  • UE 115 receives from TRP 704a or TRP 704b (or both) , a dynamic signal (e.g., a DCI) indicating a combination from the list 710 of CSI-RS resources. This may be in a slot not too long before the slot in which CSI-RS are received from the TRP 704a and 704b.
  • the signal may originate at a BS 105 and may indicate the combination through an index into the list 710.
  • UE 115 When UE 115 is between TRPs 704a and 704b, it may receive a first CSI-RS from TRP 704a and a second CSI-RS from TRP 702b, each CSI-RS associated with CSI-RS resources from which the UE 115 may choose.
  • the dynamic signal indicates that the resource combination 712 should be chosen from the list 710, which indicates that UE 115 should select resource 1 702a for the first reference signal from TRP 704a and resource 2 702b for the second reference signal from the TRP 704.
  • Resource 1 702a may be associated with a different TCI state than resource 2 702b.
  • the UE 115 may measure the channel, determine beamforming parameters, and prepare a CSI report.
  • the report may include a CQI for SFN transmission between the TRPs 704a and 704b, and two PMIs (e.g., i 1 s) corresponding to a first precoder set for TRP 704a and a second precoder set for TRP 704b (the precoder sets being potentially different from each other based on the different CSI-RSs sent) , and a rank common to both CSI-RS resources.
  • the CQI may be conditioned on the CRIs, i 1 s, the rank, and/or a coupling factor, and included in the report.
  • the UE 115 may then transmit the CSI report to a BS 105 through TRP 704a and/or TRP 704b.
  • the UE 115 may then travel between TRPs 704b and 704c. As above, the UE 115 may receive a dynamic signal, this time indicating that it select the second combination (2, 3) 714 in the list 710, indicating that it use resource 2 702b and resource 3 702c to determine a CSI report for TRPs 704b and 704c, respectively, as above. After the dynamic signaling, the TRPs 704b, 704c transmit CSI-RSs associated with resources 702b and 702c respectively. Upon determining the CSI report based on the two identifiable paths, the UE 115 may transmit the CSI report to the TRPs 704b and/or 704c for delivery to a BS 105.
  • the UE 115 may then travel between TRPs 704c and 704d. As above, the UE 115 may receive a dynamic signal, this time indicating that it select the third combination (3, 1) 714 in the list 710, indicating that it use resource 3 702c and resource 1 702d to determine a CSI report for TRPs 704c and 704d, respectively, as above. After the dynamic signaling, the TRPs 704c, 704d transmit CSI-RSs associated with resources 702c and 702d respectively. Upon determining the CSI report based on the two identifiable paths, the UE 115 may transmit the CSI report to the TRPs 704c and/or 704d for delivery to a BS 105.
  • a dynamic signal this time indicating that it select the third combination (3, 1) 714 in the list 710, indicating that it use resource 3 702c and resource 1 702d to determine a CSI report for TRPs 704c and 704d, respectively, as above.
  • FIG. 8 illustrates a communication scheme 800 according to some embodiments of the present disclosure, using the same configuration as scheme 700 in FIG. 7, but with a different method of selecting CSI-RS resource combinations from the list 710.
  • UE 115 is configured with the list 710 of CSI-RS resource combinations as in FIG. 7, but in addition to the list, UE 115 receives a cycling pattern 820 from one or more TRPs 704 (e.g., as part of the CSI report configuration, or alternatively as a separate configuration message) .
  • the UE 115 may determine a CSI-RS resource combination to use for measuring the CSI-RS and preparing the CSI report as in FIG.
  • the UE 115 may determine the combination based on a slot index. Aspects including the CSI-RS transmissions and CSI report preparation remains the same as in FIG. 7, so only the way the UE selects a combination from the list 710 is described here.
  • UE 115 For the T slots 842, UE 115 will be positioned between TRP 702a and TRP 702b. The UE 115 may determine, based on the cycling pattern and the slot index (which identifies the starting resource combination to use from the list) , that for the T slots 842, the UE should select from the list 710 of resource combinations the combination 712, corresponding to CSI-RS resource 1 702a for TRP 704a, and CSI-RS resource 2 702b for TRP 704b.
  • the T parameter may be an aspect configured as part of the cycling pattern in addition to the cycling information itself. Thus, for slots 822, 824, 826, or any slot in between, the UE 115 will select the combination 712 (1, 2) from the list 710.
  • UE 115 For the T slots 844, UE 115 will be positioned between TRP 702b and TRP 702c.
  • the UE 115 may determine, based on the cycling pattern (but, in some embodiments, not the slot index which was only necessary to determine what resource combination to start with in the list 710, subsequent resource combinations being selected based on the cycling pattern) , that for the T slots 844, the UE should select from the list 710 of resource combinations the combination 714, corresponding to CSI-RS resource 2 702b for TRP 704b, and CSI-RS 3 resource 702c for TRP 704c.
  • the UE 115 will select the combination 714 (2, 3) from the list 710.
  • UE 115 For the T slots 846, UE 115 will be positioned between TRP 702c and TRP 702d.
  • the UE may determine, based on the cycling pattern (but, in some embodiments, not the slot index which was only necessary to determine what resource combination to start with in the list 710, subsequent resource combinations being selected based on the cycling pattern) , that for the T slots 846, the UE should select from the list 710 of resource combinations the combination 716, corresponding to CSI-RS resource 3 702c for TRP 704c, and CSI-RS resource 1 702d for TRP 704d.
  • the UE 115 will select the combination 716 (3, 1) from the list 710.
  • FIG. 9 illustrates a communication scheme 900 according to some embodiments of the present disclosure, using a similar configuration as schemes 700 and 800 in FIGs. 7 and 8, but with a different method of selecting CSI-RS resource combinations from the list 710.
  • UE 115 is configured with the list 710 of CSI-RS resource combinations and a cycling pattern 920 as in FIG. 8.
  • the UE 115 may determine a CSI-RS resource combination to use for preparing the CSI report as in FIG. 8, but in addition to relying on a slot index, UE 115 may also rely on a slot offset, ⁇ n, indicated by, for example, a DCI signal 960.
  • the DCI signal 960 may also include the slot index for the starting combination 714. Aspects including the CSI-RS transmissions and CSI report preparation may remain the same as in FIG. 8, so only the way the UE selects a combination from the list 710 is described here.
  • the UE 115 may receive the DCI signal 960 at slot n 962, indicating a slot offset of ⁇ n as well as a slot index identifying the starting resource combination to be combination 714 from the list 710.
  • the slot offset ⁇ n from DCI 960 may cause the UE 115 to cycle through the cycling pattern 920 after the number of slots (i.e., n) indicated by the slot offset ⁇ n has passed, i.e., just prior to slot n + ⁇ n 964 at time 990. Since the DCI 960 included a slot index for starting combination 714 (corresponding to CSI-RS resource combination (3, 1) in the illustrated example) in the list 710, at time 990, the UE 115 will select combination 714.
  • the UE 115 After another n slots have elapsed (corresponding to a periodicity of T slots, as illustrated) , at time 992, the UE 115 will select the next combination 716 in the list 710 according to the cycling pattern previously provisioned. Similarly, after another n slots have elapsed at time 994, the UE 115 will select the next combination 712 in the list 710 according to the cycling pattern. And, in the illustrated example, after another n slots have elapsed at time 996, the UE will select combination 714 in the list 710 according to the cycling pattern.
  • FIG. 10 illustrates a flow diagram of a wireless communication method 1000 according to some embodiments of the present disclosure.
  • a wireless communication device such as a UE 115, utilizing one or more components, such as the processor 502, the memory 504, the channel state module 508, the transceiver 510, the modem 512, the one or more antennas 516, and various combinations thereof.
  • the UE 115 may be on an HST travelling within the range of two or more TRPs 205 on an SFN. For simplicity, the method is illustrated with only two TRPs 205, though a greater number of TRPs 205 may be possible.
  • the method 1000 includes a number of enumerated steps, but embodiments of the method 1000 may include additional steps before, during, after, and in between the enumerated steps. Further, in some embodiments, one or more of the enumerated steps may be omitted or performed in a different order.
  • UE 115 receives a CSI report configuration originating from a BS 105.
  • the CSI report may be transmitted by the BS 105 through the first and/or second TRP 205 (e.g., in an RRC signal) .
  • the configuration may include a plurality of sets of one or more CSI-RS (e.g., NZP-CSI-RS) resources, corresponding to a first CSI-RS to be transmitted by the first TRP 205 and a second CSI-RS to be transmitted by the second TRP 205.
  • the CSI report configuration may include a list of CSI-RS resource combinations and a cycling pattern, as described in further detail below.
  • UE 115 receives the first CSI-RS from the first TRP 205.
  • the first CSI-RS may originate at the BS 105 and may include a first scrambling ID.
  • the second CSI-RS may originate at the BS 105 and may include a second scrambling ID, different than the first scrambling ID of the first CSI-RS.
  • the method proceeds to block 1010. This may correspond, for example, to situations where the UE 115 will be selecting not only the resource combinations to use, but before that selecting what resource sets the UE 115 will need to test combinations for when measuring the channels.
  • the UE 115 may select a first resource set corresponding to the first CSI-RS (and the first TRP 205) , and a second resource set corresponding to the second CSI-RS (and the second TRP 205) .
  • the UE 115 may select two CSI-RS resources, one from each of the two sets selected at block 1010 and corresponding to the respective first and second CSI-RS. Each of the two resources may be associated with a different TCI state.
  • the UE 115 may use the selected CSI-RS resources to perform channel measurement using the received CSI-RS from each TRP and select parameters for beamforming the downlink (e.g., the PDSCH) from each of the two TRPs 205.
  • the UE 115 may determine CSI based on the selected CSI-RS resources and create a CSI report.
  • the CSI report may indicate which CSI-RS resources the UE 115 selected at block 1012, for example, by including a CRI for the first resource and a CRI for the second resource.
  • the CSI report may include a RI, which may indicate the same rank for the first and second CSI-RS resources.
  • the UE 115 may select a first set of precoders based on the first CSI-RS, and a second set of precoders based on the second CSI-RS.
  • the CSI report may include two precoder indicators (e.g., PMIs or i 1 s) , one for the first set of precoders and one for the second set of precoders.
  • UE 115 may determine a CQI for SFN transmission based on the CRIs, i1s, and RI and include the CQI in the CSI report.
  • the CQI may also be based on a coupling factor, ⁇ , across the two TRPs 205.
  • the method then proceeds to block 1032.
  • each combination may indicate two CSI-RS resources, one for the first CSI-RS from the first TRP 205, and one for the CSI-RS from the second TRP 205.
  • the method proceeds based on whether the UE 115 receives a slot offset (e.g., through dynamic signaling in a DCI originating at the BS 105 and transmitted through one of the TRPs 205) . If the UE 115 receives the slot offset, the method proceeds to block 1020. Otherwise, the method proceeds to block 1022.
  • a slot offset e.g., through dynamic signaling in a DCI originating at the BS 105 and transmitted through one of the TRPs 205
  • the UE 115 selects a CSI-RS resource combination from the list of CSI-RS resource combinations based on the slot offset and a cycling pattern (including a slot index) , as described in detail with respect to FIG. 9.
  • the cycling pattern may indicate the order in which the UE 115 should cycle through the CSI-RS resource combinations as it travels between TRPs 205, starting with a slot index.
  • a slot offset ⁇ n may indicate the number of slots that should elapse before the UE 115 starts with the first resource combination identified by the slot index. After n slots have elapses, the UE 115 will select the next combination in the list based on the cycling pattern.
  • the UE 115 may select a CSI-RS resource combination based the current slot index and a cycling pattern as described in detail in the discussion of FIG. 8. For example, each slot index (or a range of slot indices) may correspond to a combination in the list of CSI-RS resource combinations. The UE 115 may select a combination from the list based on the current slot index and cycling pattern. When the next slot index corresponds to a new combination, the UE 115 may select the new combination in the list based on the cycling pattern.
  • the method proceeds to block 1024.
  • the UE 115 may determine CSI based on the selected CSI-RS resource combination and create a CSI report.
  • the CSI report may include a RI, which may indicate the same rank for the first and second CSI-RS resources.
  • UE 115 may select a first set of precoders based on the first CSI-RS, and a second set of precoders based on the second CSI-RS, for example similar to as discussed with respect to block 1014 above.
  • the UE 115 may receive an indication (e.g., through a DCI message originating at BS 105 and transmitted through one or both TRPs 205) identifying which CSI-RS resource combination to select from the list of CSI-RS resource combinations.
  • the indication may be in the form of an index into the list. Though illustrated after having received the CSI-RS, in some embodiments this will have been received prior to the CSI-RS reception, in which case at block 1028 the UE 115 accesses the resource combination that had been previously indicated to now use it.
  • the UE 115 may determine the CSI based on the indicated CSI-RS resource combination and create a CSI report, similar to as discussed above with respect to blocks 1024 and 1014. The method then proceeds to block 1032.
  • the UE 115 transmits the CSI report to the BS 105 through one or both TRPs 205, for the BS 105 to use in determining how to beamform the downlink channel from each TRP 205 to the UE 115.
  • FIG. 11 illustrates a flow diagram of a wireless communication method 1100 according to some embodiments of the present disclosure. Aspects of the method 1100 can be executed by a wireless communication device, such as a BS 105, utilizing one or more components, such as the processor 602, the memory 604, the channel state module 608, the transceiver 610, the modem 612, the one or more antennas 616, and various combinations thereof.
  • the BS 105 may be communicating with a UE on an HST travelling within the range of two or more TRPs 205 on an SFN. For simplicity, the method is illustrated with only two TRPs 205, though a greater number of TRPs 205 may be possible.
  • the method 1100 includes a number of enumerated steps, but embodiments of the method 1100 may include additional steps before, during, after, and in between the enumerated steps. Further, in some embodiments, one or more of the enumerated steps may be omitted or performed in a different order.
  • the BS 105 selects a first CSI-RS for a UE 115 to use in determining CSI and beamforming parameters.
  • the first CSI-RS may be, for example, an NZP-CSI-RS.
  • the BS 105 selects a second CSI-RS for the UE 115 to use in determining CSI and beamforming parameters.
  • the second CSI-RS may be, for example, an NZP-CSI-RS.
  • the first and second CSI-RS may have different identifiers (e.g., scrambling identifiers) from each other according to embodiments of the present disclosure.
  • the BS 105 may prepare and transmit a CSI configuration intended for a UE 115 to use in preparing a CSI report.
  • the CSI configuration may include a plurality of sets of one or more CSI-RS (e.g., NZP-CSI-RS) resources, a subset of which will correspond to the first and second CSI-RSs selected by the BS 105 at blocks 1102 and 1104 when transmitted.
  • the CSI report configuration may include a list of CSI-RS resource combinations, and yet in further embodiments also a cycling pattern. The cycling pattern indicates how the UE 115 may cycle through CSI-RS resource combinations in the list over time.
  • the BS 105 may dynamically transmit signals to the UE (e.g., in a DCI, through one or both TRPs 205) to guide the UE in selecting a CSI-RS resource combination from the list of CSI-RS resource combinations.
  • the BS 105 may transmit an indication (e.g., an index) to the UE identifying which CSI-RS resource combination from the list of CSI-RS resource combinations should be used.
  • the BS 105 may transmit cycling pattern and a slot index. The slot index may indicate which resource combination the UE 115 should select as the first combination, after which the cycling pattern will dictate what combination comes next.
  • the BS 105 may further transmit a slot offset which identifies a ⁇ n of slots, after which the first resource combination identified by the slot index should be selected and used. After that, the cycling pattern will identify how long to stay with that resource combination from the list (aperiodicity) before transitioning to the next resource combination from the list.
  • the BS 105 may transmit the first CSI-RS to the first TRP, which the first TRP may ultimately deliver to the UE 115.
  • the BS 105 may do so using a first resource.
  • the BS 105 may transmit the CSI-RS to the second TRP, which the second TRP may ultimately deliver to the UE 115.
  • the BS 105 may do so using a second resource.
  • the BS 105 may receive a CSI report based on the first and second CSI-RSs.
  • the CSI report may originate at the UE 115 and may be received from the first and/or second TRP 205.
  • the CSI report may indicate (e.g., by including CRIs) which CSI-RS resources from each CSI-RS the UE 115 selected for determining CSI.
  • Each of the selected CSI-RS resources may be associated with a different TCI state.
  • the CSI report may also include an RI, which may indicate the same rank for the first and second CSI-RS resources.
  • the CSI report may also include a first set of precoders based on the first CSI-RS, and a second set of precoders based on the second CSI-RS.
  • the CSI report may include two precoder indicators (e.g., PMIs or i 1 s) , one for the first set of precoders and one for the second set of precoders.
  • the CSI report may also include a CQI for SFN transmission based on the CRIs, i1s, RI and/or a coupling factor across the first and second TRPs 205.
  • Information and signals may be represented using any of a variety of different technologies and techniques.
  • data, instructions, commands, information, signals, bits, symbols, and chips that may be referenced throughout the above description may be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof.
  • a general-purpose processor may be a microprocessor, but in the alternative, the processor may be any conventional 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, multiple microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration) .
  • the functions described herein may be implemented in hardware, software executed by a processor, firmware, or any combination thereof. If implemented in software executed by a processor, the functions may be stored on or transmitted over as one or more instructions or code on a computer-readable medium. Other examples and implementations are within the scope of the disclosure and appended claims. For example, due to the nature of software, functions described above can be implemented using software executed by a processor, hardware, firmware, hardwiring, or combinations of any of these. Features implementing functions may also be physically located at various positions, including being distributed such that portions of functions are implemented at different physical locations.
  • “or” as used in a list of items indicates an inclusive list such that, for example, a list of [at least one of A, B, or C] means A or B or C or AB or AC or BC or ABC (i.e., A and B and C) .

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Abstract

L'invention concerne des dispositifs, des systèmes et des procédés de communication sans fil se rapportant à des mécanismes pour fournir une rétroaction d'informations d'état de canal dans un réseau à fréquence unique (SFN) de train à grande vitesse (HST). Un équipement utilisateur (UE) reçoit un premier signal de référence d'un premier point d'émission et de réception (TRP) et un second signal de référence d'un second TRP, chaque signal de référence ayant un identifiant différent. L'UE effectue une estimation de canal sur chaque signal de référence séparément et sélectionne des ressources de signal de référence et des paramètres de formation de faisceau correspondant à chaque signal de référence, sur la base des résultats de l'estimation de canal. L'UE crée ensuite un rapport d'information sur l'état du canal (CSI) comprenant les ressources du signal de référence, les paramètres de formation de faisceau et les résultats de l'estimation du canal et transmet le rapport à chaque TRP pour utilisation dans la communication SFN.
PCT/CN2020/085318 2020-04-17 2020-04-17 Rétroaction de csi dans des réseaux à haute fréquence de train à grande vitesse WO2021208069A1 (fr)

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WO2023200218A1 (fr) * 2022-04-12 2023-10-19 Samsung Electronics Co., Ltd. Sélection et rapport de sous-ensemble de trp

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