Downlink channel state information computation and reporting method

Abstract

A method of downlink channel state information (DL CSI) computation and reporting is proposed to support high speed scenarios in new radio (NR) systems. In a first novel aspect, two CSI reference slots are defined. A CSI reference slot for CSI measurement is defined to determine which CSI-RS / SSB occasion to use for CSI computation. A CSI reference slot for CSI computation is defined to determine which slot the UE assumes the CSI computation should be based on, the channel at that time or the channel after that. In a second novel aspect, the UE can be configured with a CSI computation period consisting of one or N slots and can be divided into multiple non-overlapping sub-periods. The UE can be configured to compute and report wideband and subband CSI for the entire CSI computation period and / or for each sub-period.

Description

[0001] Cross-reference to related applications

[0002] This application claims priority to U.S. Provisional Application No. 63 / 218,439, filed July 5, 2021, entitled “CSI Codebook Design for High Mobility”, and U.S. Provisional Application No. 63 / 218,438, filed July 5, 2021, entitled “Extension of CSI Framework to Support High Mobility”, the subject of which is incorporated herein by reference. Technical Field

[0003] The disclosed embodiments generally relate to mobile communication networks, and more specifically to methods for supporting high-speed channel state information (CSI) calculation. Background Technology

[0004] Fifth generation new radio (5G NR) is an improved radio access technology (RAT) that offers higher data rates, greater reliability, lower latency, and improved system capacity. In an NR system, the terrestrial radio access network comprises multiple base stations (BSs), called next-generation node-Bs (gNBs), which communicate with multiple mobile stations (called user equipment (UEs)). UEs can communicate with the BS or gNB via downlink (DL) and uplink (UL). DL refers to communication from the base station to the UE. UL refers to communication from the UE to the base station. The 5G NR standard is defined by 3GPP. The UE uses a Channel State Information reference signal (CSI-RS) to measure and feedback the characteristics of the radio channel so that the gNB can perform DL data transmission using the correct modulation, code rate, beamforming, etc.

[0005] In practical development, a significant drop in throughput was observed in high-speed or medium-speed scenarios. A major reason is that reported CSIs become outdated due to rapid channel changes. Channel changes can be observed in the Doppler domain. In the current NR, CSIs are calculated based on the time slot where the CSI reference resource is located, which precedes the uplink time slot used for CSI reporting. When the gNB needs to perform scheduling, CSIs calculated for past time slots may be useless later, especially in high-speed scenarios. To improve throughput, the gNB needs to know CSIs that are beneficial for "future" channels. Future CSIs cannot be learned through "one-off" measurements because any channel change requires at least two measurements to detect.

[0006] We are seeking a solution to extend the CSI framework in NR to support high-speed scenarios. Summary of the Invention

[0007] A novel method for calculating and reporting downlink channel state information (DLCSI) is proposed to support high-speed scenarios in NR systems. In a first novel aspect, two CSI reference time slots are defined. A CSI reference time slot for CSI measurement is defined to determine which CSI-RS / SSB timing to use for CSI calculation. A CSI reference time slot for CSI calculation is defined to determine the time slot from which the UE assumes the CSI calculation should be based on the channel. In a second novel aspect, the UE can be configured with a CSI calculation period consisting of one or N time slots, and can be divided into multiple non-overlapping sub-periods. The UE can be configured to calculate and report the broadband CSI and subband CSI for the entire CSI calculation period and / or each sub-period.

[0008] In one embodiment, the UE receives CSI-RS configuration information from the BS. The UE determines a first CSI reference time slot for measurement and a second CSI reference time slot for calculation based on the CSI-RS configuration information. The second CSI reference time slot appears after the first CSI reference time slot in the time domain. The UE measures the CSI-RS of the downlink channel received before the first CSI reference time slot for measurement. The UE calculates the CSI of the downlink channel based on the second CSI reference time slot for calculation. The UE estimates and predicts the CSI of the downlink channel starting from the second CSI reference time slot for calculation.

[0009] In another embodiment, the UE receives CSI-RS configuration information from the base station (gNB). The CSI-RS configuration includes CSI-RS resources and a CSI calculation period having one or more non-overlapping sub-periods within the CSI calculation period in the time domain. The UE measures multiple timings of the CSI-RS for the downlink channel received through the configured CSI-RS resources. The UE uses the timing correlation of the multiple timings of the CSI-RS to estimate the CSI of the downlink channel used for the CSI calculation period. The UE reports the estimated CSI of the downlink channel to the gNB, and the estimated CSI is reported according to the configured CSI calculation period.

[0010] According to the downlink channel state information calculation and reporting method and user equipment provided by the present invention, the CSI of future DL channels can be calculated and predicted based on channel changes detected from multiple CSI-RS measurements.

[0011] Other embodiments and advantages are described in the detailed description below. This summary portion is not intended to define the invention. The invention is defined by the claims. Attached Figure Description

[0012] Figure 1 The illustration depicts an NR mobile communication network based on a novel aspect, featuring high-speed CSI-RS measurement, calculation, and reporting.

[0013] Figure 2 This is a simplified block diagram of a base station and user equipment implementing certain embodiments of the present invention.

[0014] Figure 3 The diagram illustrates the sequence flow of the entire process for CSI acquisition and reporting according to a novel aspect.

[0015] Figure 4 A first embodiment of a CSI reference time slot for measurement and a CSI reference time slot for calculation, based on a novel aspect, is shown to support high-speed scenarios.

[0016] Figure 5 The illustration shows a second embodiment of configuring the CSI computation cycle with full-cycle CSI and sub-cycle CSI according to a novel aspect to support high-speed scenarios.

[0017] Figure 6 The illustration shows an example of CSI calculation cycles with full-cycle CSI and sub-cycle CSI for broadband and sub-band.

[0018] Figure 7 The illustration shows an example of CSI calculations and reporting based on a novel aspect to support high-speed scenarios.

[0019] Figure 8This is a flowchart of a method for using CSI reference time slots for measurement and CSI reference time slots for calculation to support high-speed scenarios, based on a novel application.

[0020] Figure 9 This is a flowchart of a novel approach to configuring the CSI calculation cycle from the UE's perspective to support high-speed scenarios. Detailed Implementation

[0021] Reference will now be made in detail to some embodiments of the invention, examples of which are shown in the accompanying drawings.

[0022] Figure 1 The illustration depicts an NR mobile communication network 100 with high-speed CSI-RS measurement, calculation, and reporting according to a novel aspect. The mobile communication network 100 is an OFDM network comprising a serving base station (gNB 101) and user equipment (UE 102). In a 3GPP NR system based on OFDMA downlink, radio resources are divided into multiple time slots in the time domain, each time slot consisting of multiple OFDMA symbols. Each OFDMA symbol is further composed of multiple OFDMA subcarriers in the frequency domain, depending on the system bandwidth. The basic unit of the resource grid is called a resource element (RE), which spans one OFDMA symbol on one OFDMA subcarrier. REs are grouped into resource blocks (RBs), where each RB consists of twelve consecutive subcarriers in one time slot.

[0023] Several physical downlink channels and reference signals are defined to carry information originating from higher layers using a set of resource elements. For downlink channels, the Physical Downlink Shared Channel (PDSCH) is the primary data-carrying downlink channel in NR, while the Physical Downlink Control Channel (PDCCH) carries downlink control information (DCI). Control information may include scheduling decisions, information related to reference signal information, rules for forming the corresponding transport blocks (TBs) to be carried by the PDSCH, and power control commands. For radio resource management (RRM) measurements in NR, each UE can be configured to measure synchronization signal (SS) blocks (SSBs) and / or CSI-RS. For CSI-RS measurements, frequency and timing resources need to be determined. The UE uses CSI-RS measurements to evaluate and feedback the characteristics of the DL channel so that the gNB can perform DL data transmission using the correct modulation, code rate, beamforming, etc.

[0024] In actual development, a significant drop in throughput was observed in high-speed or medium-speed scenarios. A major reason is that reported CSIs become outdated due to rapid channel changes. According to a novel aspect, such as... Figure 1 As shown, a CSI acquisition and reporting approach is proposed to support high-speed scenarios. In a novel aspect, two CSI reference time slots are defined. One CSI reference time slot for CSI measurement is defined to determine which / which CSI-RS / SSB timings to use for CSI calculation. The other CSI reference time slot for CSI measurement is defined to determine the first time slot from which the UE assumes CSI calculation should be based on the channel starting from that time slot. For example, if CSI reporting occurs in time slot (n), then the CSI reference time slot for CSI measurement occurs in time slot (nn). CSI_REF The CSI reference slot used for calculation appears in slot (n+K). In another novel aspect, the UE can be configured with a CSI calculation period consisting of one or N slots, and can be divided into multiple non-overlapping sub-periods. The UE can be configured to calculate and report broadband CSI and subband CSI for the entire CSI calculation period and / or each sub-period.

[0025] Figure 2This is a simplified block diagram of a base station 201 and a user equipment 211 executing certain embodiments of the present invention in a mobile communication network 200. For the base station 201, an antenna 221 transmits and receives radio signals. An RF transceiver module 208 is coupled to the antenna, receives RF signals from the antenna, converts them into baseband signals, and sends the baseband signals to a processor 203. The RF transceiver 208 also converts baseband signals received from the processor into RF signals and sends them to the antenna 221. The processor 203 processes the received baseband signals and invokes different functional modules to perform functions in the base station 201. The memory 202 includes volatile computer-readable storage media and non-volatile computer-readable storage media, storing program instructions and data 209 to control the operation of the base station.

[0026] A similar configuration exists in UE 211, where antenna 231 transmits and receives RF signals. RF transceiver module 218 is coupled to the antenna, receives RF signals from the antenna, converts them into baseband signals, and sends the baseband signals to processor 213. RF transceiver 218 also converts baseband signals received from the processor into RF signals and sends them to antenna 231. Processor 213 processes the received baseband signals and calls different functional modules to perform functions in UE 211. Memory 212 includes volatile computer-readable storage media and non-volatile computer-readable storage media, storing program instructions and data 219 to control the operation of the UE.

[0027] Base station 201 and UE 211 also include several functional modules and circuits to perform some embodiments of the present invention. Different functional modules are circuits that can be configured and implemented by software, firmware, hardware, or any combination thereof. When executed by processors 203 and 213 (e.g., by executing program codes 209 and 219), the functional modules and circuits, for example, allow base station 201 to schedule (via scheduler 204), precode (via precoder 205), encode (via MIMO encoding circuitry 206), and send control / configuration information and data (via control / configuration circuitry 207) to UE 211, and allow UE 211 to receive control / configuration information and data (via control / configuration circuitry 217), measure CSI reference signals (via measurement circuitry 216), estimate CSI (via estimation circuitry 215), and report the estimated CSI accordingly (via reporting circuitry 220).

[0028] Figure 3The diagram illustrates the sequence flow of the entire process for CSI acquisition and reporting according to a novel aspect. In step 311, gNB 301 provides CSI configuration information to UE 302 for CSI acquisition and reporting. The CSI configuration information may include CSI reference signal configuration, CSI reference resource configuration, CSI reporting configuration, CSI reference time slots for CSI measurement, CSI reference time slots for CSI calculation, and CSI calculation period, etc. In step 312, gNB 301 correspondingly transmits multiple opportunities for CSI reference signals to UE 302 via the configured CSI-RS resources. In step 321, UE 302 receives the multiple opportunities for CSI reference signals, estimates the effective downlink channel, and performs CSI calculation based on the CSI configuration information.

[0029] In a novel aspect, two CSI reference time slots are defined. A CSI reference time slot for CSI measurement is defined to determine which CSI-RS is used to calculate the CSI. A CSI reference time slot for CSI calculation is defined to determine the first time slot of the channel from which the UE assumes the CSI calculation should be based. In another novel aspect, the UE 302 can be configured by the gNB 301 to have a CSI calculation period consisting of one or N time slots, and can be divided into multiple non-overlapping sub-periods. In step 322, the UE 302 reports the calculated CSI to the gNB based on the CSI configuration information. The reported CSI parameters may include a Rank Indicator (RI), a Precoding Matrix Indicator (PMI), and a Channel Quality Index (CQI). In step 331, the gNB 301 receives CSI feedback and determines scheduling parameters for subsequent PDSCH transport block (TB) transmissions. In step 341, gNB 301 transmits data to UE 302 via PDSCH using determined parameters including modulation, code rate, and beamforming.

[0030] Figure 4A first embodiment of a CSI reference time slot for measurement and a CSI reference time slot for calculation, based on a novel aspect, is illustrated to support high-speed scenarios. CSI-RS is a dedicated measurement signal introduced for the UE to acquire CSI, for example, for channel-related scheduling, link adaptation, and transmission settings related to multi-antenna transmission. The UE is configured to calculate CSI based on a single timing or multiple CSI-RS timings on configured CSI reference resources (e.g., a set of downlink frequency and time domain resource blocks). The CSI reference resources of the serving cell are defined as follows: In the frequency domain, the CSI reference resources are defined by a set of downlink physical resource blocks corresponding to the frequency band associated with the derived CQI value. In the time domain, the CSI reference resources are defined by a single downlink time slot or specific subframe associated with the derived CQI value. In the spatial / layer domain, the CSI reference resources are defined by any RI and PMI conditioned on the CQI.

[0031] In the current NR, CSI is calculated based on the time slot where the CSI reference resource is located, which precedes the uplink time slot used for CSI reporting. However, CSI calculated for past time slots may be useless later when the gNB needs to perform scheduling, especially in high-speed scenarios. To improve throughput, the gNB needs to know the CSI for "future" channels when channel changes are significant. Future CSI cannot be learned through a "one-off" measurement because any channel change requires at least two measurements to detect. In a novel aspect, the UE can be configured to measure CSI-RS multiple times over multiple time slots of past DL channels, and the UE can also be configured to calculate and predict the CSI for future DL channels based on channel changes detected from multiple CSI-RS measurements.

[0032] Specifically, two CSI reference time slots are defined to support high-speed scenarios. A CSI reference time slot for CSI measurement is defined to determine which CSI-RS is used to calculate the CSI. A CSI reference time slot for CSI calculation is defined to determine the first time slot the UE assumes the CSI calculation should be based on the current channel. When the UE is configured to calculate CSI based on a single CSI-RS timing, the two CSI reference time slots overlap and are identical to the Rel-15NR CSI reference resource. When the UE is configured to calculate CSI based on multiple CSI-RS timings, the CSI reference time slot for CSI measurement is identical to the Rel-15NR CSI reference resource to determine which CSI-RS timings(s) to use for CSI calculation. When the UE is configured to calculate CSI based on multiple CSI-RS timings, the CSI reference time slot for CSI calculation can be configured to be the same as or after the uplink time slot used for CSI reporting. Multiple CSI-RS opportunities can be multiple repetitions within a burst cycle, or multiple CSI-RS resources in a cross-timeslot CSI-RS resource set no later than the CSI reference resource.

[0033] exist Figure 4 In this embodiment, the UE is configured to calculate CSI based on multiple timings of CSI-RS and report the CSI at time slot n. The CSI reference time slot used for CSI measurement is at an offset value of n. CSI_ref The CSI reference resources that appear before slot n are the same, for example, those that appear in slot (nn) CSI_ref In other words, the UE is based on no later than the time slot (nn). CSI_ref The CSI is calculated at multiple times based on the received and measured CSI-RS. The CSI reference time slot used for CSI calculation can be configured after the uplink time slot used for CSI reporting with an offset K (e.g., at time slot (n+K)). That is, the CSI calculated by the UE is for a future time, starting from time slot (n+K), where the UE assumes that the CSI calculation should be predicted on the channel starting from a future time of time slot (n+K). Traditionally, due to rapid channel changes, past CSI reference resources (e.g., time slot (n+K)) are limited. CSI_ref) The CSI calculated on the time slot becomes outdated for future times (e.g., time slot (n+K)). By configuring two separate CSI reference time slots for CSI measurement and CSI calculation, the UE can calculate the CSI based on a time slot no later than (n+K). CSI_ref The calculation and prediction of future CSI in slots (n+K) based on multiple moments of received and measured CSI-RS is performed. For example, CSI prediction can use an autoregressive (AR) model. Execution. Multiple CSI-RS measurements can be used to estimate the AR coefficient {ci}. This equation can then be applied recursively. Calculate H[n+K].

[0034] Figure 5 The illustration shows a second embodiment of configuring a CSI calculation cycle with full-cycle CSI and sub-cycle CSI according to a novel aspect to support high-speed scenarios. The UE can be configured with a CSI calculation cycle consisting of one or more time slots, and can be divided into multiple non-overlapping sub-cycles. Each sub-cycle consists of X consecutive time slots, where X is configurable. The CSI calculated for the entire CSI calculation cycle is called the "full-cycle" CSI. The CSI calculated for a sub-cycle is called the "sub-cycle" CSI. A CSI calculation cycle can begin from a CSI reference time slot used for CSI calculation. The CSI calculation cycle can be set before the CSI resource reference specified in NR Release 15.

[0035] exist Figure 5 In the example, sub-cycles SUB-P 0, SUB-P 1, ..., SUB-P P-1 are defined in the time domain. Subbands SUB-B 0, SUB-B 1, ..., SUB-B B-1 are defined in the frequency domain. The size of a sub-cycle depends on the total number of slots in the CSI calculation period. If the number of slots in CSI calculation period A is greater than the number of slots in CSI calculation period B, then the sub-cycle size of A is greater than or equal to the sub-cycle size of B. When the number of slots in a CSI calculation period is less than or equal to a predefined value, only full-cycle CSI is reported. If none of the slots in a CSI calculation period include at least one downlink or variable symbol configured by a higher layer, then the full-cycle CSI report is omitted. A valid sub-cycle is a sub-cycle in which all slots include at least one downlink or variable symbol configured by a higher layer. If a sub-cycle is not a valid sub-cycle, then the sub-cycle CSI report is omitted. Starting from the first valid sub-cycle, only valid sub-cycles are indexed. The gNB can notify the UE which sub-cycles(s) can be omitted for CSI reporting. Omitted sub-periods are considered invalid sub-periods.

[0036] In a preferred embodiment, the CSI report is configured to occur in time slot n, and the CSI calculation cycle begins from the CSI reference time slot used for CSI calculation, for example, time slot (n+K), such as... Figure 5 As shown. Because the UE is configured to be based on no later than the time slot (nn) CSI refThe UE calculates the CSI at multiple points in the measured CSI-RS. The UE can consider the temporal correlation of these multiple points in the CSI-RS to predict the CSI in slots (n+K). Furthermore, utilizing temporal correlation, the UE is configured with a CSI calculation period (e.g., spanning multiple slots) having one full period and multiple non-overlapping sub-periods. The CSI calculation period is designed to help reduce CSI feedback overhead. If N slots within the same sub-period can share the same CSI with minimal performance loss, the overhead is reduced to 1 / N. Moreover, channel variations over time are typically sparse in the transform domain (e.g., the Doppler domain (via DFT)). The M sub-periods can then be described using M′ << M values ​​(e.g., M′ / M = 1 / 4).

[0037] In another alternative embodiment, the CSI report is configured to occur in time slot n, and the CSI calculation cycle ends at the CSI reference time slot used for the CSI measurement, which is the same as the CSI reference resource, for example, time slot (nn). CsI_ref (Not shown). The goal is to enable the gNB to predict future CSI, therefore the UE should calculate the CSI only based on past observations. In this case, the UE measurement is no later than the time slot (nn). CSI_ref The UE receives the CSI-RS and calculates the CSI using a calculation period ending in the same time slot. The UE still considers the temporal correlation of the entire calculation period to estimate the CSI of the DL channel, while reducing CSI feedback overhead. However, the UE does not need to make any predictions about the CSI of the DL channel starting from a future time slot (n+K). The UE simply reports the calculated past CSI to the network, and the network can use the received past CSI to predict future CSI.

[0038] Figure 6 The illustration shows an example of CSI calculation cycles with full-cycle CSI and sub-cycle CSI for both broadband and subband. The gNB can be configured to calculate different combinations of CSI for the UE. For example... Figure 6 As shown in (a), the UE can be configured to calculate the broadband CSI for the entire CSI calculation cycle. The UE assumes that the gNB will apply the calculated CSI to the entire bandwidth throughout the entire CSI calculation cycle. Figure 6 As shown in (b), the UE can be configured to calculate the subband CSI for the entire CSI calculation period. For each subband CSI, the UE assumes that the gNB will apply the calculated CSI to the reference subband throughout the entire CSI calculation period. In this example, three subbands, SUB-B 0, SUB-B 1, and SUB-B 2, are defined, and the UE is configured to calculate the subband CSI for SUB-B 0, SUB-B 1, and SUB-B 2 throughout the entire CSI calculation period.

[0039] like Figure 6 As depicted in (c), the UE can be configured to calculate the broadband CSI for each sub-cycle. The UE assumes that the gNB will apply each calculated CSI to the entire bandwidth in the reference sub-cycle. In this example, three sub-cycles, SUB-P 0, SUB-P 1, and SUB-P 2, are defined, and the UE is configured to calculate the CSI for the entire bandwidth in each of the three sub-cycles, SUB-P 0, SUB-P 1, and SUB-P 2. Figure 6 As shown in (d), the UE can be configured to calculate the subband CSI for each sub-cycle. The UE assumes that the gNB will use each calculated CSI for the reference subband in the reference sub-cycle. In this example, three subbands SUB-B0, SUB-B1, and SUB-B2 are defined, and three sub-cycles SUB-P0, SUB-P1, and SUB-P2 are defined. The UE is configured to calculate the subband CSI (0-8) for SUB-B0, SUB-B1, and SUB-B2 in the three sub-cycles SUB-P0, SUB-P1, and SUB-P2.

[0040] Figure 7 The illustration shows an example of CSI calculation and reporting based on a novel aspect to support high-speed scenarios. In one embodiment, the gNB can inform the UE which sub-cycles(s) can be omitted for CSI reporting. Omitted sub-cycles are considered invalid sub-cycles. Figure 7 In example (a), sub-cycles 1 and 5 are omitted according to the gNB notification, and sub-cycle 2 is omitted because no time slot includes at least one downlink or variable symbol configured by a higher layer. Therefore, the UE only needs to report the sub-cycle CSI for SUB-P 0(0), SUB-P 3(1), and SUB-P 4(2). In another embodiment, the gNB can configure the UE to report the sub-cycle CQI only for the best K sub-cycles in the CSI calculation period, where K is configurable. Figure 7 In the example of (b), the CQI of each sub-cycle of sub-cycles 1, 2, and 4 is superior to the CQI of sub-cycles 0, 3, and 5. If K = 3, the UE only reports the CQI of sub-cycles SUB-P 1(0), SUB-P 2(1), and SUB-P 4(2). In one embodiment, the number of reported sub-cycles can be determined by the UE. The reported CSI consists of two phases, in which the UE reports the selected number of sub-cycles in the first phase.

[0041] In one example, the UE reports the sub-period CQI by transmitting the quantization difference between the signaled and full-period CQI. In another example, the UE reports the sub-period RI by transmitting the difference between the signaled and full-period RI. In yet another example, the sub-period PMI shares the same basis vector as the full-period PMI. The coefficients of the sub-period PMI are reported by transmitting the quantization difference between the coefficients of the full-period PMI and the amplitude and phase.

[0042] In one example, for semi-persistent CSI reporting on PUSCH, the configuration of the CSI calculation period (e.g., the number of slots) can be updated via an activated DCI scrambled with SP-CSI-RNTI. In another example, for semi-persistent CSI reporting on PUCCH, the configuration of the CSI calculation period (e.g., the number of slots) can be updated via an activation command (e.g., the number of slots). In yet another example, for non-periodic CSI reporting, the configuration of the CSI calculation period (e.g., the number of slots) can be updated by triggering a DCI update.

[0043] Figure 8 This is a flowchart of a method for using a novel application of CSI reference time slots for measurement and CSI reference time slots for calculation to support high-speed scenarios. In step 801, the UE receives CSI-RS configuration information from the BS. In step 802, the UE determines a first CSI reference time slot for measurement and a second CSI reference time slot for calculation from the CSI-RS configuration information. The second CSI reference time slot appears after the first CSI reference time slot in the time domain. In step 803, the UE measures the CSI-RS of the downlink channel received before the first CSI reference time slot for measurement. In step 804, the UE calculates the CSI of the downlink channel based on the second CSI reference time slot for calculation. The UE estimates and predicts the CSI of the downlink channel starting from the second CSI reference time slot for calculation.

[0044] Figure 9 This is a flowchart of a method for configuring CSI calculation periods to support high-speed scenarios based on a novel aspect. In step 901, the UE receives CSI-RS configuration information from the base station (gNB). The CSI-RS configuration includes CSI-RS resources and CSI calculation periods having one or more non-overlapping sub-periods within the CSI calculation period in the time domain. In step 902, the UE measures multiple timings of the CSI-RS for the downlink channel received through the configured CSI-RS resources. In step 903, the UE estimates the CSI of the downlink channel for the CSI calculation period using the timing correlation of the multiple timings of the CSI-RS. In step 904, the UE reports the estimated CSI of the downlink channel to the gNB and reports the estimated CSI according to the configured CSI calculation period.

[0045] Although the invention has been described in conjunction with certain specific embodiments for illustrative purposes, the invention is not limited thereto. Therefore, various modifications, alterations, and combinations of the features of the described embodiments can be implemented without departing from the scope of the invention as set forth in the claims.

Claims

1. A method for calculating and reporting downlink channel state information, comprising: The user equipment receives channel state information configuration information from the base station, wherein the configuration includes channel state information reference signal (CSI-RS) resources and the CSI calculation period in the time domain having one or more non-overlapping sub-periods; Measure multiple timings of CSI-RS received via the configured CSI-RS resources on the downlink channel; Estimate the CSI of the downlink channel for the CSI calculation period, wherein the user equipment estimates the CSI by considering the timing correlation of the multiple timings of the CSI-RS; as well as The estimated CSI of the downlink channel is reported to the base station, wherein the estimated CSI is reported based on the CSI calculation period.

2. The method of claim 1, wherein, The estimated CSI of the downlink channel includes at least one of the rank indicator, precoding matrix indicator, and channel quality indicator to the base station.

3. The method of claim 2, wherein, The CSI includes the sub-period CSI estimated for each sub-period and the full-period CSI for calculating the period estimate of the CSI.

4. The method of claim 3, wherein, Sub-period CQI is reported by sending a signal to quantize the difference between the signal and the full-period CQI.

5. The method of claim 3, wherein, The user equipment reports the best K sub-cycle CSIs in the entire CSI calculation cycle, where K is an integer configured by the base station.

6. The method of claim 1, wherein, The CSI calculation cycle is set before the CSI resource reference associated with the configured CSI-RS resource.

7. The method of claim 1, wherein, The user equipment is configured to report the CSI in a CSI reporting slot, wherein the CSI calculation cycle begins at an offset after the CSI reporting slot.

8. The method according to claim 7, characterized in that, The user equipment uses the timing correlation of multiple timings of the CSI-RS to predict the CSI of the downlink channel.

9. A user equipment for calculating and reporting downlink channel state information, comprising: The receiver receives channel state information configuration information from the base station, wherein the configuration includes channel state information reference signal (CSI-RS) resources and the CSI calculation period having one or more non-overlapping sub-periods in the time domain. Measurement circuitry measures multiple timings of CSI-RS received via the configured CSI-RS resources on the downlink channel. CSI processing circuitry estimates the CSI of the downlink channel for the CSI calculation period, wherein the user equipment estimates the CSI by considering the timing correlation of the multiple timings of the CSI-RS; as well as The transmitter sends the estimated CSI of the downlink channel to the base station, wherein the estimated CSI is reported based on the CSI calculation period.

10. The user equipment of claim 9, wherein, The estimated CSI of the downlink channel includes at least one of the rank indicator, precoding matrix indicator, and channel quality indicator to the base station.

11. The user equipment of claim 10, wherein, The CSI includes the sub-period CSI estimated for each sub-period and the full-period CSI for calculating the period estimate of the CSI.

12. The user equipment of claim 11, wherein, Sub-period CQI is reported by sending a signal to quantize the difference between the signal and the full-period CQI.

13. The user equipment according to claim 11, characterized in that, The user equipment reports the best K sub-cycle CSIs in the entire CSI calculation cycle, where K is an integer configured by the base station.

14. The user equipment of claim 9, wherein, The CSI calculation cycle is set before the CSI resource reference associated with the configured CSI-RS resource.

15. The user equipment of claim 9, wherein, The user equipment is configured to report the CSI in a CSI reporting slot, wherein the CSI calculation cycle begins at an offset after the CSI reporting slot.

16. The user equipment of claim 15, wherein, The user equipment uses the timing correlation of multiple timings of the CSI-RS to predict the CSI of the downlink channel.

17. A method for calculating and reporting downlink channel state information, comprising: The base station sends channel state information configuration information to the user equipment, wherein the configuration includes channel state information reference signal (CSI-RS) resources and the CSI calculation period in the time domain having one or more non-overlapping sub-periods; Multiple opportunities to send CSI-RS to the user equipment via the configured CSI-RS resources of the downlink channel; Receive the estimated CSI of the downlink channel based on the CSI calculation period, wherein the CSI is estimated using the timing correlation of the multiple timings of the CSI-RS; as well as Data transmission to the user equipment is scheduled using the estimated CSI reported by the user equipment, wherein the estimated CSI is reported based on the CSI calculation period.

18. The method of claim 17, wherein, The estimated CSI of the downlink channel includes at least one of the rank indicator, precoding matrix indicator, and channel quality indicator to the base station.

19. The method of claim 17, wherein, The CSI includes the sub-period CSI estimated for each sub-period and the full-period CSI for calculating the period estimate of the CSI.

20. The method of claim 17, wherein, The base station uses the reported CSI, estimated for the CSI calculation period, to predict the CSI of the downlink channel at a later time.

21. A non-volatile computer-readable storage medium storing program instructions and data, which, when executed by a processor of a user equipment used for downlink channel state information calculation and reporting, cause the user equipment to perform the method as described in any one of claims 1-8, 17-20.

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