阅读说明：本技术 用于波束报告的测量周期 (Measurement period for beam reporting ) 是由 李华 崔杰 唐扬 张羽书 M·拉加万 于 2019-08-09 设计创作，主要内容包括：在NR中,gNB利用多个天线和波束形成技术来向UE进行下行链路传输。本文描述了UE测量从gNB接收的多个定向波束的质量所采用的方法和装置。(In NR, the gNB utilizes multiple antennas and beamforming techniques for downlink transmission to the UE. Methods and apparatus employed by a UE to measure quality of a plurality of directional beams received from a gNB are described herein.)

1. An apparatus for a User Equipment (UE), the apparatus comprising:

a memory and a processing circuit, wherein the processing circuit is to:

measuring Reference Signal Received Power (RSRP) of one or more channel state information reference signals (CSI-RSs), wherein the CSI-RSs are transmitted via different directional beams from a next generation evolved node B (gNB);

for a particular directional beam, calculating an average of a plurality of RSRPs of the CSI-RSs associated with the particular beam received at different times; and the number of the first and second electrodes,

encoding a beam report for transmission to the gNB, the beam report comprising the average RSRP of one or more CSI-RSs associated with one or more beams.

2. The apparatus of claim 1, wherein the processing circuitry is to periodically encode the beam report for transmission to the gNB according to a reporting period.

3. The apparatus of claim 2, wherein the processing circuit applies a sliding window to calculate an average when the reporting period is less than a beam measurement period required to calculate an average.

4. The apparatus of claim 1, wherein the processing circuitry is to encode the beam report for transmission to the gNB in response to Downlink Control Information (DCI) received from the gNB over a Physical Downlink Control Channel (PDCCH).

5. The apparatus of claim 1, wherein the processing circuitry is to calculate an average of a number N of RSRPs reported by the beam, wherein the number N is received from the gNB.

6. The apparatus of claim 1, wherein the processing circuitry is to calculate an average of a plurality of RSRPs of the beam reports from CSI-RSs received in different time slots.

7. A computer-readable storage medium comprising instructions that cause a processing circuit of a User Equipment (UE), when executed by the processing circuit, to:

measuring Reference Signal Received Power (RSRP) of one or more channel state information reference signals (CSI-RSs), wherein the CSI-RSs are transmitted via different directional beams from a next generation evolved node B (gNB);

for a particular directional beam, calculating an average of a plurality of RSRPs of the CSI-RSs associated with the particular beam received at different times; and the number of the first and second electrodes,

encoding a beam report for transmission to the gNB, the beam report comprising the average RSRP of one or more CSI-RSs associated with one or more beams.

8. The medium of claim 7, further comprising instructions to periodically encode the beam report for transmission to the gNB according to a reporting period.

9. The medium of claim 8, further comprising instructions for applying a sliding window to calculate an average when the reporting period is less than a beam measurement period required to calculate an average.

10. The medium of claim 7, further comprising instructions to encode the beam report for transmission to the gNB in response to Downlink Control Information (DCI) received from the gNB over a Physical Downlink Control Channel (PDCCH).

11. The medium of claim 7, further comprising instructions to calculate an average of a number N RSRP of the beam reports, wherein the number N is received from the gNB.

12. The medium of claim 7, further comprising instructions to calculate an average of a plurality of RSRPs of the beam reports from CSI-RSs received in different time slots.

13. An apparatus for a next generation evolved node b (gnb), the apparatus comprising:

memory and processing circuitry, wherein the processing circuitry is to encode instructions for transmission to a User Equipment (UE) that instruct the UE to:

measuring Reference Signal Received Power (RSRP) of one or more channel state information reference signals (CSI-RSs), wherein the CSI-RSs are transmitted from the gNB via different directional beams;

for a particular directional beam, calculating an average of a plurality of RSRPs of the CSI-RSs associated with the particular beam received at different times; and the number of the first and second electrodes,

encoding a beam report for transmission to the gNB, the beam report comprising the average RSRP of one or more CSI-RSs associated with one or more beams.

14. The apparatus of claim 13, wherein the processing circuitry is to encode an instruction that instructs the UE to periodically encode the beam report for transmission to the gNB according to a reporting period.

15. The apparatus of claim 14, wherein the processing circuitry is to encode an instruction to instruct the UE to apply a sliding window to compute an average when the reporting period is less than a beam measurement period required to compute an average.

16. The apparatus of claim 13, wherein the processing circuitry is to encode an instruction that instructs the UE to encode the beam report for transmission to the gNB in response to Downlink Control Information (DCI) received from the gNB over a Physical Downlink Control Channel (PDCCH).

17. The apparatus of claim 13, wherein the processing circuitry is to encode an instruction that instructs the UE to calculate an average of a number N of RSRPs of the beam reports, wherein the number N is received from the gNB.

18. The apparatus of claim 13, wherein the processing circuitry is to encode an instruction that instructs the UE to calculate an average of multiple RSRPs of the beam reports from CSI-RSs received in different time slots.

Technical Field

Embodiments described herein relate generally to wireless networks and communication systems. Although some embodiments relate to cellular communication networks, including 3GPP (third generation partnership project) networks, 3GPP LTE (long term evolution) networks, 3GPP LTE-a (LTE advanced), and 3GPP fifth generation (5G) or New Radio (NR) networks, the scope of the embodiments is not limited in this respect.

Background

In Long Term Evolution (LTE) and next generation New Radio (NR) systems, mobile terminals (referred to as user equipment or UE) are connected to a cellular network via base stations (referred to as evolved node bs or enbs or next generation node bs or gnbs). In NR, the gNB utilizes multiple antennas and beamforming techniques for downlink transmission to the UE. Methods and apparatus employed by a UE to measure quality of a plurality of directional beams received from a gNB are described herein.

Drawings

Fig. 1 illustrates an example UE and a Base Station (BS) such as an eNB or a gNB, according to some embodiments.

Fig. 2 illustrates an exemplary measurement model for generating a beam report.

Detailed Description

In Long Term Evolution (LTE) and 5G systems, mobile terminals (referred to as user equipment or UE) are connected to a cellular network via a base station (BS; in LTE systems referred to as evolved node B or eNB, and in 5G or NR systems referred to as next generation evolved node B or gNB). Fig. 1 shows an example of components of a UE 1400 and a base station (e.g., eNB or gNB) 1300. The BS 1300 includes processing circuitry 1301 connected to a radio transceiver 1302 for providing an air interface. The UE 1400 includes processing circuitry 1401 connected to a radio transceiver 1402 for providing an air interface in a wireless medium. Each transceiver in the device is connected to an antenna 1055. The antennas 1055 of the device form antenna arrays, the directivity of which can be controlled by the processing circuitry. The memory and processing circuitry of the UE and/or BS may be configured to perform functions and implement aspects of various embodiments described herein.

The NR waveform is based on Orthogonal Frequency Division Multiplexing (OFDM) with a variable set of parameters, i.e., subcarrier spacing. The NR time domain structure has a 10ms radio frame divided into ten 1ms subframes. The subframe is then divided into slots consisting of 14 OFDM symbols. The duration of a slot in milliseconds depends on the parameter set.

The air interface of NR, also referred to as radio interface or Radio Access Network (RAN), has a layered protocol architecture, where peer layers of UE and gNB communicate Protocol Data Units (PDUs), which are encapsulated Service Data Units (SDUs) of the next higher layer, between each other. The top layer in the user plane is the Service Data Adaptation Protocol (SDAP), which is responsible for mapping QoS (quality of service) bearers to radio bearers according to their quality of service requirements. The next lower layers are the Packet Data Compression Protocol (PDCP) layer, which transmits and receives IP (internet protocol) packets, and the Radio Link Control (RLC) layer, which is responsible for the segmentation and retransmission processes.

The PDCP layer communicates with a Radio Link Control (RLC) layer via a radio bearer mapped with an IP packet. At a Medium Access Control (MAC) layer, a connection to an upper RLC layer passes through a logical channel, and a connection to a lower physical layer passes through a transport channel. The primary UL transport channel is an uplink shared channel (UL-SCH), and the primary DL transport channel is a downlink shared channel (DL-SCH). Another DL transport channel, the Broadcast Channel (BCH), is used by the gNB to broadcast system information. At the physical layer, the UL-SCH is associated with a Physical Uplink Shared Channel (PUSCH), the DL-SCH is associated with a Physical Downlink Shared Channel (PDSCH), and the BCH is associated with a Physical Broadcast Channel (PBCH). The control plane protocol layers are the same as the user plane protocol layers, except that the topmost layer of the control plane in the access layer between the UE and the gNB is the Radio Resource Control (RRC) layer that replaces the SDAP layer. The physical layer is referred to as layer 1 or L1. The MAC layer, RLC layer, and PDCP layer are referred to as layer 2 or L2. The RRC layer and the non-access stratum (NAS) between the UE and the core network in the control plane and the user applications in the user plane are referred to as layer 3 or L3.

To perform scheduling and other link adaptation functions, the gNB needs to know the downlink channel from the BS to the UE. LTE and NR provide reference signals that may be used by UEs to obtain downlink Channel State Information (CSI) of a transmitting cell, referred to as channel state information reference signals (CSI-RS). The UE may then feed back the CSI thus obtained to the serving cell in the form of a CSI report. A CSI-RS is transmitted on a Physical Downlink Shared Channel (PDSCH) having a configurable periodicity and spanning an entire transmission band using specific time-frequency Resource Elements (REs) of an Orthogonal Frequency Division Multiple Access (OFDMA) transmission scheme. Multiple sets of CSI-RSs may be transmitted by a cell, where each set of CSI-RSs corresponds to a different antenna port. The UE may estimate the channel using the CSI-RS and generate a CSI report that is fed back to the serving cell by multiplexing with PDSCH data or via a Physical Uplink Control Channel (PUCCH). For periodic CSI reports, the CSI reports are encoded with Forward Error Correction (FEC) such as a polar code and transmitted over the PUCCH.

NR and LTE both provide multiple antenna transmission and reception, with Multiple Input Multiple Output (MIMO) precoding and MIMO decoding performed in the baseband digital domain. However, at the mmWave frequencies used by NR (above 6Ghz, known as FR2), it is envisaged that antenna processing will be performed in the analogue or hybrid digital-analogue domain on a carrier basis. This means that downlink transmissions to different UEs located in different directions with respect to the gNB must be separated in time. Also, in the case of analog-based receiver-side beamforming, the receive beam can only be focused in one direction at a time. Beam management refers to the establishment and maintenance of appropriate beam pairs consisting of a transmitter-side beam direction and a corresponding receiver-side beam direction that together provide good connectivity.

In NR implementations, beam management refers to a set of L1/L2 procedures to acquire and maintain a set of transmission/reception points (TRPs), which may be the gnbs, and/or UE beams that may be used for Downlink (DL) and Uplink (UL) transmission/reception. Beam management includes various operations or processes such as beam determination, beam management, beam reporting, and beam scanning operations/processes. Beam determination refers to the ability of a TRP or UE to select its own transmit (Tx)/receive (Rx) beam. Beam measurement refers to the ability of a TRP or UE to measure characteristics of a received beamformed signal. Beam reporting refers to the ability of a UE to report information of beamformed signals based on beam measurements. Beam scanning refers to the operation of transmitting and/or receiving beams covering a spatial region during a time interval in a predetermined manner.

The Tx/Rx beam correspondence at the TRP holds if at least one of the following conditions is satisfied: the TRP is capable of determining a TRP Rx beam for uplink reception based on UE downlink measurements on one or more Tx beams of the TRP; and the TRP is capable of determining a TRP Tx beam for downlink transmission based on TRP uplink measurements on one or more Rx beams of the TRP. The Tx/Rx beam correspondence at the UE is true if at least one of the following is satisfied: the UE is capable of determining a UE Tx beam for uplink transmission based on UE downlink measurements on one or more Rx beams of the UE; the UE is capable of determining a UE Rx beam for downlink reception based on the indication of TRP, wherein the indication of TRP is based on uplink measurements on one or more Tx beams of the UE; and capability indication supporting the information related to the correspondence between the UE beam and the TRxP.

In some implementations, the DL beam management includes process P-1, process P-2, and process P-3. Procedure P-1 is used to enable UE measurements on different TRP Tx beams, thereby supporting selection of TRP Tx beam/UE Rx beam. For beamforming at a TRP, process P-1 typically includes intra/inter TRP Tx beam scanning from a set of different beams. For beamforming at the UE, process P-1 typically includes a UE Rx beam sweep from a set of different beams.

Procedure P-2 is used to enable UE measurements on different TRP Tx beams, possibly changing inter/intra TRP Tx beams. Process P-2 may be a special case of process P-1, where process P-2 is used for a possibly smaller set of beams for beam refinement than process P-1. Procedure P-3 is used to enable UE measurements on the same TRP Tx beam, changing UE Rx beam, if the UE uses beamforming. Process P-1, process P-2, and process P-3 may be used for aperiodic beam reporting.

UE measurements based on RS for beam management (at least CSI-RS) are made of K beams (where K is the total number of configured beams) and the UE reports the measurements of N selected Tx beams (where N may or may not be a fixed number). Procedures based on RS for mobile purposes are not excluded. If N < K, the beam information to be reported includes the measurement quantities of the N beams and information indicating the N DL Tx beams. Other information or data may be included in or with the beam information. When a UE is configured with K '>1 non-zero power (NZP) CSI-RS resources, the UE may report N' CSI-RS resource indication identities (CRI).

In some NR implementations, the UE may trigger a mechanism to recover from beam failure, referred to as "beam recovery," "beam failure recovery request procedure," or the like. A beam failure event may occur where the beam pair link quality of the associated control channel falls below a threshold, or a timeout of an associated timer occurs, etc. When a beam failure occurs, a beam recovery mechanism is triggered. The network may explicitly configure resources for the UE for UL transmission of signals for recovery purposes. The configuration of resources is supported in case the base station (e.g. TRP, gNB, etc.) listens from all or part of the direction (e.g. random access area). The UL transmissions/resources used for reporting beam failure may be located in the same time instance as the Physical Random Access Channel (PRACH) or resources orthogonal to the PRACH resources, or in a time instance different from the PRACH (configurable for the UE). Transmission of DL signals is supported for allowing the UE to monitor the beams to identify new potential beams.

For beam failure recovery, a beam failure may be indicated if one, more, or all of the serving PDCCH beams fail. If the beam fault is indicated, a beam fault recovery request process is initiated. For example, when a beam failure is detected on the serving SSB/CSI-RS, a beam failure recovery request procedure may be used to indicate to the serving gNB (or TRP) of the new SSB or CSI-RS. The beam failure may be detected by lower layers and indicated to a Medium Access Control (MAC) entity of the UE.

In some implementations, beam management includes providing or not providing beam related indications. As providing the beam-related indication, information related to UE-side beamforming/reception procedures for CSI-RS based measurements may be indicated to the UE through the QCL. The control channel and the corresponding data channel may be supported for transmission using the same or different beams.

The Downlink (DL) beam indication is based on a Transmission Configuration Indication (TCI) status. The TCI status is indicated in a TCI list configured by a Radio Resource Control (RRC) and/or Medium Access Control (MAC) Control Element (CE). In some implementations, a UE may be configured by higher layer signaling to a maximum of M TCI-States to decode PDSCH, depending on detected PDCCH with Downlink Control Information (DCI) for the UE and a given serving cell, where M depends on UE capability. Each configured TCI state includes a set of Reference Signals (RS) TCI-RS-SetConfig. Each TCI-RS-SetConfig includes parameters for configuring a quasi-co-location relationship between RSs in the RS group and a demodulation reference signal (DM-RS) port group of the PDSCH. The RS group includes a reference to one or two DL RSs and an associated QCL-type configured by a higher layer parameter quasi co-located type (QCL-type) for each DL RS. For the case of two DL RSs, the QCL type should not be the same whether the reference is for the same DL RS or for different DL RSs. The quasi co-located type indicated to the UE is based on a higher layer parameter, QCL-type, and employs one or a combination of the following types: QCL-type A: { doppler shift, doppler spread, mean delay, delay spread }; QCL-type B: { doppler shift, doppler spread }; QCL-type C: { mean delay, doppler shift }; QCL-type D: { space Rx parameters }.

The UE may receive a selection command (e.g., in the MAC CE) for mapping up to 8 TCI States to code points of the DCI field TCI-States. Until the UE receives the higher layer configuration of the TCI state and before receiving the activation command, the UE may assume that the antenna ports of one DM-RS port group of the PDSCH of the serving cell are spatially quasi co-located with the SSBs determined in the initial access procedure. The DCI field TCI-States directly indicates TCI status when the number of TCI statuses in TCI-States is less than or equal to 8.

The beam failure recovery request may be delivered over dedicated PRACH or Physical Uplink Control Channel (PUCCH) resources. For example, for a serving cell, a UE may be configured by a higher layer parameter Beam-Failure-Detection-RS-ResourceConfig to have a set of periodic CSI-RS resource configuration indicesAnd configured by a higher layer parameter Candidate-Beam-RS-List to have a set of CSI-RS resource configuration indices and/or SS/PBCH block indicesFor radio link quality measurements of the serving cell. If there is no configuration, beam failure detection may be based on CSI-RS or SSB spatially quasi co-located with a PDCCH demodulation reference Signal (DMRS) (QCLed). For example, if the UE is not set with the higher layer parameter Beam-Failure-Detection-RS-ResourceConfig, the UE determines thatIncluding an SS/PBCH block and a periodic CSI-RS configuration having a value of a higher layer parameter TCI-StatesPDCCH that is the same as a value of a control resource set (CORESET) that the UE is configured to use for monitoring the PDCCH.

Physical layer of the UE is based on the relative threshold Q_out,LRResource configuration set ofTo evaluate the radio link quality. Threshold Q_out,LRCorresponding to the default values of the higher layer parameters RLM-IS-OOS-threshold _ Config and Beam-failure-candidate-Beam-threshold, respectively. For collectionsThe UE evaluates the radio link quality only according to the quasi co-located periodic CSI-RS resource configuration or SS/PBCH block, where the DM-RS of the PDCCH reception DM-RS is monitored by the UE. Q to be configured by the UE_in,LRThe threshold is applied to the periodic CSI-RS resource configuration. UE is scaling SS/PBCH block transmission with the value provided by higher layer parameter Pc _ SSAfter power transmission, Q_out,LRThe threshold is applied to the SS/PBCH block.

In some implementations, if the MAC entity receives a beam failure indication from a lower layer, the MAC entity starts a beam failure recovery timer (beamfailure recovery timer) and initiates a random access procedure. If the beamFailureRecoveryTimer times out, the MAC entity indicates to the upper layer that the beam failure recovery request failed. If a DL assignment or UL grant is received (e.g., on PDCCH addressed for cell radio network temporary identifier (C-RNTI)), the MAC entity may stop and reset the beamfailure recoverytimer and consider the successful completion of the beam failure recovery request procedure.

In some embodiments, the UE measures one or more beams of the cell (e.g., in RRC _ CONNECTED mode) and calculates an average of the measurements (power values) to derive the cell quality. The UE may be configured to consider a subset of the detection beams, such as the N best beams above an absolute threshold. Filtering occurs at two different levels, including at the physical layer (PHY) to derive beam quality and at the RRC level to derive cell quality from multiple beams. The cell quality from beam measurements can be derived in the same way by the serving cell and the non-serving cell. If the gNB configures the UE to do so, the measurement report contains the measurements for the X best beams. For channel state estimation purposes, the UE may be configured to measure CSI-RS resources and estimate the downlink channel state based on CSI-RS measurements. The UE feeds back the estimated channel state to the gNB for link adaptation.

Fig. 2 shows an exemplary measurement model. In fig. 2, point a includes measurements (e.g., beam-specific samples) internal to the PHY. The layer 1(L1) filtering includes an internal layer 1 filtering circuit for filtering the input measured at point a. The exact filtering mechanism and how the measurements are actually performed at the PHY may be a particular implementation. Measurements (e.g., beam specific measurements) are reported by L1 filtering to point a¹Layer 3(L3) beam filtering circuitry and beam consolidation/selection circuitry.

The beam consolidation/selection circuitry including consolidated beam specific measurements to derive cell qualityAn electrical circuit. For example, if N>Otherwise when N is 1, the best beam measurement can be selected to derive the cell quality. The configuration of the beams is provided by RRC signaling. The measurements derived from the beam specific measurements (e.g., cell quality) are then reported to L3 filtering for the cell quality circuit after beam consolidation/selection. In some embodiments, the reporting period at point B may be equal to point a¹One measurement cycle of (a).

The L3 filtering for the cell quality circuit is configured to filter the measurements provided at point B. The configuration of the layer 3 filter is provided by the aforementioned RRC signaling or by different/separate RRC signaling. In some embodiments, the filtered reporting period at point C may be equal to one measurement period at point B. The measurements are provided to the evaluation of the reporting criteria circuit at point C after processing in the layer 3 filter circuit. In some embodiments, the reporting rate may be the same as the reporting rate at point B. The measurement input may be used to report one or more evaluations of the criteria.

The evaluation of the reporting criteria circuit is configured to check whether an actual measurement report is required at point D. The evaluation may be based on more than one measurement flow at reference point C. In one example, the evaluation may involve a comparison between different measurements, such as the measurement provided at point C and point C¹And the other measurement provided. In some embodiments, the UE may at least every time at point C, at point C¹And evaluating the reporting criteria when reporting new measurements. The reporting criteria configuration is provided by the RRC signaling described above (UE measurements) or by a different/separate RRC signaling. After evaluation, the measurement report information is sent (e.g. as a message) on the radio interface at point D.

Refer back to point A¹Will be at point A¹The measurements provided at (a) are provided to an L3 beam filtering circuit configured to perform beam filtering of the provided measurements (e.g., beam-specific measurements). The configuration of the beam filter is provided by the RRC signaling described above or by different/separate RRC signaling. In some embodiments, the filtered reporting period at point E may be equal to point a¹One measurement cycle of (a). The K beams may correspond to new radios(NR) measurements on Synchronization Signal (SS) blocks (SSBs) or channel state information reference signal (CSI-RS) resources configured for L3 mobility for the gNB and detected by the UE at L1.

After processing in the beam filter measurements (e.g., beam specific measurements), the measurements are provided to a beam selection for a reporting circuit at point E. This measurement is used as an input to select the X measurements to be reported. In some embodiments, the reporting rate may be comparable to point a¹The reporting rate is the same. The beam selection for the beam reporting circuitry is configured to select X measurements from the measurements provided at point E. The configuration of this module is provided by the aforementioned RRC signaling or by different/separate RRC signaling. The beam measurement information included in the measurement report is sent or scheduled for transmission on the radio interface at point F.

The measurement report comprises a measurement identity of the relevant measurement configuration triggering the reporting. The measurement report may also include cell and beam measurements included in the measurement report that are configured by the network (e.g., using RRC signaling). The measurement report may also include the number of non-serving cells to report, which may be limited by network configuration. Cells belonging to a blacklist configured by the network are not used for event evaluation and reporting. In contrast, when the network configures the white list, only cells belonging to the white list are used for event evaluation and reporting. The beam measurements comprised in the measurement report are configured by the network and such measurement report comprises or indicates only the beam identifier, either the measurement result and the beam identifier or no beam report.

For NR systems, the current measurement period for beam reporting is not clear. Embodiments herein provide a measurement period of periodic CSI-RS based L1-RSRP and aperiodic CSI-RS based L1-RSRP for beam reporting. According to various embodiments, for periodic CSI-RS based L1-RSRP, there are two options for the measurement period:

-option 1: time domain averaging of L1-RSRP measurements is not performed at the UE side;

-option 2: assume that L1 is equally divided by X samples.

For option 1, assume that the UE will apply beam reporting on a single slot basis and leave the gNB to perform measurement averaging. However, there are some drawbacks to reporting based on a single slot. If there are multiple Tx beams, e.g., 16/32 beams, and the UE is requested to report a maximum of 4 beams, the UE will select 4 beams based on only a single slot measurement. If the single slot measurement accuracy is not good enough, the correct beam may not be selected. Simulation results based on single samples have shown that the measurement accuracy is in some cases poor and the correct beam cannot be selected.

Simulation results have shown that the measurement accuracy depends on CSI-RS density, bandwidth, channel model and subcarrier spacing. For a single sample, in some cases, the measurement accuracy is not good even if the SNR is 0 dB. For example, for the ETU channel model, the single sample accuracy may be greater than 2.5dB, where the ETU channel occupies 24 RBs if D1/3 and 96 RBs if D1. At 90% the L1-RSRP with an accuracy of ± 2.5dB can only guarantee that the reported beams can be within the best 5/8/12 beams out of the total 8/16/32 beams, respectively. The accuracy requirements will be more stringent if better beam reporting quality is required.

The reported beam will change for different reporting times and it is difficult for the gNB to calculate an average of the measurements. For some beams there may be only one reported result for which an average cannot be calculated. The delay may be large if the gNB is to wait a period of time to obtain the results of multiple beams. Therefore, for the UE side, it is better to compute the average to help improve the report quality.

If the CSI-RS beam reporting interval and the beam measurement period are the same, there must be enough samples for calculating the average value during the measurement period. However, if the CSI-RS beam reporting interval is less than the beam measurement period, there may not be enough samples for calculating the average. In these cases, a sliding window may be applied for calculating the sample average.

For aperiodic CSI-RS based L1-RSRP, if a single sample measurement is applied, the UE may receive DCI at time n and the UE will issue a beam report at time n + M, where M is the measurement delay of a single sample. However, since a single sample measurement does not provide sufficient accuracy, an average of multiple samples needs to be calculated. Assume that an average of X samples needs to be calculated. The gNB may send out the candidate Tx beam X times after it sends out the DCI. The UE will only send a beam report when it finishes averaging X samples. If the UE receives DCI at time n, the UE will send out a beam report at time n + P, where P is the measurement delay averaged over multiple samples. The reporting delay may be extended for the case of calculating an average of multiple samples, as compared to the case of a single sample.

In embodiment 1, an apparatus for a User Equipment (UE) comprises: a memory and a processing circuit, wherein the processing circuit is to: measuring Reference Signal Received Power (RSRP) of one or more channel state information reference signals (CSI-RSs), wherein the CSI-RSs are transmitted from a next generation evolved node B (gNB) via different directional beams; for a particular directional beam, calculating an average of a plurality of RSRPs of CSI-RSs associated with the particular beam received at different times; and encoding a beam report for transmission to the gNB, the beam report comprising an average RSRP of one or more CSI-RSs associated with the one or more beams.

The processing circuitry may be operative to periodically encode beam reports for transmission to the gNB according to a reporting period, where the reporting period may be specified by the gNB. The processing circuitry may be operative to apply a sliding window to the calculated average when the reporting period is less than the beam measurement period required to calculate the average. The processing circuitry may be configured to encode a beam report for transmission to the gNB in response to Downlink Control Information (DCI) received from the gNB over a Physical Downlink Control Channel (PDCCH). The processing circuitry may be operative to calculate an average of a number N of RSRPs reported by the beams, where the number N is received from the gNB. The processing circuitry may be to calculate an average of a plurality of RSRPs from beam reports of CSI-RSs received in different time slots.

In embodiment 2, an apparatus for a next generation evolved node b (gnb), the apparatus comprising: memory and processing circuitry, wherein the processing circuitry is to encode instructions for transmission to a User Equipment (UE) that instruct the UE to: measuring Reference Signal Received Power (RSRP) of one or more channel state information reference signals (CSI-RSs), wherein the CSI-RSs are transmitted from the gNB via different directional beams; for a particular directional beam, calculating an average of a plurality of RSRPs of CSI-RSs associated with the particular beam received at different times; and encoding a beam report for transmission to the gNB, the beam report comprising an average RSRP of one or more CSI-RSs associated with the one or more beams. The processing circuitry may be configured to encode an instruction instructing the UE to periodically encode beam reports for transmission to the gNB according to a reporting period. The processing circuitry may be operative to encode an instruction instructing the UE to apply a sliding window to calculate the average value when the reporting period is less than a beam measurement period required to calculate the average value. The processing circuitry may be configured to encode an instruction instructing the UE to encode a beam report for transmission to the gNB in response to Downlink Control Information (DCI) received from the gNB over a Physical Downlink Control Channel (PDCCH). The processing circuitry may be to encode an instruction instructing the UE to calculate an average of a number N of RSRPs reported by the beam, where the number N is received from the gNB. The processing circuitry may be to encode an instruction instructing the UE to calculate an average of a plurality of RSRPs of beam reports from CSI-RSs received in different time slots.

In embodiment 3, a non-transitory computer readable storage medium includes instructions to cause processing circuitry or a gNB of a UE, when executed by the processing circuitry, to perform any of the functions described in embodiments 1 and 2.

The above detailed description refers to the accompanying drawings. The same reference numbers may be used in different drawings to identify the same or similar elements. In the description above, for purposes of explanation and not limitation, specific details are set forth such as particular structures, architectures, interfaces, techniques, etc. in order to provide a thorough understanding of the various aspects of the embodiments. However, it will be apparent to one having ordinary skill in the art having had the benefit of the present disclosure that the various aspects of the embodiments may be practiced in other examples that depart from these specific details. In certain instances, descriptions of well-known devices, circuits, and methods are omitted so as not to obscure the description of the various embodiments with unnecessary detail. For purposes of this document, the phrase "a or B" refers to (a), (B), or (a and B).

The embodiments described above may be implemented in various hardware configurations, which may include a processor for executing instructions that perform the described techniques. Such instructions may be embodied in a machine-readable medium, such as a suitable storage medium or memory or other processor-executable medium.

The above description is intended to be illustrative, and not restrictive. For example, the above-described examples (or one or more aspects thereof) may be used in combination with each other. Other embodiments may be used, such as by one of ordinary skill in the art upon reviewing the above description. The abstract of the specification allows the reader to quickly ascertain the nature of the technical disclosure. This Abstract is provided with the understanding that the technical disclosure will not be used to interpret or limit the scope or meaning of the claims. Furthermore, in the above detailed description, various features may be grouped together to simplify the present disclosure. However, the claims may not set forth every feature disclosed herein as embodiments may feature subsets of such features. Moreover, embodiments may include fewer features than those disclosed in the particular examples. Thus, the following claims are hereby incorporated into the detailed description, with claims standing on their own as separate embodiments.