WO2022236530A1

WO2022236530A1 - Methods and apparatuses for beam failure recovery

Info

Publication number: WO2022236530A1
Application number: PCT/CN2021/092602
Authority: WO
Inventors: Wei Ling; Chenxi Zhu; Bingchao LIU; Yi Zhang; Lingling Xiao
Original assignee: Lenovo (Beijing) Limited
Priority date: 2021-05-10
Filing date: 2021-05-10
Publication date: 2022-11-17

Abstract

Embodiments of the present application are related to a method and apparatus for beam failure recovery. An exemplary method includes: receiving configuration information at least indicating: two failure detection resource sets; and two sounding reference signal (SRS) resource sets for physical uplink shared channel (PUSCH) transmission, wherein the two SRS resource sets are one to one associated with the two failure detection resource sets; and transmitting a medium access control (MAC) control element (CE) corresponding to that a radio link quality of all failure detection resources in one of the two failure detection resource sets is lower than a threshold, in a PUSCH transmission occasion being associated with a SRS resource set associated with the other of the two failure detection resource sets.

Description

METHODS AND APPARATUSES FOR BEAM FAILURE RECOVERY

TECHNICAL FIELD

Embodiments of the present application generally relate to wireless communication technology, and in particular to a method and an apparatus for beam failure recovery (BFR) , e.g., in multiple transmit-receive points (TRPs) .

BACKGROUND

Multi-TRP/panel transmission has been introduced into new radio (NR) since Release 16 (R16) , and enhancements on multiple-input multiple-output (MIMO) for NR have been discussed, for example in RP-182067. During multi-TRP transmission, two or more TRPs (or panels) may be used to transmit data to a user equipment (UE) to improve reliability and robustness. A work item description (WID) approved on multiple-input multiple-output (MIMO) in NR Release 17 (R17) includes a research topic, evaluating and; if needed, specifying beam-management-related enhancements for simultaneous multi-TRP transmission with multi-panel reception. A beam can be represented by "spatial relation information" etc.

It is agreed that TRP-specific BFR is to be supported in R17, which is designed based on R16 secondary cell (SCell) BFR scheme. According to the latest agreements, up to two dedicated physical uplink control channel (PUCCH) scheduling request (SR) (PUCCH-SR) resources can be configured for TRP-specific BFR in a UE, wherein each TRP can be associated with a PUCCH-SR to trigger a physical uplink shared channel (PUSCH) for carrying a medium access control (MAC) control element (CE) of TRP-specific BFR when the TRP is failed, and the MAC CE of TRP-specific BFR is for reporting the beam failure of the failed TRP and the corresponding new beam index if any. However, UEs may not be aware to which TRP the PUSCH is transmitted, and may transmit the MAC CE of TRP-specific BFR of the failed TRP in a PUSCH transmission to the failed TRP itself. In this case, the MAC CE cannot be received successfully, which will increase the latency of TRP beam failure recovery and decrease the whole throughput of a multi-TRP communication system.

Given the above, it is desirable to improve technology for beam failure recovery, especially in multi-TRP transmission.

SUMMARY OF THE APPLICATION

One objective of the present application is to provide a technical solution for beam failure recovery, which can facilitate the beam management, e.g., in multi-TRP transmission.

According to some embodiments of the present application, a method may include: receiving configuration information at least indicating: two failure detection resource sets; and two sounding reference signal (SRS) resource sets for PUSCH transmission, wherein the two SRS resource sets are one to one associated with the two failure detection resource sets; and transmitting a MAC CE corresponding to that a radio link quality of all failure detection resources in one of the two failure detection resource sets is lower than a threshold, in a PUSCH transmission occasion being associated with a SRS resource set associated with the other of the two failure detection resource sets.

According to some other embodiments of the present application, a method may include: transmitting configuration information at least indicating: two failure detection resource sets; and two SRS resource sets for PUSCH transmission, wherein the two SRS resource sets are one to one associated with the two failure detection resource sets; and receiving a MAC CE corresponding to that a radio link quality of all failure detection resources in one of the two failure detection resource sets is lower than a threshold, in a PUSCH transmission occasion being associated with a SRS resource set associated with the other of the two failure detection resource sets.

In some embodiments of the present application, the PUSCH transmission occasion is indicated to be associated with the SRS resource set associated with the other of the two failure detection resource sets via a downlink control information (DCI) scheduling or activating the PUSCH transmission occasion.

In some other embodiments of the present application, the PUSCH transmission occasion is configured to be associated with the SRS resource set associated with the other of the two failure detection resource sets by radio resource control (RRC) signaling.

In some yet other embodiments of the present application, the configuration information further indicates two CORESETGroupIndex values for control resource sets (CORESETs) , wherein the two CORESETGroupIndex values are one to one associated with the two SRS resource sets and the two failure detection resource sets, and the PUSCH transmission occasion is configured to be associated with a CORESETGroupIndex value associated with the other of the two failure detection resource sets.

In some yet other embodiments of the present application, the configuration information further indicates two CORESETPoolIndex values for CORESETs, wherein the two CORESETPoolIndex values are one to one associated with the two SRS resource sets and the two failure detection resource sets. In the case that the PUSCH transmission occasion is scheduled or activated by a DCI, the DCI is received in a CORESET with a CORESETPoolIndex value associated with the other of the two failure detection resource sets. The PUSCH transmission occasion is configured to be associated with a CORESETPoolIndex value or a SRS resource set associated with the other of the two failure detection resource sets by RRC signaling.

Some embodiments of the present application also provide an apparatus, which include: at least one non-transitory computer-readable medium having computer executable instructions stored therein; at least one receiving circuitry; at least one transmitting circuitry; and at least one processor coupled to the at least one non-transitory computer-readable medium, the at least one receiving circuitry and the at least one transmitting circuitry. The computer executable instructions are programmed to implement any method as stated above with the at least one receiving circuitry, the at least one transmitting circuitry and the at least one processor.

Embodiments of the present application at least provide a technical solution for beam failure recovery in multi-TRP transmission, which can reduce the latency of TRP beam failure recovery and increase the whole throughput of a multi-TRP communication system, and will further facilitate the deployment and implementation of the NR.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to describe the manner in which advantages and features of the application can be obtained, a description of the application is rendered by reference to specific embodiments thereof, which are illustrated in the appended drawings. These drawings depict only example embodiments of the application and are not therefore to be considered limiting of its scope.

FIG. 1 is a schematic diagram illustrating an exemplary wireless communication system according to some embodiments of the present application;

FIG. 2 is a flow chart illustrating a method for beam failure recovery in multi-TRP transmission according to some embodiments of the present application;

FIG. 3 illustrates an exemplary diagram of MAC CE of TRP-specific BFR transmission in Scenario 1 according to some embodiments of the present application;

FIG. 4 illustrates an exemplary diagram of MAC CE of TRP-specific BFR transmission in Scenario 2 according to some embodiments of the present application; and

FIG. 5 illustrates a simplified block diagram of an apparatus for beam failure recovery in multi-TRP transmission according to some embodiments of the present application.

DETAILED DESCRIPTION

The detailed description of the appended drawings is intended as a description of the preferred embodiments of the present application and is not intended to represent the only form in which the present application may be practiced. It should be understood that the same or equivalent functions may be accomplished by different embodiments that are intended to be encompassed within the spirit and scope of the present application.

Reference will now be made in detail to some embodiments of the present application, examples of which are illustrated in the accompanying drawings. To facilitate understanding, embodiments are provided under specific network architecture and new service scenarios, such as the 3rd generation partnership project (3GPP) 5G (NR) , 3GPP long-term evolution (LTE) Release 8, and so on. It is contemplated that along with the developments of network architectures and new service scenarios, all embodiments in the present application are also applicable to similar technical problems; and moreover, the terminologies recited in the present application may change, which should not affect the principle of the present application.

A wireless communication system generally includes one or more base stations (BSs) and one or more UEs. Furthermore, a BS may be configured with one TRP (or panel) or more TRPs (or panels) . A TRP can act like a small BS. The TRPs can communicate with each other by a backhaul link. Such backhaul link may be an ideal backhaul link or a non-ideal backhaul link. Latency of the ideal backhaul link may be deemed as zero, and latency of the non-ideal backhaul link may be tens of milliseconds and much larger, e.g. on the order of tens of milliseconds, than that of the ideal backhaul link.

In a wireless communication system, a single TRP can be used to serve one or more UEs under the control of a BS. In different scenarios, a TRP may be referred to as different terms. Persons skilled in the art should understand that as 3GPP and the communication technology develop, the terminologies recited in the specification may change, which should not affect the scope of the present application. It should be understood that the TRP (s) (or panel (s) ) configured for the BS may be transparent to a UE.

FIG. 1 is a schematic diagram illustrating an exemplary wireless communication system 100 according to some embodiments of the present application.

Referring to FIG. 1, a wireless communication system 100 can include a base station (BS) 101, TRPs 103 (e.g., a TRP 103a and a TRP 103b) , and UEs 105 (e.g., a UE 105a, a UE 105b, and a UE 105c) . Although only one base station 101, two TRPs 103 and three UEs 105 are shown for simplicity, it should be noted that the wireless communication system 100 may include more or less communication device (s) or apparatus in accordance with some other embodiments of the present application.

In some embodiments of the present application, a BS 101 may be referred to as an access point, an access terminal, a base, a base unit, a macro cell, a Node-B, an evolved Node B (eNB) , a gNB, an ng-eNB, a Home Node-B, a relay node, or a device, or described using other terminology used in the art. The UEs 105 (for example, the UE 105a, the UE 105b, and the UE 105c) may include, for example, but is not limited to, a computing device, a wearable device, a mobile device, an IoT device, a vehicle, etc.

The TRPs 103, for example, the TRP 103a and the TRP 103b can communicate with the base station 101 via, for example, a backhaul link. Each of TRPs 103 can serve some or all of UEs 105. As shown in FIG. 1, the TRP 103a can serve some mobile stations (which include the UE 105a, the UE 105b, and the UE 105c) within a serving area or region (e.g., a cell or a cell sector) . The TRP 103b can serve some mobile stations (which include the UE 105a, the UE 105b, and the UE 105c) within a serving area or region (e.g., a cell or a cell sector) . The TRP 103a and the TRP 103b can communicate to each other via, for example, a backhaul link.

The multi-TRP transmission may refer to at least two TRPs (or panels) to transmit data to a UE. As shown in FIG. 1, for the same UE 105 (e.g., the UE 105a, the UE 105b, or the UE 105c) , two TRPs (e.g., the TRP 103a and the TRP 103b) may both transmit data to it, which is an exemplary scenario of the multi-TRP transmission.

In addition, in R15, a random access channel (RACH) -based BFR is defined for primary cell (PCell) , and in R16, a MAC CE-based BFR is defined for SCell. However, both the BFRs for PCell and SCell are only defined in single-TRP transmission. Thus, for multiple-TRP transmission, the beam failure recovery should be reconsidered.

For multi-TRP transmission, the beam failure recovery can be performed for each TRP, respectively. In order to detect the beam condition per TRP, separate beam failure detection (BFD) reference signals (RSs) may be configured for each TRP in the multiple-TRP transmission. Similar to the BFD RSs, separate new candidate beams can also be configured for each TRP in the multiple-TRP transmission. When a beam failure is detected for a TRP, the beam failure information as well as new candidate beam information associated with the failed TRP may be transmitted to the network via a MAC CE of BFR in a PUSCH. Since the MAC CE of BFR can be transmitted in a PUSCH which is not triggered by a PUCCH-SR resource configured for BFR, it is highly possible that a MAC CE of BFR of a failed TRP can be transmitted in a PUSCH transmission (or PUSCH) which is not triggered by a PUCCH-SR resource associated with the failed TRP. When the PUSCH carrying the MAC CE of BFR is transmitted to the failed TRP, the MAC CE cannot be received successfully in the network side. That will increase the latency of TRP beam failure recovery and decrease the performance of multi-TRP communication system. Therefore, it should ensure that the PUSCH carrying the MAC CE of BFR will be successfully transmitted, e.g., not being transmitted to the failed TRP.

Embodiments of the present application provide solutions for beam failure recovery, which can at least solve the above technical problems, thereby improving the beam management in the multi-TRP transmission. For example, embodiments of the present application disclose how to transmit a MAC CE in a PUSCH transmission occasion, which corresponds to all beams in a failure detection RS set failed in the case that two failure detection RS sets are configured TRP-specific BFR and two SRS resource sets are configured for PUSCH transmission. There is a one to one association between each failure detection RS set and each SRS resource set, and each PUSCH transmission is indicated to be associated with a SRS resource set of two SRS resource sets by RRC signaling or DCI. Therefore, each PUSCH transmission occasion is associated with a failure detection RS set, and the PUSCH transmission occasion for carrying a MAC CE corresponding to all beams in a failure detection RS set failed is associated with the other one of the two failure detection RS sets.

More details on embodiments of the present application will be illustrated in the following text in combination with the appended drawings.

FIG. 2 is a flow chart illustrating a method for beam failure recovery in multi-TRP transmission according to some embodiments of the present application. Although the method is illustrated in a system level by a network side, e.g., a BS 101 and a remote side, e.g., a UE 105, persons skilled in the art can understand that the method implemented in the UE and that implemented in the BS can be separately implemented and incorporated by other apparatus with the like functions.

As shown in FIG. 2, in step 201, the network side, e.g., the BS 101 as illustrated and shown in FIG. 1 may transmit configuration information to the remote side, e.g., the UE 105 as illustrated and shown in FIG. 1.

According to some embodiments of the present application, the configuration information may at least indicate: two failure detection resource sets, and two SRS resource sets for PUSCH transmission. The two SRS resource sets are one to one associated with the two failure detection resource sets. For example, a first SRS resource set is associated with a first failure detection resource set and a second SRS resource set is associated with a second failure detection resource set. In some other embodiments of the present application, the configuration information may include more than two failure detection resource sets and more than two SRS resource sets for PUSCH transmission.

According to current agreements, each TRP is configured with a failure detection resource set, e.g., a BFD-RS set per-TRP in R17, which may be changed or updated as the evolution of 3GPP specifications or other related specifications/protocols. Therefore, different failure detection resource set indexes can be used to distinguish different TRPs. In some embodiments of the present application, each failure detection resource set may be configured by a RRC signaling. For example, each failure detection resource set may be a set of periodic channel state information-reference signal (CSI-RS) resource configuration indexes configured by the RRC signaling. When there is no failure detection resource set configured by the RRC signaling, the UE may determine each failure detection resource set to include periodic CSI-RS resource configuration indexes with the same values as the RS indexes in the RS sets indicated by a transmission configuration indicator (TCI) state for respective control resource sets (CORESETs) with the same value of CORESETPoolIndex or CORESETGroupIndex when two CORESETPoolIndex values or two CORESETGroupIndex values are configured for CORSETs that the UE uses for monitoring physical downlink control channel (PDCCH) . When there are two RS indexes in a TCI state, each failure detection resource set may include RS indexes with quasi co-location (QCL) -TypeD configuration for the corresponding TCI state.

According to some embodiments of the present application, each SRS resource set of the two SRS resource sets for PUSCH transmission (or PUSCH) is associated with one TRP or one beam. Both the two SRS resource sets are configured with the same PUSCH transmission scheme, e.g., both with usage as "codebook" or "non-codebook. " The two PUSCH transmission schemes are supported according to TS 38.214 in R15/R16, and they may be changed or updated as the evolution of 3GPP specifications or other related specifications/protocols.

The PUSCH transmission can be configured or indicated as "repeated" or "not repeated. " When a PUSCH transmission is transmitted one shot (that is, there is no repetition) or it is transmitted with a single beam, it can be indicated with which SRS resource set the PUSCH transmission is associated. However, a PUSCH transmission with repetitions by using multiple beams is also supported in R17. Two SRS resource sets can be configured to be associated with the PUSCH transmission with repetitions. In this case, a beam mapping pattern will be configured for a PUSCH with repetition by using multiple beams, wherein each repetition of a PUSCH transmission with repetitions by using multiple beams is associated with one SRS resource set. The beam mapping pattern can be that according to R16 ultra-reliable and low latency communications (URLLC) PDSCH Scheme 4, e.g., the cyclical mapping pattern, or the sequential mapping pattern. The mapping pattern for the SRS resource sets and the plurality of PUSCH repetitions (or PUSCH transmission repetitions) can be any mapping pattern, which is similar to a beam mapping pattern, e.g., the cyclical mapping pattern, or the sequential mapping pattern.

In the remote side, e.g., the UE 105 will receive configuration information from the network side in step 202. The received configuration information are the same as that configured in the network side, e.g., at least indicating: two failure detection resource sets, and two SRS resource sets for PUSCH transmission, wherein the two SRS resource sets are one to one associated with the two failure detection resource sets by a predefined rule or RRC signaling.

After receiving the configuration information, the UE 105 may access the radio link quality of each failure detection resource set associated with a TRP. In the case that the radio link quality of all failure detection resources in a failure detection resource set is lower than a threshold (e.g., all beams in the failure detection resource set failed or a beam failure for the corresponding TRP is detected) , the TRP associated with the failure detection resource set is deemed as "failed. " The threshold is a predefined or configured threshold, e.g., a RRC configured threshold. The UE will prepare a MAC CE corresponding to that a radio link quality of all failure detection resources in one of the two failure detection resource sets is lower than a threshold, which is also referred to as a MAC CE of TRP-specific BFR in some embodiments of the present application. The UE will also try to find a new beam for the failed TRP. Accordingly, besides reporting the beam failure of the failed TRP, the MAC CE of TRP-specific BFR may also report the corresponding new beam if it is found.

In step 204, the UE may transmit the MAC CE of TRP-specific BFR in a PUSCH transmission occasion being associated with a SRS resource set associated with the other of the two failure detection resource sets. That is, the MAC CE of TRP-specific BFR of the failed TRP will not be transmitted to the failed TRP itself. Accordingly, the success probability of receiving the MAC CE of TRP-specific BFR of the failed TRP in the network will be greatly increased. In some embodiments of the present application, only in the case that the other of the two failure detection resource sets is deemed as not failed, that is, the other TRP is deemed as not failed, the MAC CE of TRP-specific BFR of the failed TRP will be transmitted to the other TRP by the UE.

Similarly, in the network side, in step 205, the MAC CE of TRP-specific BFR of the failed TRP, that is, the MAC CE corresponding to that a radio link quality of all failure detection resources in one of the two failure detection resource sets is lower than a threshold, will be received in a PUSCH transmission occasion being associated with a SRS resource set associated with the other of the two failure detection resource sets.

Herein, a PUSCH transmission occasion is defined as a PUSCH transmission without repetition, or a repetition of a PUSCH transmission with repetition by using one beam, or a repetition of a PUSCH transmission with repetition by using multiple beams. Each PUSCH transmission occasion can be associated with a SRS resource set of the two SRS resource sets in various manners, e.g., being configured by RRC signaling or indicated by DCI. Since each SRS resource set is one to one associated with a failure detection resource set and a PUSCH transmission occasion can be indicated to be associated with a SRS resource set, a PUSCH transmission occasion can also be associated with a failure detection resource set.

Specifically, in some embodiments of the present application, a PUSCH transmission occasion for carrying the MAC CE is indicated to be associated with a SRS resource set via a DCI scheduling or activating the PUSCH transmission occasion when it is scheduled or activated by the DCI. Herein (through the specification) , a DCI means DCI in a PDCCH (or PDCCH transmission) . For example, the PUSCH transmission occasion for carrying the MAC CE of TRP-specific BFR of a failed TRP is indicated to be associated with the SRS resource set associated with the other of the two failure detection resource sets via a DCI scheduling or activating the PUSCH transmission occasion.

In some other embodiments of the present application, a configured grant PUSCH transmission occasion for carrying the MAC CE is indicated to be associated with a SRS resource set via RRC signaling. For example, the PUSCH transmission occasion for carrying the MAC CE of TRP-specific BFR of a failed TRP is configured to be associated with the SRS resource set associated with the other of the two failure detection resource sets by RRC signaling.

In some yet other embodiments of the present application, the configuration information further indicates two CORESETGroupIndex values for CORESETs, wherein the two CORESETGroupIndex values are one to one associated with the two SRS resource sets and the two failure detection resource sets. A configured grant PUSCH transmission occasion for carrying the MAC CE is indicated to be associated with a SRS resource set or a CORESETGroupIndex value by RRC signaling, and then will be associated with a failure detection resource set. For example, the configured grant PUSCH transmission occasion for carrying the MAC CE of TRP-specific BFR of a failed TRP is configured to be associated with a CORESETGroupIndex value associated with the other of the two failure detection resource sets.

In some yet other embodiments of the present application, the configuration information may further indicate two CORESETPoolIndex values for CORESETs, wherein the two CORESETPoolIndex values are one to one associated with the two SRS resource sets and the two failure detection resource sets. A PUSCH transmission occasion for carrying the MAC CE is indicated to be associated with a SRS resource set or a CORESETPoolIndex value by DCI or RRC signaling, and then will be associated with a failure detection resource set. For example, in the case that the PUSCH transmission occasion for carrying the MAC CE of TRP-specific BFR of a failed TRP is scheduled or activated by a DCI, the scheduling or activating DCI is received in a CORESET with a CORESETPoolIndex value associated with the other of the two failure detection resource sets. In another example, the configured grant PUSCH transmission occasion for carrying the MAC CE of TRP-specific BFR of a failed TRP is configured to be associated with a CORESETPoolIndex value or a SRS resource set associated with the other of the two failure detection resource sets by RRC signaling.

Since only two TRPs are supported in R16/R17 now, embodiments of the present application mainly use two TRPs for illustration. It should be noted that more than two TRPs can also be supported by using the methods disclosed in the specification.

Based on the above basic solutions, considering that TRP-specific BFR may be supported in single DCI based multiple TRPs (Scenario 1) and multiple DCIs based multiple TRPs (Scenario 2) , more detailed embodiments will be illustrated at least to show how to enhance beam failure recovery in multi-TRP transmission in view of the above two scenarios.

Scenario 1: Single DCI based multiple TRPs

In Scenario 1, according to some embodiments of the present application, two failure detection resource sets, e.g., two BFD-RS sets will be configured for TRP-specific BFR, and two SRS resource sets are configured for PUSCH transmission, wherein both of the two SRS resource sets are configured as usage "codebook" or "non-codebook. " Each SRS resource set is one to one associated with a BFD-RS set by a predefined rule or RRC signaling. According to some other embodiments of the present application, two CORESETGroupIndex values for CORESETs may also be configured in Scenario 1 which means each CORESET is associated with one CORESETGroupIndex value, wherein the two CORESETGroupIndex values are one to one associated with the two SRS resource sets and the two failure detection resource sets respectively. Accordingly, the two SRS resource sets and the two failure detection resource sets will be one to one associated via their respective one to one association with the two CORESETGroupIndex values.

For a PUSCH transmission in Scenario 1, it can be configured or indicated as "repeated" or "not repeated. " When a PUSCH transmission is transmitted one shot or it is transmitted with a single beam, it is indicated with which SRS resource set the PUSCH transmission is associated. When a PUSCH transmission is a PUSCH transmission with repetitions by using multiple beams as supported in R17, 2 SRS resource sets are configured to be associated with the PUSCH transmission with repetitions. In this case, a beam mapping pattern will be configured for a PUSCH with repetition by using multiple beams, wherein each repetition of a PUSCH transmission with repetitions by using multiple beams is associated with one SRS resource set. The beam mapping pattern can be that according to R16 URLLC PDSCH Scheme 4, e.g., the cyclical mapping pattern, or the sequential mapping pattern. The mapping pattern for the SRS resource sets and the plurality of PUSCH repetitions (or PUSCH transmission repetitions) can be any mapping pattern, which is similar to a beam mapping pattern, e.g., the cyclical mapping pattern, or the sequential mapping pattern.

According to some embodiments of the present application, a PUSCH transmission carrying a MAC CE of TRP-specific BFR can be a DCI scheduled PUSCH. The DCI scheduling the PUSCH will indicate with which SRS resource set of the two SRS resource sets the PUSCH transmission is associated, e.g., by associated bit (s) in the SRI field of the DCI scheduling the PUSCH. The associated bit (s) can be a new bit added into the SRI field in view of legacy DCI to indicate with which SRS resource set the PUSCH transmission is associated. For example, in the case that the new bit is set as "0, " it indicates that the PUSCH is associated the SRS resource set with a lower index of the two SRS resource sets. In the case that the new bit is set as "1, " it indicates that the PUSCH is associated with the SRS resource set with a higher index of the two SRS resource sets.

According to some other embodiments of the present application, a PUSCH transmission carrying a MAC CE of TRP-specific BFR can be a Type 1 configured grant PUSCH. For Type 1 configured grant PUSCH, all parameters related to the Type 1 configured grant PUSCH are configured by RRC signaling. Therefore, a RRC signaling will indicate with which SRS resource set this Type 1 configured grant PUSCH is associated in various manners. For example, a SRS resource set index is directly configured in the configuration information of a Type 1 configured grant PUSCH, or a bit is added into the SRI field in view of the legacy RRC signalling, which is similar to the SRI field in DCI scheduled PUSCH. In the case that CORESETGroupIndex values are configured for CORESETs in Scenario 1, besides the above manners, the PUSCH transmission may be configured to be associated with a corresponding CORESETGroupIndex value by the RRC signaling. Since the two CORESETGroupIndex values are one to one associated with the two SRS resource sets and the two failure detection resource sets, the PUSCH transmission will be associated with the corresponding SRS resource set.

According to some yet other embodiments of the present application, a PUSCH transmission carrying a MAC CE of TRP-specific BFR can be a Type 2 configured PUSCH. For a Type 2 configured grant PUSCH, some parameters are configured in RRC signaling, while the remaining parameters are indicated by a DCI activating the PUSCH transmission. Accordingly, the RRC signaling or DCI can be used to indicate with which SRS resource set a Type 2 configured PUSCH grant PUSCH is associated. For a manner of using RRC signaling, a SRS resource set index can be configured in the configuration of a Type 2 configured grant PUSCH. For a manner of using DCI, it can be the same as that used in DCI scheduled PUSCH, e.g., by adding a new bit into the SRI field to indicate with which SRS resource set the PUSCH transmission is associated. In the case that CORESETGroupIndex values are configured for CORESETs in Scenario 1, besides the above manners, the Type 2 configured PUSCH may be configured to be associated with a corresponding CORESETGroupIndex value by RRC signalling in a similar manner as illustrated in Type 1 configured grant PUSCH.

A PUSCH transmission occasion is defined as a PUSCH transmission without repetition, a repetition of a PUSCH transmission with repetition by using one beam, or a repetition of a PUSCH transmission with repetition by using multiple beams in Scenario 1. Accordingly, based on the above association between SRS resource set and PUSCH transmission, each PUSCH transmission occasion can be associated with a SRS resource set of the two SRS resource sets in various manners as stated above, e.g., being configured by RRC signaling or indicated by DCI. Since each SRS resource set is one to one associated with a failure detection resource set and a PUSCH transmission occasion can be indicated to be associated with a SRS resource set, a PUSCH transmission occasion can also be associated with a failure detection resource set. Similarly, in the case that CORESETGroupIndex values are configured, a PUSCH transmission occasion can also be associated with a failure detection resource set. Therefore, when a UE detects that all beams in a BFD-RS set are failed, it will transmit a MAC CE of TRP-specific BFR in a PUSCH transmission occasion which is associated with the other of the two BFD-RS sets. The MAC CE of TRP-specific BFR indicates that all beams in the BFD-RS set are failed, and the corresponding new beam index if it can be found (or no new beam indication corresponding to the BFD-RS) .

FIG. 3 illustrates an exemplary diagram of MAC CE of TRP-specific BFR transmission in Scenario 1 according to some embodiments of the present application.

As shown in FIG. 3, two failure detection resource sets, e.g., BFD-RS set 0 and BFD-RS set 1 are configured for TRP-specific BFR. Two SRS resource sets, e.g., SRS resource set 0 and SRS resource set 1 are configured for PUSCH transmission. SRS resource set 0 can be associated with BFD-RS set 0 and SRS resource set 1 can be associated with BFD-RS set 1 by a predefined rule or RRC signaling respectively. At time t0, a UE detects that all radio link qualities of the BFD-RSs in BFD-RS set 0 are worse than a threshold configured in RRC signaling, that is, all beams of BFD-RS set 0 are failed. It is assumed that, at time t1, a PUSCH transmission occasion, e.g., PUSCH 1 without repetition will be transmitted, which is scheduled by a DCI. The DCI scheduling PUSCH 1 also indicates that PUSCH 1 is associated with SRS resource set 0. It is assumed that, at time t2, another PUSCH transmission occasion, e.g., PUSCH 2 without repetition will transmitted, which is configured to be a Type 1 grant PUSCH by RRC signaling. The RRC signalling also indicates that PUSCH 2 is associated with SRS resource set 1. Accordingly, PUSCH 1 is associated with BFD-RS set 0 and PUSCH 2 is associated with BFD-RS set 1 in view of their association with SRS resource set 0 and SRS resource set 1.

Since all beams in BFD-RS set 0 are failed at t0, a MAC CE of TRP-specific BFR associated with BFD-RS set 0 will be transmitted. The MAC CE indicates that all beams in BFD-RS set 0 are failed, and the corresponding new beam index in the case that a new beam can be found (or no new beam indication if a new beam cannot be found) . As stated above, since PUSCH 1 is associated with BFD-RS set 0 and PUSCH 2 is associated with BFD-RS set 1, the MAC CE of TRP-specific BFR associated with BFD-RS set 0 will be transmitted in the PUSCH transmission occasion associated with the other BFD-RS set, i.e., PUSCH 2 at t2. Since BFD-RS set 1 is not beam failed, the MAC CE of TRP-specific BFR associated with BFD-RS set 0 will be successfully transmitted. Accordingly, the latency of TRP beam failure recovery will be reduced and the whole throughput of the multi-TRP communication system will be increased.

Scenario 2: Multiple DCIs based multiple TPRs

In Scenario 2, according to some embodiments of the present application, two failure detection resource sets, e.g., two BFD-RS sets will be implicitly or explicitly configured for TRP-specific BFR, wherein each BFD-RS set is associated with a CORESETPoolIndex value. In addition, two SRS resource sets are configured for PUSCH transmission, wherein both of the two SRS resource sets are configured as usage "codebook" or "non-codebook. " Meanwhile, each SRS resource set is one to one associated with a CORESETPoolIndex value by a predefined rule or RRC signaling. Since each BFD-RS set is one to one associated with a CORESETPoolIndex value and each SRS resource set is one to one associated with a CORESETPoolIndex value too, each SRS resource set can be one to one associated with a BFD-RS set due to being associated with the same CORESETPoolIndex value.

In Scenario 2, a PUSCH transmission can only be transmitted by a single beam. Since there are two SRS resource sets configured for a PUSCH transmission, it needs to indicate with which SRS resource set a PUSCH transmission with a single beam is associated. A PUSCH transmission occasion is defined as a repetition of a PUSCH transmission by using one beam or a PUSCH transmission without repetition.

According to some other embodiments of the present application, a PUSCH transmission occasion carrying a MAC CE of TRP-specific BFR can be DCI scheduled PUSCH. Since the DCI scheduling the PUSCH is transmitted in a CORESET associated with a CORESETPoolIndex value, the scheduled PUSCH is associated with the CORESETPoolIndex value too. Therefore, a DCI scheduled PUSCH is always associated with a CORSETPoolIndex value. Since each SRS resource set is one to one associated with a CORESETPoolIndex value, a DCI scheduled PUSCH will be associated with a SRS resource set due to their association with the same CORESETPoolIndex value. In this case, a DCI can implicitly indicate with which SRS resource set the PUSCH scheduled by the DCI is associated.

According to some other embodiments of the present application, a PUSCH transmission occasion carrying a MAC CE of TRP-specific BFR can be a Type 1 configured grant PUSCH. For Type 1 configured grant PUSCH, all parameters related to Type 1 configured grant PUSCH are configured by RRC signaling. Therefore, a RRC signaling will indicate with which SRS resource set this Type 1 configured grant PUSCH is associated in various manners. For example, a SRS resource set index or a CORESETPoolIndex value is configured in the configuration information of a Type 1 configured grant PUSCH, or a bit is added in the SRI field in view of the legacy RRC signaling to indicate with which SRS resource set or CORESETPoolIndex value the PUSCH is associated. By the RRC signaling, a Type 1 configured grant PUSCH is indicated to be associated with a SRS resource set of two SRS resource set or a CORESETPoolIndex value of two CORESETPoolIndex values. For example, the RRC signaling can explicitly indicates that a Type 1 configured grant PUSCH is associated with a SRS resource set. In the case that the RRC signaling indicates that a Type 1 configured grant PUSCH is associated with a CORESETPoolIndex value, the Type 1 configured grant PUSCH can be associated with a SRS resource set in view of the one to one association between each SRS resource set and each CORESETPoolIndex value. That is, a Type 1 configured grant PUSCH is implicitly indicated to be associated with a SRS resource set by the RRC signaling.

According to some yet other embodiments of the present application, a PUSCH transmission occasion carrying a MAC CE of TRP-specific BFR can be a Type 2 configured grant PUSCH. For a Type 2 configured grant PUSCH, some parameters are configured in RRC signaling, while the remaining parameters are indicated by a DCI activating the PUSCH transmission. According to some embodiments of the present application, RRC signaling or DCI can be used to indicate with which SRS resource set a Type 2 configured PUSCH grant PUSCH is associated. For a manner of using RRC signaling, a SRS resource set index or a CORESETPoolIndex value can be configured in the configuration of a Type 2 configured grant PUSCH. Since there is a one to one association between each SRS resource set and each CORESETPoolIndex value, the RRC signaling can indicate that a Type 2 configured grant PUSCH is associated with a SRS resource set. While for a manner of using DCI, it can be the same as that used in DCI scheduled PUSCH, which means a Type 2 configured grant PUSCH is associated with a CORESETPoolIndex value of the CORESET where the DCI activating the PUSCH is transmitted. Since there is a one to one association between each SRS resource set and each CORESETPoolIndex value, the activating DCI can implicitly indicate that a Type 2 configured grant PUSCH is associated with a SRS resource set.

Since each SRS resource set or CORESETPoolIndex value is one to one associated with a failure detection resource set and a PUSCH transmission occasion can be indicated to be associated with a SRS resource set or CORESETPoolIndex value, a PUSCH transmission occasion can always be associated with a BFD-RS set. When a UE detects that all beams in a BFD-RS set are failed, it will transmit a MAC CE of TRP-specific BFR in a PUSCH transmission occasion which is associated with the other of the two BFD-RS sets. The MAC CE of TRP-specific BFR indicates that all beams in the BFD-RS set are failed, and the corresponding new beam index if it can be found (or no new beam indication corresponding to the BFD-RS) .

FIG. 4 illustrates an exemplary diagram of MAC CE of TRP-specific BFR transmission in Scenario 2 according to some embodiments of the present application.

As shown in FIG. 4, two failure detection resource sets, e.g., BFD-RS set 0 and BFD-RS set 1 are configured for TRP-specific BFR, and two CORESETPoolIndex values, e.g., CORESETPoolIndex 0 and CORESETPoolIndex 1 are configured for CORESETs, wherein BFD-RS set 0 is associated with CORESETPoolIndex 0 and BFD-RS set 1 is associated with CORESETPoolIndex 1. In addition, two SRS resource sets, e.g., SRS resource set 0 and SRS resource set 1 are configured for PUSCH transmission, wherein SRS resource set 0 and SRS resource set 1 are associated with CORESETPoolIndex 0 and CORESETPoolIndex 1 respectively. At time t0, a UE detects that all radio link qualities of the BFD-RSs in BFD-RS set 1 are worse than a predefined threshold, that is, all beams of BFD-RS set 1 are failed. It is assumed that, at time t1, a PUSCH transmission occasion, e.g., PUSCH 1 without repetition will be transmitted, which is scheduled by a DCI. The DCI scheduling PUSCH 1 also indicates that PUSCH 1 is associated with SRS resource set 0. It is assumed that, at time t2, another PUSCH transmission occasion, e.g., PUSCH 2 without repetition will transmitted, which is configured to be a Type 2 grant PUSCH. The DCI activating PUSCH 2 indicates that PUSCH 2 is associated with SRS resource set 1. Accordingly, PUSCH 1 is associated with BFD-RS set 0 and PUSCH 2 is associated with BFD-RS set 1.

Since all beams in BFD-RS set 1 are failed in t0, a MAC CE of TRP-specific BFR associated with BFD-RS set 1 will be transmitted. The MAC CE indicates that all beams in BFD-RS set 1 are failed and the corresponding new beam index in the case that a new beam can be found (or no new beam indication if a new beam cannot be found) . As stated above, since PUSCH 1 is associated with BFD-RS set 0 and PUSCH 2 is associated with BFD-RS set 1, the MAC CE of TRP-specific BFR associated with BFD-RS set 1 will be transmitted in the PUSCH transmission occasion associated with the other BFD-RS set, i.e., PUSCH 1 in t1. Since BFD-RS set 0 associated with PUSCH 1 is not beam failed, the MAC CE of TRP-specific BFR associated with BFD-RS set 1 will be successfully transmitted in PUSCH 1. Accordingly, the latency of TRP beam failure recovery will be reduced and the whole throughput of the multi-TRP communication system will be increased.

Embodiments of the present application also propose an apparatus for beam failure recovery. For example, FIG. 5 illustrates a block diagram of an apparatus 700 for beam failure recovery according to some embodiments of the present application.

FIG. 5 illustrates a simplified block diagram of an apparatus 500 for beam link recovery in multi-TRP transmission according to some embodiments of the present application. The apparatus 500 may be a BS 101 or a UE 105 (for example, UE 105a, UE 105b, or UE 105c) as shown in FIG. 1.

As shown in FIG. 5, the apparatus 500 may include at least one non-transitory computer-readable medium 502, at least one receiving circuitry 504, at least one transmitting circuitry 506, and at least one processor 508 coupled to the non-transitory computer-readable medium 502, the receiving circuitry 504 and the transmitting circuitry 506. The apparatus 500 may be a network side apparatus (e.g., a BS) configured to perform a method illustrated in any one of FIG. 2 and the like, or a remote unit (e.g., a UE) configured to perform a method illustrated in any one of FIG. 2 or the like.

Although in this figure, elements such as the at least one processor 508, transmitting circuitry 506, and receiving circuitry 504 are described in the singular, the plural is contemplated unless a limitation to the singular is explicitly stated. In some embodiments of the present application, the receiving circuitry 504 and the transmitting circuitry 506 can be combined into a single device, such as a transceiver. In certain embodiments of the present application, the apparatus 500 may further include an input device, a memory, and/or other components.

For example, in some embodiments of the present application, the non-transitory computer-readable medium 502 may have stored thereon computer-executable instructions to cause a processor to implement the method with respect to the UE as described above. For example, the computer-executable instructions, when executed, cause the processor 508 interacting with receiving circuitry 504 and transmitting circuitry 506, so as to perform the steps with respect to the UE depicted in FIG. 2.

In some embodiments of the present application, the non-transitory computer-readable medium 502 may have stored thereon computer-executable instructions to cause a processor to implement the method with respect to the BS as described above. For example, the computer-executable instructions, when executed, cause the processor 508 interacting with receiving circuitry 504 and transmitting circuitry 506, so as to perform the steps with respect to the BS depicted in FIG. 2.

The method according to embodiments of the present application can also be implemented on a programmed processor. However, the controllers, flowcharts, and modules may also be implemented on a general purpose or special purpose computer, a programmed microprocessor or microcontroller and peripheral integrated circuit elements, an integrated circuit, a hardware electronic or logic circuit such as a discrete element circuit, a programmable logic device, or the like. In general, any device on which resides a finite state machine capable of implementing the flowcharts shown in the figures may be used to implement the processor functions of this application. For example, an embodiment of the present application provides an apparatus for beam failure recovery, including a processor and a memory. Computer programmable instructions for implementing a method are stored in the memory, and the processor is configured to perform the computer programmable instructions to implement the method. The method may be a method as stated above or other method according to an embodiment of the present application.

An alternative embodiment preferably implements the methods according to embodiments of the present application in a non-transitory, computer-readable storage medium storing computer programmable instructions. The instructions are preferably executed by computer-executable components preferably integrated with a network security system. The non-transitory, computer-readable storage medium may be stored on any suitable computer readable media such as RAMs, ROMs, flash memory, EEPROMs, optical storage devices (CD or DVD) , hard drives, floppy drives, or any suitable device. The computer-executable component is preferably a processor but the instructions may alternatively or additionally be executed by any suitable dedicated hardware device. For example, an embodiment of the present application provides a non-transitory, computer-readable storage medium having computer programmable instructions stored therein. The computer programmable instructions are configured to implement a method as stated above or other method according to an embodiment of the present application.

While this application has been described with specific embodiments thereof, it is evident that many alternatives, modifications, and variations may be apparent to those skilled in the art. For example, various components of the embodiments may be interchanged, added, or substituted in the other embodiments. Also, all of the elements of each figure are not necessary for operation of the disclosed embodiments. For example, one of ordinary skill in the art of the disclosed embodiments would be enabled to make and use the teachings of the application by simply employing the elements of the independent claims. Accordingly, embodiments of the application as set forth herein are intended to be illustrative, not limiting. Various changes may be made without departing from the spirit and scope of the application.

Claims

A method, comprising:

receiving configuration information at least indicating:

two failure detection resource sets; and

two sounding reference signal (SRS) resource sets for physical uplink shared channel (PUSCH) transmission, wherein the two SRS resource sets are one to one associated with the two failure detection resource sets; and

transmitting a medium access control (MAC) control element (CE) corresponding to that a radio link quality of all failure detection resources in one of the two failure detection resource sets is lower than a threshold, in a PUSCH transmission occasion being associated with a SRS resource set associated with the other of the two failure detection resource sets.
The method of claim 1, wherein the PUSCH transmission occasion is indicated to be associated with the SRS resource set associated with the other of the two failure detection resource sets via a downlink control information (DCI) scheduling or activating the PUSCH transmission occasion.
The method of claim 1, wherein the PUSCH transmission occasion is configured to be associated with the SRS resource set associated with the other of the two failure detection resource sets by radio resource control (RRC) signaling.
The method of claim 1, wherein the configuration information further indicates two CORESETGroupIndex values for control resource sets (CORESETs) , wherein the two CORESETGroupIndex values are one to one associated with the two SRS resource sets and the two failure detection resource sets, and the PUSCH transmission occasion is configured to be associated with a CORESETGroupIndex value associated with the other of the two failure detection resource sets.
The method of claim 1, wherein the configuration information further indicates two CORESETPoolIndex values for control resource sets (CORESETs) , wherein the two CORESETPoolIndex values are one to one associated with the two SRS resource sets and the two failure detection resource sets.
The method of claim 5, wherein in the case that the PUSCH transmission occasion is scheduled or activated by a downlink control information (DCI) , the DCI is received in a CORESET with a CORESETPoolIndex value associated with the other of the two failure detection resource sets.
The method of claim 6, wherein the PUSCH transmission occasion is configured to be associated with a CORESETPoolIndex value or a SRS resource set associated with the other of the two failure detection resource sets by radio resource control (RRC) signaling.
A method, comprising:

transmitting configuration information at least indicating:

two failure detection resource sets; and

two sounding reference signal (SRS) resource sets for physical uplink shared channel (PUSCH) transmission, wherein the two SRS resource sets are one to one associated with the two failure detection resource sets; and

receiving a medium access control (MAC) control element (CE) corresponding to that a radio link quality of all failure detection resources in one of the two failure detection resource sets is lower than a threshold, in a PUSCH transmission occasion being associated with a SRS resource set associated with the other of the two failure detection resource sets.
The method of claim 8, wherein the PUSCH transmission occasion is indicated to be associated with the SRS resource set associated with the other of the two failure detection resource sets via a downlink control information (DCI) scheduling or activating the PUSCH transmission occasion .
The method of claim 8, wherein the PUSCH transmission occasion is configured to be associated with the SRS resource set associated with the other of the two failure detection resource sets by radio resource control (RRC) signaling.
The method of claim 8, wherein the configuration information further indicates two CORESETGroupIndex values for control resource sets (CORESETs) , wherein the two CORESETGroupIndex values are one to one associated with the two SRS resource sets and the two failure detection resource sets, and the PUSCH transmission occasion is configured to be associated with a CORESETGroupIndex value associated with the other of the two failure detection resource sets.
The method of claim 8, wherein the configuration information further indicates two CORESETPoolIndex values for control resource sets (CORESETs) , wherein the two CORESETPoolIndex values are one to one associated with the two SRS resource sets and the two failure detection resource sets.
The method of claim 12, wherein in the case that the PUSCH transmission occasion is scheduled or activated by a downlink control information (DCI) , the DCI is transmitted in a CORESET with a CORESETPoolIndex value associated with the other of the two failure detection resource sets.
The method of claim 13, wherein the PUSCH transmission occasion is configured to be associated with a CORESETPoolIndex value or a SRS resource set associated with the other of the two failure detection resource sets by radio resource control (RRC) signaling.
An apparatus, comprising:

at least one non-transitory computer-readable medium having computer executable instructions stored therein;

at least one receiving circuitry;

at least one transmitting circuitry; and

at least one processor coupled to the at least one non-transitory computer-readable medium, the at least one receiving circuitry and the at least one transmitting circuitry;

wherein the computer executable instructions are programmed to implement a method according to any one of Claims 1-14 with the at least one receiving circuitry, the at least one transmitting circuitry and the at least one processor.