Method and apparatus for beam failure detection and recovery in sidelink

Abstract

Embodiments of the present application relate to a method and apparatus for beam failure detection and recovery in a sidelink. An exemplary method includes: obtaining configuration information for a beam failure recovery (BFR) procedure on the sidelink, where the configuration information indicates a periodic window; and according to the configuration information, receiving at least one transmission of a beam failure detection reference signal (BFD-RS) on the sidelink within the periodic window. Embodiments of the present application can efficiently reduce the latency and signaling overhead of BFR in the sidelink.

Description

Technical Field

[0001] Embodiments of the present application generally relate to wireless communication technologies, and in particular, to a method and apparatus for beam failure detection and recovery in a sidelink. Background Art

[0002] To meet the growing quality of service (QoS) requirements for sidelink communication, operating in the millimeter wave (i.e., mmWave) band or even the terahertz (i.e., THz) band has become a promising solution, because such bands are expected to provide high capacity and support high data rate connections as well as latency-sensitive data exchange.

[0003] Although mmWave / THz communication is very attractive from the perspective of data throughput, it poses challenges to the physical layer. For example, due to high propagation losses, the use of the mmWave / THz band is considered mainly suitable for short distances (e.g., a few hundred meters) and point-to-point line-of-sight (LoS) communication. To maintain the required communication range, it is assumed that a directional antenna system is used when operating in the mmWave / THz band to compensate for the high propagation losses.

[0004] Therefore, the industry needs an improved technology for efficient beam management (e.g., beam failure detection and beam failure recovery) in sidelink systems, especially in sidelink systems operating in the mmWave / THz band. Summary of the Invention

[0005] Some embodiments of the present application at least provide technical solutions for beam failure detection and recovery in a sidelink.

[0006] According to some embodiments of the present application, a method may include: obtaining configuration information for a beam failure recovery (BFR) procedure on a sidelink, where the configuration information indicates a periodic window; and according to the configuration information, receiving at least one transmission of a beam failure detection reference signal (BFD-RS) on the sidelink within the periodic window.

[0007] According to some other embodiments of the present application, a method may include: obtaining configuration information for a BFR procedure on a sidelink, where the configuration information indicates a periodic window; and according to the configuration information, transmitting at least one transmission of a BFD-RS on the sidelink within the periodic window.

[0008] According to some other embodiments of the present application, a method may include: transmitting configuration information for a BFR procedure on a sidelink, where the configuration information indicates a periodic window, and according to the configuration information, at least one transmission of a BFD-RS is within the periodic window.

[0009] Some embodiments of the present application also provide an apparatus, which includes: at least one non-transitory computer-readable medium, in which computer-executable instructions are stored; at least one receiver; at least one transmitter; and at least one processor, which is coupled to the at least one non-transitory computer-readable medium, the at least one receiver, and the at least one transmitter. The computer-executable instructions are programmed to implement any of the methods described above by using the at least one receiver, the at least one transmitter, and the at least one processor.

[0010] Embodiments of the present application provide a technical solution for beam failure detection and recovery in the sidelink, which can reduce the delay and signaling overhead of BFR in the sidelink. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] To describe the manner in which the advantages and features of the present application can be obtained, the description of the present application is made with reference to specific embodiments thereof, which are illustrated in the accompanying drawings. These drawings only depict exemplary embodiments of the present application and should not be considered as limiting its scope.

[0012] Figure 1 is a schematic diagram of an exemplary wireless communication system 100 according to some embodiments of the present application;

[0013] Figure 2 is a schematic diagram illustrating a beam failure in the sidelink according to some embodiments of the present application;

[0014] Figure 3 is a flowchart of a method for beam failure detection and recovery in the sidelink according to some embodiments of the present application;

[0015] Figure 4 is a flowchart of a method for beam failure detection and recovery in the sidelink according to some other embodiments of the present application;

[0016] Figure 5 illustrates an example of BFD-RS transmission in the time domain according to some embodiments of the present application;

[0017] Figure 6 illustrates another example of BFD-RS transmission in the time domain according to some other embodiments of the present application;

[0018] Figure 7 illustrates another example of BFD-RS transmission in the time domain according to some other embodiments of the present application;

[0019] Figure 8Illustrate an example of a BFD report in the time domain according to some embodiments of the present application;

[0020] Figure 9 Illustrate an example of initiating a beam failure recovery procedure according to some embodiments of the present application;

[0021] Figure 10 Illustrate an example of detecting events of a beam reselection procedure according to some embodiments of the present application;

[0022] Figure 11 Illustrate an example of initiating a beam reselection procedure according to some embodiments of the present application; and

[0023] Figure 12 Illustrate a simplified block diagram of apparatus 1200 for beam failure detection and recovery in a sidelink according to some embodiments of the present application. Detailed Description of the Invention

[0024] The detailed description of the drawings is intended as a description of the currently 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 implemented by different embodiments, which are intended to be included within the spirit and scope of the present application.

[0025] Reference will now be made in detail to some embodiments of the present application, examples of which are illustrated in the accompanying drawings. For ease of understanding, the embodiments are provided in a specific network architecture and new service scenario, such as 3GPP 5G, 3GPP LTE Release 8, etc. Consider that as the network architecture and new service scenario evolve, all embodiments in the present application are also applicable to similar technical problems; and furthermore, the terms cited in the present application may change, which will not affect the principles of the present application.

[0026] Figure 1 is a schematic diagram of an exemplary wireless communication system 100 according to an embodiment of the present application.

[0027] As Figure 1 shown, the wireless communication system 100 includes at least one user equipment (UE) 101 and at least one base station (BS) 102. Specifically, for illustrative purposes, the wireless communication system 100 includes two UEs 101 (e.g., UE 101a and UE 101b) and one BS 102. Although a specific number of UEs 101 and BSs 102 are depicted in Figure 1 it, consider that any number of UEs 101 and BSs 102 may be included in the wireless communication system 100.

[0028] According to some embodiments of the present application, the UE 101 may include a computing device, such as a desktop computer, a laptop computer, a personal digital assistant (PDA), a tablet computer, a smart TV (e.g., a TV connected to the Internet), a set-top box, a game console, a security system (including security cameras), an in-vehicle computer, etc. According to some embodiments of the present application, the UE 101 may include a portable wireless communication device, a smart phone, a cellular phone, a flip phone, a device with a subscriber identity module, a personal computer, a selective call receiver, or any other device capable of transmitting and receiving communication signals over a wireless network.

[0029] According to some embodiments of the present application, the UE 101 may include a vehicle UE (V-UE), a vulnerable road user device (VRU), a public safety UE (PS-UE), and / or a commercial sidelink UE (CS-UE). In an embodiment of the present application, the VRU may include a pedestrian UE (P-UE), a cyclist UE, a wheelchair UE, or other UEs that require energy conservation compared to the V-UE. According to some embodiments of the present application, the UE 101 includes wearable devices, such as a smart watch, a fitness band, an optical head-mounted display, etc. In addition, the UE 101 may be referred to as a subscriber unit, a mobile device, a mobile station, a user, a terminal, a mobile terminal, a wireless terminal, a fixed terminal, a subscriber station, a user terminal or device, or described using other terms used in this technology. The UE 101 may communicate directly with the BS 102 via an LTE or NR Uu interface.

[0030] According Figure 1 to some embodiments, the UE 101a functions as a transmitting (Tx) UE, and the UE 101b functions as a receiving (Rx) UE. The UE 101a may exchange V2X messages with the UE 101b via a sidelink (e.g., the PC5 interface defined in 3GPP TS 23.303). The UE 101a may transmit information or data to other UEs within the V2X communication system via sidelink unicast, sidelink multicast, or sidelink broadcast. For example, the UE 101a transmits data to the UE 101b in a sidelink unicast session. The UE 101a may transmit data to the UE 101b and other UEs in a multicast group ( Figure 1 (not shown in the figure)) via a sidelink multicast transmission session. In addition, the UE 101a may transmit data to the UE 101b and other UEs ( Figure 1 (not shown in the figure)) via a sidelink broadcast transmission session. Alternatively, according Figure 1 to some other embodiments, the UE 101b functions as a Tx UE and transmits V2X messages, and the UE 101a functions as an Rx UE and receives V2X messages from the UE 101b.

[0031] Figure 1 In the embodiments of both UE 101a and UE 101b, information can be transmitted to BS 102 via the LTE or NR Uu interface, and control information can be received from BS 102. BS 102 can be distributed over a geographical area. In a particular embodiment of the present application, each of BS 102 can also be referred to as an access point, access terminal, base, base unit, macro cell, Node B, evolved Node B (eNB), gNB, home Node B, relay node or device, or described using other terms used in this technology. BS 102 is generally part of a radio access network, which may include one or more controllers communicatively coupled to one or more corresponding BS 102.

[0032] The wireless communication system 100 can be compatible with any type of network capable of sending and receiving wireless communication signals. For example, the wireless communication system 100 is compatible with wireless communication networks, cellular phone networks, time division multiple access (TDMA)-based networks, code division multiple access (CDMA)-based networks, orthogonal frequency division multiple access (OFDMA)-based networks, LTE networks, 3GPP-based networks, 3GPP 5G networks, satellite communication networks, high altitude platform networks, and / or other communication networks.

[0033] In some embodiments of the present application, the wireless communication system 100 is compatible with 5G NR of the 3GPP protocol, where BS102 transmits data using an OFDM modulation scheme on the downlink (DL), and UE 101 transmits data using a discrete Fourier transform-spread-orthogonal frequency division multiplexing (DFT-S-OFDM) or cyclic prefix OFDM (CP-OFDM) scheme on the uplink (UL) or sidelink (SL). However, more generally, the wireless communication system 100 can implement some other open or proprietary communication protocols, such as WiMAX and other protocols.

[0034] In some embodiments of the present application, BS 102 can communicate using other communication protocols (such as the IEEE 802.11 series of wireless communication protocols). In addition, in some embodiments of the present application, BS 102 can communicate through licensed spectrum, while in other embodiments, BS 102 can communicate through unlicensed spectrum. The present application is not intended to be limited to the implementation of any specific wireless communication system architecture or protocol. In still other embodiments of the present application, BS 102 can communicate with UE 101 using the 3GPP 5G protocol.

[0035] In the case of beam-based communication between the BS 102 and the UE 101, a sudden change in the radio environment may degrade or even interrupt the communication link (i.e., the Uu link) between the BS 102 and the UE 101. The use of narrow beams will further exacerbate the degradation of link quality due to blockage. When a beam failure occurs in the Uu link, the BFR procedure can be used for the Uu link to recover from the connection interruption.

[0036] For the Uu link, the BFR procedure can work as follows: (1) The UE monitors the quality of the downlink control channel by estimating a set of periodic reference signals and declares a beam failure once the perceived quality is insufficient to maintain reliable communication; (2) Then, the UE initiates recovery to indicate the failure and the new suitable beam to the BS. When a beam failure is declared for a specific Uu link, the UE cannot transmit through the specific Uu link. Therefore, the UE must initiate the BFR procedure by reusing the random access (RA) procedure.

[0037] Both contention-based random access (CBRA) and contention-free random access (CFRA) support the BFR procedure in the Uu link. In the case of CBRA-based BFR, a contention solution is needed since multiple users randomly select preambles from a shared preamble pool. In the case of CFRA-based BFR, dedicated preambles are pre-allocated to each UE and thus no contention solution is needed.

[0038] The above BFR procedure in the Uu link may not be applicable to BFR in the sidelink. For example, Figure 2 is a schematic diagram illustrating beam failure in the sidelink according to some embodiments of the present application.

[0039] Refer to Figure 2 Figure 2 The system 100 in Figure 1 can be the same as the system in

[0040] ​First, using periodic reference signals for beam failure detection in the Uu link leads to inefficient resource utilization for the case of sidelink non-periodic traffic, because the transmission pattern of non-periodic traffic is unpredictable. Second, RA-based BFR pairs from a fully interrupted connection cause intolerable delays to sidelink traffic, which is typically associated with driving safety scenarios. In addition, CBRA-based BRF requires a contention solution, which is difficult for sidelink communication, especially in Mode 2 specified in the 3GPP standard document, where the UE autonomously selects resources for sidelink communication. CFRA-based BFR does not require a contention solution, but requires a large number of preambles to enable multiple pairs of UEs to communicate simultaneously via the sidelink in a given area.

[0041] In view of the above, due to the introduction of intolerable delays, high signaling overhead, inefficient resource utilization, and complex contention solutions, applying the BFR mechanism in the Uu link to the sidelink scenario is challenging.

[0042] Therefore, embodiments of the present application provide a technical solution for beam failure detection and recovery in the sidelink, which can reduce the delay and signaling overhead of BFR in the sidelink. More details of the embodiments of the present application will be illustrated below in conjunction with the drawings.

[0043] According to some embodiments of the present application, a UE (e.g., a Tx UE or an Rx UE) may obtain configuration information of a BFR procedure on the sidelink. The configuration information may include configurations for BFD-RS transmission and for BFD reporting. The BFD-RS in the sidelink may also be referred to as SL BFD-RS. The SL BFD-RS may be used for beam failure detection in the sidelink (i.e., SLBFD), which is performed by evaluating the quality of the SL BFD-RS. The step of obtaining the configuration information may be Figure 3 step 301 in Figure 4 or step 401 in

[0044] For example, Figure 3 is a flowchart illustrating a method for beam failure detection and recovery in the sidelink according to some embodiments of the present application. Figure 3 The method in Figure 4 is a flowchart illustrating a method for beam failure detection and recovery in the sidelink according to some other embodiments of the present application. Figure 4 The method in

[0045] According to some embodiments of the present application, obtaining configuration information may include receiving configuration information transmitted from BS 102. In an embodiment of the present application, the configuration information may be transmitted via Radio Resource Control (RRC) signaling. That is, a UE (e.g., a Tx UE or an Rx UE) may receive the configuration information via RRC signaling transmitted from BS 102.

[0046] According to some other embodiments of the present application, the configuration information may be pre-configured in a UE (e.g., a Tx UE or an Rx UE), such as in a Subscriber Identity Module (SIM), in a Universal Subscriber Identity Module (USIM), or in the memory of the UE. Thus, obtaining the configuration information may refer to accessing the SIM, USIM, or memory to obtain the configuration information inside the UE.

[0047] According to some embodiments of the present application, obtaining the configuration information may include receiving the configuration information via RRC signaling transmitted from another UE different from the UE.

[0048] According to some embodiments of the present application, the configuration for BFD-RS transmission included in the configuration information may indicate a periodic window. The periodic window for BFD-RS transmission may be semi-statically configured such that, according to the configuration information, resources for transmitting SL BFD-RS are subject to the availability of transmission within the periodic window. In an embodiment of the present application, the configuration for BFD-RS transmission may indicate at least one of the following: the timing type of the BFD-RS, where the timing type is one of pseudo-periodic and pseudo-semi-persistent; the RS type of the BFD-RS, where the RS type is one of a synchronization signal, a Physical Broadcast Channel (PBCH) block (SSB), and a Channel State Information (CSI) reference signal (CSI-RS); the length of the periodic window; the minimum number of transmissions within each window of the periodic window; the maximum number of transmissions within each window of the periodic window; and the offset of the first window of the periodic window.

[0049] In an embodiment of the present application, the pseudo-periodic timing type or the pseudo-semi-persistent timing type may mean that the window for transmitting BFD-RS is periodic, but the resources within the window for transmitting BFD-RS are not fixed. Accordingly, the CSI-RS (or SSB) used as the BFD-RS may also be referred to as a pseudo-periodic CSI-RS (or SSB) or a pseudo-semi-persistent CSI-RS (or SSB).

[0050] Although the configuration information for pseudo-periodic BFD-RS and pseudo-semi-persistent BFD-RS may be the same, the difference between the two types lies in when the configuration information is considered valid by the UE. For example, for pseudo-periodic BFD-RS, once the UE receives the configuration information, the UE can assume that the configuration information is valid. That is, once the configuration information is received by the UE, the UE can assume that the BFD-RS is transmitted based on the configuration information. In contrast, for pseudo-semi-persistent BFD-RS, after receiving the configuration information, the UE may not assume that the BFD-RS is transmitted based on the configuration information until the configuration is activated. In the case of the Tx UE, the configuration can be activated by receiving an explicit activation message such as a Media Access Control (MAC) Control Element (CE) message or Downlink Control Information (DCI) from the BS. Alternatively, the Tx UE can determine to activate the configuration and transmit an explicit activation message such as a MAC CE or Sidelink Control Information (SCI) to the Rx UE. In the case of the Rx UE, the configuration can be activated by receiving an explicit activation message such as a MAC CE message or DCI from the BS. Alternatively, the configuration can be activated by receiving a MAC CE message or SCI from the Tx UE.

[0051] In an embodiment of the present application, the length of the periodic window can be defined as a parameter N, where N is a positive integer. The unit of N can be a time slot, millisecond, micro time slot, symbol, etc. For example, N can be expressed in terms of a time slot and one of the following values N ∈ {4, 5, 8, 10, 16, 20, 32, 40, 64, 80, 160, 320, 640} indicated in the configuration information.

[0052] In an embodiment of the present application, the offset of the first window of the periodic window can be defined as a parameter O, where O ∈ {0, 1,..., N - 1}. The unit of the parameter O can be the same as the unit of the parameter N. The reference point of the offset can be relative to the first time slot (i.e., time slot #0) of the first radio frame (i.e., radio frame #0 or RF#0). Alternatively, the reference point of the offset can be relative to the time of receiving an explicit activation message (such as a MAC CE message, DCI, or SCI).

[0053] In an embodiment of the present application, the timing type of BFD-RS can be indicated by a resourceType information element (IE). The RS type can be indicated by a new sl-BFD-RS-Type IE. The length of the periodic window can be indicated by a new sl-BFD-RS-LengthOfWindow IE. The minimum number of transmissions per window can be indicated by a new sl-BFD-RS-MinNumOfTxPerWindow IE. The maximum number of transmissions per window can be indicated by a new sl-BFD-RS-MaxNumOfTxPerWindow IE. The offset of the first window of the periodic window can be indicated by a new sl-BFD-RS-Offset IE.

[0054] For example, Table 1 below shows the IEs of sidelink (SL) BFD-RS that should be corrected or added to the 3GPP standard document.

[0055] Table 1: IEs of SL BFD-RS

[0056]

[0057]

[0058] After receiving the configuration for BFD-RS transmission, at step 302, the Tx UE (e.g., UE 101a) can transmit at least one transmission of BFD-RS on the sidelink within the periodic window according to the configuration information.

[0059] In some embodiments of the present application, the transmission may be subject to the availability of resources for at least one transmission of BFD-RS in the periodic window. For example, the periodic window can include a sequence of windows with the same periodicity or window length. In each window of the periodic window, whether the Tx UE will transmit at least one transmission of BFD-RS is subject to the availability of resources for at least one transmission of BFD-RS in each window of the periodic window. The resources for the transmission of BFD-RS can be obtained by at least one of the following: being autonomously selected by the Tx UE, being scheduled by the BS, and being determined and indicated by a UE other than the Tx UE.

[0060] After receiving the configuration for BFD-RS transmission, at step 402, the Rx UE can perform the reception of at least one transmission of BFD-RS on the sidelink within the periodic window according to the configuration information. At least one transmission of BFD-RS within the periodic window can be transmitted by the Tx UE (e.g., UE101a).

[0061] In some embodiments of the present application, the reception of at least one transmission performed in a periodic window may refer to an attempt to receive at least one transmission in the periodic window. However, for some reasons (e.g., the Tx UE does not transmit a BFD-RS transmission in a specific window of the periodic window, or the signal quality between the Tx UE and the Rx in a specific window of the periodic window is not good enough), the Rx UE may not receive at least one transmission in a specific window of the periodic window.

[0062] Figure 5 Illustrate an example of BFD-RS transmission in the time domain according to some embodiments of the present application.

[0063] Reference Figure 5 , the periodic window for BFD-RS transmission may be represented by W#0, W#1, W#2,..., and W#m, where m is a positive integer. Each window may have a window length of N time slots. The offset of the first window from time slot #0 of radio frame #0 is offset O. Within each window, the number of transmissions of BFD-RS may be greater than or equal to the minimum number of transmissions, and less than or equal to the maximum number of transmissions indicated in the configuration information. However, whether BFD-RS can be transmitted within a window is subject to the availability of resources for BFD-RS transmission within the window.

[0064] Reference Figure 5 , the Tx UE may transmit one transmission of BFD-RS within W#0, W#1, W#m-2, W#m-1, and W#m, because the minimum number of transmissions for SL BFD-RS within each window of the periodic window is set to 1. For W#2, no BFD-RS is transmitted within W#2 because there are no available resources for BFD-RS transmission. BFD-RS is transmitted twice by the Tx UE within W#3 because the maximum number of transmissions for SL BFD-RS within each window of the periodic window is set to 2. In an embodiment of the present application, the reason that BFD-RS is transmitted twice within a window may be that feedback from the Rx UE indicates an unsuccessful reception of the first transmission of BFD-RS.

[0065] The Rx UE may perform the reception of at least one transmission of BFD-RS within each window of the periodic window. However, performing the reception of at least one transmission does not mean receiving at least one transmission. For example, within W#2, the Rx UE may monitor the resources and attempt to receive at least one transmission of BFD-RS. However, since the Tx UE does not transmit BFD-RS within W#2, the Rx UE may not receive any transmission of BFD-RS. In another example, although the Tx UE may transmit at least one transmission of BFD-RS within a window, the Rx UE may still not receive any transmission of BFD-RS because the channel quality between the Tx UE and the Rx UE may not be good enough.

[0066] Figure 5 The periodic window in is illustrated as being continuously distributed in the time domain. According to some embodiments of the present application, this distribution can be regarded as the logical distribution of the periodic window. In practice, the physical distribution of the periodic window can be discontinuous depending on the distribution of the resource pool in the time domain. Additionally, according to some embodiments of the present application, discontinuous reception (DRX) can be supported. In these embodiments, the length and distribution of the DRX on-duration can be further defined within each window of the periodic window. The transmission / reception of BFD RS and the transmission / reception of BFD reports are performed during the DRX on-duration.

[0067] For example, Figure 6 illustrates another example of BFD-RS transmission in the time domain according to some other embodiments of the present application. In Figure 6 the example of Figure 6 , the logical distribution of the periodic window can be continuous, while the physical distribution of the periodic window can be discontinuous depending on the distribution of the resource pool in the time domain. Additionally, Figure 7 illustrates another example of BFD-RS transmission in the time domain according to some other embodiments of the present application. In Figure 7 the example of Figure 7 , each window of the periodic window can include a DRX on-duration period and a DRX off-duration period. The on-duration period can have a length. The transmission / reception of BFD-RS and the transmission / reception of BFD reports are performed during the DRX on-duration period.

[0068] According to some embodiments of the present application, BFD-RS is transmitted in the physical sidelink shared channel (PSSCH) transmission.

[0069] In an embodiment of the present application, each transmission of BFD-RS within the periodic window refers to transmitting a group of BFD-RS in one PSSCH transmission. The group of BFD-RS can include at least one BFD-RS.

[0070] In an embodiment of the present application, the Tx UE can transmit an indicator associated with the PSSCH transmission in the SCI to the Rx UE. The indicator can indicate the presence of BFD-RS in the PSSCH transmission. For the Rx UE, before receiving the PSSCH transmission, the RxUE can first receive the indicator associated with the PSSCH transmission in the SCI from the Tx UE. In response to receiving the indicator, the RxUE can assume that the PSSCH transmission includes BFD-RS. In response to not receiving the indicator, the Rx UE can assume that the PSSCH transmission does not include BFD-RS.

[0071] In another embodiment of the present application, BFD-RS may be transmitted in PSSCH transmission in response to all of the following three conditions being met: (1) the corresponding PSSCH is transmitted by the UE; (2) the SL BFD report is implemented by higher layer signaling; and (3) the corresponding SCI indicates the presence of BFD-RS.

[0072] According to some embodiments of the present application, resources in the frequency domain for transmitting BFD-RS may be defined by a set of sidelink physical resource blocks that include the sidelink BFD-RS to which the derived BFD report is related.

[0073] According to some embodiments of the present application, the configuration information may be transmitted in frequency range 1 (FR1) as specified in the 3GPP standard document. BFD-RS may be transmitted in FR2 as specified in the 3GPP standard document.

[0074] For the Rx UE, after receiving at least one transmission of BFD-RS within a periodic window, the Rx UE performs measurements and may report the BFD report according to the configuration for BFD reporting included in the configuration information. The BFD report may be determined based on the BFD-RS.

[0075] Accordingly, for the Tx UE, after transmitting at least one transmission of BFD-RS within a periodic window, the Tx UE may receive the BFD report according to the configuration for BFD reporting included in the configuration information.

[0076] The configuration for BFD reporting may indicate the reporting criterion. The reporting criterion may be one of pseudo-periodic reporting, pseudo-semi-persistent reporting, and event-triggered reporting.

[0077] According to some embodiments of the present application, in response to the reporting criterion being pseudo-periodic reporting or pseudo-semi-persistent reporting, the configuration for BFD reporting further indicates at least one of the following: the timing type of the BFD report; the periodicity of the BFD report; the reporting window of the BFD report; the number of BFD reports; and the maximum number of counters for unsuccessful reception of the BFD report.

[0078] In an embodiment of the present application, the timing type of the BFD report can be one of pseudo-periodic and pseudo-semi-persistent. Pseudo-periodic and pseudo-semi-persistent can mean that the reporting window of the BFD report is periodic, while the resources of the BFD report within each window are not fixed. The resources used for the BFD report within each window can be determined by the Rx UE. In the case where the timing type of the BFD report is pseudo-semi-persistent, the activation or deactivation of the configuration of the BFD report is determined based on the activation or deactivation of the configuration for BFD-RS transmission. For example, in response to the activation of the configuration for BFD-RS transmission, the configuration for the BFD report is activated. In response to the deactivation of the configuration for BFD-RS transmission, the configuration for the BFD report is deactivated.

[0079] In an embodiment of the present disclosure, the period is an integer multiple of the length of the periodic window for BFD-RS transmission. For example, the integer can be defined by the parameter m, where m is a positive integer. That is, for BFD-RS transmission, the BFD report can be triggered once every m windows.

[0080] In another embodiment of the present disclosure, the reporting window can be defined by a start point and an end point.

[0081] The reporting window can have a start point defined by one of the following: the start point of the (k*m - 1)-th window of the periodic window; the start point of the k*m-th window of the periodic window; and the time when the BRD-RS is received in the (k*m - 1)-th window of the periodic window, where k is a positive integer and k*m represents k multiplied by m.

[0082] The reporting window can have an end point defined by one of the following: the end point of the (k*m - 1)-th window of the periodic window; the end point of the k*m-th window of the periodic window; and the duration of the reporting window indicated in the configuration information, where k is a positive integer. In an embodiment of the present application, the duration of the reporting window can be indicated by the sl-LatencyBound-CSI-Report IE as specified in the 3GPP standard.

[0083] The start point can be combined with the end point or the duration to determine the reporting window. For example, the reporting window can have the start point of the (k*m - 1)-th window as the start point and the end point of the (k*m - 1)-th window as the end point. In this example, the length of the reporting window can be the length of each window of the periodic window.

[0084] In an embodiment of the present application, the reporting quantity can include at least one of the following: a first indicator indicating whether the beam pair is reliable for sidelink transmission; a channel quality indicator (CQI); a rank indicator (RI); a precoding matrix indicator (PMI); and a reference signal received power (RSRP).

[0085] In an embodiment of the present application, the timing type of the BFD report can be indicated by the new timingType of the sl-BFD-report IE. The periodicity of the BFD report can be indicated by the new sl-BFD-Report-Periodicity IE. The report window of the BFD report can be indicated by the new sl-BFD-Report-Window IE. The quantity of the BFD report can be indicated by the new sl-BFD-Report-Quantity IE.

[0086] For example, Table 2 below shows the IEs for pseudo-periodic reporting or pseudo-semi-persistent reporting that should be added to the 3GPP standard document.

[0087] Table 2: IEs for SL periodic reporting or pseudo-semi-persistent reporting

[0088]

[0089] In an embodiment of the present application, in response to unreliable sidelink transmissions indicated by the BFD report, the Rx UE can transmit an indication to the Tx UE to initiate a beam reselection procedure. Thereafter, the beam reselection procedure can be performed between the Tx UE and the Rx UE.

[0090] After receiving the configuration of the BFD report indicating the report window, the Rx UE can transmit the BFD report in the report window based on the configuration information. In an embodiment of the present application, the BFD report can be transmitted via at least one of the MAC CE message and the SCI. The resources for transmitting the BFD report can be obtained by at least one of the following: autonomously selected by the Rx UE, scheduled by the BS, and determined and indicated by a UE other than the Rx UE.

[0091] After receiving the configuration of the BFD report indicating the report window, the Tx UE can receive the BFD report in the report window based on the configuration information.

[0092] Figure 8 The figure illustrates an example of the BFD report in the time domain according to some embodiments of the present application.

[0093] Reference Figure 8 and the configuration of the periodic window for BFD-RS transmission can be the same as Figure 5 That is, the periodic window can be represented by W#0, W#1, W#2,..., and W#m, where m is a positive integer. Each window can have a window length of N time slots. The offset of the first window from time slot #0 of radio frame #0 is offset O.

[0094] The Tx UE can perform one transmission of the BFD-RS within W#0, W#1, W#m-2, W#m-1, and W#m. For W#2, since there are no available resources for BFD-RS transmission, the BFD-RS is not transmitted within W#2. For W#3, the BFD-RS is transmitted twice by the Tx within W#3.

[0095] In Figure 8 's example, a BFD report can be triggered every m windows. According to the above example, the reporting window can have one of the following starting points: the starting point of the (k*m - 1)-th window of the periodic window; the starting point of the (k*m)-th window of the periodic window; and the time when the BFD-RS is received in the (k*m - 1)-th window of the periodic window, where k is a positive integer.

[0096] For simplicity, Figure 8 's example only shows the case where k = 1. That is, as Figure 8 shows, Case 1 shows that the reporting window can use the starting point of window W#m-1 as the starting point of the reporting window. Case 2 shows that the reporting window can use the starting point of window W#m as the starting point of the reporting window. Case 3 shows that the reporting window can use the time when the BFD-RS is received in window W#m-1 as the starting point of the reporting window. The lengths of the reporting windows for the three cases can be the same.

[0097] As Figure 8 shows, the Rx UE can transmit a BFD report to the Tx UE within the reporting window of Case 3. Although Figure 5 shows the transmission of the BFD report within the reporting window determined based on window W#m-1, those skilled in the art can understand that a BFD report can be transmitted every m windows, that is, within the periodic reporting window determined based on window W#k*m-1.

[0098] Pseudo-periodic or pseudo-semi-persistent BFD reports can be used to initiate the beam failure recovery procedure.

[0099] For the Rx UE, initiating the beam failure recovery procedure can include the following four steps.

[0100] Step 1: The Rx UE can first initialize the counter for unsuccessful reception of the BFD report to zero.

[0101] Step 2: When the reporting window is triggered, the Rx UE can attempt to transmit a BFD report within the reporting window.

[0102] Step 3: In response to transmitting a BFD report in the reporting window, the Rx UE may attempt to receive a second indicator indicating whether the BFD report has been successfully received. In an embodiment of the present application, the indicator may be transmitted together with the BFD-RS transmission in the next window for BFD-RS transmission adjacent to the reporting window. In another embodiment of the present application, the indicator may be an acknowledgement (ACK) indicator or a non-acknowledgement (NACK) indicator.

[0103] In response to the successful reception of the BFD report indicated by the second indicator, the Rx UE may perform Step 4, that is, normally perform BFD-RS reception and measurement.

[0104] In response to the unsuccessful reception of the BFD report indicated by the second indicator, the Rx UE may increment a counter by 1. In response to reaching the maximum number of the counter, the Rx UE may trigger a beam failure recovery window and transmit an indication for initiating a beam failure recovery procedure to the Tx UE. In an embodiment of the present application, the indication for initiating a beam failure recovery procedure may be transmitted in FR1 as specified in the 3GPP standard document. Otherwise, the Rx UE may trigger a new reporting window and return to Step 2.

[0105] Step 4: The Rx UE normally performs BFD-RS reception and measurement.

[0106] For the Tx UE, initiating a beam failure recovery procedure may include the following four steps.

[0107] Step 1: The Tx UE may first initialize a counter for the unsuccessful reception of the BFD report to zero.

[0108] Step 2: When the reporting window is triggered, the Tx UE may attempt to receive the BFD report in the reporting window.

[0109] Step 3: In response to the unsuccessful reception or successful reception of the BFD report in the reporting window, the Tx UE may transmit a second indicator indicating whether the BFD report has been successfully received. In an embodiment of the present application, the indicator may be transmitted together with the BFD-RS transmission in the next window for BFD-RS transmission adjacent to the reporting window. In another embodiment of the present application, the indicator may be an ACK indicator or a NACK indicator.

[0110] In response to the successful reception of the BFD report indicated by the second indicator, the Tx UE may perform Step 4, that is, normally perform BFD-RS transmission.

[0111] In response to the unsuccessful reception of the BFD report indicated by the second indicator, the Tx UE may increment a counter by 1. In response to reaching the maximum number of the counter, the Tx UE may trigger a beam failure recovery window and receive an indication for initiating a beam failure recovery procedure from the Rx UE. In an embodiment of the present application, an indication for initiating a beam failure recovery procedure may be received in FR1. Otherwise, the Tx UE may trigger a new reporting window and return to step 2.

[0112] Step 4: The Tx UE normally performs BFD-RS transmission.

[0113] Figure 9 Illustrates an example of initiating a beam failure recovery procedure according to some embodiments of the present application.

[0114] Reference Figure 9 , the periodic window may be represented by W#0,..., W#m-1, W#m, W#m+1, W#m+2, and W#m+3, where m is a positive integer. The Rx UE may perform reception of at least one transmission of BFD-RS within each window of the periodic window.

[0115] Figure 9 The reporting window in may use the time of receiving the BFD-RD transmission as a starting point and have a fixed duration. For example, the first reporting window starts from the time of receiving the BFD-RD transmission in W#m-1. The first reporting window may have a fixed duration such that the end point of the first reporting window is within window W#m. A counter for unsuccessful reception of the BFD report is set to zero. In the first reporting window, the Rx UE may transmit a BFD report to the Tx UE. If the BFD report is not successfully received by the Tx UE, then at the next window adjacent to the first reporting window (i.e., W#m+1), the Tx UE may transmit a NACK indicator indicating the unsuccessful reception of the BFD report. The NACK indicator may be transmitted together with the BFD-RS transmission that triggers the second reporting window. That is, the second reporting window starts from the time of receiving the BFD-RD transmission in W#m+1. The second reporting window may have a fixed duration such that the end point of the second reporting window is within window W#m+2. The counter for unsuccessful reception of the BFD report is incremented by 1 and equals 1.

[0116] In the second reporting window, the Rx UE may transmit a BFD report to the Tx UE. If the BFD report is not successfully received by the Tx UE, then at the next window adjacent to the second reporting window (i.e., W#m+3), the Tx UE may transmit a NACK indicator indicating the unsuccessful reception of the BFD report. The NACK indicator may be transmitted together with the BFD-RS transmission.

[0117] In Figure 9In an example, the maximum number of counters for unsuccessfully received BFD reports may be 2. Therefore, after receiving a NACK indicator in W#m+3, the counter for unsuccessfully received BFD reports is incremented by 1 and equals 2. Therefore, the Rx UE may trigger a beam failure recovery window and transmit an indication to the Tx UE to initiate a beam failure recovery procedure.

[0118] According to some other embodiments of the present application, in response to the reporting criterion indicated by the configuration for BFD reports being event-triggered reporting, the configuration for reporting may further indicate at least one of the following: the identity (ID) of the event; the value of the beam failure instance (BFI) timer; the maximum number of BFI indications; and the threshold for BFI. In an embodiment of the present application, the threshold may be mapped to a 10% block error rate (BLER) of a hypothetical physical sidelink control channel (PSCCH).

[0119] In an embodiment of the present application, the value of the BFI timer and the maximum number of BFI indications are associated with at least one of a geographical zone, a resource pool, and the quality of service (QoS) of traffic in the sidelink.

[0120] In an embodiment of the present application, the value of the BFI timer may be an integer multiple of the length of a periodic window.

[0121] In an embodiment of the present application, the ID of the event may be indicated by a new sl-BFD-Report-EventId IE. The value of the BFI timer (expressed, for example, in terms of the number of windows for BFD-RS transmission) may be indicated by a new sl-BFD-Report-BFITimerInNumOfWindow IE. The maximum number of BFI indications may be indicated by a new sl-BFD-Report-MaxNumOfBFIforBeamReselection IE. The threshold for BFI may be indicated by a new sl-BFD-Report-ThresholdForBeamReselection IE.

[0122] For example, Table 3 below shows the IEs for event-triggered reporting that should be added to the 3GPP standard document.

[0123] Table 3: IEs for event-triggered reporting

[0124]

[0125] For the Rx UE, after receiving the configuration of the BFD report indicating the triggering of an event, the Rx UE may implement the BFI timer for the sidelink. Once the BFI counter is incremented by 1, the BFI timer can be restarted. Additionally, the media access control (MAC) layer of the Rx UE may implement the BFI counter for the sidelink to count the BFI indications.

[0126] The Rx UE may first initialize the BFI counter to zero. Within the window of a periodic window, after receiving a transmission containing a set of BFD-RSs, the Rx UE may compare the signal quality of each BFD-RS in the set of BFD-RSs associated with the transmission of the BFD-RSs with the threshold indicated in the configuration information. In response to all signal qualities of the set of BFD-RSs being lower than the threshold, the physical layer may transmit a BFI indication to the MAC layer. According to some embodiments of the present application, the window of the periodic window may include more than one transmission, and as long as the signal quality of one transmission within the window is greater than the threshold, the Rx UE may not transmit a BFI indication to the MAC layer.

[0127] After receiving the BFI indication, the MAC layer of the Rx UE may restart the BFI timer and increment the BFI counter by 1. In an embodiment of the present application, in response to the expiration of the BFI timer, the UE may reset the BFI counter to zero. In an embodiment of the present application, in response to the BFI counter reaching the maximum number, the Rx UE may transmit an indication to the Tx UE to initiate a beam reselection procedure.

[0128] For example, Figure 10 illustrates an example of detecting an event of a beam reselection procedure according to some embodiments of the present application.

[0129] Refer to Figure 10 , the periodic window for BFD-RS transmission may be represented by W#0, W#1, W#2,..., and W#m, where m is a positive integer. The value of the BFI timer is equal to 4 windows of the periodic window. Within W#0, there is one transmission containing a set of BFD-RSs. The Rx may determine that the signal quality of at least one BFD-RS in the set of BFD-RSs is higher than the threshold, and then maintain the BFI counter at 0. Within W#1, there is one transmission containing a set of BFD-RSs. The Rx may determine that all signal qualities of the set of BFD-RSs are lower than the threshold, and then increment the BFI counter by 1 and make it equal to 1 and restart the BFI timer. Within W#2, there is no transmission, and thus the Rx may determine that all signal qualities of the set of BFD-RSs are lower than the threshold, and then increment the BFI counter by 1 and make it equal to 2 and restart the BFI timer.

[0130] Within W#3, there are two BFD-RS transmissions, and each transmission may include a set of BFD-RS. For the first transmission, the Rx may determine that the signal quality of all the BFD-RS in the set is lower than the threshold. For the second transmission, the Rx may determine that the signal quality of at least one BFD-RS in the set is higher than the threshold. Therefore, within W#3, the BFI counter does not increment by 1 and remains equal to 2. For each window, the Rx UE may perform the above operations. Once the BFI timer expires, the BFI counter is reset to zero. In Figure 10 In an example of, within W#m, the Rx may determine that the signal quality of all the BFD-RS in the set is lower than the threshold, and then increment the BFI counter by 1 and may reach the maximum number indicated by BFI. In response to the BFI counter reaching the maximum number, the Rx UE may detect an event of the beam reselection procedure, and thus the Rx UE may transmit an indication to initiate the beam reselection procedure.

[0131] For the Tx UE, after receiving the configuration of the BFD report indicating the event trigger, in the case where the Rx UE detects an event for the beam reselection procedure, the Tx UE may receive an indication from the Rx UE to initiate the beam reselection procedure. Thereafter, the beam reselection procedure may be performed between the Tx UE and the Rx UE. The specific procedure is illustrated in Figure 11 FIG.

[0132] Figure 11 FIG. illustrates an example of initiating a beam reselection procedure according to some embodiments of the present application.

[0133] Referring to Figure 11 , at step 1101, the Rx UE may detect an event of the beam reselection procedure. For example, as shown in Figure 10 , the event may be detected in response to the BFI counter reaching the maximum number. In response to detecting the event, at step 1102, the Rx UE may transmit an indication to the Tx UE to initiate the beam reselection procedure. At step 1103, the beam reselection procedure may be performed between the Tx UE and the Rx UE. In an embodiment of the present application, the indication may be transmitted in FR2 as specified in the 3GPP standard document. In an embodiment of the present application, the beam reselection procedure may be performed in FR2 as specified in the 3GPP standard document.

[0134] Figure 12 FIG. illustrates a simplified block diagram of an apparatus 1200 for beam failure detection and recovery in a sidelink according to some embodiments of the present application. The apparatus 1200 may be the BS 102 or the UE 101 (e.g., UE101a or UE 101b) as shown in Figure 1 .

[0135] Referring toFigure 12 , the apparatus 1200 may include at least one non-transitory computer-readable medium 1202, at least one receiving circuit 1204, at least one transmitting circuit 1206, and at least one processor 1208. In some embodiments of the present application, the at least one receiving circuit 1204 and the at least one transmitting circuit 1206 may be integrated into at least one transceiver. The at least one non-transitory computer-readable medium 1202 may have computer-executable instructions stored therein. The at least one processor 1208 may be coupled to the at least one non-transitory computer-readable medium 1202, the at least one receiving circuit 1204, and the at least one transmitting circuit 1206. The computer-executable instructions may be programmed to implement a method using the at least one receiving circuit 1204, the at least one transmitting circuit 1206, and the at least one processor 1208. The method may be a method according to an embodiment of the present application, such as Figure 3 or Figure 4 the method shown in

[0136] The method according to an embodiment of the present application may also be implemented on a programmed processor. However, the controller, flowchart, and module may also be implemented on a general-purpose or special-purpose computer, a programmed microprocessor or microcontroller, and peripheral integrated circuit elements, integrated circuits, hardware electronic or logic circuits (such as discrete element circuits), programmable logic devices, etc. Generally, any device on which a finite state machine capable of implementing the flowchart shown in the figure resides may be used to implement the processor function of the present application. For example, an embodiment of the present application provides a device for emotion recognition from speech, which includes a processor and a memory. Computer-programmable instructions for implementing a method for emotion recognition from speech are stored in the memory, and the processor is configured to execute the computer-programmable instructions to implement a method for emotion recognition from speech. The method may be the method as described above or other methods according to an embodiment of the present application.

[0137] Alternative embodiments preferably implement the methods of embodiments of the present application in a non - transitory computer - readable storage medium storing computer - programmable instructions. The instructions are preferably executed by a computer - executable component preferably integrated with a network security system. The non - transitory computer - readable storage medium can be stored on any suitable computer - readable medium, such as RAM, ROM, flash memory, EEPROM, optical storage devices (CD or DVD), hard disk drives, floppy disk drives, or any suitable device. The computer - executable component is preferably a processor, but the instructions can alternatively or additionally be executed by any suitable dedicated hardware device. For example, embodiments of the present application provide a non - transitory computer - readable storage medium storing computer - programmable instructions. The computer - programmable instructions are configured to implement the method for emotion recognition from speech as described above or other methods according to embodiments of the present application.

[0138] Although the present application has been described in its specific embodiments, it is obvious that many alternatives, modifications, and variations will be apparent to those skilled in the art. For example, in other embodiments, various components of the embodiments can be interchanged, added, or replaced. Also, not all elements of every figure are necessary for the operation of the disclosed embodiments. For example, those skilled in the art of the disclosed embodiments will be able to make and use the teachings of the present application by simply adopting the elements of the independent technical solutions. Therefore, the embodiments of the present application as set forth herein are intended to be illustrative rather than restrictive. Various changes can be made without departing from the spirit and scope of the present application.

Claims

1. A device for wireless communication, comprising: a receiver; a transmitter; a processor coupled to the receiver and the transmitter and configured to cause the device to: obtain configuration information for a beam failure recovery (BFR) procedure on a sidelink, the configuration information indicating a periodic window; and receive at least one transmission of a beam failure detection reference signal (BFD-RS) on the sidelink within the periodic window according to the configuration information; wherein the configuration information further indicates reporting criteria for a BFD report, and wherein the reporting criteria is one of a pseudo-periodic report, a pseudo-semi-persistent report, or an event-triggered report.

2. The device according to claim 1, wherein the configuration information further indicates at least one of the following: a timing type of the BFD-RS, the timing type being one of pseudo-periodic or pseudo-semi-persistent; an RS type of the BFD-RS, the RS type being one of a synchronization signal and a physical broadcast channel (PBCH) block (SSB) or a channel state information (CSI) reference signal (CSI-RS); a length of the periodic window; a minimum number of transmissions within each window of the periodic window; a maximum number of transmissions within each window of the periodic window; or an offset of a first window of the periodic window.

3. The device according to claim 1, wherein for the reporting criteria being the pseudo-periodic report or the pseudo-semi-persistent report, the configuration information further indicates at least one of the following: a timing type of the BFD report; a periodicity of the BFD report; a reporting window of the BFD report; a quantity of the BFD report; or a maximum number of a counter for unsuccessful reception of the BFD report.

4. The device according to claim 3, wherein the quantity comprises at least one of the following: a first indicator indicating whether a beam pair is reliable for sidelink transmission; a channel quality indicator (CQI); a rank indicator (RI); a precoding matrix indicator (PMI); or a reference signal received power (RSRP).

5. The device according to claim 3, wherein the processor coupled to the receiver and the transmitter is configured to cause the device to transmit the BFD report in the reporting window based on the configuration information.

6. The device according to claim 3, wherein in response to an unreliable sidelink transmission indicated by the BFD report, the processor coupled to the receiver and the transmitter is configured to cause the device to transmit an indication to initiate a beam reselection procedure.

7. The device according to claim 1, wherein in response to the reporting criteria being the event-triggered report, the configuration information further indicates at least one of the following: a value of a beam failure instance (BFI) timer; a maximum number of BFI indications; or a threshold for the BFI.

8. The device according to claim 7, wherein the processor coupled to the receiver and the transmitter is configured to cause the device to: Compare the signal quality of each BFD-RS in a set of BFD-RSs associated with each transmission of the BFD-RS with the threshold; and In response to all of the signal qualities of the set of BFD-RSs being below the threshold, restart the BFI timer and increment the BFI counter by 1.

9. The apparatus according to claim 8, wherein in response to the BFI counter reaching the maximum number, the processor coupled to the receiver and the transmitter is configured to cause the apparatus to transmit an indication to initiate a beam reselection procedure.

10. An apparatus for wireless communication, comprising:[[]] A receiver; A transmitter; A processor coupled to the receiver and the transmitter and configured to cause the apparatus to:[[]] Obtain configuration information for a beam failure recovery BFR procedure on a sidelink, the configuration information indicating a periodic window; and In accordance with the configuration information, transmit at least one transmission of a beam failure detection reference signal BFD-RS on the sidelink within the periodic window; Wherein the configuration information further indicates reporting criteria for BFD reporting, and wherein the reporting criteria is one of pseudo-periodic reporting, pseudo-semi-persistent reporting, or event-triggered reporting.

11. The apparatus according to claim 10, wherein the configuration information further indicates at least one of the following:[[]] The timing type of the BFD-RS, the timing type being one of pseudo-periodic or pseudo-semi-persistent; The RS type of the BFD-RS, the RS type being one of a synchronization signal and a physical broadcast channel PBCH block SSB or a channel state information CSI reference signal CSI-RS; The length of the periodic window; The minimum number of transmissions within each window of the periodic window; The maximum number of transmissions within each window of the periodic window; or The offset of the first window of the periodic window.

12. The apparatus according to claim 10, wherein the processor coupled to the receiver and the transmitter is configured to cause the apparatus to transmit a media access control MAC control element CE message or sidelink control information SCI to activate the configuration information.

13. The apparatus according to claim 10, wherein for the reporting criteria being the pseudo-periodic reporting or the pseudo-semi-persistent reporting, the configuration information further indicates at least one of the following:[[]] The timing type of the BFD reporting; The periodicity of the BFD reporting; The reporting window of the BFD reporting; The number of the BFD reporting; or The maximum number of a counter for unsuccessful reception of the BFD reporting.

14. The apparatus according to claim 13, wherein the number includes at least one of the following:[[]] A first indicator indicating whether a beam pair is reliable for sidelink transmission; A channel quality indicator CQI; A rank indicator RI; A precoding matrix indicator PMI; Or A reference signal received power RSRP.

15. The apparatus according to claim 13, wherein the processor coupled to the receiver and the transmitter is configured to cause the apparatus to receive the BFD report in the reporting window based on the configuration information.

16. The apparatus according to claim 13, wherein in response to an unreliable sidelink transmission indicated by the BFD report, the processor coupled to the receiver and the transmitter is configured to cause the apparatus to receive an indication to initiate a beam reselection procedure.

17. The apparatus according to claim 10, wherein the processor coupled to the receiver and the transmitter is configured to cause the apparatus to receive an indication to initiate a beam reselection procedure.

18. An apparatus for wireless communication, comprising: a receiver; a transmitter; a processor coupled to the receiver and the transmitter and configured to cause the apparatus to: transmit configuration information for a beam failure recovery (BFR) procedure on a sidelink, the configuration information indicating a periodic window within which at least one transmission of a beam failure detection reference signal (BFD-RS) occurs according to the configuration information; and the configuration information further indicates at least one of the following: a timing type of the BFD-RS, the timing type being one of pseudo-periodic or pseudo-semi-persistent; an RS type of the BFD-RS, the RS type being one of a synchronization signal and a physical broadcast channel (PBCH) block (SSB) or a channel state information (CSI) reference signal (CSI-RS); a length of the periodic window; a minimum number of transmissions within each window of the periodic window; a maximum number of transmissions within each window of the periodic window; or an offset of a first window of the periodic window; wherein the configuration information further indicates reporting criteria for a BFD report, and wherein the reporting criteria is one of pseudo-periodic reporting, pseudo-semi-persistent reporting, or event-triggered reporting.

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