Method for switching to backup beam technique

Abstract

Methods, systems, and devices for wireless communications are described. A wireless device may communicate via a primary beam and a backup beam. To support communications via the primary beam and the backup beam, a preconfiguration process may be performed to communicate identification of the primary beam and the backup beam to a transmitting and receiving device. A central scheduling node may assist in identifying the primary beam and the backup beam for the transmitting and receiving device. During communications, when an initial communication fails, the transmitting and receiving device may switch to the backup beam, and a retransmission including data from the initial communication may be performed via the backup beam.

Description

[0001] Cross-references

[0002] This patent application claims priority to U.S. patent application No. 16 / 926,899, filed on July 13, 2020 by GUPTA et al., entitled “TECHNIQUES FOR SWITCHING TO FALLBACK TEAM,” which claims the benefit of U.S. Provisional Patent Application No. 62 / 886,231, filed on August 13, 2019 by GUPTA et al., entitled “TECHNIQUES FOR SWITCHING TO FALLBACKBEAM,” both of which are assigned to the present assignee. Technical Field

[0003] The following relates generally to wireless communications, and more particularly to switching to a fallback beam. Background Art

[0004] Wireless communication systems are widely deployed to provide various types of communication content, such as voice, video, packet data, messaging, broadcast, etc. These systems can support communication with multiple users by sharing available system resources (e.g., time, frequency, and power). Examples of such multiple access systems include fourth generation (4G) systems, such as long term evolution (LTE) systems, LTE advanced (LTE-A) systems, or LTE-A Pro systems, and fifth generation (5G) systems (which may be referred to as new radio (NR) systems). These systems may use techniques such as code division multiple access (CDMA), time division multiple access (TDMA), frequency division multiple access (FDMA), orthogonal frequency division multiple access (OFDMA), or discrete Fourier transform spread orthogonal frequency division multiplexing (DFT-S-OFDM). A wireless multiple access communication system may include multiple base stations or network access nodes, each of which simultaneously supports communication with multiple communication devices, which may be referred to as user equipment (UE).

[0005] Wireless communication systems may use ultra-reliable low-latency communication (URLLC) techniques to exchange data between wireless devices -- for example, if the wireless devices are in an operationally or safety-critical environment, such as a manufacturing facility or autonomous vehicle application. Techniques for increasing the reliability and reducing latency of communications between wireless devices in operationally critical environments may be desirable. Summary of the invention

[0006] The present disclosure relates to improved techniques for supporting switching to backup beams. In order to increase the reliability and latency metrics of communications between devices, the transmitting and receiving devices may pre-configure primary and backup transmit beams for subsequent coordinated switching between the primary and backup transmit beams after a first transmission of user data fails.

[0007] A method for wireless communication at a UE is described. The method may include receiving a set of transmit beams, reporting CSI for the set of transmit beams, receiving an indication of a first transmit beam in the set of transmit beams based on the reported CSI, wherein the first transmit beam is configured to transmit an initial transmission to the UE, identifying a second transmit beam in the set of transmit beams, wherein the second transmit beam is configured to transmit a retransmission to the UE, failing to receive or decode a first transmission of user data via the first transmit beam during a first interval, sending a negative acknowledgement (NACK) message based on failing to receive or decode the first transmission, and receiving a second transmission of user data via the second transmit beam during a subsequent interval.

[0008] An apparatus for wireless communication at a UE is described. The apparatus may include a processor, a memory coupled to the processor, and instructions stored in the memory. The instructions may be executable by the processor to cause the apparatus to receive a set of transmit beams, report CSI for the set of transmit beams, receive an indication of a first transmit beam in the set of transmit beams based on the reported CSI, wherein the first transmit beam is configured to transmit an initial transmission to the UE, identify a second transmit beam in the set of transmit beams, wherein the second transmit beam is configured to transmit a retransmission to the UE, fail to receive or decode a first transmission of user data via the first transmit beam during a first interval, send a negative acknowledgement (NACK) message based on the failure to receive or decode the first transmission, and receive a second transmission of user data via the second transmit beam during a subsequent interval.

[0009] Another apparatus for wireless communication at a UE is described. The apparatus may include means for receiving a set of transmit beams, means for reporting CSI for the set of transmit beams, means for receiving an indication of a first transmit beam in the set of transmit beams based on the reported CSI, wherein the first transmit beam is configured to transmit an initial transmission to the UE, means for identifying a second transmit beam in the set of transmit beams, wherein the second transmit beam is configured to transmit a retransmission to the UE, means for failing to receive or decode a first transmission of user data via the first transmit beam during a first interval, means for sending a negative acknowledgement (NACK) message based on failing to receive or decode the first transmission, and means for receiving a second transmission of user data via the second transmit beam during a subsequent interval.

[0010] A non-transitory computer-readable medium storing code for wireless communication at a UE is described. The code may include instructions executable by a processor to: receive a set of transmit beams, report CSI for the set of transmit beams, receive an indication of a first transmit beam in the set of transmit beams based on the reported CSI, wherein the first transmit beam is configured to transmit an initial transmission to the UE, identify a second transmit beam in the set of transmit beams, wherein the second transmit beam is configured to transmit a retransmission to the UE, fail to receive or decode a first transmission of user data via the first transmit beam during a first interval, send a negative acknowledgement (NACK) message based on the failure to receive or decode the first transmission, and receive a second transmission of user data via the second transmit beam during a subsequent interval.

[0011] Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may further include operations, features, components, or instructions for switching from a first receive beam corresponding to the first transmit beam to a second receive beam corresponding to the second transmit beam based on sending a NACK message.

[0012] Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may further include operations, features, components, or instructions for receiving an indication of a set of periodic intervals during which the UE may be scheduled to receive an initial transmission of user data, wherein the set of periodic intervals includes a first interval.

[0013] In some examples of the methods, apparatus, and non-transitory computer-readable media described herein, receiving a second transmission of user data during a subsequent interval may include operations, features, components, or instructions for receiving control information in a control channel indicating a location of the user data in a data channel.

[0014] In some examples of the methods, apparatus, and non-transitory computer-readable media described herein, a spatial diversity between the first transmit beam and the second transmit beam exceeds a threshold.

[0015] In some examples of the methods, apparatus, and non-transitory computer-readable media described herein, the indication indicates a second transmit beam.

[0016] In some examples of the methods, apparatus, and non-transitory computer-readable media described herein, receiving an indication of a first transmit beam includes receiving a control message that includes a first field for indicating the first transmit beam for the first transmission and a second field for indicating a second transmit beam for the second transmission.

[0017] In some examples of the methods, apparatus, and non-transitory computer-readable media described herein, identifying the second transmit beam includes determining a mapping between the first transmit beam and the second transmit beam based on a table.

[0018] A method for wireless communication at a wireless device is described. The method may include transmitting a set of transmit beams, receiving CSI for the set of transmit beams, the CSI including CSI reported by a UE, identifying a first transmit beam and a second transmit beam in the set of transmit beams based on the CSI, sending an indication of the first transmit beam to the UE based on the reported CSI, wherein the first transmit beam is configured to transmit an initial transmission to the UE and the second transmit beam is configured to transmit a retransmission to the UE, during a first interval, transmitting a first transmission of user data to the UE via the first transmit beam, failing to receive or decode an acknowledgment (ACK) message in response to the first transmission, and during a subsequent interval, based on failing to receive or decode the ACK message, transmitting a second transmission of user data to the UE via the second transmit beam.

[0019] An apparatus for wireless communication at a wireless device is described. The apparatus may include a processor, a memory coupled to the processor, and instructions stored in the memory. The instructions may be executed by the processor to cause the apparatus to transmit a set of transmit beams, receive CSI of the set of transmit beams, the CSI including CSI reported by a UE, identify a first transmit beam and a second transmit beam in the set of transmit beams based on the CSI, send an indication of the first transmit beam to the UE based on the reported CSI, wherein the first transmit beam is configured to transmit an initial transmission to the UE, and the second transmit beam is configured to transmit a retransmission to the UE, during a first interval, send a first transmission of user data to the UE via the first transmit beam, fail to receive or decode an acknowledgment (ACK) message in response to the first transmission, and during a subsequent interval, based on the failure to receive or decode the ACK message, send a second transmission of user data to the UE via the second transmit beam.

[0020] Another apparatus for wireless communication at a wireless device is described. The apparatus may include means for transmitting a set of transmit beams, means for receiving CSI for the set of transmit beams, the CSI including CSI reported by a UE, means for identifying a first transmit beam and a second transmit beam in the set of transmit beams based on the CSI, means for transmitting an indication of the first transmit beam to the UE based on the reported CSI, wherein the first transmit beam is configured to transmit an initial transmission to the UE and the second transmit beam is configured to transmit a retransmission to the UE, means for transmitting a first transmission of user data to the UE via the first transmit beam during a first interval, means for failing to receive or decode an acknowledgment (ACK) message in response to the first transmission, and means for transmitting a second transmission of user data to the UE via the second transmit beam during a subsequent interval based on failing to receive or decode the ACK message.

[0021] A non-transitory computer-readable medium storing code for wireless communication at a wireless device is described. The code may include instructions executable by a processor to transmit a set of transmit beams, receive CSI for the set of transmit beams, the CSI including CSI reported by a UE, identify a first transmit beam and a second transmit beam in the set of transmit beams based on the CSI, send an indication of the first transmit beam to the UE based on the reported CSI, wherein the first transmit beam is configured to transmit an initial transmission to the UE and the second transmit beam is configured to transmit a retransmission to the UE, during a first interval, send a first transmission of user data to the UE via the first transmit beam, fail to receive or decode an acknowledgment (ACK) message in response to the first transmission, and during a subsequent interval, based on the failure to receive or decode the ACK message, send a second transmission of user data to the UE via the second transmit beam.

[0022] In some examples of the methods, apparatus, and non-transitory computer-readable media described herein, sending the transmit beam set may include operations, features, components, or instructions for sending a first transmit beam from a first transmit / receive point (TRP) and sending a second transmit beam from a second TRP.

[0023] Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may further include operations, features, components, or instructions for calculating a set of spatial diversity values ​​between transmit beams of the set of transmit beams, and selecting the first transmit beam and the second transmit beam based on determining that the spatial diversity value calculated between the first transmit beam and the second transmit beam exceeds a threshold.

[0024] Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may further include operations, features, components, or instructions for calculating a set of channel quality values ​​for the transmit beam set based on the CSI reported by the UE, wherein calculating the set of spatial diversity values ​​includes calculating the set of spatial diversity values ​​between transmit beams of a subset of the transmit beam set having channel quality values ​​exceeding a second threshold, wherein the subset of the transmit beam set includes a first transmit beam and a second transmit beam.

[0025] In some examples of the methods, apparatus, and non-transitory computer-readable media described herein, the CSI may include operations, features, components, or instructions for sending a second indication of a first transmit beam and a second transmit beam to a second UE based on the reported CSI, wherein the first transmit beam may be configured to transmit an initial transmission from the second UE to the UE, and the second transmit beam may be configured to transmit a retransmission from the second UE to the UE.

[0026] In some examples of the methods, apparatus, and non-transitory computer-readable media described herein, receiving CSI may include operations, features, components, or instructions for receiving CSI reported by a UE from a base station.

[0027] In some examples of the methods, apparatus, and non-transitory computer-readable media described herein, identifying the first transmit beam and the second transmit beam may include operations, features, components, or instructions for receiving an indication of the first transmit beam and the second transmit beam from a base station.

[0028] Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may further include operations, features, components, or instructions for receiving an indication of a set of periodic intervals during which the UE may be scheduled to send an initial transmission of user data, wherein the set of periodic intervals includes a first interval.

[0029] In some examples of the methods, apparatus, and non-transitory computer-readable media described herein, sending a second transmission of user data during a subsequent interval may include operations, features, components, or instructions for sending control information in a control channel indicating a location of the user data in a data channel.

[0030] In some examples of the methods, apparatus, and non-transitory computer-readable media described herein, a spatial diversity between the first transmit beam and the second transmit beam exceeds a threshold.

[0031] In some examples of the methods, apparatus, and non-transitory computer-readable media described herein, the indication indicates a second transmit beam.

[0032] Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may further include operations, features, components, or instructions for generating a table for providing a mapping between a main transmit beam and a backup transmit beam based on CSI, and sending the table to a UE, wherein the table includes a mapping between a first transmit beam and a second transmit beam.

[0033] A method for wireless communication at a first UE is described. The method may include transmitting a set of transmit beams, receiving an indication of a first transmit beam in the set of transmit beams from a base station based on CSI reported by a second UE to the base station, wherein the first transmit beam is configured to transmit an initial transmission from the first UE to the second UE; identifying a second transmit beam in the set of transmit beams based on the indication, wherein the second transmit beam is configured to transmit a retransmission from the first UE to the second UE, during a first interval, transmitting a first transmission of user data to the second UE via the first transmit beam, failing to receive or decode an acknowledgement (ACK) message in response to the first transmission, and during a subsequent interval, transmitting a second transmission of user data to the second UE via the second transmit beam based on failing to receive or decode the ACK message.

[0034] A device for wireless communication at a first UE is described. The device may include a processor, a memory coupled to the processor, and instructions stored in the memory. The instructions may be executed by the processor to cause the device to transmit a set of transmit beams, receive an indication of a first transmit beam in the set of transmit beams from a base station based on CSI reported by a second UE to the base station, wherein the first transmit beam is configured to transmit an initial transmission from the first UE to the second UE; identify a second transmit beam in the set of transmit beams based on the indication, wherein the second transmit beam is configured to transmit a retransmission from the first UE to the second UE, during a first interval, transmit a first transmission of user data to the second UE via the first transmit beam, fail to receive or decode an acknowledgment (ACK) message in response to the first transmission, and during a subsequent interval, based on the failure to receive or decode the ACK message, transmit a second transmission of user data to the second UE via the second transmit beam.

[0035] Another apparatus for wireless communication at a first UE is described. The apparatus may include means for transmitting a set of transmit beams, means for receiving an indication of a first transmit beam in the set of transmit beams from a base station based on CSI reported by a second UE to the base station, wherein the first transmit beam is configured to transmit an initial transmission from the first UE to the second UE; identifying a second transmit beam in the set of transmit beams based on the indication, wherein the second transmit beam is configured to transmit a retransmission from the first UE to the second UE, means for transmitting a first transmission of user data to the second UE via the first transmit beam during a first interval, means for failing to receive or decode an acknowledgment (ACK) message in response to the first transmission, and means for transmitting a second transmission of user data to the second UE on the second transmit beam during a subsequent interval based on failing to receive or decode the ACK message.

[0036] A non-transitory computer-readable medium storing code for wireless communication at a first UE is described. The code may include instructions executable by a processor to transmit a set of transmit beams, receive an indication of a first transmit beam in the set of transmit beams from a base station based on CSI reported by a second UE to the base station, wherein the first transmit beam is configured to transmit an initial transmission from the first UE to the second UE; identify a second transmit beam in the set of transmit beams based on the indication, wherein the second transmit beam is configured to transmit a retransmission from the first UE to the second UE, during a first interval, transmit a first transmission of user data to the second UE via the first transmit beam, fail to receive or decode an acknowledgment (ACK) message in response to the first transmission, and during a subsequent interval, based on the failure to receive or decode the ACK message, transmit a second transmission of user data to the second UE via the second transmit beam.

[0037] Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may further include operations, features, components, or instructions for switching from a first transmit beam to a second transmit beam based on a failure to receive or decode an ACK message.

[0038] Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may further include operations, features, components, or instructions for receiving an indication of a set of periodic intervals during which a second UE may be scheduled to send an initial transmission of user data, wherein the set of periodic intervals includes a first interval.

[0039] In some examples of the methods, apparatus, and non-transitory computer-readable media described herein, sending a second transmission of user data during a subsequent interval may include operations, features, components, or instructions for sending control information in a control channel indicating a location of the user data in a data channel.

[0040] In some examples of the methods, apparatus, and non-transitory computer-readable media described herein, a spatial diversity between the first transmit beam and the second transmit beam exceeds a threshold.

[0041] In some examples of the methods, apparatus, and non-transitory computer-readable media described herein, the indication indicates a second transmit beam.

[0042] In some examples of the methods, apparatus, and non-transitory computer-readable media described herein, identifying the second transmit beam includes determining a mapping between the first transmit beam and the second transmit beam based on a table.

[0043] A method for wireless communication at a first UE is described. The method may include receiving a set of transmit beams, reporting channel state information (CSI) for the set of transmit beams, receiving an indication of a first transmit beam in the set of transmit beams based on the reported CSI, wherein the first transmit beam is configured to transmit an initial transmission to the UE, identifying a second transmit beam in the set of transmit beams based on the indication, wherein the second transmit beam is configured to transmit a retransmission to the UE, transmitting a first transmission of user data to a second UE via the first transmit beam during a first interval, receiving a negative acknowledgement (NACK) message based on the first transmission, and transmitting a second transmission of user data on the second transmit beam during a subsequent interval based on receiving the NACK message.

[0044] An apparatus for wireless communication at a first UE is described. The apparatus may include a processor, a memory coupled to the processor, and instructions stored in the memory. The instructions may be executed by the processor to cause the apparatus to receive a set of transmit beams, report CSI of the set of transmit beams, receive an indication of a first transmit beam in the set of transmit beams based on the reported CSI, wherein the first transmit beam is configured to transmit an initial transmission to the UE, identify a second transmit beam in the set of transmit beams based on the indication, wherein the second transmit beam is configured to transmit a retransmission to the UE, transmit a first transmission of user data to a second UE via the first transmit beam during a first interval, receive a negative acknowledgement (NACK) message based on the first transmission, and transmit a second transmission of user data via the second transmit beam during a subsequent interval based on receiving the NACK message.

[0045] Another apparatus for wireless communication at a first UE is described. The apparatus may include means for receiving a set of transmit beams, reporting CSI for the set of transmit beams, means for receiving an indication of a first transmit beam in the set of transmit beams based on the reported CSI, wherein the first transmit beam is configured to transmit an initial transmission to the UE, means for identifying a second transmit beam in the set of transmit beams based on the indication, wherein the second transmit beam is configured to transmit a retransmission to the UE, means for transmitting a first transmission of user data to a second UE via the first transmit beam during a first interval, means for receiving a negative acknowledgement (NACK) message based on the first transmission, and means for transmitting a second transmission of user data via the second transmit beam during a subsequent interval based on receiving the NACK message.

[0046] A non-transitory computer-readable medium storing code for wireless communication at a first UE is described. The code may include instructions executable by a processor to receive a set of transmit beams, report CSI for the set of transmit beams, receive an indication of a first transmit beam in the set of transmit beams based on the reported CSI, wherein the first transmit beam is configured to transmit an initial transmission to the UE, identify a second transmit beam in the set of transmit beams based on the indication, wherein the second transmit beam is configured to transmit a retransmission to the UE, transmit a first transmission of user data to a second UE via the first transmit beam during a first interval, receive a negative acknowledgement (NACK) message based on the first transmission, and transmit a second transmission of user data via the second transmit beam during a subsequent interval based on receiving the NACK message.

[0047] In some examples of the methods, apparatus, and non-transitory computer-readable media described herein, the indication indicates a second transmit beam.

[0048] In some examples of the methods, apparatus, and non-transitory computer-readable media described herein, identifying the second transmit beam includes determining a mapping between the first transmit beam and the second transmit beam based on a table. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Figure 1 An example of a wireless communication system supporting switching to a backup beam in accordance with various aspects of the present disclosure is shown.

[0050] Figure 2A and 2B Aspects of a wireless communication subsystem supporting switching to a backup beam in accordance with various aspects of the various disclosures are shown.

[0051] Figure 3 Aspects of a wireless communication subsystem supporting switching to a backup beam in accordance with various aspects of the various disclosures are shown.

[0052] Figure 4 Aspects of exemplary communication resources supporting switching to a backup beam in accordance with various aspects of the various disclosures are shown.

[0053] Figure 5 Aspects of a process for switching to a backup beam in accordance with various aspects of the various disclosures are shown.

[0054] Figure 6 Aspects of a process for switching to a backup beam in accordance with various aspects of the various disclosures are shown.

[0055] Figure 7 and Figure 8 A block diagram of an apparatus supporting switching to a backup beam according to various aspects of the present disclosure is shown.

[0056] Fig. 9 A diagram of a system including a device supporting switching to a backup beam according to various aspects of the present disclosure is shown.

[0057] Fig.10 and Fig.11 A block diagram of an apparatus supporting switching to a backup beam according to various aspects of the present disclosure is shown.

[0058] Fig.12 A diagram of a system including a device supporting switching to a backup beam according to various aspects of the present disclosure is shown.

[0059] Figures 13 to 16 A flow chart illustrating a method of supporting switching to a backup beam according to various aspects of the present disclosure is shown. DETAILED DESCRIPTION

[0060] Operationally critical wireless communication systems may use ultra-reliable low-latency communication (URLLC) technology to wirelessly communicate data between devices. Operationally critical communications may include communications between automated components in a factory environment (e.g., a manufacturing facility). For example, URLLC may be required between a custom controller configured to issue commands based on sensor input (e.g., a programmable logic controller (PLC)) and a sensing and / or actuation (S / A) component. In some cases, operationally critical communication systems use beamforming transmissions and millimeter wave technology to transfer information between devices.

[0061] To meet reliability and low latency requirements, initial data transmissions between the PLC and S / A components may be sent during periodically scheduled resources, and retransmissions of data that were not successfully communicated between devices may be performed in an immediately subsequent control channel scheduled transmission. In some cases, the initial transmission of data fails due to blocking the path of the transmit beam used to send data between devices. In an automated factory environment, manufacturing components (e.g., robotic arms) may frequently enter the transmission path between wireless devices for short or extended periods of time. Therefore, if the blockage remains in the transmission path, retransmissions of failed data using the same transmit beam may similarly fail. Initial transmission and retransmission failures caused by constant blocking may cause the communication system's packet error rate to exceed a minimum error rate criterion and / or the time to transmit data between devices to exceed a delay criterion.

[0062] To increase the reliability of transmissions and reduce latency of transmissions in the presence of constant blocking, wireless communication systems may utilize backup transmit beams to transmit retransmissions of data that failed to be communicated between wireless devices on the primary transmit beam.

[0063] For example, the main transmit beam may be used for initial data transmission between wireless devices, and the backup transmit beam may be used for retransmission of data that failed to be transmitted in the initial data transmission. In some cases, in order to support transmission through the main transmit beam and the backup transmit beam, a preconfiguration process may be used to enable the wireless device to switch between the main transmit beam and the backup transmit beam in a coordinated manner. That is, the main transmit beam and the backup transmit beam may be identified before performing communication between wireless devices—for example, in addition to calculating the spatial diversity between multiple transmit beams, the transmitting device may identify the main transmit beam and the backup transmit beam based on the channel state information (CSI) reported from the receiving device for multiple transmit beams transmitted from the transmitting device. After the main transmit beam and the backup transmit beam are identified, the identification of the main transmit beam and the backup transmit beam may be shared between wireless devices. Therefore, during subsequent communications, the wireless device may perform initial data transmission through the main transmit beam, and may switch to the backup transmit beam to retransmit the data after the initial transmission of the data fails—for example, if the receiving device fails to receive or decode the data within a predetermined interval.

[0064] In some examples, similar techniques are used for direct transmissions between user devices (or "sidelink communications"). In some cases, a user device (e.g., a PLC) can similarly perform and manage a preconfiguration process with another user device (e.g., an S / A component). In other cases, in order to support sidelink transmissions on a main transmit beam and a backup transmit beam, a preconfiguration process involving a central scheduling node (e.g., a base station) is used to enable the user device to switch between the main transmit beam and the backup transmit beam in a coordinated manner. For example, the central scheduling node can identify the main and backup transmit beams for sidelink transmissions between user devices based on one or both of the CSI reported in the user devices. After identifying the main and backup transmit beams for sidelink transmission, the central scheduling node may indicate the identities of the main and backup transmit beams to the user device. Therefore, during communication, the user device can perform initial data sidelink transmission through the main transmit beam, and can switch to the backup transmit beam for sidelink retransmission of the data after the initial transmission of the data fails.

[0065] Various aspects of the present disclosure are initially described in the context of wireless communication systems and wireless communication subsystems. Specific examples of communication resource structures that support switching to a backup beam are then described, as well as a process flow that shows a series of operations that occur when switching to a backup beam. Aspects of the present disclosure are further illustrated and described with reference to apparatus diagrams, system diagrams, and flow charts related to switching to a backup beam.

[0066] Figure 1 An example of a wireless communication system supporting switching to a backup beam in accordance with various aspects of the present disclosure is shown.

[0067] The wireless communication system 100 may include a base station 105, a UE 115, and a core network 130. In some examples, the wireless communication system 100 may be a long term evolution (LTE) network, an LTE advanced (LTE-A) network, an LTE-A Pro network, or a new radio (NR) network. In some cases, the wireless communication system 100 may support enhanced broadband communications, ultra-reliable (e.g., mission-critical) communications, low-latency communications, communications with low-cost and low-complexity devices, or any combination thereof.

[0068] The base stations 105 may be dispersed throughout a geographic area to form the wireless communication system 100, and may be devices of different forms or with different capabilities. The base stations 105 and the UEs 115 may communicate wirelessly via one or more communication links 125. Each base station 105 may provide a geographic coverage area 110 over which the UEs 115 and the base stations 105 may establish communication links 125. The geographic coverage area 110 may be an example of a geographic area over which the base stations 105 and the UEs 115 support signal communication according to one or more radio access technologies.

[0069] The UEs 115 may be dispersed throughout the geographic coverage area 110 of the wireless communication system 100, and each UE 115 may be stationary or mobile, or both, at different times. The UEs 115 may be devices of different forms or with different capabilities. Figure 1 Some example UEs 115 are shown in FIG. Figure 1 As shown, the UE 115 described herein is capable of communicating with various types of devices, such as other UEs 115, base stations 105, or network devices (e.g., core network nodes, relay devices, integrated access and backhaul (IAB) nodes, or other network devices).

[0070] The base stations 105 may communicate with the core network 130 or with each other, or both. For example, the base stations 105 may interface with the core network 130 via a backhaul link 120 (e.g., via S1, N2, N3, or other interface). The base stations 105 may communicate with each other directly (e.g., directly between the base stations 105) or indirectly (e.g., via the core network 130), or both, via the backhaul link 120 (e.g., via X2, Xn, or other interface). In some examples, the backhaul link 120 may be or include one or more wireless links.

[0071] The one or more base stations 105 described herein may include or may be referred to by a person of ordinary skill in the art as a base station transceiver, a radio base station, an access point, a radio transceiver, a NodeB, an eNodeB (eNB), a next generation NodeB or a giga-NodeB (any of which may be referred to as a gNB), a Home NodeB, a Home eNodeB, or other suitable terminology.

[0072] UE 115 may include or may be referred to as a mobile device, a wireless device, a remote device, a handheld device, or a subscriber device, or some other suitable terminology, where in other examples, a "device" may also be referred to as a unit, a station, a terminal, or a client. UE 115 may also include or may be referred to as a personal electronic device such as a cellular phone, a personal digital assistant (PDA), a tablet computer, a laptop computer, or a personal computer. In some examples, UE 115 may include or be referred to as a wireless local loop (WLL) station, an Internet of Things (IoT) device, an Internet of Everything (IoE) device, a machine type communication (MTC) device, etc., which may be implemented in various objects such as home appliances, vehicles, meters, etc.

[0073] like Figure 1 As shown, the UE 115 described herein can communicate with various types of devices, such as other UEs 115 that can sometimes act as relays, as well as base stations 105 and network devices including macro eNBs or gNBs, small cell eNBs or gNBs, relay base stations, etc.

[0074] The UE 115 and the base station 105 may communicate wirelessly with each other via one or more communication links 125 through one or more carriers. The term "carrier" may refer to a set of radio frequency spectrum resources having a defined physical layer structure for supporting the communication link 125. For example, a carrier for the communication link 125 may include a portion of a radio frequency spectrum band (e.g., a bandwidth portion (BWP)) that operates according to a physical layer channel for a given radio access technology (e.g., LTE, LTE-A, LTE-A Pro, NR). Each physical layer channel may carry acquisition signaling (e.g., synchronization signals, system information), control signaling for coordinating carrier operations, user data, or other signaling. The wireless communication system 100 may support communication with the UE 115 using carrier aggregation or multi-carrier operation. The UE 115 may be configured with multiple downlink component carriers and one or more uplink component carriers according to the carrier aggregation configuration. Carrier aggregation may be used with both frequency division duplex (FDD) and time division duplex (TDD) component carriers.

[0075] The signal waveform transmitted via the carrier may be composed of multiple subcarriers (e.g., using multi-carrier modulation (MCM) techniques, such as orthogonal frequency division multiplexing (OFDM) or discrete Fourier transform spread OFDM (DFT-S-OFDM)). In a system employing MCM techniques, a resource element may include a symbol period (e.g., the duration of a modulation symbol) and a subcarrier, where the symbol period and the subcarrier spacing are inversely related. The number of bits carried by each resource element may depend on the modulation scheme (e.g., the order of the modulation scheme, the codec rate of the modulation scheme, or both). Therefore, the more resource elements received by the UE 115 and the higher the order of the modulation scheme, the higher the data rate may be for the UE 115. Wireless communication resources may refer to a combination of radio spectrum resources, time resources, and spatial resources (e.g., spatial layers or beams), and the use of multiple spatial layers may further increase the data rate or data integrity used to communicate with the UE 115.

[0076] The time interval of the base station 105 or the UE 115 can be expressed as a multiple of a basic time unit. For example, the basic time unit can refer to T s =1 / (Δf max ·N f ) seconds sampling period, where Δf max It can represent the maximum supported subcarrier spacing, and N f The maximum supported discrete Fourier transform (DFT) size may be indicated. The time intervals of the communication resources may be organized according to radio frames each having a specified duration (e.g., 10 milliseconds (ms)). Each radio frame may be identified by a system frame number (SFN) (e.g., ranging from 0 to 1023).

[0077] Each frame may include multiple consecutively numbered subframes or time slots, and each subframe or time slot may have the same duration. In some cases, the frame may be divided (e.g., in the time domain) into subframes, and each subframe may be further divided into multiple time slots. Alternatively, each frame may include a variable number of time slots, and the number of time slots may depend on the subcarrier spacing. Each time slot may include multiple symbol periods (e.g., depending on the length of the cyclic prefix preceding each symbol period). In some wireless communication systems, the time slot may be further divided into multiple mini-slots containing one or more symbols. In addition to the cyclic prefix, each symbol period may contain one or more (e.g., N ) symbol periods. f ) sampling period. The duration of a symbol period may depend on the subcarrier spacing or frequency band of operation.

[0078] A subframe, a time slot, a mini-slot, or a symbol may be the smallest scheduling unit (e.g., in the time domain) of the wireless communication system 100 and may be referred to as a transmission time interval (TTI). In some cases, the TTI duration (e.g., the number of symbol periods in a TTI) may be variable. Additionally or alternatively, the smallest scheduling unit of the wireless communication system 100 may be dynamically selected (e.g., in a burst of a shortened TTI (sTTI)).

[0079] Physical channels can be multiplexed on a carrier according to various techniques. Physical control channels and physical data channels can be multiplexed on a downlink carrier, for example, using a time division multiplexing (TDM) technique, a frequency division multiplexing (FDM) technique, or a hybrid TDM-FDM technique. The control region (e.g., a control resource set (core set)) of a physical control channel can be defined by multiple symbol periods and can be extended across the system bandwidth of a carrier or a subset of the system bandwidth. One or more control regions (e.g., core sets) can be configured for a set of UEs 115. For example, a UE 115 can monitor or search a control region to obtain control information according to one or more search space sets, and each search space set can include one or more control channel candidates in one or more aggregation levels arranged in a cascaded manner. The aggregation level of a control channel candidate may refer to multiple control channel resources (e.g., control channel elements (CCEs)) associated with coded information of a control information format having a given payload size. The search space set may include a common search space set configured for sending control information to multiple UEs 115 and a UE-specific search space set for sending control information to a specific UE 115.

[0080] In some examples, base stations 105 may be mobile, and thus provide communication coverage for mobile geographic coverage areas 110. In some examples, different geographic coverage areas 110 associated with different technologies may overlap, but the different geographic coverage areas 110 may be supported by the same base station 105. In other examples, overlapping geographic coverage areas 110 associated with different technologies may be supported by different base stations 105. The wireless communication system 100 may include, for example, a heterogeneous network in which different types of base stations 105 provide coverage for various geographic coverage areas 110 using the same or different radio access technologies.

[0081] The wireless communication system 100 may support synchronous or asynchronous operation. For synchronous operation, the base stations 105 may have similar frame timing, and transmissions from different base stations 105 may be approximately aligned in time. For asynchronous operation, the base stations 105 may have different frame timing, and in some examples, transmissions from different base stations 105 may not be aligned in time. The techniques described herein may be used for synchronous or asynchronous operation.

[0082] Some UEs 115, such as MTC or IoT devices, may be low-cost or low-complexity devices and may provide automated communication between machines (e.g., via machine-to-machine (M2M) communication). M2M communication or MTC may refer to data communication technology that allows devices to communicate with each other or with a base station 105 without human intervention. In some examples, M2M communication or MTC may include communications from devices that integrate sensors or meters to measure or capture information and relay such information to a central server or application that utilizes the information or presents the information to a person interacting with the application. Some UEs 115 may be designed to collect information or implement automated behavior of machines or other devices. Examples of applications for MTC devices include smart metering, inventory monitoring, water level monitoring, equipment monitoring, healthcare monitoring, wildlife monitoring, weather and geological event monitoring, fleet management and tracking, remote security sensing, physical access control, and transaction-based business charging.

[0083] The wireless communication system 100 may be configured to support ultra-reliable communication or low-latency communication, or various combinations thereof. For example, the wireless communication system 100 may be configured to support ultra-reliable, low-latency or mission-critical communications. UE 115 may be designed to support ultra-reliable, low-latency or critical functions (e.g., mission-critical functions). Ultra-reliable communications may include private communications or group communications, and may be supported by one or more mission-critical services such as mission-critical push-to-talk (MCPTT), mission-critical video (MCVideo), or mission-critical data (MCData). Support for mission-critical functions may include service prioritization, and mission-critical services may be used for public safety or commercial applications. The terms ultra-reliable, low-latency, mission-critical, and ultra-reliable low-latency may be used interchangeably herein.

[0084] In some cases, UE 115 is also able to communicate directly with other UE 115 via a device-to-device (D2D) communication link 135 (e.g., using a peer-to-peer (P2P) or D2D protocol), which may also be referred to as a side link. One or more UEs 115 utilizing D2D communication may be within the geographic coverage area 110 of the base station 105. Other UEs 115 in such a group may be outside the geographic coverage area 110 of the base station 105, or may not receive transmissions from the base station 105 for other reasons. In some cases, a group of UEs 115 communicating via D2D communication may utilize a one-to-many (1:M) system in which each UE 115 transmits to each other UE 115 in the group. In some examples, the base station 105 facilitates the scheduling of resources for D2D communication. In other cases, D2D communication is performed between UEs 115 without involving the base station 105.

[0085] In some systems, the D2D communication link 135 can be an example of a communication channel between vehicles (e.g., UE 115), such as a sidelink communication channel. In some examples, vehicles can communicate using vehicle-to-everything (V2X) communications, vehicle-to-vehicle (V2V) communications, or some combination of these communications. Vehicles can signal information related to traffic conditions, signal scheduling, weather, safety, emergency situations, or any other information related to the V2X system. In some cases, vehicles in a V2X system can communicate with roadside infrastructure (e.g., roadside units) or with a network, or both, using vehicle-to-network (V2N) communications via one or more network nodes (e.g., base station 105).

[0086] The core network 130 may provide user authentication, access authorization, tracking, Internet Protocol (IP) connection, and other access, routing, or mobility functions. The core network 130 may be an evolved packet core (EPC) or a 5G core (5GC), which may include at least one control plane entity (e.g., a mobility management entity (MME), an access and mobility management function (AMF)) for managing access and mobility and at least one user plane entity (e.g., a serving gateway (S-GW), a packet data network (PDN) gateway (P-GW), a user plane function (UPF)) for routing packets or interconnections to an external network. The control plane entity may manage non-access stratum (NAS) functions of UE 115 served by a base station 105 associated with the core network 130, such as mobility, authentication, and bearer management. User IP packets may be transmitted through user plane entities, which may provide IP address allocation and other functions. The user plane entity may be connected to a network operator IP service 150. The operator IP service 150 may include access to the Internet, an intranet (multiple), an IP multimedia subsystem (IMS), or a packet-switched streaming media service.

[0087] Some network devices, such as base stations 105, may include subcomponents, such as access network entities 140, which may be examples of access node controllers (ANCs). Each access network entity 140 may communicate with UE 115 through multiple other access network transport entities 145, which may be referred to as radio heads, smart radio heads, or transmit / receive points (TRPs). Each access network transport entity 145 may include one or more antenna panels. In some configurations, the various functions of each access network entity 140 or base station 105 may be distributed across various network devices (e.g., radio heads and ANCs) or merged into a single network device (e.g., base station 105).

[0088] The wireless communication system 100 may operate using one or more frequency bands, such as in the range of 300 megahertz (MHz) to 300 gigahertz (GHz). Typically, the region of 300 MHz to 3 GHz is referred to as the ultra-high frequency (UHF) region or decimeter band because the wavelength range is approximately 1 decimeter to 1 meter long. UHF waves may be blocked or redirected by buildings and environmental features, but these waves may penetrate structures sufficiently for macro cells to provide service to UEs 115 located indoors. Transmissions using UHF waves may be associated with smaller antennas and shorter ranges (e.g., less than 100 kilometers) than transmissions using smaller frequencies and longer waves in the high frequency (HF) or very high frequency (VHF) portions of the spectrum with frequencies less than 300 MHz.

[0089] The wireless communication system 100 may also operate in the super high frequency (SHF) region (also known as the centimeter band) using a frequency band from 3 GHz to 30 GHz or in the extremely high frequency (EHF) region of the spectrum (e.g., from 30 GHz to 300 GHz, also known as the millimeter band). In some examples, the wireless communication system 100 may support millimeter wave (mmW) communications between the UE 115 and the base station 105, and the EHF antennas of each device may be smaller and more closely spaced than the UHF antennas. In some cases, this may facilitate the use of antenna arrays within the device. However, the propagation of EHF transmissions may be subject to greater atmospheric attenuation and a shorter range than SHF or UHF transmissions. The techniques disclosed herein may be employed across transmissions using one or more different frequency regions, and the designated use of frequency bands across these frequency regions may vary by country or regulatory agency.

[0090] The wireless communication system 100 can utilize licensed and unlicensed radio frequency spectrum bands. For example, the wireless communication system 100 can adopt license assisted access (LAA), LTE unlicensed (LTE-U) radio access technology, or NR technology in unlicensed bands such as the 5 GHz industrial, scientific, and medical (ISM) band. When operating in an unlicensed radio spectrum band, devices such as base stations 105 and UEs 115 can use carrier sensing for conflict detection and avoidance. In some cases, operations in unlicensed bands can be based on carrier aggregation configurations and component carriers operating in licensed bands (e.g., LAA). Operations in unlicensed spectrum can include downlink transmissions, uplink transmissions, P2P transmissions, D2D transmissions, and the like.

[0091] The base station 105 or UE 115 may be equipped with multiple antennas, which can be used to employ technologies such as transmit diversity, receive diversity, multiple-input multiple-output (MIMO) communications, or beamforming. The antennas of the base station 105 or UE 115 may be located in one or more antenna arrays or antenna panels, which may support MIMO operations, or transmit or receive beamforming. For example, one or more base station antennas or antenna arrays may be co-located on an antenna assembly (e.g., an antenna tower). In some cases, the antennas or antenna arrays associated with the base station 105 may be located in different geographical locations. The base station 105 may have an antenna array with several rows and columns of antenna ports, which the base station 105 may use to support beamforming for communications with the UE 115. Similarly, the UE 115 may have one or more antenna arrays, which may support various MIMO or beamforming operations. Additionally or alternatively, the antenna panel may support radio frequency beamforming for signals sent via the antenna ports.

[0092] The base station 105 or UE 115 can use MIMO communication to exploit multipath signal propagation and improve spectral efficiency by sending or receiving multiple signals via different spatial layers. This technology may be referred to as spatial multiplexing. For example, multiple signals may be sent by a transmitting device via different antennas or different combinations of antennas. Similarly, multiple signals may be received by a receiving device via different antennas or different antenna combinations. Each of the multiple signals may be referred to as a separate spatial stream and may carry bits associated with the same data stream (e.g., the same codeword) or different data streams (e.g., different codewords). Different spatial layers may be associated with different antenna ports for channel measurement and reporting. MIMO technology includes single-user MIMO (SU-MIMO) (where multiple spatial layers are sent to the same receiving device), and multi-user MIMO (MU-MIMO) (where multiple spatial layers are sent to multiple devices).

[0093] Beamforming, which may also be referred to as spatial filtering, directional transmission, or directional reception, is a signal processing technique that may be used at a transmitting device or a receiving device (e.g., a base station 105 or a UE 115) to shape or direct an antenna beam (e.g., a transmit beam, a receive beam) along a spatial path between the transmitting device and the receiving device. Beamforming may be achieved by combining signals transmitted via antenna elements of an antenna array so that some signals propagating in a first direction relative to the antenna array experience constructive interference and other signals experience destructive interference. Adjustment of signals transmitted via antenna elements may include the transmitting device or the receiving device applying an amplitude offset, a phase offset, or both to signals carried via antenna elements associated with the device. Adjustments associated with each antenna element may be defined by a set of beamforming weights associated with an orientation (e.g., relative to the antenna array of the transmitting device or the receiving device, or relative to some other direction).

[0094] The base station 105 or the UE 115 may use beam scanning techniques as part of a beamforming operation. For example, the base station 105 may use multiple antennas or antenna arrays (e.g., antenna panels) to perform beamforming operations for directional communications with the UE 115. Some signals (e.g., synchronization signals, reference signals, beam selection signals, or other control signals) may be sent multiple times by the base station 105 in different directions. For example, the base station 105 may send signals according to different sets of beamforming weights associated with different transmission directions. Transmissions in different beam directions may be used (e.g., by a transmitting device such as the base station 105 or a receiving device such as the UE 115) to identify a beam direction for subsequent transmission and / or reception by the base station 105.

[0095] Some signals, such as data signals associated with a receiving device, may be transmitted by base station 105 in a single beam direction (e.g., a direction associated with a receiving device such as UE 115). In some examples, a beam direction associated with transmission along a single beam direction may be determined based on signals transmitted in different beam directions. For example, UE 115 may receive one or more of the signals transmitted by base station 105 in different directions and may report to base station 105 an indication of the signal received by UE 115 with the highest signal quality or other acceptable signal quality.

[0096] In some cases, transmissions by a device (e.g., by a base station 105 or a UE 115) may be performed using multiple beam directions, and the device may use a combination of digital precoding or radio frequency beamforming to generate a combined beam for transmission (e.g., from a base station 105 to a UE 115). The UE 115 may report feedback indicating precoding weights for one or more beam directions, and the feedback may correspond to the number of configured beams across the system bandwidth or one or more subbands. The base station 105 may send reference signals (e.g., cell-specific reference signals (CRS), channel state information reference signals (CSI-RS)) that may be precoded or not precoded. The UE 115 may provide feedback for beam selection, which may be a precoding matrix indicator (PMI) or codebook-based feedback (e.g., a multi-panel type codebook, a linear combination type codebook, a port selection type codebook). Although these techniques are described with reference to signals sent by base station 105 in one or more directions, UE 115 may employ similar techniques for sending signals multiple times in different directions (e.g., for identifying a beam direction for subsequent transmission or reception by UE 115) or for sending signals in a single direction (e.g., for sending data to a receiving device).

[0097] A receiving device (e.g., UE 115) may try multiple reception configurations (e.g., directional listening) when receiving various signals (e.g., synchronization signals, reference signals, beam selection signals, or other control signals) from a base station 105. For example, the receiving device may try multiple reception directions by receiving via different antenna subarrays, by processing received signals according to different antenna subarrays, by receiving according to different reception beamforming weight sets (e.g., different directional listening weight sets) applied to signals received at multiple antenna elements of an antenna array, or by processing received signals according to different reception beamforming weight sets applied to signals received at multiple antenna elements of an antenna array, any of which may be referred to as "listening" according to different reception configurations or reception directions. In some examples, a receiving device may receive along a single beam direction using a single reception configuration (e.g., when receiving a data signal). The single reception configuration may be aligned in a beam direction determined based on listening according to different reception configuration directions (e.g., a beam direction with the highest signal strength, the highest signal-to-noise ratio (SNR), or otherwise acceptable signal quality determined based on listening according to multiple beam directions).

[0098] The wireless communication system 100 can be a packet-based network operating according to a layered protocol stack. In the user plane, the communication at the bearer or packet data aggregation protocol (PDCP) layer can be IP-based. The radio link control (RLC) layer can perform packet segmentation and reorganization to communicate on a logical channel. The medium access control (MAC) layer can perform priority processing and multiplex logical channels into transport channels. The MAC layer can also use error detection technology, error correction technology, or both to support retransmission of the MAC layer to improve link efficiency. In the control plane, the radio resource control (RRC) protocol layer can provide the establishment, configuration and maintenance of the RRC connection between the base station 105 or the core network 130 that supports the radio bearer for user plane data. At the physical layer, the transport channel can be mapped to the physical channel.

[0099] UE 115 and base station 105 can support retransmission of data to increase the possibility of successfully receiving data. Hybrid automatic repeat request (HARQ) feedback is a technique for increasing the possibility of correctly receiving data through communication link 125. HARQ can include a combination of error detection (e.g., using cyclic redundancy check (CRC)), forward error correction (FEC) and retransmission (e.g., automatic repeat request (ARQ)). HARQ can improve the throughput of the MAC layer under poor radio conditions (e.g., low signal-to-noise ratio conditions). In some cases, the device can support same-slot HARQ feedback, where the device can provide HARQ feedback in a specific time slot for data received in a previous symbol in the time slot. In other cases, the device can provide HARQ feedback in a subsequent time slot or according to some other time interval.

[0100] Operationally critical communications systems may use URLLC technology to wirelessly communicate data between devices. Operationally critical communications may include communications between automated components in a factory environment (e.g., a manufacturing facility). For example, URLLC may be required between a custom controller and an S / A component that is configured to issue commands based on sensor input (or PLC). In some cases, operationally critical communications systems use beamforming transmissions and millimeter wave technology to pass information between devices.

[0101] To meet reliability and low latency requirements, initial data transmissions between the PLC and S / A components may be sent during periodically scheduled resources, and retransmissions of unsuccessfully received data may be performed in an immediately subsequent control channel scheduled transmission. In some cases, the initial transmission of data fails due to blockage of the path into the transmit beam used to send data between devices. In an automated factory environment, manufacturing components (e.g., robotic arms) may frequently enter the transmission path between wireless devices for brief or extended periods of time. Therefore, if blockage remains in the transmission path, retransmissions of failed data using the same transmit beam as the initial transmission of the data may similarly fail. Initial transmission and retransmission failures caused by constant blockage may cause the communication system's packet error rate to exceed a minimum error rate criterion and / or the time to transmit data between devices to exceed a delay criterion.

[0102] To increase transmission reliability and latency in the presence of constant congestion, the communication system may utilize backup transmit beams to carry retransmitted data between devices.

[0103] Figure 2A Aspects of a wireless communication subsystem supporting switching to a backup beam according to various aspects of various disclosures are shown. The wireless communication subsystem 200-a may include a base station 205-a, which may be as described in reference Figure 1 An example of a base station as described; and UE 215-a, which may be as described in reference Figure 1 Base station 205-a and UE 215-a may use the techniques described herein and refer to Figure 1 Communicate with each other within coverage area 210-a.

[0104] As discussed herein, retransmissions of data transmissions that failed due to congestion may similarly fail when the retransmissions are sent over the same communication path as the initial transmission. To increase the reliability of the retransmissions and mitigate the effects of congestion, the memory system may send the retransmissions on a different, spatially diverse transmit beam than the transmit beam used to send the corresponding initial data transmission.

[0105] For example, the base station 205-a can be configured to perform beamforming transmissions in multiple spatial directions. In some cases, the path of the beamforming transmission is called a transmit beam. In some examples, the base station performs a beam scanning process. During the beam scanning process, the base station 205-a can send multiple beamforming transmissions in multiple directions—the paths of the beamforming transmissions can include, but are not limited to, the main transmit beam 220-a and the backup transmit beam 230-a. In some cases, the beamformed transmissions can be reflected from other objects within the coverage area 210-a, directing the beamformed transmissions originally sent in a direction away from the UE toward the UE (e.g., UE 215-a). For example, the backup transmit beam 230-a can be sent in a first direction away from the UE 215-a, but can be reflected from the reflector 235-a so that the backup transmit beam 230-a reaches the UE 215-a.

[0106] The UE 215-a may receive all or part of the beamforming transmission sent from the base station 205-a. The UE 215-a may report the CSI for each beamforming transmission received at the UE 215-a to the base station 205-a. The CSI may include channel quality information, a rank indication, and / or a precoding matrix indicator.

[0107] The base station 205-a can use the reported CSI to identify a subset of beamforming transmissions that meet spatial diversity and / or channel quality thresholds. For example, the base station 205-a can identify that a signal sent through the main transmit beam 220-a and a signal sent through the backup transmit beam 230-a are received at the UE 215-a with a signal-to-noise ratio exceeding a first threshold. The base station 205-a can also identify that the spatial diversity between the main transmit beam 220-a and the backup transmit beam 230-a exceeds a second threshold. In some examples, the base station 205-a can identify the main transmit beam 220-a as a candidate for initial data transmission and identify the backup transmit beam 230-a for retransmission after determining that the main transmit beam 220-a exhibits a higher channel quality than the backup transmit beam 230-a. By identifying a spatial diversity transmit beam backup to when a main transmit beam is blocked, the wireless communication subsystem 200-a can adaptively perform communications around a blockage in a path moved to the main transmit beam after configuring the main transmit beam between the base station 205-a and the UE 215-a.

[0108] After identifying the main transmit beam 220-a and the backup transmit beam 230-a, the base station 205-a may send an indication to the UE 215-a indicating that a subsequent initial data transmission will be sent via the main transmit beam 220-a. The indication may also indicate that subsequent retransmissions will be sent via the backup transmit beam 230-a. After receiving the indication of the main transmit beam 220-a, the UE 215-a may tune the main receive beam to correspond to the main transmit beam 220-a, and may tune the backup receive beam to correspond to the backup transmit beam 230-a. That is, the UE 215-a may configure the antenna at the UE 215-a in a first configuration to receive transmissions in the direction of receiving the main transmit beam 220-a, and may configure the antenna at the UE 215-a in a second configuration to receive transmissions in the direction of receiving the backup transmit beam 230-a. In some cases, the antenna at UE 215-a may not be reconfigured to switch from a primary receive beam to a backup receive beam—that is, UE 215-a may use a single antenna configuration and may not be configured to receive information through different receive beams. By indicating the primary and backup transmit beams to the UE, the base station and the UE can perform coordinated switching between the primary and backup transmit beams without using additional signaling.

[0109] The base station 205-a may perform an initial data transmission to one or more UEs (including UE 215-a) via the main transmit beam 220-a. In some cases, the base station 205-a schedules periodic resources in the main transmit beam 220-a for the UE using the main transmit beam 220-a. Thus, the base station 205-a may send the initial data transmission without including control channel resources, and a UE such as UE 215-a may receive the initial data transmission without decoding the control channel. By not including control channel resources, the base station 205-a may include more data in the initial data transmission via the main transmit beam 220-a. In this document and Figure 4 Performing initial data transmission on periodically scheduled resources is discussed in more detail in.

[0110] In some cases, the blocker 225-a may enter the path of the primary transmit beam 220-a, thereby reducing the transmission of the base station 205-a through the primary transmit beam 220-a before the transmission reaches the UE 215-a. In some cases, the blocker 225-a causes the UE 215-a to be unable to receive (e.g., within a scheduled interval) or decode the initial data transmission. After failing to receive or decode the transmission, the UE 215-a may send a negative acknowledgement (NACK) message to the base station 205-a indicating that the UE 215-a failed to receive or decode the transmission. The UE 215-a may also reconfigure its antenna before or simultaneously with sending the NACK message so that the receive beam from the UE 215-a corresponds to the incoming direction of the backup transmit beam 230-a.

[0111] After receiving the NACK message or not receiving feedback from UE 215-a, base station 205-a can reconfigure the antennas at base station 205-a (e.g., by assigning different weights to components of transmissions performed on different antennas) to perform transmissions via backup transmit beam 230-a. Base station 205-a can then send data from the failed transmission in a retransmission via backup transmit beam 230-a. By performing the retransmission on backup transmit beam 230-a, the retransmission can reach the location of UE 215-a unimpeded. Therefore, UE 215-a can successfully receive and decode the data included in the retransmission.

[0112] In some cases, the retransmission includes control channel resources and data resources, wherein control information in the control channel resources indicates the location of data resources for UEs (including UE 215-a) that failed to receive the initial data transmission via the main transmit beam 220-a. By using the control channel resources, the base station 205-a can dynamically retransmit data only for UEs that failed to indicate successful reception of the initial data transmission. Figure 4 Performing retransmission of data using data resources scheduled by a control channel is discussed in more detail in.

[0113] After successfully receiving and decoding the data, UE 215-a may send an acknowledgment (ACK) message to base station 205-a, for example, using the same path as backup transmit beam 230-a, and may reconfigure the antenna at UE 215-a to form a receive beam from UE 215-a in the direction of primary transmit beam 220-a. Base station 205-a may similarly reconfigure the antenna at base station 205-a to form the primary transmit beam 220-a—in some cases, base station 205-a reconfigures the antenna after sending a retransmission to UE 215-a. Base station 205-a may then resume transmission to UEs (including UE 215-a) on primary transmit beam 220-a, for example, based on periodically scheduled resources.

[0114] In some cases, the blockage 225-a may leave the path of the main transmit beam 220-a, and the base station 205-a may perform a successful transmission to the UE 215-a via the main transmit beam 220-a. In other cases, the blockage 225-a may remain in the path of the main transmit beam 220-a, and the base station 205-a may continue to perform an unsuccessful transmission to the UE 215-a via the main transmit beam 220-a. If the blockage 225-a still exists, the base station 205-a and the UE 215-a may again fall back to the backup transmit beam 230-a. In some cases, the base station 205-a and the UE 215-a repeat the process until the blockage 225-a is removed from the path of the main transmit beam 220-a. In other cases, the base station 205-a and the UE 215-a identify a new primary transmit beam and a new backup transmit beam according to the above-described techniques after a threshold number of transmission failures occur on the primary transmit beam 220-a.

[0115] Figure 2B Aspects of a wireless communication subsystem supporting switching to a backup beam according to various aspects of various disclosures are shown. The wireless communication subsystem 200-b may include a first TRP 240-b and a second TRP 250-b, which may be as described in reference Figure 1 An example of an access network transmission entity; and UE 215-b, which may be as shown in reference Figure 1 The first TRP 240-b and the second TRP 250-b may use the techniques described herein and refer to Figure 1 and 2A Communicate with UE 215-b within the first coverage area 245-b and the second coverage area 255-b.

[0116] As discussed herein, to increase the reliability of retransmissions and mitigate the effects of blocking, a memory system can send retransmissions on transmit beams that originate from locations different than transmit beams used to send corresponding initial data transmissions.

[0117] For example, a base station is capable of transmitting data to a UE (e.g., UE 215-b) from different transmission points, which include a first TRP 240-b and a second TRP 250-b that are physically separated from each other. In some cases, the transmission from the first TRP 240-b to the UE 215-b may be referred to as a main transmit beam 220-b, and the transmission from the second TRP 250-b to the UE 215-b may be referred to as a backup transmit beam 230-b. During the beam scanning process, the UE 215-b may receive a transmission through a transmit beam, which includes the main transmit beam 220-b and the backup transmit beam 230-b. The UE 215-b may report the CSI of the transmission received on the transmit beam to the base station that is communicatively connected to the different transmission points.

[0118] The base station can use the reported CSI to identify that transmissions through the main transmit beam 220-b and the backup transmit beam 230-b exceed the channel quality. The base station can also determine that the main transmit beam 220-b and the backup transmit beam 230-b exceed the spatial diversity threshold based on determining that the main transmit beam 220-b and the backup transmit beam 230-b originate from different TRPs.

[0119] After identifying the primary transmit beam 220-b and the backup transmit beam 230-b, the base station may send an indication to the UE 215-b—for example, via one of the first TRP 240-b or the second TRP 250-b—indicating that a subsequent initial data transmission will be sent via the primary transmit beam 220-b. The indication may also indicate that a subsequent retransmission will be sent via the backup transmit beam 230-b.

[0120] The first TRP 240-b may perform an initial data transmission to a UE (including UE 215-b) via the main transmit beam 220-b. In some cases, the first TRP 240-b schedules periodic resources for UE 215-b to receive the initial data transmission without decoding the control channel. Figure 4 Performing initial data transmission on periodically scheduled resources is discussed in more detail in.

[0121] In some cases, the blocker 225-b may enter the path of the primary transmit beam 220-b, thereby degrading the transmission to the UE 215-b. In some cases, the blocker 225-b causes the UE 215-b to be unable to receive (e.g., within the scheduled interval) or decode the initial data transmission sent on the primary transmit beam 220-b. After failing to receive or decode the initial data transmission, the UE 215-b may send a NACK message to the first TRP 240-b and reconfigure the antenna at the UE 215-b so that the receive beam from the UE 215-b corresponds to the incoming direction of the backup transmit beam 230-b. In some cases, the UE 215-b may avoid reconfiguring the antenna at the UE 215-b after sending the NACK message—for example, the UE 215-b may use a single antenna configuration, or may not use a directional antenna configuration to receive the transmission.

[0122] After the first TRP 240-b receives a NACK message or no feedback from UE 215-b, the base station may route the retransmission of the initial data to the second TRP 250-b. Thus, the second TRP 250-b may perform the retransmission of the initial data that was not verified to be successfully received at the designated UE (including UE 215-b) through the backup transmit beam 230-b. In some cases, the retransmission may include a control channel resource that includes control information for scheduling data resources for the designated UE in the corresponding data channel resource. In this document and Figure 4 Retransmission of data using data resources scheduled by a control channel is discussed in more detail in . By performing retransmissions at different TRPs, the base station can achieve spatial diversity between transmissions and retransmissions, mitigating the impact of congestion into the primary transmission path.

[0123] In some cases, UE 215-b successfully receives and decodes the retransmission via the backup transmit beam 230-b (e.g., because there is no blockage between the second TRP 250-b and UE 215-b). After successfully decoding the retransmission, UE 215-b can send an ACK message to the second TRP 250-b, and the antenna at UE 215-b can be reconfigured to form a receive beam in the direction of the main transmit beam 220-b. In some cases, the first TRP 240-b and UE 215-b successfully communicate data after UE 215-b returns to the main transmit beam—e.g., if the blockage 225-b leaves the path of the main transmit beam 220-b. In other cases, transmissions between the first TRP 240-b and UE 215-b continue to fail—e.g., due to the continued presence of the blockage 225-b in the path of the main transmit beam 220-b. In some examples, in accordance with the techniques described above, the base station identifies new primary and / or secondary transmit beams based on a number of transmission failures exceeding a threshold on the primary transmit beam 220-b.

[0124] Figure 3 Aspects of a wireless communication subsystem supporting switching to a backup beam according to various aspects of the various disclosures are shown. The wireless communication subsystem 300 may include a base station 305, which may be as described in reference Figure 1 and Figure 3 An example of a base station as described above; and UE 315, which may be as described in reference Figure 1 , Figure 2A and Figure 2B Base station 305 and UE 315 can use the techniques described herein and refer to Figure 1 , Figure 2A and Figure 2B Communicate with each other within coverage area 310 .

[0125] The wireless communication subsystem 300 may also include a PLC 340, which may communicate with the base station 305 and may be configured to communicate directly with the UE 315. Direct communication between the PLC 340 and the UE 315 may be referred to as sidelink communication. In some cases, the PLC 340 may schedule the communication between the PLC 340 and the UE 315. In other cases, the base station 305 may schedule the communication between the PLC 340 and the UE 315.

[0126] As discussed herein, retransmissions of data transmissions that failed due to congestion may similarly fail when the retransmissions are sent over the same communication path as the initial transmission. To increase the reliability of the retransmissions and mitigate the effects of congestion, the memory system may send the retransmissions on a different, spatially diverse transmit beam than the transmit beam used to send the corresponding initial data transmission.

[0127] For example, PLC 340 can be configured to perform beamforming transmissions in multiple spatial directions. In some cases, PLC 340 performs a beam scanning process that includes performing beamforming transmissions on primary transmit beam 320 and backup transmit beam 330. In some examples, backup transmit beam 330 is reflected from reflector 335, and backup transmit beam 330 is directed toward UE 315.

[0128] UE 315 may report CSI for each beamforming transmission received at UE 315. In some cases, UE 315 reports CSI directly to PLC 340. When UE 315 reports CSI directly to PLC 340, PLC 340 may identify primary transmit beam 320 and backup transmit beam 330 and perform communication therethrough, as described with reference to FIG. Figure 2A discussed.

[0129] In other cases, the UE 315 reports the CSI to the base station 305 on the first communication link 345. The first communication link 345 can be configured for communication using beamforming. The base station 305 can process the received CSI to identify the main transmit beam 320 and the backup transmit beam 330. For example, the base station 305 can determine that both the main transmit beam 320 and the backup transmit beam 330 exceed a channel quality threshold. In addition, the base station 305 can determine that the spatial diversity between the main transmit beam 320 and the backup transmit beam 330 exceeds a spatial diversity threshold.

[0130] After identifying the primary transmit beam 320 and the backup transmit beam 330, the base station 305 may send an indication to both the PLC 340 and the UE 315 indicating that subsequent sidelink communications will use the primary transmit beam 320 for initial data transmission. The indication may also indicate that the backup transmit beam 330 is used for retransmission of failed initial data transmissions. In some cases, the base station 305 indicates the primary transmit beam 320 and the backup transmit beam 330 to the PLC 340 on the second communication link 350, which may be configured for communication using beamforming.

[0131] The PLC 340 may perform an initial data transmission to the UE 315 on the primary transmit beam 320. In some cases, the PLC 340 schedules periodic resources for the UE 315 in the primary transmit beam 320 for the initial data transmission. In other cases, the base station 305 schedules resources for the PLC 340 and the UE 315 to perform the initial data transmission on the primary transmit beam 320. Figure 4Performing initial data transmission on periodically scheduled resources is discussed in more detail in. In other cases, PLC 340 performs initial data transmission to UE 315 on the primary transmit beam using data transmission scheduled by the control channel.

[0132] In some cases, the blockage 325 may enter the path of the primary transmit beam 320, and the UE 315 may fail to receive or decode the initial data transmission from the PLC 340. Therefore, the UE 315 may, for example, send a NACK message to the PLC 340 on the primary transmit beam 320. The UE 315 may also reconfigure its antenna to form a receive beam in the direction of the backup transmit beam 330 based on the failure to receive or decode the initial data transmission. In some cases, the UE 315 may not reconfigure its antenna to form a receive beam—e.g., the UE 315 may not be configured to use directional receive transmissions.

[0133] PLC 340 may also reconfigure its antenna to form a backup transmit beam after receiving a NACK message or no feedback from UE 315. PLC 340 may then perform a retransmission of the data included in the failed initial transmission on backup transmit beam 330.

[0134] In some cases, the UE 315 receives and decodes the retransmission via the backup transmit beam 330—e.g., due to the absence of obstruction in the path of the backup transmit beam 330. After successfully decoding the retransmission, the UE 315 may send an ACK message to the PLC 340—e.g., using the same communication path as the backup transmit beam 330—and may reconfigure the antenna at the UE 315 to form a receive beam in the direction of the primary transmit beam 320. The PLC 340 may similarly reconfigure the antenna to form the primary transmit beam 320, and the PLC and UE 315 may resume initial data communications on the primary transmit beam 320.

[0135] In some cases, the blockage 325 may be moved out of the path of the primary transmit beam 320, and a subsequent initial data transmission may be successfully communicated between the PLC 340 and the UE 315 on the primary transmit beam 320. In other cases, the blockage 325 may remain in the path of the primary transmit beam 320, and the PLC 340 and the UE 315 may similarly fall back to the backup transmit beam 330. In some cases, the PLC 340 may be triggered by itself, or by the base station 305, to perform an additional beam sweeping process. If the PLC 340 performs the beam sweeping process by itself, the PLC 340 may indicate to the base station 305 that the beam sweeping process has been performed. After the PLC 340 performs the beam sweeping process, the UE 315 may report CSI to the base station 305, and the base station 305 may identify the new primary and backup transmit beams. The base station 305 may then indicate the new primary and backup transmit beams to the PLC 340 and the UE 315 , for example, over the first communication link 345 and the second communication link 350 .

[0136] Figure 4 Aspects of exemplary communication resources supporting switching to a backup beam according to various aspects of various disclosures are shown. Communication resources 400 may include downlink data resources (e.g., first UE resources 405 and second UE resources 410); a first uplink feedback resource set (e.g., first feedback resource 415 and second feedback resource 420); control channel resources 425; data channel resources (e.g., data channel resources 430); and a second uplink feedback resource set (e.g., third feedback resource 440). In some cases, the control information in the control channel resources 425 may be used to schedule data channel resources for a receiving device.

[0137] In some cases, the downlink data resources may be separated from the first set of uplink feedback resources by a first processing time 450. In some cases, the first processing time 450 includes the time when the receiving device performs actions and makes sensor measurements. The first set of uplink resources may be separated from the control channel resources 425 by a second processing time 455. The second processing time 455 may include the time when the transmitting device determines whether an initial data transmission on the downlink data resources is successfully received and processes the received measurements. The data channel resources may be separated from the second set of uplink feedback resources by a third processing time 460. The third processing time may include the time when the receiving device performs actions and makes sensor measurements.

[0138] In some cases, the initial transmission 465 includes downlink data resources and a first uplink feedback set. The initial transmission 465 may be sent in a first time slot 475. The first time slot 475 may extend by 0.5 ms. In some cases, the initial transmission 465 is sent on a first transmit beam.

[0139] The retransmission 470 may include control channel resources 425, data channel resources, and a second set of uplink feedback resources. The retransmission 470 may be sent in a second time slot 480, which may be further extended by 0.5 ms. In some cases, the retransmission 470 includes UE data that was originally sent in the initial transmission 465 but failed (e.g., due to congestion). In some cases, the retransmission 470 is sent on a second transmit beam. In some cases, the first time slot 475 and the second time slot 480 may constitute a subframe.

[0140] In some examples, the first UE is scheduled to receive an initial data transmission on the periodically scheduled data resources that include the first UE resources 405. Thus, the first UE may receive or expect to receive the initial data transmission on the first UE resources 405. The second UE may similarly receive or expect to receive the initial data transmission on the second UE resources 410. As discussed herein, blocking may prevent the second UE from receiving and / or decoding the initial data transmission sent on the second UE resources 410—e.g., due to blocking a path into a first transmit beam that includes the second UE resources 410.

[0141] After the downlink data resource ends, the first and second UEs may process and decode any received signals during the first processing time 450. In some examples, the first UE may successfully decode the data transmission and may perform actions based on the data. The first UE may also perform sensor measurements and prepare an ACK message for transmission to the transmitting device. In some examples, the second UE may not be able to receive or decode signals received during the second UE resource 410 and may perform sensor measurements and / or prepare a NACK message for transmission to the transmitting device.

[0142] After the first processing time 450 ends, the first UE may send its generated information on the first feedback resource 415, and the second UE may send its generated information on the second feedback resource 420. In some cases, the uplink feedback reaches the transmitting device. In other cases, the uplink feedback fails to reach the transmitting device - for example, the uplink feedback sent by the second UE may be similarly blocked from reaching the transmitting device.

[0143] The transmitting device may process any feedback during the second processing time 455. In some cases, the transmitting device may not be able to receive ACK messages and NACK messages from the first UE, or may not be able to receive or decode any feedback from the second UE. After processing the feedback from the UE, the transmitting device may prepare a control channel scheduling transmission including control channel resources 425 and corresponding data channel resources.

[0144] After the second processing time 455 ends, the transmitting device may retransmit data from the initial transmission that was not verified as successfully received. As described above, the retransmission may include control channel resources 425 to schedule data transmission during the corresponding data channel resources. In addition, the retransmission may be sent on the second transmit beam. The second UE may receive the control channel resources 425—for example, because the retransmission is sent on the backup transmit beam—and determine that the control information for the second UE is included in the control channel resources 425—for example, based on a blind decoding process. The second UE may then recognize that the data channel resources 430 are transmitting a retransmission of the data originally sent in the initial transmission 465 for the second UE. The second UE may then successfully receive and decode the data on the data channel resources 430. In some cases, the data channel resources 430 use the same amount of resources as the second UE resources 410. The first UE may similarly receive the control channel resources 425, but may determine that the data channel resources are not scheduled for the first UE.

[0145] At the end of the data channel resource, the second UE may process the data and take any indicated actions during a third processing time 460. The second UE may also generate feedback information to send to the transmitting device, including an ACK message and sensor measurements during the third processing time 460. After the end of the third processing time 460, the second UE may send an ACK message to the transmitting device on the third feedback resource.

[0146] The described communication resource structure can be repeated in previous and subsequent subframes, where an initial transmission can be sent on a first transmit beam during periodically scheduled resources and a retransmission can be sent on a second transmit beam during dynamically scheduled resources (e.g., resources scheduled by a control channel).

[0147] Figure 5 5 shows aspects of a process for switching to a backup beam according to various aspects of the various disclosures. Processing flow 500 may be performed by a base station 505, which may be as described in reference to Figures 1 to 3 Examples of base stations discussed; and UE 515, which may be as described above with reference to Figures 1 to 3 Examples of UEs described.

[0148] In some examples, the base station 505 and the UE 515 can perform a coordinated backup process from a main beam to a backup beam. In some cases, the base station 505 is a gNB including multiple transmission points, a gNB coupled to a PLC, or an independent PLC. In some cases, the UE 515 is a PLC or an S / A device.

[0149] At arrow 520, the base station 505 and the UE 515 may perform RRC signaling. In some cases, the UE 515 may indicate the ability to receive beamforming transmissions from multiple directions. In some cases, the base station 505 may indicate to the UE 515 the downlink resources that are periodically scheduled for the UE 515 to receive initial data transmissions. In some cases, the base station 505 and the UE 515 may use RRC signaling to configure URLLC between the base station 505 and the UE 515 - for example, if the base station 505 and the UE 515 operate in a factory setting (e.g., a manufacturing facility). In some cases, RRC signaling may be used to configure the UE 515 to receive and report CSI of multiple transmit beamforming transmissions sent by the base station 505.

[0150] At block 525, the UE 515 may identify the periodic downlink resources scheduled for the initial data transmission to the UE 515. Thus, the UE 515 may receive the initial data transmission during the scheduling interval without first decoding the control channel.

[0151] At block 530, the base station 505 may transmit multiple beamforming transmissions in multiple directions. In some cases, a beamforming transmission from the base station 505 that initially travels in a direction away from the UE 515 may be redirected toward the UE 515—for example, after reflecting off an object. In some cases, the base station 505 may transmit beamforming transmissions from multiple transmission points that are physically separated from one another. The UE 515 may receive all or a portion of the beamforming transmissions sent from the base station 505.

[0152] At arrow 535, UE 515 may send CSI for each of the beam scanning transmissions received from base station 505. In some cases, the CSI includes channel quality information, a rank indicator, and / or a precoding matrix. And base station 505 may receive CSI from UE 515.

[0153] At block 540, the base station 505 may identify primary and backup transmit beams for transmission to the UE 515 based on the reported CSI. In some cases, the primary transmit beam is reserved for initial data transmission to the UE 515 during periodically scheduled intervals. And the backup transmit beam is reserved for retransmitting data included in the initial data transmission during data resources (e.g., physical downlink shared channel (PDSCH) resources) scheduled by control channel (e.g., physical downlink control channel (PDCCH)) signaling.

[0154] To identify the primary and backup transmit beams, the base station 505 may perform calculations based on the transmitted transmit beams and the CSI received from the UE 515. For example, the base station 505 may identify the spatial diversity between each transmit beam, and may identify a transmit beam having a spatial diversity exceeding a threshold. In some examples, the spatial diversity between the transmit beams is identified by measuring the angular difference between the initial directions of the transmit beams. In some examples, the spatial diversity between the transmit beams is identified by determining that the transmit beams are from different transmission points. In some examples, the base station 505 selects the most uncoordinated transmit beams as the primary transmit beam and the backup transmit beam.

[0155] The base station 505 may also identify the channel quality of each transmit beam based on the reported CSI. The base station 505 may then select two or more transmit beams from the available transmit beams that satisfy the spatial diversity and channel quality thresholds. In some cases, the UE 515 may also identify the primary and backup transmit beams by performing the same or similar calculations as the base station 505.

[0156] At arrow 545, the base station 505 may indicate to the UE the primary and backup transmit beams selected by the base station 505. The base station 505 may then configure its antenna to perform a transmission in the direction of the primary transmit beam. The UE 515 may receive an indication of the primary transmit beam and the backup transmit beam and may configure its antenna to receive a transmission from the direction of the primary transmit beam. In some cases, the UE 115 may also configure its antenna to transmit an uplink transmission in the direction of the primary transmit beam. In some cases, the base station 505 may indicate the periodically scheduled resources for the UE 515 at arrow 545 instead of indicating the periodically scheduled resources in the RRC signaling.

[0157] In some examples, the base station 505 indicates both the main and backup transmit beams to the UE 515 in a control message (e.g., a downlink grant, a dynamic grant, a configured grant, an uplink grant, etc.). In some examples, the control message includes a field for indicating the main transmit beam for the scheduled initial transmission and another field for indicating the backup transmit beam for subsequent retransmissions that may occur. In other examples, the base station 505 indicates the main transmit beam and a table for determining the second transmit beam to the UE 515. The table may include a mapping between the indicated main transmit beam and the backup transmit beam—for example, the table may indicate that the backup transmit beam will be used for retransmission when the main transmit beam is indicated. The base station 505 can generate the table based on the CSI reported by the UE 515. The base station 505 can indicate (e.g., semi-statically) the table to the UE 515 in higher layer control signaling (e.g., RRC or MAC layer signaling). The base station 505 may also indicate (eg, dynamically) the primary transmit beam to the UE 515 in physical layer control signaling (eg, downlink control information (DCI) or other PDCCH signaling).

[0158] In some examples, the table is indicated on a semi-static basis, so the UE 515 can store and refer to the table until a new table (if applicable) is received from the base station 505. In this case, after receiving an indication of the main transmit beam, the UE 515 can refer to the entry in the table to obtain the main transmit beam corresponding to the backup transmit beam. The UE 515 can then determine that the main transmit beam is configured for initial transmission, while the backup transmit beam is configured for retransmission. The UE 515 may subsequently (e.g., after the operation described in block 590) receive additional indications of the main transmit beam from the base station 505, and may determine different backup transmit beams based on the indicated main transmit beam and the table.

[0159] At arrow 550, base station 505 may transmit an initial data transmission on the primary transmit beam during the scheduling interval. In some cases, a blocker may be in the path of the primary transmit beam, and UE 515 may be unable to receive the initial data transmission during the scheduling interval, or unable to decode the initial data transmission after receiving it.

[0160] At arrow 555, UE 515 may send a NACK message to base station 505 based on failure to receive or decode the initial data transmission during the scheduled resources. Base station 605 may receive and decode the NACK message from UE 515 and determine that the initial data transmission failed. In some cases, base station 505 does not receive the NACK message or fails to decode the NACK message—for example, if the NACK message is sent using the same path as the primary transmit beam.

[0161] At block 560, the base station 505 switches from the primary transmit beam to the backup transmit beam. To switch between the primary transmit beam and the backup transmit beam, the base station 505 may reconfigure its antenna to form the backup transmit beam.

[0162] In box 565, UE 515 can switch from the main receive beam corresponding to the main transmit beam to the backup receive beam corresponding to the main transmit beam. In order to switch between the main receive beam and the backup receive beam, UE 515 can reconfigure its antenna to form the backup receive beam. UE 515 can switch from the main receive beam to the backup receive beam at any time after failing to receive the initial data transmission - for example, before sending a NACK message. In some cases, UE 515 can also reconfigure its antenna to form a backup uplink transmit beam in the direction of the backup transmit beam. In other cases, UE 515 may not switch to the backup receive beam - for example, UE 515 can use a single antenna configuration to receive transmissions from base station 505.

[0163] At arrow 570, the base station 505 retransmits the data included in the failed initial data transmission on the backup transmit beam. In some cases, the base station 505 retransmits the data in the data resources scheduled by the control channel. The UE 515 can receive the backup transmission on the backup receive beam and can successfully decode the retransmission—e.g., due to the absence of blocking.

[0164] At block 575, the UE 515 analyzes the control channel resources in the retransmission to determine whether data transmission has been scheduled for the UE 515 in the corresponding data channel resources. In some examples, the UE 515 identifies its control channel resources based on a blind decoding process, and identifies the corresponding data channel resources based on the control information included in the identified control channel resources. After identifying its data channel resources, the UE 515 can decode the signals sent on the data channel resources to obtain the transmitted data. In some cases, the UE 515 performs an action based on the decoded data—for example, the UE 515 can actuate a motor and / or take sensor measurements.

[0165] At arrow 580, UE 515 sends a feedback message to base station 505. If UE 515 successfully decodes the data received in the retransmission, UE 515 may send an ACK message along with the measurement information to base station 505. If UE 515 fails to decode the data received in the retransmission, UE 515 may send a NACK message to base station 505. In some cases, UE 515 sends the feedback message on different resources than UE 515 sends the feedback message to the initial data transmission—for example, UE 515 may send the feedback message on different frequency resources or on a backup uplink transmit beam corresponding to the direction of the backup transmit beam.

[0166] At block 585, the base station 505 may switch back to the primary transmit beam before performing a subsequent initial data transmission. Meanwhile, at block 590, the UE 515 may switch back to the primary receive beam before the periodically scheduled resource occurs. In other cases, the UE 515 may not return to the primary receive beam—for example, the UE 515 may receive transmissions from the base station 505 using a single antenna configuration.

[0167] Thus, the base station 505 and the UE 515 may repeat the operations described starting with arrow 545. In some cases, the base station 505 and the UE 515 may successfully perform an initial data transmission after switching back to the primary transmit beam—for example, if the blockage in the primary transmit beam path has been removed. In other cases, subsequent initial data transmissions between the base station 505 and the UE 515 may continue to fail, and the base station 505 and the UE 515 may continue to fall back to their respective backup beams for retransmission of data, as described above. In some cases, the base station 505 may be triggered to perform another beam scanning process after a threshold number of transmission failures occur on the primary transmit beam within a specified interval—for example, if the blockage has not moved. After performing the additional beam scanning process, the base station 505 may identify new primary and secondary transmit beams for transmission to the UE 515, as discussed above.

[0168] In an alternative example, the initial data transmission to the UE 515 may be successful, but the base station 505 may not receive a corresponding ACK message from the UE 515. In some cases, the UE 515 may always switch to the backup receive beam after sending the feedback information, and thus may receive a retransmission from the base station 505. In other cases, the base station 505 may switch to the backup transmit beam, and the UE 515 may not switch to the backup receive beam, thereby reducing power consumption at the UE 515. In this case, the UE 515 may not receive a retransmission from the base station 505.

[0169] Although the above operations are discussed in the context of transmissions from the base station 505 to the UE 515, similar operations may be performed to support transmissions from the UE 515 to the base station 505. That is, the UE 515 may be configured to perform uplink transmissions on (in the directions of) the primary and secondary backup transmit beams identified by the base station 505. The base station 505 may similarly be configured to receive initial uplink transmissions on the primary transmit beam, report confirmation feedback of the uplink transmissions, and receive uplink retransmissions on the backup transmit beams.

[0170] Figure 6600 may be performed by a base station 505, which may be as described in reference to Figures 1 to 3 and Figure 5 An example of a base station discussed; PLC 610, which may be as described above with reference to Figure 1 and Figure 3 An example of a PLC as described above; and a UE 515, which may be as described above with reference to Figures 1 to 3 and Figure 5 Examples of UEs described.

[0171] In some examples, the PLC 610 and the UE 615 can perform a coordinated backup procedure from a primary beam to a backup beam during direct transmission between the PLC 610 and the UE 615. In some cases, the PLC 610 can rely on the base station 605 to perform management tasks such as scheduling resources and performing back-end calculations. In this case, the base station 605 can coordinate the backup procedure of the PLC 610 and the UE 615. In some cases, the UE 515 is a S / A device.

[0172] At arrow 620, the base station 605, PLC 610 and UE 615 can exchange RRC messages. In some cases, the PLC 610 and UE 615 indicate to the base station 605 the ability to communicate using beamforming transmission and / or to communicate directly with another UE on a D2D communication link (also referred to as side link communication). The PLC 610 and UE 615 can also indicate to the base station 605 the ability to use URLLC technology. The base station 605 can indicate to the PLC 610 and UE 615 that URLLC technology will be used for subsequent communications—for example, if the PLC 610 and UE 615 operate in a manufacturing facility. In some cases, the base station 605 can also indicate the periodic resources used for initial data transmission for communication between the PLC 610 and UE 615.

[0173] At block 625, the PLC 610 may identify periodic resources for performing an initial data transmission to the UE 615. Thus, the PLC 610 may perform the initial data transmission without using control channel resources to schedule the initial data transmission.

[0174] At block 630, the UE 615 may identify periodic resources for receiving the initial data transmission from the PLC 610. Thus, the UE 615 may receive the initial data transmission during the scheduling interval without first decoding the control channel.

[0175] At block 635, the PLC 610 may send multiple beamforming transmissions in multiple directions. In some cases, a beamforming transmission from the PLC 610 that was originally traveling in a direction away from the UE 615 may be redirected to the UE 615. The UE 615 may receive all or a portion of the beamforming transmission sent from the PLC 610. Additionally or alternatively, the base station 605 may perform a beam sweeping transmission. In this case, both the PLC 610 and the UE 615 may receive all or a portion of the beamforming transmission sent from the base station 605.

[0176] At arrow 640, UE 615 may report to base station 605 CSI for any beamforming transmissions received from PLC 610. In the event that base station 605 transmits beamforming transmissions, both UE 615 and PLC 610 may transmit CSI for any of the corresponding beamforming transmissions received.

[0177] At block 645, the base station 605 may identify primary and backup transmit beams for sidelink transmissions between the PLC 610 and the UE 615 based on the reported CSI. In some cases, the primary transmit beam is reserved for initial data transmissions from the PLC 610 to the UE 615 during periodic scheduled intervals. The backup transmit beam is reserved for retransmission of failed data included in the initial data transmission during data resources (e.g., sidelink shared channel (SDSCH) resources) scheduled by a control channel (e.g., sidelink control channel (SDCCH) resources).

[0178] To identify the primary transmit beam and the backup transmit beam, the base station 505 may perform calculations based on the transmitted transmit beam and the CSI received from the UE 615 and / or the PLC 610, as in Figure 5 540 of . For example, the base station 605 can identify the spatial diversity between the beamforming transmissions and select two or more transmit beams that meet the spatial diversity requirement. The base station 605 can also identify the channel quality of each transmit beam based on the reported CSI and identify the transmit beam that meets the channel quality threshold. The base station 605 can use both the calculated spatial diversity value and the channel quality information to select two or more transmit beams from the set of available transmit beams that meet the spatial diversity and channel quality thresholds. In some cases, the PLC 610 and the UE 615 can also identify the primary and backup transmit beams by performing the same or similar calculations as the base station 505.

[0179] At arrow 650, the base station 605 may indicate to the PLC 610 and the UE 615 the primary and backup transmit beams selected by the base station 605 for the sidelink communication between the PLC 610 and the UE 615. The PLC 610 may receive the indication of the primary transmit beam and the backup transmit beam and configure its antenna to transmit the sidelink communication in the direction of the primary transmit beam. Similarly, the UE 615 may receive the indication of the primary transmit beam and the backup transmit beam and configure its antenna to receive the sidelink transmission from the direction of the primary transmit beam. In some cases, the PLC 610 may also configure its antenna to receive the uplink sidelink transmission, and the UE 615 may also configure its antenna to transmit the uplink sidelink transmission in the direction of the main transmit beam. In some cases, the base station 605 may indicate the periodically scheduled resources for the PLC 610 and the UE 615 at arrow 650, instead of indicating the periodically scheduled resources in the RRC signaling.

[0180] In some examples, the base station 605 indicates both the main and backup transmit beams to the PLC 610 and / or the UE 615 in a control message (e.g., a downlink grant, a dynamic grant, a configured grant, an uplink grant, etc.). In some examples, the control message includes a field for indicating the main transmit beam for the scheduled initial transmission and another field for indicating the backup transmit beam for subsequent retransmissions that may occur. In other examples, the base station 605 indicates the main transmit beam and a table for determining the second transmit beam to the PLC 610 and / or the UE 615. The table may include a mapping between the indicated main transmit beam and the backup transmit beam—for example, the table may indicate that the backup transmit beam will be used for retransmission when the main transmit beam is indicated. The base station 605 and / or the PLC 610 may generate a table based on the CSI reported by the UE 615. The base station 605 may indicate (e.g., semi-statically) the table to the PLC 610 and / or the UE 615 in higher layer control signaling (e.g., RRC or MAC layer signaling). In some examples, the PLC 610 indicates the table to the UE 615 using higher layer control signaling. The base station 605 may also indicate (e.g., dynamically) the primary transmit beam to the PLC 610 and / or the UE 615 in physical layer control signaling (e.g., DCI or other PDCCH signaling). In some examples, the PLC 610 indicates the primary transmit beam to the UE 615 using physical layer control signaling.

[0181] In some examples, the table is indicated on a semi-static basis, so the PLC 610 and / or UE 615 can store and refer to the table until a new table (if applicable) is received from the base station 605. In this case, after receiving an indication of the main transmit beam, the PLC 610 and / or UE 615 can refer to the entry in the table to obtain the main transmit beam corresponding to the backup transmit beam. The PLC 610 and / or UE 615 can then determine that the main transmit beam is configured for initial transmission, while the backup transmit beam is configured for retransmission. The UE 615 may subsequently (e.g., after the operation described in block 695) receive additional indications of the main transmit beam from the base station 605, and may determine different backup transmit beams based on the indicated main transmit beam and the table.

[0182] PLC 610 may transmit an initial sidelink data transmission on the primary transmit beam at arrow 655. In some cases, a blocker may be in the path of the primary transmit beam and UE 615 may be unable to receive the initial data transmission during the scheduling interval or be unable to decode the initial data transmission after reception.

[0183] At arrow 660, UE 615 may send a NACK message to PLC 610 based on failure to receive or decode the initial data transmission during the scheduled resources. PLC 610 may receive and decode the NACK message from UE 615 and determine that the initial data transmission failed. In some cases, PLC 610 does not receive the NACK message or fails to decode the NACK message—for example, if the NACK message is sent using the same path as the primary transmit beam.

[0184] At block 665, the PLC 610 switches from the primary transmit beam to the backup transmit beam. To switch between the primary transmit beam and the backup transmit beam, the PLC 610 may reconfigure its antenna to form the backup transmit beam. In some cases, the PLC 610 also reconfigures its antenna to form a backup uplink receive beam corresponding to the backup uplink transmit beam formed by the antenna at the UE 615.

[0185] In box 670, UE 615 can switch from the main receive beam corresponding to the main transmit beam to the backup receive beam corresponding to the main transmit beam. In order to switch between the main receive beam and the backup receive beam, UE 615 can reconfigure its antenna to form a backup receive beam. UE 615 can switch from the main receive beam to the backup receive beam at any time after failing to receive the initial data transmission - for example, before sending a NACK message. In some cases, UE 615 reconfigures its antenna to form a backup uplink transmit beam in the direction of the backup transmit beam. In other cases, UE515 may not switch to the backup receive beam - for example, UE 515 can use a single antenna configuration to receive transmissions from base station 505.

[0186] At arrow 675, PLC 610 retransmits the data included in the failed initial data transmission on the backup transmit beam. In some cases, PLC 610 retransmits the data in the data resources scheduled by the control channel. UE 615 may receive the backup transmission on the backup receive beam and may successfully decode the retransmission—e.g., due to the absence of blocking.

[0187] At block 680, UE 615 analyzes the control channel resources in the retransmission to determine whether data transmission has been scheduled for UE 615 in the corresponding data channel resources. In some examples, UE 615 identifies its control channel resources based on a blind decoding process, and identifies the corresponding data channel resources based on control information included in the identified control channel resources. After identifying its data channel resources, UE 615 can decode the signals sent on the data channel resources to obtain the transmitted data. In some cases, UE 615 performs an action based on the decoded data—for example, UE 615 can actuate a motor and / or take sensor measurements.

[0188] At arrow 685, UE 615 sends a feedback message to PLC 610. If UE 615 successfully decodes the data received in the retransmission, UE 615 may send an ACK message along with the measurement information to PLC 610. If UE 615 fails to decode the data received in the retransmission, UE 615 may send a NACK message to PLC 610. In some cases, UE 615 sends the feedback message on different resources than UE 615 sends the feedback message to the initial data transmission—for example, UE 615 may send the feedback message on different frequency resources or on a backup uplink transmit beam corresponding to the direction of the backup transmit beam.

[0189] At block 690, the PLC 610 may switch back to the primary transmit beam before performing a subsequent initial data transmission on the sidelink. Meanwhile, at block 695, the UE 615 may switch back to the primary receive beam before the periodically scheduled resource occurs. In other cases, the UE 515 may not return to the primary receive beam—for example, the UE 515 may receive transmissions from the base station 505 using a single antenna configuration.

[0190] Thus, the PLC 610 and UE 615 may repeat the operations described starting from arrow 650. In some cases, the PLC 610 and UE 615 may successfully perform initial data transmission after switching back to the primary transmit beam on the side link—for example, if the blockage in the primary transmit beam path has been removed. In other cases, subsequent initial data transmissions between the PLC 610 and UE 615 may continue to fail, and the PLC 610 and UE 615 may continue to fall back to their respective backup beams for retransmission of data, as described above. In some cases, the PLC 610 may be triggered to perform another beam scanning process after a threshold number of transmission failures occur on the primary transmit beam within a specified interval—for example, if the blockage has not moved. After performing the additional beam scanning process, the base station 605 may identify new primary and secondary transmit beams for transmission between the PLC 610 and UE 615, as discussed above.

[0191] Although the above operations are discussed in the context of transmissions from the PLC 610 to the UE 515, similar operations may be performed to support transmissions from the UE 515 to the PLC 610 and / or the base station 505. That is, the UE 515 may be configured to perform uplink transmissions on (in the directions of) the primary and secondary backup transmit beams identified by the base station 505 and / or the PLC 610. The base station 505 and / or the PLC 610 may similarly be configured to receive initial uplink transmissions on the primary transmit beam, report confirmation feedback of the uplink transmission, and receive uplink retransmissions on the backup transmit beams.

[0192] Figure 7 A block diagram of a device supporting switching to a backup beam according to various aspects of the present disclosure is shown. Block diagram 700 may provide a representation of a device 705. Device 705 may be an example of aspects of a UE or PLC as described herein. Device 705 may include a receiver 710, a UE communication manager 715, and a transmitter 720. Device 705 may also include a processor. Each of these components may communicate with each other (e.g., via one or more buses).

[0193] The receiver 710 may receive information such as packets, user data, or control information associated with various information channels (e.g., control channels, data channels, and information related to switching to backup beams, etc.). The information may be passed to other components of the device 705. The receiver 710 may be a reference Fig. 9 Examples of aspects of the transceiver 915 are described. The receiver 710 may utilize a single antenna or a collection of antennas.

[0194] In some cases, the UE communication manager 715 may be implemented in a UE that communicates directly with a base station. In this case, the UE communication manager 715 may receive a set of transmit beams and report the CSI of the set of transmit beams. The UE communication manager 715 may also receive an indication of a first transmit beam of the set of transmit beams based on the reported CSI, wherein the first transmit beam is configured to transmit an initial transmission to the UE. The UE communication manager 715 may also identify a second transmit beam in the set of transmit beams based on the indication, wherein the second transmit beam is configured to transmit a retransmission to the UE. In some cases, the UE communication manager 715 may fail to receive or decode a first transmission of user data on a first transmit beam during a first interval, and may send a negative acknowledgement (NACK) message based on the failure to receive or decode the first transmission. The UE communication manager 715 may receive a second transmission of user data on a second transmit beam during a subsequent interval.

[0195] In some cases, the UE communication manager 715 may receive a set of transmit beams and report the CSI of the set of transmit beams. The UE communication manager 715 may also receive an indication of a first transmit beam of the set of transmit beams based on the reported CSI, wherein the first transmit beam is configured to transmit an initial transmission to the UE. The UE communication manager 715 may also identify a second transmit beam in the set of transmit beams based on the indication, wherein the second transmit beam is configured to transmit a retransmission to the UE. The UE communication manager 715 may also send a first transmission of user data on the first transmit beam during a first interval. In some cases, the UE communication manager 715 may receive a negative acknowledgement (NACK) message based on the first transmission. The UE communication manager 715 may send a second transmission of user data on the second transmit beam during a subsequent interval based on receiving the NACK message.

[0196] In some cases, the UE communication manager 715 may be implemented in a UE that communicates directly with other UEs with the assistance of a base station. In this case, the UE communication manager 715 may send a set of transmit beams. The UE communication manager 715 may also receive an indication of a first transmit beam in the set of transmit beams from the base station based on CSI reported by the second UE to the base station, wherein the first transmit beam is configured to transmit an initial transmission from the first UE to the second UE. The UE communication manager 715 may also identify a second transmit beam in the set of transmit beams based on the indication, wherein the second transmit beam is configured to transmit a retransmission from the first UE to the second UE. The UE communication manager 715 may send a first transmission of user data to the second UE on the first transmit beam during a first interval. In some cases, the UE communication manager 715 may fail to receive or decode an acknowledgment (ACK) message in response to the first transmission, and may send a second transmission of user data to the second UE on the second transmit beam during a subsequent interval based on the failure to receive or decode the ACK message.

[0197] The UE communication manager 715 or its subcomponents may be implemented by hardware, code executed by a processor (e.g., software or firmware), or any combination thereof. If implemented in code executed by a processor, the functions of the communication manager 715 or its subcomponents may be performed by a general purpose processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described in the present disclosure.

[0198] The UE communication manager 715 or its subcomponents can be physically located in various locations, including being distributed so that portions of the functionality are implemented by one or more physical components at different physical locations. In some examples, the UE communication manager 715 or its subcomponents can be independent and distinct components according to various aspects of the present disclosure. In some examples, the UE communication manager 715 or its subcomponents can be combined with one or more other hardware components, including but not limited to input / output (I / O) components, transceivers, network servers, another computing device, one or more other components described in the present disclosure, or combinations thereof according to various aspects of the present disclosure.

[0199] Transmitter 720 can transmit signals generated by other components of device 705. In some examples, transmitter 720 can be co-located with receiver 710 in a transceiver component. For example, transmitter 720 can be a reference Fig. 9 Examples of aspects of the transceiver 915 are described. The transmitter 720 may utilize a single antenna or a collection of antennas.

[0200] Figure 8A block diagram of a device supporting switching to a backup beam according to various aspects of the present disclosure is shown. Block diagram 800 may provide a representation of a device 805. Device 805 may be an example of aspects of device 705, UE, or PLC as described herein. Device 805 may include a receiver 810, a UE communication manager 815, and a transmitter 845. Device 805 may also include a processor. Each of these components may communicate with each other (e.g., via one or more buses).

[0201] The receiver 810 may receive information such as packets, user data, or control information associated with various information channels (e.g., control channels, data channels, and information related to switching to backup beams, etc.). The information may be communicated to other components of the device 805. The receiver 810 may be a reference Fig. 9 Examples of aspects of the transceiver 915 are described. The receiver 810 may utilize a single antenna or a collection of antennas.

[0202] The UE communication manager 815 may be an example of aspects of the UE communication manager 715 as described herein. The UE communication manager 815 may include a CSI component 820, a backup component 825, a data manager 830, a feedback component 835, and a beam manager 840. The UE communication manager 815 may be an example of aspects of the communication manager 910 described herein.

[0203] In some cases, the UE communication manager 815 may be implemented in a UE that communicates directly with a base station and may operate as follows.

[0204] In some cases, the beam manager 840 may receive a set of transmit beams. The CSI component 820 may report the CSI for the set of transmit beams.

[0205] The backup component 825 may receive an indication of a first transmit beam of the transmit beam set based on the reported CSI, wherein the first transmit beam is configured to transmit an initial transmission to the UE. The backup component 825 may also identify a second transmit beam in the transmit beam set based on the indication, wherein the second transmit beam is configured to transmit a retransmission to the UE. In some cases, the indication indicates a second transmit beam. In some cases, receiving an indication of the first transmit beam and the second transmit beam includes receiving a control message including a first field for indicating a first transmit beam for the first transmission and a second field for indicating a second transmit beam for the second transmission. In other cases, identifying the second transmit beam includes determining a mapping between the first transmit beam and the second transmit beam based at least in part on a table. In some cases, the table may be stored at the device 805. In some examples, the backup component 825 may switch from a first receive beam corresponding to the first transmit beam to a second receive beam corresponding to the second transmit beam based on sending a NACK message.

[0206] During the first interval, the data manager 830 may be unable to receive or decode the first transmission of user data on the first transmit beam. In some examples, the data manager 830 receives an indication of a set of periodic intervals during which the UE is scheduled to receive an initial transmission of user data, wherein the set of periodic intervals includes the first interval.

[0207] Feedback component 835 can send a negative acknowledgement (NACK) message based on a failure to receive or decode the first transmission.

[0208] In some examples, the data manager 830 may receive a second transmission of the user data on the second transmit beam during a subsequent interval. In some examples, the data manager 830 receives the second transmission of the user data during a subsequent interval based on receiving control information in the control channel indicating a location of the user data in the data channel.

[0209] In some cases, the UE communication manager 715 may be implemented in a UE that communicates directly with other UEs with the assistance of a base station, and may operate as follows.

[0210] In some cases, the beam manager 840 may transmit a set of transmit beams. In some examples, the backup component 825 may receive an indication of a first transmit beam in the set of transmit beams from the base station based on CSI reported by the second UE to the base station, wherein the first transmit beam is configured to transmit an initial transmission from the first UE to the second UE. The backup component 825 may also identify a second transmit beam in the set of transmit beams based on the indication, wherein the second transmit beam is configured to transmit a retransmission from the first UE to the second UE. In some examples, the backup component 825 may switch from the first transmit beam to the second transmit beam based on a failure to receive or decode an ACK message.

[0211] In some examples, the data manager 830 may send a first transmission of user data to the second UE on the first transmit beam during the first interval. In some examples, the data manager 830 sends an indication of a set of periodic intervals during which the second UE is scheduled to receive the initial transmission of user data, wherein the set of periodic intervals includes the first interval.

[0212] In some examples, feedback component 835 may be unable to receive or decode an acknowledgement (ACK) message in response to the first transmission.

[0213] In some examples, the data manager 830 may, based on failing to receive or decode the ACK message, send a second transmission of the user data to the second UE on the second transmit beam during a subsequent interval. In some examples, the data manager 830 sends the second transmission of the user data during a subsequent interval based on sending control information in the control channel indicating the location of the user data in the data channel.

[0214] Transmitter 845 can transmit signals generated by other components of device 805. In some examples, transmitter 845 can be co-located with transceiver components in receiver 810. For example, transmitter 845 can be a reference Fig. 9 Examples of aspects of the transceiver 915 are described. The transmitter 845 may utilize a single antenna or a collection of antennas.

[0215] Fig. 9 A diagram of a system including a device supporting switching to a backup beam according to various aspects of the present disclosure is shown. System 900 may include device 905. Device 905 may be an example of or include components of device 705, device 805, or UE 115 as described herein. Device 905 may include components for two-way voice and data communications, including components for sending and receiving communications, including UE communication manager 910, transceiver 915, antenna 920, memory 925, and processor 935. These components may communicate electronically via one or more buses (e.g., bus 940).

[0216] The UE communication manager 910 may be an example of the UE communication manager 715 or the UE communication manager 815 .

[0217] The transceiver 915 can communicate bidirectionally via one or more antennas, wired or wireless links as described above. For example, the transceiver 915 can represent a wireless transceiver and can communicate bidirectionally with another wireless transceiver. The transceiver 915 can also include a modem for modulating packets and providing the modulated packets to an antenna for transmission, and demodulating packets received from an antenna.

[0218] In some cases, a wireless device may include a single antenna 920. However, in some cases, a device may have more than one antenna 920, which may be capable of sending or receiving multiple wireless transmissions simultaneously.

[0219] The memory 925 may include random access memory (RAM) and read-only memory (ROM). The memory 925 may store computer-readable computer executable code 930, which includes instructions that, when executed, cause the processor to perform various functions described herein. In some cases, the memory 925 may contain a basic input / output system (BIOS), etc., which may control basic hardware or software operations, such as interaction with peripheral components or devices.

[0220] The code 930 may include instructions to implement aspects of the present disclosure, including instructions to support wireless communications. The code 930 may be stored in a non-transitory computer-readable medium such as a system memory or other type of memory. In some cases, the code 930 may not be directly executed by the processor 935, but may cause a computer (e.g., when compiled and executed) to perform the functions described herein.

[0221] The processor 935 may include an intelligent hardware device (e.g., a general purpose processor, a DSP, a CPU, a microcontroller, an ASIC, an FPGA, a programmable logic device, discrete gate or transistor logic components, discrete hardware components, or any combination thereof). In some cases, the processor 935 may be configured to operate a memory array using a memory controller. In other cases, the memory controller may be integrated into the processor 935. The processor 935 may be configured to execute computer-readable instructions stored in a memory (e.g., memory 925) to cause the device 905 to perform various functions (e.g., functions or tasks that support switching to a backup beam).

[0222] Fig.10 A block diagram of a device supporting switching to a backup beam according to various aspects of the present disclosure is shown. Block diagram 1000 may represent device 1005. Device 1005 may be an example of aspects of a base station or PLC as described herein. Device 1005 may include a receiver 1010, a base station communication manager 1015, and a transmitter 1020. Device 1005 may also include a processor. Each of these components may communicate with each other (e.g., via one or more buses).

[0223] The receiver 1010 may receive information such as packets, user data, or control information associated with various information channels (e.g., control channels, data channels, and information related to switching to backup beams, etc.). The information may be communicated to other components of the device 1005. The receiver 1010 may be a reference Fig.12 Examples of aspects of the transceiver 1220 are described. The receiver 1010 may utilize a single antenna or a collection of antennas.

[0224] The base station communication manager 1015 may send a set of transmit beams. The base station communication manager 1015 may also receive CSI for the set of transmit beams, the CSI including CSI reported by the UE, and may identify a first transmit beam and a second transmit beam of the set of transmit beams based on the CSI. The base station communication manager 1015 may send an indication of a first transmit beam to the UE based on the reported CSI, wherein the first transmit beam is configured to transmit an initial transmission to the UE, and the second transmit beam is configured to transmit a retransmission to the UE. The base station communication manager 1015 may also send a first transmission of user data to the UE on the first transmit beam during a first interval. In some cases, the base station communication manager 1015 may fail to receive or decode an acknowledgment (ACK) message in response to the first transmission, and may send a second transmission of user data to the UE on the second transmit beam during a subsequent interval based on the failure to receive or decode the ACK message.

[0225] The base station communication manager 1015 or its subcomponents may be implemented by hardware, code (e.g., software or firmware) executed by a processor, or any combination thereof. If implemented in code executed by a processor, the functions of the base station communication manager 1015 or its subcomponents may be performed by a general purpose processor, a DSP, an application specific integrated circuit (ASIC), an FPGA or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described in the present disclosure.

[0226] The base station communication manager 1015 or its subcomponents can be physically located in various locations, including being distributed so that portions of the functionality are implemented by one or more physical components at different physical locations. In some examples, the base station communication manager 1015 or its subcomponents can be independent and distinct components according to various aspects of the present disclosure. In some examples, the base station communication manager 1015 or its subcomponents can be combined with one or more other hardware components, including but not limited to input / output (I / O) components, transceivers, network servers, another computing device, one or more other components described in the present disclosure, or combinations thereof according to various aspects of the present disclosure.

[0227] Transmitter 1020 can transmit signals generated by other components of device 1005. In some examples, transmitter 1020 can be co-located with receiver 1010 in a transceiver assembly. For example, transmitter 1020 can be a reference Fig.12 Examples of aspects of the transceiver 1220 are described. The transmitter 1020 may utilize a single antenna or a collection of antennas.

[0228] Fig.11A block diagram of a device supporting switching to a backup beam according to various aspects of the present disclosure is shown. Block diagram 1100 may represent device 1105. Device 1105 may be an example of aspects of device 1005, a base station, or a PLC as described herein. Device 1105 may include a receiver 1110, a base station communication manager 1115, and a transmitter 1145. Device 1105 may also include a processor. Each of these components may communicate with each other (e.g., via one or more buses).

[0229] The receiver 1110 may receive information such as packets, user data, or control information associated with various information channels (e.g., control channels, data channels, and information related to switching to backup beams, etc.). The information may be communicated to other components of the device 1105. The receiver 1110 may be a reference Fig.12 Examples of aspects of transceiver 1220 are described. Receiver 1110 may utilize a single antenna or a collection of antennas.

[0230] The base station communication manager 1115 may be an example of aspects of the base station communication manager 1015 as described herein. The base station communication manager 1115 may include a base station beam manager 1120, a base station CSI component 1125, a base station backup component 1130, a base station data manager 1135, and a base station feedback component 1140. The base station communication manager 1115 may be an example of aspects of the base station communication manager 1210 described herein.

[0231] The base station beam manager 1120 may transmit a transmit beam set. In some examples, the base station beam manager 1120 transmits a first transmit beam in the transmit beam set from a first TRP and transmits a second transmit beam from a second TRP.

[0232] The base station CSI component 1125 may receive CSI for the set of transmit beams, the CSI including CSI reported by the UE. When the device 1105 is configured to use a base station to perform PLC scheduling tasks, the base station CSI component 1125 may receive CSI reported by the UE from the base station, and may receive CSI including CSI reported by a second UE. In some examples, the base station CSI component 1125 generates a table providing a mapping between a primary transmit beam and a backup transmit beam based at least in part on the CSI.

[0233] The base station backup component 1130 may identify the first transmit beam and the second transmit beam in the transmit beam set based on the CSI. In some examples, the base station backup component 1130 may send an indication of the first transmit beam to the UE based on the reported CSI, wherein the first transmit beam is configured to transmit an initial transmission to the UE and the second transmit beam is configured to transmit a retransmission to the UE. When the device 1105 is configured to use a base station to perform a PLC scheduling task, the base station backup component 1130 may identify the first transmit beam and the second transmit beam based on receiving an indication of the first transmit beam from the base station. In some examples, the indication indicates the second transmit beam—for example, the indication of the first transmit beam may be indicated in a first field of a DCI message, and the indication of the second transmit beam may be indicated in a second field of the DCI message. In other examples, the base station backup component 1130 sends the table to the UE, wherein the table includes a mapping between the first transmit beam and the second transmit beam.

[0234] In some examples, the base station backup component 1130 may calculate a set of spatial diversity values ​​between the transmit beams of the transmit beam set. In some examples, the base station backup component 1130 may select the first transmit beam and the second transmit beam based on determining that the spatial diversity value calculated between the first transmit beam and the second transmit beam exceeds a threshold. In some examples, the base station backup component 1130 may calculate a set of channel quality values ​​for the transmit beam set based on the CSI reported by the UE, wherein calculating the set of spatial diversity values ​​includes calculating the set of spatial diversity values ​​between the transmit beams of a subset of the transmit beam set having channel quality values ​​exceeding a second threshold, wherein the subset of the transmit beam set includes the first transmit beam and the second transmit beam. When the device 1105 is configured to use the PLC of the base station to perform scheduling tasks, the base station backup component 1130 may send a second indication of a first transmit beam and a second transmit beam to the second UE based on the reported CSI, wherein the first transmit beam is configured to transmit an initial transmission from the second UE to the UE, and the second transmit beam is configured to transmit a retransmission from the second UE to the UE.

[0235] The base station data manager 1135 may send a first transmission of user data to the UE on the first transmit beam during the first interval. In some examples, the base station data manager 1135 may send an indication of a set of periodic intervals during which the UE is scheduled to receive the initial transmission of user data, wherein the set of periodic intervals includes the first interval.

[0236] The base station feedback component 1140 fails to receive or decode an acknowledgement (ACK) message in response to the first transmission.

[0237] The base station data manager 1135 may, based on failing to receive or decode the ACK message, send a second transmission of the user data to the UE on the second transmit beam during a subsequent interval. In some examples, the base station data manager 1135 may send the second transmission of the user data during a subsequent interval based on sending control information in the control channel indicating the location of the user data in the data channel.

[0238] Transmitter 1145 can transmit signals generated by other components of device 1105. In some examples, transmitter 1145 can be co-located with receiver 1110 in a transceiver component. For example, transmitter 1145 can be a reference Fig.12 Examples of aspects of the transceiver 1220 are described. The transmitter 1145 may utilize a single antenna or a collection of antennas.

[0239] Fig.12 A diagram of a system including a device supporting switching to a backup beam according to various aspects of the present disclosure is shown. System 1200 may include device 1205. Device 1205 may be an example of or include components of device 1005, device 1105, or base station 105 as described herein. Device 1205 may include components for two-way voice and data communications, including components for sending and receiving communications, including a base station communication manager 1210, a network communication manager 1215, a transceiver 1220, an antenna 1225, a memory 1230, a processor 1240, and an inter-station communication manager 1245. These components may communicate electronically via one or more buses (e.g., bus 1250).

[0240] The base station communication manager 1210 may be an example of the base station communication manager 1015 or the base station communication manager 1115 .

[0241] The network communications manager 1215 may manage communications with the core network (eg, via one or more wired backhaul links). For example, the network communications manager 1215 may manage the delivery of data communications for client devices such as one or more UEs 115.

[0242] The transceiver 1220 may communicate bidirectionally via one or more antennas, wired or wireless links as described above. For example, the transceiver 1220 may represent a wireless transceiver and may communicate bidirectionally with another wireless transceiver. The transceiver 1220 may also include a modem for modulating packets and providing the modulated packets to an antenna for transmission, and demodulating packets received from an antenna.

[0243] In some cases, a wireless device may include a single antenna 1225. However, in some cases, a device may have more than one antenna 1225, which may be capable of sending or receiving multiple wireless transmissions simultaneously.

[0244] The memory 1230 may include RAM and ROM. The memory 1230 may store computer-readable computer executable code 1235, which includes instructions that, when executed, cause the processor to perform various functions described herein. In some cases, the memory 1230 may contain BIOS, etc., which may control basic hardware or software operations, such as interaction with peripheral components or devices.

[0245] The code 1235 may include instructions to implement aspects of the present disclosure, including instructions to support wireless communications. The code 1235 may be stored in a non-transitory computer-readable medium such as a system memory or other type of memory. In some cases, the code 1235 may not be directly executed by the processor 1240, but may cause a computer (e.g., when compiled and executed) to perform the functions described herein.

[0246] Processor 1240 may include an intelligent hardware device (e.g., a general purpose processor, a DSP, a CPU, a microcontroller, an ASIC, an FPGA, a programmable logic device, discrete gate or transistor logic components, discrete hardware components, or any combination thereof). In some cases, processor 1240 may be configured to operate a memory array using a memory controller. In other cases, the memory controller may be integrated into processor 1240. Processor 1240 may be configured to execute computer-readable instructions stored in a memory (e.g., memory 1230) to cause device 1205 to perform various functions (e.g., functions or tasks that support switching to a backup beam).

[0247] The inter-site communication manager 1245 may manage communications with other base stations 105 and may include a controller or scheduler for controlling communications with UE 115 in collaboration with other base stations 105. For example, the inter-site communication manager 1245 may coordinate scheduling of transmissions to UE 115 for various interference mitigation techniques such as beamforming or joint transmission. In some examples, the inter-site communication manager 1245 may provide an X2 interface within an LTE / LTE-A wireless communication network technology to provide communications between base stations 105.

[0248] Fig.13 A flow chart illustrating a method for supporting switching to a backup beam according to various aspects of the present disclosure is shown. The operations of method 1300 may be implemented by UE 115 or a component thereof, as described herein. For example, the operations of method 1300 may be performed by a communication manager, as described in reference to Figures 7 to 9 In some examples, the UE may execute a set of instructions to control the functional elements of the UE to perform the described functions. Additionally or alternatively, the UE may use dedicated hardware to perform aspects of the described functions.

[0249] At 1305, the UE may receive multiple transmit beams. The operations of 1305 may be performed according to the methods described herein. In some examples, aspects of the operations of 1305 may be described with reference to Figures 7 to 9 The beam manager is used to perform the

[0250] At 1310, the UE may report channel state information (CSI) for multiple transmit beams. The operations of 1310 may be performed according to the methods described herein. In some examples, aspects of the operations of 1310 may be described with reference to Figures 7 to 9 The CSI component is used to perform the

[0251] At 1315, the UE may receive an indication of a first transmit beam in the plurality of transmit beams based at least in part on the reported CSI, wherein the first transmit beam is configured to transmit an initial transmission to the UE. The operations of 1315 may be performed according to the methods described herein. In some examples, aspects of the operations of 1315 may be as described with reference to Figures 7 to 9 The fallback component is used to execute.

[0252] At 1320, the UE may identify a second transmit beam in the plurality of transmit beams based at least in part on the indication, wherein the second transmit beam is configured to transmit a retransmission to the UE. The operations of 1320 may be performed according to the methods described herein. In some examples, aspects of the operations of 1320 may be as described with reference to Figures 7 to 9 The fallback component is used to execute.

[0253] At 1325, during the first interval, the UE may be unable to receive or decode the first transmission of user data on the first transmit beam. The operations of 1325 may be performed according to the methods described herein. In some examples, aspects of the operations of 1325 may be described with reference to Figures 7 to 9 The data manager is executed.

[0254] At 1330, the UE may send a negative acknowledgement (NACK) message based at least in part on a failure to receive or decode the first transmission. The operations of 1330 may be performed according to the methods described herein. In some examples, aspects of the operations of 1330 may be described with reference to Figures 7 to 9 The feedback component is executed.

[0255] At 1335, the UE may receive a second transmission of user data on a second transmit beam during a subsequent interval. The operations of 1335 may be performed according to the methods described herein. In some examples, aspects of the operations of 1335 may be described with reference to Figures 7 to 9 The data manager is executed.

[0256] Fig.14A flow chart illustrating a method for supporting switching to a backup beam according to various aspects of the present disclosure is shown. The operations of method 1400 may be implemented by base station 105 or components thereof, as described herein. For example, the operations of method 1400 may be performed by a communication manager, as described in reference to Figure 10 to Figure 12 In some examples, the base station may execute a set of instructions to control functional elements of the base station to perform the described functions. Additionally or alternatively, the base station may use dedicated hardware to perform aspects of the described functions.

[0257] At 1405, the base station may transmit a plurality of transmit beams. The operations of 1405 may be performed according to the methods described herein. In some examples, aspects of the operations of 1405 may be described with reference to Figures 10 to 12 The beam manager is used to perform the

[0258] At 1410, a base station may receive channel state information (CSI) for a plurality of transmit beams, the CSI including CSI reported by a user equipment (UE). The operations of 1410 may be performed according to the methods described herein. In some examples, aspects of the operations of 1410 may be described with reference to Figures 10 to 12 The CSI component is used to perform the

[0259] At 1415, the base station may identify a first transmit beam and a second transmit beam in the plurality of transmit beams based at least in part on the CSI. The operations of 1415 may be performed according to the methods described herein. In some examples, aspects of the operations of 1415 may be as described in reference to Figure 10 to Figure 12 The fallback component is used to execute.

[0260] At 1420, the base station may send an indication of a first transmit beam to the UE based at least in part on the reported CSI, wherein the first transmit beam is configured to transmit an initial transmission to the UE and the second transmit beam is configured to transmit a retransmission to the UE. The operations of 1420 may be performed according to the methods described herein. In some examples, aspects of the operations of 1420 may be as described in reference to Figure 10 to Figure 12 The fallback component is used to execute.

[0261] At 1425, the base station may transmit a first transmission of user data to the UE on a first transmit beam during a first interval. The operations of 1425 may be performed according to the methods described herein. In some examples, aspects of the operations of 1425 may be described with reference to Figures 10 to 12 The data manager is executed.

[0262] At 1430, the base station fails to receive or decode an acknowledgment (ACK) message in response to the first transmission. The operations of 1430 may be performed according to the methods described herein. In some examples, aspects of the operations of 1430 may be described with reference to Figures 10 to 12The feedback component is executed.

[0263] At 1435, the base station may, based on the failure to receive or decode the ACK message, transmit a second transmission of user data to the UE on the second transmit beam during a subsequent interval. The operations of 1435 may be performed according to the methods described herein. In some examples, aspects of the operations of 1435 may be described with reference to Figures 10 to 12 The data manager is executed.

[0264] Fig.15 A flow chart illustrating a method for supporting switching to a backup beam according to various aspects of the present disclosure is shown. The operations of method 1500 may be implemented by UE 115 or a component thereof, as described herein. For example, the operations of method 1500 may be performed by a communication manager, as described in reference to Figures 7 to 9 In some examples, the UE may execute a set of instructions to control the functional elements of the UE to perform the described functions. Additionally or alternatively, the UE may use dedicated hardware to perform aspects of the described functions.

[0265] At 1505, the UE may transmit a plurality of transmit beams. The operations of 1505 may be performed according to the methods described herein. In some examples, aspects of the operations of 1505 may be described with reference to Figures 7 to 9 The beam manager is used to perform the

[0266] At 1510, the UE may receive an indication of a first transmit beam in a plurality of transmit beams from a base station based at least in part on channel state information (CSI) reported by a second UE to the base station, wherein the first transmit beam is configured to transmit an initial transmission from the first UE to the second UE. The operations of 1510 may be performed according to the methods described herein. In some examples, aspects of the operations of 1510 may be as described in reference to Figures 7 to 9 The fallback component is used to execute.

[0267] At 1515, the UE may identify a second transmit beam in the plurality of transmit beams based at least in part on the indication, wherein the second transmit beam is configured to transmit the retransmission from the first UE to the second UE. The operations of 1515 may be performed according to the methods described herein. In some examples, aspects of the operations of 1515 may be as described with reference to Figures 7 to 9 The fallback component is used to execute.

[0268] At 1520, the UE may transmit a first transmission of user data to a second UE on a first transmit beam during a first interval. The operations of 1520 may be performed according to the methods described herein. In some examples, aspects of the operations of 1520 may be described with reference to Figures 7 to 9 The data manager is executed.

[0269] At 1525, the UE fails to receive or decode an acknowledgment (ACK) message in response to the first transmission. The operations of 1525 may be performed according to the methods described herein. In some examples, aspects of the operations of 1525 may be described with reference to Figures 7 to 9 The feedback component is executed.

[0270] At 1530, the UE may, based at least in part on the failure to receive or decode the ACK message, transmit a second transmission of user data to the second UE on the second transmit beam during a subsequent interval. The operations of 1530 may be performed according to the methods described herein. In some examples, aspects of the operations of 1530 may be described with reference to Figures 7 to 9 The data manager is executed.

[0271] Fig.16 A flow chart illustrating a method for supporting switching to a backup beam according to various aspects of the present disclosure is shown. The operations of method 1600 may be implemented by UE 115 or a component thereof, as described herein. For example, the operations of method 1600 may be performed by a communication manager, as described in reference to Figures 7 to 9 In some examples, the UE may execute a set of instructions to control the functional elements of the UE to perform the described functions. Additionally or alternatively, the UE may use dedicated hardware to perform aspects of the described functions.

[0272] At 1605, the UE may receive multiple transmit beams. The operations of 1605 may be performed according to the methods described herein. In some examples, aspects of the operations of 1605 may be described with reference to Figures 7 to 9 The beam manager is used to perform the

[0273] At 1610, the UE may report channel state information (CSI) for multiple transmit beams. The operations of 1610 may be performed according to the methods described herein. In some examples, aspects of the operations of 1610 may be described with reference to Figures 7 to 9 The CSI component is used to perform the

[0274] At 1615, the UE may receive an indication of a first transmit beam in the plurality of transmit beams based at least in part on the reported CSI, wherein the first transmit beam is configured to transmit an initial transmission to the UE. The operations of 1615 may be performed according to the methods described herein. In some examples, aspects of the operations of 1615 may be as described with reference to Figures 7 to 9 The fallback component is used to execute.

[0275] At 1620, the UE may identify a second transmit beam in the plurality of transmit beams based at least in part on the indication, wherein the second transmit beam is configured to transmit a retransmission to the UE. The operations of 1620 may be performed according to the methods described herein. In some examples, aspects of the operations of 1620 may be as described in reference to Figures 7 to 9 The fallback component is used to execute.

[0276] At 1625, the UE may transmit a first transmission of user data on a first transmit beam during a first interval. The operations of 1625 may be performed according to the methods described herein. In some examples, aspects of the operations of 1625 may be described with reference to Figures 7 to 9 The data manager is executed.

[0277] At 1630, the UE may receive a negative acknowledgement (NACK) message based at least in part on the first transmission. The operations of 1630 may be performed according to the methods described herein. In some examples, aspects of the operations of 1630 may be described with reference to Figures 7 to 9 The feedback component is executed.

[0278] At 1635, the UE may transmit a second transmission of user data on the second transmit beam during a subsequent interval based at least in part on receiving the NACK message. The operations of 1635 may be performed according to the methods described herein. In some examples, aspects of the operations of 1635 may be described with reference to Figures 7 to 9 The data manager is executed.

[0279] It should be noted that the methods described herein describe possible implementations, and that operations and steps may be rearranged or otherwise modified, and other implementations are possible. Furthermore, aspects from two or more methods may be combined.

[0280] Although aspects of LTE, LTE-A, LTE-A Pro, or NR systems may be described for purposes of example, and LTE, LTE-A, LTE-A Pro, or NR terminology may be used in much of the description, the techniques described herein are applicable to applications beyond LTE, LTE-A, LTE-A Pro, or NR networks. For example, the described techniques may be applicable to various other wireless communication systems, such as Ultra Mobile Broadband (UMB), Institute of Electrical and Electronics Engineers (IEEE) 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, Flash-OFDM, and other systems and radio technologies not explicitly mentioned herein.

[0281] The information and signals described herein may be represented using any of a variety of different technologies and techniques. For example, data, instructions, commands, information, signals, bits, symbols, and chips that may be referenced throughout the description may be represented by voltage, current, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof.

[0282] The various illustrative blocks and components described in conjunction with the disclosure herein may be implemented or executed using a general purpose processor, a DSP, an ASIC, a CPU, an FPGA or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general purpose processor may be a microprocessor, but in an alternative, the processor may be any conventional processor, controller, microcontroller, or state machine. The processor may also be implemented as a combination of computing devices, for example, a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in combination with a DSP core, or any other such configuration.

[0283] The functions described herein may be implemented in hardware, software executed by a processor, firmware, or any combination thereof. If implemented in software executed by a processor, the functions may be stored or transmitted on a computer-readable medium as one or more instructions or codes. Other examples and implementations are within the scope of this disclosure and the appended claims. For example, due to the nature of software, the functions described herein may be implemented using software executed by a processor, hardware, firmware, hard wiring, or any combination of these. Features that implement the functions may also be physically located in various locations, including being distributed so that portions of the functions are implemented in different physical locations.

[0284] Computer readable medium includes both non-transitory computer storage medium and communication medium, and computer storage medium and communication medium include any medium that helps to transfer computer program from one place to another place.Non-transitory storage medium can be any available medium that can be accessed by general or special-purpose computer.As an example and not limitation, non-transitory computer readable medium can include RAM, ROM, electrically erasable programmable ROM (EEPROM), flash memory, CD (CD) ROM or other optical disk storage, disk storage or other magnetic storage device or can be used for carrying or storing required program code mode in the form of instruction or data structure and can be accessed by general or special-purpose computer or general or special-purpose processor Any other non-transitory medium.In addition, any connection is appropriately referred to as computer readable medium.For example, if coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL) or wireless technology (such as infrared, radio and microwave) are used to send software from website, server or other remote source, coaxial cable, fiber optic cable, twisted pair, DSL or wireless technology (such as infrared, radio and microwave) are included in the definition of computer readable medium. Disk and disc, as used herein, includes CD, laser disc, optical disc, digital versatile disc (DVD), floppy disk and Blu-ray disc, where disks usually reproduce data magnetically, while discs reproduce data optically with lasers. Combinations of the above are also included within the scope of computer-readable media.

[0285] As used herein, including in the claims, "or" as used in a list of items (e.g., a list of items preceded by a phrase such as "at least one" or "one or more"), indicates an inclusive list, so that, for example, a list of at least one of A, B, or C means A or B or C or AB or AC or BC or ABC (i.e., A and B and C). In addition, as used herein, the phrase "based on" should not be interpreted as a reference to a closed set of conditions. For example, an example step described as "based on condition A" can be based on both condition A and condition B without departing from the scope of this disclosure. In other words, as used herein, the phrase "based on" should be interpreted in the same manner as the phrase "based at least in part on."

[0286] In the drawings, similar components or features may have the same reference label. In addition, various components of the same type may be distinguished by following the reference label with a dash and a second label that distinguishes between similar components. If only the first reference label is used in the specification, the specification applies to any one similar component having the same first reference label, regardless of the second reference label or other subsequent reference labels.

[0287] The descriptions set forth herein in conjunction with the accompanying drawings describe example configurations and do not represent all examples that may be implemented or within the scope of the claims. The term "example" as used herein means "used as an example, instance, or illustration," rather than "preferred" or "superior to other examples." For the purpose of providing an understanding of the described technology, the detailed description includes specific details. However, the technologies may be practiced without these specific details. In some cases, in order to avoid obscuring the concepts of the described examples, known structures and devices are shown in block diagram form.

[0288] The description provided herein enables those skilled in the art to make or use the present disclosure. Various modifications to the present disclosure will be apparent to those skilled in the art, and the general principles defined herein may be applied to other variations without departing from the scope of the present disclosure. Therefore, the present disclosure is not limited to the examples and designs described herein, but conforms to the broadest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for wireless communication at a first user equipment UE, comprising: receiving a plurality of transmit beams from a second UE; Reporting channel state information CSI of the multiple transmit beams to a base station; receiving, from the base station, an indication of a first transmit beam of the plurality of transmit beams based at least in part on the reported CSI, wherein the first transmit beam is configured to convey an initial transmission from the second UE to the first UE; identifying a second transmit beam of the plurality of transmit beams based at least in part on the indication, wherein the second transmit beam is configured to convey a retransmission from the second UE to the first UE; After identifying the second transmit beam, during a first interval, failing to receive or decode a first transmission of user data transmitted via the first transmit beam, wherein the first transmission is the initial transmission; sending a negative acknowledgement (NACK) message based at least in part on a failure to receive or decode the first transmission; switching to the second transmit beam in response to a failure to receive or decode the first transmission; as well as A second transmission of the user data is received via the second transmit beam during a subsequent interval, wherein the second transmission is the retransmission.

2. The method according to claim 1, further comprising: Switching from a first receive beam corresponding to the first transmit beam to a second receive beam corresponding to the second transmit beam is performed in response to a failure to receive or decode the first transmission.

3. The method according to claim 1, further comprising: An indication of a plurality of periodic intervals is received during which the first UE is scheduled to receive an initial transmission of user data, wherein the plurality of periodic intervals includes the first interval.

4. The method of claim 1, wherein receiving the second transmission of the user data during the subsequent interval comprises receiving control information in a control channel indicating a location of the user data in a data channel. The method of claim 1 , wherein a spatial diversity between the first transmit beam and the second transmit beam exceeds a threshold. The method of claim 1 , wherein the indication further indicates the second transmit beam.

7. The method of claim 6, wherein receiving the indication of the first transmit beam and the second transmit beam comprises receiving a control message comprising a first field for indicating the first transmit beam used for the first transmission and a second field for indicating the second transmit beam used for the second transmission.

8. The method of claim 1 , wherein identifying the second transmit beam comprises: A mapping between the first transmit beam and the second transmit beam is determined based at least in part on a table.

9. A method for wireless communication at a base station, comprising: receiving, from the first user equipment UE, channel state information CSI of a plurality of transmit beams transmitted by the second UE; identifying a first transmit beam and a second transmit beam of the plurality of transmit beams based at least in part on the CSI; transmitting an indication of the first transmit beam to the first UE and the second UE based at least in part on the CSI, wherein the first transmit beam is configured to transmit an initial transmission from the second UE to the first UE and the second transmit beam is configured to transmit a retransmission from the second UE to the first UE, wherein, during the first interval, the second UE transmits a first transmission of user data to the first UE via the first transmit beam, wherein the first transmission is the initial transmission; and Wherein, after identifying the second transmit beam, the second UE switches to the second transmit beam in response to failing to receive or decode an acknowledgment ACK message for the first transmission, and during a subsequent interval, sends a second transmission of the user data to the first UE via the second transmit beam at least in part based on the failure to receive or decode the ACK message, wherein the second transmission is the retransmission.

10. The method according to claim 9, further comprising: calculating a plurality of spatial diversity values ​​between the transmission beams of the plurality of transmission beams; as well as The first transmit beam and the second transmit beam are selected based at least in part on determining that a spatial diversity value calculated between the first transmit beam and the second transmit beam exceeds a threshold.

11. The method according to claim 10, further comprising: and calculating a plurality of channel quality values ​​for the plurality of transmit beams based at least in part on the CSI reported by the first UE, wherein calculating the plurality of spatial diversity values ​​comprises: The plurality of spatial diversity values ​​between the transmission beams of a subset of the plurality of transmission beams having channel quality values ​​exceeding a second threshold are calculated, wherein the subset of the plurality of transmission beams includes the first transmission beam and the second transmission beam.

12. The method according to claim 9, further comprising: An indication of a plurality of periodic intervals is sent during which the first UE is scheduled to receive an initial transmission of user data, wherein the plurality of periodic intervals includes the first interval.

13. The method of claim 9, further comprising sending control information in a control channel indicating a location of the user data in a data channel.

14. The method of claim 9, wherein a spatial diversity between the first transmit beam and the second transmit beam exceeds a threshold. The method of claim 9 , wherein the indication further indicates the second transmit beam.

16. The method according to claim 9, further comprising: generating a table providing a mapping between a primary transmit beam and a backup transmit beam based at least in part on the CSI; as well as The table is sent to the first UE, wherein the table includes a mapping between the first transmit beam and the second transmit beam.

17. A method for wireless communication at a second user equipment UE, comprising: Sending a plurality of transmit beams to a first UE; receiving, from a base station, an indication of a first transmit beam of the plurality of transmit beams, the indication being based at least in part on channel state information (CSI) of the plurality of transmit beams reported by the first UE to the base station, wherein the first transmit beam is configured to transmit an initial transmission from the second UE to the first UE; identifying a second transmit beam of the plurality of transmit beams based at least in part on the indication, wherein the second transmit beam is configured to convey a retransmission from the second UE to the first UE; During a first interval, transmitting a first transmission of user data via the first transmit beam, wherein the first transmission is the initial transmission; After identifying the second transmit beam, receiving a negative acknowledgement (NACK) message based at least in part on the first transmission; switching to the second transmit beam in response to receiving the NACK message; as well as During a subsequent interval, based at least in part on receiving the NACK message, transmitting a second transmission of the user data via the second transmit beam, wherein the second transmission is the retransmission. The method of claim 17 , wherein the indication further indicates the second transmit beam.

19. The method of claim 17, wherein identifying the second transmit beam comprises: A mapping between the first transmit beam and the second transmit beam is determined based at least in part on a table.

20. An apparatus for wireless communication, the apparatus comprising a processor, a memory coupled to the processor, and instructions stored in the memory, wherein the instructions are executable by the processor to cause the apparatus to perform the method of claim 1, 9 or 17.

21. An apparatus for wireless communication comprising means for performing the steps of the method of claim 1, 9 or 17.

22. A non-transitory computer readable medium storing code for wireless communication, the code comprising instructions executable by a processor to perform the method of claim 1, 9 or 17.

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