Feedback for multicast communications

Abstract

Methods, systems, and devices for wireless communication that support feedback for multicast communications are described. A user equipment (UE) in a group of UEs may receive multicast information from a base station in a downlink (DL) transmission scheduled by a DL grant. The DL grant may also indicate a set of uplink resources for the group of UEs to use to transmit feedback. The UE may attempt to decode messages containing multicast information in the DL transmission. If the UE determines that the message is successfully decoded, the UE may not send feedback to the base station. If the UE determines that the message has not been successfully decoded, the UE may send a feedback message to the base station to indicate that the message has not been successfully decoded. The base station may monitor the feedback message and determine to retransmit the multicast information if the feedback message is received.

Description

[0001] This application is a divisional application of Chinese invention patent application 202080031939.8 (PCT / US2020 / 031129) with a filing date of May 1, 2020 and entitled “Feedback for Multicast Communications”. Technical Field

[0002] The following relates generally to wireless communications, and more particularly to feedback for multicast communications. Background Art

[0003] Wireless communication systems are widely deployed to provide various types of communication content, such as voice, video, packet data, messaging, broadcasting, etc. These systems may be able to 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, advanced LTE (LTE-A) systems, or LTE-A Pro systems), and fifth generation (5G) systems that may be referred to as new radio (NR) systems. These systems may use various technologies, 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 several base stations or network access nodes, each of which simultaneously supports the communication of multiple communication devices, which may be referred to as user equipment (UE).

[0004] A wireless multiple access communication system may support multicast communication with UEs, wherein the system transmits information to multiple UEs simultaneously. The system may use a base station associated with the system to transmit information. The base station may transmit the multicast information to all UEs in a cell, or the base station may transmit the information to a group of UEs in a cell. Summary of the invention

[0005] The described technology relates to improved methods, systems, devices and apparatuses for supporting feedback for multicast communications. In general, the described technology provides a user equipment (UE) to provide feedback to a base station after receiving multicast information. UEs in a UE group can receive multicast information from a base station in a DL transmission scheduled by a downlink (DL) grant. The DL grant may also indicate an uplink (UL) resource set used by the UE group to transmit feedback. The UE may attempt to decode a message containing multicast information in the DL transmission. If the UE determines that the message is successfully decoded, the UE may not send feedback to the base station. If the UE determines that the message is not successfully decoded, the UE may send a feedback message to the base station to indicate that the message is not successfully decoded. The base station may monitor the feedback message and determine to retransmit the multicast information if the feedback message is received.

[0006] A method of wireless communication at a UE is described. The method may include receiving a DL grant from a base station, the DL grant indicating a DL resource set for DL ​​transmission to a set of UEs including the UE; identifying a UL resource set for negative acknowledgement feedback information corresponding to the DL transmission based on the DL grant; monitoring the DL resource set for DL ​​transmission from the base station; and transmitting a feedback message to the base station via the UL resource set based on the monitoring, wherein the feedback message indicates that reception of the DL transmission was unsuccessful.

[0007] An apparatus for wireless communication at a UE is described. The apparatus may include a processor, a memory in electronic communication with the processor, and instructions stored in the memory. The instructions are executable by the processor to cause the apparatus to: receive a DL grant from a base station, the DL grant indicating a DL resource set for DL ​​transmission to a set of UEs including the UE; identify a UL resource set for negative acknowledgement feedback information corresponding to the DL transmission based on the DL grant; monitor the DL resource set for DL ​​transmission from the base station; and transmit a feedback message to the base station via the UL resource set based on the monitoring, wherein the feedback message indicates that reception of the DL transmission was unsuccessful.

[0008] Another apparatus for wireless communication at a UE is described. The apparatus may include means for receiving a DL grant from a base station, the DL grant indicating a DL resource set for a DL transmission to a set of UEs including the UE; means for identifying a UL resource set for negative acknowledgement feedback information corresponding to the DL transmission based on the DL grant; means for monitoring the DL resource set for a DL transmission from the base station; and means for transmitting a feedback message to the base station via the UL resource set based on the monitoring, wherein the feedback message indicates that reception of the DL transmission was unsuccessful.

[0009] 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 DL grant from a base station, the DL grant indicating a DL resource set for DL ​​transmission to a set of UEs including the UE; identify a UL resource set for negative acknowledgement feedback information corresponding to the DL transmission based on the DL grant; monitor the DL resource set for DL ​​transmission from the base station; and transmit a feedback message to the base station via the UL resource set based on the monitoring, wherein the feedback message indicates that reception of the DL transmission was unsuccessful.

[0010] Some examples of the methods, devices (apparatus), and non-transitory computer-readable media described herein may further include operations, features, means, or instructions for the following actions: receiving the DL grant via the DL transmit beam configured for the set of UEs.

[0011] Some examples of the methods, devices (apparatus), and non-transitory computer-readable media described herein may further include operations, features, apparatus, or instructions for the following actions: receiving one or more additional DL grants via corresponding DL transmit beams, wherein each additional DL grant indicates a corresponding additional DL resource set for DL ​​transmission; identifying an additional UL resource set for negative acknowledgment feedback information corresponding to the DL transmission based on the one or more additional DL grants; and monitoring the additional DL resource set for DL ​​transmission from a base station.

[0012] Some examples of the methods, devices (apparatus), and non-transitory computer-readable media described herein may further include operations, features, apparatuses, or instructions for the following actions: transmitting an additional feedback message to a base station via a corresponding UL resource set based on monitoring an additional DL resource set, wherein the additional feedback message indicates that reception of the DL transmission was unsuccessful.

[0013] Some examples of the methods, devices (apparatus), and non-transitory computer-readable media described herein may further include operations, features, apparatuses, or instructions for: combining information received via an additional DL resource set based on the monitoring; determining that reception of a DL transmission is unsuccessful based on the combination; and transmitting a feedback message set including the feedback message on a corresponding UL resource set for negative acknowledgement feedback information.

[0014] Some examples of the methods, devices (apparatus), and non-transitory computer-readable media described herein may further include operations, features, apparatus, or instructions for: measuring the link quality of a UL transmit beam set configured for communicating with a base station; and transmitting a feedback message based on the link quality via at least one UL transmit beam in the UL transmit beam set.

[0015] Some examples of the methods, devices (apparatus), and non-transitory computer-readable media described herein may further include operations, features, apparatuses, or instructions for the following actions: determining that a decoding procedure for DL ​​transmission is unsuccessful based on the monitoring; and transmitting a feedback message based on determining that a decoding procedure for DL ​​transmission is unsuccessful.

[0016] Some examples of the methods, devices (apparatus), and non-transitory computer-readable media described herein may further include operations, features, apparatus, or instructions for the following actions: receiving a second DL grant from a base station, the second DL grant indicating a second DL resource set for retransmitting a DL transmission to the UE in response to a feedback message; and monitoring the second DL resource set to look for retransmissions of the DL transmission.

[0017] Some examples of the methods, devices (apparatus) and non-transitory computer-readable media described herein may further include operations, features, apparatuses or instructions for the following actions: transmitting a second feedback message to a base station based on monitoring a second UL resource set indicated by a second DL grant for negatively acknowledging feedback information, wherein the feedback message indicates that reception of a retransmission was unsuccessful.

[0018] In some examples of the methods, devices (apparatus), and non-transitory computer-readable media described herein, the UL resource set includes a physical uplink control channel (PUCCH), a physical uplink shared channel (PUSCH), a random access channel (RACH), UL resources within the system bandwidth, UL resources outside the system bandwidth, or any combination thereof.

[0019] Some examples of the methods, devices (apparatus), and non-transient computer-readable media described herein may further include operations, features, devices, or instructions for the following actions: receiving a DL grant via a physical downlink control channel (PDCCH). In some examples of the methods, devices (apparatus), and non-transient computer-readable media described herein, monitoring a DL resource set may include operations, features, devices, or instructions for monitoring a physical downlink shared channel (PDSCH) to find DL transmissions. In some examples of the methods, devices (apparatus), and non-transient computer-readable media described herein, the feedback message includes a hybrid automatic repeat request (HARQ) negative acknowledgment (NACK) message, a bit sequence, a message preamble, or a combination thereof.

[0020] In some examples of the methods, devices (apparatus), and non-transitory computer-readable media described herein, the DL grant includes a feedback timing indicator indicating a UL resource set. In some examples of the methods, devices (apparatus), and non-transitory computer-readable media described herein, the feedback timing indicator includes a PDSCH to HARQ feedback timing indicator. In some examples of the methods, devices (apparatus), and non-transitory computer-readable media described herein, the UL resource indicator includes a PUCCH resource indicator. In some examples of the methods, devices (apparatus), and non-transitory computer-readable media described herein, the UL resource indicator and the feedback timing indicator may be included in downlink control information (DCI) containing the DL grant.

[0021] A method of wireless communication at a base station is described. The method may include determining a DL resource set for a DL transmission to a set of UEs; determining a UL resource set for negative acknowledgement feedback information corresponding to the DL transmission; transmitting a DL grant to the set of UEs, the DL grant indicating the DL resource set for the DL transmission and the UL resource set for negative acknowledgement feedback information corresponding to the DL transmission; and monitoring the UL resource set for a feedback message from at least one UE in the set of UEs, wherein the feedback message indicates that reception of the DL transmission at the at least one UE was unsuccessful.

[0022] An apparatus for wireless communication at a base station is described. The apparatus may include a processor, a memory in electronic communication with the processor, and instructions stored in the memory. The instructions are executable by the processor to cause the apparatus to: determine a DL resource set for a DL transmission to a set of UEs; determine a UL resource set for negative acknowledgment feedback information corresponding to the DL transmission; transmit a DL grant to the set of UEs, the DL grant indicating the DL resource set for the DL transmission and the UL resource set for negative acknowledgment feedback information corresponding to the DL transmission; and monitor the UL resource set for a feedback message from at least one UE in the set of UEs, wherein the feedback message indicates that reception of the DL transmission at the at least one UE was unsuccessful.

[0023] Another apparatus for wireless communication at a base station is described. The apparatus may include means for determining a DL resource set for a DL transmission to a set of UEs; means for determining a UL resource set for negative acknowledgement feedback information corresponding to the DL transmission; means for transmitting a DL grant to the set of UEs, the DL grant indicating the DL resource set for the DL transmission and the UL resource set for negative acknowledgement feedback information corresponding to the DL transmission; and means for monitoring the UL resource set for a feedback message from at least one UE in the set of UEs, wherein the feedback message indicates that reception of the DL transmission at the at least one UE was unsuccessful.

[0024] A non-transitory computer-readable medium storing code for wireless communication at a base station is described. The code may include instructions executable by a processor to: determine a DL resource set for a DL transmission to a set of UEs; determine a UL resource set for negative acknowledgement feedback information corresponding to the DL transmission; transmit a DL grant to the set of UEs, the DL grant indicating the DL resource set for the DL transmission and the UL resource set for negative acknowledgement feedback information corresponding to the DL transmission; and monitor the UL resource set for a feedback message from at least one UE in the set of UEs, wherein the feedback message indicates that reception of the DL transmission at the at least one UE was unsuccessful.

[0025] Some examples of the methods, devices (apparatus), and non-transitory computer-readable media described herein may further include operations, features, apparatus, or instructions for the following actions: determining a DL transmit beam set configured for the UE set, and transmitting the DL grant to the UE set via one or more DL transmit beams in the DL transmit beam set.

[0026] Some examples of the methods, devices (apparatus), and non-transitory computer-readable media described herein may further include operations, features, apparatus, or instructions for the following actions: transmitting one or more additional DL grants via corresponding DL transmit beams, wherein each additional DL grant indicates a corresponding DL resource set for the DL transmission and a corresponding UL resource set for negative acknowledgment feedback information corresponding to the DL transmission.

[0027] Some examples of the methods, devices (apparatus), and non-transitory computer-readable media described herein may further include operations, features, apparatus, or instructions for the following actions: monitoring a corresponding UL resource set for a feedback message from at least one UE, wherein the feedback message indicates that reception of the DL transmission via the one or more DL transmit beams at the at least one UE is unsuccessful.

[0028] Some examples of the methods, devices (apparatus), and non-transitory computer-readable media described herein may further include operations, features, apparatus, or instructions for the following actions: receiving the feedback message from the at least one UE based on monitoring the UL resource set; and transmitting a second DL grant to the UE set, the second DL grant indicating a second DL resource set for retransmitting the DL transmission in response to the feedback message and a second UL resource set for negative acknowledgment feedback information corresponding to the retransmission.

[0029] Some examples of the methods, devices (apparatus), and non-transitory computer-readable media described herein may further include operations, features, apparatus, or instructions for the following actions: identifying a DL transmit beam and DL resources corresponding to a UL resource on which a feedback message from at least one UE can be received, and transmitting a second DL grant via the DL transmit beam and DL resources.

[0030] In some examples of the methods, devices (apparatus), and non-transitory computer-readable media described herein, the UL resource set includes PUCCH, PUSCH, RACH, UL resources within the system bandwidth, UL resources outside the system bandwidth, or any combination thereof.

[0031] Some examples of the methods, devices (apparatus), and non-transitory computer-readable media described herein may further include operations, features, means, or instructions for the following actions: determining, for each UE in the set of UEs, a corresponding UL resource set for negative acknowledgement feedback information corresponding to a DL transmission, wherein the DL grant indicates these corresponding UL resource sets. In some examples of the methods, devices (apparatus), and non-transitory computer-readable media described herein, at least two of the corresponding UL resource sets at least partially overlap.

[0032] Some examples of the methods, devices (apparatus), and non-transitory computer-readable media described herein may further include operations, features, apparatus, or instructions for determining a common sequence and common time and frequency resource mapping for a set of UEs, and transmitting an indication of the common sequence and common time and frequency resource mapping to the set of UEs.

[0033] In some examples of the methods, devices (apparatus), and non-transient computer-readable media described herein, the DL grant includes a UL resource indicator and a feedback timing indicator indicating a UL resource set. In some examples of the methods, devices (apparatus), and non-transient computer-readable media described herein, the feedback timing indicator includes a PDSCH to HARQ feedback timing indicator. In some examples of the methods, devices (apparatus), and non-transient computer-readable media described herein, the UL resource indicator includes a PUCCH resource indicator. Some examples of the methods, devices (apparatus), and non-transient computer-readable media described herein may further include operations, features, devices, or instructions for the following actions: transmitting a DCI to the UE set, the DCI including the UL resource indicator and the feedback timing indicator. In some examples of the methods, devices (apparatus), and non-transient computer-readable media described herein, transmitting the DL grant may include operations, features, devices, or instructions for transmitting the DL grant in a PDCCH.

[0034] Some examples of the methods, devices (apparatus), and non-transient computer-readable media described herein may further include operations, features, means, or instructions for transmitting DL transmissions in PDSCH. In some examples of the methods, devices (apparatus), and non-transient computer-readable media described herein, the feedback message includes a NACK message. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figures 1 to 3

[0013] An example of a wireless communication system supporting feedback for multicast communications in accordance with aspects of the present disclosure is illustrated.

[0036] Figure 4 and 5

[0013] An example of a transmission timeline supporting feedback for multicast communications in accordance with aspects of the present disclosure is illustrated.

[0037] Figure 6 An example of a process flow for supporting feedback for multicast communications in accordance with aspects of the present disclosure is illustrated.

[0038] Figure 7 and 8 A block diagram of an apparatus supporting feedback for multicast communications in accordance with aspects of the present disclosure is shown.

[0039] Fig. 9 A block diagram of a communications manager supporting feedback for multicast communications in accordance with aspects of the present disclosure is shown.

[0040] Fig.10 A diagram of a system including devices supporting feedback for multicast communications is shown in accordance with aspects of the present disclosure.

[0041] Fig.11 and 12 A block diagram of an apparatus supporting feedback for multicast communications in accordance with aspects of the present disclosure is shown.

[0042] Fig.13 A block diagram of a communications manager supporting feedback for multicast communications in accordance with aspects of the present disclosure is shown.

[0043] Fig.14 A diagram of a system including devices supporting feedback for multicast communications is shown in accordance with aspects of the present disclosure.

[0044] Figures 15 to 21 A flow chart illustrating a method of supporting feedback for multicast communications in accordance with aspects of the present disclosure is shown. DETAILED DESCRIPTION

[0045] A wireless communication network may support multicast communications with user equipment (UE), wherein the network transmits information to multiple UEs on a multicast channel. The network may use a base station associated with the network to transmit the information. The base station may transmit the multicast information to all UEs in a cell, or the base station may transmit the information to a group of UEs in a cell. The base station may determine the group of UEs based on location, device type, mobility, etc.

[0046] Supporting or responding to feedback from UEs that receive multicast information may be challenging for a base station. For example, if feedback for multicast transmissions is supported, multiple UEs in a cell may attempt to transmit feedback concurrently to confirm that the multicast information was received or to report that the reception or decoding of the multicast information was unsuccessful. This concurrent feedback transmission may result in conflicts or congestion of uplink (UL) resources and increased system overhead for the base station and the network. In addition, the network may transmit the multicast information a single time (i.e., without repetitions), and therefore a group of UEs may not be able to combine repeated transmissions to improve decoding reliability.

[0047] Provided herein are techniques for supporting feedback for multicast communications. A UE in a UE group may receive multicast information from a base station in a DL transmission scheduled by a downlink (DL) grant. The UE may attempt to decode a message containing the multicast information in the DL transmission. If the UE determines that the message is successfully decoded, the UE may not send feedback to the base station. If the UE determines that the message is not successfully decoded, the UE may send a negative acknowledgement (NACK) feedback to the base station to indicate that the message is not successfully decoded.

[0048] The DL grant may also indicate a UL resource set for the UE group to transmit NACK feedback. The UL resource set may include time and frequency resources in which the UE group can transmit NACK feedback to the base station. Each UE in the UE group may be directed to use the UL resources in the UL resource set, and the UL resources for each UE may at least partially overlap. After transmitting the DL grant and DL transmission, the base station may monitor the indicated UL resource set to find NACK feedback. If the base station receives NACK feedback from at least one UE in the UE group in the indicated UL resource set, the base station may determine to retransmit the multicast information to the UE group in a subsequent DL transmission scheduled by the DL grant.

[0049] In some examples, such as in millimeter wave (mmW) applications, a base station may transmit multicast information in a beam sweeping procedure. The multicast information may be transmitted via multiple DL transmit beams (e.g., in a time division multiplexing (TDM) configuration). The base station may transmit a DL grant via each DL transmit beam, wherein each DL grant schedules a corresponding DL transmission and a corresponding UL resource set for NACK feedback. In some examples, each UL resource set may have a spatial relationship with an associated DL transmit beam, i.e., a UL transmission on the UL resource set may be transmitted on a UL transmit beam associated with the DL transmit beam. In some examples, such as when there is a correspondence between a DL transmit beam and a UL receive beam, the base station may receive NACK feedback for multicast information transmitted via the DL transmit beam via the corresponding UL receive beam. In some examples, such as when there is a correspondence between a UL transmit beam and a DL receive beam, the UE may transmit NACK feedback for multicast information received via the DL receive beam via the corresponding UL transmit beam.

[0050] The beam sweeping procedure may allow a UE to receive repetitions of multicast information via multiple DL transmit beams. Each DL transmit beam may be associated with a UE subgroup, and a given UE may belong to multiple UE subgroups. The UE may receive DL transmissions scheduled by its corresponding DL grants via multiple DL transmit beams. The UE may combine DL transmissions before attempting to decode the message to improve decoding reliability. If the UE does not successfully decode the message even after combining, the UE may transmit NACK feedback in the UL resources indicated by one or more of these DL grants. In some examples, the UE may transmit NACK feedback in the UL resources indicated by multiple DL grants. In other examples, the UE may transmit NACK feedback in the UL resources indicated by a single DL grant, where the UE determines which UL resources to use based on link quality (e.g., the UE may transmit NACK feedback in the UL resources associated with the strongest link quality). The base station may monitor the UL resources indicated by each DL grant, and determine to retransmit the multicast information in the DL resources via the DL transmit beams corresponding to those UL resources in which NACK feedback is received.

[0051] The UE may transmit NACK feedback using UL resources as indicated by the DL grant. In some examples, the UE may use UL resources as indicated in a physical downlink shared channel (PDSCH) to hybrid automatic repeat request (HARQ) feedback timing indicator or a physical uplink control channel (PUSCH) resource indicator, such as resources identified in a PDSCH to HARQ feedback timing indicator field or a PUCCH resource indicator field in DL control information (DCI) in a physical downlink control channel (PDCCH) containing the DL grant. The PDSCH to HARQ feedback timing indicator or the PUCCH resource indicator may indicate UL resources that the UE may use to transmit HARQ feedback for unicast information, and the UE may use the same UL resources to transmit NACK feedback for multicast information. In some examples, the UL resources used to transmit NACK feedback may be included in the following: PUCCH, a physical uplink shared channel (PUSCH), a random access channel (RACH), or other resources configured and / or indicated within or outside the system bandwidth, or a combination thereof.

[0052] In some examples, the UE may transmit NACK feedback in the following: a HARQ NACK message, a special bit sequence (e.g., a bit sequence unique to NACK feedback or other feedback messages), a message preamble, or a combination thereof. In some examples, the UE may transmit NACK feedback based on a single frequency network (SFN) configuration. The UE group may use a common waveform, a common sequence, a common resource mapping, or a combination thereof to transmit NACK feedback. The base station may determine that NACK feedback is received from at least one UE in the UE group, and in some cases, it may not be identified how many UEs or which UEs in the UE group transmit NACK feedback. In response to the received NACK feedback, the base station may perform a retransmission of the multicast information (e.g., via a different transmit beam or using different DL resources).

[0053] Various aspects of the present disclosure are initially described in the context of a wireless communication system. Additional examples of transmission timelines and process flows are then discussed. Various aspects of the present disclosure are further illustrated and described by and with reference to apparatus diagrams, system diagrams, and flow charts related to feedback for multicast communications.

[0054] Figure 1An example of a wireless communication system 100 supporting feedback for multicast communications in accordance with various aspects of the present disclosure is illustrated. The wireless communication system 100 includes 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 advanced LTE (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, or communications with low-cost and low-complexity devices.

[0055] The base station 105 may communicate wirelessly with the UE 115 via one or more base station antennas. The base station 105 described herein may include or may be referred to by those skilled in the art as a base transceiver station, a radio base station, an access point, a radio transceiver, a Node B, an evolved Node B (eNB), a next generation Node B, or a Gigabit Node B (any of which may be referred to as a gNB), a Home Node B, a Home Evolved Node B, or some other suitable terminology. The wireless communication system 100 may include different types of base stations 105 (e.g., macro cell base stations or small cell base stations). The UE 115 described herein may be able to communicate with various types of base stations 105 and network equipment (including macro eNBs, small cell eNBs, gNBs, relay base stations, etc.).

[0056] Each base station 105 may be associated with a particular geographic coverage area 110 in which it supports communications with various UEs 115. Each base station 105 may provide communications coverage for a corresponding geographic coverage area 110 via a communications link 125, and the communications link 125 between the base station 105 and the UE 115 may utilize one or more carriers. The communications link 125 shown in the wireless communication system 100 may include a UL transmission from the UE 115 to the base station 105, or a DL transmission from the base station 105 to the UE 115. DL transmissions may also be referred to as forward link transmissions, and UL transmissions may also be referred to as reverse link transmissions.

[0057] The geographic coverage area 110 of the base station 105 may be divided into sectors that constitute a portion of the geographic coverage area 110, and each sector may be associated with a cellular cell. For example, each base station 105 may provide communication coverage for a macrocellular cell, a small cellular cell, a hotspot, or other types of cellular cells, or various combinations thereof. In some examples, the base station 105 may be mobile and therefore provide communication coverage for a mobile geographic coverage area 110. In some examples, different geographic coverage areas 110 associated with different technologies may overlap, and the overlapping geographic coverage areas 110 associated with different technologies may be supported by the same base station 105 or different base stations 105. The wireless communication system 100 may include, for example, a heterogeneous LTE / LTE-A / LTE-A Pro or NR network, in which different types of base stations 105 provide coverage for various geographic coverage areas 110.

[0058] The term "cell" refers to a logical communication entity for communicating with base station 105 (e.g., on a carrier), and may be associated with an identifier to distinguish adjacent cells operating via the same or different carriers (e.g., physical cell identifier (PCID), virtual cell identifier (VCID)). In some examples, a carrier may support multiple cells, and different cells may be configured according to different protocol types that may provide access to different types of devices (e.g., machine type communication (MTC), narrowband Internet of Things (NB-IoT), enhanced mobile broadband (eMBB), or others). In some cases, the term "cell" may refer to a portion of a geographic coverage area 110 (e.g., a sector) on which the logical entity operates.

[0059] Each UE 115 can be dispersed throughout the wireless communication system 100, and each UE 115 can be stationary or mobile. UE 115 can also be referred to as a mobile device, a wireless device, a remote device, a handheld device, or a subscriber device, or some other suitable term, wherein "device" can also be referred to as a unit, a station, a terminal, or a client. UE 115 can also be 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 can also refer to a wireless local loop (WLL) station, an Internet of Things (IoT) device, an Internet of Everything (IoE) device, or an MTC device, etc., which can be implemented in various items (such as electrical appliances, vehicles, meters, etc.).

[0060] 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 the information to a central server or application, which may utilize the information or present the information to a person interacting with the program or application. Some UEs 115 may be designed to collect information or implement automated behavior of machines. Examples of applications for MTC devices include: smart metering, inventory monitoring, water level monitoring, equipment monitoring, health care monitoring, field survival monitoring, weather and geographic event monitoring, queue management and tracking, remote security sensing, physical access control, and transaction-based commercial charging.

[0061] Some UEs 115 may be configured to employ a reduced power consumption mode of operation, such as half-duplex communication (e.g., a mode that supports unidirectional communication via transmission or reception but not simultaneous transmission and reception). In some examples, half-duplex communication may be performed with a reduced peak rate. Other power saving techniques for UE 115 include entering a power saving "deep sleep" mode when not engaged in active communications, or operating over a limited bandwidth (e.g., in accordance with narrowband communications). In some cases, UE 115 may be designed to support critical functions (e.g., mission critical functions), and the wireless communication system 100 may be configured to provide ultra-reliable communications for these functions.

[0062] In some cases, UE 115 may also be able to communicate directly with other UE 115 (e.g., using a peer-to-peer (P2P) or device-to-device (D2D) protocol). One or more UEs in a group of UEs 115 utilizing D2D communication may be within the geographic coverage area 110 of the base station 105. Other UEs 115 in this group may be outside the geographic coverage area 110 of the base station 105, or may not be able to receive transmissions from the base station 105 for other reasons. In some cases, each 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 cases, 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.

[0063] The base stations 105 may communicate with the core network 130 and with each other. For example, the base stations 105 may interface with the core network 130 via a backhaul link 132 (e.g., via S1, N2, N3, or other interfaces). 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) on a backhaul link 134 (e.g., via X2, Xn, or other interfaces).

[0064] The core network 130 may provide user authentication, access authorization, tracking, Internet Protocol (IP) connectivity, and other access, routing, or mobility functions. The core network 130 may be an evolved packet core (EPC), which may include at least one mobility management entity (MME), at least one serving gateway (S-GW), and at least one packet data network (PDN) gateway (P-GW). The MME may manage non-access layer (e.g., control plane) functions such as mobility, authentication, and bearer management of UEs 115 served by base stations 105 associated with the EPC. User IP packets may be delivered through the S-GW, which itself may be connected to the P-GW. The P-GW may provide IP address allocation and other functions. The P-GW may be connected to network operator IP services. Operator IP services may include access to the Internet, an intranet, an IP multimedia subsystem (IMS), or packet switched (PS) streaming services.

[0065] At least some network devices (such as base stations 105) may include subcomponents, such as access network entities, which may be examples of access node controllers (ANCs). Each access network entity may communicate with each UE 115 through a number of other access network transport entities, which may be referred to as radio heads, smart radio heads, or transmission / reception points (TRPs). In some configurations, the various functions of each access network entity or base station 105 may be distributed across various network devices (e.g., radio heads and access network controllers) or merged into a single network device (e.g., base station 105).

[0066] The wireless communication system 100 can operate using one or more frequency bands, typically in the range of 300 megahertz (MHz) to 300 gigahertz (GHz). In general, the 300 MHz to 3 GHz region is referred to as the ultra-high frequency (UHF) region or decimeter band because the wavelengths are in the range of from about 1 decimeter to 1 meter long. UHF waves can be blocked or redirected by buildings and environmental features. However, these waves can penetrate various structures sufficiently for macro cells to provide services to UEs 115 located indoors. Transmission of UHF waves can be associated with smaller antennas and shorter ranges (e.g., less than 100 km) compared to transmission using lower frequencies and longer waves in the high frequency (HF) or very high frequency (VHF) portion of the spectrum below 300 MHz.

[0067] The wireless communication system 100 may also operate in the Super High Frequency (SHF) region using frequency bands from 3 GHz to 30 GHz, also known as centimeter bands. The SHF region includes frequency bands that may be opportunistically used by devices that may be able to tolerate interference from other users, such as the 5 GHz Industrial, Scientific, and Medical (ISM) band.

[0068] The wireless communication system 100 may also operate in the extremely high frequency (EHF) division of the spectrum (e.g., from 30 GHz to 300 GHz), which is also referred to 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 antenna of the corresponding device may be even smaller and more closely spaced than the UHF antenna. In some cases, this may facilitate the use of antenna arrays within the UE 115. However, the propagation of EHF transmissions may be subject to even greater atmospheric attenuation and shorter range than SHF or UHF transmissions. The technology disclosed herein may be adopted across transmissions using one or more different frequency divisions, and the use of frequency bands specified across these frequency divisions may differ by country or regulatory agency.

[0069] In some cases, the wireless communication system 100 may utilize both licensed and unlicensed radio frequency spectrum bands. For example, the wireless communication system 100 may employ license assisted access (LAA), LTE unlicensed (LTE-U) radio access technology, or NR technology in an unlicensed band (such as a 5 GHz ISM band). When operating in an unlicensed radio frequency spectrum band, wireless devices (such as base stations 105 and UE 115) may employ a listen-before-talk (LBT) procedure to ensure that the frequency channel is clear before transmitting data. In some cases, operations in unlicensed bands may be based on carrier aggregation configuration (e.g., LAA) in coordination with component carriers operating in licensed bands. Operations in unlicensed spectrum may include DL transmissions, UL transmissions, peer-to-peer transmissions, or a combination of these. Duplexing in unlicensed spectrum may be based on frequency division duplexing (FDD), time division duplexing (TDD), or a combination of the two.

[0070] In some examples, the base station 105 or the UE 115 may be equipped with multiple antennas, which may be used to employ techniques such as transmit diversity, receive diversity, multiple-input multiple-output (MIMO) communication, or beamforming. For example, the wireless communication system 100 may use a transmission scheme between a transmitting device (e.g., the base station 105) and a receiving device (e.g., the UE 115), wherein the transmitting device is equipped with multiple antennas and the receiving device is equipped with one or more antennas. MIMO communication may employ multipath signal propagation to increase spectral efficiency by transmitting or receiving multiple signals via different spatial layers, which may be referred to as spatial multiplexing. For example, the transmitting device may transmit multiple signals via different antennas or different antenna combinations. Similarly, the receiving device may receive multiple signals via different antennas or different antenna combinations. Each of these 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. Different spatial layers may be associated with different antenna ports for channel measurement and reporting. MIMO technology includes single-user MIMO (SU-MIMO), in which multiple spatial layers are transmitted to the same receiving device, and multi-user MIMO (MU-MIMO), in which multiple spatial layers are transmitted to multiple devices.

[0071] 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 or a receive beam) along a spatial path between the transmitting device and the receiving device. Beamforming may be achieved by combining signals communicated via antenna elements of an antenna array so that signals propagating at a particular orientation relative to the antenna array experience constructive interference, while other signals experience destructive interference. Adjustments to signals communicated via antenna elements may include the transmitting device or the receiving device applying a particular amplitude and phase shift to the signal carried via each antenna element associated with the device. Adjustments associated with each antenna element may be defined by a set of beamforming weights associated with a particular orientation (e.g., relative to the antenna array of the transmitting device or the receiving device, or relative to some other orientation).

[0072] In one example, the base station 105 may use multiple antennas or antenna arrays to perform beamforming operations for directional communication with the UE 115. For example, some signals (e.g., synchronization signals, reference signals, beam selection signals, or other control signals) may be transmitted multiple times by the base station 105 in different directions, which may include a signal being transmitted according to different beamforming weight sets associated with different transmission directions. The transmissions in different beam directions may be used (e.g., by the base station 105 or a receiving device, such as the UE 115) to identify the beam direction used by the base station 105 for subsequent transmission and / or reception.

[0073] Some signals, such as data signals associated with a particular recipient device, may be transmitted by base station 105 in a single beam direction (e.g., a direction associated with a recipient device, such as UE 115). In some examples, a beam direction associated with transmissions along a single beam direction may be determined based at least in part on signals transmitted in different beam directions. For example, UE 115 may receive one or more signals transmitted by base station 105 in different directions, and UE 115 may report to base station 105 an indication of the signals received by it with the highest signal quality or other acceptable signal quality. Although these techniques are described with reference to signals transmitted by base station 105 in one or more directions, UE 115 may use similar techniques for transmitting signals multiple times in different directions (e.g., for identifying a beam direction used by UE 115 for subsequent transmission or reception) or for transmitting signals in a single direction (e.g., for transmitting data to a recipient device).

[0074] A receiving device (e.g., UE 115, which may be an example of a mmW receiving device) may try multiple receive beams when receiving various signals (such as synchronization signals, reference signals, beam selection signals, or other control signals) from base station 105. For example, the receiving device may try multiple receive directions by receiving via different antenna subarrays, processing received signals according to different antenna subarrays, receiving according to different receive beamforming weight sets applied to signals received at multiple antenna elements of an antenna array, or processing received signals according to different receive 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 receive beams or receive directions. In some examples, the receiving device may use a single receive beam to receive along a single beam direction (e.g., when receiving a data signal). The single receive beam may be aligned on a beam direction determined at least in part based on listening according to different receive beam directions (e.g., a beam direction determined to have the highest signal strength, highest signal-to-noise ratio, or other acceptable signal quality based at least in part on listening according to multiple beam directions).

[0075] In some cases, the antennas of a base station 105 or a UE 115 may be located within one or more antenna arrays that may support MIMO operations or transmit or receive beamforming. For example, one or more base station antennas or antenna arrays may be co-located at an antenna assembly, such as an antenna tower. In some cases, the antennas or antenna arrays associated with a base station 105 may be located at different geographic locations. A base station 105 may have an antenna array having several rows and columns of antenna ports that the base station 105 may use to support beamforming for communications with a UE 115. Likewise, a UE 115 may have one or more antenna arrays that may support various MIMO or beamforming operations.

[0076] In some cases, the wireless communication system 100 can be a packet-based network that operates according to a layered protocol stack. In the user plane, the communication of the bearer or packet data convergence protocol (PDCP) layer can be based on IP. The radio link control (RLC) layer can perform packet segmentation and reassembly to communicate on the logical channel. The media access control (MAC) layer can perform priority handling and multiplex logical channels into transport channels. The MAC layer can also use HARQ to provide retransmission of the MAC layer, thereby improving link efficiency. In the control plane, the radio resource control (RRC) protocol layer can provide the establishment, configuration and maintenance of the RRC connection of the radio bearer that supports user plane data between the UE 115 and the base station 105 or the core network 130. At the physical layer, the transport channel can be mapped to the physical channel.

[0077] In some cases, UE 115 and base station 105 may support retransmission of data to increase the likelihood that the data is successfully received. HARQ feedback is a technique that increases the likelihood of correctly receiving data on communication link 125. HARQ may 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 in poor radio conditions (e.g., signal-to-noise ratio conditions). In some cases, a wireless device may support simultaneous slot HARQ feedback, where the device may provide HARQ feedback in a specific time slot for data received in a previous symbol in the time slot. In other cases, the device may provide HARQ feedback in a subsequent time slot or according to some other time interval.

[0078] The time interval in LTE or NR can be represented by a basic time unit (which may refer to a sampling period T, for example). s =1 / 30,720,000 seconds). The time intervals of the communication resources may be organized according to radio frames each having a duration of 10 milliseconds (ms), where the frame period may be expressed as T f =307,200T s. A radio frame may be identified by a system frame number ranging from 0 to 1023. Each frame may include 10 subframes numbered from 0 to 9, and each subframe may have a duration of 1 ms. A subframe may be further divided into 2 time slots, each time slot having a duration of 0.5 ms, and each time slot may contain 6 or 7 modulation code element periods (e.g., depending on the length of a cyclic prefix prepended to each code element period). Excluding the cyclic prefix, each code element period may contain 2048 sampling periods. In some cases, a subframe may be the minimum scheduling unit of the wireless communication system 100 and may be referred to as a transmission time interval (TTI). In other cases, the minimum scheduling unit of the wireless communication system 100 may be shorter than a subframe or may be dynamically selected (e.g., in a burst of a shortened TTI (sTTI) or in a selected component carrier using sTTI).

[0079] In some wireless communication systems, a time slot may be further divided into a plurality of mini-slots containing one or more symbols. In some instances, a symbol of a mini-slot or a mini-slot may be the minimum scheduling unit. For example, each symbol may vary in duration depending on the subcarrier spacing or the operating frequency band. Further, some wireless communication systems may implement time slot aggregation, wherein a plurality of time slots or mini-slots are aggregated together and used for communication between UE 115 and base station 105.

[0080] The term "carrier" refers to a set of radio frequency spectrum resources having a defined physical layer structure for supporting communications on the communication link 125. For example, a carrier of the communication link 125 may include a portion of a radio frequency spectrum band that operates according to a physical layer channel for a given radio access technology. Each physical layer channel may carry user data, control information, or other signaling. A carrier may be associated with a predefined frequency channel (e.g., an Evolved Universal Mobile Telecommunications System Terrestrial Radio Access (E-UTRA) Absolute Radio Frequency Channel Number (EARFCN)) and may be located according to a channel grid for discovery by a UE 115. A carrier may be DL or UL (e.g., in FDD mode), or configured to carry DL communications and UL communications (e.g., in TDD mode). In some examples, a signal waveform transmitted on a carrier may include multiple subcarriers (e.g., using a multi-carrier modulation (MCM) technique such as orthogonal frequency division multiplexing (OFDM) or discrete Fourier transform spread OFDM (DFT-S-OFDM)).

[0081] For different radio access technologies (e.g., LTE, LTE-A, LTE-A Pro, NR), the organizational structure of the carrier can be different. For example, the communication on the carrier can be organized according to TTIs or time slots, each of which can include user data and control information or signaling to support decoding of the user data. The carrier can also include dedicated acquisition signaling (e.g., synchronization signals or system information, etc.) and control signaling to coordinate the operation of the carrier. In some examples (e.g., in a carrier aggregation configuration), the carrier may also have acquisition signaling or control signaling to coordinate the operation of other carriers.

[0082] Physical channels may be multiplexed on a carrier according to various techniques. Physical control channels and physical data channels may be multiplexed on a DL carrier, for example, using TDM techniques, frequency division multiplexing (FDM) techniques, or hybrid TDM-FDM techniques. In some examples, control information transmitted in a physical control channel may be distributed in a cascaded manner between different control regions (e.g., between a common control region or a common search space and one or more UE-specific control regions or UE-specific search spaces).

[0083] A carrier may be associated with a particular bandwidth of the radio frequency spectrum, and in some examples, the carrier bandwidth may be referred to as the "system bandwidth" of the carrier or wireless communication system 100. For example, the carrier bandwidth may be one of several predetermined bandwidths of a carrier for a particular radio access technology (e.g., 1.4, 3, 5, 10, 15, 20, 40, or 80 MHz). In some examples, each served UE 115 may be configured to operate on part or all of the carrier bandwidth. In other examples, some UEs 115 may be configured to operate using a narrowband protocol type associated with a predefined portion or range (e.g., a set of subcarriers or RBs) within a carrier (e.g., an "in-band" deployment of a narrowband protocol type).

[0084] In a system using MCM technology, 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). Thus, the more resource elements received by UE 115 and the higher the order of the modulation scheme, the higher the data rate of UE 115 can be. In a MIMO system, wireless communication resources may refer to a combination of radio frequency spectrum resources, time resources, and space resources (e.g., space layers), and the use of multiple space layers may further increase the data rate of communication with UE 115.

[0085] A device (e.g., base station 105 or UE 115) of wireless communication system 100 may have a hardware configuration that supports communication on a particular carrier bandwidth, or may be configurable to support communication on one of a set of carrier bandwidths. In some examples, wireless communication system 100 may include base stations 105 and / or UEs 115 that support simultaneous communication via carriers associated with more than one different carrier bandwidths.

[0086] The wireless communication system 100 may support communication with the UE 115 on multiple cells or carriers, a feature that may be referred to as carrier aggregation or multi-carrier operation. The UE 115 may be configured with multiple DL component carriers and one or more UL component carriers according to a carrier aggregation configuration. Carrier aggregation may be used with both FDD and TDD component carriers.

[0087] In some cases, the wireless communication system 100 may utilize an enhanced component carrier (eCC). An eCC may be characterized by one or more features including a wider carrier or frequency channel bandwidth, a shorter symbol duration, a shorter TTI duration, or a modified control channel configuration. In some cases, an eCC may be associated with a carrier aggregation configuration or a dual connectivity configuration (e.g., when multiple serving cells have suboptimal or non-ideal backhaul links). An eCC may also be configured for use in an unlicensed spectrum or a shared spectrum (e.g., where more than one operator is allowed to use the spectrum). An eCC characterized by a wide carrier bandwidth may include one or more segments that may be utilized by a UE 115 that is not capable of monitoring the entire carrier bandwidth or is otherwise configured to use a limited carrier bandwidth (e.g., to save power).

[0088] In some cases, an eCC may utilize a different symbol duration than other component carriers, which may include using a reduced symbol duration compared to the symbol duration of other component carriers. A shorter symbol duration may be associated with an increased spacing between adjacent subcarriers. A device utilizing an eCC (such as a UE 115 or a base station 105) may transmit a wideband signal (e.g., according to a frequency channel or carrier bandwidth of 20, 40, 60, 80 MHz, etc.) with a reduced symbol duration (e.g., 16.67 microseconds). A TTI in an eCC may include one or more symbol periods. In some cases, the TTI duration (i.e., the number of symbol periods in a TTI) may be variable.

[0089] The wireless communication system 100 may be an NR system that may utilize any combination of licensed, shared, and unlicensed spectrum bands, etc. The flexibility of eCC symbol duration and subcarrier spacing may allow eCC to be used across multiple spectrums. In some examples, NR shared spectrum may improve spectrum utilization and spectrum efficiency, particularly through dynamic vertical (e.g., across frequency domain) and horizontal (e.g., across time domain) sharing of resources.

[0090] The base station 105 may transmit system information to the UE 115 via a broadcast channel. For example, in an NR system, a master information block (MIB) may be delivered via a physical broadcast channel (PBCH), a system information block (SIB) (such as SIB1) may be delivered via a DL shared channel (DL-SCH) as configured by a remaining minimum system information (RMSI) parameter, and other SIBs may be delivered via a DL-SCH as configured by an other system information (OSI) parameter. The broadcast system information may be common to all UEs 115 in the coverage area 110. Because the broadcast system information is sent to multiple UEs 115 distributed across the coverage area 110, the base station 105 may transmit the broadcast channel to a larger area with high reliability.

[0091] The base station 105 may transmit information to the UE 115 based on a dynamic scheduling method, such as a DL grant in the PDCCH that schedules a DL transmission in the PDSCH. For scheduled transmissions, the network may support feedback via a HARQ feedback process. In the HARQ process, the UE 115 may transmit an acknowledgment (ACK) message to indicate that the UE 115 successfully received the transmission, or the UE 115 may transmit a NACK message to indicate that the UE 115 did not successfully receive the transmission. In some examples, the UE 115 may transmit an ACK message or a NACK message in a HARQ feedback resource, such as in a physical uplink control channel (PUCCH). The base station 105 may retransmit the DL grant and the DL transmission upon receiving the NACK message.

[0092] In some examples, the base station 105 may transmit the broadcast system information to multiple UEs 115 based on a dynamic scheduling method. However, the base station 105 may not support HARQ feedback for the broadcast system information. The UE 115 may not indicate to the network whether the UE 115 successfully received and decoded the broadcast system information, and / or the base station 105 may not support retransmission of the broadcast system information based on the UE 115 transmitting NACK feedback. However, the UE 115 can still receive multiple transmissions of the broadcast system information, which the UE 115 can use to retry failed decoding or combine before decoding to improve decoding reliability.

[0093] The base station 105 may also transmit multicast information other than system information to a group of UEs 115. Similar to the case of broadcasting system information, supporting or responding to feedback (e.g., HARQ feedback) from UEs 115 that receive the multicast information may be challenging for the base station 105. For example, multiple UEs 115 in the group may attempt to transmit HARQ feedback in an ACK message or a NACK message at the same time. This simultaneous HARQ feedback transmission may result in a conflict or congestion of UL resources and an increase in system overhead for the base station and the network. In addition, the base station 105 may transmit multicast information at a single time (i.e., without repetition), and therefore the group of UEs 115 may not be able to combine repeated transmissions to improve decoding reliability.

[0094] Provided herein are techniques for supporting feedback for multicast communications. A UE 115 in a group of UEs 115 may receive multicast information from a base station 105 in a DL transmission scheduled by a DL grant. In some examples, the base station 105 may transmit the multicast information in a beam sweeping procedure. The UE 115 may attempt to decode a message containing the multicast information in the DL transmission. If the UE 115 determines that the message is successfully decoded, the UE 115 may determine not to send feedback to the base station. If the UE 115 determines that the message is not successfully decoded, the UE 115 may send NACK feedback to the base station 105 to indicate that the message is not successfully decoded.

[0095] The DL grant may also indicate a UL resource set for the group of UEs 115 to use to transmit NACK feedback. The UL resource set may include time and frequency resources in which the group of UEs 115 may transmit NACK feedback to the base station. Each UE 115 in the group of UEs 115 may be directed to use a specific UL resource in the UL resource set, and the UL resources for each UE 115 may at least partially overlap. In some examples, the UE 115 may transmit NACK feedback via a UL transmit beam in the UL resource.

[0096] After transmitting the DL grant and the DL transmission, the base station 105 may monitor the indicated UL resource set for NACK feedback. If the base station 105 receives NACK feedback from at least one UE 115 in the group of UEs 115 in the indicated UL resource set, the base station 105 may determine to retransmit the multicast information to the group of UEs 115 in a subsequent DL transmission scheduled by the DL grant. In some examples, the base station 105 may determine to retransmit the multicast information in the DL resources via DL transmit beams corresponding to those UL resources in which the NACK feedback was received.

[0097] Figure 2An example of a wireless communication system 200 that supports feedback for multicast communications according to aspects of the present disclosure is illustrated. In some examples, the wireless communication system 200 can implement aspects of the wireless communication system 100. The wireless communication system 200 can include a base station 205 and a UE 215, which can be referenced Figure 1 An example of a base station 105 and a UE 115 is depicted. Base station 205 may provide network coverage for a geographic coverage area 210. Base station 205 may transmit DL transmissions to UE 215 via communication link 225.

[0098] The base station 205 may transmit the multicast information in a DL transmission scheduled by the DL grant to the UE 215. The base station may additionally indicate in the DL grant the UL resources for the UE 215 to use to transmit the NACK feedback.

[0099] Each UE 215 in the group of UEs 215 may attempt to decode the message containing the multicast information in the DL transmission. For example, UE 215-a and UE 215-b may each determine that the message is successfully decoded, and UE 215-a and UE 215-b may determine not to transmit NACK feedback to base station 205. In some examples, UE 215-c may determine that the message is not successfully decoded. UE 215-c may transmit NACK feedback to base station 205 in the UL resources indicated in the DL grant to indicate that the message is not successfully decoded. In some examples, UE 215-c may transmit the NACK feedback in a HARQ NACK message, a special bit sequence, a message preamble, or a combination thereof.

[0100] The base station 205 may receive NACK feedback from the UE 215-c and determine that the base station 205 received NACK feedback from at least one UE 215 in the group of UEs 215. In some examples, the base station 205 may not identify how many or which UEs 215 in the group of UEs 215 transmitted the NACK feedback. The base station 205 may determine to retransmit the multicast information to the group of UEs 315 in a subsequent DL transmission scheduled by the DL grant based on determining that the NACK feedback was received.

[0101] Figure 3 An example of a wireless communication system 300 that supports feedback for multicast communications according to aspects of the present disclosure is illustrated. In some examples, the wireless communication system 300 can implement aspects of the wireless communication system 100. The wireless communication system 300 can include a base station 305 and a UE 315, which can be referenced Figure 1 Depicted examples of base stations 105 and UEs 115. Base station 305 may provide network coverage for geographic coverage area 310. Base station 305 may transmit DL transmissions to UE 315 via DL transmit beam 320 in a beam sweeping procedure.

[0102] Base station 305 may transmit multicast information via DL transmit beam 320 in a DL transmission scheduled by a DL grant. Figure 3 In the example illustrated in , DL transmit beam 320-a is associated with UE 315-a, UE 315-b, and UE 315-c. In addition, DL transmit beam 320-b is associated with UE 315-c and UE 315-d. Each DL transmit beam 320 may be associated with an additional UE 315 (not shown). One or more DL grants may schedule one or more DL transmissions via each DL transmit beam 320. Each DL grant may additionally indicate a set of UL resources for UE 315 to transmit NACK feedback.

[0103] Each UE 315 in the group of UEs 315 may attempt to decode the message containing the multicast information in the DL transmission. In one example, UEs 315-a, 315-b, and 315-c may determine that the message is successfully decoded, and may determine not to transmit NACK feedback to the base station 305. UE 315-d may determine that the message is not successfully decoded. UE 315-d may transmit NACK feedback to the base station 305 in the UL resources indicated in the DL grant associated with the DL transmit beam 320-b to indicate that the message is not successfully decoded. The base station 305 may receive NACK feedback from UE 315-d. The base station 305 may determine that the base station 305 receives NACK feedback from at least one UE 315 associated with the DL transmit beam 320-b in the group of UEs 315 based on the UL resources in which the base station 305 receives the NACK feedback. The base station 305 may determine to retransmit the multicast information via the DL transmit beam 320-b in a subsequent DL transmission scheduled by the DL grant.

[0104] The beam sweeping procedure may allow UE 315-c to receive repetitions of multicast information via DL transmit beams. Each DL transmit beam may be associated with a UE group, and the UE may belong to multiple UE groups. UE 315-c may receive DL transmissions via multiple DL transmit beams 320-a and 320-b. UE 315-c may combine DL transmissions before attempting to decode the message to improve decoding reliability. In one example, UE 315-a, 315-b, and 315-d may determine that the message is successfully decoded, and may determine not to transmit NACK feedback to base station 305. UE 315-c may determine that the message is not successfully decoded even after combining the DL transmissions. UE 315-c may transmit NACK feedback in UL resources associated with one or more of DL transmit beams 320-a and 320-b. In some examples, UE 315-c may transmit NACK feedback in UL resources associated with both DL transmit beam 320-a and DL transmit beam 320-b. Base station 305 may determine to retransmit multicast information via both DL transmit beam 320-a and DL transmit beam 320-b based on receiving NACK feedback in the UL resources. In other examples, UE 315-c may measure the link quality of the UL transmit beam associated with the UL resources. UE 315-c may transmit NACK feedback in the UL resources associated with DL transmit beam 320-a based on determining the link quality. Base station 305 may determine to retransmit multicast information via DL transmit beam 320-a based on receiving NACK feedback in the associated UL resources.

[0105] Figure 4 An example of a transmission timeline 400 supporting feedback for multicast communications according to aspects of the present disclosure is illustrated. In some examples, the transmission timeline 400 can implement aspects of the wireless communication systems 100 and 200. The transmission timeline 400 can be associated with one or more base stations 405, which can be referenced to Figure 1 An example of a base station 105 is described.

[0106] The base station 405-a may transmit multicast information to the first UE group in the time slot 410-a. In some examples, the time slot 410-a may be referred to as the time slot n, where n is the time slot index. The base station 405-a may transmit a DL grant in the PDCCH 415-a. The PDCCH 415-a may schedule DL transmissions in the PDSCH 420-a and may indicate the UL resources 425-a for NACK feedback in the time slot 410-b. In some examples, the base station 405-a may indicate the UL resources 425-a to the first UE group in the PUCCH resource indicator in the PDCCH 415-a. In some examples, the time slot 410-b may be referred to as the time slot n+k1, where k1 is the number of time slots between the time slot containing the multicast information (e.g., the time slot 410-a) and the time slot containing the UL resources 425-a indicated for NACK feedback (e.g., the time slot 410-b). In some examples, base station 405-a may indicate number k1 to the first UE group in a PDSCH to HARQ feedback timing indicator in PDCCH 415-a. Base station 405-a may not receive NACK feedback in UL resource 425-a and may determine not to retransmit multicast information in time slot 410-c. In some examples, time slot 410-c may be referred to as time slot n+k1+k3, where k3 is the number of time slots between the time slot containing UL resource 425-a indicated for NACK feedback (e.g., time slot 410-b) and the time slot that can be used to retransmit multicast information (e.g., time slot 410-c).

[0107] The base station 405-b may transmit multicast information to the second UE group in time slot 410-d. In some examples, time slot 410-d may be referred to as time slot n. The base station 405-b may transmit a DL grant in a PDCCH 415-b. The PDCCH 415-b may schedule DL transmissions in a PDSCH 420-b and may indicate UL resources 425-b for NACK feedback in time slot 410-e. In some examples, the base station 405-b may indicate UL resources 425-b to the second UE group in a PUCCH resource indicator in the PDCCH 415-b. In some examples, time slot 410-e may be referred to as time slot n+k1. In some examples, the base station 405-b may indicate the number k1 to the second UE group in a PDSCH to HARQ feedback timing indicator in the PDCCH 415-b. The base station 405-b may receive NACK feedback in UL resources 425-b. In some examples, the base station 405-b may receive the NACK feedback in a HARQ NACK message, a special bit sequence, a message preamble, or a combination thereof. The base station 405-b may determine to retransmit the multicast information in the time slot 410-f based on receiving the NACK feedback in the UL resource 425-b. In some examples, the time slot 410-f may be referred to as the time slot n+k1+k3. The base station 405-b may transmit a second DL grant in the PDCCH 415-c. The PDCCH 415-c may schedule a second DL transmission in the PDSCH 420-c and may indicate the UL resource 425-c for the NACK feedback in the time slot 410-g. In some examples, the time slot 410-g may be referred to as the time slot n+2k1+k3. The base station 405-b may not receive the NACK feedback in the UL resource 425-c and may determine not to retransmit the multicast information in the subsequent time slot 410 (not shown).

[0108] Figure 5 An example of a transmission timeline 500 that supports feedback for multicast communications in accordance with aspects of the present disclosure is illustrated. In some examples, the transmission timeline 500 can implement aspects of the wireless communication systems 100 and 300. The transmission timeline 500 can be associated with a base station 505, which can be a reference Figure 1 An example of a base station 105 is described.

[0109] Base station 505 may transmit multicast information to a first UE group in time slot 510-a and to a second UE group in time slot 510-b. The first UE group may be associated with a first DL transmit beam and the second UE group may be associated with a second DL transmit beam. In some examples, one or more UEs may belong to the first UE group and the second UE group. In some examples, time slot 510-a may be referred to as time slot n and time slot 510-b may be referred to as time slot n+1.

[0110] The base station 505 may transmit a first DL grant via a first DL transmit beam in a PDCCH 515-a and a second DL grant via a second DL transmit beam in a PDCCH 515-b. The PDCCH 515-a may schedule a first DL transmission in a PDSCH 520-a and may indicate UL resources 525-a for NACK feedback in a time slot 510-c. The PDCCH 515-b may schedule a second DL transmission in a PDSCH 520-b and may indicate UL resources 525-b for NACK feedback in a time slot 510-d. In some examples, the base station 505 may indicate the UL resources 525-b to a first UE group in a PUCCH resource indicator in a PDCCH 515-a and indicate the UL resources 525-b to a second UE group in a PUCCH resource indicator in a PDCCH 515-b. In some examples, time slot 510-c may be referred to as time slot n+k1 and time slot 510-d may be referred to as time slot n+k1+1. In some examples, base station 505 may indicate number k1 in a PDSCH to HARQ feedback timing indicator in PDCCH 515-a to a first group of UEs and may indicate number k1 in a PDSCH to HARQ feedback timing indicator in PDCCH 515-b to a second group of UEs.

[0111] The base station 505 may receive NACK feedback in UL resource 525-b, but not in UL resource 525-a. In some examples, the base station 505 may receive the NACK feedback in a HARQ NACK message, a special bit sequence, a message preamble, or a combination thereof. The base station 505 may determine not to retransmit the multicast information via the first DL transmit beam in the time slot 510-e based on the base station 505 not receiving NACK feedback in the UL resource 525-a. The base station 505 may additionally determine to retransmit the multicast information via the second DL transmit beam in the time slot 510-f based on receiving NACK feedback in the UL resource 525-b. In some examples, the time slot 510-e may be referred to as the time slot n+k1+k3 and the time slot 510-f may be referred to as the time slot n+k1+k3+1. The base station 505 may transmit a third DL grant via the second DL transmit beam in the PDCCH 515-c. The PDCCH 515 - c may schedule a third DL transmission in the PDSCH 520 - c and may indicate UL resources for NACK feedback in a subsequent slot (not shown).

[0112] Figure 6An example of a process flow 600 for supporting feedback for multicast communications according to aspects of the present disclosure is illustrated. In some examples, the process flow 600 can implement aspects of wireless communication systems 100, 200, and 300. The process flow 600 may include a base station 605, a UE 615-a, and a UE 615-b, which may be referenced Figures 1 to 5 Examples of corresponding devices described. Base station 605, UE 615-a and UE 615-b may implement one or more techniques for acknowledging feedback as discussed herein. The following alternative examples may be implemented, in which some steps are performed in a different order than described or not performed at all. In some cases, each step may include additional features not mentioned below, or further steps may be added.

[0113] At 620, the base station 605 may, in some examples, determine a set of DL transmit beams as part of a beam sweeping procedure. The base station 605 may configure at least a first DL transmit beam for transmitting DL resources to the UE 615-a and the UE 615-b. In some examples, the base station 605 may additionally configure additional DL transmit beams for transmitting DL resources to one or both of the UE 615-a and the UE 615-b.

[0114] At 625, the base station 605 may determine DL and UL resources for multicast communication with the UE 615. The base station 605 may determine a set of DL resources for DL ​​transmissions including multicast information to the UE 615. In some examples, the DL resources may include a PUSCH. The base station 605 may additionally determine a set of UL resources for NACK feedback information corresponding to the DL transmission. In some examples, the UL resource set may be included in a PUCCH, a PUSCH, a RACH, or other resources within or outside the system bandwidth, or a combination thereof. In some examples, the base station 605 may additionally determine additional DL resources for transmissions via additional DL transmit beams and corresponding UL resources for the additional DL transmissions in the additional DL resources.

[0115] At 630, the base station may transmit a DL grant to the UE 615. The DL grant may indicate to the UE 615 a set of DL resources for DL ​​transmissions including multicast information. The DL grant may additionally indicate a set of UL resources for the UE 615 to use for NACK feedback corresponding to the DL transmission. Each UE 615 in the group of UEs 615 may be directed to use UL resources in the UL resource set, and the UL resources for each UE 615 may at least partially overlap.

[0116] In some examples, base station 605 may transmit a DL grant via a first DL transmit beam configured for UE 615-a and UE 615-b. In some examples, base station 605 may transmit additional DL grants via additional DL transmit beams. Each additional DL grant may indicate a corresponding DL resource set for additional DL transmission and a corresponding UL resource set for NACK feedback.

[0117] At 635, UE 615 may each identify a UL resource set for transmitting NACK feedback based on the indication in the DL grant. In some examples, UE 615 may additionally identify a corresponding UL resource set indicated in each additional DL grant received via an additional DL transmit beam. In some examples, UE 615 may identify a UL transmit beam for transmitting NACK feedback to base station 605.

[0118] UE 615 may additionally monitor the DL resource sets indicated in the DL grant for DL ​​transmissions including multicast information. In some examples, UE 615 may additionally monitor the corresponding DL resource sets for additional DL transmissions indicated in each additional DL grant.

[0119] At 645, each UE 615 may attempt to decode a message containing multicast information in the DL transmission. In some examples, UE 615-a may determine whether the message is successfully decoded based on whether the CRC of the message passes or fails, wherein UE 615-a may detect errors in decoding the message based on calculating a number of checksum bits following the message. If UE 615-a determines that the message is successfully decoded (e.g., CRC passes), the UE 615-a may determine not to send feedback to the base station. If UE 615-a determines that the message is not successfully decoded (e.g., CRC fails), the UE 615-a may determine to send NACK feedback to base station 605 to indicate that the message is not successfully decoded.

[0120] In some examples, the beam sweeping procedure may allow the UE 615-a to receive repetitions of multicast information from the base station 605 via multiple DL transmit beams. The UE 615-a may combine DL transmissions before attempting to decode the message to improve decoding reliability. If the UE 615-a does not successfully decode the message even after combining, the UE 615-a may determine to transmit NACK feedback in the UL resources indicated by one or more DL grants.

[0121] At 650, base station 605 may monitor the determined set of UL resources for NACK feedback information corresponding to the DL transmission. In some examples, base station 605 may additionally monitor UL resources corresponding to additional DL transmissions transmitted via additional DL transmit beams.

[0122] At 655, UE 615-a may transmit NACK feedback to base station 605. In some examples, UE 615-a may transmit NACK feedback based on SFN configuration. In some examples, UE 615-a may transmit the NACK feedback in a HARQ NACK message, a special bit sequence, a message preamble, or a combination thereof. The group of UEs 615 may transmit NACK feedback using a common waveform, a common sequence, a common resource mapping, or a combination thereof. In some examples, such as when UE 615-a receives multiple DL grants via multiple DL transmit beams, UE 615-a may transmit NACK feedback in the UL resources indicated by one or more of these DL grants. In some examples, UE 615-a may transmit NACK feedback in the UL resources indicated by multiple DL grants received via multiple DL transmit beams. In other examples, UE 615-a may transmit NACK feedback in the UL resource set indicated by the DL grant transmitted via the first DL transmit beam. The base station may determine to transmit NACK feedback in the UL resource set based on measuring the link quality of the UL transmit beam set.

[0123] The base station may determine that NACK feedback is received from at least one UE 615 in the group of UEs 615, and may not identify how many or which UEs 615 in the group of UEs 615 transmitted the NACK feedback. In some examples, the base station 605 may also receive NACK feedback from the UE 615-b based on whether the UE 615-b successfully decoded the message in the DL transmission. Based on receiving the NACK feedback, the base station 605 may determine to retransmit the multicast information to the group of UEs 615 in a subsequent DL transmission scheduled by the DL grant. In some examples, the base station 605 may determine to retransmit the multicast information in the DL resources via a DL transmit beam corresponding to the UL resources in which the NACK feedback was received.

[0124] Figure 7 A block diagram 700 of a device 705 supporting feedback for multicast communications according to aspects of the present disclosure is shown. The device 705 may be an example of aspects of a UE 115 as described herein. The device 705 may include a receiver 710, a communication manager 715, and a transmitter 720. The device 705 may also include a processor. Each of these components may be in communication with each other (e.g., via one or more buses).

[0125] 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 feedback for multicast communications, etc.). The information may be passed to other components of the device 705. The receiver 710 may be a reference Fig.10 Examples of aspects of the described transceiver 1020. The receiver 710 may utilize a single antenna or a collection of antennas.

[0126] The communication manager 715 may receive a DL grant from a base station, the DL grant indicating a DL resource set for DL ​​transmission to a set of UEs including the UE; identify a UL resource set for negative acknowledgement feedback information corresponding to the DL transmission based on the DL grant; monitor the DL resource set to find a DL transmission from the base station; and transmit a feedback message to the base station via the UL resource set based on the monitoring, wherein the feedback message indicates that the reception of the DL transmission was unsuccessful. The actions performed by the communication manager 715 as described herein may be implemented to achieve one or more potential advantages. An implementation may allow the UE 115 to save power and increase battery life by communicating with the base station 105 more efficiently. For example, the UE 115 may more efficiently obtain information transmitted by the base station 105 in a multicast message because the UE 115 may be able to combine multiple multicast transmissions (e.g., in a multi-beam transmission scenario) or may be able to provide feedback if a multicast transmission is not successfully received at the UE 115. In such a situation, UE 115 may improve the likelihood of a successful decoding procedure for the multicast information by combining multiple multicast transmissions or one or more retransmissions of the multicast information (e.g., in response to UE 115 providing NACK feedback). Another implementation may provide improved quality of service and reliability at UE 115 because latency and the number of separate resources allocated to a group of UEs including UE 115 may be reduced. Communication manager 715 may be an example of aspects of communication manager 1010 described herein.

[0127] The communication manager 715 or its subcomponents may be implemented in hardware, in 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 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.

[0128] The communication manager 715 or its subcomponents may be physically located at various locations, including being distributed such that portions of the functionality are implemented by one or more physical components at different physical locations. In some examples, according to various aspects of the present disclosure, the communication manager 715 or its subcomponents may be separate and distinct components. In some examples, according to various aspects of the present disclosure, the communication manager 715 or its subcomponents may be combined with one or more other hardware components (including, but not limited to, input / output (I / O) components, a transceiver, a network server, another computing device, one or more other components described in the present disclosure, or a combination thereof).

[0129] The transmitter 720 may transmit signals generated by other components of the device 705. In some examples, the transmitter 720 may be co-located with the receiver 710 in a transceiver module. For example, the transmitter 720 may be a reference Fig.10 Examples of aspects of the described transceiver 1020. The transmitter 720 may utilize a single antenna or a collection of antennas.

[0130] In some examples, the communication manager 715 may be implemented as an integrated circuit or chipset for a mobile device modem, and the receiver 705 and transmitter 720 may be implemented as analog components (e.g., amplifiers, filters, antennas, etc.) coupled to the mobile device modem to enable wireless transmission and reception on one or more frequency bands.

[0131] Figure 8 A block diagram 800 of a device 805 supporting feedback for multicast communications according to aspects of the present disclosure is shown. The device 805 may be an example of aspects of the device 705 or UE 115 as described herein. The device 805 may include a receiver 810, a communication manager 815, and a transmitter 840. The device 805 may also include a processor. Each of these components may be in communication with each other (e.g., via one or more buses).

[0132] 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 feedback for multicast communications, etc.). The information may be passed to other components of the device 805. The receiver 810 may be a reference Fig.10 Examples of aspects of the described transceiver 1020. The receiver 810 may utilize a single antenna or a collection of antennas.

[0133] The communication manager 815 may be an example of aspects of the communication manager 715 as described herein. The communication manager 815 may include a grant receiver 820, an uplink resource identifier 825, a monitoring component 830, and a feedback manager 835. The communication manager 815 may be an example of aspects of the communication manager 1010 described herein.

[0134] The grant receiver 820 may receive a DL grant from a base station, the DL grant indicating a set of DL resources for DL ​​transmission to a set of UEs including the UE.

[0135] The uplink resource identifier 825 may identify a set of UL resources for negative acknowledgment feedback information corresponding to the DL transmission based on the DL grant.

[0136] Monitoring component 830 can monitor the set of DL resources for DL ​​transmissions from the base station.

[0137] The feedback manager 835 may transmit a feedback message to the base station via the UL resource set based on the monitoring, wherein the feedback message indicates that reception of the DL transmission is unsuccessful.

[0138] The transmitter 840 may transmit signals generated by other components of the device 805. In some examples, the transmitter 840 may be co-located with the receiver 810 in a transceiver module. For example, the transmitter 840 may be a reference Fig.10 Examples of aspects of the described transceiver 1020. The transmitter 840 may utilize a single antenna or a collection of antennas.

[0139] Fig. 9 A block diagram 900 of a communication manager 905 supporting feedback for multicast communications in accordance with aspects of the present disclosure is shown. The communication manager 905 may be an example of aspects of the communication manager 715, the communication manager 815, or the communication manager 1010 described herein. The communication manager 905 may include a grant receiver 910, an uplink resource identifier 915, a monitoring component 920, a feedback manager 925, a decoder 930, and a beam manager 935. Each of these modules may communicate directly or indirectly with each other (e.g., via one or more buses).

[0140] The grant receiver 910 may receive a DL grant from a base station, the DL grant indicating a DL resource set for DL ​​transmission to a UE set including the UE. In some examples, the grant receiver 910 may receive the DL grant via a DL transmit beam configured for the UE set. In some examples, the grant receiver 910 may receive one or more additional DL grants via a corresponding DL transmit beam, wherein each additional DL grant indicates a corresponding additional DL resource set for DL ​​transmission. In some examples, the grant receiver 910 may receive a second DL grant from a base station, the second DL grant indicating a second DL resource set for retransmitting DL transmission to the UE in response to a feedback message. In some examples, the grant receiver 910 may receive the DL grant via a PDCCH. In some cases, the DL grant includes a UL resource indicator or a feedback timing indicator indicating a UL resource set. In some cases, the UL resource indicator includes a PUCCH resource indicator. In some cases, the feedback timing indicator includes a PDSCH to HARQ feedback timing indicator. In some cases, the UL resource indicator and / or the feedback timing indicator are included in the DCI containing the DL grant.

[0141] The uplink resource identifier 915 may identify a UL resource set for negative acknowledgement feedback information corresponding to the DL transmission based on the DL grant. In some examples, the uplink resource identifier 915 may identify an additional UL resource set for negative acknowledgement feedback information corresponding to the DL transmission based on one or more additional DL grants. In some cases, the UL resource set includes PUCCH, PUSCH, RACH, UL resources within the system bandwidth, UL resources outside the system bandwidth, or any combination thereof.

[0142] Monitoring component 920 may monitor a DL resource set for a DL transmission from a base station. In some examples, monitoring component 920 may monitor an additional DL resource set for a DL transmission from a base station. In some examples, monitoring component 920 may monitor a second DL resource set for a retransmission of a DL transmission. In some examples, monitoring component 920 may monitor a PDSCH for a DL transmission.

[0143] The feedback manager 925 may transmit a feedback message to the base station via the UL resource set based on the monitoring, wherein the feedback message indicates that the reception of the DL transmission was unsuccessful. In some examples, the feedback manager 925 may transmit an additional feedback message to the base station via the corresponding UL resource set based on monitoring the additional DL resource set, wherein the additional feedback message indicates that the reception of the DL transmission was unsuccessful. In some examples, the feedback manager 925 may transmit a feedback message set including the feedback message on the corresponding UL resource set for negative acknowledgement feedback information.

[0144] In some examples, the feedback manager 925 may transmit a feedback message via at least one UL transmit beam in the UL transmit beam set based on link quality. In some examples, the feedback manager 925 may transmit a feedback message based on determining that a decoding procedure for a DL transmission is unsuccessful. In some examples, the feedback manager 925 may transmit a second feedback message to the base station based on monitoring a second DL resource set via a second UL resource set indicated by a second DL grant for negatively acknowledging feedback information, wherein the feedback message indicates that reception of a retransmission is unsuccessful. In some cases, the feedback message includes a HARQ NACK message, a bit sequence, a message preamble, or a combination thereof.

[0145] Decoder 930 may combine information received via the additional DL resource set based on the monitoring. In some examples, decoder 930 may determine that reception of the DL transmission was unsuccessful based on the combining. In some examples, decoder 930 may determine that a decoding procedure for the DL transmission was unsuccessful based on the monitoring.

[0146] The beam manager 935 may measure the link quality of a UL transmit beam set configured for communication with a base station.

[0147] Fig.10 A diagram of a system 1000 including a device 1005 supporting feedback for multicast communications according to aspects of the present disclosure is shown. The device 1005 may be an example of or include components of a device 705, a device 805, or a UE 115 as described herein. The device 1005 may include components for two-way voice and data communications, including components for transmitting and receiving communications, including a communication manager 1010, an I / O controller 1015, a transceiver 1020, an antenna 1025, a memory 1030, and a processor 1040. These components may be in electronic communication via one or more buses (e.g., a bus 1045).

[0148] The communication manager 1010 can receive a DL grant from a base station, the DL grant indicating a DL resource set for DL ​​transmission to a set of UEs including the UE; identify a UL resource set for negative acknowledgment feedback information corresponding to the DL transmission based on the DL grant; monitor the DL resource set to find DL transmission from the base station; and transmit a feedback message to the base station via the UL resource set based on the monitoring, wherein the feedback message indicates that reception of the DL transmission was unsuccessful.

[0149] I / O controller 1015 can manage input and output signals of device 1005. I / O controller 1015 can also manage peripheral devices that are not integrated into device 1005. In some cases, I / O controller 1015 can represent a physical connection or port to an external peripheral device. In some cases, I / O controller 1015 can utilize an operating system, such as MS- OS / Or another known operating system. In other cases, I / O controller 1015 may represent or interact with a modem, keyboard, mouse, touch screen, or similar device. In some cases, I / O controller 1015 may be implemented as part of a processor. In some cases, a user may interact with device 1005 via I / O controller 1015 or via hardware components controlled by I / O controller 1015.

[0150] The transceiver 1020 can communicate bidirectionally via one or more antennas, wired or wireless links, as described above. For example, the transceiver 1020 may represent a wireless transceiver and can communicate bidirectionally with another wireless transceiver. The transceiver 1020 may also include a modem to modulate packets and provide the modulated packets to an antenna for transmission, and demodulate packets received from an antenna.

[0151] In some cases, device 1005 may include a single antenna 1025, or device 1005 may have more than one antenna 1025, which may be capable of transmitting or receiving multiple wireless transmissions concurrently.

[0152] Memory 1030 may include random access memory (RAM) and read-only memory (ROM). Memory 1030 may store computer-readable, computer-executable code 1035 including instructions that, when executed, cause the processor to perform the various functions described herein. In some cases, memory 1030 may include, among other things, a basic input / output system (BIOS), which may control basic hardware or software operations, such as interaction with peripheral components or devices.

[0153] Processor 1040 may include an intelligent hardware device (e.g., a general purpose processor, a DSP, a central processing unit (CPU), a microcontroller, an ASIC, an FPGA, a programmable logic device, a discrete gate or transistor logic component, a discrete hardware component, or any combination thereof). In some cases, processor 1040 may be configured to operate a memory array using a memory controller. In other cases, the memory controller may be integrated into processor 1040. Processor 1040 may be configured to execute computer-readable instructions stored in a memory (e.g., memory 1030) to cause device 1005 to perform various functions (e.g., functions or tasks to support feedback for multicast communication).

[0154] Based on determining the NACK feedback for the multicast transmission, the processor of UE 115 (e.g., controlling the receiver 710, the transmitter 720, or the transceiver 1020) can reliably obtain the multicast information. In addition, the processor of UE 115 can transmit the NACK feedback and monitor the subsequent DL transmission. The processor of UE 115 can turn on one or more processing units for monitoring the subsequent DL transmission, increase the processing clock, or similar mechanisms within UE 115. In this way, when the subsequent DL transmission is received, the processor can be ready to respond more efficiently by reducing the ramp-up of the processing power.

[0155] The code 1035 may include instructions for implementing various aspects of the present disclosure, including instructions for supporting wireless communications. The code 1035 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 1035 may not be directly executed by the processor 1040, but may cause a computer (e.g., when compiled and executed) to perform the functions described herein.

[0156] Fig.11 A block diagram 1100 of a device 1105 supporting feedback for multicast communications according to aspects of the present disclosure is shown. The device 1105 may be an example of aspects of a base station 105 as described herein. The device 1105 may include a receiver 1110, a communication manager 1115, and a transmitter 1120. The device 1105 may also include a processor. Each of these components may be in communication with each other (e.g., via one or more buses).

[0157] 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 feedback for multicast communications, etc.). The information may be passed to other components of the device 1105. The receiver 1110 may be a reference Fig.14 Examples of various aspects of the described transceiver 1420. The receiver 1110 may utilize a single antenna or a collection of antennas.

[0158] The communication manager 1115 may determine a DL resource set for a DL transmission to a set of UEs; determine a UL resource set for negative acknowledgement feedback information corresponding to the DL transmission; transmit a DL grant to the set of UEs, the DL grant indicating a DL resource set for the DL transmission and a UL resource set for negative acknowledgement feedback information corresponding to the DL transmission; and monitor the UL resource set for a feedback message from at least one UE in the set of UEs, wherein the feedback message indicates that reception of the DL transmission at the at least one UE was unsuccessful. The actions performed by the communication manager 1115 as described herein may be implemented to achieve one or more potential advantages. One implementation may allow the base station 105 to reduce system overhead by processing only NACK feedback from one or more UEs 115 supported by the base station. In such a scenario, the base station 105 may perform retransmission of multicast information to one or more UEs 115, which may allow the multicast information to be more efficiently acquired at the one or more UEs 115. Another implementation may provide improved quality of service and reliability at the base station 105 by ensuring that the multicast information is more reliably acquired at the UE 115. Communications manager 1115 may be an example of aspects of communications manager 1410 described herein.

[0159] The communication manager 1115 or its subcomponents may be implemented in hardware, in 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 communication manager 1115 or its subcomponents may be performed by a general purpose processor, DSP, ASIC, FPGA or other programmable logic device designed to perform the functions described in this disclosure, discrete gate or transistor logic, discrete hardware components, or any combination thereof.

[0160] The communication manager 1115 or its subcomponents may be physically located at various locations, including being distributed such that portions of the functionality are implemented by one or more physical components at different physical locations. In some examples, according to various aspects of the present disclosure, the communication manager 1115 or its subcomponents may be separate and distinct components. In some examples, according to various aspects of the present disclosure, the communication manager 1115 or its subcomponents may be combined with one or more other hardware components (including, but not limited to, I / O components, a transceiver, a network server, another computing device, one or more other components described in the present disclosure, or a combination thereof).

[0161] The transmitter 1120 may transmit signals generated by other components of the device 1105. In some examples, the transmitter 1120 may be co-located with the receiver 1110 in a transceiver module. For example, the transmitter 1120 may be a reference Fig.14Examples of aspects of the described transceiver 1420. The transmitter 1120 may utilize a single antenna or a collection of antennas.

[0162] Fig.12 A block diagram 1200 of a device 1205 supporting feedback for multicast communications according to aspects of the present disclosure is shown. The device 1205 may be an example of aspects of the device 1105 or base station 105 as described herein. The device 1205 may include a receiver 1210, a communication manager 1215, and a transmitter 1240. The device 1205 may also include a processor. Each of these components may be in communication with each other (e.g., via one or more buses).

[0163] The receiver 1210 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 feedback for multicast communications, etc.). The information may be passed to other components of the device 1205. The receiver 1210 may be a reference Fig.14 Examples of various aspects of the described transceiver 1420. The receiver 1210 may utilize a single antenna or a collection of antennas.

[0164] The communication manager 1215 may be an example of aspects of the communication manager 1115 as described herein. The communication manager 1215 may include a downlink resource component 1220, an uplink resource component 1225, a grant transmitter 1230, and a resource monitor 1235. The communication manager 1215 may be an example of aspects of the communication manager 1410 described herein.

[0165] Downlink resource component 1220 can determine a set of DL resources for DL ​​transmissions to a set of UEs.

[0166] The uplink resource component 1225 can determine a set of UL resources to use for negative acknowledgement feedback information corresponding to a DL transmission.

[0167] The grant transmitter 1230 may transmit a DL grant to the set of UEs, the DL grant indicating a DL resource set for DL ​​transmission and a UL resource set for negative acknowledgement feedback information corresponding to the DL transmission.

[0168] The grant monitor 1235 may monitor the UL resource set for a feedback message from at least one UE in the set of UEs, wherein the feedback message indicates that reception of the DL transmission at the at least one UE was unsuccessful.

[0169] Transmitter 1240 may transmit signals generated by other components of device 1205. In some examples, transmitter 1240 may be co-located with receiver 1210 in a transceiver module. For example, transmitter 1240 may be a reference Fig.14 Examples of various aspects of the described transceiver 1420. The transmitter 1240 may utilize a single antenna or a collection of antennas.

[0170] Fig.13 A block diagram 1300 of a communication manager 1305 supporting feedback for multicast communications in accordance with aspects of the present disclosure is shown. The communication manager 1305 may be an example of aspects of the communication manager 1115, the communication manager 1215, or the communication manager 1410 described herein. The communication manager 1305 may include a downlink resource component 1310, an uplink resource component 1315, a grant transmitter 1320, a resource monitor 1325, a transmit beam manager 1330, and a feedback receiver 1335. Each of these modules may communicate directly or indirectly with each other (e.g., via one or more buses).

[0171] Downlink resource component 1310 may determine a set of DL resources for DL ​​transmissions to a set of UEs. In some examples, downlink resource component 1310 may transmit the DL transmissions in a PDSCH.

[0172] The uplink resource component 1315 may determine a UL resource set for negative acknowledgement feedback information corresponding to a DL transmission. In some examples, the uplink resource component 1315 may determine a corresponding UL resource set for negative acknowledgement feedback information corresponding to a DL transmission for each UE in the UE set, wherein the DL grant indicates these corresponding UL resource sets. In some examples, the uplink resource component 1315 may determine a common sequence and a common time and frequency resource mapping for the UE set. In some examples, the uplink resource component 1315 may transmit an indication of the common sequence and the common time and frequency resource mapping to the UE set. In some cases, the UL resource set includes PUCCH, PUSCH, RACH, UL resources within the system bandwidth, UL resources outside the system bandwidth, or any combination thereof. In some cases, at least two UL resource sets in these corresponding UL resource sets overlap at least partially.

[0173] The grant transmitter 1320 may transmit a DL grant to the set of UEs, the DL grant indicating a DL resource set for DL ​​transmission and a UL resource set for negative acknowledgement feedback information corresponding to the DL transmission. In some examples, the grant transmitter 1320 may transmit the DL grant to the set of UEs via one or more DL transmit beams in the DL transmit beam set. In some examples, the grant transmitter 1320 may transmit one or more additional DL grants via corresponding DL transmit beams, wherein each additional DL grant indicates a corresponding DL resource set for DL ​​transmission and a corresponding UL resource set for negative acknowledgement feedback information corresponding to the DL transmission.

[0174] In some examples, the grant transmitter 1320 may transmit a second DL grant to the UE set, the second DL grant indicating a second DL resource set for retransmitting a DL transmission in response to a feedback message and a second UL resource set for negative acknowledgement feedback information corresponding to the retransmission. In some examples, the grant transmitter 1320 may transmit the second DL grant via a DL transmit beam and a DL resource. In some examples, the grant transmitter 1320 may transmit a DCI to the UE set, the DCI including a feedback timing indicator. In some examples, the grant transmitter 1320 may transmit a DL grant in a PDCCH. In some cases, the DL grant includes a UL resource indicator and / or a feedback timing indicator indicating a UL resource set. In some cases, the UL resource indicator includes a PUCCH resource indicator. In some cases, the feedback timing indicator includes a PDSCH to HARQ feedback timing indicator.

[0175] The grant monitor 1325 may monitor the UL resource set for a feedback message from at least one UE in the set of UEs, wherein the feedback message indicates that reception of a DL transmission at the at least one UE was unsuccessful. In some examples, the resource monitor 1325 may monitor the corresponding UL resource set for a feedback message from at least one UE, wherein the feedback message indicates that reception of a DL transmission at the at least one UE via one or more DL transmit beams was unsuccessful. In some cases, the feedback message includes a NACK message.

[0176] The transmit beam manager 1330 may determine a DL transmit beam set configured for the set of UEs. In some examples, the transmit beam manager 1330 may identify a DL transmit beam and a DL resource corresponding to a UL resource on which a feedback message from at least one UE is received.

[0177] The feedback receiver 1335 may receive a feedback message from at least one UE based on monitoring the UL resource set.

[0178] Fig.14 A diagram of a system 1400 including a device 1405 supporting feedback for multicast communications according to aspects of the present disclosure is shown. The device 1405 may be an example of or include components of a device 1105, a device 1205, or a base station 105 as described herein. The device 1405 may include components for two-way voice and data communications, including components for transmitting and receiving communications, including a communication manager 1410, a network communication manager 1415, a transceiver 1420, an antenna 1425, a memory 1430, a processor 1440, and an inter-station communication manager 1445. These components may be in electronic communication via one or more buses (e.g., a bus 1450).

[0179] The communication manager 1410 may determine a DL resource set for DL ​​transmission to a set of UEs; determine a UL resource set for negative acknowledgment feedback information corresponding to the DL transmission; transmit a DL grant to the set of UEs, the DL grant indicating the DL resource set for the DL transmission and the UL resource set for negative acknowledgment feedback information corresponding to the DL transmission; and monitor the UL resource set for a feedback message from at least one UE in the set of UEs, wherein the feedback message indicates that reception of the DL transmission at the at least one UE is unsuccessful.

[0180] The network communications manager 1415 may manage communications with the core network (eg, via one or more wired backhaul links). For example, the network communications manager 1415 may manage the delivery of data communications for client devices, such as one or more UEs 115.

[0181] The transceiver 1420 can communicate bidirectionally via one or more antennas, wired or wireless links, as described above. For example, the transceiver 1420 may represent a wireless transceiver and can communicate bidirectionally with another wireless transceiver. The transceiver 1420 may also include a modem to modulate packets and provide the modulated packets to an antenna for transmission, and demodulate packets received from an antenna.

[0182] In some cases, a wireless device may include a single antenna 1425. However, in some cases, the device may have more than one antenna 1425, which may be capable of transmitting or receiving multiple wireless transmissions concurrently.

[0183] Memory 1430 may include RAM, ROM, or a combination thereof. Memory 1430 may store computer readable code 1435 including instructions that, when executed by a processor (e.g., processor 1440), cause the device to perform various functions described herein. In some cases, memory 1430 may include, among other things, a BIOS that may control basic hardware or software operations, such as interaction with peripheral components or devices.

[0184] Processor 1440 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, a discrete gate or transistor logic component, a discrete hardware component, or any combination thereof). In some cases, processor 1440 may be configured to operate a memory array using a memory controller. In some cases, the memory controller may be integrated into processor 1440. Processor 1440 may be configured to execute computer-readable instructions stored in a memory (e.g., memory 1430) to cause device 1405 to perform various functions (e.g., functions or tasks to support feedback for multicast communication).

[0185] The inter-site communication manager 1445 may manage communications with other base stations 105 and may include a controller or scheduler for controlling communications with UE 115 in cooperation with other base stations 105. For example, the inter-site communication manager 1445 may coordinate the 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 1445 may provide an X2 interface within an LTE / LTE-A wireless communication network technology to provide communications between base stations 105.

[0186] The code 1435 may include instructions for implementing various aspects of the present disclosure, including instructions for supporting wireless communications. The code 1435 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 1435 may not be directly executed by the processor 1440, but may cause a computer (e.g., when compiled and executed) to perform the functions described herein.

[0187] Fig.15 1 is a flow chart illustrating a method 1500 for supporting feedback for multicast communications according to aspects of the present disclosure. The operations of the method 1500 may be implemented by a UE 115 or a component thereof as described herein. For example, the operations of the method 1500 may be implemented by a UE 115 or a component thereof as described herein. Figures 7 to 10 In some examples, the UE may execute an instruction set to control the functional elements of the UE to perform the following functions. Additionally or alternatively, the UE may use dedicated hardware to perform various aspects of the following functions.

[0188] At 1505, the UE may receive a DL grant from a base station, the DL grant indicating a DL resource set for DL ​​transmission to a set of UEs including the UE. The operations of 1505 may be performed according to the methods described herein. In some examples, aspects of the operations of 1505 may be performed as described in reference to Figures 7 to 10 The described grant is for the receiver to execute.

[0189] At 1550, the UE may identify a UL resource set for negative acknowledgement feedback information corresponding to the DL transmission based on the DL grant. The operations of 1510 may be performed according to the methods described herein. In some examples, aspects of the operations of 1510 may be performed as described with reference to Figures 7 to 10 The uplink resource identifier described is used to perform the above operation.

[0190] At 1515, the UE may monitor the DL resource set to find a DL transmission from the base station. The operations of 1515 may be performed according to the methods described herein. In some examples, aspects of the operations of 1515 may be performed as described with reference to Figures 7 to 10 The monitoring components described are performed.

[0191] At 1520, the UE may transmit a feedback message to the base station via the UL resource set based on the monitoring, wherein the feedback message indicates that reception of the DL transmission was unsuccessful. The operations of 1520 may be performed according to the methods described herein. In some examples, aspects of the operations of 1520 may be as described with reference to Figures 7 to 10 The described feedback manager is implemented.

[0192] Fig.16 1 is a flow chart illustrating a method 1600 for supporting feedback for multicast communications according to aspects of the present disclosure. The operations of the method 1600 may be implemented by a UE 115 or components thereof as described herein. For example, the operations of the method 1600 may be implemented by a UE 115 or components thereof as described herein. Figures 7 to 10 In some examples, the UE may execute an instruction set to control the functional elements of the UE to perform the following functions. Additionally or alternatively, the UE may use dedicated hardware to perform various aspects of the following functions.

[0193] At 1605, the UE may receive a DL grant from a base station, the DL grant indicating a DL resource set for DL ​​transmission to a set of UEs including the UE. The operations of 1605 may be performed according to the methods described herein. In some examples, aspects of the operations of 1605 may be performed as described in reference to Figures 7 to 10 The described grant is for the receiver to execute.

[0194] At 1610, the UE may receive the DL grant via a DL transmit beam configured for the UE set. The operations of 1610 may be performed according to the methods described herein. In some examples, aspects of the operations of 1610 may be performed as described in reference to Figures 7 to 10 The described grant is for the receiver to execute.

[0195] At 1615, the UE may receive one or more additional DL grants via corresponding DL transmit beams, wherein each additional DL grant indicates a corresponding additional DL resource set for DL ​​transmission. The operations of 1615 may be performed according to the methods described herein. In some examples, aspects of the operations of 1615 may be performed as described in reference to Figures 7 to 10 The described grant is for the receiver to execute.

[0196] At 1620, the UE may identify a UL resource set for negative acknowledgement feedback information corresponding to the DL transmission based on the DL grant. The operations of 1620 may be performed according to the methods described herein. In some examples, aspects of the operations of 1620 may be performed as described with reference to Figures 7 to 10 The uplink resource identifier described is used to perform the above operation.

[0197] At 1625, the UE may identify an additional UL resource set for negative acknowledgement feedback information corresponding to the DL transmission based on the one or more additional DL grants. The operations of 1625 may be performed according to the methods described herein. In some examples, aspects of the operations of 1625 may be performed as described with reference to Figures 7 to 10 The uplink resource identifier described is used to perform the above operation.

[0198] At 1630, the UE may monitor the DL resource set and the additional DL resource set to find a DL transmission from the base station. The operations of 1630 may be performed according to the methods described herein. In some examples, aspects of the operations of 1630 may be performed as described with reference to Figures 7 to 10 The monitoring components described are performed.

[0199] At 1635, the UE may transmit a feedback message to the base station via the UL resource set based on the monitoring, wherein the feedback message indicates that reception of the DL transmission was unsuccessful. The operations of 1640 may be performed according to the methods described herein. In some examples, aspects of the operations of 1640 may be as described with reference to Figures 7 to 10 The described feedback manager is implemented.

[0200] Fig.17 1 is a flow chart illustrating a method 1700 for supporting feedback for multicast communications according to aspects of the present disclosure. The operations of the method 1700 may be implemented by a UE 115 or components thereof as described herein. For example, the operations of the method 1700 may be implemented by a UE 115 or components thereof as described herein. Figures 7 to 10 In some examples, the UE may execute an instruction set to control the functional elements of the UE to perform the following functions. Additionally or alternatively, the UE may use dedicated hardware to perform various aspects of the following functions.

[0201] At 1705, the UE may receive a DL grant from a base station, the DL grant indicating a DL resource set for DL ​​transmission to a set of UEs including the UE. The operations of 1705 may be performed according to the methods described herein. In some examples, aspects of the operations of 1705 may be performed as described in reference to Figures 7 to 10 The described grant is for the receiver to execute.

[0202] At 1710, the UE may identify a UL resource set for negative acknowledgement feedback information corresponding to a DL transmission based on the DL grant. The operations of 1710 may be performed according to the methods described herein. In some examples, aspects of the operations of 1710 may be performed as described with reference to Figures 7 to 10 The uplink resource identifier described is used to perform the above operation.

[0203] At 1715, the UE may monitor the DL resource set to find a DL transmission from the base station. The operations of 1715 may be performed according to the methods described herein. In some examples, aspects of the operations of 1715 may be performed as described with reference to Figures 7 to 10 The monitoring components described are performed.

[0204] At 1720, the UE may transmit a feedback message to the base station via the UL resource set based on the monitoring, wherein the feedback message indicates that reception of the DL transmission was unsuccessful. The operations of 1720 may be performed according to the methods described herein. In some examples, aspects of the operations of 1720 may be as described with reference to Figures 7 to 10 The described feedback manager is implemented.

[0205] At 1725, the UE may receive a second DL grant from the base station, the second DL grant indicating a second DL resource set for retransmitting the DL transmission to the UE in response to the feedback message. The operations of 1725 may be performed according to the methods described herein. In some examples, aspects of the operations of 1725 may be performed as described in reference to Figures 7 to 10 The described grant is for the receiver to execute.

[0206] At 1730, the UE may monitor the second DL resource set to look for retransmissions of the DL transmission. The operations of 1730 may be performed according to the methods described herein. In some examples, aspects of the operations of 1730 may be as described with reference to Figures 7 to 10 The monitoring components described are performed.

[0207] Fig.18 1 is a flow chart illustrating a method 1800 for supporting feedback for multicast communications according to aspects of the present disclosure. The operations of the method 1800 may be implemented by a base station 105 or components thereof as described herein. For example, the operations of the method 1800 may be implemented by a base station 105 or components thereof as described herein. Figures 11 to 14 In some examples, the base station may execute an instruction set to control the functional elements of the base station to perform the functions described below. Additionally or alternatively, the base station may use dedicated hardware to perform various aspects of the functions described below.

[0208] At 1805, the base station may determine a set of DL resources for DL ​​transmission to the set of UEs. The operations of 1805 may be performed according to the methods described herein. In some examples, aspects of the operations of 1805 may be performed as described with reference to Figures 11 to 14 The described downlink resource components are performed.

[0209] At 1810, the base station may determine a UL resource set for negative acknowledgement feedback information corresponding to the DL transmission. The operations of 1810 may be performed according to the methods described herein. In some examples, aspects of the operations of 1810 may be performed as described with reference to Figures 11 to 14 The described uplink resource components are performed.

[0210] At 1815, the base station may transmit a DL grant to the set of UEs, the DL grant indicating a DL resource set for the DL transmission and a UL resource set for negative acknowledgement feedback information corresponding to the DL transmission. The operations of 1815 may be performed according to the methods described herein. In some examples, aspects of the operations of 1815 may be performed as described with reference to Figures 11 to 14 The described grant transmitter is executed.

[0211] At 1820, the base station may monitor the UL resource set for a feedback message from at least one UE in the set of UEs, wherein the feedback message indicates that reception of the DL transmission at the at least one UE is unsuccessful. The operations of 1820 may be performed according to the methods described herein. In some examples, aspects of the operations of 1820 may be performed as described with reference to Figures 11 to 14 The resource monitor described is executed.

[0212] Fig.19 1 is a flow chart illustrating a method 1900 for supporting feedback for multicast communications according to aspects of the present disclosure. The operations of the method 1900 may be implemented by a base station 105 or components thereof as described herein. For example, the operations of the method 1900 may be implemented by a base station 105 or components thereof as described herein. Figures 11 to 14 In some examples, the base station may execute an instruction set to control the functional elements of the base station to perform the functions described below. Additionally or alternatively, the base station may use dedicated hardware to perform various aspects of the functions described below.

[0213] At 1905, the base station may determine a DL transmit beam set configured for the set of UEs. The operations of 1905 may be performed according to the methods described herein. In some examples, aspects of the operations of 1905 may be performed as described in reference to Figures 11 to 14 The transmit beam manager described is executed.

[0214] At 1910, the base station may determine a DL resource set for DL ​​transmission to the set of UEs. The operations of 1910 may be performed according to the methods described herein. In some examples, aspects of the operations of 1910 may be performed as described with reference to Figures 11 to 14 The described downlink resource components are performed.

[0215] At 1915, the base station may determine a UL resource set for negative acknowledgement feedback information corresponding to the DL transmission. The operations of 1915 may be performed according to the methods described herein. In some examples, aspects of the operations of 1915 may be performed as described with reference to Figures 11 to 14 The described uplink resource components are performed.

[0216] At 1920, the base station may transmit a DL grant to the set of UEs via one or more DL transmit beams in the DL transmit beam set, the DL grant indicating a DL resource set for DL ​​transmission and a UL resource set for negative acknowledgement feedback information corresponding to the DL transmission. The operations of 1920 may be performed according to the methods described herein. In some examples, aspects of the operations of 1920 may be performed as described with reference to Figures 11 to 14 The described grant transmitter is executed.

[0217] At 1925, the base station may transmit one or more additional DL grants via corresponding DL transmit beams, wherein each additional DL grant indicates a corresponding DL resource set for DL ​​transmission and a corresponding UL resource set for negative acknowledgement feedback information corresponding to the DL transmission. The operations of 1930 may be performed according to the methods described herein. In some examples, aspects of the operations of 1930 may be performed as described with reference to Figures 11 to 14 The described grant transmitter is executed.

[0218] At 1930, the base station may monitor the UL resource set for a feedback message from at least one UE in the set of UEs, wherein the feedback message indicates that reception of the DL transmission at the at least one UE is unsuccessful. The operations of 1935 may be performed according to the methods described herein. In some examples, aspects of the operations of 1935 may be performed as described with reference to Figures 11 to 14 The resource monitor described is executed.

[0219] At 1935, the base station may monitor the corresponding UL resource set for a feedback message from at least one UE, wherein the feedback message indicates that reception of a DL transmission via one or more DL transmit beams at the at least one UE is unsuccessful. The operations of 1940 may be performed according to the methods described herein. In some examples, aspects of the operations of 1940 may be performed as described with reference to Figures 11 to 14 The resource monitor described is executed.

[0220] Fig. 20 1 is a flow chart illustrating a method 2000 for supporting feedback for multicast communications according to aspects of the present disclosure. The operations of the method 2000 may be implemented by a base station 105 or components thereof as described herein. For example, the operations of the method 2000 may be implemented by a base station 105 or components thereof as described herein. Figures 11 to 14 In some examples, the base station may execute an instruction set to control the functional elements of the base station to perform the functions described below. Additionally or alternatively, the base station may use dedicated hardware to perform various aspects of the functions described below.

[0221] At 2005, the base station may determine a set of DL resources for DL ​​transmission to the set of UEs. The operations of 2005 may be performed according to the methods described herein. In some examples, aspects of the operations of 2005 may be performed as described with reference to Figures 11 to 14 The described downlink resource components are performed.

[0222] At 2010, the base station may determine a UL resource set for negative acknowledgement feedback information corresponding to the DL transmission. The operations of 2010 may be performed according to the methods described herein. In some examples, aspects of the operations of 2010 may be performed as described with reference to Figures 11 to 14 The described uplink resource components are performed.

[0223] At 2015, the base station may transmit a DL grant to the set of UEs, the DL grant indicating a DL resource set for DL ​​transmission and a UL resource set for negative acknowledgement feedback information corresponding to the DL transmission. The operations of 2015 may be performed according to the methods described herein. In some examples, aspects of the operations of 2015 may be performed as described with reference to Figures 11 to 14 The described grant transmitter is executed.

[0224] At 2020, the base station may monitor the UL resource set to find a feedback message from at least one UE in the set of UEs, wherein the feedback message indicates that reception of the DL transmission at the at least one UE is unsuccessful. The operations of 2020 may be performed according to the methods described herein. In some examples, aspects of the operations of 2020 may be performed as described with reference to Figures 11 to 14 The resource monitor described is executed.

[0225] At 2025, the base station may receive a feedback message from at least one UE based on monitoring the UL resource set. The operations of 2025 may be performed according to the methods described herein. In some examples, aspects of the operations of 2025 may be performed as described with reference to Figures 11 to 14 The described feedback receiver is implemented.

[0226] At 2030, the base station may transmit a second DL grant to the set of UEs, the second DL grant indicating a second set of DL resources for retransmitting the DL transmission in response to the feedback message and a second set of UL resources for negative acknowledgement feedback information corresponding to the retransmission. The operations of 2030 may be performed according to the methods described herein. In some examples, aspects of the operations of 2030 may be performed as described with reference to Figures 11 to 14 The described grant transmitter is executed.

[0227] Fig.2121. A flow chart illustrating a method 2100 for supporting feedback for multicast communications according to aspects of the present disclosure is shown. The operations of the method 2100 may be implemented by a base station 105 or components thereof as described herein. For example, the operations of the method 2100 may be implemented by a base station 105 or components thereof as described herein. Figures 11 to 14 In some examples, the base station may execute an instruction set to control the functional elements of the base station to perform the functions described below. Additionally or alternatively, the base station may use dedicated hardware to perform various aspects of the functions described below.

[0228] At 2105, the base station may determine a set of DL resources for DL ​​transmission to the set of UEs. The operations of 2105 may be performed according to the methods described herein. In some examples, aspects of the operations of 2105 may be performed as described with reference to Figures 11 to 14 The described downlink resource components are performed.

[0229] At 2110, the base station may determine a UL resource set for negative acknowledgement feedback information corresponding to the DL transmission. The operations of 2110 may be performed according to the methods described herein. In some examples, aspects of the operations of 2110 may be performed as described with reference to Figures 11 to 14 The described uplink resource components are performed.

[0230] At 2115, the base station may determine, for each UE in the set of UEs, a corresponding UL resource set for negative acknowledgement feedback information corresponding to a DL transmission, wherein the DL grant indicates these corresponding UL resource sets. The operations of 2115 may be performed according to the methods described herein. In some examples, aspects of the operations of 2115 may be as described with reference to Figures 11 to 14 The described uplink resource components are performed.

[0231] At 2120, the base station may transmit a DL grant to the set of UEs, the DL grant indicating a DL resource set for DL ​​transmission and a UL resource set for negative acknowledgement feedback information corresponding to the DL transmission. The operations of 2120 may be performed according to the methods described herein. In some examples, aspects of the operations of 2120 may be performed as described with reference to Figures 11 to 14 The described grant transmitter is executed.

[0232] At 2125, the base station may monitor the UL resource set for a feedback message from at least one UE in the set of UEs, wherein the feedback message indicates that reception of the DL transmission at the at least one UE is unsuccessful. The operations of 2125 may be performed according to the methods described herein. In some examples, aspects of the operations of 2125 may be performed as described with reference to Figures 11 to 14 The resource monitor described is executed.

[0233] It should be noted that the methods described herein describe possible implementations, and that the various operations and steps may be rearranged or otherwise modified and other implementations are possible. Furthermore, aspects from two or more methods may be combined.

[0234] The technology described herein can be used in various wireless communication systems, such as code division multiple access (CDMA), time division multiple access (TDMA), frequency division multiple access (FDMA), orthogonal frequency division multiple access (OFDMA), single carrier frequency division multiple access (SC-FDMA) and other systems. CDMA systems can implement radio technologies such as CDMA2000, Universal Terrestrial Radio Access (UTRA). CDMA2000 covers IS-2000, IS-95 and IS-856 standards. IS-2000 versions are generally referred to as CDMA2000 1X, 1X, etc. IS-856 (TIA-856) is generally referred to as CDMA2000 1xEV-DO, High Rate Packet Data (HRPD), etc. UTRA includes Wideband CDMA (WCDMA) and other variants of CDMA. TDMA systems can implement radio technologies such as Global System for Mobile Communications (GSM).

[0235] OFDMA systems can implement radio technologies such as Ultra Mobile Broadband (UMB), Evolved UTRA (E-UTRA), Institute of Electrical and Electronics Engineers (IEEE) 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, Flash-OFDM, etc. UTRA and E-UTRA are part of Universal Mobile Telecommunications System (UMTS). LTE, LTE-A, and LTE-A Pro are versions of UMTS that use E-UTRA. UTRA, E-UTRA, UMTS, LTE, LTE-A, LTE-A Pro, NR, and GSM are described in documents from an organization named "3rd Generation Partnership Project" (3GPP). CDMA2000 and UMB are described in documents from an organization named "3rd Generation Partnership Project 2" (3GPP2). The techniques described herein may be used for systems and radio technologies mentioned herein as well as for other systems and radio technologies. Although aspects of LTE, LTE-A, LTE-A Pro, or NR systems may be described for example purposes and LTE, LTE-A, LTE-A Pro, or NR terminology may be used in much of the description, the techniques described herein may also be applicable to applications other than LTE, LTE-A, LTE-A Pro, or NR applications.

[0236] A macro cell generally covers a relatively large geographic area (e.g., a radius of several kilometers) and may allow unrestricted access by UEs with service subscriptions to a network provider. A small cell may be associated with a lower power base station (compared to a macro cell), and the small cell may operate in the same or different (e.g., licensed, unlicensed, etc.) frequency band as the macro cell. According to various examples, a small cell may include a pico cell, a femto cell, and a micro cell. A pico cell, for example, may cover a smaller geographic area and may allow unrestricted access by UEs with service subscriptions to a network provider. A femto cell may also cover a smaller geographic area (e.g., a residence) and may provide restricted access by UEs associated with the femto cell (e.g., UEs in a closed subscriber group (CSG), UEs of users in the residence, etc.). An eNB for a macro cell may be referred to as a macro eNB. An eNB for a small cell may be referred to as a small cell eNB, a pico eNB, a femto eNB, or a home eNB. An eNB may support one or more (eg, two, three, four, etc.) cells and may also support communication using one or more component carriers.

[0237] The wireless communication systems described herein may support synchronous or asynchronous operation. For synchronous operation, each base station may have similar frame timing, and transmissions from different base stations may be roughly aligned in time. For asynchronous operation, each base station may have different frame timing, and transmissions from different base stations may not be aligned in time. The techniques described herein may be used for synchronous or asynchronous operation.

[0238] The information and signals described herein may be represented using any of a variety of different techniques and technologies. For example, data, instructions, commands, information, signals, bits, symbols, and chips that may be referred to throughout this description may be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof.

[0239] The various illustrative blocks and modules described in conjunction with the disclosure herein may be implemented or executed with a general purpose processor, a DSP, an 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 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 (e.g., a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration).

[0240] 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 on or transmitted by a computer-readable medium as one or more instructions or codes. Other examples and implementations fall within the scope of the present 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, hardwiring, or any combination thereof. Features that implement the functions may also be physically located in various locations, including being distributed so that parts of the functions are implemented at different physical locations.

[0241] Computer-readable medium includes both non-transient computer storage medium and communication medium, and it includes any medium that facilitates computer program to transfer from one place to another.Non-transient storage medium can be any available medium that can be accessed by general or special-purpose computer.As an example and not limitation, non-transient computer-readable medium can include random access memory (RAM), read-only memory (ROM), electrically erasable programmable ROM (EEPROM), flash memory, compact disk (CD) ROM or other optical disk storage, disk storage or other magnetic storage device, or can be used to carry or store instruction or data structure form of desired program code means and can be accessed by general or special-purpose computer or general or special-purpose processor any other non-transient medium.Any connection is also properly referred to as computer-readable medium.For example, if software is transmitted from website, server or other remote source using coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL) or wireless technology such as infrared, radio and microwave, then the coaxial cable, fiber optic cable, twisted pair, DSL or wireless technology such as infrared, radio and microwave are just included in the definition of medium. Disk and disc as used herein include CDs, laser discs, optical discs, digital versatile discs (DVDs), floppy disks, and Blu-ray discs, 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.

[0242] As used herein (including in the claims), "or" used in a list of items (e.g., a list of items with a phrase such as "at least one of" or "one or more of") 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). Similarly, as used herein, the phrase "based on" should not be interpreted as referring to a closed set of conditions. For example, an exemplary step described as "based on condition A" may be based on both condition A and condition B without departing from the scope of the present 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."

[0243] In the accompanying drawings, similar components or features may have the same reference number. In addition, various components of the same type may be distinguished by following the reference number with a dash and a second reference number that distinguishes between similar components. If only the first reference number is used in the specification, the description may apply to any of the similar components having the same first reference number regardless of the second reference number, or other subsequent reference numbers.

[0244] 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 that fall within the scope of the claims. The term "exemplary" as used herein means "used as an example, instance, or illustration" and does not mean "better than" or "better than other examples." This detailed description includes specific details to provide an understanding of the described techniques. However, these techniques may be practiced without these specific details. In some instances, well-known structures and devices are shown in block diagram form to avoid obscuring the concepts of the described examples.

[0245] The description herein is provided to enable 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 universal principles defined herein may be applied to other variations without departing from the scope of the present disclosure. Thus, the present disclosure is not limited to the examples and designs described herein, but should be granted the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for wireless communication at a user equipment (UE), comprising: receiving a downlink grant from a base station, the downlink grant indicating a set of downlink resources for downlink transmission to a plurality of UEs including the UE, wherein the downlink grant further indicates a respective set of uplink resources for each of the plurality of UEs; identifying, based at least in part on the downlink grant, from the corresponding uplink resource sets, a set of uplink resources for negative acknowledgment feedback information corresponding to the downlink transmission for the UE; monitoring the set of downlink resources for the downlink transmission from the base station; Upon determining that the downlink transmission is successfully received, not sending a feedback message for the downlink transmission to the base station; as well as Upon determining that reception of the downlink transmission is unsuccessful, transmitting a feedback message to the base station via the set of uplink resources based at least in part on the monitoring, wherein the feedback message indicates that reception of the downlink transmission is unsuccessful.

2. The method of claim 1, further comprising: The downlink grant is received via a downlink transmit beam configured for the plurality of UEs.

3. The method of claim 2, further comprising: receiving one or more additional downlink grants via respective downlink transmit beams, wherein each additional downlink grant indicates a respective additional set of downlink resources for the downlink transmission; identifying, based at least in part on the one or more additional downlink grants, an additional set of uplink resources for negative-acknowledgement feedback information corresponding to the downlink transmission; as well as The corresponding set of additional downlink resources is monitored for the downlink transmission from the base station.

4. The method of claim 3, further comprising: An additional feedback message is transmitted to the base station via a corresponding additional set of uplink resources based at least in part on monitoring the corresponding additional set of downlink resources, wherein the additional feedback message indicates that reception of the downlink transmission was unsuccessful.

5. The method of claim 3, further comprising: combining information received via the respective additional sets of downlink resources based at least in part on the monitoring; determining, based at least in part on the combining, that reception of the downlink transmission was unsuccessful; as well as A feedback message set including the feedback message is transmitted on a corresponding additional uplink resource set used for negative acknowledgment feedback information.

6. The method of claim 3, further comprising: measuring a link quality of an uplink transmit beam set configured for communication with the base station; as well as The feedback message is transmitted via at least one uplink transmit beam in the set of uplink transmit beams based at least in part on the link quality.

7. The method of claim 1, further comprising: determining, based at least in part on the monitoring, that a decoding procedure for the downlink transmission was unsuccessful; as well as The feedback message is transmitted based at least in part on determining that the decoding procedure for the downlink transmission was unsuccessful.

8. The method of claim 1, further comprising: receiving a second downlink grant from the base station, the second downlink grant indicating a second set of downlink resources for retransmitting the downlink transmission to the UE in response to the feedback message; monitoring the second set of downlink resources for a retransmission of the downlink transmission; as well as A second feedback message is transmitted to the base station based at least in part on monitoring a second uplink resource set for negative acknowledgment feedback information indicated by the second downlink grant via the second downlink resource set, wherein the feedback message indicates that reception of the retransmission was unsuccessful.

9. The method of claim 1, wherein the uplink resource set comprises a physical uplink control channel (PUCCH), a physical uplink shared channel (PUSCH), a random access channel (RACH), uplink resources within a system bandwidth, uplink resources outside the system bandwidth, or any combination thereof.

10. The method of claim 1, further comprising: The downlink grant is received via a physical downlink control channel (PDCCH).

11. The method of claim 1 , wherein monitoring the set of downlink resources comprises: A Physical Downlink Shared Channel (PDSCH) is monitored for the downlink transmission.

12. The method of claim 1, wherein the feedback message comprises a hybrid automatic repeat request (HARQ) negative acknowledgement (NACK) message, a bit sequence, a message preamble, or a combination thereof.

13. The method of claim 1, wherein: The downlink grant includes an uplink resource indicator and a feedback timing indicator indicating the uplink resource set; The feedback timing indicator comprises a physical downlink shared channel (PDSCH) to a hybrid automatic repeat request (HARQ) feedback timing indicator; The uplink resource indicator comprises a physical uplink control channel (PUCCH) resource indicator; and The uplink resource indicator and the feedback timing indicator are included in downlink control information (DCI) including the downlink grant.

14. A method for wireless communication at a base station, comprising: determining a set of downlink resources for downlink transmission to a plurality of user equipments (UEs); determining, for each of the plurality of UEs, a corresponding set of uplink resources for negative acknowledgment feedback information corresponding to the downlink transmission; transmitting, to the plurality of UEs, a downlink grant indicating the set of downlink resources for the downlink transmission and the corresponding set of uplink resources for negative acknowledgment feedback information corresponding to the downlink transmission; as well as The corresponding uplink resource set is monitored for a feedback message from at least one UE of the plurality of UEs, wherein the feedback message indicates that reception of the downlink transmission at the at least one UE was unsuccessful, and wherein failure to receive the feedback message indicates that reception of the downlink transmission at the at least one UE was successful.

15. The method of claim 14, further comprising: determining a downlink transmit beam set configured for the plurality of UEs; as well as The downlink grants are transmitted to the plurality of UEs via one or more downlink transmit beams in the downlink transmit beam set.

16. The method of claim 15, further comprising: One or more additional downlink grants are transmitted via respective downlink transmit beams, wherein each additional downlink grant indicates a respective set of downlink resources for the downlink transmission and a respective set of additional uplink resources for negative acknowledgment feedback information corresponding to the downlink transmission.

17. The method of claim 16, further comprising: The corresponding additional uplink resource sets are monitored for the feedback message from the at least one UE, wherein the feedback message indicates that reception of the downlink transmission via the one or more downlink transmit beams at the at least one UE was unsuccessful.

18. The method of claim 14, further comprising: receiving the feedback message from the at least one UE based at least in part on monitoring the corresponding set of uplink resources; as well as A second downlink grant is transmitted to the plurality of UEs, the second downlink grant indicating a second set of downlink resources for retransmitting the downlink transmission in response to the feedback message and a second set of uplink resources for negative acknowledgment feedback information corresponding to the retransmission.

19. The method of claim 18, further comprising: identifying a downlink transmit beam and a downlink resource corresponding to an uplink resource on which the feedback message from the at least one UE is received; as well as The second downlink grant is transmitted via the downlink transmit beam and the downlink resources.

20. The method of claim 14, wherein the uplink resource set comprises a physical uplink control channel (PUCCH), a physical uplink shared channel (PUSCH), a random access channel (RACH), uplink resources within a system bandwidth, uplink resources outside the system bandwidth, or any combination thereof.

21. The method of claim 14, wherein at least two of the respective uplink resource sets at least partially overlap.

22. The method of claim 14, further comprising: determining a common sequence and a common time and frequency resource mapping for the plurality of UEs; as well as An indication of the common sequence and the common time and frequency resource mapping is transmitted to the plurality of UEs.

23. The method of claim 14, wherein: The downlink grant includes an uplink resource indicator and a feedback timing indicator indicating an uplink resource set in the corresponding uplink resource set; The feedback timing indicator comprises a physical downlink shared channel (PDSCH) to a hybrid automatic repeat request (HARQ) feedback timing indicator; and The uplink resource indicator comprises a physical uplink control channel (PUCCH) resource indicator.

24. The method of claim 23, further comprising: Downlink control information (DCI) is transmitted to the plurality of UEs, the DCI including the uplink resource indicator and the feedback timing indicator.

25. The method of claim 14, wherein transmitting the downlink grant comprises: The downlink grant is transmitted in a Physical Downlink Control Channel (PDCCH).

26. The method of claim 14, further comprising: The downlink transmission is transmitted in a Physical Downlink Shared Channel (PDSCH).

27. The method of claim 14, wherein the feedback message comprises a negative acknowledgement (NACK) message.

28. A user equipment (UE) for wireless communication, comprising: processor; a memory coupled to the processor; as well as instructions stored in the memory and executable by the processor to cause the UE to: receiving a downlink grant from a base station, the downlink grant indicating a set of downlink resources for downlink transmission to a plurality of UEs including the UE, wherein the downlink grant further indicates a respective set of uplink resources for each of the plurality of UEs; identifying, based at least in part on the downlink grant, from the corresponding uplink resource sets, a set of uplink resources for negative acknowledgment feedback information corresponding to the downlink transmission for the UE; monitoring the set of downlink resources for the downlink transmission from the base station; Upon determining that the downlink transmission is successfully received, not sending a feedback message for the downlink transmission to the base station; as well as Upon determining that reception of the downlink transmission is unsuccessful, transmitting a feedback message to the base station via the set of uplink resources based at least in part on the monitoring, wherein the feedback message indicates that reception of the downlink transmission is unsuccessful.

29. The UE of claim 28, wherein the instructions are further executable by the processor to cause the UE to: The downlink grant is received via a downlink transmit beam configured for the plurality of UEs.

30. The UE of claim 29, wherein the instructions are further executable by the processor to cause the UE to: receiving one or more additional downlink grants via respective downlink transmit beams, wherein each additional downlink grant indicates a respective additional set of downlink resources for the downlink transmission; identifying, based at least in part on the one or more additional downlink grants, an additional set of uplink resources for negative-acknowledgement feedback information corresponding to the downlink transmission; as well as The corresponding set of additional downlink resources is monitored for the downlink transmission from the base station.

31. The UE of claim 30, wherein the instructions are further executable by the processor to cause the UE to: An additional feedback message is transmitted to the base station via a corresponding additional set of uplink resources based at least in part on monitoring the corresponding additional set of downlink resources, wherein the additional feedback message indicates that reception of the downlink transmission was unsuccessful.

32. The UE of claim 30, wherein the instructions are further executable by the processor to cause the UE to: combining information received via the respective additional sets of downlink resources based at least in part on the monitoring; determining, based at least in part on the combining, that reception of the downlink transmission was unsuccessful; as well as A feedback message set including the feedback message is transmitted on a corresponding additional uplink resource set used for negative acknowledgment feedback information.

33. The UE of claim 29, wherein the instructions are further executable by the processor to cause the UE to: measuring a link quality of an uplink transmit beam set configured for communication with the base station; and The feedback message is transmitted via at least one uplink transmit beam in the set of uplink transmit beams based at least in part on the link quality.

34. The UE of claim 28, wherein the instructions are further executable by the processor to cause the UE to: determining, based at least in part on the monitoring, that a decoding procedure for the downlink transmission was unsuccessful; and The feedback message is transmitted based at least in part on determining that the decoding procedure for the downlink transmission was unsuccessful.

35. The UE of claim 28, wherein the instructions are further executable by the processor to cause the UE to: receiving a second downlink grant from the base station, the second downlink grant indicating a second set of downlink resources for retransmitting the downlink transmission to the UE in response to the feedback message; and The second set of downlink resources is monitored for a retransmission of the downlink transmission.

36. The UE of claim 35, wherein the instructions are further executable by the processor to cause the UE to: A second feedback message is transmitted to the base station based at least in part on monitoring a second uplink resource set for negative acknowledgment feedback information indicated by the second downlink grant via the second downlink resource set, wherein the feedback message indicates that reception of the retransmission was unsuccessful.

37. The UE of claim 28, wherein the uplink resource set comprises a physical uplink control channel (PUCCH), a physical uplink shared channel (PUSCH), a random access channel (RACH), uplink resources within a system bandwidth, uplink resources outside the system bandwidth, or any combination thereof.

38. The UE of claim 28, wherein the instructions are further executable by the processor to cause the UE to: The downlink grant is received via a physical downlink control channel (PDCCH).

39. The UE of claim 28, wherein the instructions for monitoring the downlink resource set are executable by the processor to cause the UE to: A Physical Downlink Shared Channel (PDSCH) is monitored for the downlink transmission.

40. The UE of claim 28, wherein the feedback message comprises a hybrid automatic repeat request (HARQ) negative acknowledgement (NACK) message, a bit sequence, a message preamble, or a combination thereof.

41. The UE of claim 28, wherein the downlink grant comprises a feedback timing indicator indicating the uplink resource set.

42. The UE of claim 41, wherein the feedback timing indicator comprises a physical downlink shared channel (PDSCH) to hybrid automatic repeat request (HARQ) feedback timing indicator.

43. The UE of claim 41, wherein the feedback timing indicator is included in downlink control information (DCI) containing the downlink grant.

44. An apparatus for wireless communication at a base station, comprising: processor; a memory coupled to the processor; as well as instructions stored in the memory and executable by the processor to cause the apparatus to: determining a set of downlink resources for downlink transmission to a plurality of user equipments (UEs); determining, for each of the plurality of UEs, a corresponding set of uplink resources for negative acknowledgment feedback information corresponding to the downlink transmission; transmitting, to the plurality of UEs, a downlink grant indicating the set of downlink resources for the downlink transmission and the corresponding set of uplink resources for negative acknowledgment feedback information corresponding to the downlink transmission; as well as The corresponding uplink resource set is monitored for a feedback message from at least one UE of the plurality of UEs, wherein the feedback message indicates that reception of the downlink transmission at the at least one UE was unsuccessful, and wherein failure to receive the feedback message indicates that reception of the downlink transmission at the at least one UE was successful.

45. The apparatus of claim 44, wherein the instructions are further executable by the processor to cause the apparatus to: determining a downlink transmit beam set configured for the plurality of UEs; and The downlink grants are transmitted to the plurality of UEs via one or more downlink transmit beams in the downlink transmit beam set.

46. ​​The apparatus of claim 45, wherein the instructions are further executable by the processor to cause the apparatus to: One or more additional downlink grants are transmitted via respective downlink transmit beams, wherein each additional downlink grant indicates a respective set of downlink resources for the downlink transmission and a respective set of additional uplink resources for negative acknowledgment feedback information corresponding to the downlink transmission.

47. The apparatus of claim 46, wherein the instructions are further executable by the processor to cause the apparatus to: The corresponding additional uplink resource sets are monitored for the feedback message from the at least one UE, wherein the feedback message indicates that reception of the downlink transmission via the one or more downlink transmit beams at the at least one UE was unsuccessful.

48. The apparatus of claim 44, wherein the instructions are further executable by the processor to cause the apparatus to: receiving the feedback message from the at least one UE based at least in part on monitoring the corresponding set of uplink resources; and A second downlink grant is transmitted to the plurality of UEs, the second downlink grant indicating a second set of downlink resources for retransmitting the downlink transmission in response to the feedback message and a second set of uplink resources for negative acknowledgment feedback information corresponding to the retransmission.

49. The apparatus of claim 48, wherein the instructions are further executable by the processor to cause the apparatus to: identifying a downlink transmit beam and a downlink resource corresponding to an uplink resource on which the feedback message from the at least one UE is received; and The second downlink grant is transmitted via the downlink transmit beam and the downlink resources.

50. The apparatus of claim 44, wherein the uplink resource set comprises a physical uplink control channel (PUCCH), a physical uplink shared channel (PUSCH), a random access channel (RACH), uplink resources within a system bandwidth, uplink resources outside the system bandwidth, or any combination thereof.

51. The apparatus of claim 44, wherein at least two of the respective uplink resource sets at least partially overlap.

52. The apparatus of claim 44, wherein the instructions are further executable by the processor to cause the apparatus to: determining a common sequence and a common time and frequency resource mapping for the plurality of UEs; and An indication of the common sequence and the common time and frequency resource mapping is transmitted to the plurality of UEs.

53. The apparatus of claim 44, wherein the downlink grant comprises a feedback timing indicator indicating an uplink resource set of the corresponding uplink resource sets.

54. The apparatus of claim 53, wherein the feedback timing indicator comprises a physical downlink shared channel (PDSCH) to hybrid automatic repeat request (HARQ) feedback timing indicator.

55. The apparatus of claim 53, wherein the instructions are further executable by the processor to cause the apparatus to: Downlink control information (DCI) is transmitted to the plurality of UEs, the DCI including the feedback timing indicator.

56. The apparatus of claim 44, wherein the instructions for transmitting the downlink grant are executable by the processor to cause the apparatus to: The downlink grant is transmitted in a Physical Downlink Control Channel (PDCCH).

57. The apparatus of claim 44, wherein the instructions are further executable by the processor to cause the apparatus to: The downlink transmission is transmitted in a Physical Downlink Shared Channel (PDSCH).

58. The apparatus of claim 44, wherein the feedback message comprises a negative acknowledgement (NACK) message.

59. A non-transitory computer-readable medium storing code for wireless communication at a user equipment (UE), the code comprising instructions executable by a processor to: receiving a downlink grant from a base station, the downlink grant indicating a set of downlink resources for downlink transmission to a plurality of UEs including the UE, wherein the downlink grant further indicates a respective set of uplink resources for each of the plurality of UEs; identifying, based at least in part on the downlink grant, from the corresponding uplink resource sets, a set of uplink resources for negative acknowledgment feedback information corresponding to the downlink transmission for the UE; monitoring the set of downlink resources for the downlink transmission from the base station; Upon determining that the downlink transmission is successfully received, not sending a feedback message for the downlink transmission to the base station; as well as Upon determining that reception of the downlink transmission is unsuccessful, transmitting a feedback message to the base station via the set of uplink resources based at least in part on the monitoring, wherein the feedback message indicates that reception of the downlink transmission is unsuccessful.

60. The non-transitory computer readable medium of claim 59, wherein the instructions are further executable to: The downlink grant is received via a downlink transmit beam configured for the plurality of UEs.

61. The non-transitory computer readable medium of claim 60, wherein the instructions are further executable to: receiving one or more additional downlink grants via respective downlink transmit beams, wherein each additional downlink grant indicates a respective additional set of downlink resources for the downlink transmission; identifying, based at least in part on the one or more additional downlink grants, an additional set of uplink resources for negative-acknowledgement feedback information corresponding to the downlink transmission; as well as The corresponding set of additional downlink resources is monitored for the downlink transmission from the base station.

62. The non-transitory computer readable medium of claim 61, wherein the instructions are further executable to: An additional feedback message is transmitted to the base station via a corresponding additional set of uplink resources based at least in part on monitoring the corresponding additional set of downlink resources, wherein the additional feedback message indicates that reception of the downlink transmission was unsuccessful.

63. The non-transitory computer readable medium of claim 61, wherein the instructions are further executable to: combining information received via the respective additional sets of downlink resources based at least in part on the monitoring; determining, based at least in part on the combining, that reception of the downlink transmission was unsuccessful; as well as A feedback message set including the feedback message is transmitted on a corresponding additional uplink resource set used for negative acknowledgment feedback information.

64. The non-transitory computer readable medium of claim 61, wherein the instructions are further executable to: measuring a link quality of an uplink transmit beam set configured for communication with the base station; and The feedback message is transmitted via at least one uplink transmit beam in the set of uplink transmit beams based at least in part on the link quality.

65. The non-transitory computer readable medium of claim 59, wherein the instructions are further executable to: determining, based at least in part on the monitoring, that a decoding procedure for the downlink transmission was unsuccessful; and The feedback message is transmitted based at least in part on determining that the decoding procedure for the downlink transmission was unsuccessful.

66. The non-transitory computer readable medium of claim 59, wherein the instructions are further executable to: receiving a second downlink grant from the base station, the second downlink grant indicating a second set of downlink resources for retransmitting the downlink transmission to the UE in response to the feedback message; and The second set of downlink resources is monitored for a retransmission of the downlink transmission.

67. The non-transitory computer readable medium of claim 66, wherein the instructions are further executable to: A second feedback message is transmitted to the base station based at least in part on monitoring a second uplink resource set for negative acknowledgment feedback information indicated by the second downlink grant via the second downlink resource set, wherein the feedback message indicates that reception of the retransmission was unsuccessful.

68. A non-transitory computer-readable medium as described in claim 59, wherein the uplink resource set includes a physical uplink control channel (PUCCH), a physical uplink shared channel (PUSCH), a random access channel (RACH), uplink resources within the system bandwidth, uplink resources outside the system bandwidth, or any combination thereof.

69. The non-transitory computer readable medium of claim 59, wherein the instructions are further executable to: The downlink grant is received via a physical downlink control channel (PDCCH).

70. The non-transitory computer readable medium of claim 59, wherein the instructions for monitoring the set of downlink resources are executable to: A Physical Downlink Shared Channel (PDSCH) is monitored for the downlink transmission.

71. The non-transitory computer-readable medium of claim 59, wherein the feedback message comprises a hybrid automatic repeat request (HARQ) negative acknowledgement (NACK) message, a bit sequence, a message preamble, or a combination thereof.

72. The non-transitory computer-readable medium of claim 59, wherein the downlink grant comprises a feedback timing indicator indicating the uplink resource set.

73. The non-transitory computer-readable medium of claim 72, wherein the feedback timing indicator comprises a physical downlink shared channel (PDSCH) to hybrid automatic repeat request (HARQ) feedback timing indicator.

74. The non-transitory computer-readable medium of claim 72, wherein the feedback timing indicator is included in downlink control information (DCI) containing the downlink grant.

75. A non-transitory computer-readable medium storing code for wireless communication at a base station, the code comprising instructions executable by a processor to: determining a set of downlink resources for downlink transmission to a plurality of user equipments (UEs); determining, for each of the plurality of UEs, a corresponding set of uplink resources for negative acknowledgment feedback information corresponding to the downlink transmission; transmitting, to the plurality of UEs, a downlink grant indicating the set of downlink resources for the downlink transmission and the corresponding set of uplink resources for negative acknowledgment feedback information corresponding to the downlink transmission; as well as The corresponding uplink resource set is monitored for a feedback message from at least one UE of the plurality of UEs, wherein the feedback message indicates that reception of the downlink transmission at the at least one UE was unsuccessful, and wherein failure to receive the feedback message indicates that reception of the downlink transmission at the at least one UE was successful.

76. The non-transitory computer readable medium of claim 75, wherein the instructions are further executable to: determining a downlink transmit beam set configured for the plurality of UEs; and The downlink grants are transmitted to the plurality of UEs via one or more downlink transmit beams in the downlink transmit beam set.

77. The non-transitory computer readable medium of claim 76, wherein the instructions are further executable to: One or more additional downlink grants are transmitted via respective downlink transmit beams, wherein each additional downlink grant indicates a respective set of downlink resources for the downlink transmission and a respective set of additional uplink resources for negative acknowledgment feedback information corresponding to the downlink transmission.

78. The non-transitory computer readable medium of claim 77, wherein the instructions are further executable to: The corresponding additional uplink resource sets are monitored for the feedback message from the at least one UE, wherein the feedback message indicates that reception of the downlink transmission via the one or more downlink transmit beams at the at least one UE was unsuccessful.

79. The non-transitory computer readable medium of claim 75, wherein the instructions are further executable to: receiving the feedback message from the at least one UE based at least in part on monitoring the corresponding set of uplink resources; and A second downlink grant is transmitted to the plurality of UEs, the second downlink grant indicating a second set of downlink resources for retransmitting the downlink transmission in response to the feedback message and a second set of uplink resources for negative acknowledgment feedback information corresponding to the retransmission.

80. The non-transitory computer readable medium of claim 79, wherein the instructions are further executable to: identifying a downlink transmit beam and a downlink resource corresponding to an uplink resource on which the feedback message from the at least one UE is received; and The second downlink grant is transmitted via the downlink transmit beam and the downlink resources.

81. A non-transitory computer-readable medium as described in claim 75, wherein the uplink resource set includes a physical uplink control channel (PUCCH), a physical uplink shared channel (PUSCH), a random access channel (RACH), uplink resources within the system bandwidth, uplink resources outside the system bandwidth, or any combination thereof.

82. The non-transitory computer-readable medium of claim 75, wherein at least two of the respective uplink resource sets at least partially overlap.

83. The non-transitory computer readable medium of claim 75, wherein the instructions are further executable to: determining a common sequence and a common time and frequency resource mapping for the plurality of UEs; and An indication of the common sequence and the common time and frequency resource mapping is transmitted to the plurality of UEs.

84. The non-transitory computer-readable medium of claim 75, wherein the downlink grant comprises a feedback timing indicator indicating an uplink resource set of the corresponding uplink resource sets.

85. The non-transitory computer-readable medium of claim 84, wherein the feedback timing indicator comprises a physical downlink shared channel (PDSCH) to hybrid automatic repeat request (HARQ) feedback timing indicator.

86. The non-transitory computer readable medium of claim 84, wherein the instructions are further executable to: Downlink control information (DCI) is transmitted to the plurality of UEs, the DCI including the feedback timing indicator.

87. The non-transitory computer readable medium of claim 75, wherein the instructions for transmitting the downlink grant are executable to: The downlink grant is transmitted in a Physical Downlink Control Channel (PDCCH).

88. The non-transitory computer readable medium of claim 75, wherein the instructions are further executable to: The downlink transmission is transmitted in a Physical Downlink Shared Channel (PDSCH).

89. The non-transitory computer-readable medium of claim 75, wherein the feedback message comprises a negative acknowledgement (NACK) message.

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