# Patent

## Title
Sequence-based hybrid automatic repeat request acknowledgement (HARQ-ACK) feedback

## Abstract

Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a user equipment (UE) may receive, from a base station, a plurality of downlink shared channel transmissions. The UE may transmit, to the base station, a sequence indicating that a hybrid automatic repeat request acknowledgement (ACK) feedback associated with the plurality of downlink shared channel transmissions includes only ACK bits for the plurality of downlink shared channel transmissions. Numerous other aspects are provided.

## Background
FIELD OF THE DISCLOSURE
Aspects of the present disclosure generally relate to wireless communication and to techniques and apparatuses for sequence-based hybrid automatic repeat request acknowledgement (HARQ-ACK) feedback.
BACKGROUND
Wireless communication systems are widely deployed to provide various telecommunication services such as telephony, video, data, messaging, and broadcasts. Typical wireless communication systems may employ multiple-access technologies capable of supporting communication with multiple users by sharing available system resources (e.g., bandwidth, transmit power, or the like). Examples of such multiple-access technologies include code division multiple access (CDMA) systems, time division multiple access (TDMA) systems, frequency-division multiple access (FDMA) systems, orthogonal frequency-division multiple access (OFDMA) systems, single-carrier frequency-division multiple access (SC-FDMA) systems, time division synchronous code division multiple access (TD-SCDMA) systems, and Long Term Evolution (LTE). LTE/LTE-Advanced is a set of enhancements to the Universal Mobile Telecommunications System (UMTS) mobile standard promulgated by the Third Generation Partnership Project (3GPP).
A wireless network may include a number of base stations (BSs) that can support communication for a number of user equipment (UEs). A user equipment (UE) may communicate with a base station (BS) via the downlink and uplink. The downlink (or forward link) refers to the communication link from the BS to the UE, and the uplink (or reverse link) refers to the communication link from the UE to the BS. As will be described in more detail herein, a BS may be referred to as a Node B, a gNB, an access point (AP), a radio head, a transmit receive point (TRP), a New Radio (NR) BS, a 5G Node B, or the like.
The above multiple access technologies have been adopted in various telecommunication standards to provide a common protocol that enables different user equipment to communicate on a municipal, national, regional, and even global level. New Radio (NR), which may also be referred to as 5G, is a set of enhancements to the LTE mobile standard promulgated by the Third Generation Partnership Project (3GPP). NR is designed to better support mobile broadband Internet access by improving spectral efficiency, lowering costs, improving services, making use of new spectrum, and better integrating with other open standards using orthogonal frequency division multiplexing (OFDM) with a cyclic prefix (CP) (CP-OFDM) on the downlink (DL), using CP-OFDM and/or SC-FDM (e.g., also known as discrete Fourier transform spread OFDM (DFT-s-OFDM)) on the uplink (UL), as well as supporting beamforming, multiple-input multiple-output (MIMO) antenna technology, and carrier aggregation. As the demand for mobile broadband access continues to increase, further improvements in LTE, NR, and other radio access technologies remain useful.
SUMMARY
In some aspects, a method of wireless communication performed by a user equipment (UE) includes receiving, from a base station, a plurality of downlink shared channel transmissions; and transmitting, to the base station, a sequence indicating that a hybrid automatic repeat request acknowledgement (HARQ-ACK) feedback associated with the plurality of downlink shared channel transmissions includes only acknowledgement (ACK) bits for the plurality of downlink shared channel transmissions.
In some aspects, a method of wireless communication performed by a base station includes transmitting, to a UE, a plurality of downlink shared channel transmissions; and receiving, from the UE, a sequence indicating that a HARQ-ACK feedback associated with the plurality of downlink shared channel transmissions includes only ACK bits for the plurality of downlink shared channel transmissions.
In some aspects, a UE for wireless communication includes a memory and one or more processors operatively coupled to the memory, the memory and the one or more processors configured to: receive, from a base station, a plurality of downlink shared channel transmissions; and transmit, to the base station, a sequence indicating that a HARQ-ACK feedback associated with the plurality of downlink shared channel transmissions includes only ACK bits for the plurality of downlink shared channel transmissions.
In some aspects, a base station for wireless communication includes a memory and one or more processors operatively coupled to the memory, the memory and the one or more processors configured to: transmit, to a UE, a plurality of downlink shared channel transmissions; and receive, from the UE, a sequence indicating that a HARQ-ACK feedback associated with the plurality of downlink shared channel transmissions includes only ACK bits for the plurality of downlink shared channel transmissions.
In some aspects, a non-transitory computer-readable medium storing a set of instructions for wireless communication includes one or more instructions that, when executed by one or more processors of a UE, cause the UE to: receive, from a base station, a plurality of downlink shared channel transmissions; and transmit, to the base station, a sequence indicating that a HARQ-ACK feedback associated with the plurality of downlink shared channel transmissions includes only ACK bits for the plurality of downlink shared channel transmissions.
In some aspects, a non-transitory computer-readable medium storing a set of instructions for wireless communication includes one or more instructions that, when executed by one or more processors of a base station, cause the base station to: transmit, to a UE, a plurality of downlink shared channel transmissions; and receive, from the UE, a sequence indicating that a HARQ-ACK feedback associated with the plurality of downlink shared channel transmissions includes only ACK bits for the plurality of downlink shared channel transmissions.
In some aspects, an apparatus for wireless communication includes means for receiving, from a base station, a plurality of downlink shared channel transmissions; and means for transmitting, to the base station, a sequence indicating that a HARQ-ACK feedback associated with the plurality of downlink shared channel transmissions includes only ACK bits for the plurality of downlink shared channel transmissions.
In some aspects, an apparatus for wireless communication includes means for transmitting, to a UE, a plurality of downlink shared channel transmissions; and means for receiving, from the UE, a sequence indicating that a HARQ-ACK feedback associated with the plurality of downlink shared channel transmissions includes only ACK bits for the plurality of downlink shared channel transmissions.
Aspects generally include a method, apparatus, system, computer program product, non-transitory computer-readable medium, user equipment, base station, wireless communication device, and/or processing system as substantially described herein with reference to and as illustrated by the drawings and specification.
The foregoing has outlined rather broadly the features and technical advantages of examples according to the disclosure in order that the detailed description that follows may be better understood. Additional features and advantages will be described hereinafter. The conception and specific examples disclosed may be readily utilized as a basis for modifying or designing other structures for carrying out the same purposes of the present disclosure. Such equivalent constructions do not depart from the scope of the appended claims. Characteristics of the concepts disclosed herein, both their organization and method of operation, together with associated advantages will be better understood from the following description when considered in connection with the accompanying figures. Each of the figures is provided for the purposes of illustration and description, and not as a definition of the limits of the claims.



BRIEF DESCRIPTION OF THE DRAWINGS
So that the above-recited features of the present disclosure can be understood in detail, a more particular description, briefly summarized above, may be had by reference to aspects, some of which are illustrated in the appended drawings. It is to be noted, however, that the appended drawings illustrate only certain typical aspects of this disclosure and are therefore not to be considered limiting of its scope, for the description may admit to other equally effective aspects. The same reference numbers in different drawings may identify the same or similar elements.
FIG. 1 is a diagram illustrating an example of a wireless network, in accordance with various aspects of the present disclosure.
FIG. 2 is a diagram illustrating an example of a base station in communication with a UE in a wireless network, in accordance with various aspects of the present disclosure.
FIG. 3 is a diagram illustrating an example of hybrid automatic repeat request acknowledgement (HARQ-ACK) feedback, in accordance with various aspects of the present disclosure.
FIG. 4 is a diagram illustrating an example associated with sequence-based HARQ-ACK feedback, in accordance with various aspects of the present disclosure.
FIGS. 5-6 are diagrams illustrating example processes associated with sequence-based HARQ-ACK feedback, in accordance with various aspects of the present disclosure.
FIGS. 7-8 are block diagrams of example apparatuses for wireless communication, in accordance with various aspects of the present disclosure.



DETAILED DESCRIPTION
Various aspects of the disclosure are described more fully hereinafter with reference to the accompanying drawings. This disclosure may, however, be embodied in many different forms and should not be construed as limited to any specific structure or function presented throughout this disclosure. Rather, these aspects are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art. Based on the teachings herein, one skilled in the art should appreciate that the scope of the disclosure is intended to cover any aspect of the disclosure disclosed herein, whether implemented independently of or combined with any other aspect of the disclosure. For example, an apparatus may be implemented or a method may be practiced using any number of the aspects set forth herein. In addition, the scope of the disclosure is intended to cover such an apparatus or method which is practiced using other structure, functionality, or structure and functionality in addition to or other than the various aspects of the disclosure set forth herein. It should be understood that any aspect of the disclosure disclosed herein may be embodied by one or more elements of a claim.
Several aspects of telecommunication systems will now be presented with reference to various apparatuses and techniques. These apparatuses and techniques will be described in the following detailed description and illustrated in the accompanying drawings by various blocks, modules, components, circuits, steps, processes, algorithms, or the like (collectively referred to as “elements”). These elements may be implemented using hardware, software, or combinations thereof. Whether such elements are implemented as hardware or software depends upon the particular application and design constraints imposed on the overall system.
It should be noted that while aspects may be described herein using terminology commonly associated with a 5G or NR radio access technology (RAT), aspects of the present disclosure can be applied to other RATs, such as a 3G RAT, a 4G RAT, and/or a RAT subsequent to 5G (e.g., 6G).
FIG. 1 is a diagram illustrating an example of a wireless network 100, in accordance with various aspects of the present disclosure. The wireless network 100 may be or may include elements of a 5G (NR) network and/or an LTE network, among other examples. The wireless network 100 may include a number of base stations 110 (shown as BS 110a, BS 110b, BS 110c, and BS 110d) and other network entities. A base station (BS) is an entity that communicates with user equipment (UEs) and may also be referred to as an NR BS, a Node B, a gNB, a 5G node B (NB), an access point, a transmit receive point (TRP), or the like. Each BS may provide communication coverage for a particular geographic area. In 3GPP, the term “cell” can refer to a coverage area of a BS and/or a BS subsystem serving this coverage area, depending on the context in which the term is used.
A BS may provide communication coverage for a macro cell, a pico cell, a femto cell, and/or another type of cell. A macro cell may cover a relatively large geographic area (e.g., several kilometers in radius) and may allow unrestricted access by UEs with service subscription. A pico cell may cover a relatively small geographic area and may allow unrestricted access by UEs with service subscription. A femto cell may cover a relatively small geographic area (e.g., a home) and may allow restricted access by UEs having association with the femto cell (e.g., UEs in a closed subscriber group (CSG)). ABS for a macro cell may be referred to as a macro BS. ABS for a pico cell may be referred to as a pico BS. A BS for a femto cell may be referred to as a femto BS or a home BS. In the example shown in FIG. 1, a BS 110a may be a macro BS for a macro cell 102a, a BS 110b may be a pico BS for a pico cell 102b, and a BS 110c may be a femto BS for a femto cell 102c. A BS may support one or multiple (e.g., three) cells. The terms “eNB”, “base station”, “NR BS”, “gNB”, “TRP”, “AP”, “node B”, “5G NB”, and “cell” may be used interchangeably herein.
In some aspects, a cell may not necessarily be stationary, and the geographic area of the cell may move according to the location of a mobile BS. In some aspects, the BSs may be interconnected to one another and/or to one or more other BSs or network nodes (not shown) in the wireless network 100 through various types of backhaul interfaces, such as a direct physical connection or a virtual network, using any suitable transport network.
Wireless network 100 may also include relay stations. A relay station is an entity that can receive a transmission of data from an upstream station (e.g., a BS or a UE) and send a transmission of the data to a downstream station (e.g., a UE or a BS). A relay station may also be a UE that can relay transmissions for other UEs. In the example shown in FIG. 1, a relay BS 110d may communicate with macro BS 110a and a UE 120d in order to facilitate communication between BS 110a and UE 120d. A relay BS may also be referred to as a relay station, a relay base station, a relay, or the like.
Wireless network 100 may be a heterogeneous network that includes BSs of different types, such as macro BSs, pico BSs, femto BSs, relay BSs, or the like. These different types of BSs may have different transmit power levels, different coverage areas, and different impacts on interference in wireless network 100. For example, macro BSs may have a high transmit power level (e.g., 5 to 40 watts) whereas pico BSs, femto BSs, and relay BSs may have lower transmit power levels (e.g., 0.1 to 2 watts).
A network controller 130 may couple to a set of BSs and may provide coordination and control for these BSs. Network controller 130 may communicate with the BSs via a backhaul. The BSs may also communicate with one another, directly or indirectly, via a wireless or wireline backhaul.
UEs 120 (e.g., 120a, 120b, 120c) may be dispersed throughout wireless network 100, and each UE may be stationary or mobile. A UE may also be referred to as an access terminal, a terminal, a mobile station, a subscriber unit, a station, or the like. A UE may be a cellular phone (e.g., a smart phone), a personal digital assistant (PDA), a wireless modem, a wireless communication device, a handheld device, a laptop computer, a cordless phone, a wireless local loop (WLL) station, a tablet, a camera, a gaming device, a netbook, a smartbook, an ultrabook, a medical device or equipment, biometric sensors/devices, wearable devices (smart watches, smart clothing, smart glasses, smart wrist bands, smart jewelry (e.g., smart ring, smart bracelet)), an entertainment device (e.g., a music or video device, or a satellite radio), a vehicular component or sensor, smart meters/sensors, industrial manufacturing equipment, a global positioning system device, or any other suitable device that is configured to communicate via a wireless or wired medium.
Some UEs may be considered machine-type communication (MTC) or evolved or enhanced machine-type communication (eMTC) UEs. MTC and eMTC UEs include, for example, robots, drones, remote devices, sensors, meters, monitors, and/or location tags, that may communicate with a base station, another device (e.g., remote device), or some other entity. A wireless node may provide, for example, connectivity for or to a network (e.g., a wide area network such as Internet or a cellular network) via a wired or wireless communication link. Some UEs may be considered Internet-of-Things (IoT) devices, and/or may be implemented as NB-IoT (narrowband internet of things) devices. Some UEs may be considered a Customer Premises Equipment (CPE). UE 120 may be included inside a housing that houses components of UE 120, such as processor components and/or memory components. In some aspects, the processor components and the memory components may be coupled together. For example, the processor components (e.g., one or more processors) and the memory components (e.g., a memory) may be operatively coupled, communicatively coupled, electronically coupled, and/or electrically coupled.
In general, any number of wireless networks may be deployed in a given geographic area. Each wireless network may support a particular RAT and may operate on one or more frequencies. A RAT may also be referred to as a radio technology, an air interface, or the like. A frequency may also be referred to as a carrier, a frequency channel, or the like. Each frequency may support a single RAT in a given geographic area in order to avoid interference between wireless networks of different RATs. In some cases, NR or 5G RAT networks may be deployed.
In some aspects, two or more UEs 120 (e.g., shown as UE 120a and UE 120e) may communicate directly using one or more sidelink channels (e.g., without using a base station 110 as an intermediary to communicate with one another). For example, the UEs 120 may communicate using peer-to-peer (P2P) communications, device-to-device (D2D) communications, a vehicle-to-everything (V2X) protocol (e.g., which may include a vehicle-to-vehicle (V2V) protocol or a vehicle-to-infrastructure (V2I) protocol), and/or a mesh network. In this case, the UE 120 may perform scheduling operations, resource selection operations, and/or other operations described elsewhere herein as being performed by the base station 110.
Devices of wireless network 100 may communicate using the electromagnetic spectrum, which may be subdivided based on frequency or wavelength into various classes, bands, channels, or the like. For example, devices of wireless network 100 may communicate using an operating band having a first frequency range (FR1), which may span from 410 MHz to 7.125 GHz, and/or may communicate using an operating band having a second frequency range (FR2), which may span from 24.25 GHz to 52.6 GHz. The frequencies between FR1 and FR2 are sometimes referred to as mid-band frequencies. Although a portion of FR1 is greater than 6 GHz, FR1 is often referred to as a “sub-6 GHz” band. Similarly, FR2 is often referred to as a “millimeter wave” band despite being different from the extremely high frequency (EHF) band (30 GHz-300 GHz) which is identified by the International Telecommunications Union (ITU) as a “millimeter wave” band. Thus, unless specifically stated otherwise, it should be understood that the term “sub-6 GHz” or the like, if used herein, may broadly represent frequencies less than 6 GHz, frequencies within FR1, and/or mid-band frequencies (e.g., greater than 7.125 GHz). Similarly, unless specifically stated otherwise, it should be understood that the term “millimeter wave” or the like, if used herein, may broadly represent frequencies within the EHF band, frequencies within FR2, and/or mid-band frequencies (e.g., less than 24.25 GHz). It is contemplated that the frequencies included in FR1 and FR2 may be modified, and techniques described herein are applicable to those modified frequency ranges.
As indicated above, FIG. 1 is provided as an example. Other examples may differ from what is described with regard to FIG. 1.
FIG. 2 is a diagram illustrating an example 200 of a base station 110 in communication with a UE 120 in a wireless network 100, in accordance with various aspects of the present disclosure. Base station 110 may be equipped with T antennas 234a through 234t, and UE 120 may be equipped with R antennas 252a through 252r, where in general T≥1 and R≥1.
At base station 110, a transmit processor 220 may receive data from a data source 212 for one or more UEs, select one or more modulation and coding schemes (MCS) for each UE based at least in part on channel quality indicators (CQIs) received from the UE, process (e.g., encode and modulate) the data for each UE based at least in part on the MCS(s) selected for the UE, and provide data symbols for all UEs. Transmit processor 220 may also process system information (e.g., for semi-static resource partitioning information (SRPI)) and control information (e.g., CQI requests, grants, and/or upper layer signaling) and provide overhead symbols and control symbols. Transmit processor 220 may also generate reference symbols for reference signals (e.g., a cell-specific reference signal (CRS) or a demodulation reference signal (DMRS)) and synchronization signals (e.g., a primary synchronization signal (PSS) or a secondary synchronization signal (SSS)). A transmit (TX) multiple-input multiple-output (MIMO) processor 230 may perform spatial processing (e.g., precoding) on the data symbols, the control symbols, the overhead symbols, and/or the reference symbols, if applicable, and may provide T output symbol streams to T modulators (MODs) 232a through 232t. Each modulator 232 may process a respective output symbol stream (e.g., for OFDM) to obtain an output sample stream. Each modulator 232 may further process (e.g., convert to analog, amplify, filter, and upconvert) the output sample stream to obtain a downlink signal. T downlink signals from modulators 232a through 232t may be transmitted via T antennas 234a through 234t, respectively.
At UE 120, antennas 252a through 252r may receive the downlink signals from base station 110 and/or other base stations and may provide received signals to demodulators (DEMODs) 254a through 254r, respectively. Each demodulator 254 may condition (e.g., filter, amplify, downconvert, and digitize) a received signal to obtain input samples. Each demodulator 254 may further process the input samples (e.g., for OFDM) to obtain received symbols. A MIMO detector 256 may obtain received symbols from all R demodulators 254a through 254r, perform MIMO detection on the received symbols if applicable, and provide detected symbols. A receive processor 258 may process (e.g., demodulate and decode) the detected symbols, provide decoded data for UE 120 to a data sink 260, and provide decoded control information and system information to a controller/processor 280. The term “controller/processor” may refer to one or more controllers, one or more processors, or a combination thereof. A channel processor may determine a reference signal received power (RSRP) parameter, a received signal strength indicator (RSSI) parameter, a reference signal received quality (RSRQ) parameter, and/or a channel quality indicator (CQI) parameter, among other examples. In some aspects, one or more components of UE 120 may be included in a housing 284.
Network controller 130 may include communication unit 294, controller/processor 290, and memory 292. Network controller 130 may include, for example, one or more devices in a core network. Network controller 130 may communicate with base station 110 via communication unit 294.
On the uplink, at UE 120, a transmit processor 264 may receive and process data from a data source 262 and control information (e.g., for reports that include RSRP, RSSI, RSRQ, and/or CQI) from controller/processor 280. Transmit processor 264 may also generate reference symbols for one or more reference signals. The symbols from transmit processor 264 may be precoded by a TX MIMO processor 266 if applicable, further processed by modulators 254a through 254r (e.g., for DFT-s-OFDM or CP-OFDM), and transmitted to base station 110. In some aspects, a modulator and a demodulator (e.g., MOD/DEMOD 254) of the UE 120 may be included in a modem of the UE 120. In some aspects, the UE 120 includes a transceiver. The transceiver may include any combination of antenna(s) 252, modulators and/or demodulators 254, MIMO detector 256, receive processor 258, transmit processor 264, and/or TX MIMO processor 266. The transceiver may be used by a processor (e.g., controller/processor 280) and memory 282 to perform aspects of any of the methods described herein, for example, as described with reference to FIGS. 4-6.
At base station 110, the uplink signals from UE 120 and other UEs may be received by antennas 234, processed by demodulators 232, detected by a MIMO detector 236 if applicable, and further processed by a receive processor 238 to obtain decoded data and control information sent by UE 120. Receive processor 238 may provide the decoded data to a data sink 239 and the decoded control information to controller/processor 240. Base station 110 may include communication unit 244 and communicate to network controller 130 via communication unit 244. Base station 110 may include a scheduler 246 to schedule UEs 120 for downlink and/or uplink communications. In some aspects, a modulator and a demodulator (e.g., MOD/DEMOD 232) of the base station 110 may be included in a modem of the base station 110. In some aspects, the base station 110 includes a transceiver. The transceiver may include any combination of antenna(s) 234, modulators and/or demodulators 232, MIMO detector 236, receive processor 238, transmit processor 220, and/or TX MIMO processor 230. The transceiver may be used by a processor (e.g., controller/processor 240) and memory 242 to perform aspects of any of the methods described herein, for example, as described with reference to FIGS. 4-6.
Controller/processor 240 of base station 110, controller/processor 280 of UE 120, and/or any other component(s) of FIG. 2 may perform one or more techniques associated with sequence-based hybrid automatic repeat request acknowledgement (HARQ-ACK) feedback, as described in more detail elsewhere herein. For example, controller/processor 240 of base station 110, controller/processor 280 of UE 120, and/or any other component(s) of FIG. 2 may perform or direct operations of, for example, process 500 of FIG. 5, process 600 of FIG. 6, and/or other processes as described herein. Memories 242 and 282 may store data and program codes for base station 110 and UE 120, respectively. In some aspects, memory 242 and/or memory 282 may include a non-transitory computer-readable medium storing one or more instructions (e.g., code and/or program code) for wireless communication. For example, the one or more instructions, when executed (e.g., directly, or after compiling, converting, and/or interpreting) by one or more processors of the base station 110 and/or the UE 120, may cause the one or more processors, the UE 120, and/or the base station 110 to perform or direct operations of, for example, process 500 of FIG. 5, process 600 of FIG. 6, and/or other processes as described herein. In some aspects, executing instructions may include running the instructions, converting the instructions, compiling the instructions, and/or interpreting the instructions, among other examples.
In some aspects, a UE includes means for receiving, from a base station, a plurality of downlink shared channel transmissions; and/or means for transmitting, to the base station, a sequence indicating that a HARQ-ACK feedback associated with the plurality of downlink shared channel transmissions includes only acknowledgement (ACK) bits for the plurality of downlink shared channel transmissions. The means for the UE to perform operations described herein may include, for example, one or more of antenna 252, demodulator 254, MIMO detector 256, receive processor 258, transmit processor 264, TX MIMO processor 266, modulator 254, controller/processor 280, or memory 282.
In some aspects, the UE includes means for transmitting the sequence using an uplink control channel resource via an uplink control channel.
In some aspects, a base station includes means for transmitting, to a UE, a plurality of downlink shared channel transmissions; and/or means for receiving, from the UE, a sequence indicating that a HARQ-ACK feedback associated with the plurality of downlink shared channel transmissions includes only ACK bits for the plurality of downlink shared channel transmissions. The means for the base station to perform operations described herein may include, for example, one or more of transmit processor 220, TX MIMO processor 230, modulator 232, antenna 234, demodulator 232, MIMO detector 236, receive processor 238, controller/processor 240, memory 242, or scheduler 246.
In some aspects, the base station includes means for receiving the sequence via an uplink control channel using an uplink control channel resource.
While blocks in FIG. 2 are illustrated as distinct components, the functions described above with respect to the blocks may be implemented in a single hardware, software, or combination component or in various combinations of components. For example, the functions described with respect to the transmit processor 264, the receive processor 258, and/or the TX MIMO processor 266 may be performed by or under the control of controller/processor 280.
As indicated above, FIG. 2 is provided as an example. Other examples may differ from what is described with regard to FIG. 2.
FIG. 3 is a diagram illustrating an example 300 of HARQ-ACK feedback, in accordance with various aspects of the present disclosure.
As shown by reference number 302, the base station may transmit downlink semi-persistent scheduling (SPS) signaling to the UE. The SPS signaling may serve to schedule physical downlink shared channel (PDSCH) transmissions for the UE. The base station may perform the SPS signaling by transmitting radio resource control (RRC) message(s) to the UE. In some aspects, the UE may not successfully receive and decode the downlink SPS signaling. In this case, the UE may associate a negative acknowledgement (NACK) with the downlink SPS signaling. In other words, the UE may associate all NACK HARQ-ACK bits for a codeword associated with the downlink SPS signaling.
As shown by reference number 304, the UE may determine to skip a HARQ-ACK feedback for the downlink SPS signaling when all HARQ-ACK bits associated with the downlink SPS signaling are NACK. In other words, the UE may support skipping HARQ-ACK feedback for a codebook with only downlink SPS HARQ-ACK feedback, when all HARQ-ACK bits in the codebook are NACK. When the HARQ-ACK feedback for the downlink SPS signaling would contain NACK bits and no ACK bits (e.g., only NACK bits), the UE may skip the HARQ-ACK feedback, which may save power at the UE and reduce uplink interference with other UEs.
As shown by reference number 306, the base station may determine that no HARQ-ACK feedback transmission is received from the UE at a HARQ-ACK feedback occasion. The base station may determine that no HARQ-ACK feedback transmission is received from the UE that corresponds to the downlink SPS signaling. The base station may associate a discontinuous transmission (DTX) with the HARQ-ACK feedback occasion when no HARQ-ACK feedback transmission is received at the HARQ-ACK feedback occasion.
As shown by reference number 308, the base station may determine, based at least in part on no receipt of the HARQ-ACK feedback transmission at the HARQ-ACK feedback occasion, that all HARQ-ACK bits in the codebook with only downlink SPS HARQ-ACK feedback are NACK. In other words, the base station may determine, based at least in part on no receipt of the HARQ-ACK feedback transmission at the HARQ-ACK feedback occasion, that the downlink SPS signaling is associated with a NACK.
As indicated above, FIG. 3 is provided as an example. Other examples may differ from what is described with regard to FIG. 3.
A UE may skip a HARQ-ACK feedback transmission when all HARQ-ACK bits associated with downlink SPS signaling are NACK. In other words, the UE may associate the NACK with downlink SPS signaling that is not successfully received and/or decoded, but the UE may not transmit the HARQ-ACK feedback with the NACK to the base station. The base station may infer that all HARQ-ACK bits associated with downlink SPS signaling are NACK based at least in part on a subsequent DTX. However, this solution does not cover the situation in which all HARQ-ACK bits associated with downlink shared channel signaling are ACK.
In various aspects of techniques and apparatuses described herein, a UE may receive a plurality of PDSCH transmissions from a base station. The plurality of PDSCH transmissions may be associated with ultra-reliable low latency communications (URLLC). The UE may transmit, to the base station, a sequence indicating that a HARQ-ACK feedback associated with the plurality of PDSCH transmissions includes only ACK bits for the plurality of PDSCH transmissions. In other words, the UE may transmit the sequence to indicate that the plurality of PDSCH transmissions were successfully received at the UE, rather than transmit HARQ-ACK feedback that includes multiple ACK bits corresponding to the plurality of PDSCH transmissions. Alternatively, the UE may transmit, to the base station, a sequence indicating that a HARQ-ACK feedback associated with the plurality of PDSCH transmissions includes no NACK bits for the plurality of PDSCH transmissions. The UE may transmit the sequence via a physical uplink control channel (PUCCH) using a PUCCH resource. In some aspects, the sequence may represent one bit, which may reduce a signaling overhead and improve reliability.
In various aspects of techniques and apparatuses described herein, an uplink payload may be reduced by not transmitting ACK bits individually for a successful downlink transmission. Instead, the UE may transmit a shorter sequence representing all-ACK feedback to save on the upload payload, where the shorter sequence occupies less information than the ACK bits.
FIG. 4 is a diagram illustrating an example 400 associated with sequence-based HARQ-ACK feedback, in accordance with various aspects of the present disclosure. As shown in FIG. 4, example 400 includes communication between a UE (e.g., UE 120) and a base station (e.g., base station 110). In some aspects, the UE and the base station may be included in a wireless network such as wireless network 100.
As shown by reference 402, a UE may receive, from a base station, a plurality of PDSCH transmissions. The base station may transmit the plurality of PDSCH transmissions to the UE. The UE and/or the base station may be configured to support URLLC. For example, the UE may be a latency-sensitive connected device, and may be used, for example, in factory automation, autonomous driving, etc.
As shown by reference 404, the UE may determine that a HARQ-ACK feedback associated with the plurality of PDSCH transmissions includes only ACK bits. In other words, the UE may successfully receive and decode the plurality of PDSCH transmissions, so the UE may associate all ACK HARQ-ACK bits for the plurality of PDSCH transmissions.
As shown by reference number 406, the UE may transmit, to the base station, a sequence indicating that a HARQ-ACK feedback associated with the plurality of PDSCH transmissions includes only ACK bits for the plurality of PDSCH transmissions. The UE may transmit the sequence via a PUCCH using a PUCCH resource. The UE may transmit the sequence to indicate that the plurality of PDSCH transmissions are associated with only ACK bits. The UE may transmit the sequence rather than transmitting multiple ACK bits corresponding to the plurality of PDSCH transmissions successfully received at the UE. The sequence may be predefined in a specification, and thus may be known to the UE and/or the base station. As a result, a signaling overhead for the UE may be reduced, thereby improving reliability. The sequence may effectively function as a low-overhead HARQ-ACK feedback, but may involve less signaling overhead as compared to transmitting, to the base station, a HARQ-ACK feedback having multiple ACK bits.
In some aspects, the UE may transmit, to the base station, a sequence indicating that a HARQ-ACK feedback associated with the plurality of PDSCH transmissions includes no NACK bits for the plurality of PDSCH transmissions. In other words, the sequence may indicate that the HARQ-ACK feedback includes no NACK bits.
In some aspects, the sequence may be a predefined sequence that represents one bit. As an example, the sequence may be a pseudo-random sequence, such as a Gold sequence or a Zadoff-Chu sequence.
In some aspects, the base station may determine, based at least in part on the sequence, that all HARQ-ACK bits associated with the plurality of PDSCH transmissions are ACK bits. In other words, the base station may determine, based at least in part on the sequence, that the plurality of PDSCH transmissions are associated with ACKs. The sequence may be associated with all ACK HARQ-ACK bits for the plurality of PDSCH transmissions. The base station may receive the sequence rather than a HARQ-ACK feedback having multiple ACK bits, and the sequence may effectively serve as the HARQ-ACK feedback.
In some aspects, the UE may transmit the sequence using the PUCCH resource. A symbol length associated with the PUCCH resource carrying the sequence may be less than a symbol length associated an original PUCCH resource expected to carry multiple ACK bits. As a result, the sequence may reduce an uplink interference with other UEs, since the PUCCH resource carrying the sequence may be shorter in symbol length than the original PUCCH resource, where the original PUCCH resource may be transmitted in a format with 14 symbols.
In some aspects, the PUCCH resource carrying the sequence may not be configured to carry additional uplink control information (UCI) bits. The PUCCH resource carrying the sequence may not be configured to carry a channel state information (CSI) report. The PUCCH resource carrying the sequence may not be configured to carry a scheduling request (SR). In other words, the PUCCH resource associated with transmitting the sequence may be expected to carry ACK/NACK bits only, and may not carry the additional UCI bits, the CSI report, and/or the SR. The additional UCI bits, the CSI report, and/or the SR may not be multiplexed on the PUCCH resource carrying the sequence. Further, a symbol length associated with the PUCCH resource carrying the sequence may be less than a symbol length (e.g., 14 symbols) associated with a format of the original PUCCH resource.
As indicated above, FIG. 4 is provided as an example. Other examples may differ from what is described with regard to FIG. 4.
FIG. 5 is a diagram illustrating an example process 500 performed, for example, by a UE, in accordance with various aspects of the present disclosure. Example process 500 is an example where the UE (e.g., UE 120) performs operations associated with sequence-based HARQ-ACK feedback.
As shown in FIG. 5, in some aspects, process 500 may include receiving, from a base station, a plurality of downlink shared channel transmissions (block 510). For example, the UE (e.g., using reception component 702, depicted in FIG. 7) may receive, from a base station, a plurality of downlink shared channel transmissions, as described above.
As further shown in FIG. 5, in some aspects, process 500 may include transmitting, to the base station, a sequence indicating that a HARQ-ACK feedback associated with the plurality of downlink shared channel transmissions includes only ACK bits for the plurality of downlink shared channel transmissions (block 520). For example, the UE (e.g., using transmission component 704, depicted in FIG. 7) may transmit, to the base station, a sequence indicating that a HARQ-ACK feedback associated with the plurality of downlink shared channel transmissions includes only ACK bits for the plurality of downlink shared channel transmissions, as described above.
Process 500 may include additional aspects, such as any single aspect or any combination of aspects described below and/or in connection with one or more other processes described elsewhere herein.
In a first aspect, the sequence represents one bit.
In a second aspect, alone or in combination with the first aspect, the plurality of downlink shared channel transmissions are associated with ultra-reliable low latency communications.
In a third aspect, alone or in combination with one or more of the first and second aspects, transmitting the sequence includes transmitting the sequence using an uplink control channel resource via an uplink control channel.
In a fourth aspect, alone or in combination with one or more of the first through third aspects, the uplink control channel resource is not configured to carry additional uplink control information bits.
In a fifth aspect, alone or in combination with one or more of the first through fourth aspects, the uplink control channel resource is not configured to carry a channel state information report.
In a sixth aspect, alone or in combination with one or more of the first through fifth aspects, the uplink control channel resource is not configured to carry a scheduling request.
In a seventh aspect, alone or in combination with one or more of the first through sixth aspects, a symbol length associated with the uplink control channel resource carrying the sequence is less than a symbol length associated with an uplink control channel resource carrying a plurality of ACK bits.
Although FIG. 5 shows example blocks of process 500, in some aspects, process 500 may include additional blocks, fewer blocks, different blocks, or differently arranged blocks than those depicted in FIG. 5. Additionally, or alternatively, two or more of the blocks of process 500 may be performed in parallel.
FIG. 6 is a diagram illustrating an example process 600 performed, for example, by a base station, in accordance with various aspects of the present disclosure. Example process 600 is an example where the base station (e.g., base station 110) performs operations associated with sequence-based HARQ-ACK feedback.
As shown in FIG. 6, in some aspects, process 600 may include transmitting, to a UE, a plurality of downlink shared channel transmissions (block 610). For example, the base station (e.g., using transmission component 804, depicted in FIG. 8) may transmit, to a UE, a plurality of downlink shared channel transmissions, as described above.
As further shown in FIG. 6, in some aspects, process 600 may include receiving, from the UE, a sequence indicating that a HARQ-ACK feedback associated with the plurality of downlink shared channel transmissions includes only ACK bits for the plurality of downlink shared channel transmissions (block 620). For example, the base station (e.g., using reception component 802, depicted in FIG. 8) may receive, from the UE, a sequence indicating that a HARQ-ACK feedback associated with the plurality of downlink shared channel transmissions includes only ACK bits for the plurality of downlink shared channel transmissions, as described above.
Process 600 may include additional aspects, such as any single aspect or any combination of aspects described below and/or in connection with one or more other processes described elsewhere herein.
In a first aspect, the sequence represents one bit.
In a second aspect, alone or in combination with the first aspect, receiving the sequence includes receiving the sequence via an uplink control channel using an uplink control channel resource.
In a third aspect, alone or in combination with one or more of the first and second aspects, the uplink control channel resource is not configured to carry additional uplink control information bits.
In a fourth aspect, alone or in combination with one or more of the first through third aspects, the uplink control channel resource is not configured to carry a channel state information report.
In a fifth aspect, alone or in combination with one or more of the first through fourth aspects, the uplink control channel resource is not configured to carry a scheduling request.
In a sixth aspect, alone or in combination with one or more of the first through fifth aspects, a symbol length associated with the uplink control channel resource carrying the sequence is less than a symbol length associated with an uplink control channel resource carrying a plurality of ACK bits.
Although FIG. 6 shows example blocks of process 600, in some aspects, process 600 may include additional blocks, fewer blocks, different blocks, or differently arranged blocks than those depicted in FIG. 6. Additionally, or alternatively, two or more of the blocks of process 600 may be performed in parallel.
FIG. 7 is a block diagram of an example apparatus 700 for wireless communication. The apparatus 700 may be a UE, or a UE may include the apparatus 700. In some aspects, the apparatus 700 includes a reception component 702 and a transmission component 704, which may be in communication with one another (for example, via one or more buses and/or one or more other components). As shown, the apparatus 700 may communicate with another apparatus 706 (such as a UE, a base station, or another wireless communication device) using the reception component 702 and the transmission component 704.
In some aspects, the apparatus 700 may be configured to perform one or more operations described herein in connection with FIG. 4. Additionally, or alternatively, the apparatus 700 may be configured to perform one or more processes described herein, such as process 500 of FIG. 5. In some aspects, the apparatus 700 and/or one or more components shown in FIG. 7 may include one or more components of the UE described above in connection with FIG. 2. Additionally, or alternatively, one or more components shown in FIG. 7 may be implemented within one or more components described above in connection with FIG. 2. Additionally, or alternatively, one or more components of the set of components may be implemented at least in part as software stored in a memory. For example, a component (or a portion of a component) may be implemented as instructions or code stored in a non-transitory computer-readable medium and executable by a controller or a processor to perform the functions or operations of the component.
The reception component 702 may receive communications, such as reference signals, control information, data communications, or a combination thereof, from the apparatus 706. The reception component 702 may provide received communications to one or more other components of the apparatus 700. In some aspects, the reception component 702 may perform signal processing on the received communications (such as filtering, amplification, demodulation, analog-to-digital conversion, demultiplexing, deinterleaving, de-mapping, equalization, interference cancellation, or decoding, among other examples), and may provide the processed signals to the one or more other components of the apparatus 706. In some aspects, the reception component 702 may include one or more antennas, a demodulator, a MIMO detector, a receive processor, a controller/processor, a memory, or a combination thereof, of the UE described above in connection with FIG. 2.
The transmission component 704 may transmit communications, such as reference signals, control information, data communications, or a combination thereof, to the apparatus 706. In some aspects, one or more other components of the apparatus 706 may generate communications and may provide the generated communications to the transmission component 704 for transmission to the apparatus 706. In some aspects, the transmission component 704 may perform signal processing on the generated communications (such as filtering, amplification, modulation, digital-to-analog conversion, multiplexing, interleaving, mapping, or encoding, among other examples), and may transmit the processed signals to the apparatus 706. In some aspects, the transmission component 704 may include one or more antennas, a modulator, a transmit MIMO processor, a transmit processor, a controller/processor, a memory, or a combination thereof, of the UE described above in connection with FIG. 2. In some aspects, the transmission component 704 may be co-located with the reception component 702 in a transceiver.
The reception component 702 may receive, from a base station, a plurality of downlink shared channel transmissions. The transmission component 704 may transmit, to the base station, a sequence indicating that a HARQ-ACK feedback associated with the plurality of downlink shared channel transmissions includes only ACK bits for the plurality of downlink shared channel transmissions.
The transmission component 704 may transmit the sequence using an uplink control channel resource via an uplink control channel.
The number and arrangement of components shown in FIG. 7 are provided as an example. In practice, there may be additional components, fewer components, different components, or differently arranged components than those shown in FIG. 7. Furthermore, two or more components shown in FIG. 7 may be implemented within a single component, or a single component shown in FIG. 7 may be implemented as multiple, distributed components. Additionally, or alternatively, a set of (one or more) components shown in FIG. 7 may perform one or more functions described as being performed by another set of components shown in FIG. 7.
FIG. 8 is a block diagram of an example apparatus 800 for wireless communication. The apparatus 800 may be a base station, or a base station may include the apparatus 800. In some aspects, the apparatus 800 includes a reception component 802 and a transmission component 804, which may be in communication with one another (for example, via one or more buses and/or one or more other components). As shown, the apparatus 800 may communicate with another apparatus 806 (such as a UE, a base station, or another wireless communication device) using the reception component 802 and the transmission component 804.
In some aspects, the apparatus 800 may be configured to perform one or more operations described herein in connection with FIG. 4. Additionally, or alternatively, the apparatus 800 may be configured to perform one or more processes described herein, such as process 600 of FIG. 6. In some aspects, the apparatus 800 and/or one or more components shown in FIG. 8 may include one or more components of the base station described above in connection with FIG. 2. Additionally, or alternatively, one or more components shown in FIG. 8 may be implemented within one or more components described above in connection with FIG. 2. Additionally, or alternatively, one or more components of the set of components may be implemented at least in part as software stored in a memory. For example, a component (or a portion of a component) may be implemented as instructions or code stored in a non-transitory computer-readable medium and executable by a controller or a processor to perform the functions or operations of the component.
The reception component 802 may receive communications, such as reference signals, control information, data communications, or a combination thereof, from the apparatus 806. The reception component 802 may provide received communications to one or more other components of the apparatus 800. In some aspects, the reception component 802 may perform signal processing on the received communications (such as filtering, amplification, demodulation, analog-to-digital conversion, demultiplexing, deinterleaving, de-mapping, equalization, interference cancellation, or decoding, among other examples), and may provide the processed signals to the one or more other components of the apparatus 806. In some aspects, the reception component 802 may include one or more antennas, a demodulator, a MIMO detector, a receive processor, a controller/processor, a memory, or a combination thereof, of the base station described above in connection with FIG. 2.
The transmission component 804 may transmit communications, such as reference signals, control information, data communications, or a combination thereof, to the apparatus 806. In some aspects, one or more other components of the apparatus 806 may generate communications and may provide the generated communications to the transmission component 804 for transmission to the apparatus 806. In some aspects, the transmission component 804 may perform signal processing on the generated communications (such as filtering, amplification, modulation, digital-to-analog conversion, multiplexing, interleaving, mapping, or encoding, among other examples), and may transmit the processed signals to the apparatus 806. In some aspects, the transmission component 804 may include one or more antennas, a modulator, a transmit MIMO processor, a transmit processor, a controller/processor, a memory, or a combination thereof, of the base station described above in connection with FIG. 2. In some aspects, the transmission component 804 may be co-located with the reception component 802 in a transceiver.
The transmission component 804 may transmit, to a UE, a plurality of downlink shared channel transmissions. The reception component 802 may receive, from the UE, a sequence indicating that a HARQ-ACK feedback associated with the plurality of downlink shared channel transmissions includes only ACK bits for the plurality of downlink shared channel transmissions.
The reception component 802 may receive the sequence via an uplink control channel using an uplink control channel resource.
The number and arrangement of components shown in FIG. 8 are provided as an example. In practice, there may be additional components, fewer components, different components, or differently arranged components than those shown in FIG. 8. Furthermore, two or more components shown in FIG. 8 may be implemented within a single component, or a single component shown in FIG. 8 may be implemented as multiple, distributed components. Additionally, or alternatively, a set of (one or more) components shown in FIG. 8 may perform one or more functions described as being performed by another set of components shown in FIG. 8.
The following provides an overview of aspects of the present disclosure:
Aspect 1: A method of wireless communication performed by a user equipment (UE), comprising: receiving, from a base station, a plurality of downlink shared channel transmissions; and transmitting, to the base station, a sequence indicating that a hybrid automatic repeat request (HARQ)-acknowledgement (ACK) feedback associated with the plurality of downlink shared channel transmissions includes only ACK bits for the plurality of downlink shared channel transmissions.
Aspect 2: The method of aspect 1, wherein the sequence represents one bit.
Aspect 3: The method of any of aspects 1 through 2, wherein the plurality of downlink shared channel transmissions are associated with ultra-reliable low latency communications.
Aspect 4: The method of any of aspects 1 through 3, wherein transmitting the sequence includes transmitting the sequence using an uplink control channel resource via an uplink control channel.
Aspect 5: The method of aspect 4, wherein the uplink control channel resource is not configured to carry additional uplink control information bits.
Aspect 6: The method of any of aspects 4 through 5, wherein the uplink control channel resource is not configured to carry a channel state information report.
Aspect 7: The method of any of aspects 4 through 6, wherein the uplink control channel resource is not configured to carry a scheduling request.
Aspect 8: The method of any of aspects 4 through 7, wherein a symbol length associated with the uplink control channel resource carrying the sequence is less than a symbol length associated with an uplink control channel resource carrying a plurality of ACK bits.
Aspect 9: A method of wireless communication performed by a base station, comprising: transmitting, to a user equipment (UE), a plurality of downlink shared channel transmissions; and receiving, from the UE, a sequence indicating that a hybrid automatic repeat request (HARQ)-acknowledgement (ACK) feedback associated with the plurality of downlink shared channel transmissions includes only ACK bits for the plurality of downlink shared channel transmissions.
Aspect 10: The method of aspect 9, wherein the sequence represents one bit.
Aspect 11: The method of any of aspects 9 through 10, wherein receiving the sequence includes receiving the sequence via an uplink control channel using an uplink control channel resource.
Aspect 12: The method of aspect 11, wherein the uplink control channel resource is not configured to carry additional uplink control information bits.
Aspect 13: The method of any of aspects 11 through 12, wherein the uplink control channel resource is not configured to carry a channel state information report.
Aspect 14: The method of any of aspects 11 through 13, wherein the uplink control channel resource is not configured to carry a scheduling request.
Aspect 15: The method of any of aspects 11 through 14, wherein a symbol length associated with the uplink control channel resource carrying the sequence is less than a symbol length associated with an uplink control channel resource carrying a plurality of ACK bits.
Aspect 16: An apparatus for wireless communication at a device, comprising a processor; memory coupled with the processor; and instructions stored in the memory and executable by the processor to cause the apparatus to perform the method of one or more aspects of aspects 1-15.
Aspect 17: A device for wireless communication, comprising a memory and one or more processors coupled to the memory, the memory and the one or more processors configured to perform the method of one or more aspects of aspects 1-15.
Aspect 18: An apparatus for wireless communication, comprising at least one means for performing the method of one or more aspects of aspects 1-15.
Aspect 19: A non-transitory computer-readable medium storing code for wireless communication, the code comprising instructions executable by a processor to perform the method of one or more aspects of aspects 1-15.
Aspect 20: A non-transitory computer-readable medium storing a set of instructions for wireless communication, the set of instructions comprising one or more instructions that, when executed by one or more processors of a device, cause the device to perform the method of one or more aspects of aspects 1-15.
The foregoing disclosure provides illustration and description, but is not intended to be exhaustive or to limit the aspects to the precise forms disclosed. Modifications and variations may be made in light of the above disclosure or may be acquired from practice of the aspects.
As used herein, the term “component” is intended to be broadly construed as hardware and/or a combination of hardware and software. “Software” shall be construed broadly to mean instructions, instruction sets, code, code segments, program code, programs, subprograms, software modules, applications, software applications, software packages, routines, subroutines, objects, executables, threads of execution, procedures, and/or functions, among other examples, whether referred to as software, firmware, middleware, microcode, hardware description language, or otherwise. As used herein, a processor is implemented in hardware and/or a combination of hardware and software. It will be apparent that systems and/or methods described herein may be implemented in different forms of hardware and/or a combination of hardware and software. The actual specialized control hardware or software code used to implement these systems and/or methods is not limiting of the aspects. Thus, the operation and behavior of the systems and/or methods were described herein without reference to specific software code—it being understood that software and hardware can be designed to implement the systems and/or methods based, at least in part, on the description herein.
As used herein, satisfying a threshold may, depending on the context, refer to a value being greater than the threshold, greater than or equal to the threshold, less than the threshold, less than or equal to the threshold, equal to the threshold, not equal to the threshold, or the like.
Even though particular combinations of features are recited in the claims and/or disclosed in the specification, these combinations are not intended to limit the disclosure of various aspects. In fact, many of these features may be combined in ways not specifically recited in the claims and/or disclosed in the specification. Although each dependent claim listed below may directly depend on only one claim, the disclosure of various aspects includes each dependent claim in combination with every other claim in the claim set. As used herein, a phrase referring to “at least one of” a list of items refers to any combination of those items, including single members. As an example, “at least one of: a, b, or c” is intended to cover a, b, c, a-b, a-c, b-c, and a-b-c, as well as any combination with multiples of the same element (e.g., a-a, a-a-a, a-a-b, a-a-c, a-b-b, a-c-c, b-b, b-b-b, b-b-c, c-c, and c-c-c or any other ordering of a, b, and c).
No element, act, or instruction used herein should be construed as critical or essential unless explicitly described as such. Also, as used herein, the articles “a” and “an” are intended to include one or more items and may be used interchangeably with “one or more.” Further, as used herein, the article “the” is intended to include one or more items referenced in connection with the article “the” and may be used interchangeably with “the one or more.” Furthermore, as used herein, the terms “set” and “group” are intended to include one or more items (e.g., related items, unrelated items, or a combination of related and unrelated items), and may be used interchangeably with “one or more.” Where only one item is intended, the phrase “only one” or similar language is used. Also, as used herein, the terms “has,” “have,” “having,” or the like are intended to be open-ended terms. Further, the phrase “based on” is intended to mean “based, at least in part, on” unless explicitly stated otherwise. Also, as used herein, the term “or” is intended to be inclusive when used in a series and may be used interchangeably with “and/or,” unless explicitly stated otherwise (e.g., if used in combination with “either” or “only one of”).

## Claims

1. A method of wireless communication performed by a user equipment (UE), comprising:
receiving, from a network entity, a plurality of downlink shared channel transmissions; and
transmitting, to the network entity and using a first uplink control channel resource that is associated with a first symbol length, a sequence indicating that a hybrid automatic repeat request (HARQ)-acknowledgement (ACK) feedback associated with the plurality of downlink shared channel transmissions includes only ACK bits for the plurality of downlink shared channel transmissions, the sequence including a quantity of bits that is less than a plurality of ACK bits, each ACK bit of the plurality of ACK bits corresponding to a downlink shared channel transmission of the plurality of downlink shared channel transmissions, wherein the first symbol length is less than a second symbol length associated with a second uplink control channel resource carrying the plurality of ACK bits.

2. The method of claim 1, wherein the sequence represents one bit.

3. The method of claim 1, wherein the plurality of downlink shared channel transmissions are associated with ultra-reliable low latency communications.

4. The method of claim 1, wherein transmitting the sequence includes transmitting the sequence using an uplink control channel resource via an uplink control channel.

5. The method of claim 4, wherein the uplink control channel resource is not configured to carry additional uplink control information bits.

6. The method of claim 4, wherein the uplink control channel resource is not configured to carry a channel state information report.

7. The method of claim 4, wherein the uplink control channel resource is not configured to carry a scheduling request.

8. A method of wireless communication performed by a network entity, comprising:
transmitting, to a user equipment (UE), a plurality of downlink shared channel transmissions; and
receiving, from the UE and using a first uplink control channel resource that is associated with a first symbol length, a sequence indicating that a hybrid automatic repeat request (HARQ)-acknowledgement (ACK) feedback associated with the plurality of downlink shared channel transmissions includes only ACK bits for the plurality of downlink shared channel transmissions, the sequence including a quantity of bits that is less than a plurality of ACK bits, each ACK bit of the plurality of ACK bits corresponding to a downlink shared channel transmission of the plurality of downlink shared channel transmissions, wherein the first symbol length is less than a second symbol length associated with a second uplink control channel resource carrying the plurality of ACK bits.

9. The method of claim 8, wherein the sequence represents one bit.

10. The method of claim 8, wherein receiving the sequence includes receiving the sequence via an uplink control channel using an uplink control channel resource.

11. The method of claim 10, wherein the uplink control channel resource is not configured to carry additional uplink control information bits.

12. The method of claim 10, wherein the uplink control channel resource is not configured to carry a channel state information report.

13. The method of claim 10, wherein the uplink control channel resource is not configured to carry a scheduling request.

14. The method of claim 8, wherein the plurality of downlink shared channel transmissions are associated with ultra-reliable low latency communications.

15. An apparatus for wireless communication, comprising:
a memory; and
one or more processors coupled to the memory, wherein the apparatus is configured to:
receive, from a network entity, a plurality of downlink shared channel transmissions; and
transmit, to the network entity and using a first uplink control channel resource that is associated with a first symbol length, a sequence indicating that a hybrid automatic repeat request (HARQ)-acknowledgement (ACK) feedback associated with the plurality of downlink shared channel transmissions includes only ACK bits for the plurality of downlink shared channel transmissions, the sequence including a quantity of bits that is less than a plurality of ACK bits, each ACK bit of the plurality of ACK bits corresponding to a downlink shared channel transmission of the plurality of downlink shared channel transmissions, wherein the first symbol length is less than a second symbol length associated with a second uplink control channel resource carrying the plurality of ACK bits.

16. The apparatus of claim 15, wherein the sequence represents one bit.

17. The apparatus of claim 15, wherein the plurality of downlink shared channel transmissions are associated with ultra-reliable low latency communications.

18. The apparatus of claim 15, wherein, to transmit the sequence, the apparatus is configured to transmit the sequence using an uplink control channel resource via an uplink control channel.

19. The apparatus of claim 18, wherein the uplink control channel resource is not configured to carry additional uplink control information bits.

20. The apparatus of claim 18, wherein the uplink control channel resource is not configured to carry a channel state information report.

21. The apparatus of claim 18, wherein the uplink control channel resource is not configured to carry a scheduling request.

22. An apparatus for wireless communication, comprising:
a memory; and
one or more processors coupled to the memory, wherein the one or more processors apparatus is configured to:
transmit, to a user equipment (UE), a plurality of downlink shared channel transmissions; and
receive, from the UE and using a first uplink control channel resource that is associated with a first symbol length, a sequence indicating that a hybrid automatic repeat request (HARQ)-acknowledgement (ACK) feedback associated with the plurality of downlink shared channel transmissions includes only ACK bits for the plurality of downlink shared channel transmissions, the sequence including a quantity of bits that is less than a plurality of ACK bits, each ACK bit of the plurality of ACK bits corresponding to a downlink shared channel transmission of the plurality of downlink shared channel transmissions, wherein the first symbol length is less than a second symbol length associated with a second uplink control channel resource carrying the plurality of ACK bits.

23. The apparatus of claim 22, wherein the sequence represents one bit.

24. The apparatus of claim 22, wherein, to receive the sequence, the apparatus is configured to receive the sequence via an uplink control channel using an uplink control channel resource.

25. The apparatus of claim 24, wherein the uplink control channel resource is not configured to carry additional uplink control information bits.

26. The apparatus of claim 24, wherein the uplink control channel resource is not configured to carry a channel state information report.

27. The apparatus of claim 24, wherein the uplink control channel resource is not configured to carry a scheduling request.

28. The apparatus of claim 22, wherein the plurality of downlink shared channel transmissions are associated with ultra-reliable low latency communications.