WO2022061792A1

WO2022061792A1 - Storage-free harq process

Info

Publication number: WO2022061792A1
Application number: PCT/CN2020/117984
Authority: WO
Inventors: Min Huang; Chao Wei; Chenxi HAO; Qiaoyu Li; Jing Dai; Wei XI; Liangming WU; Kangqi LIU; Hao Xu; Wanshi Chen
Original assignee: Qualcomm Incorporated
Priority date: 2020-09-27
Filing date: 2020-09-27
Publication date: 2022-03-31

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 configuration of one or more storage-free hybrid automatic repeat request (HARQ) processes for which the UE is not required to store decoding error soft bits. The UE may communicate with the base station using the one or more storage-free HARQ processes. Numerous other aspects are provided.

Description

STORAGE-FREE HARQ PROCESS

FIELD OF THE DISCLOSURE

Aspects of the present disclosure generally relate to wireless communication and to techniques and apparatuses for a storage-free hybrid automatic repeat request (HARQ) process.

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, and/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, and/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 configuration of one or more storage-free hybrid automatic repeat request (HARQ) processes for which the UE is not required to store decoding error soft bits; and communicating with the base station using the one or more storage-free HARQ processes.

In some aspects, a method of wireless communication performed by a base station includes transmitting, to a UE, a configuration of one or more storage-free HARQ processes for which the UE is not required to store decoding error soft bits; and communicating with the UE using the one or more storage-free HARQ processes.

In some aspects, a method of wireless communication performed by a UE includes determining to use a storage-free HARQ process for a downlink communication received from a base station; and transmitting, to the base station, HARQ feedback for the downlink communication based at least in part on the storage-free HARQ process.

In some aspects, a method of wireless communication performed by a base station includes transmitting, to a UE, an indication to use a storage-free HARQ process for a downlink communication transmitted to the UE; and receiving, from the UE, HARQ feedback for the downlink communication based at least in part on the storage-free HARQ process.

In some aspects, an apparatus for wireless communication includes means for receiving, from a base station, a configuration of one or more storage-free HARQ processes for which the apparatus is not required to store decoding error soft bits; and means for communicating with the base station using the one or more storage-free HARQ processes.

In some aspects, an apparatus for wireless communication includes means for transmitting, to a UE, a configuration of one or more storage-free HARQ processes for which the UE is not required to store decoding error soft bits; and means for communicating with the UE using the one or more storage-free HARQ processes.

In some aspects, an apparatus for wireless communication includes means for determining to use a storage-free HARQ process for a downlink communication received from a base station; and means for transmitting, to the base station, HARQ feedback for the downlink communication based at least in part on the storage-free HARQ process.

In some aspects, an apparatus for wireless communication includes means for transmitting, to a UE, an indication to use a storage-free HARQ process for a downlink communication transmitted to the UE; and means for receiving, from the UE, HARQ feedback for the downlink communication based at least in part on the storage-free HARQ process.

In some aspects, a UE for wireless communication includes memory, one or more processors coupled to the memory, and instructions stored in the memory and operable, when executed by the one or more processors, to cause the UE to: receive, from a base station, a configuration of one or more storage-free HARQ processes for which the UE is not required to store decoding error soft bits; and communicate with the base station using the one or more storage-free HARQ processes.

In some aspects, a base station for wireless communication includes memory, one or more processors coupled to the memory, and instructions stored in the memory and operable, when executed by the one or more processors, to cause the base station to: transmit, to a UE, a configuration of one or more storage-free HARQ processes for which the UE is not required to store decoding error soft bits; and communicate with the UE using the one or more storage-free HARQ processes.

In some aspects, a UE for wireless communication includes memory, one or more processors coupled to the memory, and instructions stored in the memory and operable, when executed by the one or more processors, to cause the UE to: determine to use a storage-free HARQ process for a downlink communication received from a base station; and transmit, to the base station, HARQ feedback for the downlink communication based at least in part on the storage-free HARQ process.

In some aspects, a base station for wireless communication includes memory, one or more processors coupled to the memory, and instructions stored in the memory and operable, when executed by the one or more processors, to cause the base station to: transmit, to a UE, an indication to use a storage-free HARQ process for a downlink communication transmitted to the UE; and receive, from the UE, HARQ feedback for the downlink communication based at least in part on the storage-free HARQ process.

In some aspects, a non-transitory computer-readable medium stores one or more instructions for wireless communication that, when executed by one or more processors of a UE, cause the UE to: receive, from a base station, a configuration of one or more storage-free HARQ processes for which the UE is not required to store decoding error soft bits; and communicate with the base station using the one or more storage-free HARQ processes.

In some aspects, a non-transitory computer-readable medium stores one or more instructions for wireless communication that, when executed by one or more processors of a base station, cause the base station to: transmit, to a UE, a configuration of one or more storage-free HARQ processes for which the UE is not required to store decoding error soft bits; and communicate with the UE using the one or more storage-free HARQ processes.

In some aspects, a non-transitory computer-readable medium stores one or more instructions for wireless communication that, when executed by one or more processors of an UE, cause the UE to: determine to use a storage-free HARQ process for a downlink communication received from a base station; and transmit, to the base station, HARQ feedback for the downlink communication based at least in part on the storage-free HARQ process.

In some aspects, a non-transitory computer-readable medium stores one or more instructions for wireless communication that, when executed by one or more processors of a base station, cause the base station to: transmit, to a UE, an indication to use a storage-free HARQ process for a downlink communication transmitted to the UE; and receive, from the UE, HARQ feedback for the downlink communication based at least in part on the storage-free HARQ process.

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.

Figs. 3A, 3B, 4A, and 4B are diagrams illustrating examples associated with a storage-free hybrid automatic repeat request (HARQ) process, in accordance with various aspects of the present disclosure.

Figs. 5-8 are diagrams illustrating example processes associated with a storage-free HARQ process, in accordance with various aspects of the present disclosure.

Figs. 9-12 are block diagrams of example apparatuses for wireless communication, in accordance with various aspects of the present disclosure.

DETAILED DESCRIPTION

In some cases, a base station may serve user equipments (UEs) of different categories and/or may serve UEs that support different capabilities. For example, the base station may serve a first category of UEs that have a less advanced capability (e.g., a lower capability and/or a reduced capability) and a second category of UEs that have a more advanced capability (e.g., a higher capability) . A UE of the first category may have a reduced feature set compared to UEs of the second category, and may be referred to as a reduced capability (RedCap) UE, a low tier UE, and/or a New Radio (NR) -Lite UE, among other examples. A UE of the first category may be, for example, a machine-type communication (MTC) UE, an evolved or enhanced MTC (eMTC) UE, and/or an Internet of things (IoT) UE, among other examples. A UE of the second category may have an advanced feature set compared to UEs of the second category, and may be referred to as a baseline UE, a high tier UE, an NR UE, and/or a premium UE, among other examples. For example, UEs of the first category may support a lower maximum modulation and coding scheme (MCS) than UEs of the second category (e.g., quadrature phase shift keying (QPSK) or the like as compared to 256-quadrature amplitude modulation (QAM) or the like) , may support a lower maximum transmit power than UEs of the second category, may have a less advanced beamforming capability than UEs of the second category (e.g., may not be capable of forming as many beams as UEs of the second category) , may require a longer processing time than UEs of the second category, may include less hardware than UEs of the second category (e.g., fewer antennas, fewer transmit antennas, and/or fewer receive antennas) , and/or may not be capable of communicating on as wide of a maximum bandwidth part as UEs of the second category, among other examples.

In some cases, a UE of the first category may be capable of storing fewer hybrid automatic repeat request (HARQ) soft bits relative to a UE of the second category. As a result, a UE of the first category may support fewer HARQ processes relative to a UE of the second category because a UE is typically configured or required to store soft bits for each HARQ process. For example, a RedCap UE or NR-Lite UE may be capable of supporting up to 4 HARQ processes, whereas an NR UE or premium UE may be capable of supporting up to 6 HARQ processes. HARQ soft bits may be used to store information associated with a HARQ process, such as decoding error information, information about the logarithm likelihood ratio (LLR) value of a bit, information about the most likely value of a bit, a measure of the reliability or confidence of the LLR value or most likely value, and/or other types of information. The term "soft information" or "soft bit" generally refers to not making a hard decision about the value of a bit during demodulation and/or input to a decoder. These measures of reliability can be used in special soft decision decoders (e.g., Turbo decoders or LDPC decoders) to enhance decoding performance. For example, a decoded received packet and its supporting data (e.g., the soft bits) are generally stored in soft buffer memory to accommodate combining the data with retransmitted data in the event that a determination is made that the communication was received in error for a previous transmission or previous retransmission. In a HARQ scheme, the receiver may request retransmission of a communication (or part of the communication) , if the communication is not received correctly. At the receiver, the retransmitted communication may be combined with the originally received communication and the associated soft bits before decoding.

A base station may configure a cell of the base station such that UEs in the cell, regardless of whether they are first category UEs or second category UEs, are to activate a particular quantity of HARQ processes. The HARQ processes may be used for unicast traffic (e.g., traffic between the base station and a single UE) and multicast traffic (e.g., traffic between the base station and a plurality of UEs) . For first category UEs, supporting unicast traffic and multicast traffic with fewer HARQ processes relative to second category UEs may result in HARQ process exhaustion. “HARQ process exhaustion” may refer to a scenario in which a UE has a transmission to receive (e.g., a transmission of unicast traffic or multicast traffic) but does not have an available HARQ process to use to process the transmission (e.g., because all of the UE’s HARQ processes are being used to process other transmissions) . As a result, the UE is unable to receive the transmission until a HARQ process is made available for use in processing the transmission (which can occur, for example, where another transmission being processed is decoded successfully or a threshold quantity of retransmission attempts are reached for the other transmission) . This can cause delays in receiving the transmission, can increase the quantity of retransmissions for the transmission, can result in the transmission being dropped by the UE, and/or can cause other transmissions to be delayed. This can increase latency for the UE, decrease throughput for the UE, and/or decrease reliability for the UE.

Some aspects described herein provide techniques and apparatuses for a storage-free HARQ process. A UE may be configured to use and/or implement a storage-free HARQ process (which may also be referred to as a HARQ without retransmission or a HARQ process for which a new data indicator (NDI) value of 1 is expected in the downlink control information (DCI) scheduling a transmission associated with the HARQ process) . The storage-free HARQ process may be a HARQ process for which the UE is not configured or not required to store the associated soft bits. Storage-free HARQ processes may enable a UE (and particularly RedCap UEs and/or NR-lite UEs) to support a greater quantity of HARQ processes without increasing the UE’s soft bit storage capability (and thus, the complexity of the UE) .

In this way, the UE may be capable of using a storage-free HARQ process to receive and process a transmission even if the UE does not have any soft bits available for storing decoding information associated with the transmission. The UE can be configured to use and/or implement only storage-free HARQ processes, or a combination of storage-required (or legacy) HARQ processes and storage-free HARQ processes, to enable the UE to use retransmissions to increase communication reliability and robustness while decreasing latency and increasing throughput. The UE can be configured (e.g., by a base station) to use a storage-required HARQ process or a storage-free HARQ process for a particular transmission, or a UE can be permitted to choose which type of HARQ process to use for a particular communication, which increases the HARQ process flexibility of the UE.

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, and/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, an LTE network, and/or the like. 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 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) , and/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) ) . A BS for a macro cell may be referred to as a macro BS. A BS 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, a virtual network, and/or the like 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, and/or the like.

Wireless network 100 may be a heterogeneous network that includes BSs of different types, e.g., macro BSs, pico BSs, femto BSs, relay BSs, and/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, e.g., 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, and/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.

A UE 120 may be configured to provide feedback for downlink communications received from a base station 110. For example, a UE 120 may transmit an acknowledgment (ACK) communication for a downlink communication that the UE 120 was able to successfully demodulate and decode, and may transmit a NACK communication for a downlink communication to indicate that a demodulation and decoding attempt was unsuccessful. A UE 120 may use a plurality of HARQ processes to provide feedback to a base station 110. Each HARQ process may implement a stop and wait procedure, in which the UE 120 stops and waits for a downlink communication to be successfully received before receiving the next downlink communication in the HARQ process. A HARQ process may include a HARQ buffer (or soft buffer) in which soft bits associated with decoding errors are stored. These soft bits may be used for HARQ combining with retransmissions to increase reliability and to increase the effectiveness of HARQ retransmissions.

Some UEs may be considered RedCap UEs, NR-lite UEs, MTC UEs, eMTC UEs, or IoT UEs. MTC and eMTC UEs include, for example, robots, drones, remote devices, sensors, meters, monitors, location tags, and/or the like, 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. IoT UEs may be considered 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, memory components, and/or the like. 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, electrically coupled, and/or the like.

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, and/or the like. A frequency may also be referred to as a carrier, a frequency channel, and/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, a vehicle-to-infrastructure (V2I) protocol, and/or the like) , a mesh network, and/or the like. 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, and/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/or the like) and control information (e.g., CQI requests, grants, upper layer signaling, and/or the like) 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) , a demodulation reference signal (DMRS) , and/or the like) and synchronization signals (e.g., the primary synchronization signal (PSS) and 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 and/or the like) 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 and/or the like) 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 reference signal received power (RSRP) , received signal strength indicator (RSSI) , reference signal received quality (RSRQ) , channel quality indicator (CQI) , and/or the like. 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, CQI, and/or the like) 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, CP-OFDM, and/or the like) , and transmitted to base station 110. 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. 3A-8.

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, 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. 3A-8.

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 a storage-free HARQ process, 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, process 700 of Fig. 7, process 800 of Fig. 8, 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, program code, and/or the like) for wireless communication. For example, the one or more instructions, when executed (e.g., directly, or after compiling, converting, interpreting, and/or the like) 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, process 700 of Fig. 7, process 800 of Fig. 8, and/or other processes as described herein. In some aspects, executing instructions may include running the instructions, converting the instructions, compiling the instructions, interpreting the instructions, and/or the like.

In some aspects, a UE 120 includes means for receiving, from a base station 110, a configuration of one or more storage-free HARQ processes for which the UE is not required to store decoding error soft bits, and/or means for communicating with the base station 110 using the one or more storage-free HARQ processes. In some aspects, the UE 120 includes means for transmitting, to the base station 110, an indication of a UE capability for processing a quantity of storage-free HARQ processes. In some aspects, the UE 120 includes means for receiving, from the base station 110, a configuration of one or more storage-required HARQ processes for which the UE 120 is required to store decoding error soft bits, and/or means for communicating with the base station 110 using the one or more storage-required HARQ processes. The means for the UE 120 to perform operations described herein may include, for example, antenna 252, demodulator 254, MIMO detector 256, receive processor 258, transmit processor 264, TX MIMO processor 266, modulator 254, controller/processor 280, and/or memory 282.

In some aspects, a base station 110 includes means for transmitting, to a UE 120, a configuration of one or more storage-free HARQ processes for which the UE 120 is not required to store decoding error soft bits, and/or means for communicating with the UE 120 using the one or more storage-free HARQ processes. In some aspects, the base station 110 includes means for receiving, from the UE 120, an indication of a UE capability for processing a quantity of storage-free HARQ processes, and/or means for configuring a quantity of the one or more storage-free HARQ processes based at least in part on the UE capability. In some aspects, the base station 110 includes means for transmitting, to the UE 120, a configuration of one or more storage-required HARQ processes for which the UE 120 is required to store decoding error soft bits, and/or means for communicating with the UE 120 using the one or more storage-required HARQ processes. The means for the base station to perform operations described herein may include, for example, transmit processor 220, TX MIMO processor 230, modulator 232, antenna 234, demodulator 232, MIMO detector 236, receive processor 238, controller/processor 240, memory 242, and/or scheduler 246.

In some aspects, a UE 120 includes means for determining to use a storage-free HARQ process for a downlink communication received from a base station 110 and/or means for transmitting, to the base station 110, HARQ feedback for the downlink communication based at least in part on the storage-free HARQ process. In some aspects, the UE 120 includes means for determining a decoding error for the downlink communication, and/or means for refraining from storing soft bits for the decoding error based at least in part on determining to use the storage-free HARQ process. In some aspects, the UE 120 includes means for determining to use the storage-free HARQ process based at least in part on receiving, from the base station 110, an indication to use the storage-free HARQ process for the downlink communication. In some aspects, the UE 120 includes means for transmitting a legacy negative acknowledgement (NACK) for the downlink communication based at least in part on receiving the indication to use the storage-free HARQ process for the downlink communication.

In some aspects, the UE 120 includes means for determining to use the storage-free HARQ process based at least in part on at least one of a determination that no storage-required HARQ processes for the UE 120 are available, a priority associated with the downlink communication, or a communication type associated with the downlink communication. In some aspects, the UE 120 includes means for transmitting a NACK specific to storage-free HARQ based at least in part on determining to use the storage-free HARQ process for the downlink communication, wherein the NACK specific to storage-free HARQ indicates that the UE 120 used the storage-free HARQ process for the downlink communication.

In some aspects, the UE 120 includes means for receiving, from the base station, a retransmission of the downlink communication based at least in part on the HARQ feedback, wherein a redundancy version (RV) for the retransmission is a same RV as an RV for an initial transmission of the downlink communication. In some aspects, the UE includes means for receiving, from the base station, a retransmission of the downlink communication based at least in part on the HARQ feedback, and/or means for receiving, from the base station, an indication to use a storage-required HARQ process for the retransmission. The means for the UE to perform operations described herein may include, for example, antenna 252, demodulator 254, MIMO detector 256, receive processor 258, transmit processor 264, TX MIMO processor 266, modulator 254, controller/processor 280, and/or memory 282.

In some aspects, a base station 110 includes means for transmitting, to a UE 120, an indication to use a storage-free HARQ process for a downlink communication transmitted to the UE 120, and/or means for receiving, from the UE 120, HARQ feedback for the downlink communication based at least in part on the storage-free HARQ process. In some aspects, the base station 110 includes means for receiving a legacy NACK for the downlink communication based at least in part on transmitting the indication to use the storage-free HARQ process for the downlink communication. In some aspects, the base station 110 includes means for transmitting the indication to use the storage-free HARQ process based at least in part on at least one of a determination that no storage-required HARQ processes for the UE 120 are available, a priority associated with the downlink communication, or a communication type associated with the downlink communication.

In some aspects, the base station 110 includes means for transmitting, to the UE 120, a retransmission of the downlink communication based at least in part on the HARQ feedback, wherein an RV for the retransmission is a same RV as an RV for an initial transmission of the downlink communication. In some aspects, the base station includes means for transmitting, to the UE 120, a retransmission of the downlink communication based at least in part on the HARQ feedback, and/or means for transmitting, to the UE 120, an indication to use a storage-required HARQ process for the retransmission. The means for the base station to perform operations described herein may include, for example, transmit processor 220, TX MIMO processor 230, modulator 232, antenna 234, demodulator 232, MIMO detector 236, receive processor 238, controller/processor 240, memory 242, and/or scheduler 246.

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.

Figs. 3A and 3B are diagrams illustrating one or more examples 300 associated with a storage-free HARQ process, in accordance with various aspects of the present disclosure. As shown in Figs. 3A and 3B, example (s) 300 include communication between a base station 110 and a UE 120. In some aspects, the base station 110 and the UE 120 may be included in a wireless network, such as the wireless network 100. The base station 110 and the UE 120 may communicate on a wireless access link, which may include an uplink and a downlink. In some aspects, the UE 120 is a reduced capability (RedCap) UE or an NR-lite UE with a reduced capability to store decoding error soft bits for HARQ processes associated with the UE 120.

The UE 120 is capable of configuring, implementing, and/or using one or more storage-free HARQ processes for which the UE 120 is not required to store decoding error soft bits. The UE 120 may be capable of configuring, implementing, and/or using the one or more storage-free HARQ processes with or without additional storage-required (or legacy) HARQ processes that required the UE 120 to store associated decoding error soft bits.

As shown in Fig. 3A, and by reference number 302, the UE 120 may transmit an indication of a UE capability for processing a particular quantity of storage-free HARQ processes. The UE 120 may transmit the indication to the base station 110, which may be a serving base station for the UE 120 or another base station. The UE 120 may determine the quantity of storage-free HARQ processes based at least in part on various attributes of the UE 120, such as the processing capability of the UE 120, the memory capability of the UE 120, and/or a quantity of storage-required HARQ processes that the UE 120 is to operate and/or activate, among other examples. The UE 120 may transmit the indication to the base station 110 in an uplink communication, such as a radio resource control (RRC) communication, a medium access control (MAC) control element (MAC-CE) communication, or an uplink control information (UCI) communication.

As further shown in Fig. 3A, and by reference number 304, the base station 110 may receive the indication and may configure one or more storage-free HARQ processes for the UE 120 based at least in part on the indication. Configuring the one or more storage-free HARQ processes may include configuring or generating a configuration (e.g., a HARQ configuration) for the UE 120. In some aspects, the base station configures the same quantity of storage-free HARQ processes for the UE 120 as the quantity of storage-free HARQ processes indicated by the UE capability. In some aspects, the base station configures fewer storage-free HARQ processes for the UE 120 than the quantity of storage-free HARQ processes indicated by the UE capability.

As further shown in Fig. 3A, and by reference number 306, the base station 110 may transmit the configuration (e.g., the HARQ configuration) of the one or more storage-free HARQ processes to the UE 120. The configuration may indicate the quantity of storage-free HARQ processes that the UE 120 is to use for communicating with the base station 110. The base station 110 may transmit the configuration to the UE 120 in a downlink communication, such as an RRC communication, a MAC-CE communication, a DCI communication, or another type of downlink communication.

In some aspects, the base station 110 may configure one or more storage-required HARQ processes for the UE 120, in addition to the one or more storage-free HARQ processes. In these examples, the configuration may further indicate a quantity of storage-required HARQ processes that the UE 120 is to use for communicating with the base station 110, in addition to the quantity of storage-free HARQ processes. In this way, the UE 120 is permitted to use a combination of storage-free HARQ processes and storage-required HARQ processes for communicating with the base station 110.

As shown in Fig. 3B, and by reference number 308, the base station 110 and the UE 120 may communicate using the one or more storage-free HARQ processes. The base station 110 and the UE 120 may be permitted to use (and may use) the one or more storage-free HARQ processes for unicast communication and/or multicast communication. In some aspects, the base station 110 and the UE 120 may further communicate using the one or more storage-required HARQ processes, in addition to using the one or more storage-free HARQ processes.

Communicating using a storage-free HARQ process may include the base station 110 transmitting a downlink communication to the UE 120, where the downlink communication is associated with the storage-free HARQ process. The UE 120 may attempt to demodulate and decode the downlink communication, and may refrain from storing decoding error soft bits for the downlink communication if the attempt to demodulate and decode the downlink communication is unsuccessful. Moreover, the UE 120 may transmit HARQ feedback to the base station 110, where the HARQ feedback is associated with the storage-free HARQ process. The HARQ feedback may include a NACK for the downlink communication.

As indicated above, Figs. 3A and 3B are provided as one or more examples. Other examples may differ from what is described with respect to Figs. 3A and 3B.

Figs. 4A and 4B are diagrams illustrating one or more examples 400 associated with a storage-free HARQ process, in accordance with various aspects of the present disclosure. As shown in Figs. 4A and 4B, example (s) 400 include communication between a base station 110 and a UE 120. In some aspects, the base station 110 and the UE 120 may be included in a wireless network, such as the wireless network 100. The base station 110 and the UE 120 may communicate on a wireless access link, which may include an uplink and a downlink. In some aspects, the UE 120 is a RedCap UE or an NR-lite UE with a reduced capability to store decoding error soft bits for HARQ processes associated with the UE 120.

As shown in Fig. 4A, the base station 110 may configure the UE 120 to activate, implement, and/or use a combination of one or more storage-required HARQ processes and one or more storage-free HARQ processes. For example, the base station 110 may configure the UE 120 to activate, implement, and/or use 4 storage-required HARQ processes (e.g., process 1 through process 4) and 2 storage-free HARQ processes (e.g., process 1 and process 2) . In some aspects, the base station 110 may transmit a configuration (e.g., a HARQ configuration) to the UE 120 to configure the one or more storage-required HARQ processes and the one or more storage-free HARQ processes, as described above in connection with Figs. 3A and 3B.

As further shown in Fig. 4A, the base station 110 may transmit a downlink communication to the UE 120. The downlink communication may include a unicast communication directed to the UE 120 or a multicast communication directed to the UE 120 and one or more other UEs. As shown by reference number 402, the base station 110, in some cases, may transmit an indication to the UE 120 to use a storage-free HARQ process for the downlink communication. The base station 110 may transmit the indication in a scheduling communication associated with the downlink communication, which may be included in an RRC communication, a MAC-CE communication, a DCI communication, or another type of downlink communication.

In some aspects, the indication to use a storage-free HARQ process for the downlink communication includes an explicit indication. In these examples, the base station 110 may configure a field in the scheduling communication. The field may be a field that is specifically configured to indicate whether the UE 120 is to use a storage-free HARQ process. A first value in the field may indicate that the UE 120 is to use a storage-free HARQ process for the associated downlink communication, and a second value in the field may indicate that the UE 120 is to not use a storage-free HARQ process and/or is use a storage-required HARQ process for the associated downlink communication.

In some aspects, the indication to use a storage-free HARQ process for the downlink communication includes an implicit indication. Such an implicit indication may include an indication of a HARQ process identifier associated with the downlink communication. In these examples, the one or more storage-required HARQ processes configured for the UE 120 may be associated with a first range of HARQ process identifiers, and the one or more storage-free HARQ processes may be associated with a second range of HARQ process identifiers that does not overlap with the first range of HARQ process identifiers. Accordingly, if the HARQ process identifier is included in the first range of HARQ process identifiers, a storage-required HARQ process is to be used for the downlink communication. Conversely, if the HARQ process identifier is included in the second range of HARQ process identifiers, a storage-free HARQ process is to be used for the downlink communication.

The base station 110 may transmit the indication to use a storage-free HARQ process for the downlink communication based at least in part on various factors. In some aspects, the base station 110 transmits the indication to use a storage-free HARQ process for the downlink communication based at least in part on determining that all of the storage-required HARQ processes of the UE 120 are in use, and therefore there are no storage-required HARQ processes for the UE 120 that are available to be used for the downlink communication. In some aspects, the base station 110 transmits the indication to use a storage-free HARQ process for the downlink communication based at least in part on a communication type associated with the downlink communication. For example, the base station 110 may transmit the indication to use a storage-free HARQ process for the downlink communication based at least in part on the downlink communication being a unicast communication or based at least in part on the downlink communication being a multicast communication.

In some aspects, the base station 110 transmits the indication to use a storage-free HARQ process for the downlink communication based at least in part on a priority associated with the downlink communication. In some cases, multicast traffic for the UE 120 may be higher priority than unicast traffic for the UE 120. In other cases, unicast traffic for the UE 120 is higher priority relative to multicast traffic for the UE 120. Examples of high-priority multicast traffic may include warning information, road map updates for a vehicle associated with the UE 120, instant data such as processing result sharing in multi-node coordinative calculation, interactive data such as status sharing in cooperation, and/or software upgrades. Examples of low-priority multicast traffic may include advertisements, news, and other types of content. In some cases, it may not be efficient or reasonable to permit the transmission of high-priority traffic from being blocked by low-priority traffic due to storage-required HARQ process exhaustion. Accordingly, the base station 110 may transmit the indication to use a storage-free HARQ process for high-priority traffic if no storage-required HARQ processes are available, or the base station 110 may transmit the indication to use a storage-free HARQ process for low-priority traffic if the base station 110 overwrites a storage-required HARQ process for the low-priority traffic such that the storage-required HARQ process can be used for high-priority traffic.

As shown in Fig. 4B, and by reference number 404, the UE 120 may determine to use a storage-free HARQ process for the downlink communication. In some aspects, the UE 120 determines to use a storage-free HARQ process based at least in part on receiving the indication from the base station 110 to use a storage-free HARQ process for the downlink communication. For example, the UE 120 may determine to use a storage-free HARQ process for the downlink communication based at least in part on an explicit indication in an associated scheduling communication to use a storage-free HARQ process. As another example, the UE 120 may determine to use a storage-free HARQ process for the downlink communication based at least in part on determining that the scheduling communication indicates a HARQ process identifier for the downlink communication that is included in a range of HARQ process identifiers configured for storage-free HARQ.

In some aspects, the base station 110 does not indicate whether to use a storage-free HARQ process or a storage-required HARQ process for the downlink communication. In these examples, the UE 120 may autonomously determine whether to use a storage-free HARQ process or a storage-required HARQ process for the downlink communication. The UE 120 may autonomously determine whether to use a storage-free HARQ process or a storage-required HARQ process for the downlink communication based at least in part on various factors, such as a determination that no storage-required HARQ processes for the UE 120 are available, a priority associated with the downlink communication, and/or a communication type associated with the downlink communication, as described above.

As an example, the base station 110 may configure the UE 120 to first use storage-required HARQ processes, and to use storage-free HARQ processes in cases where all of the storage-required HARQ processes are in use. As another example, the base station 110 may configure the UE 120 to use storage-required HARQ processes for high-priority traffic (e.g., high-priority multicast communications, high-priority unicast communications, downlink communications having a priority that satisfies a priority threshold) , and to use storage-free HARQ processes for low-priority traffic (e.g., low-priority multicast communications, low-priority unicast communications, downlink communications having a priority that does not satisfy a priority threshold) .

As further shown in Fig. 4B, and by reference number 406, the UE 120 may transmit HARQ feedback to the base station 110. The HARQ feedback may be based at least in part on an outcome or a result of a demodulation and decoding attempt for the downlink communication. For example, the HARQ feedback may include an ACK for a successful demodulation and decoding attempt, or may include a NACK for an unsuccessful demodulation and decoding attempt (e.g., for which a decoding error is determined) .

Moreover, the HARQ feedback may be based at least in part on the storage-free HARQ process, and whether or not the base station 110 indicated that the UE 120 was to use the storage-free HARQ process for the downlink communication. As an example, if the base station 110 indicated that the UE 120 was to use the storage-free HARQ process for the downlink communication, the UE 120 may transmit a legacy or common NACK for the downlink communication because the base station 110 already knows that the UE 120 used the storage-free HARQ process.

If the base station 110 did not indicate whether the UE 120 is to use a storage-free HARQ process for the downlink communication, the base station 110 may not know whether the UE 120 used a storage-free HARQ process or a storage required HARQ process for the downlink communication. Accordingly, the UE 120 may transmit a NACK that indicates that the UE 120 used the storage-free HARQ process for the downlink communication. The NACK may be a NACK that is specific to storage-free HARQ. For example, the NACK may be based at least in part on a particular NACK format for storage-free HARQ, may include an additional field or bit to indicate whether a storage-free HARQ process was used, and/or may indicate whether a storage-free HARQ process was used using another technique.

As further shown in Fig. 4B, and by reference number 408, the base station 110 may perform a retransmission of the downlink communication based at least in part on the HARQ feedback. For example, the base station 110 may perform the retransmission of the downlink communication based at least in part on receiving a NACK from the UE 120 for the downlink communication.

In some aspects, the base station 110 performs the retransmission of the downlink communication based at least in part on determining that the UE 120 used a storage-free HARQ process for the downlink communication. For example, the base station 110 may use the same RV for the retransmission as the RV for the initial transmission of the downlink communication, based at least in part on determining that the UE 120 used a storage-free HARQ process for the downlink communication. As another example, the base station 110 may use a different RV for the retransmission than the RV for the initial transmission of the downlink communication, based at least in part on determining that the UE 120 used a storage-free HARQ process for the downlink communication. As another example, the base station 110 may indicate that the UE 120 is to use a storage-required HARQ process for the retransmission based at least in part on determining that the UE 120 used a storage-free HARQ process for the downlink communication. In some aspects, the base station 110 may indicate that the UE 120 is to use a storage-required HARQ process for the retransmission based at least in part on determining that a storage-required HARQ process is available for the retransmission.

As indicated above, Figs. 4A and 4B are provided as one or more examples. Other examples may differ from what is described with respect to Figs. 4A and 4B.

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 a storage-free HARQ process.

As shown in Fig. 5, in some aspects, process 500 may include receiving, from a base station, a configuration of one or more storage-free HARQ processes for which the UE is not required to store decoding error soft bits (block 510) . For example, the UE (e.g., using reception component 902, depicted in Fig. 9) may receive, from a base station, a configuration of one or more storage-free HARQ processes for which the UE is not required to store decoding error soft bits, as described above.

As further shown in Fig. 5, in some aspects, process 500 may include communicating with the base station using the one or more storage-free HARQ processes (block 520) . For example, the UE (e.g., using reception component 902 and/or transmission component 904, depicted in Fig. 9) may communicate with the base station using the one or more storage-free HARQ processes, 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 UE is a reduced capability UE. In a second aspect, alone or in combination with the first aspect, the one or more storage-free HARQ processes are permitted to be used for at least one of unicast communication or multicast communication. In a third aspect, alone or in combination with one or more of the first and second aspects, process 500 includes transmitting (e.g., using transmission component 904, depicted in Fig. 9) , to the base station, an indication of a UE capability for processing a quantity of storage-free HARQ processes. In a fourth aspect, alone or in combination with one or more of the first through third aspects, a quantity of the one or more storage-free HARQ processes is based at least in part on the UE capability. In a fifth aspect, alone or in combination with one or more of the first through fourth aspects, process 500 includes receiving (e.g., using reception component 902, depicted in Fig. 9) , from the base station, a configuration of one or more storage-required HARQ processes for which the UE is required to store decoding error soft bits, and communicating with the base station using the one or more storage-required HARQ processes.

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 a storage-free HARQ process.

As shown in Fig. 6, in some aspects, process 600 may include transmitting, to a UE, a configuration of one or more storage-free HARQ processes for which the UE is not required to store decoding error soft bits (block 610) . For example, the base station (e.g., using transmission component 1004, depicted in Fig. 10) may transmit, to a UE, a configuration of one or more storage-free HARQ processes for which the UE is not required to store decoding error soft bits, as described above.

As further shown in Fig. 6, in some aspects, process 600 may include communicating with the UE using the one or more storage-free HARQ processes (block 620) . For example, the base station (e.g., using reception component 1002 and/or transmission component 1004, depicted in Fig. 10) may communicate with the UE using the one or more storage-free HARQ processes, 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 UE is a reduced capability UE. In a second aspect, alone or in combination with the first aspect, the one or more storage-free HARQ processes are permitted to be used for at least one of unicast communication or multicast communication. In a third aspect, alone or in combination with one or more of the first and second aspects, process 600 includes receiving (e.g., using reception component 1002, depicted in Fig. 10) , from the UE, an indication of a UE capability for processing a quantity of storage-free HARQ processes, and configuring a quantity of the one or more storage-free HARQ processes based at least in part on the UE capability. In a fourth aspect, alone or in combination with one or more of the first through third aspects, process 600 includes transmitting (e.g., using transmission component 1004, depicted in Fig. 10) , to the UE, a configuration of one or more storage-required HARQ processes for which the UE is required to store decoding error soft bits, and communicating with the UE using the one or more storage-required HARQ processes.

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 diagram illustrating an example process 700 performed, for example, by a UE, in accordance with various aspects of the present disclosure. Example process 700 is an example where the UE (e.g., UE 120) performs operations associated with a storage-free HARQ process.

As shown in Fig. 7, in some aspects, process 700 may include determining to use a storage-free HARQ process for a downlink communication received from a base station (block 710) . For example, the UE (e.g., using determination component 1108, depicted in Fig. 11) may determine to use a storage-free HARQ process for a downlink communication received from a base station, as described above.

As further shown in Fig. 7, in some aspects, process 700 may include transmitting, to the base station, HARQ feedback for the downlink communication based at least in part on the storage-free HARQ process (block 720) . For example, the UE (e.g., using transmission component 1102, depicted in Fig. 11) may transmit, to the base station, HARQ feedback for the downlink communication based at least in part on the storage-free HARQ process, as described above.

Process 700 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, process 700 includes determining (e.g., using determination component 1108, depicted in Fig. 11) a decoding error for the downlink communication, and refraining from storing soft bits for the decoding error based at least in part on determining to use the storage-free HARQ process. In a second aspect, alone or in combination with the first aspect, the downlink communication is a unicast communication. In a third aspect, alone or in combination with one or more of the first and second aspects, the downlink communication is a multicast communication. In a fourth aspect, alone or in combination with one or more of the first through third aspects, determining to use the storage-free HARQ process comprises determining to use the storage-free HARQ process based at least in part on receiving, from the base station, an indication to use the storage-free HARQ process for the downlink communication.

In a fifth aspect, alone or in combination with one or more of the first through fourth aspects, transmitting the HARQ feedback for the downlink communication comprises transmitting a legacy NACK for the downlink communication based at least in part on receiving the indication to use the storage-free HARQ process for the downlink communication. In a sixth aspect, alone or in combination with one or more of the first through fifth aspects, the indication to use the storage-free HARQ process for the downlink communication comprises a HARQ process identifier included in a range of HARQ process identifiers that are configured for storage-free HARQ.

In a seventh aspect, alone or in combination with one or more of the first through sixth aspects, the indication to use the storage-free HARQ process for the downlink communication comprises an explicit indication to use the storage-free HARQ process for the downlink communication, and the explicit indication to use the storage-free HARQ process for the downlink communication comprises a field, in a scheduling communication for the downlink communication, that is configured to indicate whether the UE is to use the storage-free HARQ process. In an eighth aspect, alone or in combination with one or more of the first through seventh aspects, determining to use the storage-free HARQ process comprises determining to use the storage-free HARQ process based at least in part on at least one of a determination that no storage-required HARQ processes for the UE are available, a priority associated with the downlink communication, or a communication type associated with the downlink communication.

In a ninth aspect, alone or in combination with one or more of the first through eighth aspects, transmitting the HARQ feedback for the downlink communication comprises transmitting a NACK specific to storage-free HARQ based at least in part on determining to use the storage-free HARQ process for the downlink communication, wherein the NACK specific to storage-free HARQ indicates that the UE used the storage-free HARQ process for the downlink communication. In a tenth aspect, alone or in combination with one or more of the first through ninth aspects, process 700 includes receiving (e.g., using reception component 1102, depicted in Fig. 11) , from the base station, a retransmission of the downlink communication based at least in part on the HARQ feedback, wherein an RV for the retransmission is a same RV as an RV for an initial transmission of the downlink communication. In an eleventh aspect, alone or in combination with one or more of the first through tenth aspects, process 700 includes receiving (e.g., using reception component 1102, depicted in Fig. 11) , from the base station, a retransmission of the downlink communication based at least in part on the HARQ feedback, and receiving, from the base station, an indication to use a storage-required HARQ process for the retransmission.

Although Fig. 7 shows example blocks of process 700, in some aspects, process 700 may include additional blocks, fewer blocks, different blocks, or differently arranged blocks than those depicted in Fig. 7. Additionally, or alternatively, two or more of the blocks of process 700 may be performed in parallel.

Fig. 8 is a diagram illustrating an example process 800 performed, for example, by a base station, in accordance with various aspects of the present disclosure. Example process 800 is an example where the base station (e.g., base station 110) performs operations associated with a storage-free HARQ process.

As shown in Fig. 8, in some aspects, process 800 may include transmitting, to a UE, an indication to use a storage-free HARQ process for a downlink communication transmitted to the UE (block 810) . For example, the base station (e.g., using transmission component 1202, depicted in Fig. 12) may transmit, to a UE, an indication to use a storage-free HARQ process for a downlink communication transmitted to the UE, as described above.

As further shown in Fig. 8, in some aspects, process 800 may include receiving, from the UE, HARQ feedback for the downlink communication based at least in part on the storage-free HARQ process (block 820) . For example, the base station (e.g., using reception component 1202, depicted in Fig. 12) may receive, from the UE, HARQ feedback for the downlink communication based at least in part on the storage-free HARQ process, as described above.

Process 800 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, receiving the HARQ feedback for the downlink communication comprises receiving a legacy NACK for the downlink communication based at least in part on transmitting the indication to use the storage-free HARQ process for the downlink communication. In a second aspect, alone or in combination with the first aspect, the indication to use the storage-free HARQ process for the downlink communication comprises a HARQ process identifier included in a range of HARQ process identifiers that are configured for storage-free HARQ. In a third aspect, alone or in combination with one or more of the first and second aspects, the indication to use the storage-free HARQ process for the downlink communication comprises an explicit indication to use the storage-free HARQ process for the downlink communication, and the explicit indication to use the storage-free HARQ process for the downlink communication comprises a field, in a scheduling communication for the downlink communication, that is configured to indicate whether the UE is to use the storage-free HARQ process.

In a fourth aspect, alone or in combination with one or more of the first through third aspects, transmitting the indication to use the storage-free HARQ process comprises transmitting the indication to use the storage-free HARQ process based at least in part on at least one of a determination that no storage-required HARQ processes for the UE are available, a priority associated with the downlink communication, or a communication type associated with the downlink communication. In a fifth aspect, alone or in combination with one or more of the first through fourth aspects, process 800 includes transmitting (e.g., using transmission component 1204, depicted in Fig. 12) , to the UE, a retransmission of the downlink communication based at least in part on the HARQ feedback, wherein an RV for the retransmission is a same RV as an RV for an initial transmission of the downlink communication. In a sixth aspect, alone or in combination with one or more of the first through fifth aspects, process 800 includes transmitting (e.g., using transmission component 1204, depicted in Fig. 12) , to the UE, a retransmission of the downlink communication based at least in part on the HARQ feedback, and transmitting, to the UE, an indication to use a storage-required HARQ process for the retransmission.

Although Fig. 8 shows example blocks of process 800, in some aspects, process 800 may include additional blocks, fewer blocks, different blocks, or differently arranged blocks than those depicted in Fig. 8. Additionally, or alternatively, two or more of the blocks of process 800 may be performed in parallel.

Fig. 9 is a block diagram of an example apparatus 900 for wireless communication. The apparatus 900 may be a UE, or a UE may include the apparatus 900. In some aspects, the apparatus 900 includes a reception component 902 and a transmission component 904, 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 900 may communicate with another apparatus 906 (such as a UE, a base station, or another wireless communication device) using the reception component 902 and the transmission component 904.

In some aspects, the apparatus 900 may be configured to perform one or more operations described herein in connection with Figs. 3A, 3B, 4A, and/or 4B. Additionally or alternatively, the apparatus 900 may be configured to perform one or more processes described herein, such as process 500 of Fig. 5. In some aspects, the apparatus 900 and/or one or more components shown in Fig. 9 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. 9 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 902 may receive communications, such as reference signals, control information, data communications, or a combination thereof, from the apparatus 906. The reception component 902 may provide received communications to one or more other components of the apparatus 900. In some aspects, the reception component 902 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 906. In some aspects, the reception component 902 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 904 may transmit communications, such as reference signals, control information, data communications, or a combination thereof, to the apparatus 906. In some aspects, one or more other components of the apparatus 906 may generate communications and may provide the generated communications to the transmission component 904 for transmission to the apparatus 906. In some aspects, the transmission component 904 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 906. In some aspects, the transmission component 904 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 904 may be collocated with the reception component 902 in a transceiver.

The reception component 902 may receive, from the apparatus 906, a configuration of one or more storage-free HARQ processes for which the apparatus 900 is not required to store decoding error soft bits. The reception component 902 and/or the transmission component 904 may communicate with the apparatus 906 using the one or more storage-free HARQ processes. The transmission component 904 may transmit, to the apparatus 906, an indication of a UE capability for processing a quantity of storage-free HARQ processes. The reception component 902 may receive, from the apparatus 906, a configuration of one or more storage-required HARQ processes for which the UE is required to store decoding error soft bits. The reception component 902 and/or the transmission component 904 may communicate with the apparatus 906 using the one or more storage-required HARQ processes.

The number and arrangement of components shown in Fig. 9 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. 9. Furthermore, two or more components shown in Fig. 9 may be implemented within a single component, or a single component shown in Fig. 9 may be implemented as multiple, distributed components. Additionally or alternatively, a set of (one or more) components shown in Fig. 9 may perform one or more functions described as being performed by another set of components shown in Fig. 9.

Fig. 10 is a block diagram of an example apparatus 1000 for wireless communication. The apparatus 1000 may be a base station, or a base station may include the apparatus 1000. In some aspects, the apparatus 1000 includes a reception component 1002 and a transmission component 1004, 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 1000 may communicate with another apparatus 1006 (such as a UE, a base station, or another wireless communication device) using the reception component 1002 and the transmission component 1004. As further shown, the apparatus 1000 may include a configuration component 1008.

In some aspects, the apparatus 1000 may be configured to perform one or more operations described herein in connection with Figs. 3A, 3B, 4A, and/or 4B. Additionally or alternatively, the apparatus 1000 may be configured to perform one or more processes described herein, such as process 600 of Fig. 6. In some aspects, the apparatus 1000 and/or one or more components shown in Fig. 10 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. 10 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 1002 may receive communications, such as reference signals, control information, data communications, or a combination thereof, from the apparatus 1006. The reception component 1002 may provide received communications to one or more other components of the apparatus 1000. In some aspects, the reception component 1002 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 1006. In some aspects, the reception component 1002 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 1004 may transmit communications, such as reference signals, control information, data communications, or a combination thereof, to the apparatus 1006. In some aspects, one or more other components of the apparatus 1006 may generate communications and may provide the generated communications to the transmission component 1004 for transmission to the apparatus 1006. In some aspects, the transmission component 1004 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 1006. In some aspects, the transmission component 1004 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 1004 may be collocated with the reception component 1002 in a transceiver.

The transmission component 1004 may transmit, to the apparatus 1006, a configuration of one or more storage-free HARQ processes for which the apparatus 1006 is not required to store decoding error soft bits. The reception component 1002 and/or the transmission component 1004 may communicate with the apparatus 1006 using the one or more storage-free HARQ processes. The reception component 1002 may receive, from the apparatus 1006, an indication of a UE capability for processing a quantity of storage-free HARQ processes. The configuration component 1008 may configure a quantity of the one or more storage-free HARQ processes based at least in part on the UE capability. In some aspects, the configuration component 1008 may include a receive processor, a transmit processor, a controller/processor, a memory, or a combination thereof, of the base station described above in connection with Fig. 2.

The transmission component 1004 may transmit, to the apparatus 1006, a configuration of one or more storage-required HARQ processes for which the apparatus 1006 is required to store decoding error soft bits. The receive component 1002 and/or the transmission component 1004 may communicate with the apparatus 1006 using the one or more storage-required HARQ processes.

The number and arrangement of components shown in Fig. 10 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. 10. Furthermore, two or more components shown in Fig. 10 may be implemented within a single component, or a single component shown in Fig. 10 may be implemented as multiple, distributed components. Additionally or alternatively, a set of (one or more) components shown in Fig. 10 may perform one or more functions described as being performed by another set of components shown in Fig. 10.

Fig. 11 is a block diagram of an example apparatus 1100 for wireless communication. The apparatus 1100 may be a UE, or a UE may include the apparatus 1100. In some aspects, the apparatus 1100 includes a reception component 1102 and a transmission component 1104, 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 1100 may communicate with another apparatus 1106 (such as a UE, a base station, or another wireless communication device) using the reception component 1102 and the transmission component 1104. As further shown, the apparatus 1100 may include a determination component 1108.

In some aspects, the apparatus 1100 may be configured to perform one or more operations described herein in connection with Figs. 3A, 3B, 4A, and/or 4B. Additionally or alternatively, the apparatus 1100 may be configured to perform one or more processes described herein, such as process 700 of Fig. 7. In some aspects, the apparatus 1100 and/or one or more components shown in Fig. 11 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. 11 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 1102 may receive communications, such as reference signals, control information, data communications, or a combination thereof, from the apparatus 1106. The reception component 1102 may provide received communications to one or more other components of the apparatus 1100. In some aspects, the reception component 1102 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 1106. In some aspects, the reception component 1102 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 1104 may transmit communications, such as reference signals, control information, data communications, or a combination thereof, to the apparatus 1106. In some aspects, one or more other components of the apparatus 1106 may generate communications and may provide the generated communications to the transmission component 1104 for transmission to the apparatus 1106. In some aspects, the transmission component 1104 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 1106. In some aspects, the transmission component 1104 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 1104 may be collocated with the reception component 1102 in a transceiver.

The determination component 1108 may determine to use a storage-free HARQ process for a downlink communication received from the apparatus 1108. In some aspects, the determination component 1108 may include a receive processor, a transmit processor, a controller/processor, a memory, or a combination thereof, of the UE described above in connection with Fig. 2. The transmission component 1104 may transmit, to the apparatus 1108, HARQ feedback for the downlink communication based at least in part on the storage-free HARQ process. The determination component 1108 may determine a decoding error for the downlink communication. The apparatus 1100 may refrain from storing soft bits for the decoding error based at least in part on the determination of the determination component 1108 to use the storage-free HARQ process.

The reception component 1102 may receive, from the apparatus 1106, a retransmission of the downlink communication based at least in part on the HARQ feedback, wherein an RV for the retransmission is a same RV as an RV for an initial transmission of the downlink communication. The reception component 1102 may receive, from the apparatus 1106, a retransmission of the downlink communication based at least in part on the HARQ feedback. The reception component 1102 may receive, from the apparatus 1106, an indication to use a storage-required HARQ process for the retransmission.

The number and arrangement of components shown in Fig. 11 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. 11. Furthermore, two or more components shown in Fig. 11 may be implemented within a single component, or a single component shown in Fig. 11 may be implemented as multiple, distributed components. Additionally or alternatively, a set of (one or more) components shown in Fig. 11 may perform one or more functions described as being performed by another set of components shown in Fig. 11.

Fig. 12 is a block diagram of an example apparatus 1200 for wireless communication. The apparatus 1200 may be a base station, or a base station may include the apparatus 1200. In some aspects, the apparatus 1200 includes a reception component 1202 and a transmission component 1204, 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 1200 may communicate with another apparatus 1206 (such as a UE, a base station, or another wireless communication device) using the reception component 1202 and the transmission component 1204.

In some aspects, the apparatus 1200 may be configured to perform one or more operations described herein in connection with Figs. 3A, 3B, 4A, and/or 4B. Additionally or alternatively, the apparatus 1200 may be configured to perform one or more processes described herein, such as process 800 of Fig. 8 or a combination thereof. In some aspects, the apparatus 1200 and/or one or more components shown in Fig. 12 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. 12 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 1202 may receive communications, such as reference signals, control information, data communications, or a combination thereof, from the apparatus 1206. The reception component 1202 may provide received communications to one or more other components of the apparatus 1200. In some aspects, the reception component 1202 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 1206. In some aspects, the reception component 1202 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 1204 may transmit communications, such as reference signals, control information, data communications, or a combination thereof, to the apparatus 1206. In some aspects, one or more other components of the apparatus 1206 may generate communications and may provide the generated communications to the transmission component 1204 for transmission to the apparatus 1206. In some aspects, the transmission component 1204 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 1206. In some aspects, the transmission component 1204 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 1204 may be collocated with the reception component 1202 in a transceiver.

The transmission component 1204 may transmit, to the apparatus 1206, an indication to use a storage-free HARQ process for a downlink communication transmitted to the apparatus 1206. The reception component 1202 may receive, from the apparatus 1206, HARQ feedback for the downlink communication based at least in part on the storage-free HARQ process. The transmission component 1204 may transmit, to the apparatus 1206, a retransmission of the downlink communication based at least in part on the HARQ feedback wherein an RV for the retransmission is a same RV as an RV for an initial transmission of the downlink communication. The transmission component 1204 may transmit, to the apparatus 1206, a retransmission of the downlink communication based at least in part on the HARQ feedback. The transmission component 1204 may transmit, to the apparatus 1206, an indication to use a storage-required HARQ process for the retransmission.

The number and arrangement of components shown in Fig. 12 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. 12. Furthermore, two or more components shown in Fig. 12 may be implemented within a single component, or a single component shown in Fig. 12 may be implemented as multiple, distributed components. Additionally or alternatively, a set of (one or more) components shown in Fig. 12 may perform one or more functions described as being performed by another set of components shown in Fig. 12.

The foregoing disclosure provides illustration and description, but is not intended to be exhaustive or to limit the aspects to the precise form 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, firmware, and/or a combination of hardware and software. As used herein, a processor is implemented in hardware, firmware, 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, firmware, 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, and/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. 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, a combination of related and unrelated items, and/or the like) , 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, ” and/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

A method of wireless communication performed by a user equipment (UE) , comprising:

receiving, from a base station, a configuration of one or more storage-free hybrid automatic repeat request (HARQ) processes for which the UE is not required to store decoding error soft bits; and

communicating with the base station using the one or more storage-free HARQ processes.
The method of claim 1, wherein the UE is a reduced capability UE.
The method of claim 1, wherein the one or more storage-free HARQ processes are permitted to be used for at least one of unicast communication or multicast communication.
The method of claim 1, further comprising:

transmitting, to the base station, an indication of a UE capability for processing a quantity of storage-free HARQ processes.
The method of claim 4, wherein a quantity of the one or more storage-free HARQ processes is based at least in part on the UE capability.
The method of claim 1, further comprising:

receiving, from the base station, a configuration of one or more storage-required HARQ processes for which the UE is required to store decoding error soft bits; and

communicating with the base station using the one or more storage-required HARQ processes.
A method of wireless communication performed by a base station, comprising:

transmitting, to a user equipment (UE) , a configuration of one or more storage-free hybrid automatic repeat request (HARQ) processes for which the UE is not required to store decoding error soft bits; and

communicating with the UE using the one or more storage-free HARQ processes.
The method of claim 7, wherein the UE is a reduced capability UE.
The method of claim 7, wherein the one or more storage-free HARQ processes are permitted to be used for at least one of unicast communication or multicast communication.
The method of claim 7, further comprising:

receiving, from the UE, an indication of a UE capability for processing a quantity of storage-free HARQ processes; and

configuring a quantity of the one or more storage-free HARQ processes based at least in part on the UE capability.
The method of claim 7, further comprising:

transmitting, to the UE, a configuration of one or more storage-required HARQ processes for which the UE is required to store decoding error soft bits; and

communicating with the UE using the one or more storage-required HARQ processes.
A method of wireless communication performed by a user equipment (UE) , comprising:

determining to use a storage-free hybrid automatic repeat request (HARQ) process for a downlink communication received from a base station; and

transmitting, to the base station, HARQ feedback for the downlink communication based at least in part on the storage-free HARQ process.
The method of claim 12, further comprising:

determining a decoding error for the downlink communication; and

refraining from storing soft bits for the decoding error based at least in part on determining to use the storage-free HARQ process.
The method of claim 12, wherein the downlink communication is a unicast communication.
The method of claim 12, wherein the downlink communication is a multicast communication.
The method of claim 12, wherein determining to use the storage-free HARQ process comprises:

determining to use the storage-free HARQ process based at least in part on receiving, from the base station, an indication to use the storage-free HARQ process for the downlink communication.
The method of claim 16, wherein transmitting the HARQ feedback for the downlink communication comprises:

transmitting a legacy negative acknowledgement (NACK) for the downlink communication based at least in part on receiving the indication to use the storage-free HARQ process for the downlink communication.
The method of claim 16, wherein the indication to use the storage-free HARQ process for the downlink communication comprises a HARQ process identifier included in a range of HARQ process identifiers that are configured for storage-free HARQ.
The method of claim 16, wherein the indication to use the storage-free HARQ process for the downlink communication comprises an explicit indication to use the storage-free HARQ process for the downlink communication; and

wherein the explicit indication to use the storage-free HARQ process for the downlink communication comprises a field, in a scheduling communication for the downlink communication, that is configured to indicate whether the UE is to use the storage-free HARQ process.
The method of claim 12, wherein determining to use the storage-free HARQ process comprises:

determining to use the storage-free HARQ process based at least in part on at least one of:

a determination that no storage-required HARQ processes for the UE are available,

a priority associated with the downlink communication, or

a communication type associated with the downlink communication.
The method of claim 12, wherein transmitting the HARQ feedback for the downlink communication comprises:

transmitting a negative acknowledgement (NACK) specific to storage-free HARQ based at least in part on determining to use the storage-free HARQ process for the downlink communication,

wherein the NACK specific to storage-free HARQ indicates that the UE used the storage-free HARQ process for the downlink communication.
The method of claim 12, further comprising:

receiving, from the base station, a retransmission of the downlink communication based at least in part on the HARQ feedback,

wherein a redundancy version (RV) for the retransmission is a same RV as an RV for an initial transmission of the downlink communication.
The method of claim 12, further comprising:

receiving, from the base station, a retransmission of the downlink communication based at least in part on the HARQ feedback; and

receiving, from the base station, an indication to use a storage-required HARQ process for the retransmission.
A method of wireless communication performed by a base station, comprising:

transmitting, to a user equipment (UE) , an indication to use a storage-free hybrid automatic repeat request (HARQ) process for a downlink communication transmitted to the UE; and

receiving, from the UE, HARQ feedback for the downlink communication based at least in part on the storage-free HARQ process.
The method of claim 24, wherein receiving the HARQ feedback for the downlink communication comprises:

receiving a legacy negative acknowledgement (NACK) for the downlink communication based at least in part on transmitting the indication to use the storage-free HARQ process for the downlink communication.
The method of claim 24, wherein the indication to use the storage-free HARQ process for the downlink communication comprises a HARQ process identifier included in a range of HARQ process identifiers that are configured for storage-free HARQ.
The method of claim 24, wherein the indication to use the storage-free HARQ process for the downlink communication comprises an explicit indication to use the storage-free HARQ process for the downlink communication; and

wherein the explicit indication to use the storage-free HARQ process for the downlink communication comprises a field, in a scheduling communication for the downlink communication, that is configured to indicate whether the UE is to use the storage-free HARQ process.
The method of claim 24, wherein transmitting the indication to use the storage-free HARQ process comprises:

transmitting the indication to use the storage-free HARQ process based at least in part on at least one of:

a determination that no storage-required HARQ processes for the UE are available,

a priority associated with the downlink communication, or

a communication type associated with the downlink communication.
The method of claim 24, further comprising:

transmitting, to the UE, a retransmission of the downlink communication based at least in part on the HARQ feedback,

wherein a redundancy version (RV) for the retransmission is a same RV as an RV for an initial transmission of the downlink communication.
The method of claim 24, further comprising:

transmitting, to the UE, a retransmission of the downlink communication based at least in part on the HARQ feedback; and

transmitting, to the UE, an indication to use a storage-required HARQ process for the retransmission.
An apparatus for wireless communication, comprising:

means for receiving, from a base station, a configuration of one or more storage-free hybrid automatic repeat request (HARQ) processes for which the apparatus is not required to store decoding error soft bits; and

means for communicating with the base station using the one or more storage-free HARQ processes.
An apparatus for wireless communication, comprising:

means for transmitting, to a user equipment (UE) , a configuration of one or more storage-free hybrid automatic repeat request (HARQ) processes for which the UE is not required to store decoding error soft bits; and

means for communicating with the UE using the one or more storage-free HARQ processes.
An apparatus for wireless communication, comprising:

means for determining to use a storage-free hybrid automatic repeat request (HARQ) process for a downlink communication received from a base station; and

means for transmitting, to the base station, HARQ feedback for the downlink communication based at least in part on the storage-free HARQ process.
An apparatus for wireless communication, comprising:

means for transmitting, to a user equipment (UE) , an indication to use a storage-free hybrid automatic repeat request (HARQ) process for a downlink communication transmitted to the UE; and

means for receiving, from the UE, HARQ feedback for the downlink communication based at least in part on the storage-free HARQ process.
A user equipment (UE) for wireless communication, comprising:

memory;

one or more processors coupled to the memory; and

instructions stored in the memory and operable, when executed by the one or more processors, to cause the UE to:

receive, from a base station, a configuration of one or more storage-free hybrid automatic repeat request (HARQ) processes for which the UE is not required to store decoding error soft bits; and

communicate with the base station using the one or more storage-free HARQ processes.
A base station for wireless communication, comprising:

memory;

one or more processors coupled to the memory; and

instructions stored in the memory and operable, when executed by the one or more processors, to cause the base station to:

transmit, to a user equipment (UE) , a configuration of one or more storage-free hybrid automatic repeat request (HARQ) processes for which the UE is not required to store decoding error soft bits; and

communicate with the UE using the one or more storage-free HARQ processes.
A UE for wireless communication, comprising:

memory;

one or more processors coupled to the memory; and

instructions stored in the memory and operable, when executed by the one or more processors, to cause the UE to:

determine to use a storage-free hybrid automatic repeat request (HARQ) process for a downlink communication received from a base station; and

transmit, to the base station, HARQ feedback for the downlink communication based at least in part on the storage-free HARQ process.
A base station for wireless communication, comprising:

memory;

one or more processors coupled to the memory; and

instructions stored in the memory and operable, when executed by the one or more processors, to cause the base station to:

transmit, to a user equipment (UE) , an indication to use a storage-free hybrid automatic repeat request (HARQ) process for a downlink communication transmitted to the UE; and

receive, from the UE, HARQ feedback for the downlink communication based at least in part on the storage-free HARQ process.
A non-transitory computer-readable medium storing one or more instructions for wireless communication that, when executed by one or more processors of a user equipment (UE) , cause the UE to:

receive, from a base station, a configuration of one or more storage-free hybrid automatic repeat request (HARQ) processes for which the UE is not required to store decoding error soft bits; and

communicate with the base station using the one or more storage-free HARQ processes.
A non-transitory computer-readable medium storing one or more instructions for wireless communication that, when executed by one or more processors of a base station, cause the base station to:

transmit, to a user equipment (UE) , a configuration of one or more storage-free hybrid automatic repeat request (HARQ) processes for which the UE is not required to store decoding error soft bits; and

communicate with the UE using the one or more storage-free HARQ processes.
A non-transitory computer-readable medium storing one or more instructions for wireless communication that, when executed by one or more processors of an UE, cause the UE to:

determine to use a storage-free hybrid automatic repeat request (HARQ) process for a downlink communication received from a base station; and

transmit, to the base station, HARQ feedback for the downlink communication based at least in part on the storage-free HARQ process.
A non-transitory computer-readable medium storing one or more instructions for wireless communication that, when executed by one or more processors of a base station, cause the base station to:

transmit, to a user equipment (UE) , an indication to use a storage-free hybrid automatic repeat request (HARQ) process for a downlink communication transmitted to the UE; and

receive, from the UE, HARQ feedback for the downlink communication based at least in part on the storage-free HARQ process.