Additional details for sub-slot based type-1 hybrid automatic repeat request (HARQ)-acknowledgement (ACK) codebook generation

This disclosure provides systems, methods, and devices for wireless communication that support sub-slot based Type-1 hybrid automatic repeat request (HARQ) feedback codebook generation. In aspects, techniques are provided for generating a set of candidate physical downlink shared channel (PDSCH) reception occasions for an active bandwidth part (BWP) of a downlink (DL) serving cell. In aspects, a user equipment (UE) obtains a set of UL sub-slots based, at least in part, on a set of K1 values, and then determines, for each UL sub-slot in the set of UL sub-slots, whether the UL sub-slots satisfy a predetermined overlapping condition with a current DL slot. A PDSCH reception occasions set is generated based, at least in part, on a set of time domain resource allocation (TDRA) candidates of the current DL slot and a determination that a current UL sub-slot satisfies the predetermined overlapping condition with the current DL slot.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of European Patent Application No. 21172152.7, entitled, “ADDITIONAL DETAILS FOR SUB-SLOT BASED TYPE-1 HYBRID AUTOMATIC REPEAT REQUEST (HARD)-ACKNOWLEDGEMENT (ACK) CODEBOOK GENERATION,” filed on May 4, 2021, which is expressly incorporated by reference herein in its entirety.

BACKGROUND

Field

Aspects of the present disclosure relate generally to wireless communication systems, and more particularly, to hybrid automatic repeat request (HARD) feedback codebook generation.

Background

A wireless communication network may include a number of base stations or nodeBs that can support communication for a number of user equipments (UEs). A UE may communicate with a base station via downlink and uplink. The downlink (or forward link) refers to the communication link from the base station to the UE, and the uplink (or reverse link) refers to the communication link from the UE to the base station.

As the demand for mobile broadband access continues to increase, the possibilities of interference and congested networks grows with more UEs accessing the long-range wireless communication networks and more short-range wireless systems being deployed in communities. Research and development continue to advance wireless technologies not only to meet the growing demand for mobile broadband access, but to advance and enhance the user experience with mobile communications. It is desirable to provide mechanisms to support a more robust set functionality to handle the increasing needs and complexities of wireless communication systems. For example, aspects of the present disclosure provide a mechanism to support sub-slot based Type-1 HARQ feedback codebook generation, which enable a system to provide improved services, as discussed in the present disclosure.

SUMMARY

Various aspects of the present disclosure are directed to systems and methods for supporting sub-slot based Type-1 HARQ feedback codebook generation. In aspects, techniques are provided for constructing and/or generating a set of candidate PDSCH reception occasions for an active bandwidth part (BWP) of a DL serving cell that may be used for generating a HARQ feedback codebook.

The techniques described in aspects of the present disclosure may address problems with current approaches for HARQ feedback codebook generation, as will be described in more detail below. In particular, the techniques herein address the problems that arise when mixed numerology and arbitrary UL sub-slot configuration is used, such as when an uplink slot length is not a multiple of downlink slots, or a downlink slot length is not a multiple of uplink slots, as in the case when there is a partial overlapping between uplink and downlink slots (e.g., when an uplink slot is not fully contained within a single downlink slot, or when a downlink slot is not fully contained within a single uplink slot). In addition, the techniques described herein may also address problems that arise in HARQ feedback codebook generation in current implementations that check whether the condition of a k1 value satisfy mod(nv−k1+1,NULDL)=0 and may not allow a UE to transmit HARQ feedback in every slot, thereby incurring unnecessary latency. Additionally, the techniques described herein may also address problems that arise in current approaches that incur a large redundancy when the uplink slots are not aligned with downlink slots, as in this case a UE may insert dummy uplink slots to align with a downlink slot.

In one aspect of the disclosure, a method of wireless communication includes determining, by a user equipment (UE), to generate a feedback codebook to be transmitted to a base station in a feedback uplink (UL) sub-slot of a plurality of UL sub-slots of an UL slot, obtaining a set of UL sub-slots based, at least in part, on the feedback UL sub-slot and a set of K1 values, each UL sub-slot in the set of UL sub-slots associated with a different K1 value of the set of K1 values, determining, for each UL sub-slot in the set of UL sub-slots, whether a current UL sub-slot in the set of UL sub-slots satisfies a predetermined overlapping condition with a current downlink (DL) slot, the current DL slot configured with a set of time domain resource allocation (TDRA) candidates, generating a set of physical downlink shared channel (PDSCH) reception occasions based, at least in part, on the set of TDRA candidates of the current DL slot and a determination that the current UL sub-slot satisfies the predetermined overlapping condition with the current DL slot, and constructing the feedback codebook based on the set of PDSCH reception occasions.

In an additional aspect of the disclosure, an apparatus includes at least one processor and a memory coupled to the at least one processor. The memory stores processor-readable code that, when executed by the at least one processor, is configured to perform operations including determining, by a UE, to generate a feedback codebook to be transmitted to a base station in a feedback UL sub-slot of a plurality of UL sub-slots of an UL slot, obtaining a set of UL sub-slots based, at least in part, on the feedback UL sub-slot and a set of K1 values, each UL sub-slot in the set of UL sub-slots associated with a different K1 value of the set of K1 values, determining, for each UL sub-slot in the set of UL sub-slots, whether a current UL sub-slot in the set of UL sub-slots satisfies a predetermined overlapping condition with a current DL slot, the current DL slot configured with a set of TDRA candidates, generating a set of PDSCH reception occasions based, at least in part, on the set of TDRA candidates of the current DL slot when the current UL sub-slot satisfies the predetermined overlapping condition with the current DL slot, and constructing the feedback codebook based on the set of PDSCH reception occasions.

In an additional aspect of the disclosure, a non-transitory computer-readable medium stores instructions that, when executed by a processor, cause the processor to perform operations. The operations include determining, by a UE, to generate a feedback codebook to be transmitted to a base station in a feedback UL sub-slot of a plurality of UL sub-slots of an UL slot, obtaining a set of UL sub-slots based, at least in part, on the feedback UL sub-slot and a set of K1 values, each UL sub-slot in the set of UL sub-slots associated with a different K1 value of the set of K1 values, determining, for each UL sub-slot in the set of UL sub-slots, whether a current UL sub-slot in the set of UL sub-slots satisfies a predetermined overlapping condition with a current DL slot, the current DL slot configured with a set of TDRA candidates, generating a set of PDSCH reception occasions based, at least in part, on the set of TDRA candidates of the current DL slot and a determination that the current UL sub-slot satisfies the predetermined overlapping condition with the current DL slot, and constructing the feedback codebook based on the set of PDSCH reception occasions.

In an additional aspect of the disclosure, an apparatus includes means for determining, by a UE, to generate a feedback codebook to be transmitted to a base station in a feedback UL sub-slot of a plurality of UL sub-slots of an UL slot, means for obtaining a set of UL sub-slots based, at least in part, on the feedback UL sub-slot and a set of K1 values, each UL sub-slot in the set of UL sub-slots associated with a different K1 value of the set of K1 values, means for determining, for each UL sub-slot in the set of UL sub-slots, whether a current UL sub-slot in the set of UL sub-slots satisfies a predetermined overlapping condition with a current DL slot, the current DL slot configured with a set of TDRA candidates, means for generating a set of PDSCH reception occasions based, at least in part, on the set of TDRA candidates of the current DL slot and a determination that the current UL sub-slot satisfies the predetermined overlapping condition with the current DL slot, and means for constructing the feedback codebook based on the set of PDSCH reception occasions.

DETAILED DESCRIPTION

As used herein, a network entity may be or may include a base station and/or functionality of a base station. In aspects a network entity, network node, network equipment, mobility element of wireless network100, etc., may be implemented in an aggregated or monolithic base station architecture, or alternatively, in a disaggregated base station architecture, and may include one or more of a central unit (CU), a distributed unit (DU), a radio unit (RU), a Near-Real Time (Near-RT) RAN Intelligent Controller (MC), or a Non-Real Time (Non-RT) MC, etc.

Each base station105may be associated with a particular geographic coverage area in which communications with various UEs115is supported. Each base station105may provide communication coverage for a respective geographic coverage area via communication links, and communication links between a base station105and a UE115may utilize one or more carriers. Communication links in wireless communications system100may include uplink transmissions from a UE115to a base station105, or downlink transmissions from a base station105to a UE115. Downlink transmissions may also be referred to as forward link transmissions while uplink transmissions may also be referred to as reverse link transmissions.

The geographic coverage area for a base station105may be divided into sectors making up a portion of the geographic coverage area, and each sector may be associated with a cell. For example, each base station105may provide communication coverage for a macro cell, a small cell, a hot spot, or other types of cells, or various combinations thereof. In some examples, a base station105may be movable and, therefore, provide communication coverage for a moving geographic coverage area. In some examples, different geographic coverage areas associated with different technologies may overlap, and overlapping geographic coverage areas associated with different technologies may be supported by the same base station105or by different base stations105. The wireless communications system100may include, for example, a heterogeneous LTE/LTE-A/LTE-A Pro or NR network in which different types of base stations105provide coverage for various geographic coverage areas.

UEs115may be dispersed throughout the wireless communications system100, and each UE115may be stationary or mobile. A UE115may also be referred to as a mobile device, a wireless device, a remote device, a handheld device, or a subscriber device, or some other suitable terminology, where the “device” may also be referred to as a unit, a station, a terminal, or a client. A UE115may also be a personal electronic device such as a cellular phone (UE115a-d), a personal digital assistant (PDA), a wearable device (UE115h), a tablet computer, a laptop computer, or a personal computer. In some examples, a UE115may also refer to a wireless local loop (WLL) station, an Internet-of-things (IoT) device (115g), an Internet-of-everything (IoE) device, an MTC device, or the like, which may be implemented in various articles such as appliances, vehicles (UE115eand UE115i-k), meters (UE115f), or the like.

Base stations105may communicate with the core network and with one another. For example, base stations105may interface with the core network through backhaul links (e.g., via an S1, N2, N3, or other interface). Base stations105may communicate with one another over backhaul links (e.g., via an X2, Xn, or other interface) either directly (e.g., directly between base stations105) or indirectly (e.g., via core network).

Wireless communications system100may include operations by different network operating entities (e.g., network operators), in which each network operator may share spectrum. In some instances, a network operating entity may be configured to use an entirety of a designated shared spectrum for at least a period of time before another network operating entity uses the entirety of the designated shared spectrum for a different period of time. Thus, in order to allow network operating entities use of the full designated shared spectrum, and in order to mitigate interfering communications between the different network operating entities, certain resources (e.g., time) may be partitioned and allocated to the different network operating entities for certain types of communication.

For example, a network operating entity may be allocated certain time resources reserved for exclusive communication by the network operating entity using the entirety of the shared spectrum. The network operating entity may also be allocated other time resources where the entity is given priority over other network operating entities to communicate using the shared spectrum. These time resources, prioritized for use by the network operating entity, may be utilized by other network operating entities on an opportunistic basis if the prioritized network operating entity does not utilize the resources. Additional time resources may be allocated for any network operator to use on an opportunistic basis.

Access to the shared spectrum and the arbitration of time resources among different network operating entities may be centrally controlled by a separate entity, autonomously determined by a predefined arbitration scheme, or dynamically determined based on interactions between wireless nodes of the network operators.

In various implementations, wireless communications system100may use both licensed and unlicensed radio frequency spectrum bands. For example, wireless communications system100may employ license assisted access (LAA), LTE-unlicensed (LTE-U) radio access technology, or NR technology in an unlicensed band (NR-U), such as the 5 GHz ISM band. In some cases, UE115and base station105of the wireless communications system100may operate in a shared radio frequency spectrum band, which may include licensed or unlicensed (e.g., contention-based) frequency spectrum. In an unlicensed frequency portion of the shared radio frequency spectrum band, UEs115or base stations105may traditionally perform a medium-sensing procedure to contend for access to the frequency spectrum. For example, UE115or base station105may perform a listen before talk (LBT) procedure such as a clear channel assessment (CCA) prior to communicating in order to determine whether the shared channel is available.

A CCA may include an energy detection procedure to determine whether there are any other active transmissions on the shared channel. For example, a device may infer that a change in a received signal strength indicator (RSSI) of a power meter indicates that a channel is occupied. Specifically, signal power that is concentrated in a certain bandwidth and exceeds a predetermined noise floor may indicate another wireless transmitter. A CCA also may include message detection of specific sequences that indicate use of the channel. For example, another device may transmit a specific preamble prior to transmitting a data sequence. In some cases, an LBT procedure may include a wireless node adjusting its own backoff window based on the amount of energy detected on a channel and/or the acknowledge/negative-acknowledge (ACK/NACK) feedback for its own transmitted packets as a proxy for collisions.

In general, four categories of LBT procedure have been suggested for sensing a shared channel for signals that may indicate the channel is already occupied. In a first category (CAT 1 LBT), no LBT or CCA is applied to detect occupancy of the shared channel. A second category (CAT 2 LBT), which may also be referred to as an abbreviated LBT, a single-shot LBT, 16-μs or a 25-μs LBT, provides for the node to perform a CCA to detect energy above a predetermined threshold or detect a message or preamble occupying the shared channel. The CAT 2 LBT performs the CCA without using a random back-off operation, which results in its abbreviated length, relative to the next categories.

A third category (CAT 3 LBT) performs CCA to detect energy or messages on a shared channel, but also uses a random back-off and fixed contention window. Therefore, when the node initiates the CAT 3 LBT, it performs a first CCA to detect occupancy of the shared channel. If the shared channel is idle for the duration of the first CCA, the node may proceed to transmit. However, if the first CCA detects a signal occupying the shared channel, the node selects a random back-off based on the fixed contention window size and performs an extended CCA. If the shared channel is detected to be idle during the extended CCA and the random number has been decremented to 0, then the node may begin transmission on the shared channel. Otherwise, the node decrements the random number and performs another extended CCA. The node would continue performing extended CCA until the random number reaches 0. If the random number reaches 0 without any of the extended CCAs detecting channel occupancy, the node may then transmit on the shared channel. If at any of the extended CCA, the node detects channel occupancy, the node may re-select a new random back-off based on the fixed contention window size to begin the countdown again.

A fourth category (CAT 4 LBT), which may also be referred to as a full LBT procedure, performs the CCA with energy or message detection using a random back-off and variable contention window size. The sequence of CCA detection proceeds similarly to the process of the CAT 3 LBT, except that the contention window size is variable for the CAT 4 LBT procedure.

Sensing for shared channel access may also be categorized into either full-blown or abbreviated types of LBT procedures. For example, a full LBT procedure, such as a CAT 3 or CAT 4 LBT procedure, including extended channel clearance assessment (ECCA) over a non-trivial number of 9-μs slots, may also be referred to as a “Type 1 LBT.” An abbreviated LBT procedure, such as a CAT 2 LBT procedure, which may include a one-shot CCA for 16-μs or 25-μs, may also be referred to as a “Type 2 LBT.”

Use of a medium-sensing procedure to contend for access to an unlicensed shared spectrum may result in communication inefficiencies. This may be particularly evident when multiple network operating entities (e.g., network operators) are attempting to access a shared resource. In wireless communications system100, base stations105and UEs115may be operated by the same or different network operating entities. In some examples, an individual base station105or UE115may be operated by more than one network operating entity. In other examples, each base station105and UE115may be operated by a single network operating entity. Requiring each base station105and UE115of different network operating entities to contend for shared resources may result in increased signaling overhead and communication latency.

In some cases, operations in unlicensed bands may be based on a carrier aggregation configuration in conjunction with component carriers operating in a licensed band (e.g., LAA). Operations in unlicensed spectrum may include downlink transmissions, uplink transmissions, peer-to-peer transmissions, or a combination of these. Duplexing in unlicensed spectrum may be based on frequency division duplexing (FDD), time division duplexing (TDD), or a combination of both.

The term “carrier,” as may be used herein, refers to a set of radio frequency spectrum resources having a defined physical layer structure for supporting communications over a communication link. For example, a carrier of a communication link may include a portion of a radio frequency spectrum band that is operated according to physical layer channels for a given radio access technology. Each physical layer channel may carry user data, control information, or other signaling. A carrier may be associated with a predefined frequency channel (e.g., an evolved universal mobile telecommunication system terrestrial radio access (E-UTRA) absolute radio frequency channel number (EARFCN)), and may be positioned according to a channel raster for discovery by UEs115. Carriers may be downlink or uplink (e.g., in an FDD mode), or be configured to carry downlink and uplink communications (e.g., in a TDD mode). In some examples, signal waveforms transmitted over a carrier may be made up of multiple sub-carriers (e.g., using multi-NRF carrier modulation (MCM) techniques such as orthogonal frequency division multiplexing (OFDM) or discrete Fourier transform spread OFDM (DFT-S-OFDM)).

In some cases, wireless communications system100may utilize enhanced component carriers (eCCs). An eCC may be characterized by one or more features including wider carrier or frequency channel bandwidth, shorter symbol duration, shorter TTI duration, or modified control channel configuration. In certain instances, an eCC may be associated with a carrier aggregation configuration or a dual connectivity configuration (e.g., when multiple serving cells have a suboptimal or non-ideal backhaul link). An eCC may also be configured for use in unlicensed spectrum or shared spectrum (e.g., where more than one operator is allowed to use the spectrum, such as NR-shared spectrum (NR-SS)). An eCC characterized by wide carrier bandwidth may include one or more segments that may be utilized by UEs115that are not capable of monitoring the whole carrier bandwidth or are otherwise configured to use a limited carrier bandwidth (e.g., to conserve power).

FIG.2shows a block diagram of a design of a base station105and a UE115, which may be one of the base station and one of the UEs inFIG.1. At base station105, a transmit processor220may receive data from a data source212and control information from a controller/processor240. The control information may be for the PBCH, PCFICH, PHICH, PDCCH, EPDCCH, MPDCCH etc. The data may be for the PDSCH, etc. The transmit processor220may process (e.g., encode and symbol map) the data and control information to obtain data symbols and control symbols, respectively. The transmit processor220may also generate reference symbols, e.g., for the PSS, SSS, and cell-specific reference signal. A transmit (TX) multiple-input multiple-output (MIMO) processor230may perform spatial processing (e.g., precoding) on the data symbols, the control symbols, and/or the reference symbols, if applicable, and may provide output symbol streams to the modulators (MODs)232athrough232t. Each modulator232may process a respective output symbol stream (e.g., for OFDM, etc.) to obtain an output sample stream. Each modulator232may further process (e.g., convert to analog, amplify, filter, and upconvert) the output sample stream to obtain a downlink signal. Downlink signals from modulators232athrough232tmay be transmitted via the antennas234athrough234t, respectively.

At UE115, the antennas252athrough252rmay receive the downlink signals from the base station105and may provide received signals to the demodulators (DEMODs)254athrough254r, respectively. Each demodulator254may condition (e.g., filter, amplify, downconvert, and digitize) a respective received signal to obtain input samples. Each demodulator254may further process the input samples (e.g., for OFDM, etc.) to obtain received symbols. A MIMO detector256may obtain received symbols from all the demodulators254athrough254r, perform MIMO detection on the received symbols if applicable, and provide detected symbols. A receive processor258may process (e.g., demodulate, deinterleave, and decode) the detected symbols, provide decoded data for the UE115to a data sink260, and provide decoded control information to a controller/processor280.

On the uplink, at the UE115, a transmit processor264may receive and process data (e.g., for the PUSCH) from a data source262and control information (e.g., for the PUCCH) from the controller/processor280. The transmit processor264may also generate reference symbols for a reference signal. The symbols from the transmit processor264may be precoded by a TX MIMO processor266if applicable, further processed by the modulators254athrough254r(e.g., for SC-FDM, etc.), and transmitted to the base station105. At the base station105, the uplink signals from the UE115may be received by the antennas234, processed by the demodulators232, detected by a MIMO detector236if applicable, and further processed by a receive processor238to obtain decoded data and control information sent by the UE115. The processor238may provide the decoded data to a data sink239and the decoded control information to the controller/processor240.

The controllers/processors240and280may direct the operation at the base station105and the UE115, respectively. The controller/processor240and/or other processors and modules at the base station105may perform or direct the execution of various processes for the techniques described herein. The controllers/processor280and/or other processors and modules at the UE115may also perform or direct the execution of the functional blocks illustrated inFIGS.1-8and/or other processes for the techniques described herein. The memories242and282may store data and program codes for the base station105and the UE115, respectively. A scheduler244may schedule UEs for data transmission on the downlink and/or uplink.

In current wireless communication systems, a user equipment (UE) may be configured to provide feedback (e.g., hybrid automatic repeat request (HARQ) feedback (e.g., acknowledgement (ACK)/non-ACK (HACK))) for a PDSCH transmission in a particular feedback resource of a PUCCH. In some implementations, the UE may be configured (e.g., by downlink control message) to provide HARQ feedback for multiple PDSCH transmissions in the same PUCCH HARQ resource. In this case, the UE may multiplex the HARQ feedback bits corresponding to the multiple PDSCH transmissions into a single transmission. This multiplexing is referred as HARQ feedback codebook (CB) generation. In these cases, a HARQ feedback CB may be generated that includes the multiplexed bits representing the HARQ feedback for the multiple PDSCH transmissions. The size of the HARQ feedback CB may be based on the number of bits (e.g., the number of HARQ feedback bits each associated with a HARQ feedback for a respective PDSCH transmission) included in the HARQ feedback CB.

In implementations, generating and/or constructing a HARQ-ACK CB may be performed using one of two types of methods. A Type 1 CB generation (also known as a semi-static CB generation) may include a HARQ-ACK CB being generated based on semi-static information (e.g., information configured via radio resource control (RRC)). In a Type 2 CB generation (also known as dynamic CB generation), the HARQ-ACK CB may be constructed based on indications in a downlink control information (DCI) message (e.g., may be based on a downlink assignment index (DAI) in the DCI).

In some implementations, HARQ feedback may be slot-based, in which there may be a single PUCCH transmission within a slot that may carry HARQ feedback. In these implementations, if multiple HARQ feedback bits are to be transmitted within a slot, these HARQ feedback bits are multiplexed and transmitted in the single PUCCH transmission. However, this may cause latency issues as there is no mechanism for scheduling retransmissions within a slot, as a single feedback transmission is available.

In other implementations, sub-slot based HARQ feedback reporting is supported for low latency communications. In these implementations, a regular slot (e.g., a slot with typically 14 OFDM symbols) may be split into multiple sub-slots (e.g., of varying sizes), and a UE may transmit a HARQ-ACK transmission within each of the multiple sub-slots, thereby being configured to transmit multiple HARQ feedback transmissions within a slot. In these implementations, a UE may be configured for sub-slot based HARQ feedback reporting via a sub-slot length parameter (e.g., a subslotLengthForPUCCH parameter), which may specify the length of a sub-slot within a slot, and may typically specify a two-symbol or seven-symbol sub-slot length for normal cyclic prefix (CP) configurations, and/or a two-symbol or six-symbol sub-slot length for extended CP configurations.

In some current implementations, only Type-2 HARQ-ACK CB generation is supported. Type 1 HARQ-ACK CB generation has been proposed to be supported in future implementations of wireless communication systems. Current proposals for implementing HARQ-ACK CB generation include supporting Type-1 HARQ-ACK codebook for sub-slot based PUCCH configuration. In consideration, it is noted that the properties of the Type-1 HARQ-ACK codebook for sub-slot PUCCH at least include that a PDSCH time domain resource allocation (TDRA) be associated with an uplink (UL) (e.g., PUCCH) sub-slot if the end of the PDSCH overlaps with the associated sub-slot determined by a k1 value in a set of sub-slot timing values K1. However, there are currently no mechanisms for determining whether to group PDSCH TDRA per DL slot or per sub-slot. It is noted that, in aspects, the set of K1 values may be configured to the UE (e.g., by a network entity via a control message, such as in an uplink transmission grant) and may be used by the UE to determine a resource (e.g., an uplink resource) for providing ACK/NACK feedback associated with the uplink transmission grant.

FIGS.3A and3Bare diagrams illustrating an example of a type 1 HARQ feedback codebook generation. In particular,FIG.3Ais a diagram illustrating an example of slot configuration300supporting type 1 HARQ feedback codebook generation. UE115may be configured (e.g., via RRC), for each slot, with a set of parameters specifying a configuration for the slot, including one or more TDRAs for the slot. A TDRA represents a potential allocation in which a base station (e.g., base station105) may schedule and/or transmit a PDSCH to UE115. For example, slot310may be configured with seven TDRAs320-326. Each TDRA may be defined by a starting symbol S, and a length L. For example, TDRA320of length 12 symbols may be configured to start at symbol 2 of slot310, while TDRA324of length 4 symbols may be configured to start at symbol 3 of slot310. Base station105may schedule a PDSCH transmission to be received by UE115in any of TDRAs320-326. In aspects, base station105may transmit at least one PDSCH to UE115by dynamically indicating (e.g., via a DCI in a transmission grant) the TDRAs in which base station105is to transmit a PDSCH, and UE115may receive the PDSCH transmission in the indicated TDRAs.

In some implementations, a PDSCH transmission may not overlap with another PDSCH transmission within the same slot. Therefore, base station105may transmit multiple PDSCH transmissions in TDRAs that do not overlap with each other (and/or with another TDRA). In this manner, the number of PDSCH reception occasions within a slot (e.g., the number PDSCH transmission that may be scheduled within a slot) may be less than the number of TDRAs configured for a slot. For example, in slot310, at most two non-overlapping PDSCH transmissions may be scheduled. As can be seen, TDRA324and TDRA325are non-overlapping, and TDRA324and TDRA326are also non-overlapping. As such, within the configuration of slot310of UE115, base station105may transmit at most two non-overlapping PDSCH transmissions, a PDSCH in TDRA324and another PDSCH in TDRA325, or a PDSCH in TDRA324and another PDSCH in TDRA326. Any other PDSCH transmission within slot310may overlap with another PDSCH transmission and thus may not be allowed.

In implementations, generating a Type 1 HARQ feedback CB may involve enumerating all TDRAs configured within a slot, determining a number of PDSCH transmissions that may be scheduled within the slot based on the TDRAs (e.g., the number of non-overlapping PDSCH reception occasions within a slot), and then generating an amount of HARQ feedback bits based on the number of non-overlapping PDSCH reception occasions. UE115may then assign the different HARQ feedback bits to the non-overlapping TDRAs. For example, UE115may determine, after enumerating TDRAs320-326, that at most there are two non-overlapping PDSCH reception occasions available within slot310(e.g., in TDRA324and TDRA325, or in TDRA324and TDRA326). UE115may generate two HARQ-feedback bits. Base station105may then map each of TDRA324and TDRA325, or each of TDRA324and TDRA326, to a corresponding HARQ feedback bit. For example, TDRA324may be mapped to the first bit, and either TDRA325or TDRA326may be mapped to the second bit.

It is noted that TDRA pruning may also be referred to as TDRA grouping. In implementations, TDRA pruning may include grouping subsets of the TDRAs into groups and then mapping the groups to a HARQ feedback bit. For example, as shown inFIG.3A, TDRAs320-324may be grouped together and mapped to the first bit, and TDRA325and TDRA326may be grouped together and mapped to the second bit. Generally, the TDRAs within a group may be overlapping TDRAs. In these cases, at most one TDRA from the subset may be used at a given time to schedule a PDSCH from the base station. In the standard specifications defining operations of current wireless communication systems (e.g., 3GPP specifications), pseudo code may be defined to determine the number of bits, and to map each TDRA candidate to a HARQ-ACK bit, as described above.

It is also noted that the above procedure may also be referred to as TDRA pruning, as the set of configured TDRAs in a slot is pruned to determine the maximum number of non-overlapping PDSCH reception occasions within a slot.

It is further noted that withFIGS.3A and3B, and throughout the current disclosure, the examples described may specify that one HARQ feedback bit may be generated for each PDSCH occasion without loss of generality. However, it will be appreciated that the techniques described herein may be equally applicable to other scenarios in which a UE may generate more than one HARQ feedback bit per PDSCH occasion. In particular, in another example, the number of HARQ feedback bits may be twice the number of PDSCH occasions when, for each PDSCH occasion, a PDSCH occasion is configured to have at most two transport blocks (TBs), and the UE may feedback one bit per TB in a PDSCH occasion. In another example implementing code-block group (CBG), the number of HARQ feedback bits may be M times the number of PDSCH occasions, where M is the configured CBG size. In these examples, the UE may feedback M bits (for the M configured CBGs) for each PDSCH occasion.

The next steps in the Type 1 HARQ feedback CB generation may include determining a number of, and which, HARQ feedback bits are to be multiplexed within the HARQ feedback to be transmitted to base station105. As noted above, within slot310, at most, two HARQ feedback bits may be generated. However, the HARQ feedback CB may include the HARQ feedback bits from slot310, as well as HARQ feedback bits from other slots.FIG.3Bis a diagram illustrating an example of a Type 1 HARQ feedback CB generation. In particular, when determining the size of the HARQ feedback CB to be transmitted to base station105in a HARQ feedback slot, UE115may be configured to determine the slots in which a PDSCH for which a HARQ feedback is to be transmitted in the HARQ feedback slot, and then to multiplex the HARQ feedback for the various PDSCH transmissions in the determined slots. For example, when configuring UE115to receive a PDSCH transmission (e.g., in a DCI) within a slot, base station105may specify a k1 value that is to be used for determining a slot in which HARQ feedback for the PDSCH transmission is to be transmitted to base station105. In aspects, the k1 values may be semi-statically configured, and UE115may be configured with a K1 set of k1 values, and base station105may indicate (e.g., via the DCI message) which k1 value from the K1 set UE115is to use to transmit a HARQ feedback for a PDSCH. For example, base station105may schedule to transmit a PDSCH in slot n−1, and may indicate a k1=3. In this case, UE115may transmit a HARQ feedback for the PDSCH transmission received in slot n−1 in slot (n−1)+3=n+2.

Based on the foregoing, UE115may be configured to consider all values in the K1 set when determining for which slots to include HARQ feedback in the HARQ feedback CB. For example, a K1 set in the example illustrated inFIG.3Bmay include K1={2,3}. In this case, UE115may be configured to determine to transmit a Type 1 HARQ feedback CB in slot n+2. UE115may construct the Type 1 HARQ feedback CB by determining slots for which to include HARQ feedback in the HARQ feedback CB. In this case, UE115may “look back” from slot n+2 to slots based on the K1 set. For example, UE115may look back to slot (n+2)−2=n, and may perform the above procedures (e.g., the TDRA pruning procedure) to determine a number of HARQ feedback bits for slot n. In this manner, UE115may determine the maximum number of HARQ feedback bits that may be added for slot n to the HARQ feedback CB to be transmitted in slot n+2. UE115may also look back to slot (n+2)−3=n−1, and may perform the above procedures (e.g., the TDRA pruning procedure) to determine a number of HARQ feedback bits for slot n−1. In this manner, UE115may determine the maximum number of HARQ feedback bits that may be added for slot n−1 to the HARQ feedback CB to be transmitted in slot n+2. UE115may perform this process for all values in the K1 set and in this manner may determine a size of a semi-static Type 1 HARQ feedback CB to be transmitted in slot n+2. UE115may multiplex the HARQ feedback bits from the various slots into the HARQ feedback CB.

It should be noted from the above, that the size of a semi-static HARQ feedback CB may depend on two parameters, namely the set of TDRAs candidates (which may determine the number of HARQ feedback bits for a given slot) and the set of K1 values (which may determine which slot's HARQ feedback may be multiplexed into the HARQ feedback CB).

In some cases, Type 1 HARQ feedback CB generation is a straightforward procedure, especially when the DL and uplink (UL) have the same numerology and/or subcarrier spacing (SCS) (e.g., when the same slot-length is used for the DL slots and UL slots). In this case, when UE115looks back (e.g., based on the K1 set of values) to determine for which slots the HARQ feedback is to be multiplexed into the HARQ feedback CB, the look back is based on a number of UL slots. For example, with reference toFIG.3B, when UE115looks back from slot n+2, UE115looks back 2 and 3 uplink slot lengths (based on K1={2,3}) to DL slots n and n−1, respectively. This is because the length of a DL and UL slot is the same. UE115may then perform TDRA pruning on DL slots n and n−1 to determine a size of the HARQ feedback CB.

However, when the DL SCS is greater than the UL SCS, then one UL slot may contain more than one DL slot (e.g., the duration of one UL slot may overlap, or include, the duration of more than one DL slot), as the UL slots may have longer lengths.FIG.4is a diagram illustrating an example of a configuration in which a UL slot is longer than a downlink slot. In particular, as shown, each of UL slot has a length that overlaps the length of more than one DL slot. For example, UL slot410may overlap downlink slots420and421, UL slot411may overlap downlink slots422and downlink slot 4, and UL slot413may overlap downlink slots423and downlink slot 6. In this case, for a HARQ feedback CB to be transmitted in slot413, UE115may enumerate UL slots determined based on the set of K1 values (which in this example is K1={1,2,3} to enumerate UL slot410(e.g., based on k1=3), UL slot411(e.g., based on k1=2), and UL slot412(e.g., based on k1=1). For each enumerated UL slot, UE115may determine to perform TDRA pruning on the corresponding DL slots (e.g., the slots contained within the UL slot) to determine the number of HARQ feedback bits for each of the DL slots. For example, for k1=3, UE115may determine to enumerate UL slot410. UE115may then perform TDRA pruning on DL slots420and421. The same procedure may be applied for all enumerated UL slots and corresponding DL slots.

When the DL SCS is less than the UL SCS, then one DL slot may contain more than one UL slot (e.g., the duration of one DL slot may overlap, or include, the duration of more than one UL slot), as the DL slots may have longer lengths.FIG.5is a diagram illustrating an example of a configuration in which a DL slot is longer than an UL slot. In particular, as shown, each DL slot430and431may have a length that overlaps the length of more than one UL slot. For example, DL slot430may overlap UL slots440and441, and DL slot431may overlap UL slots442and443. In this case, for a HARQ feedback CB to be transmitted in slot443, determining which UL slots may be enumerated and which DL slots may be TDRA pruned may include applying a special rule. In some implementations, the special rule may specify that the TDRA pruning procedure described above may be performed on a subset of the UL slots determined by the set K1 of k1 values. This special rule is described in the following.

Under the special rule, the k1 value is applied always in terms of number of UL slots. In this case, the UL numerology is followed. For example, for K1={1,2,3}, UE115may enumerate UL slot440(e.g., based on k1=3), UL slot441(e.g., based on k1=2), and UL slot442(e.g., based on k1=1). In these cases, for a HARQ feedback CB to be reported in a PUCCH in UL slot nU(e.g., slot443), UE115may perform TDRA pruning on DL slots corresponding to (e.g., including or overlapping) enumerated UL slots nU−k1, with k1 values that satisfy the condition mod(nv−k1+1,NULDL)=0, where NULDLrepresents the number of UL slots in a DL slot (e.g., 2 in the example shown inFIG.5). In this case, conditioning the performance of the TDRA pruning procedure on the above condition may facilitate avoiding double-counting PDSCH reception occasion candidates in a DL slot. For example, PDSCH occasions may be determined every other UL slot when one DL slot=two UL slots (as in the example shownFIG.5), or PDSCH occasions may be determined every fourth UL slot when one DL slot=four UL slots, etc. When the condition above is satisfied, UE115may perform TDRA pruning within the corresponding DL slot of the UL slot.

In the example shown inFIG.5, with K1={1,2,3}, and with PUCCH carrying the HARQ feedback CB being transmitted in UL slot 2n+3, UE115may perform TDRA pruning on the DL slot corresponding to UL slot441(e.g., UL slot 2n+1), namely DL slot430. It is noted that TDRA pruning is performed per DL slot.

Although current approaches support a case in which a UL slot length is not equal to the DL slot length, this current support is limited to the case in which either one UL slot is a multiple of DL slots, or one DL slot is a multiple of UL slots. However, there is currently no mechanism to support the case in which there is a partial overlapping between UL and DL slots (e.g., when a UL slot is not fully contained within a single DL slot, or when a DL slot is not fully contained within a single UL slot). In addition, current implementations that check whether the condition of a k1 value satisfy mod(nv−k1+1,NULDL)=0 may not allow a UE to transmit HARQ feedback in every slot, thereby incurring unnecessary latency. Furthermore, the current approach has a large redundancy when the UL slots are not aligned with DL slots (e.g., when DL slot is longer than UL slot and a UL slot is not contained completely within a DL slot). In this case, the UE may insert dummy UL slots to align with a DL slot.

Various aspects of the present disclosure are directed to systems and methods for supporting sub-slot based Type-1 HARQ feedback codebook generation. In aspects, techniques are provided for constructing and/or generating a set of candidate PDSCH reception occasions for an active bandwidth part (BWP) of a DL serving cell that may be used for generating a HARQ feedback CB, and which may address the problems with the current approaches mentioned above, and which may be effective for both mixed numerology and arbitrary UL sub-slot configuration.

In particular aspects, a UE determines to generate a HARQ feedback CB to be transmitted to a base station in a particular UL sub-slot of a plurality of UL sub-slots of an UL slot. In aspects, the UE obtains a set of UL sub-slots based, at least in part, on the feedback UL sub-slot and a set of K1 values. In these aspects, each UL sub-slot in the set of UL sub-slots corresponds to a different k1 value of the set of K1 values. The UE then iterates, or loop, through the k1 values of the set of K1 values, e.g., in descending order or ascending order, to determine whether each UL sub-slot in the set of UL sub-NRF slots overlaps with a DL slot. In aspects, the UE also iterates through all DL slots that overlap any of the UL sub-slots in the set of UL sub-slots. For example, for a first UL sub-slot in the set of UL sub-slots, a determination is made as to whether the first UL sub-slot overlaps a first DL slot. In this case, while the first DL slot overlaps the first UL sub-slot, a determination is made as to whether a predetermined overlapping condition between the first UL sub-slot and the first DL slot is met. In aspects, the predetermined overlapping condition between the first UL sub-slot and the first DL slot includes whether the first UL sub-slot is the last UL sub-slot (e.g., the UL sub-slot with the highest index) in the set of UL sub-slots that overlaps with the first DL slot. Alternatively, the predetermined overlapping condition between the first UL sub-slot and the first DL slot includes whether the first UL sub-slot is the last UL sub-slot in the set of UL sub-slots that ends within the first DL slot. In aspects, the same procedure is used to determine whether any of the UL sub-slots in the set of UL sub-slots satisfies the overlapping condition with any of the DL slots overlapping any of the UL sub-slots in the set of UL sub-slots.

In aspects, when the predetermined overlapping condition between the first UL sub-slot and the first DL slot is determined to be met, the UE performs a procedure for determining a set of candidate PDSCH reception occasions in the first DL slot, where the procedure includes removing TDRA candidates from the set of TDRA candidates with which the first DL slot is configured when the TDRA candidates end in a symbol that does not fall within any (or falls outside all) of the UL sub-slots in the set of UL sub-slots. In some aspects, the set of TDRA candidates of the first DL slot is further trimmed by removing TDRA candidates that overlap with a semi-static UL symbol, and removing TDRA candidates that overlap with other TDRA candidates within the first DL slot (e.g., legacy TDRA pruning). The remaining set of TDRA candidates is used to generate the set of candidate PDSCH reception occasions in the first DL slot. In aspects, the set of candidate PDSCH reception occasions in the first DL slot is added to the set of candidate PDSCH reception occasions in other DL slots that overlaps with UL sub-slots in the set of UL sub-slots to generate the set of candidate PDSCH reception occasions from which the HARQ feedback CB s to be generated.

In aspects, the UE generates or construct the HARQ feedback CB based on the overall set of PDSCH reception occasions. In some aspects, the HARQ feedback CB includes one or more HARQ feedback bit for each candidate PDSCH reception occasion in the set of candidate PDSCH reception occasions, as described above. As will be appreciated, generating the HARQ feedback CB based on the overall set of PDSCH reception occasions provides a HARQ feedback CB technique that addresses the problems with current approaches for HARQ feedback codebook generation (e.g., UL/DL lengths not a multiple of each other, a UE not allowed to transmit HARQ feedback in every slot due to condition check, large redundancy due to UL/DL misalignment, etc.), as it considers whether the overlapping condition is present when determining on which DL slots and/or UL sub-slots the procedure for determining a set of candidate PDSCH reception occasions is to be performed, even if there is a UL/DL slot misalignment, partial overlap, or a condition check, on the DL/UL slots.

FIG.6is a block diagram illustrating example blocks executed to implement one aspect of the present disclosure. The example blocks will also be described with respect to UE115as illustrated inFIG.8.FIG.8is a block diagram illustrating UE115configured according to one aspect of the present disclosure. UE115includes the structure, hardware, and components as illustrated for UE115ofFIG.2. For example, UE115includes controller/processor280, which operates to execute logic or computer instructions stored in memory282, as well as controlling the components of UE115that provide the features and functionality of UE115. UE115, under control of controller/processor280, transmits and receives signals via wireless radios801a-rand antennas252a-r. Wireless radios801a-rincludes various components and hardware, as illustrated inFIG.2for UE115, including modulator/demodulators254a-r, MIMO detector256, receive processor258, transmit processor264, and TX MIMO processor266.

In addition, the example blocks will also be described with respect to the diagram illustrated inFIG.7Aand the diagram illustrated inFIG.7B.FIG.7Ais a diagram illustrating an example of a DL slot configuration including TDRA candidates in accordance aspects of the present disclosure. In particular,FIG.7Ashows DL slot configuration700, which specifies a number of TDRA candidates in which base station105may schedule PDSCH transmission to UE115. In aspects, the set of TDRA candidates may be determined by UE115based on prior configuration of UE115or may be indicated by base station105to UE115. In the particular example illustrated inFIG.7A, DL slot configuration700may specify six TDRAs710-715with which a DL slot for UE115may be configured. As seen, the DL slot may include 14 symbols. In this example, TDRA candidate710may occupy the first two symbols, TDRA candidate711may occupy symbols 1-13, TDRA candidate712may occupy symbols 0-3, TDRA candidate713may occupy symbols 2-5, TDRA candidate714may occupy symbols 8 and 9, and TDRA candidate715may occupy symbols 8-13.

FIG.7Bis a diagram illustrating an example of a sub-slot based Type-1 HARQ feedback codebook generation in accordance with aspects of the present disclosure. In particular,FIG.7Bshows a configuration for UE115in which UL slot760may include 14 symbols, and may be configured with an SCS=15 KHz and a sub-slot length=2 symbols. In this example, UL slot760may include seven sub-slots 0-6. In this example, DL slots750and751(also referred to herein as slot 0 and slot 1, respectively) may each be configured to include 14 symbols, but may be configured with an SCS=30 KHz, in which case, each UL symbol of UL slot760overlaps two DL symbols of DL slots750and751(e.g., the duration of one UL symbol is equal to the aggregated duration of two DL symbols). In this example, UL slot760may overlap both downlink slots750and751. In this example, UE115may be configured with a set of K1={2, 3, 4, 5}.

At block600, a UE (e.g., UE115) determines to generate a feedback CB (e.g., a HARQ feedback CB) to be transmitted to a base station (e.g., base station105) in an UL sub-slot of a plurality of UL sub-slots of an UL slot. In order to implement the functionality for such operations, UE115, under control of controller/processor280, executes feedback generation logic802, stored in memory282. The functionality implemented through the execution environment of feedback generation logic802allows for UE115to perform feedback CB generation operations according to the various aspects herein. For example, UE115may determine to transmit a HARQ feedback CB in UL sub-slot 6 of UL slot760.

At block601, UE115obtains a set of UL sub-slots based, at least in part, on the UL sub-slot in which the HARQ feedback CB is to be transmitted and a set of K1 values. In order to implement the functionality for such operations, UE115, under control of controller/processor280, executes K1 UL sub-slots set generator803, stored in memory282. The functionality implemented through the execution environment of K1 UL sub-slots set generator803allows for UE115to perform operations for obtaining and/or generating the set of UL sub-slots based, at least in part, on the UL sub-slot in which the HARQ feedback CB is to be transmitted and the set of K1 values according to the various aspects herein. In aspects, each of the UL sub-slots in the set of UL sub-slots may be determined by a corresponding K1 value of the set of K1 values, with respect to the UL sub-slot in which the HARQ feedback CB is to be transmitted. For example, for the set of K1={2, 3, 4, 5}, UE115may determine a set of UL sub-slots that may include UL sub-slot 4 (corresponding to k1=2 based on sub-slot 6−2=sub-slot 4), UL sub-slot 3 (corresponding to k1=3 based on sub-slot 6−3=sub-slot 3), UL sub-slot 2 (corresponding to k1=4 based on sub-slot 6−4=sub-slot 2), UL sub-slot 1 (corresponding to k1=5 based on sub-slot 6−1=sub-slot 1). In this example, the set of UL sub-slots may include {UL sub-slot 1, UL sub-slot 2, UL sub-slot 3, UL sub-slot 4}.

At block602, UE115determines, for each UL sub-slot in the set of UL sub-slots, whether a current UL sub-slot in the set of UL sub-slots satisfies a predetermined overlapping condition with a current DL slot. It is noted that as used herein, a current DL slot and/or a current UL sub-slot may refer to a current DL slot and/or a current UL sub-slot in terms of the iterative loop. As such, a current DL slot and/or a current UL sub-slot may refer to a DL slot and/or an UL sub-slot that is currently being processed in the iterative process or loop. Similarly, a next DL slot and/or a next UL sub-slot may refer to a DL slot and/or a UL sub-slot that is to be processed next, such as in the next iteration, in the iterative process or loop. In order to implement the functionality for such operations, UE115, under control of controller/processor280, executes overlap determination manager804, stored in memory282. The functionality implemented through the execution environment of overlap determination manager804allows for UE115to perform operations for determining whether a current UL sub-slot in the set of UL sub-slots satisfies a predetermined overlapping condition with a current DL slot according to the various aspects herein. In aspects, the current UL sub-slot may be associated with one of the k1 values in the set K1, and UE115may loop through all of the k1 values in the set K1 values in a descending or ascending order. In aspects, the current DL slot configured with a set of time domain resource allocation (TDRA) candidates. In aspects, determining whether the current UL sub-slot satisfies the predetermined overlapping condition with the current DL slot includes determining whether the current UL sub-slot in the set of UL sub-slots overlaps with the current DL slot. In this manner, the determination of whether a current UL sub-slot overlaps with a current DL slot may be part of a loop associated with all the configured k1 values of set K1. For example, UE115may loop through the k1 values in K1={2, 3, 4, 5} in descending or ascending order, beginning with k1=5, which may correspond to UL sub-slot 1, and may determine whether a current DL slot (e.g., DL slot 0) overlaps with UL sub-slot 1. In particular, it is noted that aspects of the present disclosure also provide functionality to loop through DL slots that overlap any of the UL sub-slots of the set of UL sub-slots in the process for determining a set of PDSCH reception candidates for which the HARQ feedback CB is to be generated. For example, aspects provide functionality to loop (e.g., the outer while loop in the pseudo-code illustrated in Table 1) through each UL sub-slot. Then, through another loop (e.g., the inner while loop in the pseudo-code illustrated in Table 1) a current UL sub-slot may be fixed and the process loops through DL slots that may overlap with the current UL sub-slot (e.g., instead of the DL slots that overlap with any UL sub-slot in the set of UL sub-slots). In aspects, the other DL slots may be considered once the outer while loop moves to another UL sub-slot that overlaps with these other DL slots.

In aspects, determining whether the current UL sub-slot satisfies the predetermined overlapping condition with the current DL slot may include UE115determining whether the current UL sub-slot in the set of UL sub-slots satisfies the predetermined overlapping condition with the current DL slot while the current UL sub-slot in the set of UL sub-slots overlaps with the current DL slot. For example, UE115may determine, while DL slot 0 overlaps with UL sub-slot 1, whether UL sub-slot 1 satisfies the predetermined overlapping condition with DL slot 0. In aspects, the predetermined overlapping condition between DL slot 0 and UL sub-slot 1 may include whether UL sub-slot 1 is the last UL sub-slot in the set of UL sub-slots that overlaps with DL slot 0. Alternatively, the predetermined overlapping condition between the DL slot 0 and UL sub-slot 1 may include whether UL sub-slot 1 is the last UL sub-slot in the set of UL sub-slots that ends within the duration of DL slot 0. In this case, UL sub-slot 1 is not the last UL sub-slot in the set of UL sub-slots {UL sub-slot 1, UL sub-slot 2, UL sub-slot 3, UL sub-slot 4} that overlaps DL slot 0, as UL sub-slot 2 and UL sub-slot 3 both overlap DL slot 0 and occur later in the set of UL sub-slots. Alternatively, UL sub-slot 1 is not the last UL sub-slot in the set of UL sub-slots that ends within DL slot 0, as UL sub-slot 2 also ends within DL slot 0 and occurs later in the set of UL sub-slots. Therefore, in this example, UL sub-slot 1 does not satisfy the predetermined overlapping condition with DL slot 0.

In aspects, as UL sub-slot 1 does not satisfy the predetermined overlapping condition with DL slot 0, UE115may not consider UL sub-slot 1 (e.g., may skip UL sub-slot 1) for performing a TDRA determination (e.g., generating a set of candidate PDSCH reception occasions) for the associated DL slot (e.g., DL slot 0) based on UL sub-slot 1. In this case, UE115may increment the DL slot index, which may proceed to the next DL slot, e.g., DL slot 1. In aspects, UE115may determine whether DL slot 1 and UL sub-slot 1 overlap. As DL slot 1 and UL sub-slot 1 do not overlap, UE115may reset the DL slot counter (back to DL slot 0) and may increment the UL sub-slot counter to proceed to the next k1 value in the K1 set (e.g., k1=4) in descending or ascending order. In this case, the next UL sub-slot corresponding to k1=4 may be UL sub-slot 2.

In aspects, UE115may apply the same procedure as described above to UL sub-slot 2. In these aspects, UE115may determine, while DL slot 0 overlaps with UL sub-slot 2, whether UL sub-slot 2 satisfies the predetermined overlapping condition with DL slot 0. In this case, UL sub-slot 2 is not the last UL sub-slot in the set of UL sub-slots that overlaps DL slot 0, as UL sub-slot 3 overlaps DL slot 0 and occurs later in the set of UL sub-slots. Based on this condition, UL sub-slot 2 does not satisfy the predetermined overlapping condition with DL slot 0, and UE115may not consider UL sub-slot 2 (e.g., may skip UL sub-slot 2) for performing a TDRA determination (e.g., generating a set of candidate PDSCH reception occasions) for DL slot 0 based on UL sub-slot 2.

However, in alternative aspects as noted above, the predetermined overlapping condition may include determining whether UL sub-slot 2 is the last UL sub-slot in the set of UL sub-slots that ends within the duration of DL slot 0. In this example, UL sub-slot 2 is the last UL sub-slot in the set of UL sub-slots that ends within DL slot 0, as the next UL sub-slot (e.g., UL sub-slot 3) does not end within DL slot 0. In these aspects, and based on UL sub-slot 2 satisfying the predetermined overlapping condition with DL slot 0, UE115may perform a TDRA determination (e.g., to generate a set of candidate PDSCH reception occasions) for DL slot 0. Details of the procedure for generating a set of candidate PDSCH reception occasions for a DL slot will be discussed in more detail below.

In aspects, UE115may again increment the DL slot index, which may proceed to the next DL slot, e.g., DL slot 1, and may determine that DL slot 1 and UL sub-slot 2 do not overlap. UE115may reset the DL slot counter (back to DL slot 0) and may increment the UL sub-slot counter to proceed to the next k1 value in the K1 set (e.g., k1=3) in descending or ascending order. In this case, the next UL sub-slot corresponding to k1=3 may be UL sub-slot 3.

In aspects, UE115may apply the same procedure as described above to UL sub-slot 3. In particular, UE115may determine, while DL slot 0 overlaps with UL sub-slot 3, whether UL sub-slot 3 satisfies the predetermined overlapping condition with DL slot 0. In this case, UL sub-slot 3 is the last UL sub-slot in the set of UL sub-slots that overlaps DL slot 0. Based on this condition, UL sub-slot 3 satisfies the predetermined overlapping condition with DL slot 0, and UE115may consider UL sub-slot 3 (e.g., may not skip UL sub-slot 3) for performing a TDRA determination (e.g., generating a set of candidate PDSCH reception occasions) for DL slot 0 based on UL sub-slot 3.

It is noted that, DL slot 0 may not be processed to generate a set of candidate PDSCH reception occasions based on UL sub-slots 1 and 2, when the first option for the predetermined overlapping condition (e.g., whether the UL sub-slot is the last UL sub-slot in the set of UL sub-slots overlapping with DL slot 0) is used, but DL slot 0 may be processed to generate a set of candidate PDSCH reception occasions based on UL sub-slots 3. On the other hand, DL slot 0 may not be processed to generate a set of candidate PDSCH reception occasions based on UL sub-slots 1 and 3, when the second option for the predetermined overlapping condition (e.g., whether the UL sub-slot is the last UL sub-slot in the set of UL sub-slots ending within DL slot 0) is used, but DL slot 0 may be processed to generate a set of candidate PDSCH reception occasions based on UL sub-slot 2.

In aspects, UE115may again increment the DL slot index, which may proceed to the next DL slot, e.g., DL slot 1, and may determine that DL slot 1 and UL sub-slot 3 do overlap. In this case, UE115may apply the same procedure as described above to UL sub-slot 3 with respect to DL slot 1. In particular, UE115may determine, while DL slot 1 overlaps with UL sub-slot 3, whether UL sub-slot 3 satisfies the predetermined overlapping condition with DL slot 1. In this case, UL sub-slot 3 is not the last UL sub-slot in the set of UL sub-slots that overlaps DL slot 1, as UL sub-slot 4 also overlaps with DL slot 1 and occurs later in the set of UL sub-slots. Based on this, UE115may determine that UL sub-slot 3 does not satisfy the predetermined overlapping condition with DL slot 1. Alternatively, UE115may determine that UL sub-slot 3 is not the last UL sub-slot in the set of UL sub-slots that ends within DL slot 1, as UL sub-slot 4 also ends within DL slot 1 and occurs later in the set of UL sub-slots. Therefore, under this alternative, UE115may determine that UL sub-slot 3 does not satisfy the predetermined overlapping condition with DL slot 1. Therefore, UE115may not consider UL sub-slot 3 (e.g., may skip UL sub-slot 3) for performing a TDRA determination (e.g., generating a set of candidate PDSCH reception occasions) for DL slot 1 based on UL sub-slot 3.

UE115may reset the DL slot counter (back to DL slot 0) and may increment the UL sub-slot counter to proceed to the next k1 value in the K1 set (e.g., k1=2) in descending or ascending order. In this case, the next UL sub-slot corresponding to k1=2 may be UL sub-slot 4.

In aspects, UE115may apply the same procedure as described above to UL sub-slot 4. In particular, UE115may determine, while DL slot 1 overlaps with UL sub-slot 4, whether UL sub-slot 4 satisfies the predetermined overlapping condition with DL slot 1. In this case, UL sub-slot 4 is the last UL sub-slot in the set of UL sub-slots that overlaps DL slot 1. Based on this condition, UL sub-slot 4 satisfies the predetermined overlapping condition with DL slot 1, and UE115may consider UL sub-slot 4 (e.g., may not skip UL sub-slot 4) for performing a TDRA determination (e.g., generating a set of candidate PDSCH reception occasions) for DL slot 1 based on UL sub-slot 4.

Alternatively, the predetermined overlapping condition may include determining whether UL sub-slot 4 is the last UL sub-slot in the set of UL sub-slots that ends within the duration of DL slot 1. In this example, UL sub-slot 4 is the last UL sub-slot in the set of UL sub-slots that ends within DL slot 1. In these aspects, and based on UL sub-slot 4 satisfying the predetermined overlapping condition with DL slot 1, UE115may perform a TDRA determination (e.g., to generate a set of candidate PDSCH reception occasions) for DL slot 1. Details of the procedure for generating a set of candidate PDSCH reception occasions for a DL slot will be discussed in more detail below.

It is noted that, DL slot 1 may not be processed to generate a set of candidate PDSCH reception occasions based on UL sub-slot 3, when either the first option for the predetermined overlapping condition (e.g., whether the UL sub-slot is the last UL sub-slot in the set of UL sub-slots overlapping with DL slot 0) is used, or when the second option for the predetermined overlapping condition (e.g., whether the UL sub-slot is the last UL sub-slot in the set of UL sub-slots ending within DL slot 0) is used. However, when either option is used, DL slot 1 may be processed to generate a set of candidate PDSCH reception occasions based on UL sub-slot 4, as UL sub-slot 4 meets either condition.

At block603, UE115generates a set of PDSCH reception occasions based, at least in part, on the set of TDRA candidates of the current DL slot and a determination that the current DL slot satisfies the predetermined overlapping condition with the current UL sub-slot, or that the current UL sub-slot satisfies the predetermined overlapping condition with the current DL slot. In order to implement the functionality for such operations, UE115, under control of controller/processor280, executes PDSCH occasions set manager805, stored in memory282. The functionality implemented through the execution environment of PDSCH occasions set manager805allows for UE115to perform operations for generating a set of PDSCH reception occasions based, at least in part, on the set of TDRA candidates of the current DL slot and a determination that the current DL slot satisfies the predetermined overlapping condition with the current UL sub-slot, or that the current UL sub-slot satisfies the predetermined overlapping condition with the current DL slot according to the various aspects herein.

At block604UE115constructs the HARQ feedback CB based on the set of PDSCH reception occasions. In aspects, constructing the HARQ feedback CB based on the set of PDSCH reception occasions includes including a feedback bit for each candidate PDSCH reception occasion in the set of PDSCH reception occasions in the HARQ feedback CB.

In aspects, the above procedure for generating a set of candidate PDSCH reception occasions, based, at least in part, on the set of TDRA candidates of the current DL slot and a determination that the current DL slot satisfies the predetermined overlapping condition with the current UL sub-slot, or that the current UL sub-slot satisfies the predetermined overlapping condition with the current DL slot, from which a HARQ feedback CB is generated may be implemented using the pseudo code illustrated in Table 1 below. It should be appreciated that the pseudo code is provided for illustrative purposes and should not be construed as limiting the present disclosure in any way. It should also be appreciated that the above described techniques may be implemented using different pseudo code and/or program code.

TABLE 1Pseudo-code to construct a set of candidate PDSCH receptionoccasions for the active BWP of a DL serving cell in accordancewith aspects of the present disclosure.Let nUbe the UL sub-slot index in which the HARQ feedback CB isto be transmitted.Let S = {nU− K1,k:k = 0, . . ., |K1| − 1} be the set of UL sub-slotsdetermined by the set of RRC configured slot timing values K1− (Smay also be referred to as HARQ feedback window (in UL sub-slots),and K1may be RRC configured (e.g., via dl-DataToUL-ACK).)Set k = 0 − (index of slot timing values {K1,k} (in the unit of ULsub-slots), in descending or ascending order of the slot timing values,in set K1for serving cell c.)While k < |K1|—(loop over all configured values in K1(in unit of ULsub-slots) in descending or ascending order, represent cardinality)>Set nD= 0—(index of a DL slot that overlaps with the ULsub-slot nU− K1,k)>While DL slot nDoverlaps with UL sub-slot nU− K1,k>>if UL sub-slot nU− K1,kis the last UL sub-slot in S that overlapswith DL slot nD(or alternatively if it the last UL sub-slot in S that endsin DL slot nD), and>>if there is NO UL active BWP change or DL active BWP changebetween DL slot nDand UL sub-slot nU>>>Perform candidate PDSCH reception occasions generationprocedure to determine a set B of candidate PDSCH reception occasionsin DL slot nD.>>>MA,C= MA,CuB, where MA,C2is the set of candidatePDSCH reception occasions from which the HARQ feedback CB is tobe generated>>End if>>nD= nD+ 1>End while>k = k + 1End while

In aspects, as seen in the pseudo-code illustrated in Table 1, the predetermined overlapping condition may also include a determination as to whether, between an UL sub-slot nUand a DL slot nD, there is one or more of a UL BWP change or a DL BWP change. In these cases, the UE may omit the corresponding DL slot nDfor PDSCH reception occasion generation.

In aspects, generating the set of PDSCH reception occasions from which the HARQ feedback CB is generated may include multiplexing HARQ feedback bits for each PDSCH reception occasion in the set of candidate PDSCH reception occasions for each DL slot that was determined for TDRA determination based on the above described procedure. For example, DL slot 0 and DL slot 1 are both identified for TDRA determinations based on the predetermined overlapping condition being satisfied with at least one associated UL sub-slot in the set of UL sub-slots. In aspects, a set of candidate PDSCH reception occasions for DL slot 0 may be determined, and a set of candidate PDSCH reception occasions for DL slot 1 may also be determined. UE115may generate the set of PDSCH reception occasions from which the HARQ feedback CB is generated based on the set of candidate PDSCH reception occasions for DL slot 0 and the set of candidate PDSCH reception occasions for DL slot 1. In some aspects, UE115may generate a HARQ feedback bit for each candidate PDSCH reception occasion in the set of candidate PDSCH reception occasions.

In aspects, performing the TDRA determination for a DL slot may include applying a candidate PDSCH reception occasions generation procedure. In aspects, the candidate PDSCH reception occasions generation procedure for a particular slot may include, for each TDRA candidate r in the set R of RRC configured TDRA candidates in a DL slot, first removing all TDRA candidates r from set R that at least conflict with one semi-static UL symbol. For example, for DL slot 0 and DL slot 1 with DL slot configuration700(as shown inFIG.7A), the set R may include TDRA candidates710-715. In this example, it may be assumed that no TDRA candidate r in the set R conflicts with a semi-static UL symbol of UL slot760for either DL slot 0 and DL slot 1. As such, in this example, no TDRA candidate may be removed from the set R that includes TDRA candidates710-715for DL slot 0 or DL slot 1. Therefore, after the first step of the candidate PDSCH reception occasions generation procedure, the set of TDRA candidates for DL slot 0 includes TDRA candidates710-715, and the set of TDRA candidates for DL slot 1 includes TDRA candidates710-715.

Next in the candidate PDSCH reception occasions generation procedure, UE115may remove a TDRA candidate r in the set R when the TDRA candidate r ends in a symbol that falls outside of all, or does not fall in any of the, UL sub-slots in the set of UL sub-slots. For example, given the set of UL sub-slots {UL sub-slot 1, UL sub-slot 2, UL sub-slot 3, UL sub-slot 4} as determined above, and with respect to DL slot 0, UL sub-slot 1 overlaps with symbols 4-7 of DL slot 0. As seen inFIG.7A, only TDRA713ends in a symbol that falls within UL sub-slot 1, namely symbol 5 of DL slot 0. In this same example, UL sub-slot 2 overlaps with symbols 8-11 of DL slot 0. As seen inFIG.7A, only TDRA714ends in a symbol that falls within UL sub-slot 2, namely symbol 9 of DL slot 0. UL sub-slot 3 overlaps with symbols 12 and 13 of DL slot 0 (and also with symbols 0 and 1 of DL slot 1). As seen inFIG.7A, TDRAs711and715end in a symbol that falls within UL sub-slot 3, namely symbol 13 of DL slot 0. In this case, with respect to DL slot 0, TDRAs713,714,711, and715are kept in the set of TDRA candidates, but TDRAs710and712are removed. Therefore, after the second step of the candidate PDSCH reception occasions generation procedure, the set of TDRA candidates for DL slot 0 includes TDRA candidates711and713-715.

With respect to slot 1, UL sub-slot 3 overlaps with symbols 0 and 1 of DL slot 1. As seen inFIG.7A, only TDRA710ends in a symbol that falls within UL sub-slot 3, namely symbol 1 of DL slot 1. UL sub-slot 4 overlaps with symbols 2-5 of DL slot 1. As seen inFIG.7A, TDRAs712and713end in a symbol that falls within UL sub-slot 4, namely symbols 3 and 5 of DL slot 1. In this case, with respect to DL slot 1, TDRAs710,712, and713are kept in the set of TDRA candidates, but TDRAs711,714, and715are removed. Therefore, after the second step of the candidate PDSCH reception occasions generation procedure, the set of TDRA candidates for DL slot 1 includes TDRA710,712, and713.

Next in the candidate PDSCH reception occasions generation procedure, UE115may perform TDRA pruning, or TDRA grouping, as described above. In this step, UE115may determine a set of PDSCH reception occasions for DL slot 0 by applying TDRA pruning to TDRA candidates711and713-715. Applying TDRA pruning to TDRA candidates711and713-715may generate two HARQ feedback bits, as at most there may be 2 non-overlapping PDSCH reception occasions between TDRA candidates711and713-715. UE115may determine a set of PDSCH reception occasions for DL slot 1 by applying TDRA pruning to TDRA candidates710,712, and713. Applying TDRA pruning to TDRA candidates710,712, and713may generate two HARQ feedback bits, as at most there may be 2 non-overlapping PDSCH reception occasions between TDRA candidates710,712, and713.

Based on the above candidate PDSCH reception occasions generation procedure on DL slots 0 and 1, UE115may generate a HARQ feedback CB that includes four HARQ feedback bits (e.g., two HARQ feedback bits for DL slot 0 and two HARQ feedback bits for DL slot 1).

FIGS.7C and7Dare diagrams illustrating an example of a sub-slot based Type 1 HARQ feedback CB generation in accordance with aspects of the present disclosure.FIG.7Cis a diagram illustrating an example of a DL slot configuration including TDRA candidates in accordance aspects of the present disclosure. In particular,FIG.7Cshows DL slot configuration720, which specifies six TDRA candidates730-735in which base station may schedule PDSCH transmission to UE115. As shown, DL slot configuration720may include 14 symbols.

FIG.7Dis a diagram illustrating an example of a sub-slot based Type-1 HARQ feedback codebook generation in accordance with aspects of the present disclosure. In particular,FIG.7Dshows a configuration for UE115in which UL slots780and781may each include 14 symbols, and may be configured with an SCS=15 KHz and a sub-slot length=7 symbols. In this example, each of UL slot780and781may include two sub-slots 0 and 1. In this example, DL slots770and771may each be configured to include 14 symbols, but may be configured with an SCS=15 KHz, which is the same SCS as UL slots780and781(e.g., the duration of one UL symbol is equal to the duration of one DL symbol). In this example, one UL slot may overlap one DL slot. In this example, UE115may be configured with a set of K1={1, 2}.

In aspects, UE115may be configured to transmit a HARQ feedback CB in sub-slot 1 of UL slot781. Applying the techniques disclosed herein may include determining a set S of UL sub-slots based on K1={1, 2}. This yields a set {UL sub-slot 0 of UL slot781associated with k1=1, UL sub-slot 1 of UL slot780associated with k1=2}. Iterating or looping through the set K1={1, 2} in descending or ascending order and through DL slots780and781, for UL sub-slot 1 of UL slot780, it may be determined that a predetermined overlapping condition as described above is met between UL sub-slot 1 of UL slot780and DL slot770. In response, a candidate PDSCH reception occasions generation procedure may be applied to DL slot770as described above. Applying the candidate PDSCH reception occasions generation procedure, and assuming no DL symbols of DL slot770overlaps a semi-static symbol, may yield a set of TDRA candidates that include TDRAs730,731,734, and735, as these TDRAs end in a symbol within UL sub-slot 1 of UL slot780. As there are no non-overlapping TDRAs in the set of TDRAs730,731,734, and735, at most one PDSCH reception occasion may be scheduled for this set and therefore one HARQ feedback bit is generated for DL slot770. With respect to UL sub-slot 0 of UL slot781it may be determined that a predetermined overlapping condition as described above is met between UL sub-slot 0 of UL slot781and DL slot771. In response, a candidate PDSCH reception occasions generation procedure may be applied to DL slot771as described above. Applying the candidate PDSCH reception occasions generation procedure, and assuming no DL symbols of DL slot771overlap a semi-static symbol, may yield a set of TDRA candidates that include TDRAs732and733, as these TDRAs end in a symbol within UL sub-slot 0 of UL slot781. As there are no non-overlapping TDRAs in the set of TDRAs732and733, at most one PDSCH reception occasion may be scheduled for this set and therefore one HARQ feedback bit is generated for DL slot771.

Based on the above candidate PDSCH reception occasions generation procedure on DL slots770and771, UE115may generate a HARQ feedback CB that includes two HARQ feedback bits (e.g., one HARQ feedback bit for DL slot770and one HARQ feedback bit for DL slot771) to be transmitted in sub-slot 1 of UL slot781.

In one or more aspects, techniques for supporting sub-slot based Type-1 HARQ feedback codebook generation in a wireless communication system according to one or more aspects includes additional aspects, such as any single aspect or any combination of aspects described below or in connection with one or more other processes or devices described elsewhere herein. In a first aspect, supporting sub-slot based Type-1 HARQ feedback codebook generation in a wireless communication system includes an apparatus configured to determine to generate a feedback codebook to be transmitted to a base station in a feedback UL sub-slot of a plurality of UL sub-slots of an UL slot, to obtain a set of UL sub-slots based, at least in part, on the feedback UL sub-slot and a set of K1 values, each UL sub-slot in the set of UL sub-slots associated with a different K1 value of the set of K1 values, to determine, for each UL sub-slot in the set of UL sub-slots, whether a current UL sub-slot in the set of UL sub-slots satisfies a predetermined overlapping condition with a current DL slot, the current DL slot configured with a set of TDRA candidates, to generate a set of PDSCH reception occasions based, at least in part, on the set of TDRA candidates of the current DL slot and a determination that the current UL sub-slot satisfies the predetermined overlapping condition with the current DL slot, and to construct the feedback codebook based on the set of PDSCH reception occasions. Additionally, the apparatus performs or operate according to one or more aspects as described below. In some implementations, the apparatus includes a wireless device, such as a UE. In some implementations, the apparatus includes at least one processor, and a memory coupled to the processor. The processor is configured to perform operations described herein with respect to the apparatus. In some other implementations, the apparatus includes a non-transitory computer-readable medium having program code recorded thereon and the program code is executable by a computer for causing the computer to perform operations described herein with reference to the apparatus. In some implementations, the apparatus includes one or more means configured to perform operations described herein. In some implementations, a method of wireless communication includes one or more operations described herein with reference to the apparatus.

In a second aspect, alone or in combination with the first aspect, determining whether the current UL sub-slot satisfies the predetermined overlapping condition with the current DL slot includes determining whether the current UL sub-slot in the set of UL sub-slots overlaps with the current DL slot.

In a third aspect, alone or in combination with one or more of the first aspect or the second aspect, determining whether the current UL sub-slot satisfies the predetermined overlapping condition with the current DL slot includes determining whether the current UL sub-slot is the last UL sub-slot in the set of UL sub-slots that overlaps with the current DL slot.

In a fourth aspect, alone or in combination with one or more of the first aspect through the third aspect, determining whether the current UL sub-slot satisfies the predetermined overlapping condition with the current DL slot includes determining whether the current UL sub-slot is the last UL sub-slot in the set of UL sub-slots that ends within the current DL slot.

In a fifth aspect, alone or in combination with one or more of the first aspect through the fourth aspect, determining, for each UL sub-slot in the set of UL sub-slots, whether the current UL sub-slot in the set of UL sub-slots satisfies a predetermined overlapping condition includes determining, for each UL sub-slot in a descending order in the set of UL sub-slots, whether the current UL sub-slot in the set of UL sub-slots satisfies a predetermined overlapping condition.

In a sixth aspect, alone or in combination with one or more of the first aspect through the fifth aspect, wherein the feedback codebook includes one or more feedback bits for each candidate PDSCH reception occasion in the set of PDSCH reception occasions.

In a seventh aspect, alone or in combination with one or more of the first aspect through the sixth aspect, generating the set of PDSCH reception occasions includes applying, in response to the determination that the current UL sub-slot satisfies the predetermined overlapping condition with the current DL slot, a candidate PDSCH reception occasions generation procedure.

In an eighth aspect, alone or in combination with the seventh aspect, the candidate PDSCH reception occasions generation procedure includes removing a TDRA candidate from the set of TDRA candidates of the current DL slot when the TDRA candidate ends in a symbol that falls outside of all UL sub-slots in the set of UL sub-slots to generate a trimmed set of TDRA candidates.

In a ninth aspect, alone or in combination with one or more of the seventh aspect through the eighth aspect, the candidate PDSCH reception occasions generation procedure includes generating the set of PDSCH reception occasions based, at least in part, on the trimmed set of TDRA candidates.

In a tenth aspect, alone or in combination with the seventh aspect, the candidate PDSCH reception occasions generation procedure includes removing a TDRA candidate from the set of TDRA candidates of the current DL slot when the TDRA candidate within the current DL slot conflicts with at least one semi-static UL symbol in at least one UL sub-slot of the plurality of UL sub-slots.

In an eleventh aspect, alone or in combination with the seventh aspect, the candidate PDSCH reception occasions generation procedure includes removing a TDRA candidate from the set of TDRA candidates of the current DL slot when the TDRA candidate overlaps with another TDRA candidate within the current DL slot.

In a twelfth aspect, alone or in combination with one or more of the first aspect through the eleventh aspect, the techniques of the first aspect include determining, whether a next UL sub-slot in the set of UL sub-slots satisfies the predetermined overlapping condition with the current DL slot, the next UL sub-slot associated with a K1 value that is less than a K1 value associated with the current UL sub-slot.

In a thirteenth aspect, alone or in combination with the twelfth aspect, when the next UL sub-slot satisfies the predetermined overlapping condition with the current DL slot, the current UL sub-slot does not satisfy the predetermined overlapping condition with the current DL slot.

In a fourteenth aspect, alone or in combination with one or more of the twelfth aspect through the thirteenth aspect, the techniques of the first aspect include generating the set of PDSCH reception occasions based, at least in part, on the set of TDRA candidates of the current DL slot when the next UL sub-slot satisfies the predetermined overlapping with the current DL slot.

In a fifteenth aspect, alone or in combination with one or more of the first aspect through the fourteenth aspect, the techniques of the first aspect include determining whether the current UL sub-slot in the set of UL sub-slots satisfies the predetermined overlapping condition with a next DL slot, the next DL slot having an index higher than the current DL slot.

In a sixteenth aspect, alone or in combination with the fifteenth aspect, the techniques of the first aspect include generating the set of PDSCH reception occasions based, at least in part, on a set of TDRA candidates configured for the next DL slot (e.g., a set of TDRA candidates for the next DL slot configured and/pr indicated to the UE), the set of TDRA candidates of the current DL slot, and a determination that the current UL sub-slot satisfies the predetermined overlapping condition with the next DL slot.

In a seventeenth aspect, alone or in combination with one or more of the first aspect through the sixteenth aspect, the techniques of the first aspect include determining whether a next UL sub-slot in the set of UL sub-slots satisfies the predetermined overlapping condition with a next DL slot, the next UL sub-slot associated with a K1 value that is less than a K1 value associated with the current UL sub-slot, the next DL slot having an index higher than the current DL slot.

In an eighteenth aspect, alone or in combination with the seventeenth aspect, when the next UL sub-slot satisfies the predetermined overlapping condition with the next DL slot, the current UL sub-slot does not satisfy the predetermined overlapping condition with the next DL slot.

In a nineteenth aspect, alone or in combination with one or more of the seventeenth aspect through the eighteenth aspect, the techniques of the first aspect include generating the set of PDSCH reception occasions based, at least in part, on a set of TDRA candidates of the next DL slot, the set of TDRA candidates of the current DL slot, and a determination that the next UL sub-slot satisfies the predetermined overlapping condition with the next DL slot.

In a twentieth aspect, alone or in combination with one or more of the first aspect through the nineteenth aspect, the duration of the UL slot is different than the duration of the current DL slot.