Patent ID: 12200722

DETAILED DESCRIPTION OF THE EMBODIMENTS

Long Term Evolution Advanced Radio Access Technology (4G)

FIG.1provides a schematic diagram illustrating some basic functionality of a mobile telecommunications network/system100operating generally in accordance with LTE principles, but which may also support other radio access technologies, and which may be adapted to implement embodiments of the disclosure as described herein. Various elements ofFIG.1and certain aspects of their respective modes of operation are well-known and defined in the relevant standards administered by the 3GPP® body, and also described in many books on the subject, for example, Holma H. and Toskala A [2]. It will be appreciated that operational aspects of the telecommunications networks discussed herein which are not specifically described (for example in relation to specific communication protocols and physical channels for communicating between different elements) may be implemented in accordance with any known techniques, for example according to the relevant standards and known proposed modifications and additions to the relevant standards.

The network100includes a plurality of base stations101connected to a core network part102. Each base station provides a coverage area103(e.g. a cell) within which data can be communicated to and from communications devices104. Data is transmitted from the base stations101to the communications devices104within their respective coverage areas103via a radio downlink. Data is transmitted from the communications devices104to the base stations101via a radio uplink. The core network part102routes data to and from the communications devices104via the respective base stations101and provides functions such as authentication, mobility management, charging and so on. Communications devices may also be referred to as mobile stations, user equipment (UE), user terminals, mobile radios, terminal devices, and so forth. Base stations, which are an example of network infrastructure equipment/network access nodes, may also be referred to as transceiver stations/nodeBs/e-nodeBs, g-nodeBs (gNB) and so forth. In this regard different terminology is often associated with different generations of wireless telecommunications systems for elements providing broadly comparable functionality. However, example embodiments of the disclosure may be equally implemented in different generations of wireless telecommunications systems such as 5G or new radio as explained below, and for simplicity certain terminology may be used regardless of the underlying network architecture. That is to say, the use of a specific term in relation to certain example implementations is not intended to indicate these implementations are limited to a certain generation of network that may be most associated with that particular terminology.

New Radio Access Technology (5G)

FIG.2is a schematic diagram illustrating a network architecture for a new Radio Access Technology (RAT) wireless communications network/system200based on previously proposed approaches which may also be adapted to provide functionality in accordance with embodiments of the disclosure described herein. The new RAT network200represented inFIG.2comprises a first communication cell201and a second communication cell202. Each communications cell201,202, comprises a controlling node (centralised unit)221,222in communication with a core network component210over a respective wired or wireless link251,252. The respective controlling nodes221,222are also each in communication with a plurality of distributed units (radio access nodes/remote transmission and reception points (TRPs))211,212in their respective cells. Again, these communications may be over respective wired or wireless links. The distributed units211,212are responsible for providing the radio access interface for communications devices connected to the network. Each distributed unit211,212has a coverage area (radio access footprint)241,242where the sum of the coverage areas of the distributed units under the control of a controlling node together define the coverage of the respective communication cells201,202. Each distributed unit211,212includes transceiver circuitry for transmission and reception of wireless signals and processor circuitry configured to control the respective distributed units211,212.

In terms of broad top-level functionality, the core network component210of the new RAT communications network represented inFIG.2may be broadly considered to correspond with the core network102represented inFIG.1, and the respective controlling nodes221,222and their associated distributed units/TRPs211,212may be broadly considered to provide functionality corresponding to the base stations101ofFIG.1. The term network infrastructure equipment/access node may be used to encompass these elements and more conventional base station type elements of wireless communications systems. Depending on the application at hand the responsibility for scheduling transmissions which are scheduled on the radio interface between the respective distributed units and the communications devices may lie with the controlling node/centralised unit and/or the distributed units/TRPs.

A communications device or UE260is represented inFIG.2within the coverage area of the first communication cell201. This communications device260may thus exchange signalling with the first controlling node221in the first communication cell via one of the distributed units211associated with the first communication cell201. In some cases communications for a given communications device are routed through only one of the distributed units, but it will be appreciated in some other implementations communications associated with a given communications device may be routed through more than one distributed unit, for example in a soft handover scenario and other scenarios.

In the example ofFIG.2, two communication cells201,202and one communications device260are shown for simplicity, but it will of course be appreciated that in practice the system may comprise a larger number of communication cells (each supported by a respective controlling node and plurality of distributed units) serving a larger number of communications devices.

It will further be appreciated thatFIG.2represents merely one example of a proposed architecture for a new RAT communications system in which approaches in accordance with the principles described herein may be adopted, and the functionality disclosed herein may also be applied in respect of wireless communications systems having different architectures.

Thus example embodiments of the disclosure as discussed herein may be implemented in wireless telecommunication systems/networks according to various different architectures, such as the example architectures shown inFIGS.1and2. It will thus be appreciated the specific wireless communications architecture in any given implementation is not of primary significance to the principles described herein. In this regard, example embodiments of the disclosure may be described generally in the context of communications between network infrastructure equipment/access nodes and a communications device, wherein the specific nature of the network infrastructure equipment/access node and the communications device will depend on the network infrastructure for the implementation at hand. For example, in some scenarios the network infrastructure equipment/access node may comprise a base station, such as an LTE-type base station101as shown inFIG.1which is adapted to provide functionality in accordance with the principles described herein, and in other examples the network infrastructure equipment/access node may comprise a control unit/controlling node221,222and/or a TRP211,212of the kind shown inFIG.2which is adapted to provide functionality in accordance with the principles described herein.

A more detailed illustration of a UE270and an example network infrastructure equipment272, which may be thought of as a gNB101or a combination of a controlling node221and TRP211, is presented inFIG.3. As shown inFIG.3, the UE270is shown to receive downlink data to the infrastructure equipment272via resources of a wireless access interface as illustrated generally by an arrow274. As withFIGS.1and2, the infrastructure equipment272is connected to a core network276via an interface278to a controller280of the infrastructure equipment272. The infrastructure equipment272includes a receiver282connected to an antenna284and a transmitter286connected to the antenna284. Correspondingly, the UE270includes a controller290connected to a receiver292which receives signals from an antenna294and a transmitter296also connected to the antenna294.

The controller280is configured to control the infrastructure equipment272and may comprise processor circuitry which may in turn comprise various sub-units/sub-circuits for providing functionality as explained further herein. These sub-units may be implemented as discrete hardware elements or as appropriately configured functions of the processor circuitry. Thus the controller280may comprise circuitry which is suitably configured/programmed to provide the desired functionality using conventional programming/configuration techniques for equipment in wireless telecommunications systems. The transmitter286and the receiver282may comprise signal processing and radio frequency filters, amplifiers and circuitry in accordance with conventional arrangements. The transmitter286, the receiver282and the controller280are schematically shown inFIG.3as separate elements for ease of representation. However, it will be appreciated that the functionality of these elements can be provided in various different ways, for example using one or more suitably programmed programmable computer(s), or one or more suitably configured application-specific integrated circuit(s)/circuitry/chip(s)/chipset(s). As will be appreciated the infrastructure equipment272will in general comprise various other elements associated with its operating functionality.

Correspondingly, the controller290of the UE270is configured to control the transmitter296and the receiver292and may comprise processor circuitry which may in turn comprise various sub-units/sub-circuits for providing functionality as explained further herein. These sub-units may be implemented as discrete hardware elements or as appropriately configured functions of the processor circuitry. Thus the controller290may comprise circuitry which is suitably configured/programmed to provide the desired functionality using conventional programming/configuration techniques for equipment in wireless telecommunications systems. Likewise, the transmitter296and the receiver292may comprise signal processing and radio frequency filters, amplifiers and circuitry in accordance with conventional arrangements. The transmitter296, receiver292and controller290are schematically shown inFIG.3as separate elements for ease of representation. However, it will be appreciated that the functionality of these elements can be provided in various different ways, for example using one or more suitably programmed programmable computer(s), or one or more suitably configured application-specific integrated circuit(s)/circuitry/chip(s)/chipset(s). As will be appreciated the communications device270will in general comprise various other elements associated with its operating functionality, for example a power source, user interface, and so forth, but these are not shown inFIG.3in the interests of simplicity.

5G, URLLC and Industrial Internet of Things

Systems incorporating NR technology are expected to support different services (or types of services), which may be characterised by different requirements for latency, data rate and/or reliability. For example, Enhanced Mobile Broadband (eMBB) services are characterised by high capacity with a requirement to support up to 20 Gb/s. The requirements for Ultra Reliable & Low Latency Communications (URLLC) [5] services are for a reliability of 1-10−5(99.999%) or higher for one transmission of a 32 byte packet with a user plane latency of 1 ms [3]. In some scenarios, there may be a requirement for a reliability of 1-10−6(99.9999%) or higher with either 0.5 ms or 1 ms of user plane latency. Massive Machine Type Communications (mMTC) is another example of a service which may be supported by NR-based communications networks.

In addition, systems may be expected to support further enhancements related to Industrial Internet of Things (IIoT) in order to support services with new requirements of high availability, high reliability, low latency, and in some cases, high-accuracy positioning.

Industrial automation, energy power distribution and intelligent transport systems are examples of new use cases for Industrial Internet of Things (IIoT). In an example of industrial automation, the system may involve different distributed components working together. These components may include sensors, virtualized hardware controllers and autonomous robots, which may be capable of initiating actions or reacting to critical events occurring within a factory and communicating over a local area network.

The UEs in the network may therefore be expected to handle a mixture of different traffic, for example, associated with different applications and potentially different quality of service requirements (such as maximum latency, reliability, packet sizes, throughput). Some messages for transmission may be time sensitive and be associated with strict deadlines and the communications network may therefore be required to provide time sensitive networking (TSN) [9].

URLLC services are required in order to meet the requirements for IIoT, which require high availability, high reliability, low latency, and in some cases, high-accuracy positioning [1]. Some IIoT services may be implemented by using a mixture of eMBB and URLLC techniques, where some data is transmitted by eMBB and other data is transmitted by URLLC. The mix of services being transmitted via the same wireless access interface can create new challenges for a wireless communications network which is configured to operate as efficiently as possible.

Embodiments of the present technique described below relate to transmitting HARQ feedback messages for downlink data at a communications device in accordance with an automatic repeated request-type protocol such as a Hybrid Automatic Repeat Request (HARQ) type protocol. A better appreciation of the following example embodiments can be gained from reviewing a proposed wireless access interface according to 3GPP LTE/4G and NR/5G. A wireless access interface in accordance with a 3GPP Standard for LTE is described in detail in Annex 1 in whichFIGS.17and18provide detailed representation of a wireless access interface for the downlink and the uplink respectively. More details of the LTE wireless access interface are therefore described in Annex 1. However it will be appreciated that the wireless access interface provides physical communications resources including shared channels for both uplink and the downlink which may be accessed by communicating appropriate control signalling as those acquainted with LTE will appreciate. Equally a wireless access interface for the 5G Standard as represented inFIG.2may be similarly formed in accordance with the arrangement shown in Annex 1 and may use OFDM on the downlink and OFDM or SC-FDMA on the uplink.

FIG.4provides a simplified representation of a downlink structure of a wireless access interface with time divided units which may be used for a NR wireless access interface structure. Whilst the terms “frames” and “sub-frames” used inFIG.4are terms which have been used in LTE, 3GPP standards adopted for 5G/NR may be different and so it will be appreciated thatFIG.4is provided for illustration only to assist in the explanation of the example embodiments. Current proposals for a time divided structure for 5G/NR include that one slot providing a time divided structure of the wireless access interface consists of 14 OFDM symbols304, and one sub-frame is defined by 1 ms. The term slot is used in this description to refer to a time slot or time divided unit and time slot and slot may be used interchangeably. As such, the time divided structure of the wireless access interface ofFIG.4shows an example in case of 30 kHz carrier spacing, so that one sub-frame301has two slots302.1,302.2and twenty eight symbols. As shown inFIG.4, the downlink of the wireless access interface is shown to comprise frames300with respect to which the UE270receives downlink data from the infrastructure equipment272. Consistent with the explanation provided in Annex 1, the downlink comprises in each frame300ten sub-frames301. A frame300is defined by 10 ms, a sub-frame301is defined by 1 ms, and a slot302is defined by fourteen OFDM symbols304, irrespective of subcarrier spacing. InFIG.4, 30 kHz subcarrier spacing is assumed. An expanded view of the components of a sub-frame301are shown to be formed from two consecutive slots n−1, n302.1,302.2, which include physical resources of a shared channel as well as control channels as explained in Annex 1 with reference toFIG.15.

Hybrid Automatic Repeat Request (HARQ) Feedback

Data may be transmitted by the communications device104, using uplink communications resources, or by the infrastructure equipment101, using downlink communications resources. Data may be transmitted within Medium Access Control (MAC) transport blocks. Each MAC transport block is constructed at the MAC protocol layer (such as, in the UE270, at the MAC protocol layer302).

Each MAC transport block may comprise, or be transmitted together with error check bits, which permit the receiver of the MAC transport block to determine whether the MAC transport block has been received and decoded without error (i.e. ‘correctly’ or ‘successfully’ received).

Improved data transmission reliability may be realised by the use of HARQ-acknowledgement (ACK) information (so-called HARQ feedback message or ACK/NACK) transmitted by the recipient of the data to the transmitter. The HARQ-ACK information may comprise an indication of an acknowledgement status for one or more portions of data. The acknowledgement status for a portion of data (such as data received in a given MAC TB) may indicate whether that data has/have been received in error, or has not been received at all.

In response to receiving the HARQ-ACK information, the data transmitter may retransmit data which has not been successfully received by the receiver. This process may be repeated as many times as necessary until all the data has been successfully conveyed to the intended recipient.

A HARQ process may operate ‘synchronously’ or ‘asynchronously’. According to a synchronous HARQ process, the relative timing of data transmission and the transmission of corresponding HARQ-ACK information is fixed according to predetermined parameters for the HARQ process.

A communications device may operate multiple HARQ processes in parallel, and these may be offset in time. For example, a data block associated with one HARQ process may be being received from the infrastructure equipment, a further data block may be being decoded to determine whether it has been received without error or not, and yet in respect of a further data block, acknowledgement information may have been recently transmitted to the infrastructure equipment and the communications device may be expecting to receive a retransmission of that further data block.

Embodiments of the present technique may find application in scenarios where the HARQ processes are synchronous or asynchronous.

In accordance with some conventional HARQ techniques, a retransmission of data may be encoded in a different manner to that used for a previous transmission of the same data. Additionally or alternatively, a receiver may store information (such as ‘soft bits’ generated as part of a decoding process) corresponding to an earlier transmission of the same data, and may use this information to improve the probability of successfully decoding the data after the subsequent retransmission.

In response to receiving data successfully or unsuccessfully (i.e. where it is determined that one or more errors are present) the corresponding acknowledgement status for that data may be updated. When HARQ-ACK information is subsequently generated for transmission, that HARQ-ACK information may take into account the updated acknowledgement status for that data.

According to various proposals, HARQ-ACK information may be generated and transmitted independently in respect of data associated with different services (or service types) and/or logical channels. For example, HARQ-ACK information relating to URLLC data may be generated and transmitted independently of HARQ-ACK information relating to eMBB data. In particular, uplink communications resources for the transmission of ACK data associated with different service types may be allocated independently.

A HARQ procedure may operate independently of the logical channels associated with the data being transmitted and acknowledged. For example, one transport block may carry data associated with multiple logical channels. A single acknowledgement status (ACK/NACK) may be determined for such a transport block.

Uplink communications resources for the transmission of acknowledgement information may occur less frequently than the transmission of downlink data. Therefore, there may arise a need for HARQ-ACK information transmitted using a given instance of uplink communications resources to convey the acknowledgement status corresponding to multiple downlink data transmissions and their respective MAC Transport Blocks.

Uplink communications resources for the transmission of acknowledgement information may be explicitly allocated by the infrastructure equipment. For example, downlink control information (DCI) indicating downlink communications resources for the transmission of downlink data may additionally comprise an indication of allocated uplink communications resources for the transmission of acknowledgement information.

Additionally or alternatively, the communications device104may determine uplink communications resources for transmitting acknowledgement information implicitly based on allocated downlink communications resources. Such uplink communications resources may be said to be ‘implicitly’ allocated.

FIG.5provides a part schematic part flow diagram illustrating operations performed by the UE270and the gNB272to communicate downlink data from the gNB to the UE in accordance with an HARQ process. As shown inFIG.5, the gNB272in the first process step S1transmits Downlink Control Information (DCI)292as represented by an arrow294to the UE270via a PDCCH. In process step S2the UE identifies from the DCI the communications resources of the downlink share channel (PDSCH) for receiving the downlink data from the gNB. The UE270also identifies from the DCI the uplink resources granted in the PUCCH for the UE to transmit an HARQ feedback message as an ACK/NACK for receiving the downlink data. In process step S4the gNB transmits a transport block in the granted PDSCH resources as represented by a block296and an arrow298. At process step S6the UE270then receives the transport block in the granted PDSCH resources, which were indicated by the DCI292. In process step S8the UE270determines whether the transport block296has been received correctly and transmits an ACK or NACK as an HARQ feedback message on the PUCCH resources granted by the gNB272identified from the DCI292. The UE270then transmits the ACK/NACK on the PUCCH as represented by a block299and an arrow291. In the process step2S10the gNB receives the HARQ feedback message as an ACK/NACK and at process step S12the gNB determines whether it should retransmit the transport block or not as represented by an arrow293. As can be seen fromFIG.5, the gNB provides an indication in the DCI292of the uplink resources of the PUCCH in which the HARQ ACK/NACK are to be transmitted. The following paragraphs provide a more detailed explanation of how the HARQ feedback messages are generated.

HARQ Codebook

The Downlink Control Information (DCI), which provides a grant of downlink resources (e.g. DCI format 1_0 and 1_1) for a Physical Downlink Shared Channel (PDSCH) also contains a PDSCH-to-HARQ_feedback field which indicates a time location of resource of the uplink in for example a PUCCH where a HARQ ACK/NACK feedback message corresponding to the Transport Block (TB) transmitted in the PDSCH is to be transmitted by the UE. The PDSCH-to-HARQ_feedback is a three bit indication in the DCI providing a K1value, where K1is a number of slots after the PDSCH transmission where the uplink resources of the PUCCH are provided for transmitting the ACK/NACK. Multiple PDSCHs can share a single PUCCH, i.e. the K1for each PDSCH points to the same slot and the HARQ feedback message for these PDSCHs are multiplexed into a single PUCCH using a HARQ codebook and are transmitted using the single PUCCH. The PDSCHs corresponding to the HARQ feedback messages that can be multiplexed in a HARQ codebook are within a time multiplexing window where the size of this codebook Multiplexing Window (Mux Window) is defined by a maximum K1value. It has been previously proposed to provide two types of HARQ “codebooks” for PDSCH HARQ feedback messages, which are known as Type 1 and Type 2 HARQ codebooks. A HARQ codebook is a list of possible codewords where each codeword is an encoded information bit representing a specific combination of ACK/NACKs. For example, a codebook for two HARQ feedback messages can have four ( ) combinations, i.e. {ACK, ACK}, {ACK, NACK}, {NACK, ACK} & {NACK, NACK}, each of these combinations can be encoded into a codeword which can be longer than 2 bits, e.g. a codeword=10101010 can represent {ACK, ACK} and another codeword=01010101 can represent {NACK, NACK}. These codewords can be selected such that they have large Hamming distances among them to reduce error cause by any of the bit in the codeword being wrong. The type 1 and type 2 HARQ codebooks will be explained in the following paragraphs:

Type 1 HARQ Codebook

A Type 1 HARQ codebook is a semi-static codebook where the number of HARQ ACK/NACKs feedbacks in the codebook is fixed. That is to say that the size of the codebook is configured using Radio Resource Control (RRC) signalling, and the size depends on the number of PDSCH occasions or PDSCH transmission opportunities within a given multiplexing window (Mux Window). An example is shown inFIG.6.

As shown inFIG.6, five slots302.1,302.2,302.3,302.4,302.5are shown of the downlink time divided structure303ofFIG.6with respect to five corresponding slots312.1.312.2,312.3,312.4,312.5of an uplink time divided structure315. In correspondence with the explanation given above with respect toFIG.5, the gNB transmits a DCI indicating a location in time and frequency of resources of the PDSCH where the gNB will transmit a transport block. As shown inFIG.6there are two DCIs320,322identified as DCI #1 and DCI #2, which point to two PDSCHs330,332identified as PDSCH #1, PDSCH #2 in time slots (slots)302.2,302.4as represented by the arrows340,342. The PDSCH transmission of TBs are within a Mux Window350of four time slots302.1,302.2,302.3,302.4. Each of these DCIs320,322also indicates communications resources in time and frequency where the UE270should transmit its HARQ feedback message in a PUCCH. As shown inFIG.6, the HARQ feedback message is provided in the fifth slot312.5of the uplink315, which is in PUCCH resources360indicated by each of the DCIs320,322as presented by arrows370,372.

As shown inFIG.6, a maximum K1value is four slots, which means that the Mux Window318is four slots and each slot contains a single PDSCH occasion or PDSCH transmission opportunity. At time t0in slot n, DCI #1320schedules PDSCH #1330in slot n+1302.2and the corresponding PUCCH360in slot n+4, i.e. K1=3. At time t2, slot n+1, another DCI322, DCI #2, is transmitted to the UE which schedules PDSCH #2332in slot n+3302.4and the corresponding PUCCH360in slot n+4, i.e. K1=1. Since PDSCH #1 and PDSCH #2330,332share the same PUCCH slot312.5, their HARQ feedback messages are multiplexed together so that they are transmitted using a single PUCCH360. In this example, the Type 1 HARQ codebook size is four where each entry corresponds to a PDSCH occasion, which provide four HARQ feedback messages, for each of slots {n, n+1, n+2, n+3}302.1,302.2,302.3,302.4. Since the codebook size is fixed, the PDSCH occasions that do not contain any scheduled PDSCH, i.e. in slot n and slot n+3 would indicate a NACK whilst those PDSCH occasions that has a scheduled PDSCH, i.e. slot n+1 and slot n+3, would indicate either an ACK or NACK depending on the decoding outcome of the PDSCH. In this example, it is assumed that the UE270decodes PDSCH #1 and PDSCH #2 successfully and hence the HARQ codebook would indicate {0101} (where 0=NACK and 1=ACK) for slots {n, n+1, n+2, n+3} respectfully.

Although effective, a Type 1 HARQ codebook is considered to be not resource efficient since the UE needs to provide a HARQ feedback message regardless whether any PDSCH is scheduled in a PDSCH occasion or not.

Type 2 HARQ Codebook

In contrast to the Type 1 HARQ codebook, the size of Type 2 HARQ codebook is dynamically determined. This is because an entry (for a HARQ feedback) in the codebook is only created if a PDSCH is scheduled. However, if the UE missed a downlink grant, it would not be unaware of the corresponding scheduled PDSCH and would therefore feedback a wrong HARQ codebook size (i.e. wrong number of HARQ feedbacks). Recognising this problem, a Downlink Assignment Index (DAI) field is used in the downlink grant to keep track of the number of the scheduled PDSCH, such that the UE is aware if it misses any intermediate downlink grants. An example of Type 2 HARQ codebook is shown inFIG.7, where corresponding reference numerals are used to those inFIG.6and only the differences will be described.

As shown inFIG.7, as withFIG.6the gNB transmits a DCI indicating a location in the time and frequency resources of the PDSCH where the gNB will transmit a transport block. However inFIG.7there are three DCIs420,422,444identified as DCI #1, DCI #2 and DCI #3, which point to three PDSCHs430,432,432identified as PDSCH #1, PDSCH #2 and PDSCH #3 in time slots302.2,302.3,302.4as represented by the arrows440,442,444. The PDSCH transmission of transport blocks are within a Mux Window350of four time slots302.1,302.2,302.3,302.4. Also as explained above, each of the DCIs420,422,424also indicates communications resources in time and frequency where the UE270should transmit its HARQ feedback message in a PUCCH. As shown inFIG.7, the HARQ feedback message is provided in the fifth slot312.5of the uplink315, which is in PUCCH resources460, which is indicated by each of the DCIs420,422,424as presented by arrows470,472,474.

As for the example ofFIG.6, inFIG.7again the Mux Window350is four slots302.1,302.2,302.3,302.4. For the example ofFIG.7, a DAI field of two bits {00, 01, 10, 11} is provided in each of the respective DCIs420,422,424. The DAI counter is circular, that is it revert back to 00 after four PDSCHs. In this example DCI #1, DCI #2 and DCI #3 schedules PDSCH #1 in slot n+1, PDSCH #2 in slot n+2 and PDSCH #3 in slot n+3302.2,302.3,302.4respectively, where all the HARQ feedback messages for these PDSCHs are multiplexed into a PUCCH460in slot n+4312.5. The DAI is increased for each scheduled PDSCH, that is, DCI #1 indicates a DAI=00 since it scheduled PDSCH #1, DCI #2 indicates a DAI=01 for PDSCH #2 and DCI #3 indicates a DAI=10 for PDSCH #3. In this example, the UE missed DCI #2 as represented by X480, i.e. it fails to detect the PDCCH carrying DCI #2 at time t2, however, at time t4, it receives DCI #3 which has a DAI=10. Since the last downlink grant was in DCI #1 which indicates a DAI=00, the UE270therefore is aware that it missed a downlink grant with a DAI=01. Assuming that the UE270successfully decoded PDSCH #1 and PDSCH #3, the UE270would multiplex three HARQ feedback messages in a codebook for the PUCCH460in slot n+4312.5where the HARQ codebook entries are {101}, i.e. an ACK for PDSCH #1, a NACK for the missed PDSCH #2 and another ACK for PDSCH #3.

PDSCH Occasions

A brief explanation will now be given of a structure of the DCIs shown inFIGS.7and8which has been proposed for New Radio (NR)/5G. This proposed format for a DCI uses a Time Domain Resource Assignment (TDRA) field to indicate time resources granted in the downlink for a PDSCH. The TDRA can be {0, 1, 2, 3, 4} bits and is an index to a lookup table where each entry in the lookup table contains the following information:K0: the number of slots relative to the slot containing the downlink grant (DCI) where the PDSCH is locatedS: the starting OFDM symbol of the PDSCH relative to the slot boundary (within the slot indicated in K0)L: the length of PDSCH in units of OFDM symbolsThe OFDM symbols containing DMRSThe PDSCH mapping, either Type A or Type B

An example describing the parameters K0, S and L is provided inFIG.8for the downlink frame structure ofFIGS.7and8. InFIG.8a DCI500transmitted in a PDCCH in a first time slot n302.1indicates a downlink grant of a PDSCH502with TDRA parameters are K0=2504, which indicates slot n+2302.3, S=7 OFDM symbols506and L=7 OFDM symbols508.

Each entry in the TDRA table is a potential PDSCH candidate and a PDSCH occasion is a time period where a single PDSCH candidate can be received by the UE. There can be multiple overlapping PDSCH candidates in a single PDSCH occasion. The PDSCH occasion is determined sequentially by first taking the TDRA entry with the earliest ending symbol m, and then group all TDRA entries where S≤m, i.e. all PDSCH candidates that starts before m are grouped into a PDSCH occasion. This is explained using an example two bit (four entries) TDRA table as in Table 1 below, where Demodulation Reference Symbols (DMRS) locations and PDSCH Mapping Type fields have been omitted.

TABLE 1Example TDRA table with 4 entriesTDRA IndexK0SL010141107217732311

FIG.9shows an example of four PDSCH candidates520,522,524,526which are indicated by a DCI512, with each being indicated with a corresponding TDRA entry in Table 1 above as TDRA #0, TDRA #1, TDRA #2, TDRA #3. These candidates520,522,524,526are then used by the UE to determine its PDSCH occasions. These may be determined using the following steps:1. The PDSCH candidate with the earliest ending symbol m1is TDRA #1, which ends in symbol 6 of slot n+1302.2(where n is the slot302.1containing the downlink grant)2. The entries where the starting symbol S≤m1(symbol 6 of slot n+1302.2) are {TDRA #0, TDRA #1}520,5223. These entries520,522are grouped by the UE {TDRA #0, TDRA #1} into PDSCH Occasion #1540, and these PDSCH candidates520,522are removed from the TDRA table4. The next PDSCH candidate524with the earliest ending symbol m2, belongs to TDRA #2, which ends in symbol 13 of slot n+1302.2.5. The PDSCH candidate with S≤m2(symbol 13 of slot n+1) is {TDRA #2}5246. The PDSCH candidate for TDRA #2 is grouped into PDSCH Occasion #2542and then removed from the TDRA table7. The PDSCH candidate identified for TDRA #3526is the only PDSCH candidate left and going through the steps will result in TDRA #3 being grouped into a PDSCH Occasion #3544

According to the above process performed by the UE and illustrated inFIG.9, three PDSCH occasions540,542,544are identified as PDSCH Occasion #1={TDRA #0, TDRA #1}, PDSCH Occasion #2={TDRA #2} and PDSCH Occasion #3={TDRA #3}.

Current proposals for a Type 1 (semi-static) HARQ codebook only allow a single HARQ feedback to be transmitted per PDSCH occasion. As a result and using the example above with reference toFIG.9, a Type 1 HARQ codebook can multiplex 3 PDSCH HARQ feedbacks, whereas there are in fact four PDSCH candidates.

Overlapping Intra-UE PDSCH

As will be appreciated from the above explanation, because more than one DCI may be transmitted to a UE, there is a possibility for intra-UE PDSCH transmissions in which two dynamically scheduled PDSCHs for a UE overlap in time. An example is shown inFIG.10. InFIG.10, a downlink grant of PDSCH resources580by a first DCI #1582transmitted in a first time slot302.1to a UE at time t0, schedules a transmission PDSCH #1 in slot n+2302.3(time t4to t7) as represented by an arrow583. At time t2, another DCI #2584is transmitted in a second time slot302.2to the same UE, which schedules a transmission PDSCH #2586in the slot n+2302.3at time t5to t6as represented by an arrow588. Here PDSCH #1580and PDSCH #2586overlap in time between t5to t6and also partially in frequency. Although in this example the two PDSCHs580,586also overlap in frequency, there can be two cases where:1. Two intra-UE PDSCH overlap in time but not in frequency2. Two intra-UE PDSCH overlap in time and frequency

A UE may not be capable of processing two PDSCH which overlap in time and in this case needs to drop one of them, for example by determining a relative priority between the PDSCHs and dropping the lower priority PDSCH. Although in this case, the gNB can be aware of which PDSCH the UE would drop, it desirable for the UE to provide HARQ feedback message to both PDSCHs (i.e. a NACK is sent for the dropped PDSCH) to that the wireless communications network is informed that the UE has not received a PDSCH transmission even if this is because the UE elected not to try to receive this transmission. That is to say that providing an obvious NACK for the dropped PDSCH to the gNB implicitly provides to the network an ACK for the PDCCH carrying the downlink grant for the dropped PDSCH in the DCI.

Currently proposed wireless communications systems do not expect that two PDSCHs will overlap in the same carrier or bandwidth part when scheduled by two independent downlink grants (DCI). As explained above, the HARQ codebooks of Type 1 and Type 2, but especially Type 1 have not been designed to provide for such HARQ feedback messages for overlapping PDSCHs because only a single HARQ feedback message is provided per PDSCH occasion. Hence, new methods are required to provide HARQ feedback messages for two overlapping PDSCH in the same UE.

Embodiments of the present technique can provide a communications device configured to transmit HARQ feedbacks to downlink data received from different downlink resources of a shared channel which overlap in time. The downlink data is communicated using an automatic repeat request technique such as a Hybrid ARQ technique. The communications device receives one or more downlink control messages indicating the different downlink communications resources for receiving the downlink data with an indication of resources of one or more uplink control channel for transmitting HARQ feedback messages indicating whether the downlink data was received (and decoded successfully) respectively from each granted resource of a downlink shared channel. The communications device detects that two of the downlink resources overlap in time, and applies one or more criteria or rules to determine whether the communications device can transmit HARQ feedbacks for the downlink data from the overlapping downlink communications resources. The one or more criteria (if not met) may determine that the communications device cannot transmit a HARQ feedback message for both of the two granted downlink communications resources which overlap, based for example on a location in time of the corresponding uplink resources for transmitting the respective HARQ feedback messages, a type of codebook used to form the HARQ feedback messages or whether the overlapping downlink resources are allocated to the same shared channel receiving occasion. Furthermore the communications device can in some examples provide a HARQ feedback message for the transport block transmitted on the downlink communications resources, even if the corresponding uplink control channels overlap in time, by adapting the HARQ feedback message which is transmitted. The wireless communications network can also determine that the communications device will transmit HARQ feedback for one of the selected transport blocks and take appropriate action including providing uplink resources for the HARQ feedback of the unacknowledged transport block in another uplink control channel occasion.

According to example embodiments a UE can be configured to apply criteria or restrictions to determine whether a HARQ feedback message can be provided for overlapping intra-UE PDSCHs. In some embodiments, if the criteria or restrictions are not met, the UE will only provide HARQ feedback message for a determined higher priority PDSCH and drop the feedback for a determined lower priority PDSCH.

In some example embodiments, if the criteria or restrictions are not met, the UE will provide a HARQ feedback message for the higher priority PDSCH using the PUCCH as indicated by the downlink grant indicated for example by following a K1indication in a PDSCH-to-HARQ_feedback field in the DCI. According to this example, the feedback for the lower priority PDSCH is delayed to a next PUCCH occasion.

Example Embodiment for Multiple PUCCHs Criteria

According to a first example embodiment, HARQ feedback messages are provided to both overlapping PDSCHs for the UE if each PDSCH is associated with a different HARQ codebook construction or associated with different PUCCH. This example embodiment is beneficial especially in Type 1 codebook where only a single HARQ feedback message is provided per PDSCH occasion and if the overlapping PDSCHs belong to different PUCCHs as indicated by different DCIs or the feedback is indicated according to a different HARQ codebook, then effectively these overlapping PDSCHs belong to different PDSCH occasions. That is, according to this example a rule is applied by the UE to determine that each of the PDSCH candidates directed by each DCI are determined to belong to different PDSCH occasions. As a result the UE can provide HARQ feedback messages for both overlapping PDSCHs but in different PUCCH transmissions.

As shown inFIG.11, as with the examples ofFIGS.6and8, the gNB transmits a first DCI #1620in the PDCCH of a first slot302.1, which indicates a location in the time and frequency resources of the PDSCH #1630where the gNB will transmit a transport block (PDSCH candidate) in a second slot n+2302.2as represented by an arrow640. A second DCI #2622is transmitted by the gNB in the PDCCH of the second slot n+2302.2, which indicates a location in the time and frequency resources of the PDSCH #2632where the gNB will transmit a transport block (PDSCH candidate) as represented by an arrow642in the second slot n+2302.2. Furthermore, each of the DCIs DCI #1620, DCI #2s622, also indicates communications resources in time and frequency of the uplink315where the UE270should transmit its HARQ feedback message in a PUCCH. As shown inFIG.11, the HARQ feedback message for PDSCH #1630is indicated to be in the PUCCH #1660of the fourth slot n+3312.4as represented by an arrow670and the HARQ feedback message for PDSCH #2632is indicated to be in the PUCCH #2662of the fifth slot n+3312.5as represented by an arrow672. As will be appreciated therefore, DCI #1620and DCI #2622schedules PDSCH #1630and PDSCH #2632respectively such that they overlap in time but not overlap in frequency. In this example embodiment, the UE performs a process to analyse whether it can provide a HARQ feedbacks for both overlapping PDSCHs. The UE determines whether it can provide HARQ feedbacks for both overlapping PDSCHs by determining whether the corresponding HARQ feedback message can be transmitted on a different PUCCH, e.g. PUCCH #1660and PUCCH #2662which inFIG.11are in different time slots n+3312.4and slot n+4312.5. Since different PUCCHs are used, the UE can therefore provide HARQ feedback message for these overlapping PDSCHs630,632. According to this example embodiments of the present technique can be configured to apply a restriction which determines whether the PUCCHs granted for HARQ feedbacks are the same and if the HARQ feedbacks share the same PUCCH, select a HARQ feedback corresponding to one or other of the PDSCHs to transmit.

According to the example embodiments, it does not matter whether the UE receives the downlink data from both of the PDSCH #1 and PDSCH #2 or only one of them. The predetermine criteria determine whether the UE can provide HARQ feedback for these overlapping PDSCHs that. If the UE cannot provide HARQ feedback for both PDSCH #1 and PDSCH #2 then it drop one of the HARQ feedback, but this may not be effected by whether or not it receives both of the PDSCH #1 and PDSCH #1 or not. This is because the UE may receive the downlink data from both PDSCH #1 and PDSCH #2 but still have to drop one of the HARQ feedbacks because the criteria such as the PUCCH resource/condition does not allow it to transmit both.

Example embodiments therefore include one or more predetermined criteria which can be used to apply a restriction on a minimum temporal proximity of the first uplink communications resource for transmitting the first HARQ feedback message with respect to the second uplink communications resource for transmitting the second HARQ feedback message. The applying the one or more predetermined criteria to determine that the UE can transmit HARQ feedbacks for both the first downlink data and the second downlink data includes determining that a temporal location of the first uplink communications resource and a temporal location of the second uplink communications resource are less than or equal the minimum temporal proximity restriction, and selecting to transmit HARQ feedback for one of the first downlink data or the second downlink data. The minimum temporal proximity restriction can be a slot or sub-slot. The restriction can be HARQ codebook type dependent (Type 1 or Type 2) and can include a restriction that the uplink resources granted for two HARQ feedback messages cannot be in the same slot, or cannot overlap in time as explained in the example below.

According to currently proposed wireless communications systems, there can only be one PUCCH carrying HARQ feedback message per slot312. However, it has been proposed to include more than one PUCCH carrying HARQ feedback messages per slot312to enable faster HARQ feedback message for URLLC transmissions. According to this proposal the K1granularity is in units of sub-slots rather than slots, which is less than a slot (e.g. 4 or 7 OFDM symbols). As explained above, K1is a number of slots after the PDSCH transmission where the uplink resources of the PUCCH are provided for transmitting the ACK/NACK. By arranging for the K1value to be in units of sub-slots rather than slots, the HARQ feedback for an eMBB PDSCH can be arranged to use a first HARQ codebook such as a legacy codebook where K1is in units of slots and the HARQ feedback for a URLLC PDSCH can be arranged to use a second HARQ codebook where K1is in units of sub-slots. As such, and according to the example ofFIG.11a UE can be configured according to this example where a PUCCH transmission occurs in the same slot, i.e. the said minimum temporal proximity restriction is a slot. An example is shown inFIG.12, which is an example based onFIG.11and so only the differences will be described.

As shown inFIG.12the gNB transmits a first DCI #1720in the PDCCH of a first slot302.1, which indicates a location in the time and frequency resources of the PDSCH #1730of a PDSCH candidate in a third slot n+2302.3as represented by an arrow740. A second DCI #2722is transmitted by the gNB in the PDCCH of the second slot n+2302.2, which indicates a location in the time and frequency resources of the PDSCH #2732of a PDSCH candidate as represented by an arrow742in the third slot n+2302.3. As for the example ofFIG.11, each of the DCIs DCI #1720, DCI #2s722, also indicates communications resources in time and frequency of the PUCCH of the uplink315where the UE270should transmit its HARQ feedback message. For the example embodiment ofFIG.12, the HARQ feedback message for PDSCH #1730is indicated to be in the PUCCH #1760of the fourth slot n+3312.4as represented by an arrow770and the HARQ feedback message for PDSCH #2732is indicated to be in the PUCCH #2762as represented by an arrow772, which is in the same slot n+3312.4as the PUCCH #1760.

For the example ofFIG.12, overlapping PDSCHs PDSCH #1730, PDSCH #2732are associated with HARQ feedback message messages transmitted in the PUCCH of slot n+3312.4PUCCH #1760, PUCCH #2762respectively. However in contrast to the example shown inFIG.11, the PUCCH #1760and PUCCH #2762are in the same slot n+3312.4but in different sub-slots780,782. According to this example, the PDSCH transmissions may be carrying downlink data for different services and therefore have a differently configured HARQ feedback message. For example, PDSCH #1 can be an eMBB transmission using a legacy HARQ codebook whilst PDSCH #2 can be a URLLC transmission using the sub-slot based HARQ codebook. According to this example therefore the UE is configured to determine whether to transmit HARQ feedbacks for the downlink data transmitted via the respective PDSCH transmissions PDSCH #1, PDSCH #2 by identifying that it can transmit the HARQ feedback (ACK/NACK) in separate PUCCHs, even though they are allocated to the same slot because the HARQ codebook for one of those PUCCH transmissions is for a service which allows transmission on a sub-slot basis which does not overlap in time. That is to say the said minimum temporal proximity restriction is a sub-slot According to this example embodiment therefore the UE is configured to detect whether the HARQ feedback messages are to be transmitted in different sub-slots and different codebooks and if not, select a HARQ feedback for one of the PDSCHs to transmit.

In another example in which multiple PUCCHs carrying HARQ feedback messages are allocated for the same slot (or sub-slot), the criteria/requirement for the UE to transmit HARQ feedback for the downlink data from the corresponding PDSCH requires that the PUCCHs associated with the overlapping PDSCHs, do not overlap in time. An example is shown inFIG.13, which corresponds to the same example ofFIG.12except that the first DCI DCI #1720indicates with an arrow774a first PUCCH #1790in the first sub-slot780, which overlap in time with resources for the UE to transmit a second HARQ feedback message between the first and the second sub-slots780,782of a second PUCCH #2792as represented by an arrow776. According to this example embodiment, the UE determines that it cannot transmit the HARQ feedback message (ACK/NACK) for both the overlapping PDSCHs PDSCH #1, PDSCH #2 because an associated PUCCH transmission indicated by the DCIs overlap in time. Therefore an example condition which triggers a procedure to select a HARQ feedback for one of the PDSCH candidates to transmit is if the associated PUCCH transmission for the HARQ feedback message overlaps in time.

According to this example, for a plurality of PUCCHs carrying HARQ feedback messages in the same slot or sub-slot, the UE determines whether the PUCCHs are associated with the overlapping PDSCHs overlap in time. As illustrated by the example ofFIG.13, the PUCCHs PUCCH #1790, PUCCH #2792overlap in time. For this example, the UE determines a relative priority between receiving the downlink data from the respective PDSCHs and will either drop a lower priority PUCCH or multiplex the HARQ feedbacks from PUCCH #1 and PUCCH #2 into a single PUCCH using multiplexing rules for example those defined in our co-pending European patent application 19166662.7 [9], the content of which are incorporated herein by reference.

According to another example embodiment, a UE may detect that resources of a PUCCH have been allocated for transmitting a HARQ feedback message for two different PDSCHs which overlap in time and therefore collide. The UE then determines that it can transmit the HARQ feedback message for the different PDSCHs even though the corresponding PUCCH overlap in time by multiplexing the HARQ feedback messages into the same PUCCH. The HARQ feedback messages are therefore multiplexed into one of the PUCCH resources.

For an example in which the UE determines that it must compromise on the number of HARQ feedbacks which it transmit, the UE identifies a relative priority between receiving the downlink data from different PDSCHs. The UE then drops transmission of a PUCCH associated with a lower priority PDSCH and allocates any capacity of the remaining PUCCH after this capacity has been allocated to transmit the HARQ feedback messages for the higher priority PDSCH to the lower priority PDSCH. That is to say that a capacity available in the PUCCH is firstly given to the HARQ feedbacks corresponding to the higher priority downlink data and the HARQ feedbacks corresponding to the lower priority PDSCH is then multiplexed to the PUCCH. For example, if PUCCH #1 contains HARQ feedback messages for four eMBB PDSCHs and PUCCH #2 contains HARQ feedback messages for three URLLC PDSCHs, as provided in our co-pending European patent application 19166662.7 [9], some of the bits in PUCCH #1 are multiplexed into the PUCCH #2 and the PUCCH #1 transmission is dropped, assuming that the PUCCH associated with the eMBB PDSCHs has a lower priority. If there is insufficient capacity in the PUCCH #2 to carry all the HARQ feedback messages (seven HARQ feedback messages in total for all of the eMBB PDSCHs and URLLC PDSCHs), then some of the HARQ feedback messages belonging to PUCCH #1 are dropped. According to this embodiment the gNB will know that a HARQ feedback message corresponding to a lower priority eMBB PDSCH that overlaps a URLLC PDSCH will be dropped. Since the gNB knew the UE would drop the lower priority overlapping PDSCH, it is beneficial to transmit the HARQ feedbacks for the other PDSCHs where the gNB does not know the decoding outcome. This example corresponds to a case where the lower priority overlapping PDSCH is always dropped. However, this may not always be the case since there are some scenarios where the UE can process both overlapping PDSCHs especially when they do not overlap in frequency.

According to another example embodiment, the UE is configured to detect that the it will drop one of the PDSCHs according to the predetermined criteria and to signal implicitly to the gNB that it has dropped this PDSCH using the HARQ feedback message transmitted in the PUCCH for the PDSCH which it has selected to be received. Thus where the PUCCHs associated with the overlapping PDSCHs, also overlap in time, the UE can be configured to transmit the PUCCH associated with the higher priority PDSCH and use a different scrambling on that PUCCH to that which is expected by the gNB. The reason for signaling to the gNB that the UE has dropped the PDSCH is to provide the gNB with an indication that it has received the downlink grant for the associated PDSCH (DCI). For the case where the lower priority PDSCH is always dropped the rationale for transmitting a HARQ feedback message for a dropped PDSCH is to acknowledge implicitly the reception of the downlink grant associated with the dropped PDSCH. Hence, the use of a different scrambling code used on transmitting the HARQ feedback message via the PUCCH provides this implicit acknowledgement. Referring to the example inFIG.13, the PDSCH #1 is determined to have a lower priority PDSCH (e.g. eMBB) than PDSCH #2 which has a higher priority PDSCH (e.g. URLLC). Here the associated PUCCHs overlap in time and in this embodiment, the UE drops PUCCH #1 but uses a different scrambling on PUCCH #2 to indicate a successful reception of DCI #1.

In another embodiment where the PUCCHs associated with the overlapping PDSCHs, also overlap in time, the UE transmits the PUCCH associated with the higher priority PDSCH. The PUCCH associated with the lower priority PDSCH can be delayed to another PUCCH occasion. A delay procedure according to one of the examples disclosed in our co-pending European patent application 19166662.7 [9] can be used.

Example Embodiment for Single PUCCH Criteria

Example embodiments described above provide an arrangement in which a UE is configured to manage transmission of HARQ feedbacks for downlink data in which HARQ feedback messages are required to be transmitted for overlapping PDSCHs, which the UE determines it can do if the HARQ feedback messages for these PDSCHs can be transmitted in different PUCCHs associated with the PDSCHs. The following embodiments consider example criteria/requirements for scenarios in which the overlapping PDSCHs share the same PUCCH or HARQ feedback message according to the same codebook.

According to an example embodiment, HARQ feedback messages are provided for overlapping PDSCHs if these messages can be transmitted using Type 2 (dynamic) HARQ codebook. As explained above, the Type 2 HARQ codebook makes use of the DAI field to ensure that the correct number of HARQ feedback bits are transmitted in the associated PUCCH. Hence, the DAI counter can take account of any PDSCHs, which the UE may selects to drop (not receive the downlink data from the PDSCH) in the overlapping PDSCHs. An example embodiment is shown inFIG.14, which again corresponds to the examples presented above. As shown inFIG.14, in the PDCCH of slots n, n+1, n+2,302.1,302.2,302.3the UE receives from the gNB DCI #1820, DCI #2822and DCI #3824respectively. These DCIs respectively schedule PDSCH #1830, PDSCH #2832and PDSCH #3830as represented by arrows840,842,844and a PUCCH860for the UE to transmit a HARQ feedback message for these PDSCHs as represented by arrows870,872,874. However the PDSCH #2832and the PDSCH #3834overlap in time. For this example, the data carried by PDSCH #2832is determined by the UE to have a lower relative priority and because the PDSCH #2 and PDSCH #3 overlap in time, the UE determines e.g. according to the UE's capability that it should drop PDSCH #2 in the sense that it does not receive downlink data transmitted in PDSCH #2832as represented by a X879. Since a Type 2 codebook is used, the DAI counter is incremented for each of the PDSCHs830,832,834and hence the UE can provide a HARQ feedback message for both the PDSCH #2832and PDSCH #3834which overlap in time, even though it did not receive the downlink data from the PDSCH #2832. Assuming that the UE successfully decodes PDSCH #1830and PDSCH #3834, the UE transmits a combined HARQ feedback message in the allocated PUCCH resources860with a HARQ feedback message={101} for {PDSCH #1, PDSCH #2, PDSCH #3}.

According to another example embodiment, HARQ feedback messages for the overlapping PDSCHs can be provided using a Type 1 codebook if the overlapping PDSCHs belong to different PDSCH occasions. Otherwise the conditions or criteria/requirement which allow the UE to transmit HARQ feedback for downlink data from PDSCHs which overlap in time are considered not to have been met. Using the TDRA table example inFIG.8above, HARQ feedback messages are provided for two PDSCHs that overlap if these PDSCHs correspond to TDRA #0 and TDRA #2. However, if TDRA #0 and TDRA #1 are scheduled by different downlink grant indications (DCI), then the UE can provide only a HARQ feedback message for a determined relatively higher priority PDSCH and so must select a HARQ feedback for one of these PDSCHs.

In another example embodiment, for the case where the overlapping PDSCHs belong to the same PDSCH occasion of a Type 1 codebook, the UE can provide the HARQ feedback for a higher priority PDSCH and use a different scrambling for an associated PUCCH. An example is shown inFIG.14, which uses the same TDRA table in Table 1 and corresponds to the example embodiment inFIG.9and so only the differences with respect toFIG.9will be described. As shown inFIG.14, two DCIs DCI #1920, DCI #2922are received in a first time slot n302.1. These DCIs DCI #1920, DCI #2922schedule an allocation of downlink resources on PDSCHs520,522as represented by arrows940,942that correspond to TDRA #0 and TDRA #1, causing these scheduled PDSCHs520,522to overlap in time. For this example, it is assumed that the PDSCH scheduled by the later grant DCI #2922has higher priority. The UE therefore determines that it should drop the PDSCH #1520corresponding to TDRA #0, in that it should not attempt to receive the downlink data transmitted in the PDSCH #1520. According to this example, the UE can provide a HARQ feedback message for TDRA #1 for the PDSCH occasion but the UE uses a different scrambling code for transmitting the HARQ feedback message to indicate that the downlink data transmitted PDSCH #1, was not received (NACK). The UE therefore does not select which PDSCH to drop, but determines which of the HARQ feedbacks it can transmit. According to this example the UE can drop a PDSCH but still transmit an indication of the HARQ feedback, because the restriction is one transmitting conflicting HARQ feedbacks, which may require either one of the HARQ feedbacks to drop or an adaptation of another transmission such as the HARQ feedback which can be transmitted to convey an indication of the HARQ feedback for a PDSCH whish is dropped.

As will be appreciated from the example embodiment described above with reference toFIG.14, in other examples more than one PDSCH occasion can contain overlapping PDSCHs. For this example, a different PUCCH scrambling code can be used for each different number of PDSCH occasion with overlapping PDSCHs. For example if there are three PDSCH occasions in a Type 1 codebook there can be:Eight different scrambling codes for the PUCCH to indicate which PDSCH occasion has overlapping PDSCHThree different scrambling codes can be used to indicate the number of PDSCH occasions with overlapping PDSCH

In another embodiment, if the overlapping PDSCHs belong to the same PDSCH occasion (of Type 1 HARQ feedback codebook), the UE can provide a HARQ feedback message for the higher priority PDSCH and delay the HARQ feedback for the lower priority PDSCH, for example to another PUCCH occasion or in the next sub-slot or slot.

Other Example Embodiments

In another embodiment HARQ feedback messages for overlapping PDSCHs can be activated by RRC signaling, otherwise the UE can provide a HARQ feedback message only for the higher priority PDSCH. In another embodiment HARQ feedback messages for the overlapping PDSCHs can be activated by MAC signaling. Otherwise the UE can provide a HARQ feedback message only for the higher priority PDSCH. In another embodiment HARQ feedback messages for the overlapping PDSCHs can be activated by a Group Common DCI. Otherwise the UE can provide HARQ feedback only for the higher priority PDSCH. In another example embodiment HARQ feedback messages for the overlapping PDSCHs can be indicated in a DCI providing the downlink grant. Otherwise the UE can provide HARQ feedback only for a higher priority PDSCH. In another embodiment a higher priority PDSCH can be the PDSCH scheduled by the later grant. For example inFIG.10, the PDSCH #2 is considered to have a higher priority than PDSCH #1 because PDSCH #2 is scheduled by DCI #2 which is transmitted after DCI #1 (which schedules PDSCH #1).

In another embodiment, whether a lower priority PDSCH is dropped or not can depend on a UE's capability to receive and to decode overlapping PDSCHs. If a UE can support this capability, the UE decodes both PDSCHs otherwise the UE will always drop a lower priority PDSCH.

In another embodiment example, whether a lower priority PDSCH is dropped or not depends on a UE's capability regarding a PDSCH processing time. According to currently proposed systems, the PDSCH processing time N1, has been specified depending on PDSCH processing capability. For example, in the case of 15 kHz subcarrier spacing, a processing time for one PDSCH is three OFDM symbols for PDSCH processing capability two (suitable for URLLC). In this example embodiment, when a time gap TPDSCH, between the overlapped PDSCH and PUCCH is over a specific length (e.g. 6 or more OFDM symbols), the lower priority PDSCH is not dropped, otherwise it is dropped. For example referring toFIG.14, this time gap TPDSCHis between time t7and t8where the overlapping PDSCHs are PDSCH #2 and PDSCH #3. Assuming the PDSCH processing time is N1=3 symbols then the UE can only process both PDSCHs if TPDSCH≥M×N1. Here M can be equal to the number of overlapped PDSCHs, e.g. in this example M=2. Alternatively, M can be a UE capability, which is pre-specified and known deterministically so that the PDSCH processing time for the overlapped PDSCH can be newly specified.

It should be appreciated that the predetermined criteria described in above example embodiments are applicable whether the overlapping PDSCHs are both decoded or one of the PDSCHs is dropped. That is, if the predetermined criteria is met, the UE can provide feedbacks for BOTH overlapping PDSCHs even if the UE dropped the lower priority PDSCH (a NACK is sent for the dropped PDSCH). On the other hand, if the predetermined criteria is NOT met, the UE will provide HARQ feedback for ONE of the overlapping PDSCHs even though the UE can decode BOTH PDSCHs. The latter case may be cause by poor scheduling implementation and here the UE can decide not to decode both PDSCH.

Summary of Operation

FIG.16provides an example operation of a communications device (UE) which summarises the example embodiments explained above. According to this example, the UE operates as shown inFIG.16, which is summarised as follows:

In a first step S14, the UE receives DCI #1 and DCI #2 and from the DCI #1 and DCI #2 identifies respectively a location of the PDSCH #1 in which the first downlink data is to be transmitted and a location of the PDSCH #2 in which the second downlink data is to be transmitted by the gNB. The UE also identifies in this step S14the uplink communications resources of the corresponding PUCCH #1 and PUCCH #2 where the UE should transmit its HARQ feedback message (ACK/NACK) in response to the first and second downlink data. However in step S15, the UE identifies whether the communications resources of the PDSCH #1 and PDSCH #2 overlap in time. If the PDSCH #1 and PDSCH #2 overlap in time then in step S16the UE applies one or more pre-configured or predetermined criteria to determine whether or not it can transmit HARQ feedback for both of the first and second downlink data transmitted in the PDSCH #1 and PDSCH #2. At decision point S17, the UE decides according to the analysis of the pre-configured criteria in step S16whether it can transmit HARQ feedback for both the PDSCH #1 and PDSCH #2. If it can then processing proceeds to step S19. If the UE cannot transmit HARQ feedback for both of PDSCH #1 and PDSCH #2 then in process step S18, the UE determines whether to transmit a HARQ feedback for the first downlink data received in the PDSCH #1 or the second downlink data in the PDSCH #2.

A further more detailed example is provided by the flow diagram ofFIG.17.FIG.17is summarised as follows:

As explained above with reference toFIG.5, and as with step S14ofFIG.16as a first step the UE receives DCI #1 and DCI #2. The UE then identifies (S22) from the DCI #1 a location of the PDSCH #1 in which the first downlink data is to be transmitted by the gNB and a location of the PDSCH #2 in which the second downlink data is to be transmitted by the gNB. The UE also identifies in this step S22a location of the uplink resources of the corresponding PUCCH #1 and PUCCH #2 where the UE should transmit its HARQ feedback message (ACK/NACK) in response to the first and second downlink data. At decision point S24the UE determines whether the resources of the granted PDSCH #1 and PDSCH #2 overlap in time. If they do then processing proceeds to step S26in which the UE applies predetermined criteria or conditions for determining whether it can transmit one or both of the HARQ feedbacks on the respective PUCCH #1 and PUCCH #2 and if not, according to these criteria selects one of the PUCCH #1 or PUCCH #2. Step S26includes the operations of steps S16, S17and S18ofFIG.16At decision point S28, the UE determines whether the first PUCCH #1 or the second PUCCH #2 was selected in step S26and correspondingly therefore whether a HARQ feedback message for first downlink data transmitted in the PDSCH #1 or the second downlink data transmitted on the PDSCH #2 can be transmitted. For example, if the UE determine in strep S26that it can transmit only one of the HARQ feedbacks, then the UE may identify which of the PDSCH #1 or PDSCH #2 will carry the higher priority data and select to transmit the HARQ feedback on the PUCCH with the higher relative priority. If the first uplink resource for the PUCCH #1 for the HARQ feedback in response to the first downlink data was selected then processing proceeds from the decision point S28to step S30in which the UE receives the first downlink data on the PDSCH #1 and in step S32generates a HARQ feedback message for transmission on the PUCCH #1. At step S34the UE adapts the transmission of the HARQ feedback message on the PUCCH #1 to provide feedback for PDSCH #2 for example by using a different scrambling code which is known to the gNB. The process then ends at step S48.

From decision point S28, if the PUCCH #1 was not selected then processing proceeds to step S36, S38and S40, which correspond to steps S30to S34described above except for the second downlink data instead of the first downlink data and generates a HARQ feedback message for transmission in the PUCCH #2 and adapts the transmission of the HARQ feedback on PUCCH #2 to provide a HARQ feedback NACK to indicated that the first downlink data transmitted on the PDSCH #1 was not received. Processing then ends at step S48.

If the PDSCH #1 and PDSCH #2 do not overlap then the UE performs steps S42to S46in accordance with the operations ofFIG.5to receive the first and the second downlink data and to transmit HARQ feedback messages on the PUCCH #1 and PUCCH #2. Steps S42to S46also represent operations performed for step S19inFIG.16. The process ends at step S48. Similarly, although steps S30and S38indicate that the downlink data is received from the PDSCH #1 and PDSCH #2, it will be appreciated from the above explanation and the example shown inFIG.16that the downlink data can be received from both the PDSCH #1 and the PDSCH #2 with only one of the HARQ feedbacks transmitted in the selected PUCCH #1 or PUCCH #2.

It will be appreciated that while the present disclosure has in some respects focused on implementations in an LTE-based and/or 5G network for the sake of providing specific examples, the same principles can be applied to other wireless telecommunications systems. Thus, even though the terminology used herein is generally the same or similar to that of the LTE and 5G standards, the teachings are not limited to the present versions of LTE and 5G and could apply equally to any appropriate arrangement not based on LTE or 5G and/or compliant with any other future version of an LTE, 5G or other standard.

It may be noted various example approaches discussed herein may rely on information which is predetermined/predefined in the sense of being known by both the base station and the communications device. It will be appreciated such predetermined/predefined information may in general be established, for example, by definition in an operating standard for the wireless telecommunication system, or in previously exchanged signalling between the base station and communications devices, for example in system information signalling, or in association with radio resource control setup signalling, or in information stored in a SIM application. That is to say, the specific manner in which the relevant predefined information is established and shared between the various elements of the wireless telecommunications system is not of primary significance to the principles of operation described herein. It may further be noted various example approaches discussed herein rely on information which is exchanged/communicated between various elements of the wireless telecommunications system and it will be appreciated such communications may in general be made in accordance with conventional techniques, for example in terms of specific signalling protocols and the type of communication channel used, unless the context demands otherwise. That is to say, the specific manner in which the relevant information is exchanged between the various elements of the wireless telecommunications system is not of primary significance to the principles of operation described herein.

It will be appreciated that the principles described herein are not applicable only to certain types of communications device, but can be applied more generally in respect of any types of communications device, for example the approaches are not limited to machine type communication devices/IoT devices or other narrowband communications devices, but can be applied more generally, for example in respect of any type communications device operating with a wireless link to the communication network.

It will further be appreciated that the principles described herein are not applicable only to LTE-based wireless telecommunications systems, but are applicable for any type of wireless telecommunications system that supports a random access procedure comprising an exchange of random access procedure messages between a communications device and a base station.

Further particular and preferred aspects of the present invention are set out in the accompanying independent and dependent claims. It will be appreciated that features of the dependent claims may be combined with features of the independent claims in combinations other than those explicitly set out in the claims.

Thus, the foregoing discussion discloses and describes merely exemplary embodiments of the present invention. As will be understood by those skilled in the art, the present invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. Accordingly, the disclosure of the present invention is intended to be illustrative, but not limiting of the scope of the invention, as well as other claims. The disclosure, including any readily discernible variants of the teachings herein, define, in part, the scope of the foregoing claim terminology such that no inventive subject matter is dedicated to the public.

Respective features of the present disclosure are defined by the following numbered paragraphs:

Paragraph 1. A method of receiving data by a communications device in a wireless communications network, the method comprisingreceiving one or more downlink control messages providing a grant of a first downlink communications resource of a wireless access interface from which the communications device can receive first downlink data, a grant of a second downlink communications resource of the wireless access interface from which the communications device can receive second downlink data, and information of a one or more allocations of an uplink communications resource of the wireless access interface for the communications device to transmit a first hybrid automatic repeat request-type, HARQ, feedback message for indicating whether or not the first downlink data is correctly received, and information of a one or more allocations of an uplink communications resource of the wireless access interface for the communications device to transmit a second hybrid automatic repeat request-type, HARQ, feedback message for indicating whether or not the second downlink data is correctly received,detecting that the first downlink communications resource and the second downlink communications resource of the wireless access interface overlap in time, andapplying one or more predetermined criteria to determine whether the communications device can transmit one or both of the first HARQ feedback message on the allocated uplink communications resource and the second HARQ feedback message on the allocated uplink communications resource, andin response to receiving one or both of the first downlink data from the first downlink communications resources and the second downlink data from the second downlink communications resources, transmitting the determined HARQ feedback message for one or both of the received first and second downlink data.

Paragraph 2. The method of paragraph 1, wherein the allocated uplink communications resource comprises a first uplink communications resource for transmitting the first HARQ message and a second uplink communications resource for transmitting the second HARQ message, and the one or more predetermined criteria include a requirement that the first uplink communications resource is different from the second uplink communications resource for the communications device to transmit both of the first HARQ feedback message and the second HARQ feedback message and the applying the one or more predetermined criteria comprises selecting of the first and the second HARQ feedback message to transmit if the first and the second uplink communications resources are not different.

Paragraph 3. The method of paragraph 2, wherein the one or more predetermined criteria include a restriction on a minimum temporal proximity of the first uplink communications resource for transmitting the first HARQ feedback message with respect to the second uplink communications resource for transmitting the second HARQ feedback message, and the applying the one or more predetermined criteria to determine that the communications device can transmit the first HARQ feedback or the second HARQ feedback includes determining that a temporal location of the first uplink communications resource and a temporal location of the second uplink communications resource are less than or equal the minimum temporal proximity restriction, and selecting to transmit one of the first HARQ feedback or the second HARQ feedback.

Paragraph 4. The method of paragraph 2 or 3, wherein the wireless access interface comprises a time divided structure providing communications resources in time divided units and in frequency for the uplink and the downlink, and the restriction on the minimum temporal proximity of the first uplink communications resource for transmitting the first HARQ feedback message with respect to the second uplink communications resource for transmitting the second HARQ feedback message comprises whether the first uplink resources are in the same time divided unit of the uplink wireless access interface.

Paragraph 5. The method of paragraph 2 or 3, wherein the wireless access interface comprises a time divided structure providing communications resources in time divided units and in frequency for the uplink and the downlink, and first HARQ feedback message and the second HARQ feedback message are generated by the communications device according to a first codebook or a second codebook, and the one or more predetermined criteria include a restriction on the first uplink resources being in the same time divided unit of the uplink wireless access interface and being generated by the same codebook, and the applying the one or more predetermined criteria to determine that the communications device can transmit the first HARQ feedback or the second HARQ feedback includes determining that the first uplink communications resource and the second uplink communications resource are generated using the same codebook, and selecting to transmit one of the first HARQ feedback or the second HARQ feedback.

Paragraph 6. The method of paragraph 5, wherein the time divided structure of the wireless access interface includes sub-units, and the one or more predetermined criteria include a restriction on the first uplink resources not being in the same sub-unit of the same time divided unit, the applying the one or more predetermined criteria to determine that the communications device can transmit the first HARQ feedback or the HARQ feedback includes detecting that the first uplink resources are in the same sub-unit as the second uplink resources.

Paragraph 7. The method of paragraph 5 or 6, wherein the one or more predetermined criteria include the first uplink communications resource for transmitting the first HARQ feedback message not overlapping in time with the second uplink communications resource for transmitting the second HARQ feedback message.

Paragraph 8. The method of paragraphs 1 to 7, wherein the determining whether the communications device can transmit a HARQ feedback message for one or both of the first downlink data from the first communications resource and the second downlink data from the second communications resource comprisesdetermining in accordance with the predetermined criteria that a HARQ feedback message can be transmitted on either of the first downlink data from the first communications resource or the second downlink data from the second communications resource, anddetermining a relative priority of the first downlink data and the second downlink data, andselecting to transmit HARQ feedback on the first uplink communications resources or the second uplink communications resources in accordance with which of the first downlink data and the second downlink data has the higher priority.

Paragraph 9. The method of any of paragraphs 1 to 8, wherein if the first HARQ feedback message is transmitted, the transmitting the first HARQ feedback message includes adapting the first HARQ feedback message to indicate that the second downlink data was not received, and if the second HARQ feedback message is transmitted, the transmitting the second HARQ feedback message includes adapting the second HARQ feedback message to indicate that the first downlink data was not received.

Paragraph 10. The method of paragraph 9, wherein the adapting the first HARQ feedback message or the second HARQ feedback message comprises using a different scrambling code when transmitting the HARQ feedback message to that expected by the wireless communications network.

Paragraph 11. The method of any of paragraphs 1 to 10, comprising receiving the first downlink data from the first downlink communications resources, receiving the second downlink data from the second downlink communications resources and not transmitting the first HARQ feedback message in the granted uplink resources if according to the predetermined criteria the first HARQ feedback message is not selected or not transmitting the second HARQ feedback message in the granted uplink resources if according to the predetermined criteria the second HARQ feedback message is not selected.

Paragraph 12. The method of any of paragraphs 1 to 11, comprising delaying transmitting the first HARQ feedback message in the uplink resources if according to the predetermined criteria the first HARQ feedback message is not selected to be transmitted or not transmitting the second HARQ feedback message in the granted uplink resources if according to the predetermined criteria the second HARQ feedback message is not selected to be transmitted.

Paragraph 13. The method of any of paragraphs 2 to 12, comprising multiplexing the first and second HARQ feedback message and transmitting both of the first and the second HARQ feedback messages using the first uplink communications resources or the second uplink communications resources.

Paragraph 14. A method of paragraph 1, wherein the one or more allocations of an uplink communications resource comprises the same uplink communications resource.

Paragraph 15. The method of paragraph 14, wherein the first and second downlink control messages are part of a plurality of downlink control messages which grant a plurality of downlink communications resources of a shared channel of the wireless access interface for the communications device to receive a corresponding plurality of the downlink data including the first and the second downlink data, the method comprisingusing predetermined rules to divide the plurality of downlink communications resources into a plurality of downlink shared channel occasions, the first downlink communications resources for receiving the first downlink data being in the same downlink shared channel occasion as the second downlink communications resource for receiving the second downlink data, and the applying one or more predetermined criteria to select whether to transmit the first HARQ feedback or the second HARQ feedback comprisesdetermining a relative priority between the first downlink data and the second downlink data, andselecting to transmit the first or the second HARQ feedback corresponding to the downlink data with the higher priority.

Paragraph 16. The method of paragraphs 14 or 15, comprising multiplexing the first and second HARQ feedback messages and transmitting both of the first and the second HARQ feedback messages in the uplink communications resource.

Paragraph 17. The method of any of paragraphs 14, 15 or 16, wherein if the first downlink data is received, the transmitting the first HARQ feedback message includes adapting the first HARQ feedback message to indicate that the second downlink data was not received, and if the second downlink data is received, the transmitting the second HARQ feedback message includes adapting the second HARQ feedback message to indicate that the first downlink data was not received.

Paragraph 18. The method of paragraph 16, wherein the adapting the first HARQ feedback message or the second HARQ feedback message comprises using a different scrambling code when transmitting the HARQ feedback message to that expected by the wireless communications network.

Paragraph 19. A method of receiving data by a communications device in a wireless communications network, the method comprisingreceiving one or more downlink control messages providing a grant of a first downlink communications resource of a wireless access interface from which the communications device can receive first downlink data, a grant of a second downlink communications resource of the wireless access interface from which the communications device can receive second downlink data, and information of a one or more allocations of an uplink communications resource of the wireless access interface for the communications device to transmit a first hybrid automatic repeat request-type, HARQ, feedback message for indicating whether or not the first downlink data is correctly received, and information of a one or more allocations of an uplink communications resource of the wireless access interface for the communications device to transmit a second HARQ feedback message for indicating whether or not the second downlink data is correctly received,detecting that the first downlink communications resource and the second downlink communications resource of the wireless access interface overlap in time, andapplying one or more predetermined criteria to determine whether the communications device can transmit HARQ feedback message for one or both of the first HARQ feedback message for transmission on the first uplink communications resources or the second HARQ feedback message for transmission on the second uplink communications resources,receiving one or both of the first downlink data from the first downlink communications resources and the second downlink data from the second downlink communications resources, andin accordance with the determined conditions if it has been determined to transmit the first HARQ feedback message via the first uplink communications resources, adapting the first HARQ feedback message transmitted on the first uplink communications resources to provide an indication of the second HARQ feedback for the second downlink data, or if it has been determined to transmit the second HARQ feedback message via the second uplink communications resources, adapting the second HARQ feedback message transmitted on the second uplink communications resources to provide an indication of the first HARQ feedback for the first downlink data.

Paragraph 20. A communications device for receiving data from a wireless communications network, the communications device comprisingreceiver circuitry configured to receive signals transmitted via a wireless access interface provided by the wireless communications network,transmitter circuitry configured to transmit signals via the wireless access interface, andcontroller circuitry configured to control the receiver circuitryto receive one or more downlink control messages providing a grant of a first downlink communications resource of the wireless access interface from which the communications device can receive first downlink data, a grant of a second downlink communications resource of the wireless access interface from which the communications device can receive second downlink data, and a grant of a one or more allocations of an uplink communications resource of the wireless access interface for the communications device to transmit a first automatic repeat request-type, HARQ, feedback message for indicating whether or not the first downlink data is received and to transmit a second automatic repeat request-type feedback message for indicating whether or not the second downlink data is received, the controller circuitry being configuredto detect that the first downlink communications resource and the second downlink communications resource of the wireless access interface overlap in time,to apply one or more predetermined criteria to determine whether the communications device can transmit one or both of the first HARQ feedback message on the allocated uplink communications resource and the second HARQ feedback message on the allocated uplink communications resource, andto control the receiver circuitry in accordance with the applied predetermined criteria to receive one or both of the first downlink data and the second downlink data, and to control the transmitter circuitryto transmit the determined HARQ feedback message for one or both of the received first and second downlink data.

Paragraph 21. A communications device for receiving data from a wireless communications network, the communications device comprisingreceiver circuitry configured to receive signals transmitted via a wireless access interface provided by the wireless communications network,transmitter circuitry configured to transmit signals via the wireless access interface, andcontroller circuitry configured to control the receiver circuitryto receive one or more downlink control messages providing a grant of a first downlink communications resource of a wireless access interface from which the communications device can receive first downlink data, a grant of a second downlink communications resource of the wireless access interface from which the communications device can receive second downlink data, and information of a one or more allocations of an uplink communications resource of the wireless access interface for the communications device to transmit a first hybrid automatic repeat request-type, HARQ, feedback message for indicating whether or not the first downlink data is correctly received, and information of a one or more allocations of an uplink communications resource of the wireless access interface for the communications device to transmit a second HARQ feedback message for indicating whether or not the second downlink data is correctly received, the controller circuitry being configuredto detect that the first downlink communications resource and the second downlink communications resource of the wireless access interface overlap in time, andto apply one or more predetermined criteria to determine whether the communications device can transmit HARQ feedback message for one or both of the first HARQ feedback message for transmission on the first uplink communications resources or the second HARQ feedback message for transmission on the second uplink communications resources, and to control the receiver circuitryto receive one or both of the first downlink data from the first downlink communications resources and the second downlink data from the second downlink communications resources, andin accordance with the determined conditions if it has been determined to transmit the first HARQ feedback message via the first uplink communications resources, to adapt the first HARQ feedback message transmitted on the first uplink communications resources to provide an indication of the second HARQ feedback for the second downlink data, or if it has been determined to transmit the second HARQ feedback message via the second uplink communications resources, to adapt the second HARQ feedback message transmitted on the second uplink communications resources to provide an indication of the first HARQ feedback for the first downlink data.

Paragraph 22. A method of operating an infrastructure equipment of a wireless communications network to transmit data to a communications device, the method comprisingtransmitting one or more downlink control messages to the communications device providing an indication of a first downlink communications resource of a wireless access interface from which the communications device can receive first downlink data, an indication of a second downlink communications resource of the wireless access interface from which the communications device can receive second downlink data, and an indication of one or more allocations of an uplink communications resource of the wireless access interface for the communications device to transmit a first automatic repeat request-type, HARQ, feedback message for indicating whether or not the first downlink data is received and to transmit a second HARQ feedback message for indicating whether or not the second downlink data is received,identifying that the first downlink communications resource and the second downlink communications resource of the wireless access interface overlap in time, andreceiving either the first HARQ feedback message in the granted uplink communications resource indicating whether or not the first downlink data was received, orreceiving the second HARQ feedback message in the granted uplink communications resource to indicate whether or not the second downlink data was received, andidentifying from either the received first HARQ feedback message that the second downlink data was not received or from the received second HARQ feedback message that the first downlink data was not received.

Paragraph 23. An infrastructure equipment forming part of a wireless communications network, the infrastructure equipment comprisingreceiver circuitry configured to receive signals transmitted from one or more communications devices via a wireless access interface provided by the wireless communications network,transmitter circuitry configured to transmit signals to the one or more communications devices via the wireless access interface, andcontroller circuitry configured to control the transmitter circuitryto transmit one or more downlink control messages to the communications device providing an indication of a first downlink communications resource of a wireless access interface from which the communications device can receive first downlink data, an indication of a second downlink communications resource of the wireless access interface from which the communications device can receive second downlink data, and an indication of a one or more allocations of an uplink communications resource of the wireless access interface for the communications device to transmit a first automatic repeat request-type, HARQ, feedback message for indicating whether or not the first downlink data is received and to transmit a second automatic repeat request-type feedback message for indicating whether or not the second downlink data is received, and the controller circuitry is configuredto identify that the first downlink communications resource and the second downlink communications resource of the wireless access interface overlap in time, andto receive either the first HARQ feedback message in the granted uplink communications resource indicating whether or not the first downlink data was received, orto receive the second HARQ feedback message in the granted uplink communications resource to indicate whether or not the second downlink data was received, andto identify from either the received first HARQ feedback message that the second downlink data was not received or from the received second HARQ feedback message that the first downlink data was not received.

Paragraph 24. Circuitry for receiving data from a wireless communications network, the circuitry comprisingreceiver circuitry configured to receive signals transmitted via a wireless access interface provided by the wireless communications network,transmitter circuitry configured to transmit signals via the wireless access interface, andcontroller circuitry configured to control the receiver circuitryto receive one or more downlink control messages providing a grant of a first downlink communications resource of the wireless access interface from which the communications device can receive first downlink data, a grant of a second downlink communications resource of the wireless access interface from which the communications device can receive second downlink data, and a grant of a one or more allocations of an uplink communications resource of the wireless access interface for the communications device to transmit a first automatic repeat request-type, HARQ, feedback message for indicating whether or not the first downlink data is received and to transmit a second automatic repeat request-type feedback message for indicating whether or not the second downlink data is received, the controller circuitry being configuredto detect that the first downlink communications resource and the second downlink communications resource of the wireless access interface overlap in time,to apply one or more predetermined criteria to determine whether the communications device can transmit one or both of the first HARQ feedback message on the allocated uplink communications resource and the second HARQ feedback message on the allocated uplink communications resource, andto control the receiver circuitry in accordance with the applied predetermined criteria to receive one or both of the first downlink data and the second downlink data, and to control the transmitter circuitryto transmit the determined HARQ feedback message for one or both of the received first and second downlink data.

Paragraph 25. Circuitry for receiving data from a wireless communications network, the circuitry comprisingreceiver circuitry configured to receive signals transmitted via a wireless access interface provided by the wireless communications network,transmitter circuitry configured to transmit signals via the wireless access interface, andcontroller circuitry configured to control the receiver circuitryto receive one or more downlink control messages providing a grant of a first downlink communications resource of a wireless access interface from which the communications device can receive first downlink data, a grant of a second downlink communications resource of the wireless access interface from which the communications device can receive second downlink data, and information of a one or more allocations of an uplink communications resource of the wireless access interface for the communications device to transmit a first hybrid automatic repeat request-type, HARQ, feedback message for indicating whether or not the first downlink data is correctly received, and information of a one or more allocations of an uplink communications resource of the wireless access interface for the communications device to transmit a second HARQ feedback message for indicating whether or not the second downlink data is correctly received, the controller circuitry being configuredto detect that the first downlink communications resource and the second downlink communications resource of the wireless access interface overlap in time, andto apply one or more predetermined criteria to determine whether the communications device can transmit HARQ feedback message for one or both of the first HARQ feedback message for transmission on the first uplink communications resources or the second HARQ feedback message for transmission on the second uplink communications resources, and to control the receiver circuitryto receive one or both of the first downlink data from the first downlink communications resources and the second downlink data from the second downlink communications resources, andin accordance with the determined conditions if it has been determined to transmit the first HARQ feedback message via the first uplink communications resources, to adapt the first HARQ feedback message transmitted on the first uplink communications resources to provide an indication of the second HARQ feedback for the second downlink data, or if it has been determined to transmit the second HARQ feedback message via the second uplink communications resources, to adapt the second HARQ feedback message transmitted on the second uplink communications resources to provide an indication of the first HARQ feedback for the first downlink data.

Paragraph 26. Circuitry forming part of a wireless communications network, the circuitry comprisingreceiver circuitry configured to receive signals transmitted from one or more communications devices via a wireless access interface provided by the wireless communications network,transmitter circuitry configured to transmit signals to the one or more communications devices via the wireless access interface, andcontroller circuitry configured to control the transmitter circuitryto transmit one or more downlink control messages to the communications device providing an indication of a first downlink communications resource of a wireless access interface from which the communications device can receive first downlink data, an indication of a second downlink communications resource of the wireless access interface from which the communications device can receive second downlink data, and an indication of a one or more allocations of an uplink communications resource of the wireless access interface for the communications device to transmit a first automatic repeat request-type, HARQ, feedback message for indicating whether or not the first downlink data is received and to transmit a second automatic repeat request-type feedback message for indicating whether or not the second downlink data is received, and the controller circuitry is configuredto identify that the first downlink communications resource and the second downlink communications resource of the wireless access interface overlap in time, andto receive either the first HARQ feedback message in the granted uplink communications resource indicating whether or not the first downlink data was received, orto receive the second HARQ feedback message in the granted uplink communications resource to indicate whether or not the second downlink data was received, andto identify from either the received first HARQ feedback message that the second downlink data was not received or from the received second HARQ feedback message that the first downlink data was not received.

Further particular and preferred aspects of the present invention are set out in the accompanying independent and dependent claims. It will be appreciated that features of the dependent claims may be combined with features of the independent claims in combinations other than those explicitly set out in the claims.

REFERENCES

[1] RP-182090, “Revised SID: Study on NR Industrial Internet of Things (IoT),” RAN #81.[2] Holma H. and Toskala A, “LTE for UMTS OFDMA and SC-FDMA based radio access”, John Wiley and Sons, 2009[3] 3GPP TS 38.321, “Medium Access Control (MAC) protocol specification (Rel-15)”, v15.3.0[4] 3GPP TS 38.214 “NR; Physical layer procedures for data (Release 15)”, version 15.2.0[5] R2-1818795, “LS on Intra-UE Prioritization/Multiplexing,” RAN2, RAN2 #104[6] RP-182089, “Study on physical layer enhancements for NR ultra-reliable and low latency communication (URLLC),” Huawei, HiSilicon, Nokia, Nokia Shanghai Bell, RAN #81[7] RP-190726, “New WID: Physical Layer Enhancements for NR Ultra-Reliable and Low Latency Communication (URLLC),” Huawei, HiSilicon, RAN #83[8] 3GPP TR38.824, “Study on physical layer enhancements for NR ultra-reliable and low latency ca se (URLLC) (Rel-16)”, v1.2.0[9] European patent application 19166662.7 “HARQ-ACK Prioritisation for multiple HARQ-ACK codebook”
Annex 1
LTE Wireless Access Interface

Embodiments of the present technique are not limited to a particular wireless communications standard, but find general application with a mobile communications system in which a transmitter and a receiver are configured to communicate data in units, transport blocks or packets for which some indication of feedback is provided as part of an ARQ type protocol. However, the following example embodiments will be explained with reference to a 3GPP defined LTE architecture. Those acquainted with LTE will appreciate that a wireless access interface configured in accordance with an LTE standard uses an orthogonal frequency division modulation (OFDM) based wireless access interface for the radio downlink (so-called OFDMA) and a single carrier frequency division multiple access scheme (SC-FDMA) on the radio uplink. The down-link and the up-link of a wireless access interface according to an LTE standard is presented inFIGS.17and18.

FIG.18provides a simplified schematic diagram of the structure of a downlink of a wireless access interface that may be provided by or in association with the eNB ofFIG.1when the communications system is operating in accordance with the LTE standard. In LTE systems the wireless access interface of the downlink from an eNB to a UE is based upon an orthogonal frequency division multiplexing (OFDM) access radio interface. In an OFDM interface the resources of the available bandwidth are divided in frequency into a plurality of orthogonal subcarriers and data is transmitted in parallel on a plurality of orthogonal subcarriers, where bandwidths between 1.4 MHZ and 20 MHz bandwidth may be divided into orthogonal subcarriers. Not all of these subcarriers are used to transmit data (some are used to carry reference information used for channel estimation at the receiver for example) whilst some at the edge of the band are not used at all. For LTE, the number of subcarriers varies between 72 subcarriers (1.4 MHz) and 1200 subcarriers (20 MHz), but it will be appreciated that for other wireless access interfaces, such as NR or 5G, the number of sub-carriers and the bandwidth may be different. In some examples the subcarriers are grouped on a basis of 2n, for example 128 to 2048, so that both a transmitter and a receiver can use an inverse and a forward Fast Fourier Transform to convert the sub-carriers from the frequency domain to the time domain and from the time domain to the frequency domain respectively. Each subcarrier bandwidth may take any value but in LTE it is fixed at 15 kHz.

As shown inFIG.18, the resources of the wireless access interface are also temporally divided into frames where a frame200lasts 10 ms and is subdivided into 10 sub-frames1201each with a duration of 1 ms. Each sub-frame201is formed from 14 OFDM symbols and is divided into two slots1220,1222each of which comprise six or seven OFDM symbols depending on whether a normal or extended cyclic prefix is being utilised within OFDM symbols for the reduction of inter symbol interference. The resources within a slot may be divided into resources blocks1203each comprising 12 subcarriers for the duration of one slot and the resource blocks are further divided into resource elements1204which span one subcarrier for one OFDM symbol, where each rectangle1204represents a resource element. The resource elements distributed in time within a sub-frame and frequency across the host system bandwidth represent the communications resources of the host system.

The simplified structure of the downlink of an LTE wireless access interface presented inFIG.14, also includes an illustration of each sub-frame1201, which comprises a control region1205for the transmission of control data, a data region1206for the transmission of user data and reference signals207which are interspersed in the control and data regions in accordance with a predetermined pattern. The control region1205may contain a number of physical channels for the transmission of control data, such as a physical downlink control channel (PDCCH), a physical control format indicator channel (PCFICH) and a physical HARQ indicator channel (PHICH). The data region may contain a number of physical channels for the transmission of data or control, such as a physical downlink shared channel (PDSCH), enhanced physical downlink control channel (ePDCCH) and a physical broadcast channel (PBCH). Although these physical channels provide a wide range of functionality to LTE systems, in terms of resource allocation and the present disclosure, PDCCH and PDSCH are most relevant. Further information on the structure and functioning of the physical channels of LTE systems can be found in [1].

Resources within the PDSCH may be allocated by an eNodeB to UEs being served by the eNodeB. For example, a number of resource blocks of the PDSCH may be allocated to a UE in order that it may receive data that it had previously requested or data which is being pushed to it by the eNodeB, such as radio resource control (RRC) signalling. InFIG.14, UE1 has been allocated resources1208of the data region1206, UE2 resources1209and UE3 resources1210. UEs in an LTE system may be allocated a fraction of the available resources for the PDSCH and therefore UEs are required to be informed of the location of their allocated resources within the PDSCH so that only relevant data within the PDSCH is detected and estimated. In order to inform the UEs of the location of their allocated communications resource elements, resource control information specifying downlink resource allocations is conveyed across the PDCCH in a form termed downlink control information (DCI), where resource allocations for a PDSCH are communicated in a preceding PDCCH instance in the same sub-frame.

FIG.19provides a simplified schematic diagram of the structure of an uplink of an LTE wireless access interface that may be provided by or in association with the eNodeB ofFIG.1. In LTE networks the uplink wireless access interface is based upon a single carrier frequency division multiplexing FDM (SC-FDM) interface and downlink and uplink wireless access interfaces may be provided by frequency division duplexing (FDD) or time division duplexing (TDD), where in TDD implementations sub-frames switch between uplink and downlink sub-frames in accordance with predefined patterns. However, regardless of the form of duplexing used, a common uplink frame structure is utilised. The simplified structure ofFIG.3illustrates such an uplink frame in an FDD implementation. A frame1300is divided into 10 sub-frames1301of 1 ms duration where each sub-frame1301comprises two slots1302of 0.5 ms duration. Each slot1302is then formed from seven OFDM symbols1303where a cyclic prefix304is inserted between each symbol in a manner equivalent to that in downlink sub-frames.

As shown inFIG.19, each LTE uplink sub-frame may include a plurality of different channels, for example a physical uplink communications channel (PUSCH)1305, a physical uplink control channel (PUCCH)1306, and a physical random access channel (PRACH). The physical Uplink Control Channel (PUCCH) may carry control information such as ACK/NACK to the eNodeB for downlink transmissions, scheduling request indicators (SRI) for UEs wishing to be scheduled uplink resources, and feedback of downlink channel state information (CSI) for example. The PUSCH may carry UE uplink data or some uplink control data. Resources of the PUSCH are granted via PDCCH, such a grant being typically triggered by communicating to the network the amount of data ready to be transmitted in a buffer at the UE. The PRACH may be scheduled in any of the resources of an uplink frame in accordance with a one of a plurality of PRACH patterns that may be signalled to UE in downlink signalling such as system information blocks. As well as physical uplink channels, uplink sub-frames may also include reference signals. For example, demodulation reference signals (DMRS)1307and sounding reference signals (SRS)1308may be present in an uplink sub-frame where the DMRS occupy the fourth symbol of a slot in which PUSCH is transmitted and are used for decoding of PUCCH and PUSCH data, and where SRS are used for uplink channel estimation at the eNodeB. The ePDCCH channel carries similar control information (DCI) as the PDCCH, but the physical aspects of PDCCH are different to those of ePDCCH, as discussed elsewhere herein. Further information on the structure and functioning of the physical channels of LTE systems can be found in [1].

In an analogous manner to the resources of the PDSCH, resources of the PUSCH are required to be scheduled or granted by the serving eNodeB and thus if data is to be transmitted by a UE, resources of the PUSCH are required to be granted to the UE by the eNodeB. At a UE, PUSCH resource allocation is achieved by the transmission of a scheduling request or a buffer status report to its serving eNodeB. The scheduling request may be made, when there is insufficient uplink resource for the UE to send a buffer status report, via the transmission of Uplink Control Information (UCI) on the PUCCH when there is no existing PUSCH allocation for the UE, or by transmission directly on the PUSCH when there is an existing PUSCH allocation for the UE. In response to a scheduling request, the eNodeB is configured to allocate a portion of the PUSCH resource to the requesting UE sufficient for transferring a buffer status report and then inform the UE of the buffer status report resource allocation via a DCI in the PDCCH. Once or if the UE has PUSCH resource adequate to send a buffer status report, the buffer status report is sent to the eNodeB and gives the eNodeB information regarding the amount of data in an uplink buffer or buffers at the UE. After receiving the buffer status report, the eNodeB can allocate a portion of the PUSCH resources to the sending UE in order to transmit some of its buffered uplink data and then inform the UE of the resource allocation via a DCI in the PDCCH. For example, presuming a UE has a connection with the eNodeB, the UE will first transmit a PUSCH resource request in the PUCCH in the form of a UCI. The UE will then monitor the PDCCH for an appropriate DCI, extract the details of the PUSCH resource allocation, and transmit uplink data, at first comprising a buffer status report, and/or later comprising a portion of the buffered data, in the allocated resources.

Although similar in structure to downlink sub-frames, uplink sub-frames have a different control structure to downlink sub-frames, in particular the upper1309and lower1310subcarriers/frequencies/resource blocks of an uplink sub-frame are reserved for control signalling rather than the initial symbols of a downlink sub-frame. Furthermore, although the resource allocation procedure for the downlink and uplink are relatively similar, the actual structure of the resources that may be allocated may vary due to the different characteristics of the OFDM and SC-FDM interfaces that are used in the downlink and uplink respectively. In OFDM each subcarrier is individually modulated and therefore it is not necessary that frequency/subcarrier allocation are contiguous however, in SC-FDM subcarriers are modulated in combination and therefore if efficient use of the available resources are to be made, contiguous frequency allocations for each UE may be preferable.