WO2022152546A1

WO2022152546A1 - Communications device, infrastructure equipment and methods

Info

Publication number: WO2022152546A1
Application number: PCT/EP2021/087542
Authority: WO
Inventors: Shin Horng Wong; Naoki Kusashima; Martin Warwick Beale; Yassin Aden Awad
Original assignee: Sony Group Corporation; Sony Europe B.V.
Priority date: 2021-01-18
Filing date: 2021-12-23
Publication date: 2022-07-21
Also published as: CN116746091A; DE112021006835T5; JP2024505403A

Abstract

A method of transmitting control information by a communications device in a wireless communications network, the method comprising receiving from an infrastructure equipment of athe wireless communications network an indication of a plurality of instances of downlink communications resources associated with a semi-persistent resource allocation, the plurality of instances of downlink communications resources allocated for the transmission of data by the infrastructure equipment to the communications device via a wireless access interface, determining that uplink communication resources allocated for the transmission of a first portion of acknowledgement information are invalid and cannot be used for the transmission of the first portion of acknowledgement information, the first portion of acknowledgement information indicating an acknowledgement status of a respective instance of the downlink communication resources, in response to determining that the uplink communication resources allocated for the transmission of the first portion of acknowledgement information are invalid, selecting second uplink communication resources, and transmitting the first portion of acknowledgement information using the selected second uplink communication resources.

Description

COMMUNICATIONS DEVICE, INFRASTRUCTURE EQUIPMENT AND METHODS

BACKGROUND

Field

The present disclosure relates to communications devices, infrastructure equipment and methods for the transmission of control information in a wireless communications network. The present disclosure claims the Paris Convention priority from European patent application number EP21152203.2, the contents of which are incorporated by reference in their entirety into the present disclosure.

Description of Related Art

The “background” description provided herein is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it is described in this background section, as well as aspects of the description which may not otherwise qualify as prior art at the time of filing, are neither expressly or impliedly admitted as prior art against the present invention.

Third and fourth generation mobile telecommunication systems, such as those based on the 3GPP defined UMTS and Long Term Evolution (LTE) architecture, are able to support more sophisticated services than simple voice and messaging services offered by previous generations of mobile telecommunication systems. For example, with the improved radio interface and enhanced data rates provided by LTE systems, a user is able to enjoy high data rate applications such as mobile video streaming and mobile video conferencing that would previously only have been available via a fixed line data connection. The demand to deploy such networks is therefore strong and the coverage area of these networks, i.e. geographic locations where access to the networks is possible, may be expected to increase ever more rapidly.

Future wireless communications networks will be expected to support communications routinely and efficiently with a wider range of devices associated with a wider range of data traffic profiles and types than current systems are optimised to support. For example, it is expected future wireless communications networks will be expected to efficiently support communications with devices including reduced complexity devices, machine type communication (MTC) devices, high resolution video displays, virtual reality headsets and so on. Some of these different types of devices may be deployed in very large numbers, for example low complexity devices for supporting the “The Internet of Things”, and may typically be associated with the transmissions of relatively small amounts of data with relatively high latency tolerance.

In view of this there is expected to be a desire for future wireless communications networks, for example those which may be referred to as 5G or new radio (NR) system / new radio access technology (RAT) systems [1], as well as future iterations / releases of existing systems, to efficiently support connectivity for a wide range of devices associated with different applications and different characteristic data traffic profiles.

There remains, however a technical challenge to be addressed to ensure that control information can be transmitted from a communications device to an infrastructure equipment in a timely manner while making efficient using the resources of a wireless access interface.

SUMMARY

The present disclosure can help address or mitigate at least some of the issues discussed above.

Respective aspects and features of the present disclosure are defined in the appended claims. It is to be understood that both the foregoing general description and the following detailed description are exemplary, but are not restrictive, of the present technology. The described embodiments, together with further advantages, will be best understood by reference to the following detailed description taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete appreciation of the disclosure and many of the attendant advantages thereof will be readily obtained as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein like reference numerals designate identical or corresponding parts throughout the several views, and:

Figure 1 schematically represents some aspects of an LTE-type wireless telecommunication system which may be configured to operate in accordance with certain embodiments of the present disclosure;

Figure 2 schematically represents some aspects of a new radio access technology (RAT) wireless telecommunications system which may be configured to operate in accordance with certain embodiments of the present disclosure;

Figure 3 is a schematic block diagram of an example infrastructure equipment and communications device configured in accordance with example embodiments;

Figure 4 illustrates the transmission of acknowledgement information associated with downlink transmissions, where the downlink transmissions use dynamically allocated communication resources, in accordance with conventional techniques;

Figure 5 illustrates the transmission of acknowledgement information associated with downlink transmissions of eURLLC data, where resources for the transmission of the acknowledgement information are allocated within a sub-slot, in accordance with conventional techniques;

Figure 6 shows the multiplexing of multiple portions of acknowledgement information associated with respective downlink resource instances within a single instance of resources of an uplink control channel, in accordance with conventional techniques.

Figure 7 shows the use of a subsequent allocation of control channel resources for the transmission of acknowledgement information which could not be transmitted in an earlier control channel allocation, because the earlier control channel allocation comprised timeslots not designated for uplink transmission, in accordance with certain proposals;

Figure 8, Figure 9, Figure 10, Figure 11 and Figure 12 illustrate additional communication resources selected in response to an identification of an invalid instance of control channel resources, in accordance with embodiments of the present technique;

Figure 13 illustrates additional communication resources selected in response to an identification of an invalid instance of control channel resources in accordance with embodiments of the present technique, wherein the additional communication resources comprise a plurality of resource instances;

Figure 14 illustrates additional communication resources selected in response to an identification of an invalid instance of control channel resources in accordance with embodiments of the present technique, wherein the additional communication resources comprise a plurality of resource instances and where one or more resource instances is not used if it is possible to transmit selected acknowledgement information without using all valid resource instances; Figure 15 illustrates additional communication resources selected in response to an identification of an invalid instance of control channel resources in accordance with embodiments of the present technique, wherein the additional communication resources comprise a plurality of resource instances and where the number of such resource instances is indicated by the reception of a termination indication; and

Figure 16 is a flow chart for a process which may be carried out by a communications device in accordance with embodiments of the present technique.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Long Term Evolution Advanced Radio Access Technology (4G)

Figure 1 provides a schematic diagram illustrating some basic functionality of a mobile telecommunications network / system 100 operating 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 of Figure 1 and certain aspects of their respective modes of operation are well-known and defined in the relevant standards administered by the 3GPP (RTM) 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 network 100 includes a plurality of base stations 101 connected to a core network part 102. Each base station provides a coverage area 103 (e.g. a cell) within which data can be communicated to and from communications devices 104. Data is transmitted from the base stations 101 to the communications devices 104 within their respective coverage areas 103 via a radio downlink. Data is transmitted from the communications devices 104 to the base stations 101 via a radio uplink. The core network part 102 routes data to and from the communications devices 104 via the respective base stations 101 and 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)

Figure 2 is a schematic diagram illustrating a network architecture for a new RAT wireless communications network / system 200 based on previously proposed approaches which may also be adapted to provide functionality in accordance with embodiments of the disclosure described herein. The new RAT network 200 represented in Figure 2 comprises a first communication cell 201 and a second communication cell 202. Each communication cell 201, 202, comprises a controlling node (centralised unit) 221, 222 in communication with a core network component 210 over a respective wired or wireless link 251, 252. The respective controlling nodes 221, 222 are also each in communication with a plurality of distributed units (radio access nodes / remote transmission and reception points (TRPs)) 211, 212 in their respective cells. Again, these communications may be over respective wired or wireless links. The distributed units 211, 212 are responsible for providing the radio access interface for communications devices connected to the network. Each distributed unit 211, 212 has a coverage area (radio access footprint) 241, 242 where 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 cells 201, 202. Each distributed unit 211, 212 includes transceiver circuitry for transmission and reception of wireless signals and processor circuitry configured to control the respective distributed units 211, 212.

In terms of broad top-level functionality, the core network component 210 of the new RAT communications network represented in Figure 2 may be broadly considered to correspond with the core network 102 represented in Figure 1, and the respective controlling nodes 221, 222 and their associated distributed units / TRPs 211, 212 may be broadly considered to provide functionality corresponding to the base stations 101 of Figure 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 UE 260 is represented in Figure 2 within the coverage area of the first communication cell 201. This communications device 260 may thus exchange signalling with the first controlling node 221 in the first communication cell via one of the distributed units 211 associated with the first communication cell 201. 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 of Figure 2, two communication cells 201, 202 and one communications device 260 are 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 that Figure 2 represents 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 in Figures 1 and 2. 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 station 101 as shown in Figure 1 which 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 node 221, 222 and / or a TRP 211, 212 of the kind shown in Figure 2 which is adapted to provide functionality in accordance with the principles described herein.

A more detailed illustration of a communications device 270 and an example network infrastructure equipment 272, which may be thought of as a gNB 101 or a combination of a controlling node 221 and TRP 211, is presented in Figure 3. As shown in Figure 3, the communications device 270 is shown to transmit uplink data to the infrastructure equipment 272 of a wireless access interface as illustrated generally by an arrow 274. The UE 270 is shown to receive downlink data transmitted by the infrastructure equipment 272 via resources of the wireless access interface as illustrated generally by an arrow 288. As with Figures 1 and 2, the infrastructure equipment 272 is connected to a core network 276 (which may correspond to the core network 102 of Figure 1 or the core network 210 of Figure 2) via an interface 278 to a controller 280 of the infrastructure equipment 272. The infrastructure equipment 272 may additionally be connected to other similar infrastructure equipment by means of an inter-radio access network node interface, not shown on Figure 3.

The infrastructure equipment 272 includes a receiver 282 connected to an antenna 284 and a transmitter 286 connected to the antenna 284. Correspondingly, the communications device 270 includes a controller 290 connected to a receiver 292 which receives signals from an antenna 294 and a transmitter 296 also connected to the antenna 294.

The controller 280 is configured to control the infrastructure equipment 272 and 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 controller 280 may comprise circuitry which is suitably configured / programmed to provide the desired functionality using conventional programming / configuration techniques for equipment in wireless telecommunications systems. The transmitter 286 and the receiver 282 may comprise signal processing and radio frequency filters, amplifiers and circuitry in accordance with conventional arrangements. The transmitter 286, the receiver 282 and the controller 280 are schematically shown in Figure 3 as 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 equipment 272 will in general comprise various other elements associated with its operating functionality.

Correspondingly, the controller 290 of the communications device 270 is configured to control the transmitter 296 and the receiver 292 and 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 controller 290 may 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 transmitter 296 and the receiver 292 may comprise signal processing and radio frequency filters, amplifiers and circuitry in accordance with conventional arrangements. The transmitter 296, receiver 292 and controller 290 are schematically shown in Figure 3 as 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 device 270 will 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 in Figure 3 in the interests of simplicity.

The controllers 280, 290 may be configured to carry out instructions which are stored on a computer readable medium, such as a non-volatile memory. The processing steps described herein may be carried out by, for example, a microprocessor in conjunction with a random-access memory, which may be nonvolatile memory, operating according to instructions stored on a computer readable medium.

Two of the services defined in 5G are the Ultra-Reliable and Low Latency Communications (URLLC) and the enhanced Mobile BroadBand (eMBB) services. URLLC has very low latency and high reliability where a URLLC data packet (e.g. 32 bytes) is required to be transmitted from the radio protocol layer 2/3 SDU ingress point to the radio protocol layer 2/3 SDU egress point of the radio interface within 1 ms with a reliability of 99.999% [3] to 99.9999%. On the other hand, eMBB requires high data rate, e.g. 20 Gbps with moderate latency and reliability (e.g. 99% to 99.9%).

3GPP has recently completed a Rel-16 Work Item (WI) on eURLLC [4] which specifies features for high reliability and low latency services such as factory automation, transport industry, electrical power distribution, etc. in a 5G system. The eURLLC feature is further enhanced in a new Rel-17 WI [5] where one of the objectives is to enhance HARQ-ACK feedbacks for PDSCH transmissions.

Where communication resources are allocated by means of a dynamic grant, downlink control information is transmitted to the communications device to indicate the allocated communication resources and parameters for determining the uplink resources for transmitting acknowledgement information indicating whether the data transmitted using the allocated resources had been correctly received or not.

The uplink resources for transmitting acknowledgement information may be allocated on a physical uplink control channel (PUCCH).

The same PUCCH resources may be used for the transmission of acknowledgement information associated with multiple downlink transmissions.

Figure 4 illustrates the transmission of acknowledgement information associated with downlink transmissions, where the downlink transmissions use dynamically allocated communication resources, in accordance with conventional techniques.

In Figure 4, time progresses from left to right. Communications resources of a wireless access interface are shown, comprising downlink resources 404 and uplink resources 402. The uplink transmission 274 of Figure 3 may be an example of a transmission using uplink resources 402. The downlink transmission 288 of Figure 3 may be an example of a transmission using downlink resources 404. In the time domain, the communication resources are divided into timeslots (n, n+1, etc.), each timeslot comprising symbol periods. In the example of Figure 4, each timeslot contains 14 symbol periods.

Downlink control information (DCI) 410a, 410b, 410c allocates corresponding downlink communication resources 412a, 412b, 412c. The downlink communication resources 412a, 412b, 412c are used for the transmission of data on physical downlink shared channels (PDSCH).

Each DCI comprises an indication of a value of a parameter KI. The KI parameter indicates a timeslot offset between a timeslot in which the downlink PDSCH resources 412a, 412b, 412c end and a timeslot in which communication resources are allocated for the transmission of associated acknowledgement information. For example, the value of KI may be indicated in a “PDSCH-to-HARQ_feedback timing indicator” field of the DL Grant. The downlink grant may be encoded in accordance with a conventional DCI format, such as a DCI Format 1 0 , DCI Format 1 1 or DCI Format 1 2.

In the example of Figure 4, a first DCI 410a in slot n allocates first communication resources 412a which begin and end in slot n+1, and indicates a KI value of 3. Accordingly, the acknowledgment information associated with the downlink transmission (i.e. indicating whether the data transmitted via the first communication resources 412a were correctly received and decoded) is to be transmitted in slot n+l+Kl = n+4. Similarly, second and third DCIs 410b, 410c, allocate respective second and third communication resources 412b, 412c, starting and ending in timeslots n+2 and n+3 respectively and indicate KI values of 2 and 1, respectively. Accordingly, a communications device is able to determine that acknowledgment information associated with the second and third downlink transmissions in second and third communication resources 412b, 412c is also to be transmitted in slot n+4.

In accordance with conventional techniques, acknowledgement information may be transmitted as part of a hybrid automatic repeat-request acknowledgement (HARQ) process.

In the present disclosure, the term ‘HARQ-ACK’ (hybrid automatic repeat-request acknowledgement) is used to refer to a portion of acknowledgement information indicating whether data transmitted via a single instance of downlink communication resources has been correctly received and decoded. It will be appreciated that the techniques disclosed herein are applicable when acknowledged data transmission is carried out other than by means of a HARQ technique. In the example of Figure 4, there may be three separate HARQ-ACKs, one each associated with the first to third downlink communication resources 412a, 412b, 412c. Where no multiplexing is carried out (as described further below), a HARQ-ACK may comprise acknowledgement information which would have been sent using a single instance of allocated PUCCH resources.

In accordance with conventional techniques, such as those standardised in 3GPP Release 15, a communications device is permitted to transmit HARQ-ACKs using at most one PUCCH resource within any given timeslot, even if it has been allocated multiple PUCCH resources which do not overlap in time. (This constraint may not apply to the use of further PUCCH resources for other purposes, such as transmitting a scheduling request).

The communications device may resolve this constraint by multiplexing the HARQ-ACKs, such that they may be sent using a single PUCCH resource instance. That is, the single PUCCH resource instance is used to transmit the multiple HARQ-ACKs. Multiplexing may comprise combining the HARQ-ACKs in a manner suitable for transmission using the single PUCCH resource instance. For example, this may comprise concatenating the acknowledgement information of the HARQ-ACKs.

A multiplexing window may be defined, whereby HARQ-ACKs may be multiplexed together only if they relate to downlink communications which occur within the multiplexing window. In the example of Figure 4, the PUCCH multiplexing window 420 extends from, and includes slot n to slot n+3. Because each of the first to third downlink communication resources 412a, 412b, 412c are within the multiplexing window 420, the communications device is permitted to multiplex the corresponding HARQ-ACKs.

PUCCH resources may be indicated in a “PUCCH Resource Indicator” (PRI) field in a DU Grant (e.g. DCI). The communications device may select the PUCCH resources based on the PRI indicated by the last (i.e. most recently received) DCI which allocated downlink communication resources within the multiplexing window. In the example of Figure 4, the third DCI 410c indicates PUCCH resources 414. Accordingly, in the example of Figure 4, the communications device selects the PUCCH resources 414, generates a multiplexed HARQ-ACK, based on the three HARQ-ACKs associated with the first to third downlink communication resources 412a, 412b, 412c, and transmits the multiplexed HARQ-ACK using the PUCCH resources 414 within timeslot n+4. As described above, the PUCCH resources 414 selected for the transmission of the multiplex HARQ-ACK may be selected because the PUCCH resources 414 are indicated by the last DCI (third DCI 410c) in the multiplexing window.

In some examples, each of the three DCIs 410a, 410b, 410c may allocate the same PUCCH resources 414 within the timeslot n+4. However, in some examples two or more PUCCH resources (not shown in Figure 4) may be allocated by the three DCIs 410a, 410b, 410c. Even if the communications device has been allocated multiple PUCCH resources which do not overlap in time, the communications device may be restricted to transmitting HARQ-ACKs using at most one PUCCH resource within any given timeslot. Therefore, one of the allocated PUCCH resources may be selected for the transmission of the HARQ- ACKs. In the example of Figure 4, this is the PUCCH resources 414 allocated by the last (i.e. most recently received) DCI which allocated downlink communication resources within the multiplexing window.

In accordance with conventional techniques, such as those standardised in 3GPP Release 16, the time domain may be further divided into sub-slots, where each timeslot contains a number (such as 2 or 7) of sub-slots. A communications device may be permitted to transmit HARQ-ACKs using more than one PUCCH resource within a timeslot, if the PUCCH resources occur within different sub-slots. A KI value indicated by a DCI may accordingly indicate a sub-slot in which a HARQ-ACK is to be transmitted.

Figure 5 illustrates the transmission of acknowledgement information associated with downlink transmissions, where resources for the transmission of the acknowledgement information are allocated within a sub-slot, in accordance with conventional techniques.

In the example of Figure 5, there are two sub-slots, each of 7 symbol periods in duration, within each slot. The sub-slots are labelled m, m+I, m+2, etc.

The first DCI 510a allocates first downlink communication resources 512a and indicates that KI has a value of 6. Because the first downlink communication resources 512a end in sub-slot m+2, the first HARQ-ACK is to be transmitted in first PUCCH resources 514a in sub-slot m+2 + 6 = m+8. Similarly, the second DCI 510b allocates second downlink communication resources 512b and indicates that KI has a value of 4. Because the second downlink communication resources 512b end in sub-slot m+5, the second HARQ-ACK is to be transmitted in second PUCCH resources 514b in sub-slot m+5 + 4 = m+9. Because the first and second PUCCH resources 514a, 514b are in different sub-slots, the communications device is permitted to (and indeed, does) transmit respective HARQ-ACKs using the first and second PUCCH resources 514a, 514b.

Conventionally, semi-persistent scheduling (SPS) comprises the allocation of periodic communication resource instances for the transmission of data to, or by, a particular communications device. An indication of an SPS allocation may be transmitted using RRC configuration signalling. An SPS allocation may be subsequently activated or deactivated.

When activated, each instance (referred to herein as an SPS instance) of the SPS allocation is preallocated, and there is no need for a separate downlink grant to be transmitted for each instance. SPS can therefore permit efficient use of communication resources when data is to be transmitted periodically, and/or with very low latency and reduced control overhead. A communications device or infrastructure equipment may not be required to transmit using every allocated SPS instance. However, in accordance with conventional techniques, a communications device may be required to transmit acknowledgement information in respect of each downlink SPS instance allocated for the transmission of data to the communications device, regardless of whether or not any such transmission occurred.

A particular downlink SPS allocation may allocate resources on a physical downlink shared channel (PDSCH), and accordingly, such an allocation and the corresponding sequence of SPS instances is referred to herein as an SPS PDSCH. It will be appreciated, however, that an SPS allocation may allocate resources on other channels.

In accordance with conventional techniques such as those specified in 3GPP Release 15 specifications, a communications device can be configured with at most one SPS PDSCH. After configuration, the SPS PDSCH may be activated by the transmission of an activation DCI by the infrastructure equipment to the communications device. An activation DCI may be encoded in accordance with a conventional DCI Format 1 0 or DCI Format 1 1. The SPS PDSCH may be deactivated by the transmission of a deactivation DCI by the infrastructure equipment to the communications device. A cyclic redundancy check (CRC) of an activation DCI and a deactivation DCI may be scrambled with an identifier associated with the SPS PDSCH, such as a CS radio network temporary identity (CS-RNTI).

The communications device may be required to transmit acknowledgement information to confirm the receipt of a deactivation DCI. On the other hand, no acknowledgement information may be required to confirm the receipt of an activation DCI.

The activation DCI may comprise a PDSCH-to-HARQ_feedback timing indicator which indicates the value of KI for each subsequent instance of the SPS PDSCH, until the SPS PDSCH is deactivated. The KI value applicable to instances of the SPS PDSCH can only be changed by deactivating, and subsequently activating, the SPS PDSCH, the subsequent activation being by means of a further activation DCI comprising an indication of the updated KI value.

In accordance with the 3GPP Release 15 specifications, because a communications device can be configured with at most one SPS PDSCH, PUCCH formats which can carry at most 2 HARQ-ACKs (such as a PUCCH format 0 or a PUCCH format 1) may be used for the transmission of acknowledgement information associated with an SPS PDSCH instance. If it would not be possible to transmit the acknowledgement information (HARQ-ACK) because of a collision with a PUCCH allocation for the transmission of a HARQ-ACK associated with a PDSCH transmission which was dynamically granted (a “DG-PDSCH”), the SPS HARQ-ACK may be multiplexed with the conflicting HARQ-ACK, and transmitted using the PUCCH allocation for the transmission of a HARQ-ACK associated with the DG-PDSCH.

In accordance with conventional techniques such as those specified in 3GPP Release 16 specifications, a communications device can be configured with at most eight SPS PDSCHs. Each SPS PDSCH may be associated with an SPS Configuration Index, the mapping between SPS Configuration Index and SPS PDSCH being indicated by RRC configuration signalling.

Each SPS PDSCH may be individually activated using an activation DCI, the activation DCI comprising an indication of the associated SPS Configuration Index and an indication of the KI value for that SPS PDSCH. Multiple SPS PDSCHs may be deactivated using a single deactivation DCI. As in Release 15, activation DCIs and deactivation DCIs may have their CRC scrambled with the CS-RNTI, and acknowledgment information is required to be transmitted only in response to receiving a deactivation DCI.

It may be the case that multiple HARQ-ACKs corresponding to different SPS PDSCH instances are to be sent within a same slot or sub-slot, based on the timing of the SPS PDSCH instances and the associated KI values. In particular, the KI values may be different for different SPS PDSCHs.

In such a scenario, the communications device may multiplex the conflicting HARQ-ACKs such that they may be transmitted using a single PUCCH instance. To allow such multiplexing, PUCCH Formats 2, 3, and 4 may be used (in addition to PUCCH Formats 0 and 1).

The ordering of the HARQ-ACKs in the multiplexed transmission may be in accordance with a predetermined sequence. For example, the order of the HARQ-ACKs may be based on the SPS PDSCH Configuration index of the corresponding SPS PDSCH instances, and (where multiple HARQ-ACKs are associated with the same SPS PDSCH) based on the slot in which the corresponding SPS PDSCH instances occurred. Since the KI value may be fixed per SPS PDSCH, then it is unlikely that HARQ- ACKs associated with two or more SPS PDSCH having the same index would be multiplexed into a single PUCCH transmission.

Figure 6 shows the multiplexing of multiple HARQ-ACKs associated with respective SPS PDSCH instances within a single PUCCH instance, in accordance with conventional techniques.

Figure 6 shows SPS instances associated with three SPS PDSCHs, and two PUCCH instances.

Five instances 802a, 802b, 802c, 802d, 802e of a first SPS PDSCH having a KI value of 3 are shown. Three instances 804a, 804b, 804c of a second SPS PDSCH having a KI value of 4 are shown. A single instance 806 of a third SPS PDSCH having a KI value of 1 is also shown. No SPS PDSCH instances occur prior to slot n; for example, each of the first to third SPS PDSCHs may have been activated such that their first instance occurred during, or after, slot n.

Based on the KI value associated with the first SPS PDSCH, first PUCCH resources 808a in slot n+3 are allocated for the transmission of a HARQ-ACK associated with the first instance 802a of the first SPS PDSCH (which occurs in slot n). No other PUCCH resources are allocated for the transmission by the communications device of a HARQ-ACK for any other PDSCH instances during slot n+3. Accordingly, the communications device uses the first PUCCH resources 808a to transmit a HARQ-ACK associated with the first instance 802a of the first SPS PDSCH, as indicated by the dashed arrow 812.

Based on the KI values of the associated SPS PDSCHs, PUCCH resources (such as the second PUCCH resources 808b) are allocated in slot n+4 for the transmission of HARQ-ACKs associated with the first instance 804a of the second SPS PDSCH (which occurs in slot n), the second instance 802b of the first SPS PDSCH (which occurs in slot n+1), and the first instance 806 of the third SPS PDSCH (which occurs in slot n+3).

HARQ-ACKs for each of these three instances are therefore multiplexed and transmitted using the second PUCCH resources 808b, as indicated by the dashed arrows 810a, 810b, 810c.

In the example of Figure 4, Figure 5 and Figure 6, the wireless access interface operates in a frequency division duplex (FDD) manner, with separate communication resources 402, 404 (operating at different, non-overlapping, frequency ranges) for uplink (towards the infrastructure equipment) and downlink (by the infrastructure equipment), respectively. A wireless access interface may alternatively operate in a time division duplex (TDD) mode of operation. In TDD, communication resources within a single frequency range are used for uplink and downlink communications.

For example, where the communication resources are divided in time into slots, and each slot comprises a number of symbol periods, each symbol period may be designated for uplink use or for downlink use. In addition, in accordance with certain conventional techniques, a symbol period may be designated as ‘invalid’, that is, not available for either uplink or downlink transmission.

The designation of each symbol period may be carried out dynamically by the infrastructure equipment. A slot format indicator (SFI) may be transmitted by the infrastructure equipment to one or more communications device within a cell, to indicate the designation of future symbol periods.

Accordingly, PUCCH resources determined according to the principles described above may occur during (or comprise) timeslots which are not designated as uplink timeslots. Such PUCCH resources cannot be used for the transmission of any HARQ-ACK, and thus acknowledgement information associated with an earlier PDSCH instance may be delayed or not transmitted.

The problem of PUCCH resources overlapping with non-uplink symbol periods may be a particular problem where the PUCCH resources are associated with an SPS PDSCH. This is because the KI value for an SPS PDSCH may be signalled only when the SPS PDSCH is activated. This may be separated in time from a subsequent PUCCH instance which overlaps with a non-uplink symbol period. In contrast, the PRI and KI values for a dynamically granted PDSCH (and associated PUCCH) may be transmitted closer in time to the associated PUCCH, and it thus may be less likely that the associated PUCCH conflicts with a symbol period which is not designated as an uplink symbol period.

Accordingly, there is a need to address the potentially high probability that a PUCCH associated with an SPS PDSCH cannot be used for transmission by a communications device because it includes one or more resources which are not designated for uplink transmission. A consequence of a PUCCH not being used for transmission may include unnecessary retransmissions of downlink data, because the infrastructure equipment does not receive a confirmation that the downlink data had been correctly received.

It has been proposed that in order to overcome the above problem, an infrastructure equipment may transmit a downlink control information (DCI) allocating resources for the transmission of multiple HARQ-ACKs encoded using a Type 3 HARQ-ACK codebook. The procedure for allocating resources for the transmission of information using the Type 3 HARQ-ACK codebook has been introduced in 3GPP Release 16 specifications for the purpose of allowing the transmission of multiple HARQ-ACKs where earlier allocated resources are within unlicensed spectrum, but cannot be used because of an unsuccessful ‘listen-before-talk’ procedure (see e.g. section 9.1.4 of [9]).

Various modifications to the existing procedures for the use of a Type 3 HARQ-ACK codebook have been proposed [6], [7], to allow the transmission of HARQ-ACKs associated with an SPS PDSCH, where PUCCH resources associated with the SPS PDSCH could not be used for transmission because the PUCCH resources include symbol periods designated for uplink transmission or as invalid.

An example of the use of a Type 3 HARQ-ACK codebook transmission, in accordance with existing proposals is shown in Figure 7.

Figure 7 shows the use of a subsequent PUCCH allocation for the transmission of a HARQ-ACK which could not be transmitted in an earlier PUCCH allocation, because the earlier PUCCH allocation comprised timeslots not designated for uplink transmission, in accordance with certain proposals [6], [7], Figure 7 shows communications resources 902 of a wireless access interface operating in TDD mode, the communication resources being divided in time into five slots (labelled n, n+1, ... n+4), each slot comprising 14 symbol periods. Certain symbol periods (indicated by diagonal hatching) are designated as uplink symbols, and one symbol period (indicated by horizontal hatching) is designated as an invalid symbol. Other symbol periods are designated as downlink symbol periods; of these, some (indicated by diagonal hatching) may be used for the transmission of downlink control information using a physical downlink control channel (PDCCH).

An instance 904 of a first SPS PDSCH is shown in slot n. The KI value associated with the first SPS PDSCH is 1. According to the KI value for the first SPS PDSCH, a first PUCCH instance 908 for the transmission of a HARQ-ACK associated with the instance 904 of the first SPS PDSCH would occur in slot n+1. More specifically, in the example of Figure 7, the first PUCCH instance 908 would occur from time t6 to time t9. The determination of the specific PUCCH resources may be based, for example, on the PRI associated with the first SPS PDSCH. However, the time period from time t6 to time t9 includes a downlink symbol (from time t6 to time t7) and an invalid symbol (from time t7 to time t8).

Accordingly, as indicated by the superimposed ‘X’, it is not possible for the communications device to transmit the HARQ-ACK during the first PUCCH instance 908.

The infrastructure equipment may determine that the first PUCCH instance 908 could not be used by the communications device for the transmission of the HARQ-ACK, and in response may schedule a second PUCCH instance 914 from time tl 8 to time tl9. In order to indicate the allocation of these resources to the communications device, the infrastructure equipment transmits, from time tl2 to time tl 3, a DCI 912 which indicates the allocation of the second PUCCH instance 914.

In response to receiving the DCI 912, the communications device transmits the HARQ-ACK associated with the SPS PDSCH instance 904, using the second PUCCH instance 914.

The inventors of the present technique have identified various disadvantages of the proposed scheme. First, the allocation of the second PUCCH instance 914 requires the transmission of an additional DCI. This requires available PDCCH capacity. For example, referring to the example of Figure 7, it may not have been possible to transmit the second DCI earlier than time tl2, because the PDCCH resources from time t9 to time tlO may have been congested.

In addition, the use of additional PDCCH resources conflicts with a general goal of SPS allocation schemes (and similar periodic resource allocations) to minimize control signalling overhead.

Although the additional DCI 912 indicates only a single resource instance, it may need to be robustly encoded to ensure that it can be decoded reliably. Accordingly, the additional DCI 912 may require significant communication resources (e.g., in accordance with a PDCCH aggregation level 4, 8 or 16).

These disadvantages may generally increase the latency of transmission of the HARQ-ACK. This may in turn mean that either any required retransmissions of downlink data are similarly delayed, or are sent speculatively. Speculative (or pre-emptive) retransmissions may occur when the infrastructure equipment cannot determine, based on HARQ-ACK information, whether downlink data has been correctly received, but retransmits the data in any case. This may result in wasted communication resources.

There is therefore a need to provide a technical solution for providing an effective and efficient technique for transmitting HARQ-ACK information, particularly HARQ-ACK information associated with SPS PDSCH transmissions. Embodiments of the present technique can provide a method of transmitting control information by a communications device in a wireless communications network, the method comprising receiving from an infrastructure equipment of athe wireless communications network an indication of a plurality of instances of downlink communications resources associated with a semi-persistent resource allocation, the plurality of instances of downlink communications resources allocated for the transmission of data by the infrastructure equipment to the communications device via a wireless access interface, determining that uplink communication resources allocated for the transmission of a first portion of acknowledgement information are invalid and cannot be used for the transmission of the first portion of acknowledgement information, the first portion of acknowledgement information indicating an acknowledgement status of a respective instance of the downlink communication resources, in response to determining that the uplink communication resources allocated for the transmission of the first portion of acknowledgement information are invalid, selecting second uplink communication resources, and transmitting the first portion of acknowledgement information using the selected second uplink communication resources.

Embodiments of the present technique can provide an efficient method for transmitting acknowledgement information (such as a HARQ-ACK) associated with an instance of a periodic downlink resource allocation, such as an instance of an SPS PDSCH.

In some embodiments, the selected second uplink communication resources comprise one or more instances, and in one of the one or more instances, multiple portions of acknowledgement are transmitted.

In some embodiments, no indication of the second uplink communication resources is received after the invalid uplink communication resources allocated for the transmission of the first portion of acknowledgement information.

Accordingly, embodiments can provide a method for transmitting acknowledgement information with a low latency and/or making efficient using of the communication resources of the wireless access interface.

Embodiments of the present technique can therefore provide methods and apparatus for selecting additional (second) communication resources for the transmission of dropped HARQ-ACKs, without requiring additional downlink signalling after the PUCCH which was allocated for the transmission of the dropped HARQ-ACK.

Embodiments of the present technique can provide for a determination of additional communication resources which can be used for the transmission of HARQ-ACK information when earlier communication resources cannot be used. This determination may be carried out both by the communications device and by the infrastructure equipment, while avoiding further downlink control signalling after the original communication resources and prior to the additional communication resources.

In some embodiments, there may be one or more of the following procedures: triggering the selection of additional communication resources; selecting the additional communication resources; selecting HARQ-ACKs for transmission using the additional resources; and transmitting the selected HARQ-ACKs using the additional resources.

In the present disclosure, ‘invalid’ is used to refer to communication resources (such as an ‘invalid PUCCH’) which cannot be used for the transmission of any control information, due to, for example, a collision or overlap with communication resources which are designated as invalid or for downlink transmission. Conversely, valid communication resources (such as a ‘valid PUCCH’) refers to resources that can be used for the transmission of one or more HARQ-ACKs. Accordingly, for example, a valid PUCCH does not collide with, or overlap communication resources which are designated as invalid or for downlink transmission.

The term ‘outstanding HARQ-ACK’ is used to refer to a HARQ-ACK which has not yet been transmitted. A HARQ-ACK may be outstanding because resources which were allocated for its initial transmission were in fact invalid. For example, referring to Figure 7, PUCCH resources 908 were initially allocated for the transmission of a HARQ-ACK associated with the SPS PDSCH instance 904. However, because the PUCCH resources 908 are invalid, the HARQ-ACK associated with the SPS PDSCH instance 904 is not transmitted and is thus an ‘outstanding’ HARQ-ACK.

Triggering selection of additional communication resources

The communications device may determine that uplink communication resources allocated for the transmission of acknowledgement information associated with an instance of communication resources allocated by means of semi-persistent scheduling (SPS) are invalid. Such an instance is referred to herein as an invalid PUCCH. It will be appreciated however that the scope of the present disclosure is not limited to the case where the uplink communication resources are on PUCCH.

The acknowledgement information which would have been transmitted using the invalid PUCCH if it were in fact not invalid is referred herein to as the associated, or dropped, HARQ-ACK(s). As discussed above, the present disclosure is not limited to acknowledgement information generated pursuant to a HARQ scheme. A single invalid PUCCH may be associated with more than one HARQ-ACK if, for example, the transmission of acknowledgement information associated with multiple SPS instances is to occur within a single slot or sub-slot.

In some embodiments, additional communication resources are selected in response to an identification of an invalid PUCCH.

In some embodiments, additional communication resources are selected only if one or more invalid PUCCH instances meet certain predetermined criteria.

In some embodiments, additional communication resources are selected if a number of associated HARQ- ACKs which are associated with the invalid PUCCH instance(s) is equal to or exceeds a predetermined HARQ-ACK threshold.

The predetermined HARQ-ACK threshold may be specified in appropriate standards specifications.

The predetermined HARQ-ACK threshold may be indicated in radio resource control (RRC) configuration signalling transmitted by the infrastructure equipment to the communications device.

The predetermined HARQ-ACK threshold may be indicated in a downlink control information (DCI) transmission transmitted by the infrastructure equipment to the communications device. The DCI may be the same as that used to activate an SPS allocation.

The invalid PUCCH instances may be associated with different SPS allocations (e.g. with different SPS PDSCHs).

The communications device may maintain one or more counters of the number of associated HARQ- ACKs which are associated with the invalid PUCCH instance(s). When the value of this counter is equal to the predetermined HARQ-ACK threshold, the communications device may select the additional communication resources, and reset the counter. The counter may be reset to zero under certain conditions. In some embodiments, the counter is reset when all of the associated HARQ-ACKs which are associated with the invalid PUCCH instance(s) have been retransmitted.

In some embodiments, a timer of predetermined duration is started for each invalid PUCCH instance (e.g. starting at the end of the PUCCH instance). The counter is reset when no timer is running for any invalid PUCCH instance. Accordingly, additional communication resources are not selected if it is too late to retransmit any dropped HARQ-ACKs. In some embodiments, the only HARQ-ACKs which are considered when comparing against the predetermined HARQ-ACK threshold are those associated with an invalid PUCCH instance whose corresponding timer is still running.

Figure 8 illustrates additional communication resources selected in response to an identification of an invalid PUCCH in accordance with embodiments of the present technique.

In the example of Figure 8, an instance 1002 of a first SPS PDSCH occurs in slot n, and is associated with a KI value of 1. An instance 1004 of a second SPS PDSCH occurs in slot n+1 and is associated with a KI value of 0.

In accordance with the respective KI values, the HARQ-ACK for each of the instances 1002, 1004 of SPS PDSCHs is to be transmitted within slot n+1. The PUCCH resources 1006 for the transmission of the HARQ-ACKs extends from time t7 to time tlO.

However, the time t7 to time tlO includes a symbol period from time t7 to time t8 which is designated as a downlink symbol, and a symbol period from time t8 to time t9 which is designated as an invalid symbol. As described elsewhere herein, the designation of symbol periods as uplink, downlink or invalid may be indicated to the communications device by means of a slot format indicator (SFI) transmitted by the infrastructure equipment.

Accordingly, the communications device determines that the PUCCH resources 1006 are invalid.

In the example of Figure 8, the predetermined HARQ-ACK threshold is equal to two. Because the number of associated HARQ-ACKs which are associated with invalid PUCCH instance 1006 (two) is equal to or exceeds the predetermined HARQ-ACK threshold, then the communications device selects additional communication resources 1008 which occur from time tl5 to time tl 6.

From time tl 5 to time tl 6, all of the symbol periods are designated as uplink symbols. Accordingly, the communications device transmits the dropped HARQ-ACKs using the selected additional communication resources 1008. The dropped HARQ-ACKs are those indicating the acknowledgement status of data transmitted using the instances 1002, 1004 of the SPS PDSCHs.

Accordingly, embodiments of the present technique can provide for the transmission of dropped HARQ- ACKs without any additional signalling between the communications device and the infrastructure equipment.

The infrastructure equipment may perform a corresponding determination in respect of the PUCCH instance 1006, and may accordingly receive the dropped HARQ-ACKs which are transmitted using the additional communication resources.

The selection of the communication resources 1006 is described in further detail below. In some embodiments, the selection of the communication resources is in accordance with predetermined rules which are known both to the communications device and to the infrastructure equipment. In the example of Figure 8, both of the dropped HARQ-ACKs are considered when determining the number of HARQ-ACKs, for the purpose of determining whether to trigger the selection of additional communication resources.

In some embodiments, only a subset of HARQ-ACKs are counted.

For example, in some embodiments, HARQ-ACKs which are associated with certain SPS PDSCHs are not counted. In some embodiments, these SPS PDSCHs may be indicated by means of RRC signalling transmitted by the infrastructure equipment. In some embodiments, the communications device may determine whether a HARQ-ACKs is to be counted based on a logical channel associated with its associated SPS PDSCH. For example, a HARQ-ACK may be counted only if it is are associated with an SPS which is assigned a logical channel for providing URLLC service.

In some embodiments, each SPS PDSCH may be associated with a physical layer priority. For example, each SPS PDSCH may be associated with either a high physical layer priority or a low physical layer priority. In some such embodiments, the communications device may determine whether a HARQ-ACK is to be counted based on the physical layer priority of its associated SPS PDSCH. For example, a HARQ ACK may be counted only if the associated SPS PDSCH has the high physical layer priority.

Additionally or alternatively, in some embodiments, a DCI which indicates an activation or deactivation of an SPS may indicate whether HARQ-ACKs associated with instances of that SPS are to be counted when determined whether additional communication resources are to be selected.

In some embodiments, the evaluation is performed in respect of a slot or sub-slot in which the invalid PUCCH occurs. That is, a HARQ-ACK is counted, for the purpose of determining whether additional communication resources are to be selected, only if it would have been transmitted during the slot or subslot in which the invalid PUCCH occurs. In an example, the predetermined HARQ-ACK threshold is three. If a first invalid PUCCH occurs in timeslot n, and was for the transmission of two HARQ-ACKs, and a second invalid PUCCH occurs in time slot n+2, and was also for the transmission of two HARQ- ACKs, then the evaluation is carried out in respect of timeslots n and n+2 independently, and in neither case are additional communication resources selected.

Figure 9 illustrates additional communication resources selected in response to an identification of an invalid PUCCH in accordance with embodiments of the present technique.

In the example of Figure 9, an instance 1102 of a first SPS PDSCH occurs in slot n, and is associated with a KI value of 1. An instance 1104 of a second SPS PDSCH occurs in slot n+1 and is associated with a KI value of 1. An instance 1106 of a third SPS PDSCH occurs in slot n+3 and is associated with a KI value of 0. In the example of Figure 9, HARQ-ACKs associated with the first SPS PDSCH are not in the subset of HARQ-ACKs which are counted for the purpose of determining whether additional communication resources are selected. The predetermined HARQ-ACK threshold is one.

Respective first, second and third PUCCH resources 1112, 1114, 1116 are allocated for the transmission of HARQ-ACKs associated with the instances 1102, 1104, 1106 of the first to third SPS PDSCHs. However, the first and third PUCCH resources 1112, 1116 are invalid as they both overlap one or more symbol periods designated as downlink or invalid.

In response to determining that the first PUCCH resources 1112 are invalid, the communications device determines that the number of dropped HARQ-ACKs, for the purpose of determining whether to select additional communication resources, is zero. This is because the first PUCCH resources 1112 are for the transmission of a HARQ-ACK associated with the first SPS PDSCH, and thus the associated HARQ- ACK is not counted.

In contrast, in response to determining that the third PUCCH resources 1116 are invalid, the communications device determines that the number of dropped HARQ-ACKs, for the purpose of determining whether to select additional communication resources, is one. This is because the third PUCCH resources 1116 are for the transmission of a HARQ-ACK associated with the third SPS PDSCH, and thus the associated HARQ-ACK is counted. Because the determined number of dropped HARQ- ACKs (one) is greater than or equal to the predetermined HARQ-ACK threshold (one), additional communication resources 1120 are selected.

The communications device selects one or more HARQ-ACKs for transmission using the additional communication resources, and from time tl 9 until time t20, transmits the selected HARQ-ACKs using the additional communication resources 1120.

The selection of the HARQ-ACKs for transmission using the additional communication resources is described in further detail below.

In some embodiments, additional communication resources are selected if a number of invalid PUCCH instance(s) is equal to or exceeds a predetermined PUCCH threshold.

The predetermined PUCCH threshold may be specified in appropriate standards specifications.

The predetermined PUCCH threshold may be indicated in radio resource control (RRC) configuration signalling transmitted by the infrastructure equipment to the communications device.

The predetermined PUCCH threshold may be indicated in a downlink control information (DCI) transmission transmitted by the infrastructure equipment to the communications device. The DCI may be the same as that used to activate an SPS allocation.

The communications device may maintain one or more counters of the number of invalid PUCCH instance(s). When the value of this counter is equal to the predetermined PUCCH threshold, the communications device may select the additional communication resources, and reset the counter.

The counter may be reset to zero under certain conditions. In some embodiments, the counter is reset when all of the associated HARQ-ACKs which are associated with the invalid PUCCH instance(s) have been retransmitted.

Figure 10 illustrates additional communication resources selected in response to an identification of multiple invalid PUCCH instances in accordance with embodiments of the present technique.

In the example of Figure 10, an instance 1202 of a first SPS PDSCH occurs in slot n, and is associated with a KI value of 1. An instance 1204 of a second SPS PDSCH occurs in slot n+1 and is associated with a KI value of 1.

Respective first and second PUCCH resources 1212, 1214 are allocated for the transmission of HARQ- ACKs associated with the instances 1102, 1104 of the first and second SPS PDSCHs. However, the first and second PUCCH resources 1212, 1214 are invalid as they both overlap one or more symbol periods designated as downlink or invalid. In the example of Figure 10, the predetermined PUCCH threshold is two.

In accordance with embodiments of the present technique, the communications device determines that the first PUCCH instance 1212 is invalid, and calculates that the cumulative number of invalid PUCCH instances is one. Because this does not equal or exceed the predetermined PUCCH threshold, no additional communication resources are selected.

The communications device also determines that the second PUCCH instance 1214 is invalid, and in response calculates that the cumulative number of invalid PUCCH instances is two. Because this equals or exceeds the predetermined PUCCH threshold, additional communication resources 1220 are selected.

The additional communication resources 1220 are used to transmit one or more HARQ-ACKs that would otherwise have been transmitted using an invalid PUCCH.

The selection of the additional communication resources and the selection of the HARQ-ACKs is described in more detail elsewhere.

In some embodiments, all invalid PUCCH instances are counted when evaluating the number of invalid PUCCH instance(s), for the purpose of determining whether to select additional communication resources. In some embodiments, invalid PUCCH instances are not counted unless they satisfy certain predetermined criteria. The criteria may define a subset of PUCCH instances which are counted.

For example, the subset may correspond to PUCCH instances associated with a subset of SPS PDSCHs. The SPS PDSCHs within the subset of SPS PDSCHs may be configured by RRC signalling. An activation or deactivation DCI for an SPS PDSCH may indicate whether that SPS PDSCH is within the subset.

In some embodiments, the subset of SPS PDSCHs are those used for the transmission of traffic having certain quality of service requirements. For example, the subset of SPS PDSCHs may be those used for the transmission of URLUC traffic. The subset of SPS PDSCHs may include those associated with certain logical channels. The certain logical channels may be those used for the transmission of URLUC traffic.

In some embodiments, the subset of SPS PDSCHs are those with a certain physical layer priority. For example, the subset of SPS PDSCHs may be those with the high physical layer priority.

In the examples of Figure 8, Figure 9 and Figure 10, the selection of additional communication resources is triggered by an autonomous determination at the communications device. A corresponding determination may be carried out at the infrastructure equipment.

In some embodiments, the selection of additional communication resources by the communications device is in response to receiving a trigger indication from the infrastructure equipment that indicates that additional communication resources should be selected for the transmission of one or more HARQ- ACKs. The transmission of the trigger indication by the infrastructure equipment may be in response to any one of the criteria disclosed herein being satisfied, or for any other reason.

In some embodiments, the trigger indication is transmitted within a medium access control (MAC) control element (CE). In some embodiments, the MAC CE comprising the trigger indication is transmitted using an instance of downlink communication resources allocated as part of an SPS allocation. In some embodiments, if the communications device correctly decodes the MAC CE comprising the trigger indication, then it selects the additional communication resources and transmits a corresponding HARQ-ACK using the additional communication resources. The infrastructure equipment can accordingly determine that the communications device received and decoded the MAC CE (because it transmitted using the additional communication resources) and can determine whether or not the communications device correctly decoded the other data transmitted using the SPS resources, based on the HARQ-ACK.

If the communications device does not correctly decode the MAC CE, then it will not select the additional communication resources, and will not transmit using them. In response, the infrastructure equipment determines that the communications device did not receive and decode the MAC CE (because it did not transmit using the additional communication resources) and can determine that the communications device did not correctly decode the other data transmitted using the downlink SPS resources. This is because the MAC CE may be encoded more robustly than the other data and/or it may be necessary to decode the MAC CE in order to correctly decode the other data.

The infrastructure equipment may retransmit the data based on the determination as to whether the data transmitted using the SPS resources was received and decoded correctly. For example, where the infrastructure equipment determines that the communications device did not transmit using the additional communication resources, the infrastructure equipment may retransmit all of the data which was transmitted using the downlink SPS resources.

Selecting the additional communication resources

If the communications device determines that additional communication resources are to be selected, then these are selected in accordance with predetermined rules, such that the infrastructure equipment also determines the same additional communication resources.

In some embodiments, the additional communication resources can be determined by the communications device without reference to any signalling transmitted by the infrastructure equipment after the occurrence of the invalid PUCCH.

In some embodiments, the additional communication resources consist of a single instance of contiguous resources.

In some embodiments, the additional communication resources comprise a plurality of instances of resources.

In some embodiments, the additional communication resources are determined based on one or more additional resource indications transmitted by the infrastructure equipment. One or more additional resource indications may be transmitted in RRC signalling.

The additional communication resources may be PUCCH resources or physical uplink shared channel (PUSCH) resources.

In some embodiments, a MAC CE transmitted by the infrastructure equipment comprises an indication of the additional communication resources. The MAC CE may be transmitted using downlink resources of an instance of an SPS PDSCH. Where the additional communication resources are PUCCH resources, the indication of the additional communication resources may comprise a PUCCH resource indicator (PRI) which indicates resources within a slot or sub-slot, and a PDSCH-to-HARQ_feedback timing indicator, which indicates an offset (in slots or sub-slots) between the slot or sub-slot in which the MAC CE was transmitted, and the slot or sub-slot in which the additional communication resources occur. The PRI and PDSCH-to-HARQ_feedback timing indicator may be transmitted within the PDSCH in a manner similar to that used in a success random access response (SuccessRAR) in a conventional 2-step random access procedure.

If the additional communication resources are PUSCH resources, the MAC CE may comprise an uplink grant. The uplink grant may be transmitted in a manner similar to the transmission of an uplink grant which is transmitted within a random access response (RAR) message in a conventional 4-step random access procedure.

In some embodiments, the additional communication resources are determined based on a PUCCH instance, where the additional communication resources are selected in response to determining that that PUCCH instance is invalid. Where the additional communication resources are selected in response to determining that multiple PUCCH instances are invalid, the additional communication resources may be determined based on the latest of these.

For example, in some embodiments, the additional communication resources comprise the resources of the PUCCH instance, offset in time by a predetermined offset. The predetermined offset may be an integer number, KDROP, of slots or sub-slots.

In some embodiments, the value of KDROP is independent of the SPS PDSCH. That is, the value of KDROP is the same, irrespective of the SPS PDSCH associated with the PUCCH instance which was determined to be invalid. In some embodiments, a different value of KDROP may be associated with different SPS PDSCHs. Accordingly, in response to determining that additional communication resources are to be selected as a result of a PUCCH instance being determined to be invalid, the communications device may determine KDROP based on the SPS PDSCH associated with the PUCCH instance, and hence determine the additional communication resources.

The value(s) of KDROP may be indicated by the infrastructure equipment in dedicated signalling, such as RRC signalling or DCI signalling which activates or deactivates an SPS. The value(s) of KDROP may be specified in a standards specification.

Figure 11 illustrates additional communication resources selected in response to an identification of an invalid PUCCH in accordance with embodiments of the present technique.

In the example of Figure 11, an instance 1302 of a first SPS PDSCH occurs in slot n, and is associated with a KI value of 1, and a KDROP value of 1. An instance 1304 of a second SPS PDSCH occurs in slot n+1 and is associated with a KI value of 1 and a KDROP value of 2.

Respective first and second PUCCH resources 1312, 1314 are allocated for the transmission of HARQ- ACKs associated with the instances 1302, 1304 of the first and second SPS PDSCHs. However, the first and second PUCCH resources 1312, 1314 are invalid as they both overlap one or more symbol periods designated as downlink or invalid.

In the example of Figure 11, as a result of each of the dropped PUCCH instances 1312, 1314, the communications device determines that additional communication resources are to be selected. This determination may be in accordance with any of the techniques disclosed herein.

Based on the KDROP value (1) associated with the first SPS PDSCH, the communications device determines first additional communication resources 1322 as being one slot after the first PUCCH instance 1312. Similarly, based on the KDROP value (2) associated with the second SPS PDSCH, the communications device determines second additional communication resources 1324 as being two slots after the second PUCCH instance 1314.

In accordance with some embodiments, the communications device may determine that the additional communication resources are also invalid and may therefore refrain from transmitting using the additional communication resources.

In the example of Figure 11, the communications device determines that the first additional communication resources 1322 are invalid, as they comprise resources from time tl 1 to time 112, which is designated as an uplink symbol period. In response, the communications device refrains from transmitting using the first additional communication resources 1322.

In the example of Figure 11, the communications device determines that the second additional communication resources 1324 are not invalid. In response, the communications device transmits one or more HARQ-ACKs using the second additional communication resources 1322.

The one or more HARQ-ACKs may comprise the HARQ-ACK that would have been transmitted using the second PUCCH instance 1314, if the second PUCCH instance 1314 was not invalid.

In some embodiments, as described elsewhere herein, HARQ-ACKs may be multiplexed and transmitted using additional communication resources, even if they would not have been transmitted using the PUCCH instance which was determined to be invalid, where the determination that that PUCCH instance was invalid triggered the selection of the additional communication resources. For example, in the example of Figure 11, the second additional communication resources 1324 may additionally be used to transmit the HARQ-ACK which would have been transmitted using the first PUCCH instance 1312, if the first PUCCH instance 1312 was not invalid.

In some embodiments, one or more parameters for determining the additional communication resources may be indicated in RRC signalling transmitted by the infrastructure equipment. The parameters may comprise one or more of a duration of the additional communication resources, the KDROP value(s) associated with one or more SPS PDSCHs and a number of physical resource blocks which make up the additional communication resources.

Accordingly, embodiments of the present technique can provide for the selection of additional communication resources which differ in quantity or location (within a slot/sub-slot) from the PUCCH resources which were determined to be invalid.

In some embodiments, the additional communication resources are selected from a series of periodic resource instances. The infrastructure equipment may transmit an indication of these periodic resource instances, for example in a manner similar to the signalling for conventional SPS allocations of uplink resources.

In some embodiments, the periodic resource instances may be configured by means of RRC signalling transmitted by the infrastructure equipment. The RRC signalling may indicate the extent of each resource instance (e.g., time and frequency resources) and their periodicity. The RRC signalling may comprise a system frame number (SFN) offset for determining the start time of each instance.

Periodic resource instances may be configured independently for each SPS PDSCH. In some embodiments, a single series of periodic resource instances is configured for a plurality of SPS PDSCH, and in some embodiments, a single series of periodic resource instances is configured for all SPS PDSCH for a given communications device. The selected additional communication resources may be the next occurring instance of the series of periodic resource instances, after the invalid PUCCH.

Figure 12 illustrates additional communication resources selected in response to an identification of an invalid PUCCH in accordance with embodiments of the present technique.

In the example of Figure 12, an instance 1402 of a first SPS PDSCH occurs in slot n, and is associated with a KI value of 1. An instance 1404 of a second SPS PDSCH occurs in slot n+1 and is associated with a KI value of 1.

Respective first and second PUCCH resources 1412, 1414 are allocated for the transmission of HARQ- ACKs associated with the instances 1402, 1404 of the first and second SPS PDSCHs. However, the first and second PUCCH resources 1412, 1414 are invalid as they both overlap one or more symbol periods designated as downlink or invalid.

A series of periodic resource instances comprises first to third resource instances 1422, 1424, 1426 which may be selected as additional communication resources, and is applicable to all SPS PDSCHs configured for the communications device. It will be appreciated that the series may extend before and after the time period shown in Figure 12.

In the example of Figure 12, as a result of each of the dropped PUCCH instances 1412, 1414, the communications device determines that additional communication resources are to be selected. This determination may be in accordance with any of the techniques disclosed herein.

In response to determining that the first PUCCH instance 1412 in slot n+1 is invalid, the communications device selects the next instance of the series of periodic resources, which is the second instance 1424 of those shown in Figure 12, and occurs in slot n+2. However, the communications device determines that this resource instance is also invalid, as it overlaps a symbol period from time t7 to time t8, which is designated as an invalid symbol. In response, in accordance with some embodiments of the present technique, it selects the next instance of the series of periodic resources, which is the third instance 1426 of those shown in Figure 12, and occurs in slot n+4.

The communications device may determine that the third instance 1426 of the series is not invalid.

In response to determining that the second PUCCH instance 1414 in slot n+2 is invalid, the communications device selects the next instance of the series of periodic resources, which is the third instance 1426 of those shown in Figure 12, and occurs in slot n+4.

Accordingly, in the example of Figure 12, the communications device selects, as the additional communication resources, the same instance of the series of periodic resources for the transmission of two HARQ-ACKs. The two HARQ-ACKs are those associated with (i.e. indicating the acknowledgement status of) the instance 1402 of the first SPS PDSCH and the instance 1404 of the second SPS PDSCH.

From time tl 8 to time tl 9, the communications device transmits using the third instance of the series of periodic resources 1426 and transmits the two HARQ-ACKs.

The example of Figure 12 illustrates an embodiment in which iterative selection of additional communication resources may be carried out in response to determining that an instance of additional communication resources is itself invalid. However, the disclosure is not so limited and in other embodiments, no such iterative selection is carried out. In some embodiments, iterative selection is carried out in conjunction with other techniques disclosed herein. The example of Figure 12 also illustrates the multiplexing of multiple HARQ-ACKs would have been transmitted using different PUCCH instances, had those PUCCH instances not been invalid. However, the disclosure is not so limited and in other embodiments, no such multiplexing is carried out. In some embodiments, multiplexing is carried out in conjunction with other techniques disclosed herein.

In some embodiments, the additional communication resources additional to, and separate from, communication resources allocated for the transmission of acknowledgement information by the communications device. For example, referring to Figure 12, the instances 1422, 1424, 1426 of the series of periodic resources may not be allocated for the transmission of control information by the communications device other than in the specific circumstances where a PUCCH is determined to be invalid.

Accordingly, embodiments of the present technique can provide for a selection of additional communication resources which are not otherwise allocated for transmission by the communications device.

In some embodiments, the additional communication resources are uplink resources which are allocated to the communications device for the transmission of other control information or other HARQ-ACKs. The uplink resources may be allocated on a PUCCH, and may be allocated for the transmission of acknowledgement information associated with data transmitted using a PDSCH instance. The PDSCH instance may be an instance of an SPS PDSCH or may be allocated by a dynamic grant. The PDSCH may be different from the SPS PDSCH associated with the invalid PUCCH which triggered the selection of the additional communication resources.

In some embodiments, the additional communication resources may be selected in accordance with one or more techniques disclosed in co-pending application [8], the contents of which is incorporated herein by reference in its entirety.

In the examples of Figure 9, Figure 10, Figure 11 and Figure 12, the communications device selects a single instance of additional communication resources in response to determining that additional communication resources are to be selected, and only a single instance of additional resources is accordingly used for the transmission of one or more HARQ-ACKs.

In some embodiments, two or more instances of additional communication resources are selected and used for the transmission of one or more HARQ-ACKs.

For example, in some embodiments, the communications device may select a plurality of instances NSP of additional communication resources. These instances may be periodic.

In some embodiments, the number of instances NSP is predetermined. The predetermined number of instances NSP may be signalled by the infrastructure equipment in RRC signalling or in a DCI which may activate or deactivate an SPS PDSCH. In some embodiments, the predetermined number of instances NSP is specified in a suitable standards specification.

A periodicity of the instances may be signalled in RRC signalling or a DCI, or may be specified. In some embodiments, the periodicity is one slot (or one sub-slot, if the dropped PUCCH is allocated on a sub-slot basis).

Figure 13 illustrates additional communication resources selected in response to an identification of an invalid PUCCH in accordance with embodiments of the present technique, wherein the additional communication resources comprise a plurality of resource instances. In the example of Figure 13, an instance 1502 of a first SPS PDSCH occurs in slot n, and is associated with a KI value of 1. An instance 1504 of a second SPS PDSCH occurs in slot n+1 and is associated with a KI value of 1.

Respective first and second PUCCH resources 1512, 1514 are allocated for the transmission of HARQ- ACKs associated with the instances 1502, 1504 of the first and second SPS PDSCHs. The first PUCCH resources 1512 are valid, and the communications device transmits a HARQ-ACK indicating the acknowledgement status of the data received during the instance 1502 of the first SPS PDSCH.

However, the second PUCCH resources 1514 are invalid as they overlap one or more symbol periods designated as downlink or invalid. In the example of Figure 13, the criteria for selecting additional communication resources are satisfied, and the communications device selects additional communication resources.

In the example of Figure 13, the number of instances NSP is three, the periodicity is one slot, and the location of the resources within a slot and the offset of the first slot in which the resources occur are also predetermined.

Accordingly, the communications device selects the three instances 1522, 1524, 1526 shown in Figure 13 as the additional communication resources.

The communications device determines that the first instance 1522 is in fact invalid as it overlaps time period 115 to time 116 which is designated as an invalid symbol period. Accordingly, the communications device does not transmit using the first instance 1522.

In the example of Figure 13, the communications device transmits a HARQ-ACK for the downlink data received in the instance 1504 of the second SPS PDSCH using the second and third instances 1524, 1526 of the additional communication resources. These transmissions may use repetition encoding where the same information is encoded and transmitted using each of the second and third instances 1524, 1526.

In the example of Figure 13, each of the instances of the additional communication resources, which are not invalid, are used for the transmission of the HARQ-ACK(s). In some embodiments, fewer instances may be used, if it is possible to transmit all of the selected HARQ-ACKs using the fewer instances.

Figure 14 illustrates additional communication resources selected in response to an identification of an invalid PUCCH in accordance with embodiments of the present technique, wherein the additional communication resources comprise a plurality of resource instances and where one or more instances is not used if it is possible to transmit the selected HARQ-ACKs without using all valid instances.

The example of Figure 14 is similar to that shown in Figure 13. In particular, the number of instances NSP is three, the periodicity is one slot, and the location of the resources within a slot and the offset of the first slot in which the resources occur are also predetermined.

Accordingly, as in the example of Figure 13, the communications device selects three instances as the additional communication resources, of which only the first two 1522, 1524 are shown in Figure 14.

The communications device determines that the only HARQ-ACK to be transmitted using the additional communication resources is that indicating the acknowledgement status of the data transmitted using the instance 1504 of the second SPS PDSCH. This determination may be in accordance with techniques disclosed elsewhere herein.

The communications device further determines that the resources of one instance of the selected additional communication resources are sufficient to transmit the HARQ-ACK. This determination may be based on a selected coding and modulation scheme. The selected coding and modulation scheme may be that which would have been used to transmit the HARQ-ACK using the second PUCCH resources 1514, if they were valid.

The communications device transmits the HARQ-ACK using the earliest valid instances of the additional communication resources which are needed to transmit the HARQ-ACK.

In the example of Figure 14, the communications device accordingly transmits the HARQ-ACK using the second instance 1524 of the additional communication resources, and does not transmit using either the first or third instances.

In the examples of Figure 13 and Figure 14, the number of instances of the additional communication resources NSP is predetermined, although the communications device may in fact transmit using only a subset of these.

In some embodiments, the number of instances may be dynamically indicated by the infrastructure equipment. In some such embodiments, the number of instances is indicated by a termination indication transmitted by the infrastructure equipment. The termination indication indicates an end of a series of instances of additional communication resources. For example, the termination indication may be transmitted at a certain time TTERM, to indicate that no instances of additional communication resources occur after time TTERM.

Figure 15 illustrates additional communication resources selected in response to an identification of an invalid PUCCH in accordance with embodiments of the present technique, wherein the additional communication resources comprise a plurality of resource instances and where the number of such resource instances is indicated by the reception of a termination indication.

As in the example of Figure 13, an instance 1502 of a first SPS PDSCH occurs in slot n, and is associated with a KI value of 1. An instance 1504 of a second SPS PDSCH occurs in slot n+1 and is associated with a KI value of 1.

The second PUCCH resources 1514 are invalid as they overlap one or more symbol periods designated as downlink or invalid. As in the example of Figure 13, the criteria for selecting additional communication resources are satisfied, and the communications device selects additional communication resources.

As in the example of Figure 13, the additional communication resources comprise a plurality of resource instances. However, the number of resource instances is determined based on the reception of a termination indicator transmitted by the infrastructure equipment.

In the example of Figure 15, the termination indicator is transmitted in a DCI 1530 at time tl 9, and indicates that no further instances of the additional communication resources occur after the time (t20) at which the termination indicator is received.

In response to determining that the second PUCCH resources 1514 are invalid, the communications device selects the additional communication resources comprising at least the first instance 1522. Because no termination indicator has been received, the number of instances of additional communication resources is initially unknown. The first instance 1522 is valid, and accordingly the communications device transmits the HARQ-ACK using the first instance 1522. Because no termination indicator is received before the second instance 1524, the communications device may also transmit the HARQ-ACK using the second instance 1524.

From time tl 9 to time t20, the communications device receives the DCI 1530 comprising the termination indicator. In response, the communications device determines that no further instances of the additional communication resources occur after time t20 and refrains from any further transmission of the HARQ- ACK.

Because the termination indication can be sent after the additional communication resources which are used to transmit the HARQ-ACK(s), the latency of the HARQ-ACK transmissions does not depend on the exact timing of the transmission of the termination indication. Accordingly, embodiments of the present technique can minimise delays in transmitting the HARQ-ACKs. Because the number of resource instances is dynamically indicated, the infrastructure equipment can dynamically allocate an appropriate number of resource instances in each case where additional communication resources are selected.

In some embodiments, two or more of the techniques described above and illustrated in Figure 11, Figure 12, Figure 13, Figure 14, or Figure 15 may be combined. Accordingly, the communications device may determine multiple additional communication resources. In some embodiments, the HARQ-ACKs selected for transmission may be transmitted using only the earliest-occurring of these.

Transmitting HARQ-ACKs using the additional communications resources

In accordance with embodiments of the present technique, additional communication resources are selected and some or all of these are used for the transmission of one or more HARQ-ACKs.

In some embodiments of the present technique, the communications device selects the one or more HARQ-ACKs which are to be transmitted using the additional communication resources.

In some embodiments, all dropped acknowledgement information (such as HARQ-ACKs) which are associated with data transmitted using SPS PDSCH resources are selected for transmission. An example of this is shown in Figure 11, in which dropped HARQ-ACKs associated with the instances 1302, 1304 of both the first SPS PDSCH and the second SPS PDSCH, even though it was the invalid PUCCH 1314 which triggered the selection of the additional communication resources 1324.

In some embodiments, a subset of dropped HARQ-ACKs which are associated with data transmitted using SPS PDSCH resources are selected for transmission. The subset may be configured by the infrastructure equipment and indicated to the communications device in RRC signalling. In some embodiments, a MAC CE may comprise an indication of which HARQ-ACKs are to be selected. For example, the MAC CE may comprise a bitmap comprising a plurality of bits, each bit corresponding to a different HARQ process. If a bit is set to a first value (e.g. 1) then dropped HARQ-ACKs associated with the corresponding HARQ process are within the subset. Dropped HARQ-ACKs associated with a HARQ process whose corresponding bit is set to a second value (e.g. 0) are not within the subset.

The infrastructure equipment may additionally or alternatively indicate, in a DCI which activates or deactivates an SPS PDSCH, whether HARQ-ACKs associated with data transmitted using resources of that SPS PDSCH are to be included in the subset.

In some embodiments, HARQ-ACKs are selected for transmission in accordance with one or more of the techniques disclosed in co-pending application [8] . In some embodiments, the communications device is configured with multiple HARQ processes. In some such embodiments a HARQ-ACK associated with each configured HARQ process is selected for transmission.

In some embodiments, a HARQ-ACK associated with each SPS PDSCH is selected for transmission.

In some embodiments, the communications device determined, for each SPS PDSCH, whether that SPS PDSCH meets certain predetermined criteria. If it does, then a HARQ-ACK associated with that SPS PDSCH is selected for transmission. In some embodiments, the predetermined criteria may be those described above for determining, based on its associated SPS PDSCH, whether an invalid PUCCH is considered when determining whether to select the additional communication resources.

Where two or more HARQ-ACKs are selected for transmission, the two or more HARQ-ACKs may be encoded using a suitable codebook. An example of a suitable codebook is a Type 3 HARQ-ACK codebook, which is already specified for the transmission of multiple HARQ-ACKs using a single instance of communication resources. In accordance with conventional techniques, when using a Type 3 HARQ-ACK codebook, the HARQ-ACK for all configured HARQ processes are transmitted regardless of whether any of these HARQ-ACKs are previously dropped or not.

However, in accordance with embodiments of the present technique, no additional DCI is transmitted prior to the additional communication resources to indicate the allocation of the additional communication resources which may be used to transmit the multiple HARQ-ACKs which are encoded using the Type 3 HARQ-ACK codebook.

Embodiments of the present technique can therefore reduce an amount of downlink control channel resources required.

The process starts at step SI 902 in which the communications device receives an indication of an SPS configuration, defining an SPS PDSCH. The SPS configuration may specify the resources of instances of the SPS PDSCH, and PUCCH resources to be used for transmitting HARQ-ACK information associated with data transmitted using the SPS PDSCH instances.

The SPS configuration may be conventional SPS configuration signalling, such as using RRC configuration signalling.

In some embodiments, in a subsequent step (not shown in Figure 16) the communications device may receive an activation indication to indicate that an SPS PDSCH is activated. While the SPS PDSCH is activated, the communications device monitors the instances of SPS PDSCH and attempts to decode data which may be transmitted by the infrastructure equipment using those resources. In some embodiments, the infrastructure equipment may refrain from transmitting any data to the communications device using an instance of an activated SPS PDSCH because, for example, there is no data associated with the SPS PDSCH which is buffered at the infrastructure equipment for transmission.

The process continues at step SI 904, in which the communications device determines an acknowledgement status of data transmitted using an instance of an SPS PDSCH. The communications device may determine that no data was transmitted using the instance, that data was transmitted but not received and decoded correctly, or that data was transmitted and received and decoded correctly. In some embodiments, if the communications device determines that no data was transmitted using the instance, then the process ends in respect of that instance. The process may continue with step SI 904 in respect of a further instance of the same or a different SPS PDSCH. Otherwise, the process continues with step SI 906.

In some embodiments, if the communications device determines that no data was transmitted using the instance, then the process continues with step SI 906 and the corresponding HARQ-ACK indicates a negative acknowledgement (NACK) forthat instance.

At step SI 906, the communications device determines that the PUCCH resources allocated for transmitting the HARQ-ACK comprising the acknowledgement information determined at step SI 904 is invalid. For example, this may be because the wireless access interface is a TDD interface and the PUCCH resources overlap resources which are designated for downlink transmission or are designated as invalid (i.e. during which no transmission occurs). Accordingly, the HARQ-ACK comprising the acknowledgement information determined at step SI 904 may be determined to be a ‘dropped HARQ- ACK’.

Subsequently, at step SI 908, the communications device determines whether the PUCCH instance meets certain predetermined criteria. If it does not, the control returns to step S 1904 in respect of a further SPS PDSCH instance. As described elsewhere herein, the predetermined criteria may be based on the SPS PDSCH associated with the PUCCH instance.

If at step SI 908, the communications device determines that the PUCCH instance meets the predetermined criteria, the control passes to step S 1910. At step S 1910, the communications device determines whether trigger criteria for selecting additional communication resources are satisfied. As described elsewhere, this may be based on a cumulative number of dropped HARQ-ACKs, or a cumulative number of invalid PUCCH instances.

If the trigger criteria are not satisfied, then control returns to step SI 904 in respect of a further SPS PDSCH instance.

If the trigger criteria are satisfied, then control passes to step S 1912. At step S 1912, additional communication resources are selected. In some embodiments, this may comprise a plurality of instances of additional communication resources. In some embodiments, the number of instances of additional communication resources may not be known at step S 1912 and a first instance is selected.

Control then passes to step S 1914 in which the communications device selects one or more HARQ-ACKs for transmission using the additional communication resources. The one or more HARQ-ACKs may comprise the dropped HARQ-ACK comprising the acknowledgement information determined at step SI 904. The one or more HARQ-ACKs may comprise one or more other dropped HARQ-ACKs and/or one or more other HARQ-ACKs which have previously been transmitted.

Control then passes to step S 1916. At step S 1916, the communications device determines whether the first (or only) instance of selected additional communication resources is invalid. The instance of selected additional communication resources may be invalid because it overlaps downlink and/or invalid time periods of a TDD wireless access interface.

If the instance of selected additional communication resources is invalid (‘Yes’) then control passes to step S1922. Otherwise (‘No’), control passes to step S 1918.

At step S 1918, the communications device encodes the selected HARQ-ACK(s) and transmits these using the instance of additional communication resources. In some embodiments, multiple HARQ-ACKs may be encoded using a Type 3 HARQ-ACK codebook, and transmited using a single instance of the additional communication resources.

In some embodiments, the HARQ-ACKs transmited at step S 1918 may have been transmited in an earlier instance of the additional communication resources, at a previous iteration of step S 1918.

Control then passes to step SI 920. In step SI 920, the communications device determines whether there are HARQ-ACKs which were identified at step S 1914 and which have not yet been transmited. If so (‘Yes’), then control passes to step S1922. Otherwise (‘No’), control passes to step S1924 and the process ends.

At step SI 922, the communications device determines whether there are instances of the additional communication resources which have not been used. This may comprise determining whether a predetermined number NSP of instances has been reached, and/or whether a termination indicator has been received.

If there remains one or more instances of the additional communication resources which have not been used (‘Yes’), the control passes to step S1926 and a next instance of the additional communication resources is selected. The process then returns to step S 1916 and the process continues for the selected next instance of the additional communication resources.

If, at step SI 922, it is determined that there are no more instances of the additional communication resources which have not been used, then control passes to step S1924 and the process ends.

In some embodiments, at step SI 924, the process may continue with step SI 904 in respect of a further instance of an SPS PDSCH.

Above have been given descriptions of an example process. The scope of the present disclosure is not, however, limited to the specific combination and order of steps and in some embodiments, one or more of the steps described may be omited, or combined in a different order, or modified. Features or steps described in the context of one example may be combined with features or steps described in the context of another example.

For example, in some embodiments, the number of instances of additional communication resources is one, and accordingly steps SI 920, SI 922 and SI 926 may be omited, with control passing from step S 1918 to step S1924 (or to step SI 906). In some embodiments, there may be no criteria applicable for PUCCH instances, and step S1908 may be omited, with control passing directly from step SI 906 to step S1910.

Techniques and principles disclosed above in the context of one example may be combined with techniques and principles disclosed in the context of one or more other examples.

Embodiments of the present technique also provide a method for operating an infrastructure equipment of a wireless communications network. In some such embodiments, the infrastructure equipment may transmit parameters for allowing a communications device to select additional communication resources in response to determining that criteria for selecting the additional communication resources have been satisfied. In some embodiments, the communications device is accordingly able to select at least an initial instance of the additional communication resources without receiving any allocation signalling relating to the additional communication resources after the communications device determines that the criteria have been satisfied. In some embodiments, the infrastructure equipment may transmit parameters for allowing a communications device to determine whether criteria for selecting the additional communication resources have been satisfied.

In some embodiments, the infrastructure equipment may transmit a termination indicator for allowing a communications device to determine whether further instances of the additional communication resources are available.

In some embodiments, the infrastructure equipment may carry out one or more determinations described herein for determining that the criteria for selecting additional communication resources have been satisfied and/or for selecting the additional communication resources. Having determined that trigger criteria have been met, and selected the additional communication resources in a manner consistent with that used by the communications device, the infrastructure equipment may receive and decode the one or more HARQ-ACKs which are transmitted by the communications device using the additional communication resources.

Thus there has been described a method of transmitting control information by a communications device in a wireless communications network, the method comprising receiving from an infrastructure equipment of the wireless communications network an indication of a plurality of instances of downlink communications resources associated with a semi-persistent resource allocation, the plurality of instances of downlink communications resources allocated for the transmission of data by the infrastructure equipment to the communications device via a wireless access interface, determining that uplink communication resources allocated for the transmission of a first portion of acknowledgement information is invalid and cannot be used for the transmission of the first portion of acknowledgement information, the first portion of acknowledgement information indicating an acknowledgement status of a respective instance of the downlink communication resources, in response to determining that the uplink communication resources allocated for the transmission of the first portion of acknowledgement information are invalid, selecting second uplink communication resources, and transmitting the first portion of acknowledgement information using the selected second uplink communication resources.

There has also been described a method of receiving at an infrastructure equipment control information transmitted by a communications device in a wireless communications network, the method comprising transmitting an indication of a plurality of instances of downlink communications resources associated with a semi-persistent resource allocation, the plurality of instances of downlink communications resources allocated for the transmission of data by the infrastructure equipment to the communications device via a wireless access interface, determining that uplink communication resources allocated for the transmission of a first portion of acknowledgement information are invalid and cannot be used for the transmission of the first portion of acknowledgement information, the first portion of acknowledgement information indicating an acknowledgement status of a respective instance of the downlink communication resources, in response to determining that the uplink communication resources allocated for the transmission of the first portion of acknowledgement information are invalid, selecting second uplink communication resources, and receiving the first portion of acknowledgement information transmitted using the selected second uplink communication resources..

Corresponding apparatus, circuitry and computer readable media have also been described.

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.

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 transmitting control information by a communications device in a wireless communications network, the method comprising receiving from an infrastructure equipment of the wireless communications network an indication of a plurality of instances of downlink communications resources associated with a semi-persistent resource allocation, the plurality of instances of downlink communications resources allocated for the transmission of data by the infrastructure equipment to the communications device via a wireless access interface, determining that uplink communication resources allocated for the transmission of a first portion of acknowledgement information is invalid and cannot be used for the transmission of the first portion of acknowledgement information, the first portion of acknowledgement information indicating an acknowledgement status of a respective instance of the downlink communication resources, in response to determining that the uplink communication resources allocated for the transmission of the first portion of acknowledgement information are invalid, selecting second uplink communication resources, and transmitting the first portion of acknowledgement information using the selected second uplink communication resources.

Paragraph 2. A method according to paragraph 1, the method comprising determining that one or more instances of uplink communication resources allocated for the transmission of portions of acknowledgement information including the first portion of acknowledgment information are invalid and cannot be used for the transmission of the acknowledgement information.

Paragraph 3. A method according to paragraph 2, wherein selecting the second uplink communication resources is in response to determining that the number of the instances of uplink communication resources allocated for the transmission of portions of acknowledgement information which are invalid exceeds a first predetermined threshold.

Paragraph 4. A method according to paragraph 2 or paragraph 3, the method comprising determining a number of portions of acknowledgement information for which the one or more instances of uplink communication resources were allocated, and determining that the number of portions of acknowledgement information exceeds a second predetermined threshold, wherein selecting the second uplink communication resources is in response to determining that the number of portions of acknowledgement information exceeds the second predetermined threshold.

Paragraph 5. A method according to any of paragraphs 2 to 4, the method comprising determining that the one or more instances of uplink communication resources meet predetermined criteria.

Paragraph 6. A method according to paragraph 5, wherein an instance of uplink communication resources meets the predetermined criteria if the instance of uplink communication resources was allocated for the transmission of acknowledgement information associated with downlink data, and the downlink data meets second predetermined criteria.

Paragraph 7. A method according to paragraph 6, wherein downlink data meets the second predetermined criteria if it is associated with a first logical channel.

Paragraph 8. A method according to paragraph 6 or paragraph 7, wherein downlink data meets the second predetermined criteria if it is associated with a first physical layer priority.

Paragraph 9. A method according to paragraph 7 or paragraph 8, the method comprising receiving an indication of the second predetermined criteria, the indication transmitted by the infrastructure equipment using radio resource control (RRC) signalling.

Paragraph 10. A method according to any of paragraphs 1 to 9, the method comprising receiving a trigger indication, the trigger indication transmitted using an instance of the downlink communications resources associated with a semi-persistent resource allocation, wherein selecting the second uplink communication resources is in response to receiving the trigger indication.

Paragraph 11. A method according to paragraph 10, wherein the trigger indication is indicated in a medium access control (MAC) control element (CE) transmitted by the infrastructure equipment using the instance of the downlink communication resources.

Paragraph 12. A method according to any of paragraphs 1 to 11, wherein no indication of the second uplink communication resources is received after the respective instance of the downlink communication resources.

Paragraph 13. A method according to any of paragraphs 1 to 12, wherein the second uplink communication resources are on a physical uplink shared channel.

Paragraph 14. A method according to any of paragraphs 1 to 12, wherein the second uplink communication resources are on a physical uplink control channel.

Paragraph 15. A method according to any of paragraphs 1 to 14, wherein the selecting the second uplink communication resources is based on one or more first parameters indicated in radio resource control (RRC) signalling transmitted by the infrastructure equipment before the respective instance of the downlink communication resources.

Paragraph 16. A method according to any of paragraphs 1 to 15, wherein the selecting the second uplink communication resources is based on one or more second parameters indicated in signalling transmitted by the infrastructure equipment using the respective instance of the downlink communication resources. Paragraph 17. A method according to paragraph 16, wherein the second parameters are indicated in a medium access control (MAC) control element (CE) transmitted by the infrastructure equipment using the respective instance of the downlink communication resources.

Paragraph 18. A method according to any of paragraphs 1 to 17, wherein the selecting the second uplink communication resources is based on the uplink communication resources allocated for the transmission of the first portion of acknowledgement information.

Paragraph 19. A method according to any of paragraphs 1 to 18, wherein the selecting the second uplink communication resources is based on a predetermined number of slots or sub-slots between a slot or subslot containing the uplink communication resources allocated for the transmission of the first portion of acknowledgement information and a slot or sub-slot containing the second uplink communication resources.

Paragraph 20. A method according to paragraph 19, wherein the predetermined number of slots or subslots is common to a plurality of semi-persistent resource allocations.

Paragraph 21. A method according to paragraph 19 or paragraph 20, the method comprising receiving an indication of the predetermined number of slots or sub-slots.

Paragraph 22. A method according to paragraph 21, wherein the indication of the predetermined number of slots or sub-slots is transmitted by the infrastructure equipment in RRC signalling.

Paragraph 23. A method according to paragraph 21, wherein the indication of the predetermined number of slots or sub-slots is transmitted by the infrastructure in a downlink control information (DCI) Paragraph 24. A method according to any of paragraphs 1 to 23, wherein the second uplink communication resources is selected from a plurality of periodic resource instances.

Paragraph 25. A method according to any of paragraphs 1 to 24, wherein the second uplink communication resources consist of a plurality of instances of uplink communication resources. Paragraph 26. A method according to paragraph 25, wherein the number of instances in the plurality of instances of uplink communication resources is predetermined.

Paragraph 27. A method according to paragraph 25, the method comprising receiving a termination indicator transmitted by the infrastructure equipment at a time, the termination indicator indicating that none of the plurality of instances of uplink communication resources occurs after the time.

Paragraph 28. A method according to any of paragraphs 25 to 27, the method comprising determining that one of the plurality of instances of uplink communication resources is invalid and in response to determining that one of the plurality of instances of uplink communication resources is invalid, refraining from transmitting acknowledgement information using the one of the plurality of instances of uplink communication resources which is invalid.

Paragraph 29. A method according to any of paragraphs 1 to 28, the method comprising selecting one or more portions of acknowledgement information including the first portion of acknowledgement information for transmission using the second uplink communication resources.

Paragraph 30. A method according to paragraph 29, the method comprising determining a number of the plurality of instances of uplink communication resources required to transmit the selected one or more portions of acknowledgement information, wherein the transmitting the first portion of acknowledgement information using the second uplink communication resources is by transmitting the selected portions of acknowledgement information using the determined number of the plurality of instances of uplink communication resources.

Paragraph 31. A method according to paragraph 29, the method comprising encoding the one or more portions of acknowledgement information in accordance with a codebook for transmitting multiple portions of acknowledgement information using a single instance of communication resources, wherein transmitting the first portion of acknowledgement information using the second uplink communication resources is by transmitting the encoded the one or more portions of acknowledgement information. Paragraph 32. A method according to any of paragraphs 29 to 31, wherein the selecting the one or more portions of acknowledgement information comprises selecting acknowledgement information for each of a plurality of configured hybrid automatic repeat request (HARQ) processes.

Paragraph 33. A method according to any of paragraphs 29 to 31, wherein the selecting the one or more portions of acknowledgement information comprises selecting acknowledgement information associated with a plurality of semi-persistent resource allocations, including the semi-persistent resource allocation. Paragraph 34. A method according to any of paragraphs 29 to 31, wherein the selecting the one or more portions of acknowledgement information comprises selecting acknowledgement information associated with one or more semi-persistent resource allocations allocated for the transmission of data which meets the second predetermined criteria, including the semi-persistent resource allocation.

Paragraph 35. A method according to any of paragraphs 29 to 31, wherein the selecting the one or more portions of acknowledgement information comprises selecting acknowledgement information associated with one or more semi-persistent resource allocations which meet third predetermined criteria, including the semi-persistent resource allocation.

Paragraph 36. A method according to any of paragraphs 29 to 35, wherein the selecting the one or more portions of acknowledgement information comprises selecting only dropped acknowledgement information.

Paragraph 37. A method according to any of paragraphs 1 to 36, the method comprising receiving a MAC CE comprising an indication, for each of one or more semi-persistent resource allocations, of whether acknowledgement information associated with the semi-persistent resource allocation may be selected for transmission using the second uplink communication resources.

Paragraph 38. A method of receiving at an infrastructure equipment control information transmittted by a communications device in a wireless communications network, the method comprising transmitting an indication of a plurality of instances of downlink communications resources associated with a semi- persistent resource allocation, the plurality of instances of downlink communications resources allocated for the transmission of data by the infrastructure equipment to the communications device via a wireless access interface, determining that uplink communication resources allocated for the transmission of a first portion of acknowledgement information are invalid and cannot be used for the transmission of the first portion of acknowledgement information, the first portion of acknowledgement information indicating an acknowledgement status of a respective instance of the downlink communication resources, in response to determining that the uplink communication resources allocated for the transmission of the first portion of acknowledgement information are invalid, selecting second uplink communication resources, and receiving the first portion of acknowledgement information transmitted using the selected second uplink communication resources.

Paragraph 39. A communications device for operating in a wireless communications network, the communications device comprising a transmitter configured to transmit signals on a wireless access interface provided by an infrastructure equipment of the wireless communications network, a receiver configured to receive signals on the wireless access interface, and a controller configured to control the transmitter and the receiver so that the communications device is operable to receive from the infrastructure equipment an indication of a plurality of instances of downlink communications resources associated with a semi-persistent resource allocation, the plurality of instances of downlink communications resources allocated for the transmission of data by the infrastructure equipment to the communications device via a wireless access interface, to determine that uplink communication resources allocated for the transmission of a first portion of acknowledgement information is invalid and cannot be used for the transmission of the first portion of acknowledgement information, the first portion of acknowledgement information indicating an acknowledgement status of a respective instance of the downlink communication resources, in response to determining that the uplink communication resources allocated for the transmission of the first portion of acknowledgement information are invalid, to select second uplink communication resources, and to transmit the first portion of acknowledgement information using the selected second uplink communication resources.

Paragraph 40. Circuitry for a communications device for operating in a wireless communications network, the circuitry comprising transmitter circuitry configured to transmit signals on a wireless access interface provided by an infrastructure equipment of the wireless communications network, receiver circuitry configured to receive signals on the wireless access interface, and controller circuitry configured to control the transmitter circuitry and the receiver circuitry so that the communications device is operable to receive from the infrastructure equipment an indication of a plurality of instances of downlink communications resources associated with a semi-persistent resource allocation, the plurality of instances of downlink communications resources allocated for the transmission of data by the infrastructure equipment to the communications device via a wireless access interface, to determine that uplink communication resources allocated for the transmission of a first portion of acknowledgement information is invalid and cannot be used for the transmission of the first portion of acknowledgement information, the first portion of acknowledgement information indicating an acknowledgement status of a respective instance of the downlink communication resources, in response to determining that the uplink communication resources allocated for the transmission of the first portion of acknowledgement information are invalid, to select second uplink communication resources, and to transmit the first portion of acknowledgement information using the selected second uplink communication resources.

Paragraph 41. Infrastructure equipment for use in a wireless communications network, the infrastructure equipment providing a wireless access interface, the infrastructure equipment comprising a transmitter configured to transmit signals via the wireless access interface, a receiver configured to receive signals, and a controller configured to control the transmitter and the receiver so that the infrastructure equipment is operable to transmit to a communications device an indication of a plurality of instances of downlink communications resources associated with a semi-persistent resource allocation, the plurality of instances of downlink communications resources allocated for the transmission of data by the infrastructure equipment to the communications device via the wireless access interface, to determine that uplink communication resources allocated for the transmission of a first portion of acknowledgement information are invalid and cannot be used for the transmission of the first portion of acknowledgement information, the first portion of acknowledgement information indicating an acknowledgement status of a respective instance of the downlink communication resources, in response to determining that the uplink communication resources allocated for the transmission of the first portion of acknowledgement information are invalid, to select second uplink communication resources, and to receive the first portion of acknowledgement information transmitted using the selected second uplink communication resources. Paragraph 42. Circuitry for infrastructure equipment for use in a wireless communications network, the infrastructure equipment providing a wireless access interface, the circuitry comprising transmitter circuitry configured to transmit signals via the wireless access interface, receiver circuitry configured to receive signals, and controller circuitry configured to control the transmitter circuitry and the receiver circuitry so that the infrastructure equipment is operable to transmit to a communications device an indication of a plurality of instances of downlink communications resources associated with a semi- persistent resource allocation, the plurality of instances of downlink communications resources allocated for the transmission of data by the infrastructure equipment to the communications device via the wireless access interface, to determine that uplink communication resources allocated for the transmission of a first portion of acknowledgement information are invalid and cannot be used for the transmission of the first portion of acknowledgement information, the first portion of acknowledgement information indicating an acknowledgement status of a respective instance of the downlink communication resources, in response to determining that the uplink communication resources allocated for the transmission of the first portion of acknowledgement information are invalid, to select second uplink communication resources, and to receive the first portion of acknowledgement information transmitted using the selected second uplink communication resources.

References

[1] 3GPP TS 38.300 v. 15.2.0 “NR; NR and NG-RAN Overall Description; Stage 2(Release 15)”, June 2018

[2] Holma H. and Toskala A, “LTE for UMTS OFDMA and SC-FDMA based radio access”, John Wiley and Sons, 2009 [3] 3GPP TR 38.913, “Study on Scenarios and Requirements for Next Generation Access Technologies (Release 14)”, vl4.3.0

[4] 3GPP Tdoc RP- 190726, “Physical layer enhancements for NR ultra-reliable and low latency communication (URLLC),” Huawei, HiSilicon, RAN#83 [5] 3GPP Tdoc RP -201310, “Revised WID: Enhanced Industrial Internet of Things (loT) and ultrareliable and low latency communication (URLLC) support for NR,” Nokia, Nokia Shanghai Bell, RAN#88e

[6] 3GPP Tdoc Rl-2008842, "HARQ - ACK Feedback Enhancements for URLLC/IIoT," Nokia, Nokia Shanghai Bell, RANl#103e [7] 3GPP Tdoc R1 -2008984, "Discussion on prioritized UE HARQ feedback enhancements for

URLLC/IIoT," Intel, RANl#103e

[8] European patent application EP20202915.3

[9] 3GPP TS 38.213 “NR; Physical layer procedures for control”, version 16.4.0

Claims

37 CLAIMS What is claimed is:

1. A method of transmitting control information by a communications device in a wireless communications network, the method comprising receiving from an infrastructure equipment of the wireless communications network an indication of a plurality of instances of downlink communications resources associated with a semi-persistent resource allocation, the plurality of instances of downlink communications resources allocated for the transmission of data by the infrastructure equipment to the communications device via a wireless access interface, determining that uplink communication resources allocated for the transmission of a first portion of acknowledgement information is invalid and cannot be used for the transmission of the first portion of acknowledgement information, the first portion of acknowledgement information indicating an acknowledgement status of a respective instance of the downlink communication resources, in response to determining that the uplink communication resources allocated for the transmission of the first portion of acknowledgement information are invalid, selecting second uplink communication resources, and transmitting the first portion of acknowledgement information using the selected second uplink communication resources.

2. A method according to claim 1, the method comprising determining that one or more instances of uplink communication resources allocated for the transmission of portions of acknowledgement information including the first portion of acknowledgment information are invalid and cannot be used for the transmission of the acknowledgement information.

3. A method according to claim 2, wherein selecting the second uplink communication resources is in response to determining that the number of the instances of uplink communication resources allocated for the transmission of portions of acknowledgement information which are invalid exceeds a first predetermined threshold.

4. A method according to claim 2, the method comprising determining a number of portions of acknowledgement information for which the one or more instances of uplink communication resources were allocated, and determining that the number of portions of acknowledgement information exceeds a second predetermined threshold, wherein selecting the second uplink communication resources is in response to determining that the number of portions of acknowledgement information exceeds the second predetermined threshold.

5. A method according to claim 2, the method comprising determining that the one or more instances of uplink communication resources meet predetermined criteria.

6. A method according to claim 5, wherein an instance of uplink communication resources meets the predetermined criteria if the instance of uplink communication resources was allocated for the 38 transmission of acknowledgement information associated with downlink data, and the downlink data meets second predetermined criteria.

7. A method according to claim 6, wherein downlink data meets the second predetermined criteria if it is associated with a first logical channel.

8. A method according to claim 6, wherein downlink data meets the second predetermined criteria if it is associated with a first physical layer priority.

9. A method according to claim 7, the method comprising receiving an indication of the second predetermined criteria, the indication transmitted by the infrastructure equipment using radio resource control (RRC) signalling.

10. A method according to claim 1, the method comprising receiving a trigger indication, the trigger indication transmitted using an instance of the downlink communications resources associated with a semi-persistent resource allocation, wherein selecting the second uplink communication resources is in response to receiving the trigger indication.

11. A method according to claim 10, wherein the trigger indication is indicated in a medium access control (MAC) control element (CE) transmitted by the infrastructure equipment using the instance of the downlink communication resources.

12. A method according to claim 1, wherein no indication of the second uplink communication resources is received after the respective instance of the downlink communication resources.

13. A method according to claim 1, wherein the second uplink communication resources are on a physical uplink shared channel.

14. A method according to claim 1, wherein the second uplink communication resources are on a physical uplink control channel.

15. A method according to claim 1, wherein the selecting the second uplink communication resources is based on one or more first parameters indicated in radio resource control (RRC) signalling transmitted by the infrastructure equipment before the respective instance of the downlink communication resources.

16. A method according to claim 1, wherein the selecting the second uplink communication resources is based on one or more second parameters indicated in signalling transmitted by the infrastructure equipment using the respective instance of the downlink communication resources.

17. A method according to claim 16, wherein the second parameters are indicated in a medium access control (MAC) control element (CE) transmitted by the infrastructure equipment using the respective instance of the downlink communication resources.

18. A method according to claim 1, wherein the selecting the second uplink communication resources is based on the uplink communication resources allocated for the transmission of the first portion of acknowledgement information.

19. A method according to claim 1, wherein the selecting the second uplink communication resources is based on a predetermined number of slots or sub-slots between a slot or sub-slot containing the uplink communication resources allocated for the transmission of the first portion of acknowledgement information and a slot or sub-slot containing the second uplink communication resources.

20. A method according to claim 19, wherein the predetermined number of slots or sub-slots is common to a plurality of semi-persistent resource allocations.

21. A method according to claim 19, the method comprising receiving an indication of the predetermined number of slots or sub-slots.

22. A method according to claim 21, wherein the indication of the predetermined number of slots or sub-slots is transmitted by the infrastructure equipment in RRC signalling.

23. A method according to claim 21, wherein the indication of the predetermined number of slots or sub-slots is transmitted by the infrastructure in a downlink control information (DCI)

24. A method according to claim 1, wherein the second uplink communication resources is selected from a plurality of periodic resource instances.

25. A method according to claim 1, wherein the second uplink communication resources consist of a plurality of instances of uplink communication resources.

26. A method according to claim 25, wherein the number of instances in the plurality of instances of uplink communication resources is predetermined.

27. A method according to claim 25, the method comprising receiving a termination indicator transmitted by the infrastructure equipment at a time, the termination indicator indicating that none of the plurality of instances of uplink communication resources occurs after the time.

28. A method according to claim 25, the method comprising determining that one of the plurality of instances of uplink communication resources is invalid and in response to determining that one of the plurality of instances of uplink communication resources is invalid, refraining from transmitting acknowledgement information using the one of the plurality of instances of uplink communication resources which is invalid.

29. A method according to claim 1, the method comprising selecting one or more portions of acknowledgement information including the first portion of acknowledgement information for transmission using the second uplink communication resources.

30. A method according to claim 29, the method comprising determining a number of the plurality of instances of uplink communication resources required to transmit the selected one or more portions of acknowledgement information, wherein the transmitting the first portion of acknowledgement information using the second uplink communication resources is by transmitting the selected portions of acknowledgement information using the determined number of the plurality of instances of uplink communication resources.

31. A method according to claim 29, the method comprising encoding the one or more portions of acknowledgement information in accordance with a codebook for transmitting multiple portions of acknowledgement information using a single instance of communication resources, wherein transmitting the first portion of acknowledgement information using the second uplink communication resources is by transmitting the encoded the one or more portions of acknowledgement information.

32. A method according to claim 29, wherein the selecting the one or more portions of acknowledgement information comprises selecting acknowledgement information for each of a plurality of configured hybrid automatic repeat request (HARQ) processes.

33. A method according to claim 29, wherein the selecting the one or more portions of acknowledgement information comprises selecting acknowledgement information associated with a plurality of semi-persistent resource allocations, including the semi-persistent resource allocation.

34. A method according to claim 29, wherein the selecting the one or more portions of acknowledgement information comprises selecting acknowledgement information associated with one or more semi-persistent resource allocations allocated for the transmission of data which meets the second predetermined criteria, including the semi-persistent resource allocation.

35. A method according to claim 29, wherein the selecting the one or more portions of acknowledgement information comprises selecting acknowledgement information associated with one or more semi-persistent resource allocations which meet third predetermined criteria, including the semi- persistent resource allocation.

36. A method according to claim 29, wherein the selecting the one or more portions of acknowledgement information comprises selecting only dropped acknowledgement information.

37. A method according to claim 1, the method comprising receiving a MAC CE comprising an indication, for each of one or more semi-persistent resource allocations, of whether acknowledgement information associated with the semi-persistent resource allocation may be selected for transmission using the second uplink communication resources.

38. A method of receiving at an infrastructure equipment control information transmittted by a communications device in a wireless communications network, the method comprising transmitting an indication of a plurality of instances of downlink communications resources associated with a semi-persistent resource allocation, the plurality of instances of downlink communications resources allocated for the transmission of data by the infrastructure equipment to the communications device via a wireless access interface, determining that uplink communication resources allocated for the transmission of a first portion of acknowledgement information are invalid and cannot be used for the transmission of the first portion of acknowledgement information, the first portion of acknowledgement information indicating an acknowledgement status of a respective instance of the downlink communication resources, in response to determining that the uplink communication resources allocated for the transmission of the first portion of acknowledgement information are invalid, selecting second uplink communication resources, and receiving the first portion of acknowledgement information transmitted using the selected second uplink communication resources.

39. A communications device for operating in a wireless communications network, the communications device comprising a transmitter configured to transmit signals on a wireless access interface provided by an infrastructure equipment of the wireless communications network, a receiver configured to receive signals on the wireless access interface, and a controller configured to control the transmitter and the receiver so that the communications device is operable to receive from the infrastructure equipment an indication of a plurality of instances of downlink communications resources associated with a semi-persistent resource allocation, the plurality of instances of downlink communications resources allocated for the transmission of data by the infrastructure equipment to the communications device via a wireless access interface, to determine that uplink communication resources allocated for the transmission of a first portion of acknowledgement information is invalid and cannot be used for the transmission of the first portion of acknowledgement information, the first portion of acknowledgement information indicating an acknowledgement status of a respective instance of the downlink communication resources, in response to determining that the uplink communication resources allocated for the transmission of the first portion of acknowledgement information are invalid, to select second uplink communication resources, and to transmit the first portion of acknowledgement information using the selected second uplink communication resources.

40. Circuitry for a communications device for operating in a wireless communications network, the circuitry comprising transmitter circuitry configured to transmit signals on a wireless access interface provided by an infrastructure equipment of the wireless communications network, receiver circuitry configured to receive signals on the wireless access interface, and controller circuitry configured to control the transmitter circuitry and the receiver circuitry so that the communications device is operable to receive from the infrastructure equipment an indication of a plurality of instances of downlink communications resources associated with a semi-persistent resource allocation, the plurality of instances of downlink communications resources allocated for the transmission of data by the infrastructure equipment to the communications device via a wireless access interface, to determine that uplink communication resources allocated for the transmission of a first portion of acknowledgement information is invalid and cannot be used for the transmission of the first portion of acknowledgement information, the first portion of acknowledgement information indicating an acknowledgement status of a respective instance of the downlink communication resources, 42 in response to determining that the uplink communication resources allocated for the transmission of the first portion of acknowledgement information are invalid, to select second uplink communication resources, and to transmit the first portion of acknowledgement information using the selected second uplink communication resources.

41. Infrastructure equipment for use in a wireless communications network, the infrastructure equipment providing a wireless access interface, the infrastructure equipment comprising a transmitter configured to transmit signals via the wireless access interface, a receiver configured to receive signals, and a controller configured to control the transmitter and the receiver so that the infrastructure equipment is operable to transmit to a communications device an indication of a plurality of instances of downlink communications resources associated with a semi-persistent resource allocation, the plurality of instances of downlink communications resources allocated for the transmission of data by the infrastructure equipment to the communications device via the wireless access interface, to determine that uplink communication resources allocated for the transmission of a first portion of acknowledgement information are invalid and cannot be used for the transmission of the first portion of acknowledgement information, the first portion of acknowledgement information indicating an acknowledgement status of a respective instance of the downlink communication resources, in response to determining that the uplink communication resources allocated for the transmission of the first portion of acknowledgement information are invalid, to select second uplink communication resources, and to receive the first portion of acknowledgement information transmitted using the selected second uplink communication resources.

42. Circuitry for infrastructure equipment for use in a wireless communications network, the infrastructure equipment providing a wireless access interface, the circuitry comprising transmitter circuitry configured to transmit signals via the wireless access interface, receiver circuitry configured to receive signals, and controller circuitry configured to control the transmitter circuitry and the receiver circuitry so that the infrastructure equipment is operable to transmit to a communications device an indication of a plurality of instances of downlink communications resources associated with a semi-persistent resource allocation, the plurality of instances of downlink communications resources allocated for the transmission of data by the infrastructure equipment to the communications device via the wireless access interface, to determine that uplink communication resources allocated for the transmission of a first portion of acknowledgement information are invalid and cannot be used for the transmission of the first portion of acknowledgement information, the first portion of acknowledgement information indicating an acknowledgement status of a respective instance of the downlink communication resources, in response to determining that the uplink communication resources allocated for the transmission of the first portion of acknowledgement information are invalid, to select second uplink communication resources, and to receive the first portion of acknowledgement information transmitted using the selected second uplink communication resources.