Patent Description:
The present disclosure relates to wireless communications, and in particular, to PUCCH carrier switching such as, for example, HARQ based and/or associated PUCCH carrier switching.

The Third Generation Partnership Project (3GPP) has developed and is developing standards for Fourth Generation (<NUM>) (also referred to as Long Term Evolution (LTE)) and Fifth Generation (<NUM>) (also referred to as New Radio (NR)) wireless communication systems. Such systems provide, among other features, broadband communication between network nodes, such as base stations, and mobile wireless devices (WD), as well as communication between network nodes and between WDs.

The NR standard in 3GPP is designed to provide service for multiple use cases such as enhanced mobile broadband (eMBB), ultra-reliable and low latency communication (URLLC), and machine type communication (MTC). Each of these services has different technical requirements. For example, the general requirement for eMBB is high data rate with moderate latency and moderate coverage, while URLLC service requires a low latency and high reliability transmission but perhaps for moderate data rates.

One of the solutions for low latency data transmission is shorter transmission time intervals. In NR, in addition to transmission in a slot, a mini-slot transmission is also allowed to reduce latency. A mini-slot is a concept that is used in scheduling and in downlink (DL) a min-slot can consist of <NUM>, <NUM> or <NUM> Orthogonal Frequency Division Multiplexing (OFDM) symbols, while in uplink (UL) a mini-slot can be any number of <NUM> to <NUM> OFDM symbols. The concepts of slot and mini-slot are not specific to a specific service meaning that a mini-slot may be used for either eMBB, URLLC, or other services. <FIG> is a diagram of an example radio resource in NR.

In the 3GPP NR standard, downlink control information (DCI), which is transmitted in physical downlink control channel (PDCCH), is used to indicate the DL data related information, UL related information, power control information, slot format indication, etc. There are different formats of DCI associated with each of these control signals and the wireless device identifies them based on different radio network temporary identifiers (RNTIs).

The wireless device is configured by higher layer signaling to monitor for DCIs in different resources with different periodicities, etc. DCI formats 1_0, 1_1, and 1_2 are used for scheduling DL data which is sent in physical downlink shard channel (PDSCH), and includes time and frequency resources for DL transmission, as well as modulation and coding information, HARQ (hybrid automatic repeat request) information, etc..

In cases of DL semi-persistent scheduling (SPS) and UL configured grant type <NUM>, part of the scheduling includes the periodicity is provided by the higher layer configurations, while the rest of scheduling information such as time domain and frequency domain resource allocation, modulation and coding, etc., are provided by the DCI in PDCCH.

Uplink control information (UCI) is control information sent by a wireless device to a network node. UCI may include:.

UCI is typically transmitted on physical uplink control channel (PUCCH). However, if the wireless device is transmitting data on the PUSCH with a valid PUSCH resource overlapping with PUCCH, UCI can be multiplexed with UL data and transmitted on PUSCH instead, if the timeline requirements for UCI multiplexing is met.

Physical Uplink Control Channel (PUCCH) is used by the wireless device to a transmit HARQ-ACK feedback message corresponding to the reception of DL data transmission. It is also used by the wireless device to send channel state information (CSI) or to request for an uplink grant for transmitting UL data.

In NR, there exist multiple PUCCH formats supporting different UCI payload sizes. PUCCH formats <NUM> and <NUM> support UCI up to <NUM> bits, while PUCCH formats <NUM>, <NUM>, and <NUM> can support UCI of more than <NUM> bits. In terms of PUCCH transmission duration, PUCCH formats <NUM> and <NUM> are considered short PUCCH formats supporting PUCCH duration of <NUM> or <NUM> OFDM symbols, while PUCCH formats <NUM>, <NUM> and <NUM> are considered as long formats and can support PUCCH duration from <NUM> to <NUM> symbols.

An example procedure for receiving downlink transmission is that the wireless device first monitors and decodes a physical downlink control channel (PDCCH) in slot n which points to a DL data scheduled in slot n+K<NUM> slots (K<NUM> is larger than or equal to <NUM>). The wireless device then decodes the data in the corresponding physical downlink shared channel (PDSCH). Finally, based on the outcome of the decoding, the wireless device sends an acknowledgement of the correct decoding (ACK) or a negative acknowledgement (NACK) to the network node at time slot n+ K<NUM>+K<NUM> (in case of slot aggregation n+ K<NUM> would be replaced by the slot where PDSCH ends). Both of K<NUM> and K<NUM> are indicated in the DCI. The resources for sending the acknowledgement are indicated by PUCCH resource indicator (PRI) field in the DCI which points to one of PUCCH resources that are configured by higher layers.

Depending on DL/UL slot configurations, or whether carrier aggregation, or per codeblock group (CBG) transmission used in the DL, the feedback for several PDSCHs may need to be multiplexed in one feedback. This is performed by constructing HARQ-ACK codebooks. In NR, the wireless device can be configured to multiplex the Ack/Nack (A/N) bits using a semi-static codebook or a dynamic codebook.

Type <NUM> or semi-static codebook includes a bit sequence where each element contains the A/N bit from a possible allocation in a certain slot, carrier, or transport block (TB). When the wireless device is configured with a code block group (CBG) and/or time-domain resource allocation (TDRA) table with multiple entries, multiple bits are generated per slot and transport block TB (as discussed below). The codebook is derived regardless of the actual PDSCH scheduling. The size and format of the semi-static codebook is preconfigured based on the mentioned parameters. The drawback of semi-static HARQ ACK codebook is that the size is fixed, and regardless of whether there is a transmission or not, a bit is reserved in the feedback matrix.

In cases when a wireless device has a TDRA table with multiple time-domain resource allocation entries configured, the table may be pruned (i.e., entries are removed based on a specified algorithm) to derive a TDRA table that only contains non-overlapping time-domain allocations. One bit is then reserved in the HARQ CB for each non-overlapping entry (assuming a wireless device is capable of supporting reception of multiple PDSCH in a slot).

To help avoid reserving unnecessary bits in a semi-static HARQ codebook, in NR a wireless device can be configured to use a type <NUM> or dynamic HARQ codebook, where an A/N bit is present only if there is a corresponding transmission scheduled. To help avoid any confusion between the network node and the wireless device, on the number of PDSCHs that the wireless device has to send a feedback for, a counter downlink assignment indicator (DAI) field exists in DL assignment, which denotes an accumulative number of {serving cell, PDCCH occasion} pairs in which a PDSCH is scheduled to a wireless device up to the current PDCCH. In addition to that, there is another field called total DAI, which when present indicates the total number of {serving cell, PDCCH occasion} up to (and including) all PDCCHs of the current PDCCH monitoring occasion. The timing for sending HARQ feedback is determined based on both PDSCH transmission slot with reference to PDCCH slot (K<NUM>) and the PUCCH slot that contains HARQ feedback (K<NUM>).

<FIG> illustrates the timeline in an example scenario with two PDSCHs and one feedback. In this example there is in total <NUM> PUCCH resources configured, and the PRI (e.g., PUCCH resource indicator) indicates PUCCH <NUM> to be used for HARQ feedback. The following describes how PUCCH <NUM> is selected from <NUM> PUCCH resources based on the procedure described in 3GPP standards such as in, for example, 3GPP Release <NUM> (Rel-<NUM>, also referred to as NR Rel-<NUM>).

In 3GPP NR Rel-<NUM>, a wireless device can be configured with maximum <NUM> PUCCH resource sets for transmission of HARQ-ACK information. Each set is associated with a range of UCI payload bits including HARQ-ACK bits. The first set is always associated to <NUM> or <NUM> HARQ-ACK bits and hence includes only PUCCH format <NUM> or <NUM> or both. The range of payload values (minimum of maximum values) for other sets, if configured, is provided by configuration except the maximum value for the last set where a default value is used, and the minimum value of the second set being <NUM>. The first set can include a maximum of <NUM> PUCCH resources of PUCCH format <NUM> or <NUM>. Other sets can include maximum <NUM> bits of format <NUM> or <NUM> or <NUM>.

As previously described, the wireless device determines a slot for transmission of HARQ-ACK bits in a PUCCH corresponding to PDSCHs scheduled or activated by DCI via value provided by configuration or a field in the corresponding DCI. The wireless device forms a codebook from the HARQ-ACK bits with associated PUCCH in a same slot via corresponding values. The wireless device determines a PUCCH resource set where the size of the codebook is within the corresponding range of payload values associated to that set. The wireless device determines a PUCCH resource in that set if the set is configured with maximum <NUM> PUCCH resources, by a field in the last DCI associated to the corresponding PDSCHs. If the set is the first set and is configured with more than <NUM> resources, a PUCCH resource in that set is determined by a field in the last DCI associated to the corresponding PDSCHs and implicit rules based on the control channel element (CCE).

A PUCCH resource for HARQ-ACK transmission can overlap in time with other PUCCH resources for channel state information (CSI) and/or scheduling request (SR) transmissions as well as PUSCH transmissions in a slot. In case of overlapping PUCCH and/or PUSCH resources, first the wireless device resolves overlapping between PUCCH resources, if any, by determining a PUCCH resource carrying the total UCI (including HARQ-ACK bits) such that the UCI multiplexing timeline requirements are met. There might be partial or completely dropping of CSI bits, if any, to multiplex the UCI in the determined PUCCH resource. Then, the wireless device resolves overlapping between PUCCH and PUSCH resources, if any, by multiplexing the UCI on the PUSCH resource if the timeline requirements for UCI multiplexing are met.

In NR, when operating with carrier aggregation (CA), as a baseline, the HARQ-ACK feedback information (carried in a physical uplink control channel, PUCCH) for multiple downlink component carriers (CC) are transmitted on the primary cell (PCell). This is to support asymmetric CA with the number of downlink carriers unrelated to the number of uplink carriers.

For a large number of downlink CCs, a single uplink carrier may have to carry a large number of HARQ-ACK feedbacks. Thus, to avoid overloading a single carrier, it is possible to configure two PUCCH groups (set of serving cells) where feedbacks relating to DL transmissions in the first PUCCH group is transmitted in the uplink of the PCell within the first PUCCH group, and feedbacks relating to the other PUCCH group is transmitted on the primary second cell (PSCell) or on a PUCCH-SCell of the second PUCCH group.

It is possible to use other UL cells for HARQ-ACK feedback transmission by semistatically configuring a serving cell ID indicating a cell within the same PUCCH group to use for the HARQ-ACK transmission. However, such configuration is only possible for a newly added SCell. That is, for DL transmission on a PCell, HARQ-ACK transmission is only possible on the PCell.

<FIG> is a diagram of an example of a HARQ-ACK feedback transmission mechanism with two PUCCH groups, in which the HARQ-ACK feedback for the first <NUM> DL CCs is transmitted in the UL PCell in the corresponding PUCCH group and the feedback for the last <NUM> DL CCs is transmitted in the PUCCH-SCell of the second PUCCH group.

As used herein, the term "carrier" and "cell" are used interchangeably and understood to have a similar meaning.

Different methods for PUCCH carrier switching have been discussed. They may be classified into two example approaches, namely dynamic carrier switching and semi-static switching. The dynamic approach includes having a dynamic indication from the network node, e.g., in the form of dedicate indication field in the DCI, while the semi-static approach may rely on some semi-static rule or semi-static reconfiguration.

A wireless device can be indicated or configured with the HARQ-ACK timing value, such as with K<NUM>, for a SPS configuration. This HARQ-ACK timing value is applied to all SPS PDSCH occasions of the activated SPS configuration.

In TDD operation with asymmetric DL/UL TDD pattern, if short SPS periodicity is used, it can happen that the SPS periodicity value does not match with the TDD pattern, when it comes to HARQ-ACK feedback timing. It may happen that the HARQ-ACK timing value does not indicate a valid UL slot for all SPS PDSCH occasions. This is illustrated in <FIG> with a single SPS configuration with periodicity of <NUM> slot where the indicated does not match with the 'DDDU' semi-static TDD pattern, i.e., where would occur mismatch of SPS periodicity and TDD pattern. In the TDD pattern, "D" indicates downlink and "U" indicates uplink. With K<NUM> =<NUM> slots, HARQ-ACK feedback for the second and third SPS occasions would fall into DL slots, and thus these HARQ-ACK would be dropped.

It has been proposed to attempt to solve above issue by allowing SPS HARQ-ACK, which would otherwise be dropped, to be deferred to a next available UL slot instead, as described in 3GPP.

There are two type of DAIs that can be signaled in DCI. The DAI is used so the wireless device can detect missed PDCCH transmissions scheduling PDSCH reception, SPS PDSCH release, or SCell dormancy indication. The signaled DAIs are then used to construct a Type-<NUM> HARQ codebook containing detected PDSCH receptions, SPS PDSCH releases and SCell dormancy indications. There are two types of DAI, a counter DAI that is increased for each PDCCH containing a PDSCH reception, SPS PDSCH release or SCell dormancy indication, and a total DAI that denotes the total number of such PDCCHs transmitted to the wireless device up to the current PDCCH monitoring occasion.

However, the existing behavior of HARQ-ACK feedbacks is too restrictive in some scenarios, especially when the delay of HARQ-ACK transmission is of very high importance. For example, the PCell or PUCCH-SCell or the configured UL cell for HARQ-ACK may not have a TDD pattern suitable for fast HARQ-ACK feedback and thus causing a delay bottleneck for the overall DL transmission. Allowing PUCCH carrier switching can then be useful to address such issue, but it is not clear how to support PUCCH carrier switching. In addition, when supported, there will be impacts on different aspects such as HARQ-ACK codebook that need to be resolved.

Existing methods are disclosed in MEDIATEK INC: "On UE feedback enhancements for HARQ-ACK",3GPP DRAFT; R1-<NUM>, <NUM> January <NUM>, NEC: "UE feedback enhancements for HARQ-ACK", 3GPP DRAFT; R1-<NUM><NUM> January <NUM>, QUALCOMM INCORPORATED: "HARQ-ACK enhancement for IOT and URLLC", 3GPP DRAFT; R1-<NUM>, <NUM> January <NUM>, and MODERATOR (NOKIA): "Moderator summary #<NUM> on HARQ-ACK feedback enhancements for NR Rel-<NUM> URLLC/ IIoT", 3GPP DRAFT; R1-<NUM>, <NUM> February <NUM>.

Before describing in detail example embodiments, it is noted that the embodiments reside primarily in combinations of apparatus components and processing steps related to PUCCH carrier switching such as, for example, HARQ based PUCCH carrier switching. Accordingly, components have been represented where appropriate by conventional symbols in the drawings, showing only those specific details that are pertinent to understanding the embodiments so as not to obscure the disclosure with details that will be readily apparent to those of ordinary skill in the art having the benefit of the description herein.

In some embodiments, the phrase at least one of A and B corresponds to A and/or B.

The term "network node" used herein can be any kind of network node comprised in a radio network which may further comprise any of base station (BS), radio base station, base transceiver station (BTS), base station controller (BSC), radio network controller (RNC), g Node B (gNB), evolved Node B (eNB or eNodeB), Node B, multi-standard radio (MSR) radio node such as MSR BS, multi-cell/multicast coordination entity (MCE), integrated access and backhaul (IAB) node, relay node, donor node controlling relay, radio access point (AP), transmission points, transmission nodes, Remote Radio Unit (RRU) Remote Radio Head (RRH), a core network node (e.g., mobile management entity (MME), self-organizing network (SON) node, a coordinating node, positioning node, MDT node, etc.), an external node (e.g., 3rd party node, a node external to the current network), nodes in distributed antenna system (DAS), a spectrum access system (SAS) node, an element management system (EMS), etc. The network node may also comprise test equipment. The term "radio node" used herein may be used to also denote a wireless device (WD) such as a wireless device (WD) or a radio network node.

The WD may also be a radio communication device, target device, device to device (D2D) WD, machine type WD or WD capable of machine to machine communication (M2M), low-cost and/or low-complexity WD, a sensor equipped with WD, Tablet, mobile terminals, smart phone, laptop embedded equipped (LEE), laptop mounted equipment (LME), USB dongles, Customer Premises Equipment (CPE), an Internet of Things (IoT) device, or a Narrowband IoT (NB-IOT) device, etc..

One or more embodiments detailed in the present disclosure are described in general and can be applied to both slot-based PUCCH and sub-slot based PUCCH configuration. It applies to both HARQ-ACK feedback of dynamically scheduled PDSCH and that of DL SPS.

The term "carrier" and "cell" are used with similar meanings in the context of the present disclosure.

Transmitting in downlink may pertain to transmission from the network or network node to the wireless device. Transmitting in uplink may pertain to transmission from the wireless device to the network or network node. Transmitting in sidelink may pertain to (direct) transmission from one wireless device to another. Uplink, downlink and sidelink (e.g., sidelink transmission and reception) may be considered communication directions. In some variants, uplink and downlink may also be used to described wireless communication between network nodes, e.g. for wireless backhaul and/or relay communication and/or (wireless) network communication for example between base stations or similar network nodes, in particular communication terminating at such. It may be considered that backhaul and/or relay communication and/or network communication is implemented as a form of sidelink or uplink communication or similar thereto.

Some embodiments provide PUCCH carrier switching such as, for example, HARQ based PUCCH carrier switching.

Referring again to the drawing figures, in which like elements are referred to by like reference numerals, there is shown in <FIG> a schematic diagram of a communication system <NUM>, according to an embodiment, such as a 3GPP-type cellular network that may support standards such as LTE and/or NR (<NUM>), which comprises an access network <NUM>, such as a radio access network, and a core network <NUM>. The access network <NUM> comprises a plurality of network nodes 16a, 16b, 16c (referred to collectively as network nodes <NUM>), such as NBs, eNBs, gNBs or other types of wireless access points, each defining a corresponding coverage area 18a, 18b, 18c (referred to collectively as coverage areas <NUM>). Each network node 16a, 16b, 16c is connectable to the core network <NUM> over a wired or wireless connection <NUM>. A first wireless device (WD) 22a located in coverage area 18a is configured to wirelessly connect to, or be paged by, the corresponding network node 16a. A second WD 22b in coverage area 18b is wirelessly connectable to the corresponding network node 16b. While a plurality of WDs 22a, 22b (collectively referred to as wireless devices <NUM>) are illustrated in this example, the disclosed embodiments are equally applicable to a situation where a sole WD is in the coverage area or where a sole WD is connecting to the corresponding network node <NUM>. Note that although only two WDs <NUM> and three network nodes <NUM> are shown for convenience, the communication system may include many more WDs <NUM> and network nodes <NUM>.

The communication system <NUM> may itself be connected to a host computer <NUM>, which may be embodied in the hardware and/or software of a standalone server, a cloudimplemented server, a distributed server or as processing resources in a server farm.

A network node <NUM> is configured to include an indication unit <NUM> which is configured to perform one or more network node <NUM> functions as described herein such as with respect to PUCCH carrier switching such as, for example, HARQ based PUCCH carrier switching. A wireless device <NUM> is configured to include a switching unit <NUM> which is configured to perform one or more wireless device <NUM> functions as described herein such as with respect to PUCCH carrier switching such as, for example, HARQ based PUCCH carrier switching.

The host application <NUM> may be operable to provide a service to a remote user, such as a WD <NUM> connecting via an OTT connection <NUM> terminating at the WD <NUM> and the host computer <NUM>. The "user data" may be data and information described herein as implementing the described functionality. In one embodiment, the host computer <NUM> may be configured for providing control and functionality to a service provider and may be operated by the service provider or on behalf of the service provider. The processing circuitry <NUM> of the host computer <NUM> may enable the host computer <NUM> to observe, monitor, control, transmit to and/or receive from the network node <NUM> and or the wireless device <NUM>. The processing circuitry <NUM> of the host computer <NUM> may include an information unit <NUM> configured to enable the service provider to analyze, store, forward, relay, transmit, receive, determine, configure, etc., information related to PUCCH carrier switching such as, for example, HARQ based PUCCH carrier switching.

Thus, the network node <NUM> further has software <NUM> stored internally in, for example, memory <NUM>, or stored in external memory (e.g., database, storage array, network storage device, etc.) accessible by the network node <NUM> via an external connection. The processing circuitry <NUM> may be configured to control any of the methods and/or processes described herein and/or to cause such methods, and/or processes to be performed, e.g., by network node <NUM>. Processor <NUM> corresponds to one or more processors <NUM> for performing network node <NUM> functions described herein. The memory <NUM> is configured to store data, programmatic software code and/or other information described herein. In some embodiments, the software <NUM> may include instructions that, when executed by the processor <NUM> and/or processing circuitry <NUM>, causes the processor <NUM> and/or processing circuitry <NUM> to perform the processes described herein with respect to network node <NUM>. For example, processing circuitry <NUM> of the network node <NUM> may include indication unit <NUM> configured to perform one or more network node <NUM> functions as described herein such as with respect to PUCCH carrier switching such as, for example, HARQ based PUCCH carrier switching.

The processing circuitry <NUM> may be configured to control any of the methods and/or processes described herein and/or to cause such methods, and/or processes to be performed, e.g., by WD <NUM>. The processor <NUM> corresponds to one or more processors <NUM> for performing WD <NUM> functions described herein. The WD <NUM> includes memory <NUM> that is configured to store data, programmatic software code and/or other information described herein. In some embodiments, the software <NUM> and/or the client application <NUM> may include instructions that, when executed by the processor <NUM> and/or processing circuitry <NUM>, causes the processor <NUM> and/or processing circuitry <NUM> to perform the processes described herein with respect to WD <NUM>. For example, the processing circuitry <NUM> of the wireless device <NUM> may include a switching unit <NUM> configured to perform one or more wireless device <NUM> functions as described herein such as with respect to PUCCH carrier switching such as, for example, HARQ based PUCCH carrier switching.

In some embodiments, the measurements may be implemented in that the software <NUM>, <NUM> causes messages to be transmitted, in particular empty or 'dummy' messages, using the OTT connection <NUM> while it monitors propagation times, errors, etc..

Although <FIG> and <FIG> show various "units" such as indication unit <NUM>, and switching unit <NUM> as being within a respective processor, it is contemplated that these units may be implemented such that a portion of the unit is stored in a corresponding memory within the processing circuitry. In other words, the units may be implemented in hardware or in a combination of hardware and software within the processing circuitry.

<FIG> is a flowchart illustrating an example method implemented in a communication system, such as, for example, the communication system of <FIG> and <FIG>, in accordance with one embodiment. The communication system may include a host computer <NUM>, a network node <NUM> and a WD <NUM>, which may be those described with reference to <FIG>. In a first step of the method, the host computer <NUM> provides user data (Block S100). In an optional substep of the first step, the host computer <NUM> provides the user data by executing a host application, such as, for example, the host application <NUM> (Block S102). In a second step, the host computer <NUM> initiates a transmission carrying the user data to the WD <NUM> (Block S104). In an optional third step, the network node <NUM> transmits to the WD <NUM> the user data which was carried in the transmission that the host computer <NUM> initiated, in accordance with the teachings of the embodiments described throughout this disclosure (Block S106). In an optional fourth step, the WD <NUM> executes a client application, such as, for example, the client application <NUM>, associated with the host application <NUM> executed by the host computer <NUM> (Block S108).

<FIG> is a flowchart illustrating an example method implemented in a communication system, such as, for example, the communication system of <FIG>, in accordance with one embodiment. The communication system may include a host computer <NUM>, a network node <NUM> and a WD <NUM>, which may be those described with reference to <FIG> and <FIG>. In a first step of the method, the host computer <NUM> provides user data (Block S110). In an optional substep (not shown) the host computer <NUM> provides the user data by executing a host application, such as, for example, the host application <NUM>. In a second step, the host computer <NUM> initiates a transmission carrying the user data to the WD <NUM> (Block S112). In an optional third step, the WD <NUM> receives the user data carried in the transmission (Block S114).

<FIG> is a flowchart illustrating an example method implemented in a communication system, such as, for example, the communication system of <FIG>, in accordance with one embodiment. The communication system may include a host computer <NUM>, a network node <NUM> and a WD <NUM>, which may be those described with reference to <FIG> and <FIG>. In an optional first step of the method, the WD <NUM> receives input data provided by the host computer <NUM> (Block S116). In an optional substep of the first step, the WD <NUM> executes the client application <NUM>, which provides the user data in reaction to the received input data provided by the host computer <NUM> (Block S118). Additionally or alternatively, in an optional second step, the WD <NUM> provides user data (Block S120). In an optional substep of the second step, the WD provides the user data by executing a client application, such as, for example, client application <NUM> (Block S122). In providing the user data, the executed client application <NUM> may further consider user input received from the user. Regardless of the specific manner in which the user data was provided, the WD <NUM> may initiate, in an optional third substep, transmission of the user data to the host computer <NUM> (Block S124). In a fourth step of the method, the host computer <NUM> receives the user data transmitted from the WD <NUM>, in accordance with the teachings of the embodiments described throughout this disclosure (Block S126).

<FIG> is a flowchart illustrating an example method implemented in a communication system, such as, for example, the communication system of <FIG>, in accordance with one embodiment. The communication system may include a host computer <NUM>, a network node <NUM> and a WD <NUM>, which may be those described with reference to <FIG> and <FIG>. In an optional first step of the method, in accordance with the teachings of the embodiments described throughout this disclosure, the network node <NUM> receives user data from the WD <NUM> (Block S128). In an optional second step, the network node <NUM> initiates transmission of the received user data to the host computer <NUM> (Block S130). In a third step, the host computer <NUM> receives the user data carried in the transmission initiated by the network node <NUM> (Block S132).

<FIG> is a flowchart of an example process in a network node <NUM> according to some embodiments of the present disclosure. One or more blocks described herein may be performed by one or more elements of network node <NUM> such as by one or more of processing circuitry <NUM> (including the indication unit <NUM>), processor <NUM>, radio interface <NUM> and/or communication interface <NUM>. Network node <NUM> is configured to cause (Block S134) transmission of an indication of a first physical uplink control channel, PUCCH, carrier for dynamic PUCCH carrier switching, as described herein. The network node <NUM> is configured to receive (Block S136) a PUCCH transmission that is based on dynamic PUCCH carrier switching from a second PUCCH carrier to the first PUCCH carrier in accordance with the indication, as described herein.

According to one or more embodiments, the indication is one of: a downlink assignment index, DAI, associated with the first PUCCH carrier; downlink semi-persistent scheduling, DL SPS, configuration associated with the first PUCCH carrier; multiple PUCCH carrier indication for SPS hybrid automatic repeat request-acknowledgement, HARQ-ACK, that is provided in one of an activation downlink control information, DCI and bitmap of PUCCH carrier indices, and an activation DCI for indicating one of a plurality of sequences for PUCCH carrier indices to select where the plurality of sequences being configured via radio resource control, RRC, signaling, as described herein. According to one or more embodiments, the processing circuitry <NUM> is further configured to cause transmission of an indication that a semi-persistent scheduling, SPS, hybrid automatic repeat request-acknowledgement, HARQ-ACK, deferral is enabled for the second PUCCH carrier where the dynamic PUCCH carrier switching is performed instead of the SPS HARQ-ACK deferral, as described herein.

According to one or more embodiments, the dynamic PUCCH carrier switching is based at least on a physical downlink shared channel, PDSCH,-to- hybrid automatic repeat request-acknowledgement, HARQ, feedback timing indicator. According to one or more embodiments, the PDSCH-to-HARQ feedback timing indicator one of indicates a HARQ-ACK timing value with respect to one of a default PUCCH carrier and other PUCCH carrier, indicates an invalid slot for PUCCH transmission, the processing circuitry is further configured to receive the PUCCH transmission on a PUCCH carrier with a lowest carrier index of a plurality of valid PUCCH carriers, receive the PUCCH transmission on a PUCCH carrier with a highest carrier index of the plurality of valid PUCCH carriers, and receive the PUCCH transmission on a first listed PUCCH carrier of the plurality of valid PUCCH carriers, and takes into account different subcarrier spacing, SCS, among downlink, DL, and uplink, UL, carriers. According to one or more embodiments, the dynamic PUCCH carrier switching is performed with simultaneous PUCCH and physical uplink shared channel, PUSCH, transmissions.

<FIG> is a flowchart of another example process in a network node <NUM> according to some embodiments of the present disclosure. One or more blocks described herein may be performed by one or more elements of network node <NUM> such as by one or more of processing circuitry <NUM> (including the indication unit <NUM>), processor <NUM>, radio interface <NUM> and/or communication interface <NUM>. Network node <NUM> is configured to cause transmission (S138) of a first indication of a first physical uplink control channel, PUCCH, carrier for dynamic PUCCH carrier switching, as described herein. The network node <NUM> is configured to receive (S140) a PUCCH transmission that is based on dynamic PUCCH carrier switching from a second PUCCH carrier to the first PUCCH carrier in accordance with the first indication, as described herein.

According to one or more embodiments, the first indication is one of a downlink assignment index, DAI, associated with the first PUCCH carrier, a downlink semi-persistent scheduling, DL SPS, configuration associated with the first PUCCH carrier, a multiple PUCCH carrier indication for SPS hybrid automatic repeat request-acknowledgement, HARQ-ACK, that is provided in one of an activation downlink control information, DCI, a bitmap of PUCCH carrier indices, and an activation DCI for indicating one of a plurality of sequences for PUCCH carrier indices to select, where the plurality of sequences is configured via radio resource control, RRC, signaling.

According to one or more embodiments, the network node <NUM> is further configured to cause transmission of a second indication that a semi-persistent scheduling, SPS, hybrid automatic repeat request-acknowledgement, HARQ-ACK, deferral is enabled for the second PUCCH carrier, where the dynamic PUCCH carrier switching is performed instead of the SPS HARQ-ACK deferral.

According to one or more embodiments, the dynamic PUCCH carrier switching is based at least on a physical downlink shared channel, PDSCH,-to- hybrid automatic repeat request-acknowledgement, HARQ, feedback timing indicator.

According to one or more embodiments, the PDSCH-to-HARQ feedback timing indicator one of indicates a HARQ-ACK timing value with respect to one of a default PUCCH carrier and other PUCCH carrier, and indicates an invalid slot for PUCCH transmission.

According to one or more embodiments, the network node <NUM> is further configured to receive the PUCCH transmission on a PUCCH carrier with a lowest carrier index of a plurality of valid PUCCH carriers based on the PDSCH-to-HARQ feedback timing indicator, receive the PUCCH transmission on a PUCCH carrier with a highest carrier index of the plurality of valid PUCCH carriers based on the PDSCH-to-HARQ feedback timing indicator, and receive the PUCCH transmission on a first listed PUCCH carrier of the plurality of valid PUCCH carriers.

According to one or more embodiments, the network node <NUM> is further configured to receive a transmission of hybrid automatic repeat request-acknowledgement, HARQ-ACK on the first PUCCH carrier, the transmission being based on a power control command associated with the second PUCCH carrier.

According to one or more embodiments, the network node <NUM> is further configured to transmit to the wireless device an activation downlink control information, DCI, message associated with a physical downlink shared channel, PDSCH, associated with the HARQ-ACK, the DCI message including the power control command.

<FIG> is a flowchart of an example process in a wireless device <NUM> according to some embodiments of the present disclosure. One or more blocks described herein may be performed by one or more elements of wireless device <NUM> such as by one or more of processing circuitry <NUM> (including the switching unit <NUM>), processor <NUM>, radio interface <NUM> and/or communication interface <NUM>. Wireless device <NUM> is configured to receive (Block S140) an indication of a first physical uplink control channel, PUCCH, carrier for dynamic PUCCH carrier switching, as described herein. Wireless device <NUM> is configured to perform (Block S142) dynamic PUCCH carrier switching from a second PUCCH carrier to the first PUCCH carrier based at least on the indication, as described herein.

According to one or more embodiments, the indication is one of: a downlink assignment index, DAI, associated with the first PUCCH carrier, downlink semi-persistent scheduling, DL SPS, configuration associated with the first PUCCH carrier, multiple PUCCH carrier indication for SPS hybrid automatic repeat request-acknowledgement, HARQ-ACK, that is provided in one of: an activation downlink control information, DCI, bitmap of PUCCH carrier indices, and an activation DCI for indicating one of a plurality of sequences for PUCCH carrier indices to select, the plurality of sequences being configured via radio resource control, RRC, signaling. According to one or more embodiments, the processing circuitry is further configured to receive an indication that a semi-persistent scheduling, SPS, hybrid automatic repeat request-acknowledgement, HARQ-ACK, deferral is enabled for the second PUCCH carrier, the dynamic PUCCH carrier switching being performed instead of the SPS HARQ-ACK deferral.

According to one or more embodiments, the dynamic PUCCH carrier switching is based at least on a physical downlink shared channel, PDSCH,-to- hybrid automatic repeat request-acknowledgement, HARQ, feedback timing indicator. According to one or more embodiments, the PDSCH-to-HARQ feedback timing indicator one of: indicates a HARQ-ACK timing value with respect to one of a default PUCCH carrier and other PUCCH carrier, indicates an invalid slot for PUCCH transmission, the processing circuitry is further configured to cause PUCCH transmission on a PUCCH carrier with a lowest carrier index of a plurality of valid PUCCH carriers, cause PUCCH transmission on a PUCCH carrier with a highest carrier index of the plurality of valid PUCCH carriers, cause PUCCH transmission on a first listed PUCCH carrier of the plurality of valid PUCCH carriers, and takes into account different subcarrier spacing, SCS, among downlink, DL, and uplink, UL, carriers. According to one or more embodiments, the dynamic PUCCH carrier switching is performed with simultaneous PUCCH and physical uplink shared channel, transmissions.

<FIG> is a flowchart of another example process in a wireless device <NUM> according to some embodiments of the present disclosure. One or more blocks described herein may be performed by one or more elements of wireless device <NUM> such as by one or more of processing circuitry <NUM> (including the switching unit <NUM>), processor <NUM>, radio interface <NUM> and/or communication interface <NUM>. Wireless device <NUM> is configured to receive (Block S146) a first indication of a first physical uplink control channel, PUCCH, carrier for dynamic PUCCH carrier switching, as described herein. Wireless device <NUM> is configured to perform (Block S148) dynamic PUCCH carrier switching from a second PUCCH carrier to the first PUCCH carrier based at least on the first indication, as described herein.

According to one or more embodiments, the first indication is one of a downlink assignment index, DAI, associated with the first PUCCH carrier, a downlink semi-persistent scheduling, DL SPS, configuration associated with the first PUCCH carrier, a multiple PUCCH carrier indication for SPS hybrid automatic repeat request-acknowledgement, HARQ-ACK, that is provided in one of an activation downlink control information, DCI; and a bitmap of PUCCH carrier indices, and an activation DCI for indicating one of a plurality of sequences for PUCCH carrier indices to select, where the plurality of sequences is configured via radio resource control, RRC, signaling.

According to one or more embodiments, wireless device <NUM> receives a second indication that a semi-persistent scheduling, SPS, hybrid automatic repeat request-acknowledgement, HARQ-ACK, deferral is enabled for the second PUCCH carrier, where the dynamic PUCCH carrier switching is performed instead of the SPS HARQ-ACK deferral.

According to one or more embodiments, the PDSCH-to-HARQ feedback timing indicator one of indicates a HARQ-ACK timing value with respect to one of a default PUCCH carrier and other PUCCH carrier, and indicates an invalid slot for PUCCH transmission; and the wireless device <NUM> is further configured to at least one of cause PUCCH transmission on a PUCCH carrier with a lowest carrier index of a plurality of valid PUCCH carriers based on the PDSCH-to-HARQ feedback timing indicator, cause PUCCH transmission on a PUCCH carrier with a highest carrier index of the plurality of valid PUCCH carriers based on the PDSCH-to-HARQ feedback timing indicator, and cause PUCCH transmission on a first listed PUCCH carrier of the plurality of valid PUCCH carriers based on the PDSCH-to-HARQ feedback timing indicator.

According to one or more embodiments, the dynamic PUCCH carrier switching is performed with simultaneous PUCCH and physical uplink shared channel, PUSCH, transmissions.

According to one or more embodiments, the wireless device <NUM> is further configured to cause a transmission of hybrid automatic repeat request-acknowledgement, HARQ-ACK on the first PUCCH carrier, where the transmission is based on a power control command associated with the second PUCCH carrier.

According to one or more embodiments, the wireless device <NUM> is further configured to receive an activation downlink control information, DCI, message, the activation DCI message including the power control command and being associated with a physical downlink shared channel, PDSCH, associated with the HARQ-ACK.

Having generally described arrangements for PUCCH carrier switching such as, for example, HARQ based PUCCH carrier switching, details for these arrangements, functions and processes are provided as follows, and which may be implemented by the network node <NUM>, wireless device <NUM> and/or host computer <NUM>.

Some embodiments provide for PUCCH carrier switching such as, for example, HARQ based PUCCH carrier switching. A person skilled in the art realizes that other combining embodiments and/or variants are possible in view of the teachings herein. One or more network node <NUM> functions described below may be performed by one or more of processing circuitry <NUM>, processor <NUM>, radio interface <NUM>, indication unit <NUM>, etc. One or more wireless device <NUM> functions described below may be performed by one or more of processing circuitry <NUM>, processor <NUM>, radio interface <NUM>, switching unit <NUM>, etc..

For Type-<NUM> HARQ-ACK codebook, the wireless device <NUM> is provided downlink assignment index (DAI), e.g., counter DAI and total DAI in the DCI scheduling PDSCHs, by network node <NUM>. DAI is used to keep track of the transmitted PDSCHs so that the wireless device <NUM> can adjust the codebook size correctly even if some of the DCI scheduling those PDSCHs are not received by the wireless device <NUM>.

One or more of the following embodiments relate to solutions to support Type-<NUM> HARQ-ACK codebook in the scenario where dynamic PUCCH carrier switching is enabled such as, for example, at wireless device <NUM>. In one non-limiting embodiment, a wireless device <NUM> is provided with downlink assignment index (DAI), e.g., counter DAI and total DAI separately for each PUCCH carrier. In one non-limiting embodiment, the downlink assignment index is associated with a particular PUCCH carrier based on a combination of field(s) indicating the PUCCH carrier and the existing downlink assignment index field in a DCI scheduling PDSCH. In one non-limiting embodiment, a downlink assignment index field in the DCI scheduling PDSCH also includes information about a particular PUCCH carrier with which the downlink assignment index is associated.

In one non-limiting embodiment, Enhanced type-<NUM> HARQ-ACK codebook can be used as follows. In Enhanced Type-<NUM> codebook, a scheduled PDSCH is assigned to a PDSCH group among two PDSCH groups with corresponding downlink assignment index. The framework can be used when there are two carriers to switch between for carrying the HARQ-ACK feedback of the scheduled PDSCHs in a PUCCH group, where each PDSCHs group is associated to one PUCCH carrier, e.g., PDSCH group <NUM> and <NUM> are associated to PUCCH carrier <NUM> and <NUM>, respectively. In this case, when HARQ-ACK feedback for first or second PDSCH group is requested, it would be expected on the <NUM>st PUCCH carrier or on the <NUM>nd, respectively.

The method can be extended to more than two groups by extending the number of bits in the corresponding field in DCI to indicate more than one group and to DCI 1_2 by including the corresponding fields for Enhanced-Type <NUM> codebooks in DCI 1_2, similarly to DCI 1_1 in 3GPP Rel-<NUM>.

In a non-limiting embodiment, a DL SPS by configuration is associated to a PUCCH carrier in a PUCCH group.

In another non-limiting embodiment, a rule for association of a DL SPS configuration to a PUCCH carrier in a PUCCH group is used. In one or more embodiments, the wireless device <NUM> applies the rule for determining the association. Some examples of the rules are listed below:
Rule based on DL SPS configuration ID and PUCCH carriers:.

Rules based on SCS of DL SPS configuration. Some examples are provided below.

DL SPS configured on a bandwidth part (BWP) with a SCS larger or equal than the SCS of PUCCH carrier is associated to that PUCCH carrier, starting with PUCCH carrier with largest SCS.

In one non-limiting embodiment, multiple PUCCH carrier indication indices are provided by network node <NUM> to the wireless device <NUM> for PUCCH carrier switching for SPS HARQ-ACK. In one non-limiting embodiment, multiple PUCCH carrier indication for PUCCH carrier switching for SPS HARQ-ACK are provided in the activation DCI that is transmitted to the wireless device <NUM>. In one non-limiting embodiment, multiple PUCCH carrier indication indices are provided as a bitmap/sequence of PUCCH carrier indices, where the first value of the sequence corresponds to a PUCCH carrier indicator of SPS HARQ-ACK corresponding to the first SPS occasion after activation, and the second value of the sequence corresponds to a PUCCH carrier indicator of SPS HARQ-ACK corresponding to the second SPS occasion after activation, and so on. The values in the sequence are cycled through for further SPS occasions.

For example, if a sequence of PUCCH carrier indication indices {<NUM>, <NUM>, <NUM>} is provided to the wireless device <NUM>, then HARQ-ACK corresponding to the first, second, and third SPS PDSCHs after activation are transmitted on carrier index #<NUM>, #<NUM>, and #<NUM>, respectively, and HARQ-ACK corresponding to the fourth, fifth, and sixth SPS PDSCHs after activation are transmitted on carrier index #<NUM>, #<NUM>, and #<NUM>, and so on.

In one non-limiting embodiment, a wireless device <NUM> is configured by RRC multiple sequences for PUCCH carrier indices for SPS HARQ-ACK and is indicated in the activation DCI by an indicator indicating a specific sequence to use. In a special case, a sequence of PUCCH carrier indices has length <NUM>.

For example, a wireless device <NUM> is configured with <NUM> sequences of PUCCH carrier indication indices as shown in Table <NUM>.

If the wireless device <NUM> is indicated with '<NUM>' in the activation DCI, then HARQ-ACK corresponding to the first, second, and third SPS PDSCHs after activation are transmitted on carrier index #<NUM>, #<NUM>, and #<NUM>, respectively, and HARQ-ACK corresponding to the fourth, fifth, and sixth SPS PDSCHs after activation are transmitted on carrier index #<NUM>, #<NUM>, and #<NUM>, and so on.

If wireless device <NUM> is indicated with "<NUM>" in the activation DCI, then HARQ-ACK corresponding to all SPS PDSCH occasions are transmitted on carrier index #<NUM>.

In one version, the sequence to use is determined based on at least one or more of the following:.

In one non-limiting embodiment, SPS HARQ-ACK deferral is enabled or disabled per PUCCH carrier.

In one non-limiting embodiment, when SPS HARQ-ACK deferral is enabled at wireless device <NUM> for a first PUCCH carrier, SPS HARQ-ACK on the first PUCCH carrier which would be deferred to the next available UL on the carrier can be switched to/transmitted instead on a second (another) PUCCH carrier if one or more of the following conditions are met:.

there exists an UL slot or a special slot with valid symbols for UL transmission on the second PUCCH carrier, which starts earlier than the UL slot in which the SPS HARQ-ACK would be deferred to the first PUCCH carrier,.

the wireless device <NUM> is indicated with a PUCCH carrier indicator to use for the second PUCCH carrier for the SPS HARQ-ACK.

Point/item <NUM>. In one non-limiting embodiment, the PDSCH-to-HARQ_feedback timing indicator (K1) in the DCI scheduling PDSCH indicates the HARQ-ACK timing (K1) value with respect to the default PUCCH carrier, e.g., PCell of a PUCCH group.

Point/item <NUM>. In the above embodiment, if the indicated K1 value does not indicate a valid slot (e.g., a "D" slot in a TDD pattern is indicated for uplink transmission) for PUCCH transmission, the wireless device <NUM> can transmit PUCCH on another PUCCH carrier that has a valid slot for PUCCH transmission with respect to the indicated value instead. If there are multiple such carriers, called "valid carriers", the wireless device <NUM> can perform one of the following:.

Point/item <NUM>. In one non-limiting embodiment, the PDSCH-to-HARQ_feedback timing indicator (K1) in the DCI scheduling PDSCH indicates the HARQ-ACK timing (K1) value with respect to the PUCCH carrier to be used, e.g., another carrier other than the default PUCCH carrier.

Point/item <NUM>. In the above embodiments, the selection of PUCCH carrier based on the indication considers different SCS among DL and UL carriers.

Point/item <NUM>. In another non-limiting embodiment, a rule for associating a PDSCH to a PUCCH carrier in a PUCCH group is used such as by, for example, wireless device <NUM>. Some examples of the rules are listed below:
Rule based on the PDSCH cell index and PUCCH carrier index:.

Rules based on SCS of PDSCH and SCS of PUCCH carriers. Some examples are provided below.

DL cells configured with a SCS larger or equal than the SCS of PUCCH carrier is associated to that PUCCH carrier, starting with PUCCH carrier with largest SCS.

Point/item <NUM>. In another non-limiting embodiment, the impact of channel occupancy time (COT) (FBE, e.g., frame based equipment) is considered. The COT is channel occupancy time in NR-U (NR-unlicensed). If the COT is not grabbed (or cancelled/not allowed, e.g., due listen before talk (LBT) failure at COT initiation) whether in case of network node <NUM>-COT or wireless device <NUM>-COT, then wireless device <NUM> uses PUCCH (switch carrier), e.g., based on one or more of the above non-limiting rules/embodiments, conditioned, and/or it ignores the PUCCH resource which is part of non-grabbed (noninitiated) COT. An example of option depicted in point/item <NUM> above. It is assumed that wireless device <NUM> has currently both network node <NUM>-COT and wireless device <NUM>-COT configured. It is assumed that rule "PUCCH is transmitted on the carrier with the highest carrier index among the carriers" (2nd depicted bullet under point <NUM>) is used. It is assumed that wireless device <NUM> has PUCCH resources in non-overlapping network node <NUM>-COT and wireless device <NUM>-COT where in network node <NUM>-COT, PUCCH resources are part of higher carrier index, and in wireless device <NUM>-COT, the PUCCH is a part of relatively lower carrier index. If both network node <NUM>-COT and wireless device <NUM>-COT are grabbed, according to rule, wireless device <NUM> utilizes PUCCH resources from network node <NUM>-COT. If network node <NUM>-COT is grabbed/initiated but wireless device <NUM>-COT is not, then according to the rule, wireless device <NUM> transmits over PUCCH in network node <NUM>-COT, and if wireless device <NUM>-COT is grabbed/initiated but network node <NUM>-COT not, then according to the rule, wireless device <NUM> transmits over PUCCH in wireless device <NUM>-COT. In summary, whatever the one or more rules are described above for PUCCH/carrier switching, those carriers will be ignored which are part COTs which are not grabbed/initialized as wireless device <NUM> is not allowed to transmit in non-grabbed/non-initialized COTs. Note, the network node <NUM>-COT is initialized by the network node <NUM> and wireless device <NUM>-COT is initialized by the wireless device <NUM>, where both COT types and resources in the COTs are configured by network node <NUM>.

Point/item <NUM>. In one non-limiting embodiment, the associated PUCCH carriers (for switching purpose, e.g., for transmitting deferred HARQ. ACK) can have range of values (carrier indices) for a given SPS ID. For this an RRC table can be created with <NUM> columns, where first column denotes the row index, in <NUM>nd column, for each row index, it contains an SPS ID or group of SPS IDs, and in <NUM>rd column, it contains associated PUCCH carriers indices, as illustrated in Table <NUM>. In DCI, a <NUM> bit field can indicate a desired index which can activate the associated SPS IDs for indicated PUCCH carriers for HARQ-ACK transmission, e.g., in case deferral. Note, the rule for selecting PUCCH carrier, e.g., for deferral purpose for a given SPS ID can be based on any non-limited embodiment described herein over the set of indicated PUCCH carrier indices referred by DCI containing row index.

When dynamic carrier switching is applied for HARQ-ACK such that the HARQ-ACK is to be transmitted on a dynamically-selected carrier c, the "TPC command for scheduled PUCCH" field in the scheduling DCI format is applied to the PUCCH on carrier c. Here the scheduling DCI refers to a DL DCI format that schedules a PDSCH, which is to be acknowledged by the HARQ-ACK. The DL DCI format include at least DCI format 1_1 and 1_2.

For 3GPP Rel-<NUM>, it has been considered that simultaneous PUCCH/PUSCH transmissions on different cells is supported at least for inter-band carrier aggregation (CA). 3GPP has left further study whether this simultaneous PUCCH/PUSCH will to be supported for intra-band CA.

Per wireless device <NUM> with the capability of inter-band CA, simultaneous PUCCH/PUSCH transmission of different PHY priorities over different cells can be RRC configured within the same PUCCH group.

For wireless device <NUM> with the capability of simultaneous PUCCH/PUSCH transmission within the same PUCCH group, then the HARQ-ACK bits can be assigned to be carried by the PUSCH-only carrier(s) also, i.e., the HARQ-ACK bits are not restricted to the cell for PUCCH within the PUCCH group.

For the primary PUCCH group, the PUSCH-only carriers refer to the primary cell (i.e., PCell) in the primary PUCCH group. The PUSCH-only carrier refers to other cells in the primary PUCCH group.

For the secondary PUCCH group, the cell for PUCCH refers to the PUCCH-SCell of the secondary PUCCH group. The PUSCH-only carrier refers to other cells in the secondary PUCCH group.

When the HARQ-ACK codebook is scheduled on a PUSCH only cell c<NUM> at slot n:.

In one or more embodiments, due to the simultaneous PUCCH/PUSCH transmission within the same PUCCH group, a PUCCH transmission on a cell capable of PUCCH (i.e., PCell or PUCCH-SCell) is not to be multiplexed with a PUSCH on the PUSCH-only cell in the same PUCCH group, even if the PUCCH and PUSCH overlap in time.

The assignment of HARQ-ACK bits on a PUSCH-only cell can be via either dynamic or semi-static PUCCH carrier switching. On the other hand, dynamic PUCCH carrier switching may be used so that the error case can be avoided.

The HARQ-ACK codebook for the PUSCH-only cell can be of any type, e.g., type <NUM> HARQ-ACK CB, type <NUM> HARQ-ACK CB, or type <NUM> HARQ-ACK CB (i.e., one shot HARQ-ACK feedback). The type can be configured specifically for this cell c<NUM>, and it may be independent of, and different from the HARQ-ACK codebook type for the PUCCH group that cell c<NUM> belongs to.

Therefore, one or more embodiments described herein enable supports for Type-<NUM> HARQ-ACK codebook and SPS HARQ-ACK deferral when PUCCH carrier switching is allowed. One or more embodiments described herein also provide alternative methods to enable PUCCH carrier switching based on certain rules and configurations.

With the full support of PUCCH carrier switching, it may be useful, e.g., for URLLC, to reduce the overall DL transmission latency which involves HARQ retransmission.

Computer program code for carrying out operations of the concepts described herein may be written in an object oriented programming language such as Python, Java® or C++.

Claim 1:
A method implemented by a wireless device (<NUM>) configured to communicate with a network node (<NUM>), the method comprising:
receiving (S146) a first indication of a first physical uplink control channel, PUCCH, carrier for dynamic PUCCH carrier switching; and
performing (S148) dynamic PUCCH carrier switching from a second PUCCH carrier to the first PUCCH carrier based at least on the first indication;
wherein the method further comprises receiving a second indication that a semi-persistent scheduling, SPS, hybrid automatic repeat request-acknowledgement, HARQ-ACK, deferral is enabled for the second PUCCH carrier, the dynamic PUCCH carrier switching being performed instead of the SPS HARQ-ACK deferral.