Acknowledgements of received transmissions

Abstract

The UE receives (S104) a plurality of control information messages scheduling respective transmissions to the UE. The UE reports (S106) acknowledgements of reception of the scheduled transmissions. The control information messages comprise feedback report identifiers indicating which of the scheduled transmissions to be acknowledged in the same report. The reporting is performed based on the feedback report identifiers.

Description

[0001] ACKNOWLEDGEMENTS OF RECEIVED TRANSMISSIONS

[0002] TECHNICAL FIELD

[0003] The present disclosure relates to wireless communications, and in particular, to acknowledgements of received transmissions..

[0004] BACKGROUND

[0005] The Third Generation Partnership Project (3GPP) has developed and is developing standards for Fourth Generation (4G) (also referred to as Long Term Evolution (LTE)) and Fifth Generation (5G) (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 user equipments (UE), as well as communication between network nodes and between UEs. The 3GPP is also developing standards for Sixth Generation (6G) wireless communication networks.

[0006] Downlink and uplink data transmission in 5G

[0007] Downlink data transmission is transmitted on the physical downlink shared channel (PDSCH). Associated control information informs the UE about the timefrequency resources used for the data transmission as well as other parameters necessary to process the downlink transmission. Hybrid automatic repeat request (HARQ or Hybrid- ARQ) is supported in the downlink. Shortly after receiving the downlink data transmission the UE responds with a positive or negative acknowledgement indicating whether the data was correctly received or not.

[0008] Uplink data transmission is transmitted on the physical uplink shared channel (PUSCH). Similarly to the downlink case, the associated control information informs the UE about the time-frequency resources to use and other transmission parameters necessary. If the uplink data are not correctly received, the network node can schedule a retransmission.

[0009] Downlink control information in 5G

[0010] Downlink control information (DCI) includes downlink scheduling assignments, including information required for the device to be able to properly receive, demodulate, and decode downlink data transmissions, and uplink scheduling grants informing the device about the resources and transport format to use for uplink data transmission. In addition, the downlink control signaling can also be used for special purposes such as conveying information about the symbols used for uplink and downlink in a set of slots, preemption indication, and power control.

[0011] Apart from indicating the time-frequency resources used for downlink data transmission, the DCI may also include:

[0012] • Hybrid-ARQ related information o Hybrid ARQ process number, informing the device about the hybrid- ARQ process to use for soft combining. o Downlink assignment index (DAI), only present in the case of a dynamic hybrid- ARQ codebook is configured. o HARQ feedback timing, providing information on when the hybrid- ARQ acknowledgment should be transmitted in the uplink relative to the reception of the PDSCH.

[0013] • Physical uplink control channel (PUCCH)-related information o PUCCH resource indicator, used to select the PUCCH resource from a set of configured resources.

[0014] Only some fields related to DCI have been listed above.

[0015] Uplink control information (UCI) in 5G

[0016] In 5GNR, there is a need for uplink layer 1 / layer 2 (L1 / L2) control signaling to support data transmission on downlink and uplink transport channels. Uplink L1 / L2 control signaling in 5G NR includes:

[0017] • Hybrid-ARQ acknowledgments for downlink transport blocks received by the UE;

[0018] • Channel-state information (CSI) related to the downlink channel conditions, used to assist downlink scheduling, including multi-antenna and beamforming schemes; and

[0019] • Scheduling requests, indicating that a device needs uplink resources for data transmission.

[0020] The physical uplink control channel (PUCCH) is the basis for the transmission of uplink control. In principle, the uplink control information (UCI) could be transmitted on the PUCCH regardless of whether the device is transmitting data on the PUSCH simultaneously. However, especially if the uplink resources for the PUSCH and the PUCCH are on the same carrier (or, to be more precise, use the same power amplifier) but widely separated in the frequency domain, the UE may need a relatively large power backoff to fulfill the spectral emission requirements with a corresponding impact on the uplink coverage. Hence, NR supports UCI on PUSCH as a way of handling simultaneous transmission of data and control. If the UE is transmitting on the PUSCH, the UCI is multiplexed with data on the granted resources instead of being transmitted on the PUCCH.

[0021] In the case of carrier aggregation, the uplink control information is transmitted on the primary cell as a baseline. This is motivated by the need to support asymmetric carrier aggregation where the number of downlink carriers supported by a UE is unrelated to the number of uplink carriers.

[0022] UCI on PUCCH

[0023] Uplink control information can be transmitted on PUCCH using several different formats.

[0024] Two of the formats, 0 and 2, may be referred to as short PUCCH formats, as they occupy at most two Orthogonal Frequency Division Multiplexing (OFDM) symbols. In some cases, the last one or two OFDM symbols in a slot are used for PUCCH transmission, for example, to transmit a hybrid-ARQ acknowledgment of the downlink data transmission. The short PUCCH formats include:

[0025] • PUCCH format 0, capable of transmitting at most two bits and spanning one or two OFDM symbols. This format can, for example, be used to transmit a hybrid- ARQ acknowledgment of a downlink data transmission, or to issue a scheduling request.

[0026] • PUCCH format 2, capable of transmitting more than two bits and spanning one or two OFDM symbols. This format can, for example, be used for CSI reports or for multi-bit hybrid-ARQ acknowledgments in the case of carrier aggregation or percode block group (CBG) retransmission.

[0027] Three of the formats, 1, 3, and 4, are sometimes referred to as long PUCCH formats as they occupy from 4 to 14 OFDM symbols. The reason for having a longer time duration than the previous two formats is coverage. If a duration of one or two OFDM symbols does not provide sufficient energy for reliable reception, a longer time duration may be necessary and one of the long PUCCH formats can be used. The long PUCCH formats include:

[0028] • PUCCH format 1, capable of transmitting at most two bits.

[0029] • PUCCH formats 3 and 4, both capable of transmitting more than two bits but differing in the multiplexing capacity, that is, how many UEs can use the same time-frequency resource simultaneously. Transmission of PUCCH requires time-frequency resources. In 5GNR, a flexible scheme is used, which is necessary given the very flexible framework with a wide range of service requirements in terms of latency and spectral efficiency, support of no predefined uplink-downlink allocation in Time Division Duplex (TDD), different devices supporting aggregation of different number of carriers, and different antenna schemes requiring different amounts of feedback, for example. One aspect of this scheme is the notion of PUCCH resource sets. A PUCCH resource set contains one or more PUCCH resource configurations where each resource configuration contains the PUCCH format to use and all the parameters necessary for that format. The first PUCCH resource set can contain up to 32 PUCCH resources while the remaining sets may contain up to eight resources each. Up to four PUCCH resource sets can be configured, each of them corresponding to a certain range of the number of UCI bits to transmit. PUCCH resource set 0 can handle UCI payloads up to two bits and hence only contain PUCCH formats 0 and 1, while the remaining PUCCH resource sets may contain any PUCCH format except format 0 and 1.

[0030] When the UE is about to transmit UCI, the UCI payload determines the PUCCH resource set and the PUCCH resource indicator in the DCI determines the PUCCH resource configuration within the PUCCH resource set (see FIG. 1). Thus, the scheduler has control of where the uplink control information is transmitted. For the first resource set, which may contain up to 32 resources, there can be more resources than what is possible to indicate with a three-bit PUCCH resource indicator. If this is the case, the index of the first CCE of the Physical Downlink Control Channel (PDCCH) scheduling the uplink is used together with the PUCCH resource indicator to determine the PUCCH resource within the set. For periodic CSI reports and scheduling request opportunities, which both are semi-statically configured, the PUCCH resources are provided as part of the CSI or scheduling request (SR) configuration.

[0031] UCI on PUSCH

[0032] If the UE is transmitting data on PUSCH - that is, has a valid scheduling grant - the UCI is “rerouted” from the PUCCH to the PUSCH. Only hybrid-ARQ acknowledgments and CSI reports are rerouted to the PUSCH. There is no need to request a scheduling grant when the device is already scheduled.

[0033] In principle, the network node knows when to expect a hybrid-ARQ acknowledgment from the device and can therefore perform the appropriate demultiplexing of the acknowledgment and the data part. However, there is a certain probability that the UE has missed the scheduling assignment on the downlink control channel. In this case the network node would expect a hybrid- ARQ acknowledgment while the UE will not transmit one. If the rate-matching pattern depends on whether an acknowledgment is transmitted or not, all the coded bits transmitted in the data part could be affected by a missed assignment and are likely to cause the uplink shared channel (UL- SCH) decoding to fail.

[0034] One possibility to avoid this error is to puncture hybrid- ARQ acknowledgments onto the coded UL-SCH stream in which case the non-punctured bits are unaffected by the presence / absence of hybrid-ARQ acknowledgments. This is also the solution adopted in LTE. However, given the potentially large number of acknowledgment bits due to, for example, carrier aggregation or the use of codeblock group retransmissions, puncturing is less suitable as a general solution. Instead, NR has adopted a scheme where up to two hybrid-ARQ acknowledgment bits are punctured, while for a larger number of bits, rate matching of the uplink data is used. To avoid the aforementioned error cases, the uplink DAI field in the DCI indicates the amount of resources reserved for uplink hybrid ARQ. Thus, regardless of whether the UE missed any previous scheduling assignments or not, the amount of resources to use for the uplink hybrid-ARQ feedback is known.

[0035] UCI on L2

[0036] HARQ feedback (and other uplink control information) may be multiplexed into the data stream before channel coding. In this scheme, the UE determines when to feedback HARQ feedback formatted as a Medium Access Control (MAC) Control Element (CE). MAC CE is a flexible data structure which can handle varying reporting sizes, which makes it suitable for HARQ feedback which - due to dynamic scheduling - typically is variable in size.

[0037] This scheme decouples downlink (DL) and uplink (UL) scheduler which is helpful from an implementation perspective (The size of HARQ feedback depends on DL scheduling decisions, if the network node would need to exactly match the allocated UL resources to the HARQ feedback size this would tightly link DL and UL scheduler). With UCI on layer 2 (L2), the network node allocates a certain amount of UL resources for data and uplink control information, and due to size-flexibility of MAC CEs the network node does not need to bother about the exact size of uplink control information.

[0038] Carrier aggregation

[0039] Carrier aggregation is supported in 5G NR, that is, data transmissions to / from a UE may use multiple carriers, e.g., to obtain very high data rates. A UE capable of carrier aggregation may receive or transmit simultaneously on multiple component carriers while a UE not capable of carrier aggregation can access one of the component carriers only. Thus, the physical-layer description applies to each component carrier separately in the case of carrier aggregation.

[0040] In some specifications (e.g., 3GPP specifications), carrier aggregation is described using the term cell, that is, a carrier-aggregation-capable UE is able to receive and transmit from / to multiple cells. One of these cells is referred to as the primary cell (PCell). This is the cell which the UE initially finds and connects to, after which one or more secondary cells (SCells) can be configured once the UE is in connected mode. The secondary cells can be activated or deactivated to meet the variations in the traffic pattern. Different UEs may have different cells as their primary cell — that is, the configuration of the primary cell is device-specific. Furthermore, the number of carriers (or cells) does not have to be the same in uplink and downlink. In fact, a typical case is to have more carriers aggregated in the downlink than in the uplink. There are several reasons for this. There is typically more traffic in the downlink than in the uplink. Furthermore, the radio frequency (RF) complexity from multiple simultaneously active uplink carriers is typically larger than the corresponding complexity in the downlink.

[0041] Scheduling grants and scheduling assignments, or in general terms downlink control information, is as a baseline transmitted separately per carrier scheduled, that is, there is one PDCCH for each scheduling grant or assignment sent to the UE.

[0042] Control information for scheduling purposes can be transmitted on either the same cell as the corresponding data, known as self-scheduling, or on a different cell than the corresponding data, known as cross-carrier scheduling. There is also a need for uplink control signaling, for example, hybrid- ARQ acknowledgements to inform the network node about the success or failure of downlink data reception. As a baseline, all the feedback is transmitted on the PCell, motivated by the need to support asymmetric carrier aggregation with the number of downlink carriers supported by a UE unrelated to the number of uplink carriers. For a large number of downlink component carriers, a single uplink carrier may thus carry a large number of acknowledgements.

[0043] Hybrid-ARQ (HARQ)

[0044] Hybrid-ARQ is one of the retransmission mechanisms in 5GNR. The basis for the NR hybrid- ARQ mechanism is a structure with multiple stop-and-wait protocols, each operating on a single transport block on one carrier. In a stop-and-wait protocol, the transmitter stops and waits for an acknowledgement after each transmitted transport block. This is a low complexity scheme; the only feedback required is a single bit indicating positive or negative acknowledgement of the transport block. However, since the transmitter stops after each transmission, the throughput is also low. Therefore, multiple stop-and-wait processes operating in parallel are used such that, while waiting for acknowledgement from one process, the transmitter can transmit data to another hybrid- ARQ process. This structure, multiple hybrid-ARQ processes operating in parallel to form one hybrid-ARQ entity, combines the low complexity of a stop-and-wait protocol with the possibility of continuous data transmission.

[0045] Acknowledgement, positive or negative, of a received transport block is fed back from the UE to the network node. The UE needs to know when to transmit the acknowledgement in the uplink in response to a downlink reception. The hybrid-ARQ timing field in the downlink DCI is used to control the transmission timing of the acknowledgement in the uplink. This three-bit field is used as an index into a Radio Resource Control (RRC) configured table providing information on when the hybrid-ARQ acknowledgement should be transmitted relative to the reception of the PDSCH (see FIG. 2). In this particular example, three slots are scheduled in the downlink before an acknowledgement is transmitted in the uplink. In each downlink assignment, different acknowledgement timing indices have been used, which in combination with the RRC- configured table result in all three slots being acknowledged at the same time (multiplexing of these acknowledgments in the same slot is discussed below).

[0046] For proper transmission of the acknowledgement, it is not sufficient for the device to know when to transmit, which is obtained from the timing field discussed, but also where in the resource domain. This is handled through the PUCCH resource indicator, which is a three-bit index selecting one of eight RRC -configured resources as discussed above.

[0047] Multiple transport blocks may need to be indicated at the same time, for example, in TDD where multiple downlink slots are followed by a single uplink slot, or in case of carrier aggregation where transmissions on multiple downlink carriers need to be acknowledged on a single uplink carrier. In these cases, a multi-bit report formed according to a HARQ codebook is used. Different types of codebooks exists: type 1 (semistatic), type 2 (dynamic), or type 3 (used for unlicensed spectrum).

[0048] Semi-static codebook (type 1)

[0049] The semi-static codebook can be viewed as a matrix consisting of a time-domain dimension and a component-carrier dimension, both of which are semi-statically configured. The size in the time domain is given by the maximum and minimum hybrid- ARQ acknowledgement timings configured, and the size in the carrier domain is given by the number of simultaneous transport blocks across all component carriers. An example is provided in FIG. 3, where the acknowledgment timings are one, two, three, and four, respectively, and three carriers, one with two transport blocks, one with one transport block, and one with four CBGs, are configured. Since the codebook size is fixed, the number of bits to transmit in a hybrid-ARQ report is known (4 -7=28 bits in the example in FIG. 3) and the appropriate format for the uplink control signaling can be selected. Each entry in the matrix represents the decoding outcome, positive or negative acknowledgment, of the corresponding transmission. Not all transmission opportunities possible with the codebook are used in this example and for entries in the matrix without a corresponding transmission, a negative acknowledgment is transmitted. This provides robustness; in the case of missed downlink assignment a negative acknowledgment is provided to the network node, which can retransmit the missing transport block (or CBG).

[0050] Dynamic codebook (type 2)

[0051] With a dynamic codebook, only the acknowledgement information for the scheduled carriers is included in the report, instead of all carriers, scheduled or not, as is the case with a semi-static codebook. The description here uses the term ‘carrier’ but the same principle is equally applicable to per-CBG retransmission or multiple transport blocks in case of Multiple-Input Multiple-Output (MIMO). Hence, the size of the codebook (the matrix in FIG. 3) is dynamically varying as a function of the number of scheduled carriers. In essence, only the bold entries in the example in FIG. 3 would be included in the hybrid-ARQ report and the non-bold entries with a white background (which correspond to non-scheduled carriers) would be omitted. This reduces the size of the acknowledgement message.

[0052] A dynamic codebook would be straightforward if there were no errors in the downlink control signaling. However, in presence of an error in the downlink control signaling, the UE and network node may have a different understanding on the number of scheduled carriers which would lead to an incorrect codebook size and possibly corrupt the feedback report for all carriers, and not only for the ones for which the downlink controls signaling was missed. Assume, as an example, that the device was scheduled for downlink transmission in two subsequent slots but missed the PDCCH and hence scheduling assignment for the first slot. In response, the UE will transmit an acknowledgement for the second slot only, while the network node tries to receive acknowledgments for two slots, leading to a mismatch. To handle these error cases, NR uses the downlink assignment index (DAI) included in the DCI containing the downlink assignment. The DAI field is further split into two parts, a counter DAI (cDAI) and, in the case of carrier aggregation, a total DAI (tDAI). The counter DAI included in the DCI indicates the number of scheduled downlink transmissions up to the point the DCI was received in a carrier first, time second manner. The total DAI included in the DCI indicates the total number of downlink transmissions across all carriers up to this point in time, that is, the highest cDAI at the current point in time (see FIG. 4 for an example). The counter DAI and total DAI are represented with decimal numbers with no limitation; in practice two bits are used for each and the numbering will wrap around, that is, what is signaled is the numbers in the figure modulo four. As seen in this example, the dynamic codebook needs to account for 17 acknowledgments (numbered 0 to 16). This can be compared with the semi-static codebook which would require 28 entries regardless of the number of transmissions.

[0053] Furthermore, in this example, one transmission on component carrier five is lost. Without the DAI mechanism, this would result in misaligned codebooks between the UE and the network node. However, as long as the UE receives at least one component carrier, it knows the value of the total DAI and hence the size of the codebook at this point in time. Furthermore, by checking the values received for the counter DAI, it can conclude which component carrier was missed and that a negative acknowledgement should be assumed in the codebook for this position.

[0054] As part of the DCI that schedules a downlink transmission, a slot and PUCCH resource is indicated which should be used for the HARQ feedback. The above description describes how the HARQ codebook is constructed for those PDSCH acknowledged in the same PUCCH. The UE knows all PDSCH that it should acknowledge (assuming it can reconstruct all potentially missed DL assignments using the DAI mechanism outlined above) in the same PUCCH, backtracks the scheduling PDCCH, and sorts the HARQ feedback according to a carrier first, time second manner of the scheduling PDCCH. Scheduling

[0055] 3GPP NR is a scheduled system, implying that the scheduler determines when and to which UEs the time, frequency, and spatial resources should be assigned and what transmission parameters, including data rate, to use. Scheduling can be either dynamic or semi-static. Dynamic scheduling is the basic mode-of-operation where the scheduler for each time interval, for example, a slot, determines which UEs are to transmit and receive. Since scheduling decisions are taken frequently, it is possible to follow rapid variations in the traffic demand and radio-channel quality, thereby efficiently exploiting the available resources. Semi-static scheduling implies that the transmission parameters are provided to the UEs in advance and not on a dynamic basis.

[0056] The scheduler strategy and how to implement it is not standardized but left for the vendor to decide upon - only the control signaling mechanism between the network node and the UE is specified in the standard.

[0057] One possibility is to implement one single, monolithic scheduler controlling all uplink and downlink transmissions on all carriers. However, this may not always be possible, especially for large network nodes handling a large number of UEs. Implementations with a separate downlink scheduler for each carrier, as well as a separate uplink scheduler for each uplink carrier, is possible. In this case, the different schedulers need to interact to some extent when taking the scheduling decisions. For example, the different downlink schedulers need to interact when deciding on the number of carriers to use for downlink data transmission. In particular, they need to agree on the DAI field in the DCI in order to form the HARQ codebook. This interaction is time-critical as the data transmission and the associated control signaling typically are transmitted in the same slot.

[0058] However, transmission of HARQ-related feedback in the uplink using the NR scheme requires very tight interaction both between the downlink schedulers (e.g., when forming the DAI) and between the downlink and uplink schedulers (e.g., uplink resources used for HARQ feedback are controlled by the downlink scheduler and not the uplink scheduler). This complicates the scheduling implementation.

[0059] The UCI on L2 scheme described above decouples DL and UL scheduler. A drawback of putting HARQ feedback on L2 is the report size: in its simplest form, each HARQ feedback bit is accompanied with the corresponding HARQ process number (4 bit) and carrier indicator field (depends on number of activated / configured carriers). This leads to a report size many times larger than the dynamic HARQ codebook.

[0060] SUMMARY

[0061] A first aspect provides embodiment of a method implemented in a user equipment (UE). The UE is configured to communicate with a network node. The method comprises receiving a plurality of control information messages scheduling respective transmissions to the UE. The method comprises reporting acknowledgements of reception of the scheduled transmissions. The control information messages comprise feedback report identifiers indicating which of the scheduled transmissions to be acknowledged in the same report. The reporting is performed based on the feedback report identifiers.

[0062] Corresponding embodiments of a UE are also provided.

[0063] A second aspect provides embodiments of a method implemented in a network node. The network node is configured to communicate with a UE. The method comprises transmitting a plurality of control information messages scheduling respective transmissions to the UE. The method comprises receiving, from the UE, reporting of acknowledgements of reception of the scheduled transmissions. Wherein the control information messages comprise feedback report identifiers indicating which of the scheduled transmissions to be acknowledged in the same report. The reporting is based on the feedback report identifiers.

[0064] Corresponding embodiments of a network node are also provided.

[0065] BRIEF DESCRIPTION OF THE DRAWINGS

[0066] A more complete understanding of the present embodiments, and the attendant advantages and features thereof, will be more readily understood by reference to the following detailed description when considered in conjunction with the accompanying drawings wherein:

[0067] FIG. 1 is a diagram of an example of PUCCH resources;

[0068] FIG. 2 is a diagram of an example of acknowledgement timing;

[0069] FIG. 3 is a diagram of an example of semi-static HARQ codebook;

[0070] FIG. 4 is a diagram of an example of dynamic HARQ acknowledgement codebook;

[0071] FIG. 5 is a schematic diagram of an example network architecture illustrating a communication system according to principles disclosed herein;

[0072] FIG. 6 is a block diagram of a network node in communication with a user equipment over a wireless connection according to some embodiments of the present disclosure;

[0073] FIG. 7 is a flowchart of an example process in a network node according to some embodiments of the present disclosure;

[0074] FIG. 8 is a flowchart of an example process in a user equipment according to some embodiments of the present disclosure; and

[0075] FIG. 9 is a block diagram illustrating a virtualization environment in which functions implemented by some embodiments may be virtualized. DETAILED DESCRIPTION

[0076] Before describing in detail exemplary embodiments, it is noted that the embodiments reside primarily in combinations of apparatus components and processing steps related to acknowledgements of received transmissions.. 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.

[0077] As used herein, relational terms, such as “first” and “second,” “top” and “bottom,” and the like, may be used solely to distinguish one entity or element from another entity or element without necessarily requiring or implying any physical or logical relationship or order between such entities or elements. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the concepts described herein. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises,” “comprising,” “includes” and / or “including” when used herein, specify the presence of stated features, integers, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof.

[0078] In embodiments described herein, the joining term, “in communication with” and the like, may be used to indicate electrical or data communication, which may be accomplished by physical contact, induction, electromagnetic radiation, radio signaling, infrared signaling or optical signaling, for example. One having ordinary skill in the art will appreciate that multiple components may interoperate and modifications and variations are possible of achieving the electrical and data communication.

[0079] In some embodiments described herein, the term “coupled,” “connected,” and the like, may be used herein to indicate a connection, although not necessarily directly, and may include wired and / or wireless connections.

[0080] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the concepts described herein. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises,” “comprising,” “includes” and / or “including” when used herein, specify the presence of stated features, integers, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof.

[0081] 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, multistandard radio (MSR) radio node such as MSR BS, multi-cell / multicast coordination entity (MCE), 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 user equipment (UE) such as a wireless device (WD) or a radio network node.

[0082] In some embodiments, the non-limiting terms wireless device (WD) or a user equipment (UE) are used interchangeably. The UE herein can be any type of user equipment capable of communicating with a network node or another UE over radio signals, such as a wireless device (WD). The UE may also be a radio communication device, target device, device to device (D2D) UE, machine type UE or UE capable of machine to machine communication (M2M), low-cost and / or low-complexity UE, a sensor equipped with UE, Tablet, mobile terminals, smart phone, laptop embedded equipped (LEE), laptop mounted equipment (LME), USB dongles, Customer Premises Equipment (CPE), an Internet of Things (loT) device, or a Narrowband loT (NB-IOT) device etc.

[0083] Also, in some embodiments the generic term “radio network node” is used. It can be any kind of a radio network node which may comprise any of base station, radio base station, base transceiver station, base station controller, network controller, RNC, evolved Node B (eNB), Node B, gNB, Multi-cell / multicast Coordination Entity (MCE), relay node, access point, radio access point, Remote Radio Unit (RRU) Remote Radio Head (RRH). Note that although terminology from one particular wireless system, such as, for example, 3GPP LTE and / or New Radio (NR) and / or 6G, may be used in this disclosure, this should not be seen as limiting the scope of the disclosure to only the aforementioned system. It is contemplated that other 3GPP systems may make use of the concepts and arrangements disclosed herein. For example, a disclosure relating to NR may also be implementable in a 6G system and / or an LTE system, a disclosure relating to 6G may also be implementable in a NR and / or LTE system, and a disclosure relating to LTE may also be implementable in a NR and / or 6G system. Other wireless systems, including without limitation Wide Band Code Division Multiple Access (WCDMA), Worldwide Interoperability for Microwave Access (WiMax), Ultra Mobile Broadband (UMB) and Global System for Mobile Communications (GSM), may also benefit from exploiting the ideas covered within this disclosure.

[0084] Note further, that functions described herein as being performed by a user equipment or a network node may be distributed over a plurality of user equipments and / or network nodes. In other words, it is contemplated that the functions of the network node and user equipment described herein are not limited to performance by a single physical device and, in fact, can be distributed among several physical devices.

[0085] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. It will be further understood that terms used herein should be interpreted as having a meaning that is consistent with their meaning in the context of this specification and the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

[0086] Some embodiments are directed to acknowledgements of received transmissions. Referring again to the drawing figures, in which like elements are referred to by like reference numerals, there is shown in FIG. 5 a schematic diagram of a communication system 10, according to an embodiment, such as a 3 GPP-type cellular network that may support standards such as LTE and / or NR (5G) and / or 6G, which comprises an access network 12, such as a radio access network, and a core network 14. The access network 12 comprises a plurality of network nodes 16a, 16b, 16c (referred to collectively as network nodes 16), 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 18). Each network node 16a, 16b, 16c is connectable to the core network 14 over a wired or wireless connection 20. A first user equipment (UE) 22a located in coverage area 18a is configured to wirelessly connect to, or be paged by, the corresponding network node 16a. A second UE 22b in coverage area 18b is wirelessly connectable to the corresponding network node 16b. While a plurality of UEs 22a, 22b (collectively referred to as user equipments 22) are illustrated in this example, the disclosed embodiments are equally applicable to a situation where a sole UE is in the coverage area or where a sole UE is connecting to the corresponding network node 16. Note that although only two UEs 22 and three network nodes 16 are shown for convenience, the communication system may include many more UEs 22 and network nodes 16.

[0087] Also, it is contemplated that a UE 22 can be in simultaneous communication and / or configured to separately communicate with more than one network node 16 and more than one type of network node 16. For example, a UE 22 can have dual connectivity with a network node 16 that supports LTE and the same or a different network node 16 that supports NR. As an example, UE 22 can be in communication with an eNB for LTE / E-UTRAN and a gNB for NR / NG-RAN.

[0088] A network node 16 (eNB or gNB) is configured to include a control information unit 24 which is configured to perform one or more network node 16 functions as described herein. A UE 22 is configured to include a reporting unit 26 which is configured to perform one or more UE 22 functions as described herein.

[0089] Example implementations, in accordance with an embodiment, of the UE 22 and network node 16 discussed in the preceding paragraphs will now be described with reference to FIG. 6.

[0090] The communication system 10 includes a network node 16 provided in a communication system 10 and including hardware 28 enabling it to communicate with the UE 22. The hardware 28 may include a radio interface 30 for setting up and maintaining at least a wireless connection 32 with a UE 22 located in a coverage area 18 served by the network node 16. The radio interface 30 may be formed as or may include, for example, one or more RF transmitters, one or more RF receivers, and / or one or more RF transceivers. The radio interface 30 includes an array of antennas 34 to radiate and receive signal(s) carrying electromagnetic waves.

[0091] In the embodiment shown, the hardware 28 of the network node 16 further includes processing circuitry 36. The processing circuitry 36 may include a processor 38 and a memory 40. In particular, in addition to or instead of a processor, such as a central processing unit, and memory, the processing circuitry 36 may comprise integrated circuitry for processing and / or control, e.g., one or more processors and / or processor cores and / or FPGAs (Field Programmable Gate Array) and / or ASICs (Application Specific Integrated Circuitry) adapted to execute instructions. The processor 38 may be configured to access (e.g., write to and / or read from) the memory 40, which may comprise any kind of volatile and / or nonvolatile memory, e.g., cache and / or buffer memory and / or RAM (Random Access Memory) and / or ROM (Read-Only Memory) and / or optical memory and / or EPROM (Erasable Programmable Read-Only Memory).

[0092] Thus, the network node 16 further has software 42 stored internally in, for example, memory 40, or stored in external memory (e.g., database, storage array, network storage device, etc.) accessible by the network node 16 via an external connection. The software 42 may be executable by the processing circuitry 36. The processing circuitry 36 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 16. Processor 38 corresponds to one or more processors 38 for performing network node 16 functions described herein. The memory 40 is configured to store data, programmatic software code and / or other information described herein. In some embodiments, the software 42 may include instructions that, when executed by the processor 38 and / or processing circuitry 36, causes the processor 38 and / or processing circuitry 36 to perform the processes described herein with respect to network node 16. For example, processing circuitry 36 of the network node 16 may include control information unit 24 which is configured to perform one or more network node 16 functions as described herein.

[0093] The communication system 10 further includes the UE 22 already referred to. The UE 22 may have hardware 44 that may include a radio interface 46 configured to set up and maintain a wireless connection 32 with a network node 16 serving a coverage area 18 in which the UE 22 is currently located. The radio interface 46 may be formed as or may include, for example, one or more RF transmitters, one or more RF receivers, and / or one or more RF transceivers. The radio interface 46 includes an array of antennas 48 to radiate and receive signal(s) carrying electromagnetic waves.

[0094] The hardware 44 of the UE 22 further includes processing circuitry 50. The processing circuitry 50 may include a processor 52 and memory 54. In particular, in addition to or instead of a processor, such as a central processing unit, and memory, the processing circuitry 50 may comprise integrated circuitry for processing and / or control, e.g., one or more processors and / or processor cores and / or FPGAs (Field Programmable Gate Array) and / or ASICs (Application Specific Integrated Circuitry) adapted to execute instructions. The processor 52 may be configured to access (e.g., write to and / or read from) memory 54, which may comprise any kind of volatile and / or nonvolatile memory, e.g., cache and / or buffer memory and / or RAM (Random Access Memory) and / or ROM (Read-Only Memory) and / or optical memory and / or EPROM (Erasable Programmable Read-Only Memory).

[0095] Thus, the UE 22 may further comprise software 56, which is stored in, for example, memory 54 at the UE 22, or stored in external memory (e.g., database, storage array, network storage device, etc.) accessible by the UE 22. The software 56 may be executable by the processing circuitry 50. The software 56 may include a client application 58. The client application 58 may be operable to provide a service to a human or non-human user via the UE 22.

[0096] The processing circuitry 50 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 UE 22. The processor 52 corresponds to one or more processors 52 for performing UE 22 functions described herein. The UE 22 includes memory 54 that is configured to store data, programmatic software code and / or other information described herein. In some embodiments, the software 56 and / or the client application 58 may include instructions that, when executed by the processor 52 and / or processing circuitry 50, causes the processor 52 and / or processing circuitry 50 to perform the processes described herein with respect to UE 22. For example, the processing circuitry 50 of the user equipment 22 may include reporting unit 26 which is configured to perform one or more UE 22 functions as described herein.

[0097] In some embodiments, the inner workings of the network node 16 and UE 22 may be as shown in FIG. 6 and independently, the surrounding network topology may be that of FIG. 5.

[0098] The wireless connection 32 between the UE 22 and the network node 16 is in accordance with the teachings of the embodiments described throughout this disclosure. More precisely, the teachings of some of these embodiments may improve the data rate, latency, and / or power consumption and thereby provide benefits such as reduced user waiting time, relaxed restriction on file size, better responsiveness, extended battery lifetime, etc. In some embodiments, a measurement procedure may be provided for the purpose of monitoring data rate, latency and other factors on which the one or more embodiments improve. Although FIGS. 5 and 6 show various “units” such as control information unit 24 and reporting unit 26 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.

[0099] For example, in some embodiments, the telecommunication system 10 includes one or more Open-RAN (ORAN) network nodes 16. An ORAN network node 16 is anode in the telecommunication system 10 that supports an ORAN specification (e.g., a specification published by the O-RAN Alliance, or any similar organization) and may operate alone or together with other nodes to implement one or more functionalities of any node in the telecommunication system 10, including one or more network nodes 16 in the access network 12 and / or core network nodes core network 14.

[0100] Examples of an ORAN network node 16 include an open radio unit (O-RU), an open distributed unit (O-DU), an open central unit (O-CU), including an O-CU control plane (O-CU-CP) or an O-CU user plane (O-CU-UP), a RAN intelligent controller (near- real time or non-real time) hosting software or software plug-ins, such as a near-real time control application (e.g., xApp) or a non-real time control application (e.g., rApp), or any combination thereof (the adjective “open” designating support of an ORAN specification). The network node may support a specification by, for example, supporting an interface defined by the ORAN specification, such as an Al, Fl, Wl, El, E2, X2, Xn interface, an open fronthaul user plane interface, or an open fronthaul management plane interface. Moreover, an ORAN access node may be a logical node in a physical node. Furthermore, an ORAN network node may be implemented in a virtualization environment (described further below) in which one or more network functions are virtualized. For example, the virtualization environment may include an O-Cloud computing platform orchestrated by a Service Management and Orchestration Framework via an O-2 interface defined by the O- RAN Alliance or comparable technologies. The network nodes 16 facilitate direct or indirect connection of user equipment (UE), such as by connecting UEs 22a, 22b, 22c, and 22d (one or more of which may be generally referred to as UEs 22) to the core network 14 over one or more wireless connections.

[0101] FIG. 7 is a flowchart of an example process in a network node 16 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 16 such as by one or more of processing circuitry 36 (including the control information unit 24), processor 38, and / or radio interface 30. Network node 16 is configured to transmit (Block SI 00) downlink control information scheduling a first data channel, the DCI comprising a first hybrid automatic repeat request (HARQ) feedback report identifier (HRFI), as described herein. Network node 16 is configured to receive (Block SI 02) a HARQ report comprising a HARQ codebook, where the HARQ report reports a plurality of data channels associated with respective DCI containing the first HRFI, the plurality of data channels comprising the first data channel, as described herein.

[0102] According to one or more embodiments, the HARQ report is reported on layer 2.

[0103] According to one or more embodiments, the HARQ report is reported on layer 2 using a medium access control (MAC) control element (CE).

[0104] According to one or more embodiments, the HARQ report is reported on layer 1.

[0105] According to one or more embodiments, the HARQ report comprises an upper time limit specifying an upper limit in time for which HARQ feedback is to be added to the HARQ codebook.

[0106] According to one or more embodiments, the HARQ report comprises a lower time limit specifying a lower limit in time for which HARQ feedback is to be added to the HARQ codebook.

[0107] According to one or more embodiments, HARQ feedback for not yet acknowledged data channels of the plurality of data channels are included in the HARQ codebook.

[0108] According to one or more embodiments, the HARQ-acknowledgement (HARQ- ACK) feedback size for transmission the first data channel is reduced based on at least one configuration, the at least one configuration comprising at least one of: a configuration for providing an association between a downlink serving cell and an uplink serving cell; and a configuration for providing groping of HARQ process identifiers for a downlink serving cell.

[0109] According to some embodiments, a method is implemented in a network node. The network node is configured to communicate with a user equipment (UE). The method comprises transmitting (like in Block SI 00 in FIG. 7) a plurality of control information messages scheduling respective transmissions to the UE. The method comprises receiving (like in Block SI 02 in FIG. 7), from the UE, reporting of acknowledgements of reception of the scheduled transmissions. The control information messages comprise feedback report identifiers indicating which of the scheduled transmissions to be acknowledged in the same report. The reporting is based on the feedback report identifiers. FIG. 8 is a flowchart of an example process in a user equipment 22 according to some embodiments of the present disclosure. One or more blocks described herein may be performed by one or more elements of user equipment 22 such as by one or more of processing circuitry 50 (including the reporting unit 26), processor 52, and / or radio interface 46. UE 22 is configured to receive (Block SI 04) downlink control information scheduling a first data channel, where the DCI comprises a first hybrid automatic repeat request (HARQ) feedback report identifier (HRFI), as described herein. UE 22 is configured to report (Block SI 06), in a HARQ codebook of a HARQ report, a plurality of data channels associated with respective DCI containing the first HRFI, the plurality of data channels comprising the first data channel, as described herein.

[0110] According to one or more embodiments, the HARQ report is reported on layer 2.

[0111] According to one or more embodiments, the reporting uses a medium access control (MAC) control element (CE).

[0112] According to one or more embodiments, the HARQ report is reported on layer 1.

[0113] According to one or more embodiments, the HARQ report comprises an upper time limit specifying an upper limit in time for which HARQ feedback is to be added to the HARQ codebook.

[0114] According to one or more embodiments, the HARQ report comprises a lower time limit specifying a lower limit in time for which HARQ feedback is to be added to the HARQ codebook.

[0115] According to one or more embodiments, HARQ feedback for not yet acknowledged data channels of the plurality of data channels are included in the HARQ codebook.

[0116] According to one or more embodiments, the HARQ-acknowledgement (HARQ- ACK) feedback size for transmission the first data channel is reduced based on at least one configuration, the at least one configuration comprising at least one of: a configuration for providing an association between a downlink serving cell and an uplink serving cell; and a configuration for providing groping of HARQ process identifiers for a downlink serving cell.

[0117] According to some embodiments, a method is implemented in a user equipment (UE). The UE is configured to communicate with a network node. The method comprises receiving (like in Block SI 04 in FIG. 8) a plurality of control information messages scheduling respective transmissions to the UE. The method comprises reporting (like in Block S106 in FIG. 8) acknowledgements of reception of the scheduled transmissions. The control information messages comprise feedback report identifiers indicating which of the scheduled transmissions to be acknowledged in the same report. The reporting is performed based on the feedback report identifiers.

[0118] FIG. 9 is a block diagram illustrating a virtualization environment 94 in which functions implemented by some embodiments may be virtualized. In the present context, virtualizing means creating virtual versions of apparatuses or devices which may include virtualizing hardware platforms, storage devices and networking resources. As used herein, virtualization can be applied to any device described herein, or components thereof, and relates to an implementation in which at least a portion of the functionality is implemented as one or more virtual components. Some or all of the functions described herein may be implemented as virtual components executed by one or more virtual machines (VMs) implemented in one or more virtual environments 94 hosted by one or more of hardware nodes, such as a hardware computing device that operates as a network node, UE, core network node, or host. Further, in embodiments in which the virtual node does not require radio connectivity (e.g., a core network node or host), then the node may be entirely virtualized. In some embodiments, the virtualization environment 94 includes components defined by the O-RAN Alliance, such as an O-Cloud environment orchestrated by a Service Management and Orchestration Framework via an 0-2 interface.

[0119] Applications 96 (which may alternatively be called software instances, virtual appliances, network functions, virtual nodes, virtual network functions, etc.) are run in the virtualization environment 94 to implement some of the features, functions, and / or benefits of some of the embodiments disclosed herein.

[0120] Hardware 98 includes processing circuitry, memory that stores software and / or instructions executable by hardware processing circuitry, and / or other hardware devices as described herein, such as a network interface, input / output interface, and so forth. Software may be executed by the processing circuitry to instantiate one or more virtualization layers 100 (also referred to as hypervisors or virtual machine monitors (VMMs)), provide VMs 102a and 102b (one or more of which may be generally referred to as VMs 102), and / or perform any of the functions, features and / or benefits described in relation with some embodiments described herein. The virtualization layer 100 may present a virtual operating platform that appears like networking hardware to the VMs 102.

[0121] The VMs 102 comprise virtual processing, virtual memory, virtual networking or interface and virtual storage, and may be run by a corresponding virtualization layer 100. Different embodiments of the instance of a virtual appliance 96 may be implemented on one or more of VMs 102, and the implementations may be made in different ways. Virtualization of the hardware is in some contexts referred to as network function virtualization (NFV). NFV may be used to consolidate many network equipment types onto industry standard high volume server hardware, physical switches, and physical storage, which can be located in data centers, and customer premise equipment.

[0122] In the context of NFV, a VM 102 may be a software implementation of a physical machine that runs programs as if they were executing on a physical, non-virtualized machine. Each of the VMs 102, and that part of hardware 98 that executes that VM, be it hardware dedicated to that VM and / or hardware shared by that VM with others of the VMs, forms separate virtual network elements. Still in the context of NFV, a virtual network function is responsible for handling specific network functions that run in one or more VMs 102 on top of the hardware 98 and corresponds to the application 96.

[0123] Hardware 98 may be implemented in a standalone network node with generic or specific components. Hardware 98 may implement some functions via virtualization. Alternatively, hardware 98 may be part of a larger cluster of hardware (e.g. such as in a data center or CPE) where many hardware nodes work together and are managed via management and orchestration 104, which, among others, oversees lifecycle management of applications 96. In some embodiments, hardware 98 is coupled to one or more radio units that each include one or more transmitters and one or more receivers that may be coupled to one or more antennas. Radio units may communicate directly with other hardware nodes via one or more appropriate network interfaces and may be used in combination with the virtual components to provide a virtual node with radio capabilities, such as a radio access node or a base station. In some embodiments, some signaling can be provided with the use of a control system 106 which may alternatively be used for communication between hardware nodes and radio units.

[0124] Having described the general process flow of arrangements of the disclosure and having provided examples of hardware and software arrangements for implementing the processes and functions of the disclosure, the sections below provide details and examples of arrangements for acknowledgements of received transmissions.

[0125] Some embodiments provide HARQ feedback using layer 2. One or more UE 22 functions described below may be performed by one or more of processing circuitry 50, processor 52, reporting unit 26, radio interface 46, etc. One or more network node 16 functions described below may be performed by one or more of processing circuitry 36, processor 38, control information unit 24, radio interface 30, etc.

[0126] Embodiment 1:

[0127] The DL assignment (e.g., downlink control information (DCI)) scheduling a PDSCH includes a HARQ Feedback Report Identifier (HFRI) that instructs the UE 22 to report HARQ feedback of PDSCHs which scheduling DCIs contain the same HFRI in the same HARQ codebook. The HFRI thus replaces the slot offset indicator and PUCCH resource indicator in NR. To avoid error cases, it may be assumed that the mechanisms described herein are specified how to handle missed DL assignments (DCI), one such mechanism is the DAI mechanism described herein.

[0128] The UE 22 then constructs a HARQ report. This HARQ report consists of the HARQ codebook plus the HFRI. The HFRI enables the network node 16 to determine the downlink transmissions the HARQ feedback corresponds to (the network node 16 included the HFRI in the scheduling DCIs).

[0129] One example of the HARQ codebook construction is that the HARQ feedback bits corresponding to reception of PDSCHs whose scheduling DCIs contain the same HFRI are sorted according to a carrier first, time second manner of the scheduling PDCCH.

[0130] At some point in time the UE 22 must stop adding HARQ feedback to a HARQ codebook and prepare the HARQ report for transmission.

[0131] • One possibility would be a UE-autonomous decision based on a configured timeout value: if the UE 22 has not received DL assignments (DCI) with a same HFRI for a configured amount of time, the UE 22 will not expect any more DL assignments (DCI) for this HARQ report.

[0132] • Another possibility is that a UE 22 does not expect any more DL assignments (DCI) with a same HFRI as soon as it has received a DL assignment (DCI) with another HFRI. If HFRIs can be configured with different priority levels, this rule could be limited to HFRI of same priority. This rule can also be combined with a timeout.

[0133] • Yet another option is to include an additional bit in the DL assignment (DCI) that indicates that no further DL assignment (DCI) should be included in this HARQ report. This bit could be added to DL assignments (DCI) on all carriers (similar to the total DAI) to minimize error cases due to lost DL assignment (DCI).

[0134] • A further alternative is that the UE 22 takes an autonomous decision when to stop adding additional HARQ feedback bits. The UE 22 may then need to include an indicator in the HARQ report indicating which is the last DL assignment (DCI) that is acknowledged in the report. When the network node 16 sends further DL assignment (DCI) with the same HFRI the UE 22 reports the corresponding HARQ feedback in a later report for this HFRI. The indicator is either explicit (preferred) or implicit (less preferred) (e.g., all DCIs up to a fixed / configured time (expressed in slots, subframes, symbols, PDCCH monitoring occasions) before the PUSCH containing the report or the PDCCH scheduling the PUSCH. In this case, no extra bits need to be added to the HARQ report.).

[0135] In some cases, the DCI providing some command to a UE 22, e.g., to activate / deactivate some configuration or to switch a configuration, etc., includes an HFRI. In such cases, the feedback corresponding to the successful reception of such commands can be included in the same HARQ codebook with the same HFRI. One example of how the feedback corresponding to successful reception of the command DCI is included is to append the feedback of command DCI to the HARQ feedback bits of the PDSCHs. This provides added clarity. Another possibility is to insert the DCI command feedback in the HARQ codebook based on the carrier and time (PDCCH occurrence) the command DCI has been sent.

[0136] Transmission on L2

[0137] The UE 22 then determines when to transmit the HARQ report on layer 2 (L2) using PUSCH. Different mechanisms can be envisioned how the UE 22 determines when to send the HARQ report. One way is that HARQ reports have a priority level and this priority is used in the multiplexing and assembly procedure to determine when the HARQ report is sent. Different HFRI can be a configured with a different priority level, enabling that a high priority HARQ report is prioritized over lower priority UL transmission while HARQ reports of lower priority are multiplexed with lower priority. In some examples, an uplink scheduling grant includes a priority level indication. Any HARQ report with the same or higher priority level can be included in the transport block of the PUSCH transmission.

[0138] It may be desirable that the HARQ report is transmitted as a MAC CE and encoded using Abstract Syntax Notation. One (ASN.1), but other transmission formats and encoding schemes are possible as well.

[0139] If a network node 16 schedules a UE 22 with different HFRI values the UE 22 would prepare different HARQ reports. Multiple HARQ reports prioritized by the multiplexing and assembly procedure to be transmitted in the same UL transmission can thus be multiplexed into the same UL transmission. These reports can either be part of the same or different MAC CEs; at least if the different reports correspond to HFRI value of different priorities they are preferable transmitted using separate MAC CEs.

[0140] Transmission on LI

[0141] The HARQ report may be transmitted on layer 1 (LI), e.g., via PUCCH or as UCI on PUSCH. Transmission on LI may be more suitable for those options where the size of the HARQ report is known to the network node 16.

[0142] Transmission requested by UL grant containing HFRI

[0143] In some cases, the UL scheduling grant sent to a UE 22 contains an HFRI indicating that it requests the HARQ feedback with the same HRFI as the indicated HFRI to be transmitted on the scheduled PUSCH. In these cases, the UE 22 does not need to include the HFRI. The HARQ feedback can be transmitted on LI, e.g., as UCI on PUSCH or on L2 as MAC-CE multiplexed with the uplink (UL) data according to a certain rule. Embodiment 2:

[0144] In this embodiment, the UE 22 autonomously determines or decides upon an upper time (or PDCCH monitoring occasion) limit of received DL assignments (DCI) for which it should include HARQ feedback (more precisely, for which PDSCHs scheduled by the DCIs it should include HARQ feedback) in the HARQ codebook. This upper time limit can be expressed in any of and combinations of symbols, slots, subframes, frames, PDCCH monitoring occasions, either absolute (e.g. based on frame number and symbols, slots, subframes therein) or relative (e.g. in symbols, slots, subframes, PDCCH monitoring occasions relative to the PUSCH transmission containing the HARQ report or relative to the DCI scheduling the PUSCH).

[0145] The UE 22 then constructs a dynamic HARQ codebook which together with the upper time limit forms the HARQ report. To avoid error cases, it may be assumed that mechanisms are specified how to handle missed DL assignments (DCI), one such mechanism is the DAI mechanism as described herein. This HARQ report is then transmitted as L2 feedback on PUSCH.

[0146] In addition to the upper limit also a lower limit excluding too old DL assignments (DCI) may be used. This lower limit can either be expressed like the upper limit or as a time span (assuming the upper limit is t0and the time span T, the lower limit would be t0— T) expressed in symbols, slots, subframes, PDCCH monitoring occasions.

[0147] Another alternative would be to include HARQ feedback for all PDSCHs scheduled by DL assignments (DCI) which the UE 22 has not yet acknowledged. If a DAI solution similar to the solution described in the “Scheduling” section above is applied and if the first DCI to be included in the HARQ codebook contains a counter DAI that is by more than one higher than the counter DAI contained in the last acknowledged DCI (larger ignoring wrap around due to modulo operation) the UE 22 knows it missed one or multiple DCIs and may need to include them as NACK in the HARQ codebook.

[0148] If the DL assignment (DCI) contains information from which the UE 22 can derive a priority of the scheduled PDSCH, different HARQ reports can be constructed for the different priority levels.

[0149] If a UE 22 is configured to receive semi-persistently scheduled (SPS) PDSCH, the UE 22 considers including a feedback bit corresponding to the reception of the SPS PDSCH in the HARQ feedback codebook if the SPS PDSCH is located within the upper and lower time limits described above. One example of how the feedback corresponding to the reception of the SPS PDSCH is included in the codebook is to append the feedback bit to the HARQ feedback bits of PDSCHs scheduled by some DCI format.

[0150] (similar as in Embodiment 1 above) Different mechanisms can be provided for how the UE 22 determines when to send the HARQ report. One way is that HARQ reports have a priority level and this priority is used in the multiplexing and assembly procedure to determine when the HARQ report is sent. If different priority levels are supported, a high priority HARQ report is prioritized over lower priority UL transmission while HARQ reports of lower priority are multiplex with lower priority.

[0151] (same as in Embodiment 1 above) The HARQ report may be transmitted as a MAC CE and encoded using ASN.l, but other transmission formats and encoding schemes are possible as well.

[0152] (similar as in Embodiment 1 above) Multiple HARQ reports prioritized by multiplexing and assembly procedure to be transmitted in the same UL transmission can thus be multiplexed into the same UL transmission. These reports can either be part of the same or different MAC CEs; at least if the different reports correspond to different priorities, they are preferable transmitted using separate MAC CEs.

[0153] Embodiment 3:

[0154] Compression on the DL serving cell level:

[0155] The HARQ-ACK feedback report is transmitted on a PUSCH that is scheduled on a serving cell, Cu(i). By configuration, one can associate that the serving cell Cu is associated with respect to HARQ-ACK feedback to a set or multiple sets of serving cell(s) where UE 22 receives DL transmissions, for example Cd(j).

[0156] • For example, by introducing 2 sets, the amount of HARQ-ACK feedback in a PUSCH transmission is halved per PUSCH transmission.

[0157] Compression on HARQ process per DL serving cell level:

[0158] The HARQ process IDs (HPIDs) corresponding to a DL serving cell can be partitioned into groups. For example, if a DL serving cell is configured with 16 HARQ processes. Two groups for HPIDs {0, ..„ 7} and {8,.., 15} can be configured. A PUSCH provides the HARQ-ACK feedback report corresponding to one of these groups. The group ID used for reporting can be provided by configuration associated to the PUSCH transmission, or by indication in the corresponding UL grant.

[0159] In another example, maximum number of HPIDs with corresponding HARQ-ACK can be provided, for example by configuration. The smallest index HPID for reporting can be provided by the UL DCI.

[0160] In another example, the HARQ-ACK feedback corresponding to HARQ process IDs on a serving cell can be bundled into one or multiple groups.

[0161] Some examples for teachings of the Embodiment 3 are given below:

[0162] Assume there are 4 DL serving cells, Cd(l) to Cd(4), each configured with 16 HARQ process IDs (HPIDs). Further assume there are two UL scheduled cells Cu(l) and Cu(2). Note that without any compression, the size of the HARQ-ACK feedback for each PUSCH transmitted on Cu(l) or Cu(2) is 4X16= 64 bits.

[0163] For compression across DL serving cells,

[0164] Example 1

[0165] • Cu(l) is configured with HARQ-ACK feedback associated to Cd(l) and Cd(2). o The size of HARQ-ACK feedback a PUSCH transmitted on Cu(l) is 2X16= 32 bits.

[0166] • Cu(2) is configured with HARQ-ACK feedback associated to Cd(3) and Cd(4). o The size of HARQ-ACK feedback a PUSCH transmited on Cu(2) is 2X16= 32 bits.

[0167] Example 2

[0168] • 1 bit in UL grant indicates whether HARQ-ACK feedback is associated to Cd(l) and Cd(2), or Cd(3) and Cd(4). o The size of HARQ-ACK feedback a PUSCH transmited is 2X16= 32 bits.

[0169] Example 3

[0170] • 1 bit in UL grant indicates whether HARQ-ACK feedback is associated to Group 1 or Group 2 for Cd(l) and Cd(2), or Cd(3) and Cd(4).

[0171] • Or, PUSCH on Cu(l) or Cu(2) carries HARQ-ACK feedback associated to Group 1 or Group 2, respectively, for Cd(l) and Cd(2), or Cd(3) and Cd(4).

[0172] • Note: The associated DL serving cells can be reduced as in Example 1 or 2. Example 4

[0173] • Maximum number of HP ID is configured to be 6. For example, UL grant indicates starting HP ID = 3. Then, for each DL serving cell associated to the cell with the scheduled PUSCH, the HARQ-ACK feedback corresponds to associated HP ID {3, 4, 5, 6, 7, 8}.

[0174] • Note: The associated DL serving cells can be reduced as in Example 1 or 2.

[0175] • Note: The associated HARQ processes can be reduced as in Example 3. Example 5

[0176] • Two bundling groups per DL serving cell. Then, one HARQ-ACK bit is reported per bundle group.

[0177] • Note: the bundling can be applied to any of the examples above.

[0178] Some embodiments and examples In view of the description above, one or more embodiments enable asynchronous HARQ feedback transmitted on L2 without substantially increasing HARQ feedback size, e.g., without increasing HARQ feedback size over at threshold and / or at least when compared to existing HARQ feedback size. This improves link budget of the HARQ feedback transmission (fewer bits to transmit) and reduces feedback overhead.

[0179] Some embodiments advantageously provide methods, systems, and apparatuses for HARQ feedback using layer 2 (L2).

[0180] One or more embodiments described herein provides for a dynamic HARQ codebook that can be used for L2 reporting, with only small (e.g., minimal) additional overhead at least when compared to existing systems.

[0181] First group of examples:

[0182] Example 1AA. DL assignment (DCI) that schedules PDSCH contains a HARQ Feedback Report Identifier (HFRI). PDSCHs which scheduling DCI contain the same HFRI are reported in the same HARQ codebook.

[0183] Example 2AA. Example 1 AA where the UE adds the HFRI to the HARQ report (HARQ codebook plus HFRI).

[0184] Example 3AA. Example 2AA where the HARQ report is transmitted on L2.

[0185] Example 4AA. Example 3AA where the L2 transmission uses a Medium

[0186] Access Control (MAC) Control Element (CE).

[0187] Example 5AA. Example 4AA where the MAC CE is encoded using Abstract Syntax Notation. One (ASN.l).

[0188] Example 6AA. Example 2AA where the HARQ report is transmitted on layer 1 (LI).

[0189] Second group of examples:

[0190] Example IBB. The HARQ report contains the HARQ codebook plus an upper time limit specifying an upper limit in time which DL assignments (DCI) (more precisely: HARQ feedback of PDSCHs scheduled by the DCIs) should be added to the HARQ codebook.

[0191] Example 2BB. Example IBB where a lower time limit specifying a lower limit in time which DL assignments (DCI) (more precisely: HARQ feedback of PDSCHs scheduled by the DCIs) should be added to the HARQ codebook.

[0192] Example 3BB. Example IBB where HARQ feedback for all not yet acknowledged PDSCH (up to the upper time limit defined in Example IBB) are included in the HARQ codebook. Third group of examples:

[0193] Example ICC. The HARQ-ACK feedback size on a PUSCH transmission on a scheduled cell can be reduced by flexible configurations of the corresponding DL serving cells and associated HARQ process IDs. The reduced size can be provided by configuration for HARQ-ACK codebook associated to the scheduled cell or indication in the UL grant DCI to a candidate among available configurations associated to the scheduled cell. a. The configurations can provide DL serving cell to UL serving cell association for the purpose of HARQ-ACK reporting. b. The configurations can provide grouping or bundling or limiting of HARQ process ID s for a DL serving cell for the purpose of HARQ-ACK reporting. c. Above Examples can be combined.

[0194] Miscellaneous

[0195] As will be appreciated by one of skill in the art, the concepts described herein may be embodied as a method, data processing system, computer program product and / or computer storage media storing an executable computer program. Accordingly, the concepts described herein may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects all generally referred to herein as a “circuit” or “module.” Any process, step, action and / or functionality described herein may be performed by, and / or associated to, a corresponding module, which may be implemented in software and / or firmware and / or hardware. Furthermore, the disclosure may take the form of a computer program product on a tangible computer usable storage medium having computer program code embodied in the medium that can be executed by a computer. Any suitable tangible computer readable medium may be utilized including hard disks, CD-ROMs, electronic storage devices, optical storage devices, or magnetic storage devices.

[0196] Some embodiments are described herein with reference to flowchart illustrations and / or block diagrams of methods, systems and computer program products. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer (to thereby create a special purpose computer), special purpose computer, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions / acts specified in the flowchart and / or block diagram block or blocks.

[0197] These computer program instructions may also be stored in a computer readable memory or storage medium that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer readable memory produce an article of manufacture including instruction means which implement the function / act specified in the flowchart and / or block diagram block or blocks.

[0198] The computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions / acts specified in the flowchart and / or block diagram block or blocks.

[0199] It is to be understood that the functions / acts noted in the blocks may occur out of the order noted in the operational illustrations. For example, two blocks shown in succession may in fact be executed substantially concurrently or the blocks may sometimes be executed in the reverse order, depending upon the functionality / acts involved. Although some of the diagrams include arrows on communication paths to show a primary direction of communication, it is to be understood that communication may occur in the opposite direction to the depicted arrows.

[0200] 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++. However, the computer program code for carrying out operations of the disclosure may also be written in conventional procedural programming languages, such as the "C" programming language. The program code may execute entirely on the user's computer, partly on the user's computer, as a stand-alone software package, partly on the user's computer and partly on a remote computer or entirely on the remote computer. In the latter scenario, the remote computer may be connected to the user's computer through a local area network (LAN) or a wide area network (WAN), or the connection may be made to an external computer (for example, through the Internet using an Internet Service Provider). Many different embodiments have been disclosed herein, in connection with the above description and the drawings. It will be understood that it would be unduly repetitious and obfuscating to literally describe and illustrate every combination and subcombination of these embodiments. Accordingly, all embodiments can be combined in any way and / or combination, and the present specification, including the drawings, shall be construed to constitute a complete written description of all combinations and subcombinations of the embodiments described herein, and of the manner and process of making and using them, and shall support claims to any such combination or subcombination.

[0201] It will be appreciated by persons skilled in the art that the embodiments described herein are not limited to what has been particularly shown and described herein above. In addition, unless mention was made above to the contrary, it should be noted that all of the accompanying drawings are not to scale. A variety of modifications and variations are possible in light of the above teachings.

[0202] Embodiments:

[0203] Embodiment Al . A method implemented in a user equipment (UE) that is configured to communicate with a network node, the method comprising receiving downlink control information scheduling a first data channel, the DCI comprising a first hybrid automatic repeat request (HARQ) feedback report identifier (HRFI); and reporting, in a HARQ codebook of a HARQ report, a plurality of data channels associated with respective DCI containing the first HRFI, the plurality of data channels comprising the first data channel.

[0204] Embodiment A2. The method of Embodiment Al, wherein the HARQ report is reported on layer 2.

[0205] Embodiment A3. The method of Embodiment A2, wherein the reporting uses a medium access control (MAC) control element (CE).

[0206] Embodiment A4. The method of Embodiment Al, wherein the HARQ report is reported on layer 1. Embodiment A5. The method of Embodiments Al, wherein the HARQ report comprises an upper time limit specifying an upper limit in time for which HARQ feedback is to be added to the HARQ codebook.

[0207] Embodiment A6. The method of Embodiment A5, wherein the HARQ report comprises a lower time limit specifying a lower limit in time for which HARQ feedback is to be added to the HARQ codebook.

[0208] Embodiment A7. The method of any one of Embodiments A5-A6, wherein HARQ feedback for not yet acknowledged data channels of the plurality of data channels are included in the HARQ codebook.

[0209] Embodiment A8. The method of any one of Embodiments A1-A7, wherein the HARQ-acknowledgement (HARQ-ACK) feedback size for transmission the first data channel is reduced based on at least one configuration, the at least one configuration comprising at least one of: a configuration for providing an association between a downlink serving cell and an uplink serving cell; and a configuration for providing groping of HARQ process identifiers for a downlink serving cell.

[0210] Embodiment Bl . A user equipment (UE) configured to communicate with a network node, the UE configured to, and / or comprising a radio interface and / or processing circuitry configured to: receive downlink control information scheduling a first data channel, the DCI comprising a first hybrid automatic repeat request (HARQ) feedback report identifier (HRFI); and report, in a HARQ codebook of a HARQ report, a plurality of data channels associated with respective DCI containing the first HRFI, the plurality of data channels comprising the first data channel.

[0211] Embodiment B2. The UE of Embodiment B 1 , wherein the HARQ report is reported on layer 2. Embodiment B3. The UE of Embodiment B2, wherein the reporting uses a medium access control (MAC) control element (CE).

[0212] Embodiment B4. The UE of Embodiment B 1 , wherein the HARQ report is reported on layer 1.

[0213] Embodiment B5. The UE of Embodiments B 1 , wherein the HARQ report comprises an upper time limit specifying an upper limit in time for which HARQ feedback is to be added to the HARQ codebook.

[0214] Embodiment B6. The UE of Embodiment B5, wherein the HARQ report comprises a lower time limit specifying a lower limit in time for which HARQ feedback is to be added to the HARQ codebook.

[0215] Embodiment B7. The UE of any one of Embodiments B5-B6, wherein HARQ feedback for not yet acknowledged data channels of the plurality of data channels are included in the HARQ codebook.

[0216] Embodiment B8. The UE of any one of Embodiments B1-B7, wherein the

[0217] HARQ-acknowledgement (HARQ-ACK) feedback size for transmission the first data channel is reduced based on at least one configuration, the at least one configuration comprising at least one of: a configuration for providing an association between a downlink serving cell and an uplink serving cell; and a configuration for providing groping of HARQ process identifiers for a downlink serving cell.

[0218] Embodiment Cl . A method implemented in a network node that is configured to communicate with a user equipment, the method comprising: transmitting downlink control information scheduling a first data channel, the DCI comprising a first hybrid automatic repeat request (HARQ) feedback report identifier (HRFI); and receiving a HARQ report comprising a HARQ codebook, the HARQ report reporting a plurality of data channels associated with respective DCI containing the first HRFI, the plurality of data channels comprising the first data channel.

[0219] Embodiment C2. The method of Embodiment Cl, wherein the HARQ report is reported on layer 2.

[0220] Embodiment C3. The method of Embodiment C2, wherein the HARQ report is reported on layer 2 using a medium access control (MAC) control element (CE).

[0221] Embodiment C4. The method of Embodiment Cl, wherein the HARQ report is reported on layer 1.

[0222] Embodiment C5. The method of Embodiments Cl, wherein the HARQ report comprises an upper time limit specifying an upper limit in time for which HARQ feedback is to be added to the HARQ codebook.

[0223] Embodiment C6. The method of Embodiment C5, wherein the HARQ report comprises a lower time limit specifying a lower limit in time for which HARQ feedback is to be added to the HARQ codebook.

[0224] Embodiment C7. The method of any one of Embodiments C5-C6, wherein HARQ feedback for not yet acknowledged data channels of the plurality of data channels are included in the HARQ codebook.

[0225] Embodiment C8. The method of any one of Embodiments C1-C7, wherein the HARQ-acknowledgement (HARQ-ACK) feedback size for transmission the first data channel is reduced based on at least one configuration, the at least one configuration comprising at least one of: a configuration for providing an association between a downlink serving cell and an uplink serving cell; and a configuration for providing groping of HARQ process identifiers for a downlink serving cell. Embodiment DI. A network node configured to communicate with a user equipment (UE), the network node configured to, and / or comprising a radio interface and / or comprising processing circuitry configured to: transmit downlink control information scheduling a first data channel, the DCI comprising a first hybrid automatic repeat request (HARQ) feedback report identifier (HRFI); and receive a HARQ report comprising a HARQ codebook, the HARQ report reporting a plurality of data channels associated with respective DCI containing the first HRFI, the plurality of data channels comprising the first data channel.

[0226] Embodiment D2. The network node of Embodiment D 1 , wherein the HARQ report is reported on layer 2.

[0227] Embodiment D3. The network node of Embodiment D2, wherein the HARQ report is reported on layer 2 using a medium access control (MAC) control element (CE).

[0228] Embodiment D4. The network node of Embodiment D 1 , wherein the HARQ report is reported on layer 1.

[0229] Embodiment D5. The network node of Embodiments D 1 , wherein the HARQ report comprises an upper time limit specifying an upper limit in time for which HARQ feedback is to be added to the HARQ codebook.

[0230] Embodiment D6. The network node of Embodiment D5, wherein the HARQ report comprises a lower time limit specifying a lower limit in time for which HARQ feedback is to be added to the HARQ codebook.

[0231] Embodiment D7. The network node of any one of Embodiments D5-D6, wherein HARQ feedback for not yet acknowledged data channels of the plurality of data channels are included in the HARQ codebook.

[0232] Embodiment D8. The network node of any one of Embodiments D1-D7, wherein the HARQ-acknowledgement (HARQ-ACK) feedback size for transmission the first data channel is reduced based on at least one configuration, the at least one configuration comprising at least one of: a configuration for providing an association between a downlink serving cell and an uplink serving cell; and a configuration for providing groping of HARQ process identifiers for a downlink serving cell.

[0233] Embodiment El. A method implemented in a user equipment, UE, that is configured to communicate with a network node, the method comprising: receiving a plurality of control information messages scheduling respective transmissions to the UE; and reporting acknowledgements of reception of the scheduled transmissions, wherein the UE sends a report comprising acknowledgements of reception of scheduled transmissions, and wherein the report comprises an upper time limit specifying an upper limit in time for which scheduled transmissions are acknowledged in the report.

[0234] Embodiment E2. The method of Embodiment El, wherein the report comprises a lower time limit specifying a lower limit in time for which scheduled transmissions are acknowledged in the report.

[0235] Embodiment E3. The method of Embodiment El, wherein acknowledgements for not yet acknowledged transmissions up until the upper time limit are included in the report.

[0236] Embodiment E4. The method of any of Embodiments E1-E3, wherein the UE is configured to receive a semi-persistently scheduled transmission before the upper time limit, and wherein the report includes an acknowledgement of reception of the semi- persistently scheduled transmission.

[0237] Embodiment Fl . A user equipment (UE) configured to communicate with a network node, the UE configured to, and / or comprising a radio interface and / or processing circuitry configured to perform the method of any of Embodiments E1-E4.

[0238] Embodiment G1. A method implemented in a network node that is configured to communicate with a user equipment, UE, the method comprising: transmitting a plurality of control information messages scheduling respective transmissions to the UE; and receiving, from the UE, reporting of acknowledgements of reception of the scheduled transmissions, wherein the network node receives a report comprising acknowledgements of reception of scheduled transmissions, and wherein the report comprises an upper time limit specifying an upper limit in time for which scheduled transmissions are acknowledged in the report.

[0239] Embodiment G2. The method of Embodiment Gl, wherein the report comprises a lower time limit specifying a lower limit in time for which scheduled transmissions are acknowledged in the report.

[0240] Embodiment G3. The method of Embodiment Gl, wherein acknowledgements for not yet acknowledged transmissions up until the upper time limit are included in the report.

[0241] Embodiment Hl . A network node configured to communicate with a user equipment, UE , the network node configured to, and / or comprising a radio interface and / or processing circuitry configured to perform the method of any of Embodiments GIGS.

Claims

CLAIMS1. A method implemented in a user equipment, UE (22), that is configured to communicate with a network node (16), the method comprising: receiving (SI 04) a plurality of control information messages scheduling respective transmissions to the UE; and reporting (SI 06) acknowledgements of reception of the scheduled transmissions, wherein the control information messages comprise feedback report identifiers indicating which of the scheduled transmissions to be acknowledged in the same report, and wherein the reporting is performed based on the feedback report identifiers.

2. The method of claim 1, wherein a first report from the UE includes acknowledgements for transmissions scheduled by control messages comprising a first feedback report identifier.

3. The method of claim 2, wherein the first report includes the first feedback report identifier.

4. The method of any of the preceding claims, wherein the reporting is provided on layer 2.

5. The method of claim 4, wherein the reporting uses a medium access control, MAC, control element, CE.

6. The method of any of claims 1-3, wherein the reporting is provided on layer 1.

7. The method of any of the preceding claims, wherein the reported acknowledgements are hybrid automatic repeat request, HARQ, feedback.

8. The method of any of the preceding claims, wherein: if the UE has not received any control information messages with a first feedback report identifier for a certain amount of time, the UE prepares a report for transmission based on acknowledgments of reception of transmissions scheduled by earlier control information messages comprising the first feedback report identifier; orif the UE has received control information messages comprising a first feedback report identifier and then receives a control information message comprising a second feedback report identifier, the UE prepares a report for transmission based on acknowledgements of reception of transmissions scheduled by the control information messages comprising the first feedback report identifier; or if the UE has received control information messages comprising a first feedback report identifier and then receives a control information message comprising a second feedback report identifier of the same priority level as the first feedback report identifier, the UE prepares a report for transmission based on acknowledgements of reception of transmissions scheduled by the control information messages comprising the first feedback report identifier; or if the UE receives a control information message comprising an indicator indicating that no further acknowledgements should be included in a report, the UE prepares the report for transmission based on acknowledgements of reception of transmissions already scheduled by received control information messages; or when the UE prepares a report for transmission based on acknowledgements of reception of transmissions scheduled by received control information messages, the UE includes an indicator in the report indicating which is the last control information message scheduling a transmission that is acknowledged in the report.

9. The method of any of the preceding claims, wherein a first report from the UE includes acknowledgements for transmissions scheduled by control information messages comprising a first feedback report identifier, wherein the UE receives control information which provides a command and which also comprises the first feedback report identifier, and wherein the first report includes an acknowledgement of the command.

10. The method of any of the preceding claims, wherein a downlink assignment index, DAI, mechanism is used for handling missed control messages.

11. The method of any of the preceding claims, wherein the feedback report identifiers have priority levels, and wherein the UE uses the priority levels to determine which acknowledgements to be included in a report.

12. The method of claim 11, comprising:receiving control information scheduling a transmission from the UE, wherein the control information scheduling a transmission from the UE includes an indication of a first priority level, wherein the report is transmitted as part of the scheduled transmission, and wherein the report includes acknowledgements of reception of transmissions scheduled by received control information messages including feedback report identifiers with a priority level at least as high as the first priority level.

13. The method of any of the preceding claims, wherein the reporting includes reports associated with different feedback report identifiers, and wherein reports associated with feedback report identifiers of different priority levels are transmitted using separate medium access control, MAC, control elements, CE.

14. The method of any of the preceding claims, comprising: receiving control information scheduling a transmission from the UE, wherein the control information scheduling a transmission from the UE includes a first feedback report identifier, and wherein acknowledgements of reception of transmissions scheduled by received control information messages including the first feedback report identifier are reported as part of the scheduled transmission from the UE.

15. The method of any of the preceding claims, wherein the UE sends a report comprising acknowledgements of reception of scheduled transmissions, and wherein the report comprises an upper time limit specifying an upper limit in time for which scheduled transmissions are acknowledged in the report.

16. The method of claim 15, wherein the report comprises a lower time limit specifying a lower limit in time for which scheduled transmissions are acknowledged in the report.

17. The method of claim 15, wherein acknowledgements for not yet acknowledged transmissions up until the upper time limit are included in the report.

18. The method of any of claims 15-17, wherein the UE is configured to receive a semi- persistently scheduled transmission before the upper time limit, and wherein the report includes an acknowledgement of reception of the semi-persistently scheduled transmission.

19. The method of any of the preceding claims, wherein: the UE is capable of receiving transmissions from a plurality of cells, the UE is configured to provide acknowledgements of reception of transmissions from a first subset of the plurality of cells using a first cell, and the UE is configured to provide acknowledgements of reception of transmissions from a second subset of the plurality of cells using a second cell; and / or the UE is capable of receiving transmissions associated with a plurality of hybrid automatic repeat request, HARQ, process identifiers, the UE is configured to provide acknowledgements of reception of transmissions for a first subset of the HARQ process identifiers using a first cell, and the UE is configured to provide acknowledgements of reception of transmissions for a second subset of the HARQ process identifiers using a second cell.

20. The method of any of claims 1-18, wherein: the UE is capable of receiving transmissions from a plurality of cells, the UE is configured with a first subset of the plurality of cells and a second subset of the plurality of cells, the UE receives control information scheduling a transmission from the UE, the control information scheduling a transmission from the UE indicates the first or second subset of the plurality of cells, and the UE includes acknowledgments of reception of transmissions for the indicated subset of the plurality of cells in the reporting; or the UE is capable of receiving transmissions associated with a plurality of hybrid automatic repeat request, HARQ, process identifiers, the UE is configured with a first subset of the plurality of HARQ process identifiers and a second subset of the plurality of HARQ process identifiers, the UE receives control information scheduling a transmission from the UE, the control information scheduling a transmission from the UE indicates the first or second subset of the plurality of HARQ process identifiers, and the UE includes acknowledgments of reception of transmissions for the indicated subset of the plurality of HARQ process identifiers in the reporting.

21. A method implemented in a network node (16) that is configured to communicate with a user equipment, UE (22), the method comprising: transmitting (SI 00) a plurality of control information messages scheduling respective transmissions to the UE; and receiving (SI 02), from the UE, reporting of acknowledgements of reception of the scheduled transmissions, wherein the control information messages comprise feedback report identifiers indicating which of the scheduled transmissions to be acknowledged in the same report, and wherein the reporting is based on the feedback report identifiers.

22. The method of claim 21, wherein a first report from the UE includes acknowledgements for transmissions scheduled by control information messages comprising a first feedback report identifier.

23. The method of claim 22, wherein the first report includes the first feedback report identifier.

24. The method of any of claims 21-23, wherein the reported acknowledgements are hybrid automatic repeat request, HARQ, feedback.

25. The method of any of claims 21-24, wherein the network node receives a report comprising acknowledgements of reception of scheduled transmissions, and wherein the report comprises an upper time limit specifying an upper limit in time for which scheduled transmissions are acknowledged in the report.

26. The method of claim 25, wherein the report comprises a lower time limit specifying a lower limit in time for which scheduled transmissions are acknowledged in the report.

27. The method of claim 25, wherein acknowledgements for not yet acknowledged transmissions up until the upper time limit are included in the report.

28. A user equipment, UE (22), configured to communicate with a network node (16), wherein the UE is configured to: receive a plurality of control information messages scheduling respective transmissions to the UE; and report acknowledgements of reception of the scheduled transmissions, wherein the control information messages comprise feedback report identifiers indicating which of the scheduled transmissions to be acknowledged in the same report, and wherein the reporting is performed based on the feedback report identifiers.

29. The UE of claim 28, configured to perform the method of any of claims 2-20.

30. A user equipment, UE (22), configured to communicate with a network node (16), wherein the UE comprises a radio interface (46) and processing circuitry (50) configured to: receive a plurality of control information messages scheduling respective transmissions to the UE; and report acknowledgements of reception of the scheduled transmissions, wherein the control information messages comprise feedback report identifiers indicating which of the scheduled transmissions to be acknowledged in the same report, and wherein the reporting is performed based on the feedback report identifiers.

31. The UE of claim 30, wherein the radio interface and processing circuitry are configured to perform the method of any of claims 2-20.

32. A network node (16) configured to communicate with a user equipment, UE (22), wherein the network node is configured to: transmit a plurality of control information messages scheduling respective transmissions to the UE; and receive, from the UE, reporting of acknowledgements of reception of the scheduled transmissions, wherein the control information messages comprise feedback report identifiers indicating which of the scheduled transmissions to be acknowledged in the same report, and wherein the reporting is performed based on the feedback report identifiers.

33. The network node of claim 32, configured to perform the method of any of claims 22- 27.

34. A network node (16) configured to communicate with a user equipment, UE (22), wherein the network node comprises a radio interface (30) and processing circuitry (36) configured to: transmit a plurality of control information messages scheduling respective transmissions to the UE; and receive, from the UE, reporting of acknowledgements of reception of the scheduled transmissions, wherein the control information messages comprise feedback report identifiers indicating which of the scheduled transmissions to be acknowledged in the same report, and wherein the reporting is performed based on the feedback report identifiers.

35. The network node of claim 34, wherein the radio interface and the processing circuitry are configured to perform the method of any of claims 22-27.

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