HYBRID AUTOMATIC REPEAT REQUEST TRANSFER

A method (800) of transferring Hybrid Automatic Repeat Request, HARQ, positive Acknowledgement, ACK, or Negative Acknowledgement, NACK, in a wireless communication system is presented. The wireless communication system comprises a first wireless device (110), a second wireless device (120) and a network node (150). The method (800) comprises transmitting (810), by the network node (150), a first transmission (510) to the first wireless device (110). In response thereto, the first wireless device (110) transmits (820) a first HARQ-ACK/NACK (515) associated with the first transmission (510). Responsive to control information provided to the second wireless device (120) indicating that the first HARQ-ACK/NACK (515) is to be forwarded to the network node (150), the second wireless device (120) relays (830) the first HARQ-ACK/NACK (515) to the network node (150).

TECHNICAL FIELD

The present invention relates to transfer of ACK/NACK in a wireless communications network and more precisely to a method of transferring Hybrid Automatic Repeat Request, HARQ-ACK/NACK in a wireless communication system.

BACKGROUND

In modern communications system, capacity and reliability of communication is of great importance. Several methods for increased reliability are available and one such method is to use an automatic repeat request, ARQ, scheme. The ARQ scheme allows errors in received information bits to be corrected by retransmission of data. Generally, this may comprise one or several schemes of how and if a retransmission is to be performed, exemplary schemes are stop and wait, SAW, go-back-N, GBN, selective repeat, SR, etc.

In order to further increase reliability of communications, the ARQ scheme may be combined with a Forward Error Correction, FEC, scheme forming, what is commonly known as a Hybrid Automatic Repeat Request, HARQ, scheme. The FEC scheme allows incorrectly received information bits to be corrected by an added error correction code.

Generally, in an HARQ scheme, the receiving entity tries to perform error correction by means of the error correction code, and if error correction fails, a retransmission is requested by a negative acknowledge, NACK, is transmitted by the receiving entity to a transmitting entity. Upon reception of the NACK, the transmitting entity retransmits data in accordance with a HARQ mode and the receiving entity combines the retransmitted data with the previously, erroneously, received data, effectively improving the reliability of the communication. Analogously, if the reception of the information bits was successful, the receiving entity transmits a positive acknowledgement, ACK, to the transmitting entity and no retransmission is required.

In a HARQ scheme, information bits transmitted by the transmitting entity will require downlink DL capacity in the communications system for transfer, and each ACK/NACK transmitted by the receiving entities will require uplink UL capacity in the communications system. The number of UL resources for reporting ACK/NACK are limited and it may very well be that a UL link budget is worse than a corresponding DL link budget.

SUMMARY

It is in view of the above considerations and others that the various embodiments of this disclosure have been made. The present disclosure therefor recognizes the fact that there is a need for improvement of the existing art described above.

It is a general object of the embodiments described herein to provide a new type of method for transferring Hybrid Automatic Repeat Request, HARQ, positive Acknowledgement, ACK, or Negative Acknowledgement, NACK, in a wireless communication system which is improved over the prior art and which eliminates or at least mitigates one or more of the drawbacks discussed above. More specifically, an object of the embodiments discussed in this disclosure is to provide a method that enables L1 relaying.

In a first aspect, a method of transferring Hybrid Automatic Repeat Request, HARQ, positive Acknowledgement, ACK, or Negative Acknowledgement, NACK, in a wireless communication system is presented. The wireless communication system comprises a first wireless device, a second wireless device and a network node. The method comprises the network node transmitting a first transmission to the first wireless device. The first wireless device transmits, in response thereto, a first HARQ-ACK/NACK associated with the first transmission. Responsive to control information provided to the second wireless device indicating that the first HARQ-ACK/NACK is to be forwarded to the network node, the second wireless device relays the first HARQ-ACK/NACK to the network node.

In one variant, the first transmission is transmitted directly to the first wireless device. This is beneficial as it enables the relaying to be implemented selectively in the UL without affecting DL.

In one variant, the first wireless device determines if the first HARQ-ACK/NACK should be relayed by the second wireless device based on at least one of an uplink, UL, channel quality of the first wireless device, an UL channel resource availability of the first wireless device, an UL channel capacity of the first wireless device, and/or an urgency associated with the first HARQ-ACK/NACK. This is beneficial as the first wireless device may itself decide if the first HARQ-ACK/NACK should be relayed or not.

In one variant, the network node determines if the first HARQ-ACK/NACK should be relayed by the second wireless device based on at least one of an uplink, UL, channel quality of the first wireless device and/or the second wireless device, an UL channel resource availability of the first wireless device and/or the second wireless device, an UL channel capacity of the first wireless device and/or the second wireless device, and/or an urgency associated with the first HARQ-ACK/NACK. This is beneficial as the network node may itself decide if the first HARQ-ACK/NACK should be relayed or not.

In one variant, the first HARQ-ACK/NACK is transmitted across a sidelink responsive to that the first HARQ-ACK/NACK is to be relayed by the second wireless device. This is beneficial as the sidelink communication will not load the main UL/DL links and is extra beneficial if UL resources are scarce.

In one variant, the sidelink is one or more of a Physical Sidelink Feedback Channel, PSFCH, a Physical Sidelink Shared Channel, PSSCH, a Physical Sidelink Control Channel, PSCCH, a non-cellular communications link, a channel enabling physical layer decoding of HARQ-ACK/NACK, and/or a channel enabling higher-layer decoding of HARQ-ACK/NACK. This is beneficial as the sidelink communication will not load the main UL/DL links and is extra beneficial if UL resources are scarce.

In one variant the sidelink is selected by the first wireless device based on allocated resources provided by the network node. This is beneficial as the sidelink communication will not load the main UL/DL links and is extra beneficial if UL resources are scarce.

In one variant the sidelink is assigned by the network node (150). This is beneficial as the sidelink communication will not load the main UL/DL links and is extra beneficial if UL resources are scarce.

In one variant, the control information is provided to the first wireless device at least by the network node. This is beneficial as the network node possesses knowledge of network parameters that may be pertinent to the decision of relaying or not.

In one variant, the control information is provided to the second wireless device at least as an indication comprised in the first HARQ-ACK/NACK associated with first transmission. This is beneficial as it allows the decision to relay to be taken per HARQ-ACK/NACK.

In one variant, the wireless communication system further comprises one or more additional wireless devices. The method further comprises the network node transmitting an additional transmission to one of the one or more additional wireless devices. In response thereto, said one of the one or more additional wireless devices transmits an additional HARQ-ACK/NACK associated with the additional transmission. Responsive to control information provided to the second wireless device indicating that the additional HARQ-ACK/NACK and the first HARQ-ACK/NACK is to be forwarded to the network node, the second wireless device relays the first HARQ-ACK/NACK together with the additional HARQ-ACK/NACK to the network node. This is beneficial as several relayed HARQ-ACK/NACKs may be transmitted at the same time.

In one variant, the method further comprises the network node transmitting a second transmission to the second wireless device. The step of relaying further comprises relaying, by the second wireless device, a second HARQ-ACK/NACK associated with second transmission together with any other HARQ-ACK/NACK that are to be relayed to the network node (150). This is beneficial as the combination of several HARQ-ACK/NACK will reduce the signaling overhead and network load.

In one variant, the step of relaying comprises combining the first HARQ-ACK/NACK with any other HARQ-ACK/NACK that are to be relayed to the network node to provide a combined HARQ-ACK/NACK. The second wireless device relays the combined HARQ-ACK/NACK to the network node. This is beneficial as the combination of several HARQ-ACK/NACK will reduce the signaling overhead and network load.

In one variant, wherein at least one of the first transmission, the second transmission and/or the additional transmission are sent at different timeslots of a codebook. The HARQ-ACKs/NACKs associated with the transmissions that are sent at different timeslots and relayed by the second wireless device, are coded in one single line of the codebook. This is beneficial as the codebook size is reduced and thereby signaling overhead.

In one variant, wherein at least one of the first transmission, the second transmission and/or the additional transmission are sent at overlapping timeslots of the codebook, the HARQ-ACKs/NACKs associated with the transmissions sent at overlapping timeslots and relayed by the second wireless device, are coded on separate lines of the codebook, wherein each separate line is associated with a respective wireless device. This is beneficial as it allows a clear and straight forward association between a common codebook and the associated wireless devices.

In one variant only a HARQ-ACK is relayed. This is beneficial as it reduces network and signaling load.

In a second aspect, a first wireless device comprising one or more controllers is presented. Said one or more controllers are configured to, when the first wireless device is operable in a wireless communication system, perform the steps associated with first wireless device of the method according to the first aspect.

In a third aspect, a second wireless device comprising one or more controllers is presented. Said one or more controller are configured to, when the second wireless device is operable in a wireless communication system, perform the steps associated with second wireless device of the method according to the first aspect.

In a fourth aspect, an additional wireless device comprising one or more controllers is presented. Said one or more controllers are configured to, when the additional wireless device is operable in a wireless communication system, perform the steps associated with the additional wireless device of the method according to the first aspect.

In a fifth aspect, a network node comprising one or more controllers is presented. Said one or more controllers are configured to, when the network node is operable in a wireless communication system, perform the steps associated with network node of the method according to the first aspect.

In a sixth aspect, a wireless communication system comprising a first wireless device according to the second aspect, a second wireless device according to the third aspect and a network node according the fifth aspect.

In one variant, the wireless communication system further comprises an additional wireless device according to the fifth aspect.

DETAILED DESCRIPTION OF EMBODIMENTS

Hereinafter, certain embodiments will be described more fully with reference to the accompanying drawings. The invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided by way of example so that this disclosure will be thorough and complete, and will fully convey the scope of the invention, such as it is defined in the appended claims, to those skilled in the art.

The term “coupled” is defined as connected, although not necessarily directly, and not necessarily mechanically. Two or more items that are “coupled” may be integral with each other. The terms “a” and “an” are defined as one or more unless this disclosure explicitly requires otherwise. The terms “substantially,” “approximately,” and “about” are defined as largely, but not necessarily wholly what is specified, as understood by a person of ordinary skill in the art. The terms “comprise” (and any form of comprise, such as “comprises” and “comprising”), “have” (and any form of have, such as “has” and “having”), “include” (and any form of include, such as “includes” and “including”) and “contain” (and any form of contain, such as “contains” and “containing”) are open-ended linking verbs. As a result, a method that “comprises,” “has,” “includes” or “contains” one or more steps possesses those one or more steps, but is not limited to possessing only those one or more steps.

Regarding scenarios and embodiments presented throughout this disclosure, albeit presented in specific terms, it should be understood that any specific terms may, unless otherwise is clearly stated, very well be replaced by more general, generic terms even if not explicitly specified. For example, the mentioning of specific signaling and control channel relating to e.g. specific cellular standards should be considered examples and this disclosure is, as the skilled person will appreciate after digesting the teachings herein, applicable to any suitable communication system, wireless or wired.

As mentioned earlier, the number of UL resources for reporting positive acknowledgement, ACK or negative acknowledgement, NACK, are limited and it may very well be that an uplink, UL, link budget is worse than a corresponding downlink, DL, link budget. This means that scenarios exist, wherein a wireless device, such as a User Equipment, UE, is unable to transmit an ACK/NACK to a network node. It may be that the capacity of a channel for transmitting ACK/NACK is limited or that frequency selective fading causes imbalance in the link budgets. Based on these findings, the inventors behind this disclosure have devised a method for improving the transmission of hybrid automatic repeat request, HARQ, in a wireless communication system. As will be clear to the person skilled in the art after digestion of the teachings of the present disclosure, the presented embodiments will e.g. reduce the risk of interferences between wireless devices, when e.g. one wireless device is at a location with poor signaling conditions, no additional latency is introduced as the case with e.g. Physical Uplink Control Channel, PUCCH, repetition, the required PUCCH resources are reduced increasing capacity of the wireless communication system and reduced and reduce the risk of HARQ ACK/NACK transmission errors.

With reference toFIG.1, a wireless communication system10according to an embodiment will be introduced. The wireless communication system10comprises a first wireless device110, a second wireless device120and a network node150. The first wireless device110and the second wireless device120are in wireless communication with the network node150. The network node150is configured to send transmissions to the first wireless device110and the second wireless device120. Responsive thereto, the first wireless device110and the second wireless device120are configured to transmit an ACK or NACK to the network node150indicating a successful or unsuccessful reception of the transmission from the network node150by the respective wireless device110,120. In addition to the, the wireless communication system10may further comprise one or more additional wireless devices130. Said one or more additional wireless devices130are in wireless communication with the network node150. The network node150is configured to send transmissions to said one or more additional wireless devices130. Responsive thereto, said one or more additional wireless devices130are configured to transmit an ACK or NACK to the network node150indicating a successful or unsuccessful reception of the transmission from the network node150by the respective additional wireless devices130. In addition to being in communication with the network node150, the wireless devices110,120,130may be in direct wireless communication with each other through a sidelink15. In the wireless communication system10ofFIG.1, the first wireless device110and the second wireless device120are in communication across a sidelink15.

The following sections provide a brief introduction to the concept and configuration of silenlink communication. The sidelink15may, in e.g. New Radio, NR devices be scheduled either by the network node150, gNB, referred to as Mode 1, or autonomously by the wireless device110,120,130, Mode 2. In Mode 2, the wireless device110,120,130selects sidelink resources from a (pre-)configured sidelink resource pool(s) based on a channel sensing mechanism. For the wireless devices110,120,130within coverage of a network node150, the network node150may be configured to adopt Mode 1 or Mode 2. For wireless devices out-of-coverage, only Mode 2 can be adopted. For NR sidelink transmissions, at most one sidelink bandwidth part, BWP, may be configured on a carrier, and the minimum unit for resource scheduling in the frequency domain is a subchannel. Wherein a subchannel is composed of 10, 15, 20, 25, 50, 75, or 100 consecutive resource bocks, RBs, depending on practical configuration.

The sidelink15may be utilized as a layer 2 resource, which allows one wireless device110,120,130to relay data, generally a Protocol Data Unit, PDU, received from another wireless device110,120,130across the sidelink15. The methodology of using the sidelink15for relaying a PDU is described in e.g. 3GPP TR 23.733 V15.1.0.

For a NR wireless device, the sidelink15comprises a number of physical channels, a Physical Sidelink Control Channel, PSCCH, carrying control information in the sidelink; a Physical Sidelink Shared Channel, PSSCH, carrying a data payload, PDU, in the sidelink and additional control information; a Physical Sidelink Broadcast Channel, PSBCH, carrying information for supporting synchronization in the sidelink15; and a Physical Sidelink Feedback Channel, PSFCH, carrying feedback related to the successful or failed reception of a sidelink transmission. The PSFCH is transmitted by a sidelink receiving wireless device110,120,130for unicast and groupcast, which conveys 1-bit information over 1 RB for the HARQ-ACK and the HARQ-NACK. In addition, channel state information, CSI, is carried in the medium access control, MAC, control element, CE, over the PSSCH instead of the PSFCH. In the time domain, a time gap between the PSSCH and the PSFCH is configured. However, when a receiving wireless device110,120,130sends the HARQ ACK/NACK on the PSFCH, only the transmitting wireless device110,120,130has the capability to receive such ACK/NACK messages, and a network node150cannot receive this feedback transmission. Consequently, a network node150may not know whether to further allocate resources for a transmitting wireless device110,120,130to retransmit a transport block, TB, or not. To obtain resources of the PSSCH for subsequent retransmissions, a transmitting wireless device needs to forward the sidelink HARQ ACK/NACK message to a network node when a feedback message is received on the PSFCH. To further obtain resources for a transmitting wireless device to send the sidelink HARQ ACK/NACK to a network node150, the network node150may allocate one physical uplink control channel, PUCCH, occurring after the last resource in the PSSCH set for initial sidelink transmissions. When a NACK is received by a network node150, the network node150further allocates PSCCH and PSSCH resources for sidelink retransmissions, and this resource allocation is indicated in a Downlink Control Information, DCI, field in the case of dynamic grant. Alternatively, a transmitting wireless device110,120,130may launch the TB retransmission through the reserved PSCCH and the PSSCH in a case of a configured grant. In the Mode 2 resource allocation, when traffic arrives at a transmitting wireless device110,120,130, this transmitting wireless device110,120,130is configured to autonomously select resources for the PSCCH and the PSSCH. To further minimize the latency of the feedback HARQ ACK/NACK transmissions and subsequently retransmissions, a transmitting wireless device110,120,130may also reserve resources for PSCCH/PSSCH for retransmissions.

The following sections provide a brief introduction to the concept and configuration of cellular transmissions, typically for NR devices. In NR, there are three types of HARQ-ACK code construction in NR, semi-static code construction, Type 1, dynamic code construction, Type 2, and one-shot feedback, Type 3. The latter was introduced in 3GPP Rel-16 for NR-U, in Rel-17 for NR. The general procedure for receiving downlink, DL, transmission is that the wireless device110,120,130monitors and decodes a Physical Downlink Control Channel, PDCCH, in slot n which points to a DL data scheduled in slot n+K0, wherein K0is larger than or equal to zero. The wireless device110,120,130then decodes the data in the corresponding Physical Downlink Shared Channel, PDSCH. Finally, based on the outcome of the decoding the wireless device110,120,130sends an ACK of a correct decoding or a NACK of an incorrect decoding to the network node150at time slot n+k0+k1, in case of slot aggregation, n+K0would be replaced by the slot where the associated PDSCH ends. Both of K0and k1are indicated in the DCI. The resources for sending the acknowledgement are indicated by a Physical Uplink Control Channel, PUCCH, resource indicator, PRI, field in the DCI which points to one of PUCCH resources that are configured by higher layers.

Depending on e.g. a DL/UL slot configurations, or whether carrier aggregation or per code-block group, CBG, transmission is used in the DL, the feedback for several PDSCHs may need to be multiplexed in one single feedback. Generally, this is done by constructing HARQ-ACK codebooks. In NR, the wireless device110,120,130may be configured to multiplex the ACK/NACK bits using a semi-static codebook or a dynamic codebook.

Semi-static HARQ codebook, or Type 1 codebook, comprises a bit sequence where each element contains an ACK/NACK bit from a possible allocation in a certain slot, carrier, or TB. When the wireless device110,120,130is configured with a CBG and/or a time-domain resource allocation, TDRA, table with multiple entries; multiple bits are generated per slot and TB. It should be mentioned that the codebook is generally derived regardless of the actual PDSCH scheduling. The size and format of the semi-static codebook is generally preconfigured based on the mentioned parameters. The drawback of semi-static HARQ ACK codebook is that the size is fixed, and regardless of whether there is a transmission or not, a bit is reserved in the feedback matrix. In scenarios where the wireless device110,120,130has a TDRA table with multiple time-domain resource allocation entries configured; the table is pruned, i.e. entries are removed based on a specified algorithm in order to derive a TDRA table that only contains non-overlapping time-domain allocations. One bit is then reserved in the HARQ CB for each non-overlapping entry, that is assuming the wireless device110,120,130is capable of supporting reception of multiple PDSCH in a slot.

In the dynamic HARQ codebook, or type 2 codebook, an ACK/NACK bit is present in a codebook only if there is a corresponding transmission scheduled. To avoid any confusion between the network node150and the wireless device110,120,130on the number of PDSCHs that the wireless device110,120,130is expected to send a feedback for, a counter downlink assignment indicator, DAI, field is available in the DL assignment. The DAI field denotes accumulative number of serving cell-PDCCH occasion pairs in which a PDSCH is scheduled to a wireless device110,120,130up to the current PDCCH. In addition to this, a total DAI field is available which, when present, shows the total number of serving cell-PDCCH occasions up to, and including, all PDCCHs of a current PDCCH monitoring occasion. The timing for sending HARQ feedback is determined based on both PDSCH transmission slot with reference to PDCCH slot k0and the PUCCH slot that contains HARQ feedback k1.

Assuming there are no errors in the downlink control signaling, a dynamic codebook would be straightforward. However, in the presence of an error in the downlink control signaling, the wireless device110,120,130and the network node150may have 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. If, by means of example, a wireless device110,120,130was scheduled for downlink transmission in two subsequent slots but missed the PDCCH and thereby the scheduling assignment for the first slot. As a result, the wireless device110,120,130will only transmit an acknowledgment for the second slot. The network node150on the other hand, tries to receive acknowledgments for both slots. This leads to mismatch. In NR, one way of mitigating this mismatch is by utilization of the downlink assignment index which is included in the DCI comprising the downlink assignment. The DAI field is further split into two parts, a counter DAI, cDAI, and, in the case of e.g. carrier aggregation, a total DAI, tDAI. The cDAI included in the DCI indicates the number of scheduled downlink transmissions up to the point the DCI was received in a carrier. The tDAI 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.

As present cellular wireless networks are defined, a wireless device110,120,130may be unable to reliably send a HARQ ACK/NACK to the network node150due to poor UL channel condition. As previously indicated, this may occur in frequency division duplex, FDD, systems in case of frequency selective fading where DL channels are good, but UL channels are poor. Similarly, valid also for time division duplex, TDD, an output power of a wireless device110,120,130may be reduced due to e.g. antenna loading causing mismatch affecting a gain of a transmitter power amplifier of the wireless device110,120,130more than a corresponding gain of a receiver low noise amplifier, LNA, of the wireless device110,120,130. Also, the wireless device110,120,13may have limited power for uplink transmission, e.g., it is a permanently low power device or its power may have been temporarily reduced.

There are situations where PUCCH resources for reporting a HARQ-ACK/NACK and other signaling may be limited. This may be exemplified by a scenario wherein there are heavy downlink data-consumers and a TDD pattern is devised such that higher downlink transmissions are provided in a TDD pattern. Assume a TDD pattern is of 8 DL+1 UL slots wherein each DL slot is dedicated to one wireless device110,120,130. The wireless device110,120,130receiving data in the first DL slot, slot 0, can report in timeslot 8, while a wireless device110,120,130receiving its data in a second DL slot, slot 1, will have to wait for a next available uplink slot.

In order to enhance PUCCH coverage, a wireless device110,120,130may apply repetitions for a PUCCH transmission up to a configurable number of times, e.g., 2, 4 or 8. One drawback with PUCCH repetition is that a wireless device110,120,130experiencing poor UL coverage may create interference to the other wireless device110,120,130with good coverage. In addition to this, additional latency, e.g., with 8 times of PUCCH repetitions, may be introduced. There may also be situations where there is an obstacle between a wireless device110,120,130and its network node150. In such situations, increasing the PUCCH transmitted power or applying PUCCH repetition may not help in improving PUCCH coverage.

An alternative approach is to let a wireless device110,120,130with poor UL coverage connect to the network node via a relay wireless device110,120,130. As network relay is currently being developed, e.g. 3GPP Rel-17. Relay architectures are only feasible to enable a relaying wireless device to relay data and control signaling above L2 of a remote wireless device to the network node150. In other words, with current or planned relay architectures, it is not feasible to relay L1 signaling of a wireless device110,120,130by another wireless device110,120,130to the network node150.

The inventors behind this disclosure have realized that it would be beneficial to, in the light of the above issues, develop mechanisms to enable a relay wireless device110,120,130to relay L1 signaling of a remote wireless device110,120,130to a network node150. By configuring a wireless communications network10such that a first wireless device110receives HARQ-ACK feedbacks from a second wireless device120and optionally from one or more additional wireless devices130, the first wireless device may combine the feedback(s) of the wireless devices120,130with its own HARQ-ACK feedback and transmits the feedbacks to the network node150. This may be accomplished by configuring the first wireless device110such that it utilizes the PUCCH to sends HARQ-ACK information. However, historically, all HARQ-ACKs sent on a PUCCH by the first wireless device110would belong to the first wireless device110only. In the present disclosure, changes in PUCCH are allowed making it possible for the first wireless device to send HARQ-ACK information belonging to multiple wireless devices, including itself.

Turning now to the simplified signaling diagram ofFIG.2, four different signaling scenarios A-D will be introduced. Signals are indicated as horizontal lines, and a direction of the signals is indicated by an arrow pointing to the receiver of the signal. InFIG.2, from the right, the vertical lines illustrate the network node150, the second wireless device120, the first wireless device110and the additional wireless devices130.

In signaling scenario A ofFIG.2, the network node150sends a first transmission510to the first wireless device110. In response to the first transmission510, the first wireless device110sends a first HARQ-ACK/NACK515to the network node150. Scenario A is a typical way of signaling a HARQ-ACK/NACK in a communications network10.

In signaling scenario B ofFIG.2, the network node150still sends a first transmission510to the first wireless device110, but rather having the first wireless device110sends the first HARQ-ACK/NACK515to the network node, the first HARQ-ACK/NACK515is received by the second wireless device120which in turn sends the first HARQ-ACK/NACK515to the network node. In other words, the first HARQ-ACK/NACK515from the first wireless device110is relayed to the network node150by the second wireless device120. The wireless device110,120,130acting as a relay may, in sections of this disclosure be referenced to as a coordinator wireless device110,120,130. Any of the devices mentioned herein may be the coordinator wireless device110,120,130, but for consistency and simplicity of explanation, the second wireless device120will typically be the coordinator wireless device110,120,130relaying HARQ-ACK/NACKs515,525,535. As will be detailed elsewhere, the first wireless device may or may not be aware of the first HARQ-ACK/NACK515being relayed or not. Scenario B may be a scenario in which the first wireless device110is experiencing transmit difficulties from e.g. UL/DL link budget mismatch.

In signaling scenario C ofFIG.2, the network node150again sends a first transmission510to the first wireless device110, but in this scenario, also sends a second transmission520to the second wireless device120. The second wireless device120receives the first HARQ-ACK/NACK515from the first wireless device and combines this with a second HARQ-ACK/NACK525of the second wireless device120being in response to the second transmission520. The second wireless device120sends the combined HARQ-ACK/NACK515,525to the network node150. As in scenario B, the first HARQ-ACK/NACK515from the first wireless device110is relayed to the network node150by the second wireless device120, but in scenario C, the second wireless device120sends the first HARQ-ACK/NACK515together with the second HARQ-ACK/NACK525.

Analogously, in signaling scenario D ofFIG.2, the network node sends a first transmission510to the first wireless device, a second transmission to the second wireless device120and an additional transmission530to the additional wireless device130. In this scenario, the second wireless device120receives, from the first wireless device110a first HARQ-ACK/NACK515associated with the first transmission510and, from the additional wireless device130, an additional HARQ-ACK/NACK535associated with the additional transmission530. The second wireless device120sends its own second HARQ-ACK/NACK525associated with the second transmission520to the network node together with the first HARQ-ACK/NACK515and the additional HARQ-ACK/NACK535.

FromFIG.2, it is clear that by allowing the second wireless device120to relay HARQ-ACK/NACK515,535from other wireless devices110,130problems previously presented are solved.

The second wireless device120is preferably configured to relay HARQ-ACK/NACK515,535from the other wireless devices110,130, and as illustrated inFIG.3, the configuration of relay of HARQ-ACK/NACK515,535may be provided as control information505from the network node150and/or from the other wireless devices110,130. In embodiments wherein the control information505is provided by the network node, the control information505may be transmitted as e.g. uplink control information, UCI on the PUCCH or multiplexed with the PUSCH. When the control information505is provided by the other wireless devices110,130, it may be sent as a direct control message or preferably comprised in the HARQ-ACK/NACK515,535to be relayed. The control information505is preferably communicated across the sidelink15. When provided by the network node150, the network node150may send DCI, i.e. dynamic PDSCH grant or SPS activation DCI or new DCI, to the second wireless device120indicating that the second wireless device120is to collect HARQ-ACK/NACK from other wireless devices110,130and relay the collected HARQ-ACK/NACK to the network node150. The other wireless devices110,130may be e.g. wireless devices110,130in a proximity of the second wireless device120allowing the other wireless devices110,130to communicate with UE1 via device to device, D2D, communication technologies, e.g., the SL15. The control information505may comprise e.g. one or more flags indicating whether the HARQ-ACK/NACK of the other wireless devices110,130may be combined or not, identities of the other wireless devices110,130etc.

In order to relay HARQ-ACK/NACK515,535from the other wireless devices110,130, the second wireless device120preferably receives the HARQ-ACK/NACK515,535from the other wireless devices110,130prior to the relaying. The channel, medium or communication path across which the second wireless device120received the HARQ-ACK/NACK515,535from the other wireless devices110,130will be exemplified in the following, it should be emphasized that these are exemplary embodiments, and several others being within the scope of this disclosure may come to the mind of the skilled person after reading the following.

The HARQ-ACK/NACK515,535to be relayed may be received by the second wireless device120on the PSFCH of the SL from the first wireless device110. A modified channel over which HARQ-ACK/NACK515,535information of the first wireless device110is transmitted to the second wireless device120may be formed e.g. by adding bit(s) in the transmitted information over PSFCH indicating that the HARQ-ACK/NACK515,535feedback is related to the first wireless device110transmitted over sidelink channel.

The HARQ-ACK/NACK515,535to be relayed may be received by the second wireless device120PSSCH on the SL from the first wireless device110. The HARQ-ACK/NACK515,525information of the first wireless device110may be multiplexed with data from first wireless device110sent over PSSCH to the second wireless device.

In some embodiments, the HARQ-ACK/NACK515information of the first wireless device110may be carried by PC5-RRC, the HARQ-ACK/NACK515information of the first wireless device110may be carried by MAC CE, or the HARQ-ACK/NACK515information of the first wireless device110may be carried by control a PDU of a protocol layer such as SDAP, PDCP, RLC, or an adaption protocol layer designed for Sidelink relay.

In one embodiment, the HARQ-ACK/NACK515of the first wireless device110may be sent over PSCCH using an existing SCI format, e.g. repurpose existing fields in the SCI format, or by using a new SCI format defined for relaying HARQ-ACK/NACK515,535information of neighbor UEs.

In some embodiments, other licensed or unlicensed radio access technologies, RAT, are used e.g. Bluetooth, Zigbee, LoRa, WIFI, are used for communicating the HARQ-ACK/NACK515,535to be relayed to the second wireless device120. Any suitable protocol such as TCP/IP, proprietary protocols etc. may be utilized.

In some embodiments, a new channel may be introduced which enables physical layer decoding of HARQ-ACK/NACK515,535transmission sent from other transmitting wireless devices110,130by the receiving wireless device120, e.g. the second wireless device120. Subsequent to decoding, the receiving wireless device120may retransmit that information by optionally including its own information to the network node150.

In some embodiments, a new channel which enables higher-layer decoding of HARQ-ACK/NACK515,535transmission which are sent from other transmitting wireless devices110,130by the receiving wireless device120, e.g. the second wireless device120. Subsequent to decoding, the receiving wireless device120may retransmit that information by optionally including its own information to the network node150.

In some embodiments, for autonomous resource selection, the preferred scenario is where the network node150allocates a certain spectrum pool, carriers or resource for HARQ-ACK/NACK515,535transmission from the first wireless device110to the second wireless device120. For example, if the first wireless device110receives PDSCH from the network node150and it want sends to HARQ-ACK/NACK515to the network node150via relaying over the second wireless device120, then the first wireless device may autonomously select resources, i.e. PRBs from given spectrum pool, to transmit HARQ-ACK/NACK515codebook to the second wireless device120.

As disclosed above with some exemplifying embodiments, the second wireless device120may be provided with information regarding e.g. medium and resource allocation for relaying of HARQ-ACK/NACK515,535from other wireless devices110,130. It should be mentioned that there may be further embodiments to this, in one embodiment, the network node150informs the first wireless device110to send its HARQ-ACK/NACK515information via the second wireless device120and accordingly the network node150may be configured to assign sidelink resources for transmitting HARQ-ACK/NACK515,535feedbacks of other wireless devices110,130to the second wireless device. In another embodiment, the resources are awarded to the first wireless device110, but the decision of HARQ-ACK/NACK515information transmission is left to the first wireless device110, that is to say, resources are allocated by the network node150, but the transmission decision is autonomously made by the first wireless device110. For instance, the first wireless device may be configured such that when it is able to transmit via UL, i.e. directly to the network node150, it does so, otherwise the first wireless device110may relay the HARQ-ACK/NACK515information to the second wireless device120, e.g. if UL channel is bad. In one embodiment, the first wireless device110may be configured to transmit HARQ-ACK/NACK515on both UL and via the second wireless device120for increased reliability. This option may be useful in situations where the UL for the first wireless device110is not reliable due to e.g. rapid fluctuations, fading etc. As an additional embodiment, the first wireless device may decide to forward its HARQ-ACK/NACK515information to the second wireless device in situations when there is no available PUCCH resource or PUSCH resource to transmit the HARQ-ACK/NACK515information in the closing time while the HARQ-ACK information is delay critical e.g., for URLLC. In this situation, the HARQ-ACK/NACK515information may be relayed to the network node140via the second wireless device120in order to reduce latency.

The control information505may comprise information indicating what resources to utilize when relaying HARQ-ACK/NACK515,535from the other wireless devices110,130. In embodiments wherein the network node150allocate resources, the resources for relaying HARQ-ACK/NACK515,535may comprise, but are not limited to, HARQ-ACK/NACK resources in specific cells/carriers, HARQ-ACK/NACK resources in specific BWPs of the same serving cell where the PDSCH receptions associated with the HARQ ACK occur, HARQ-ACK/NACK resources transmission using specific Transmission Reception Points, TRPs, DCI allocated HARQ-ACK/NACK resources indicated in a specific CORESET, and/or DCI allocated HARQ-ACK/NACK resources indicated by using specific DCI format. In the exemplified embodiment, the second wireless device120may relay HARQ-ACK/NACK515,535from the other wireless devices110,130utilizing e.g. MAC CE in PUSCH using a configured grant or a dynamic grant, RRC signaling in PUSCH using a configured grant or a dynamic grant etc.

The relaying functionality may, as exemplified above, be under control of the network, e.g. the network node150or in the case of NR, a scheduler in a gNB. This allows the network node150to schedule the second wireless device to perform, or not to perform relaying based on RRC parameter or DCI parameter. In other embodiments, the network node150may permit the second wireless device120to relay only the HARQ-ACK/NACK515,535information of a permitted list of wireless devices110,130. That is to say, the second wireless device120only acts as relay for the wireless devices110,130that are specified in a list provided by the network node150. The list of wireless devices110,130where relaying is permitted may be provided to the second wireless device by RRC parameter or DCI parameter. The list of wireless devices110,130where relaying is permitted may be comprised in the control information505. In another embodiment, the network node150may permit the second wireless device to relay HARQ-ACK/NACK515,535information for specific services. For example, the relaying of only HARQ-ACK information of URLLC services is allowed but not eMBB or CMTC services. As the skilled person appreciates, the above listed embodiments are in no way strict alternatives but may be freely combined and the network node150may be configured to permit the second wireless device120to relay any combination of the above examples. For example, the relying of URLLC services of a permitted list of wireless devices110,130is one workable embodiment.

In some embodiments, a wireless device110,120,130, i.e. the first wireless device110or the additional wireless device130from the non-limiting examples of this disclosure, may under some conditions be configured to send HARQ-ACK/NNACK515,535feedback on the UL and in under other conditions via relaying. UL transmission may be utilized when e.g. when a UL radio quality is above a UL quality threshold and relaying, relaying via the second wireless device120, over SL when the UL radio quality is below the UL quality threshold. One advantage of this is that the delay is reduced if the direct HARQ-ACK/NACK515,535feedback over UL is successful, compared to if only the relayed feedback is successful as there is generally an added delay when relaying. In this case one further embodiment, the first wireless device110is configured with two k1 values in DCI, e.g., the first k1 value is used to indicate the offset from PDSCH transmission to the direct HARQ feedback transmission over UL resource. The second k1 value is the offset from the PDSCH transmission to the relayed HARQ feedback transmitted/relayed to the second wireless device120over SL resource. In alternative embodiment, there is one k1 value in DCI, either it is used to transmit e.g. feedback in UL or transmit feedback over SL to the second wireless device120.

In one embodiment, the relay selection/reselection may occur independent of the first wireless device110needs to transmit/relay its HARQ-ACK/NACK515information. Due to e.g. the first wireless device110being mobile or varying channel conditions, a new coordinator wireless device120,130for relaying may be selected based on parameters such as signal strength, path loss, etc. for the first wireless device's L1 HARQ-ACK/NACK515information relaying capabilities. When a new coordinator wireless device is selected, and if there is a need to transmit HARQ-ACK/NACK515,525,535information, then first wireless device may be configured to send it via the new coordinator wireless device instead of via the old coordinator wireless device120, the second wireless device. In other words, the second wireless device120is replaced by new coordinator wireless device for relaying the first wireless device's L1 HARQ-ACK information. This means that the first wireless device110continually/semi-persistently e.g. after every N slots/time units, scan the received signal strength from the neighboring wireless devices120,130and the network node150to determine/select the best node to receive its UL transmission directly, which may be a wireless device, acting as a coordinator wireless device, or the network node150. Alternatively, the first wireless device may be configured to trigger a relay selection/reselection when a current sidelink15between the first wireless device110and the second wireless device120has channel quality below a configured sideling quality threshold e.g. for a configured time period.

In one embodiment, a group of wireless devices110,130is determined. The group of wireless devices110,130is configured to transmit their HARQ-ACK515,535information via the coordinator wireless device120. The network node150may be configured to group wireless devices110,120,130based on one or more conditions where one condition may relate to a path loss between wireless devices e.g., the path loss between a wireless device110,120,130, and the coordinator wireless device120. If this path loss is below a path loss threshold, the wireless device110,120,130may be added to the group of wireless devices110,120,130. Another condition may relate to a channel quality, e.g. if UL channel, over which HARQ-ACK CB is supposed to be transmitted is poor, then a nearby wireless device is chosen as coordinator wireless device so that the coordinator wireless device may relay the HARQ-ACK/NACK information of the wireless device suffering from poor UL. The channel quality may be measured and analyzed using indicators such UL signal strength and quality, RSRP, RSRQ, CSI report, etc. Another condition may relate to applications, services and/or traffic types. Wireless devices110,120,130may be grouped in case they have similar/same application, service, or traffic type as these may imply that they have similar traffic pattern and/or QoS requirements.

In one embodiment, the coordinator wireless device120combines HARQ-ACK/NACK of itself and at least one other wireless device110,130based on a priority of the HARQ-ACK/NACK. Combination of feedback may, in this embodiment be considered if the HARQ-ACK/NACK515,525of both wireless devices110,120belongs to same priority, if the HARQ-ACK/NACK515,525of both wireless devices110,120belongs to mix of priority. The mix of priority may be exemplified by the coordinator wireless device having high priority HARQ-ACK/NACK525, and the first wireless device110has low priority HARQ-ACK/NACK515, or if both the coordinator wireless device120and the first wireless device110has a mix of high and low priority HARQ-ACK/NACK515,525.

Albeit this disclosure mainly focuses on relaying of HARQ-ACK and HARQ-NACK, it should be emphasized that in embodiments, it is possible that either the coordinator wireless device120or any of the wireless devices110,130whose information is to be forwarded, may be configured to only relay a HARQ-ACK or a HARQ-NACK. For the wireless devices110,130whose information is to be forwarded, this will reduce the signaling required between the coordinator wireless device120and the wireless devices110,130whose information is to be forwarded, thereby saving power and reducing spectrum load. Where coordinator wireless device120is configured to only forward HARQ-ACK, this also reduces power consumption and spectrum load and is further beneficial as the network node150may be configured to retransmit a PDSCH if an associated HARQ-ACK is not received within a predetermined time period from the initial transmission of the PDSCH.

It should be mentioned that in some embodiments, whether HARQ-ACK information of e.g. the first wireless device110can be relayed via a neighboring wireless device, e.g. the second wireless device120, may be configurable per service, traffic type, LCH or LCG. This means that the first wireless device110would only forward the HARQ-ACK associated with specific services, traffic types, LCHs or LCGs, which may be associated with specific Quality of Service, QOS, requirements. As a further embodiment, a first capability bit is defined. The first capability bit indicate whether an associated wireless device110,120,130supports to forward its HARQ-ACK information to the coordinator wireless device. As a further embodiment, a second capability bit is defined, indicating whether the associated wireless device110,120,130may be configured to work as coordinator wireless device for other wireless devices.

In one embodiment, DL DCI, e.g. DCI format 1_1, received by a wireless device110,120,130includes a field indicating whether the HARQ ACK timing indicator K1 in the DCI refers to the wireless device110,120,130from which the DL DCI was received, or to another wireless device110,120,130. In case K1 refers to another wireless device110,120,130, an ID of the wireless device110,120,130referred to may also be carried in the DCI.

In the following sections, exemplifying embodiments of how a coordinator wireless device120may configure a transmission of HARQ-ACK/NACK when relaying HARQ-ACK/NACK from other wireless devices110,120.

With reference toFIGS.4a-c, one embodiment of HARQ-ACK/NACK515,525,535slot configuration will be described exemplified with the first transmissions510and the second transmission520as previously introduced. The HARQ-ACK/NACK feedback transmissions515,525of the first wireless device110and the second wireless device120are configured such that their DL HARQ processes do not overlap in the time-domain. InFIG.4a, four slots S1-S4 are illustrated out of which the second transmissions520are present in a first slot S1 and a third slot S3. InFIG.4b, which illustrate the same four slots S1-S4 asFIG.4a, the first transmission510is present in a second slot S2. With this, the Type 1 CB construction for the feedback associated with multiple PDSCHs of multiple wireless devices may be configured as illustrated inFIG.4c. The PDSCHs of the two wireless devices110,120do not overlap, hence, in the CB construction, the HARQ-ACK/NACK feedback of the first wireless device110and the second wireless device120are combined in one row of HARQ-ACK/NACK codebook. As seen in a codebook300illustrated inFIG.4c, the first wireless device110and the second wireless120device have been configured with one TDRA entry in a slot. The second wireless device120is allocated with two transmissions in the first slot S1 and the third slot S3, respectively with k1=8 and k1=6. The second wireless device120has been configured with a transmission in the second slot S2 with k1=7.

As illustrated inFIG.5, the codebook300may be transmitted by the coordinator wireless device120at a next available UL slot. In one embodiment, the UL slot for transmission of the codebook300is a slot following an eighth DL slot S8.

In one embodiment, illustrated inFIGS.6a-c, multiple PDSCHs allocations for different wireless devices overlap in time-domain. Therefore, in this case, HARQ-ACK/NACK information for different wireless devices cannot be transmitted as exemplified with reference toFIGS.4a-c. As seen inFIGS.6aand6b, the first wireless device110and the second wireless device have the same configured TDRA entries in a slot or a time window, both wireless devices110,120have transmissions scheduled in the first slot S1, with k1=8, and the second wireless device120also have transmission scheduled in the third slot S3, with k1=6. In this embodiment, the coordinator wireless device120constructs CB300where HARQ-ACK information of both the first wireless device110and the second wireless device in one codebook300are mapped to two rows, each of which representing HARQ-ACK/NACK information of a wireless device. In a further embodiment, the coordinator wireless device120is configured to indicate an ID of a wireless device110,120for each row of the CB300. In order to reduce the size of the codebook300, the indicated ID may be a relative index, e.g. if the first wireless device110and the second wireless device120forms a group to help each other for relaying HARQ-ACK/NACK; a single bit field with value may indicate each wireless device110,120. For multiple wireless devices110,120,130in a group, a bitmap field may be introduced to indicate wireless devices110,120,130in the group. In an additional or alternative embodiment, the network node150has prior knowledge of which row is associated with which wireless device110,120.

As further embodiments to the CB300embodiments above, there may be scenarios, as illustrated inFIGS.7a-cwhere different wireless devices110,120,130are configured with different TDRA entries which may result in different number of HARQ-ACK/NACK bits for different wireless devices, seeFIGS.7a-b. These scenarios it may be beneficial to further extend the codebook300by adding columns to correspond to the largest number of bits of each wireless device,FIG.7c.

Additionally or alternatively, the codebook300may be constructed based on HARQ-ACK/NACK priority.

In embodiments wherein a type 2 codebook300is utilized, the coordinator wireless device may be configured to construct a type 2 CB which contains HARQ-ACK/NACK information of itself any additional wireless device110,120,130from which a HARQ-ACK/NACK is to be relayed. For type 2 CB construction, the coordinator wireless device120preferably has knowledge of the number of transmissions510,520,530itself and the additional wireless devices110,120,130are allocated with. This may be accomplished by the coordinator wireless device having knowledge related to the tDAI of the additional wireless devices110,120,130.

For simplified explanation, CDAI,UE1indicates the number of scheduled transmissions for the coordinator wireless device120up to a time at which the DCI to the coordinator wireless device is received; tDAI,UE1indicates the total number of transmissions for all carriers of the coordinator wireless device120up to this point in time, and tDAI,UE2indicates the total number of transmissions for all carriers of the first wireless device110up to this point in time. As mention, in order to construct Type 2 CB300, the coordinator wireless device120preferably knows about the total number of transmission in the first wireless device110.

In one embodiment of type 2 codebook300, in DCI, DAI counters are set by the network node150as {CDAI,UE1, tDAI,UE1+tDAI,UE} which are sent to the coordinator wireless device120and as {CDAI,UE2, tDAI,UE2} which are sent to the first wireless device110. The counters tDAI,UE1+tDAI,UE2indicate the total number of allocated transmissions across all carriers of the first wireless device110and the coordinator wireless device120up to this point in time. Next, if the first wireless device110transmits its HARQ-ACK information, Type 2 CB300of the first wireless device110, to the coordinator wireless device120over SL, and in addition, the coordinator wireless device120has knowledge of the total DAI, i.e. tDAI,UE1+tDAI,UE2, e.g. as indicated in the PDSCH allocation's DCI of the coordinator wireless device120or sent in some DCI. Consequently, the coordinator wireless device120can transmit NACK for non-reported transmissions by the first wireless device or the coordinator wireless device120. In another embodiment, similar to the one above, instead of total DAI as tDAI,UE1+tDAI,UE2, the network node150may be configured to indicate total DAIs separately, where the DAI counters are set as {CDAI,UE1, tDAI,UE1, tDAI,UE2} which are sent to the coordinator wireless device110and as {CDAI,UE2, tDAI,UE2} which is sent to the first wireless device110.

In another embodiment, the first wireless device110sends its CB300, which may be Type-1, Type-2 or one-shot to the coordinator wireless device120. The coordinator wireless device120attaches/concatenates its Type 2 CB300to the received CB300of the first wireless device110and transmits this bigger sized CB300to the network node150. If the network node150possesses knowledge of how these two codebooks300are attached, then there is no need to add the IDs of the wireless devices110,120as key to the bigger sized CB300. Otherwise, the coordinator wireless device120preferably adds the IDs of the wireless devices110,120at relevant places of the CB300, e.g. at the starting of each wireless device's codebook300.

The teachings herein are workable also when one-shot codebook is utilized. In one such embodiment, an enhancement of a one-shot codebook300s transmitted by the coordinator wireless device120to the network node150wherein the codebook300contains the HARQ-ACK information of both the coordinator wireless device120and the first wireless device110for all HARQ processes. This may be exemplified in two embodiments.

In one embodiment, the HARQ process IDs, PIDs, are not shared. For example, per carrier, each UE may be allocated maximum 16 HARQ processes, then the coordinator wireless device120comprises HARQ-ACK information for all 16 HARQ processes of the coordinator wireless device120and the first wireless device in the CB300. Consequently, the first wireless device110is preferably configured to provide the coordinator wireless device120with HARQ-ACK information of all its16or active HARQ processes. The coordinator wireless device120may be configured to assume NACK for any HARQ processes which the first wireless device did not provide. The codebook may be formed as [{UE #1-ID} {PID0-A/N, . . . , PID16-A/N}, {UE #2-ID} {PID0-A/N, . . . , PID16-A/N}].

In another embodiment, the HARQ processes are shared between the coordinator wireless device120and the first wireless device. In this embodiment, the coordinator wireless device120is preferably configured to transmit HARQ-ACK information of only 16 HARQ processes. For example, out of 16 per CB300, the first 4 HARQ processes may be allocated to the coordinator wireless device120and the last 12 HARQ processes may be allocated to the first wireless device, then the CB300may be formed as [{PID0-A/N, . . . , PID16-A/N}].

Based the teachings of the present disclosure, a method of transferring HARQ-ACK/NACK800will be presented with reference toFIGS.8aand8b. The method800is preferably adapted for use in a wireless communication system10, but may in fact be used in any type of communication system.FIG.8ais a schematic overview of the method800andFIG.8bis a signaling overview similar to that ofFIG.2but with the corresponding method steps illustrated. The method800may be performed in a wireless communication system10comprising a network node150, a first wireless device110and a second wireless device120. These devices110,120,150may be any according to any embodiment of this disclosure. The network node150transmits810a first transmission510to the first wireless device110. As a response to the transmitted810first transmission510, the first wireless device110transmits820a first HARQ-ACK/NACK515which is associated with the first transmission510. The second wireless device120is provided with control information505indicating that the second wireless device120is to forward HARQ-ACK/NACK515from at least the first wireless device110to the network node150. Based on the control information505, the second wireless device120relays830the first HARQ-ACK/NACK515, which was received from the first wireless device110, to the network node150.

The control information505may be provided to the second wireless device120by any means available, and preferably by the means presented in this disclosure. The first HARQ-ACK/NACK515, the HARQ-ACK/NACK515associated with the first transmission510, may be sent to the second wireless device120by any means available, and preferably by the means presented in this disclosure.

The first transmission510may be transmitted810in a relayed signal path from the network node150to the first wireless device110. In a preferred embodiment of the method800, the first transmission510is transmitted810directly from the network node150to the first wireless device110.

The final decision to actually relay830the first HARQ-ACK/NACK515by the second wireless device120may, as detailed elsewhere in this disclosure, be taken by e.g. the network node150, the first wireless device110, or the second wireless device120. If, for instance, the first wireless device takes the decision to relay830the first HARQ-ACK/NACK, or any HARQ-ACK/NACK for that matter, may be based on e.g. an UL channel quality of the first wireless device110, an UL channel resource availability of the first wireless device110, an UL channel capacity of the first wireless device110, and/or an urgency associated with the first HARQ-ACK/NACK515etc. Similarly, if the decision lies with the network node150, the criteria may comprise the same basis as those listed above, but preferably with the addition of the corresponding basis relating to the second wireless device120.

As explained, the teachings of this disclosure are workable also for relaying830HARQ-ACK/NACK information from more than one wireless device110,130. This means that the method800may further comprise the network node150transmitting813an additional transmission530to one of the one or more additional wireless devices130of the wireless communication network10. These additional wireless devices130are preferably configured to transmit823an additional HARQ-ACK/NACK535associated with the additional transmission530. As previously explained, based on the control information505, the second wireless device120relays830the first HARQ-ACK/NACK515together with the additional HARQ-ACK/NACK535to the network node150.

The method800may further comprise a second transmission520being transmitted812by the network node150to the second wireless device120. The second wireless device120may be configured to combine its own HARQ-ACK/NACK525associated with the second transmission520in the relaying830of other HARQ-ACK/NACK515,525.

InFIG.9a, a schematic view of the first wireless device110according to one embodiment is shown. The first wireless device110comprises one or more controllers115which may be configured to, when the first wireless device110is operable in a wireless communication system10, perform the steps associated with first wireless device110of the method800according to this disclosure.

FIG.9billustrates another example implementation of the first wireless device110, which may be in the form of a UE. The first wireless device110comprises a processor111, a memory112and a communications interface113with transmission and reception capabilities. The memory112comprises instructions executable by the processor111whereby the first wireless device110is operative to, see e.g.FIGS.8a-b, receive the first transmission510, and responsive thereto, transmit820the first HARQ-ACK/NACK515to the second wireless device120. To this end, said memory112comprising instructions executable by the processor111whereby the first wireless device110is operative to perform the steps of the method800relating to the first wireless device110as described in conjunction withFIGS.8aand8b.

FIG.9cis a schematic view of a computer program product710according to one embodiment. The computer program product710comprises instructions which, when executed on at least one processor111or controller115of the first wireless device110, cause the at least one processor110or controller115to carry out the method800and/or any other features listed in this disclosure related to the first wireless device110.

InFIG.10a, a schematic view of the second wireless device120according to one embodiment is shown. The second wireless device120comprises one or more controllers125which may be configured to, when the second wireless device120is operable in a wireless communication system10, perform the steps associated with second wireless device120of the method800according to this disclosure.

FIG.10billustrates another example implementation of the second wireless device120, which may be in the form of a UE. The second wireless device120comprises a processor121, a memory122and a communications interface123with transmission and reception capabilities. The memory122comprises instructions executable by the processor121whereby the second wireless device120is operative to, see e.g.FIGS.8a-b, receive the first HARQ-ACK/NACK51, and responsive to control information505to that effect, relay830the first HARQ-ACK/NACK515to the network node150. To this end, said memory122comprising instructions executable by the processor121whereby the second wireless device120is operative to perform the steps of the method800relating to the second wireless device120as described in conjunction withFIGS.8aand8b.

FIG.10cis a schematic view of a computer program product720according to one embodiment. The computer program product710comprises instructions which, when executed on at least one processor121or controller125of the second wireless device120, cause the at least one processor120or controller125to carry out the method800and/or any other features listed in this disclosure related to the second wireless device120.

InFIG.11a, a schematic view of the additional wireless device130according to one embodiment is shown. The additional wireless device130comprises one or more controllers135which may be configured to, when the additional wireless device130is operable in a wireless communication system10, perform the steps associated with additional wireless device130of the method800according to this disclosure.

FIG.11billustrates another example implementation of the additional wireless device130, which may be in the form of a UE. The additional wireless device130comprises a processor131, a memory132and a communications interface133with transmission and reception capabilities. The memory132comprises instructions executable by the processor131whereby the additional wireless device130is operative to, see e.g.FIGS.8a-b, receive the additional transmission530, and responsive thereto, transmit823the additional HARQ-ACK/NACK535to the second wireless device120. To this end, said memory132comprising instructions executable by the processor131whereby the additional wireless device130is operative to perform the steps of the method800relating to the additional wireless device130as described in conjunction withFIGS.8aand8b.

FIG.11cis a schematic view of a computer program product730according to one embodiment. The computer program product730comprises instructions which, when executed on at least one processor131or controller135of the additional wireless device130, cause the at least one processor130or controller135to carry out the method800and/or any other features listed in this disclosure related to the additional wireless device110.

InFIG.12a, a schematic view of the network node150according to one embodiment is shown. The network node150comprises one or more controllers155which may be configured to, when network node150is operable in a wireless communication system10, perform the steps associated with network node150of the method800according to this disclosure.

FIG.12billustrates another example implementation of the network node150, which may be in the form of a gNB. The network node150comprises a processor151, a memory152and a communications interface153with transmission and reception capabilities. The memory152comprises instructions executable by the processor151whereby the network node150is operative to, see e.g.FIGS.8a-b, transmit810the first transmission510to the first wireless device110, receive, in responsive thereto receive the first HARQ-ACK/NACK515relayed830by the second wireless device120. To this end, said memory152comprising instructions executable by the processor151whereby the additional wireless device150is operative to perform the steps of the method800relating to network node150as described in conjunction withFIGS.8aand8b.

FIG.12cis a schematic view of a computer program product750according to one embodiment. The computer program product750comprises instructions which, when executed on at least one processor151or controller155of the network node150, cause the at least one processor150or controller155to carry out the method800and/or any other features listed in this disclosure related to the network node150.

FIG.13is a schematic view of a carrier700according to one exemplary embodiment. The carrier700may be any one of an electronic signal, an optical signal, a radio signal, or a computer readable storage medium. In one further embodiment of the carrier700, the carrier700comprises the computer program product710for the first wireless device110. In an alternative embodiment of the carrier700, the carrier700comprises the computer program product720for the second wireless device120. In another alternative embodiment of the carrier700, the carrier700comprises the computer program product730for the additional wireless device120. In another alternative embodiment of the carrier700, the carrier700comprises the computer program product750for the network node150.

The communication system3300further includes the UE3330already referred to. Its hardware3335may include a radio interface3337configured to set up and maintain a wireless connection3370with a base station serving a coverage area in which the UE3330is currently located. The hardware3335of the UE3330further includes processing circuitry3338, which may comprise one or more programmable processors, application-specific integrated circuits, field programmable gate arrays or combinations of these (not shown) adapted to execute instructions. The UE3330further comprises software3331, which is stored in or accessible by the UE3330and executable by the processing circuitry3338. The software3331includes a client application3332. The client application3332may be operable to provide a service to a human or non-human user via the UE3330, with the support of the host computer3310. In the host computer3310, an executing host application3312may communicate with the executing client application3332via the OTT connection3350terminating at the UE3330and the host computer3310. In providing the service to the user, the client application3332may receive request data from the host application3312and provide user data in response to the request data. The OTT connection3350may transfer both the request data and the user data. The client application3332may interact with the user to generate the user data that it provides.

It is noted that the host computer3310, base station3320and UE3330illustrated inFIG.15may be identical to the host computer3230, one of the base stations3212a,3212b,3212cand one of the UEs3291,3292ofFIG.14, respectively. This is to say, the inner workings of these entities may be as shown inFIG.15and independently, the surrounding network topology may be that ofFIG.14.

The wireless connection3370between the UE3330and the base station3320is in accordance with the teachings of the embodiments described throughout this disclosure. One or more of the various embodiments improve the performance of OTT services provided to the UE3330using the OTT connection3350, in which the wireless connection3370forms the last segment. More precisely, the teachings of these embodiments may, as previously explained, improve spectrum efficiency, reliability etc. and thereby provide benefits such as e.g. reduced user waiting time etc.

The following are a selection of numbered embodiments relating to the present disclosure.

1. A base station configured to communicate with a user equipment (UE), the base station comprising a radio interface and processing circuitry configured to perform the functions relating to the network node150of the method800.

5. A communication system including a host computer comprising:processing circuitry configured to provide user data; and a communication interface configured to forward the user data to a cellular network for transmission to a user equipment (UE), wherein the cellular network comprises a base station having a radio interface and processing circuitry, the base station's processing circuitry configured to perform the functions relating to the network node150of the method800.

6. The communication system of embodiment 5, further including the base station.

7. The communication system of embodiment 6, further including the UE, wherein the UE is configured to communicate with the base station.

8. The communication system of embodiment 7, wherein:the processing circuitry of the host computer is configured to execute a host application, thereby providing the user data; andthe UE comprises processing circuitry configured to execute a client application associated with the host application.

11. A method implemented in a base station, comprising the steps relating to the network node150of the method800.

16. The method of embodiment 15, further comprising:at the base station, transmitting the user data.

17. The method of embodiment 16, wherein the user data is provided at the host computer by executing a host application, the method further comprising:at the UE, executing a client application associated with the host application.

21. A user equipment (UE) configured to communicate with a base station, the UE comprising a radio interface and processing circuitry configured to perform the functions relating to the second wireless device120of the method800.

25. A communication system including a host computer comprising:processing circuitry configured to provide user data; anda communication interface configured to forward user data to a cellular network for transmission to a user equipment (UE),wherein the UE comprises a radio interface and processing circuitry, the UE's processing circuitry configured to perform the functions relating to the second wireless device120of the method800.

26. The communication system of embodiment 25, further including the UE.

27. The communication system of embodiment 26, wherein the cellular network further includes a base station configured to communicate with the UE.

28. The communication system of embodiment 26 or 27, wherein:the processing circuitry of the host computer is configured to execute a host application, thereby providing the user data; andthe UE's processing circuitry is configured to execute a client application associated with the host application.

31. A method implemented in a user equipment (UE), comprising performing the steps relating to the second wireless device120of the method800.

35. A method implemented in a communication system including a host computer, a base station and a user equipment (UE), the method comprising:at the host computer, providing user data; andat the host computer, initiating a transmission carrying the user data to the UE via a cellular network comprising the base station, wherein the UE is configured to perform the steps relating to the second wireless device120of the method800.

36. The method of embodiment 35, further comprising:at the UE, receiving the user data from the base station.

41. A user equipment (UE) configured to communicate with a base station, the UE comprising a radio interface and processing circuitry configured to perform the functions relating to the second wireless device120of the method800.

45. A communication system including a host computer comprising:a communication interface configured to receive user data originating from a transmission from a user equipment (UE) to a base station, wherein the UE comprises a radio interface and processing circuitry, the UE's processing circuitry configured to perform the functions relating to the second wireless device120of the method800.

46. The communication system of embodiment 45, further including the UE.

47. The communication system of embodiment 46, further including the base station, wherein the base station comprises a radio interface configured to communicate with the UE and a communication interface configured to forward to the host computer the user data carried by a transmission from the UE to the base station.

48. The communication system of embodiment 46 or 47, wherein:the processing circuitry of the host computer is configured to execute a host application; and the UE's processing circuitry is configured to execute a client application associated with the host application, thereby providing the user data.

49. The communication system of embodiment 46 or 47, wherein:the processing circuitry of the host computer is configured to execute a host application, thereby providing request data; andthe UE's processing circuitry is configured to execute a client application associated with the host application, thereby providing the user data in response to the request data.

51. A method implemented in a user equipment (UE), comprising the steps relating to the second wireless device120of the method800.

52. The method of embodiment 51, further comprising:providing user data; andforwarding the user data to a host computer via the transmission to the base station.

55. A method implemented in a communication system including a host computer, a base station and a user equipment (UE), the method comprising:at the host computer, receiving user data transmitted to the base station from the UE, wherein the UE is configured to perform the functions relating to the second wireless device120of the method800.

56. The method of embodiment 55, further comprising:at the UE, providing the user data to the base station.

57. The method of embodiment 56, further comprising:at the UE, executing a client application, thereby providing the user data to be transmitted; andat the host computer, executing a host application associated with the client application.

61. A base station configured to communicate with a user equipment (UE), the base station comprising a radio interface and processing circuitry configured to perform the functions relating to the network node150of the method800.

65. A communication system including a host computer comprising a communication interface configured to receive user data originating from a transmission from a user equipment (UE) to a base station, wherein the base station comprises a radio interface and processing circuitry, the base station's processing circuitry configured to perform the functions relating to the network node150of the method800.

66. The communication system of embodiment 65, further including the base station.

67. The communication system of embodiment 66, further including the UE, wherein the UE is configured to communicate with the base station.

68. The communication system of embodiment 67, wherein:the processing circuitry of the host computer is configured to execute a host application;the UE is configured to execute a client application associated with the host application, thereby providing the user data to be received by the host computer.

71. A method implemented in a base station, comprising the steps relating to the network node150of the method800.

75. A method implemented in a communication system including a host computer, a base station and a user equipment (UE), the method comprising:

at the host computer, receiving, from the base station, user data originating from a transmission which the base station has received from the UE, wherein the UE is configured to perform the steps relating to the second wireless device120of the method800.

76. The method of embodiment 75, further comprising:at the base station, receiving the user data from the UE.

77. The method of embodiment 76, further comprising:at the base station, initiating a transmission of the received user data to the host computer.