Methods and devices for enhanced acknowledgement reporting

Abstract

This disclosure relates to an access node (121) of a wireless network for managing downlink data transmission to a user equipment, UE (UE1), wherein the method comprises transmitting (404) a first data packet to the UE; and receiving, from the UE: an acknowledgement message (409), of successful decoding of the first data packet; and an indication (401, 410) of a decoding condition associated with the successful decoding. Receiving the indication may comprise receiving an indication of expiry of the decoding condition. This disclosure further relates to a User Equipment, UE, and methods for operating the access node and the UE.

Description

[0001] METHODS AND DEVICES FOR ENHANCED ACKNOWLEDGEMENT

[0002] REPORTING

[0003] Technical field

[0004] This disclosure is related to communication in wireless systems wherein wireless devices communicate with a radio network. Specifically, solutions are provided for enhancing feedback reporting from wireless devices, related to acknowledgement of received data managing.

[0005] Background

[0006] Various protocols and technical requirements for wireless communication have been standardized under supervision of inter alia the 3rd Generation Partnership Project (3GPP). Improvement and further development are continuously carried out, and new or amended functions and features are thus implemented in successive releases of the technical specifications providing the framework for wireless communication.

[0007] Wireless communication may in various scenarios be carried out between a network and a wireless device. The network typically comprises a core network and an access network, also referred to as RAN (Radio Access Network), including a plurality of access nodes, which historically have been referred to as base stations. In a 5G radio access network such a base station may be referred to as a gNB. Each access node may be configured to serve one or more cells of a cellular wireless network. A variety of different types of wireless devices may be configured to communicate with the access network, and such wireless devices are generally referred to as User Equipment (UE).

[0008] Where a UE receives data in downlink (DL), originating from the network, the UE is configured to provide feedback signaling to indicate level or proper reception and decoding of the data, and whether the decoding is successful or not successful. Upon receiving the data, the UE checks for errors. If the received data is error-free, it may send an acknowledgment (ACK) to the network. If errors are detected, a negative acknowledgment (NACK) is sent. This may be referred to as acknowledgement reporting. A NACK may typically configure the network to execute retransmission, either a complete data packet or only additional information rather than the entire packet. For such retransmission, or other further transmission, the access node carrying out the DL transmission may further adapt the radio link based on the acknowledgment reporting, so as to securely convey data to the UE without required retransmission while conserving radio resources.

[0009] However, in certain scenarios, the network may lack full knowledge of reception and decoding capability of the UE, such as when the UE is assisted by or dependent on a particular resource for reception or decoding. In such scenarios, legacy acknowledgement reporting may lead to waste of radio resources caused by undue transmission or link adaptation.

[0010] Summary

[0011] An overall objective of the proposed solution is to provide improvement in the field of acknowledgement reporting in the context of DL transmission from a radio network of data intended for a UE. The proposed solution is defined by the terms of the independent claims, whereas further aspects and details are set out in the dependent claims and in the description below.

[0012] According to one aspect, a method carried out in an access node of a wireless network is provided for managing downlink data transmission to UE, wherein the method comprises: transmitting a first data packet to the UE; receiving, from the UE: an acknowledgement message of successful decoding of the first data packet; and an indication of a decoding condition associated with the successful decoding.

[0013] According to another aspect, a method carried out in UE is provided, configured to receive downlink data transmitted from an access node of a wireless network, wherein the method comprises: receiving a first data packet originating from the access node; obtaining successful decoding of the first data packet under a decoding condition; transmitting, to the access node: an acknowledgement message of decoding of the first data packet; and an indication of the decoding condition.

[0014] Based on the proposed solution, by means of which the UE informs the network of the decoding condition at which the first data packet was obtained, the access node obtains enhanced information for configuring further downlink data transmission to the UE, wherein the access node may configure such further data transmission based on both the acknowledgement and the indication of the decoding condition. This may entail properly allocating resources or configuring robustness for further data transmissions. This improves capability of the access node to allocate resources and to adapt the radio link, compared to traditional binary acknowledgement.

[0015] Brief description the drawings

[0016] Fig. 1 schematically illustrates a wireless communication system, in which a wireless network is configured to communicate with UEs.

[0017] Fig. 2 schematically illustrates a UE configured to operate in the wireless system according to various examples of the proposed solution.

[0018] Fig. 3 schematically illustrates an access node of the wireless network according to various examples of the proposed solution.

[0019] Fig. 4 shows a first signaling diagram, illustrating various aspects and examples of the proposed solution.

[0020] Fig. 5 shows a second signaling diagram, illustrating various aspects and examples of the proposed solution.

[0021] Detailed description

[0022] In the following description, for the purposes of explanation and not limitation, details are set forth herein related to various examples. However, it will be apparent to those skilled in the art that the present invention may be practiced in other examples that depart from these specific details. In some instances, detailed descriptions of well- known devices, circuits, and methods are omitted so as not to obscure the description of the present invention with unnecessary detail. The functions of the various elements including functional blocks, including but not limited to those labeled or described as “computer”, “processor” or “controller”, may be provided through the use of hardware such as circuit hardware and / or hardware capable of executing software in the form of coded instructions stored on computer readable medium. Thus, such functions and illustrated functional blocks are to be understood as being either hardware-implemented and / or computer-implemented and are thus machine-implemented. In terms of hardware implementation, the functional blocks may include or encompass, without limitation, digital signal processor (DSP) hardware, reduced instruction set processor, hardware (e.g., digital or analog) circuitry including but not limited to application specific integrated circuit(s) (ASIC), and (where appropriate) state machines capable of performing such functions. In terms of computer implementation, a computer is generally understood to comprise one or more processors or one or more controllers, and the terms computer and processor and controller may be employed interchangeably herein. When provided by a computer or processor or controller, the functions may be provided by a single dedicated computer or processor or controller, by a single shared computer or processor or controller, or by a plurality of individual computers or processors or controllers, some of which may be shared or distributed. Moreover, use of the term “processor” or “controller” shall also be construed to refer to other hardware capable of performing such functions and / or executing software, such as the example hardware recited above.

[0023] Before presenting aspects and examples of the proposed solution, context and devices for use of the proposed solution will be briefly described with reference to the drawings. The drawings are to be regarded as being schematic representations and elements illustrated in the drawings are not necessarily shown to scale. Rather, the various elements are represented such that their function and general purpose become apparent to a person skilled in the art. Any connection or coupling between functional blocks, devices, components, or other physical or functional units shown in the drawings or described herein may also be implemented by an indirect connection or coupling. A coupling between components may also be established over a wireless connection. Functional blocks may be implemented in hardware, firmware, software, or a combination thereof.

[0024] Fig. 1 illustrates a wireless system, in which UEs may communicate wirelessly by radio signaling with a wireless network 100. Fig. 1 is useful for context of the proposed solution and illustrates various entities and functions which cooperate in wireless system. The wireless network 100 may be a radio communication network 100, configured to operate under the provisions of 5G as specified by 3GPP, according to various examples, or further generations.

[0025] The wireless network 100 may comprise a core network (CN) 110, connectable to an external network 130 such as the Internet. The core network may comprise a plurality of core network nodes, which realize logical functions. Data destined for UEs of the system may originate from the CN 110, or from application functions or serves deployed outside of the 5G system, connected to the CN 100 through the external network 130.

[0026] The wireless network 100 further comprises an access network 120, comprising a plurality of access nodes (AN), configured for radio communication on a radio channel. By way of example, the drawing indicates a first radio channel 141 connecting the access node 121 and a UE1, and a second radio channel 142 connecting the access node 121 and a UE2. Moreover, the access node 121 may configure a radio channel 143 for de vice-to -device (D2D) communication between UE1 and UE2. This may in various examples be referred to as Sidelink communication, which as such is a legacy 3GPP procedure.

[0027] Before proceeding with details of the proposed solution, a brief description of various elements will be provided, which may be configured to carry out the proposed solution.

[0028] Fig. 2 schematically illustrates an example of a UE 10 configured to communicate with the wireless network 100 as presented herein and configured for carrying out various method steps as outlined. The drawing shows some relevant elements or functions of the UE 10 are shown in the drawing. The UE 10 may however include other features and elements than those shown in the drawing or described herein, such as a power supply, a casing, a user interface, sensors, etc., but these are left out for the sake of simplicity. Any one of UE1 and UE2 may be realized in accordance with UE 10.

[0029] The UE 10 comprises a radio transceiver 213, also referred to herein as modem 213, for communicating in one or more frequency bands with other entities of the radio communication network 100, such as with the access node 121 or with another UE over an air interface, such as by Sidelink communication. The transceiver 213 may thus include a receiver chain (Rx) and a transmitter chain (Tx), for communicating through at least an air interface, referred to as Un in 3GPP. The transceiver 213 may be or comprise a modem configured to encode, transmit, receive and decode data, conveyed using radio waves.

[0030] The UE 10 may further comprise an antenna system 214, which may include one or more antennas, antenna ports or antenna arrays. The antenna system 214 is connected to the transceiver 213.

[0031] The UE 10 further comprises logic circuitry 210 configured to control data and signal communication via the radio transceiver on a physical channel, such as channel 141, 142, 143 to a serving access node of the wireless network 100, and data decoding. The logic circuitry is further configured to control the UE to carry out any of the steps associated with the proposed solution as outlined herein.

[0032] The logic circuitry 210 may include a processing device 211, including one or multiple processors, microprocessors, data processors, co-processors, and / or some other type of component that interprets and / or executes instructions and / or data. The processing device 211 may be implemented as hardware (e.g., a microprocessor, etc.) or a combination of hardware and software (e.g., a system-on-chip (SoC), an applicationspecific integrated circuit (ASIC), etc.). The processing device 211 may be configured to perform one or multiple operations based on an operating system and / or various applications or programs.

[0033] The logic circuitry 210 may further include memory storage 212, which may include one or multiple memories and / or one or multiple other types of storage mediums. For example, the memory storage 212 may include a random access memory (RAM), a dynamic random access memory (DRAM), a cache, a read only memory (ROM), a programmable read only memory (PROM), flash memory, and / or some other type of memory. The memory storage 212 may include a hard disk (e.g., a magnetic disk, an optical disk, a magneto-optic disk, a solid state disk, etc.). The memory storage 212 is configured for holding computer program code, which may be executed by the processing device 211, wherein the logic circuitry 210 is configured to control the UE 10 to carry out any of the method steps as provided herein. Software defined by said computer program code may include an application or a program that provides a function and / or a process. The software may include device firmware, an operating system (OS), or a variety of applications that may execute in the logic circuitry 210. Fig. 3 schematically illustrates a radio node in the form of an access node 121 of the wireless network 100 as presented herein, and for carrying out various method steps as outlined. In various examples, the access node 121 is a radio base station for operation in the radio communication network 100, to serve one or more radio UEs, such as UE1 and UE2, configured as UE 10.

[0034] The access node 121 may comprise a wireless transceiver 313, such as a radio transceiver for communicating with other entities of the radio communication network 100, such as the UE1. The transceiver 313 may thus include a radio receiver and transmitter for communicating through at least an air interface. The transceiver may comprise a radio modem.

[0035] The access node 121 may further comprise, or be connected to, an antenna 314 which may comprise a plurality of antennas (antenna elements) in an array configuration. The antenna array 314 is connected to the transceiver 313.

[0036] The access node 121 further comprises logic circuitry 310 configured to control the access node 121 to communicate with the UEs via the radio transceiver 313 on a physical channel. The logic circuitry 310 may be configured for resource allocation and may realize a scheduler for scheduling communication of a data. The logic circuitry 310 may further be configured to make link adaptation on radio channels to UEs, e.g., by adjusting modulation and decoding to reconfigure robustness of DL data transmission.

[0037] The logic circuitry 310 may include a processing device 311, including one or multiple processors, microprocessors, data processors, co-processors, and / or some other type of component that interprets and / or executes instructions and / or data. Processing device 311 may be implemented as hardware (e.g., a microprocessor, etc.) or a combination of hardware and software (e.g., a system-on-chip (SoC), an applicationspecific integrated circuit (ASIC), etc.). The processing device 311 may be configured to perform one or multiple operations based on an operating system and / or various applications or programs.

[0038] The logic circuitry 310 may further include memory storage 312, which may include one or multiple memories and / or one or multiple other types of storage mediums. For example, memory storage 312 may include a random access memory (RAM), a dynamic random access memory (DRAM), a cache, a read only memory (ROM), a programmable read only memory (PROM), flash memory, and / or some other type of memory. Memory storage 312 may include a hard disk (e.g., a magnetic disk, an optical disk, a magneto-optic disk, a solid state disk, etc.). The memory storage 312 is configured for holding computer program code, which may be executed by the processing device 311, wherein the logic 310 is configured to control the access node 121 to carry out any of the method steps as provided herein. Software defined by said computer program code may include an application or a program that provides a function and / or a process. The software may include device firmware, an operating system (OS), or a variety of applications that may execute in the logic 310.

[0039] The access node 121 may further comprise an interface 315, configured for communication with the core network 110.

[0040] The proposed solution relates to scenarios where ability of the UE to properly obtain DL data, i.e., data reception and decoding, may vary dependent on circumstances unknown to the network 100. In this context, successful decoding may depend on a resource that is associated with a constraint which is known to the UE.

[0041] According to one aspect, the proposed solution comprises an access node 121 of a wireless network 100, configured for managing downlink data transmission to a UE1. The access node 121 comprises a radio transceiver 313, and logic circuitry 310 configured to control the access node to transmit a first data packet to the UE1, and to receive, from the UE: an acknowledgement message of successful decoding of the first data packet; and an indication of a decoding condition associated with the successful decoding. According to another aspect, the proposed solution comprises a UE1, configured to receive downlink data transmitted from an access node 121 of a wireless network 100. The UE 1 comprises a radio transceiver 213, and logic circuitry 210 configured to control the UE 1 to receive a first data packet originating from the access node, and obtaining successful decoding of the first data packet under a decoding condition, wherein the UE1 is configured to transmit, to the access node 121: an acknowledgement message of decoding of the first data packet; and an indication of the decoding condition.

[0042] By means of the proposed solution, the access node is enabled to configure further data transmission based on both the acknowledgement and the indication of the decoding condition. This may entail properly allocating resources or configuring robustness for further data transmissions. The decoding condition may indicate that reception and / or decoding of the data was dependent on a resource associated with a constraint. In some examples, the indication of the decoding condition is indicative of a change of ability to receive and / or decode data, such as a known or predicted degradation of ability of the UE1 to receive and / or decode data. The indication may thus be transmitted upon the UE1 determining that the decoding condition under which obtainment of the first data packet was successful, is set to expire or has expired. In this context, the decoding condition under which the first data packet was obtained may represent expected capacity of the UE1 to receive and / or decode data, wherein the indication is transmitted when the capacity is degraded or worsened. In some examples, the UE1 may be configured to operate in collaboration with an auxiliary resource, such as an assisting UE2, and the access node may have been notified in advance of this as a temporary decoding condition. The decoding condition for data obtainment may thus be reception and / or decoding with assistance from that other resource, wherein the indication of the decoding condition may comprise an indication of availability time or expiry of the availability of the auxiliary resource.

[0043] The transmission of the acknowledgement message indicating successful decoding, in combination with the indication of the decoding condition, alerts the access node that transmission of further data to the UE1 may require tuning in order to be successful. This may, as such, be obtained by enhanced resource allocation and / or adaptation of the link to increase robustness by configuring a different level modulation and coding scheme.

[0044] Various features and examples of the proposed solution will be described below with reference to Figs 4 and 5, mainly in the form of method steps. However, it should be understood that the proposed solution may be realized by means of apparatuses UE1 and 121, configured to carry out these steps.

[0045] Fig. 4 illustrates a signaling diagram in the context of DL data transmission from the access node 121 to the UE1. According to some examples, described below with reference to Fig. 4, decoding dependent on a resource that is associated with a constraint may take place case when the UE1 is assisted by or dependent on a particular auxiliary resource for reception or decoding. In such scenarios, legacy acknowledgement reporting may not be appropriate for assisting the access node to properly adapt the radio link. Before specifically referring to examples supported in Fig. 4, it may be noted those examples of the proposed solution as set out in the context of the UE obtaining data by making use of an auxiliary decoding resource, such as an assisting UE2. This way, the UE1 may obtain decoding of the first data packet by collaboration or aggregation together with the auxiliary resource. The auxiliary resource may be another device in close proximity to the UE1. According to some examples, the collaboration may be obtained by Sidelink communication with the auxiliary resource, whereas other examples may include other connectivity types between the UE1 and the auxiliary resource, such as Bluetooth, Wi-Fi, or wired connection. Details of the means of connectivity with the auxiliary resource for collaboration are not laid out herein, and although some examples are provided, the specific type of connectivity is not relevant for the proposed solution. It shall be noted that in some examples, the auxiliary device need not be a device which operates with the network 100 but is otherwise connectable to the UE1. In other examples, the auxiliary device is another UE connectable to the network 100, to, inter alia, receive DL data. As shown in the drawing, and used herein, the auxiliary device is labelled UE2 for any of those examples, and shall not be read as the auxiliary device being restricted to a UE connected or known to the network 100.

[0046] Various scenarios for such a collaboration are foreseeable:

[0047] The data which is scheduled and intended for the UE1 is received in the auxiliary resource from the network 100, decoded, and conveyed to the UE1. The UE1 receives the data from the network 100, and decodes it in collaboration with the auxiliary resource, e.g., by combining computing resources.

[0048] The UE1 partially obtains the data from the network 100 and obtains additional information (rather than the full data packet) from the auxiliary resource, to enable complete error-free decoding.

[0049] In any of these examples, and after abstracting away the precise collaboration type, the DL transmission of the first data packet may have one of three outcomes:

[0050] 1. UE1 manages to decode the first data packet without any help from the auxiliary resource UE2.

[0051] 2. UE1 fails to decode the first data packet on its own but manages with collaboration help from UE2.

[0052] 3. UE1 fails to decode its data packet despite collaboration with UE2. In each case, the UE1, which is the intended recipient of the first data packet, shall provide acknowledgement reporting to the network 100. This entails sending an acknowledgement message. According to legacy procedures, the acknowledgement message may comprise an ACK or a NACK. For case 1, the acknowledgement message would typically be an ACK, whereas for case 3 it would be a NACK. However, the situation is unclear for case 2. This is related, inter alia, to the concept of Open Loop Link Adaptation (OLLA). OLLA is a cornerstone of any communication system. Despite its name, OLLA is always applied by the network 100 even in closed loop systems. This allows the network to override the UE feedback. A closed loop means that the UE (e.g., UE1) reports information to the network 100 on what transmission scheme to be used in the DL. This information may either be raw channel estimates (expensive), or a suggested modulation scheme to be used (cheaper, and more common). Due to the complex nature of resource scheduling for contemporary wireless systems, the network may, for a variety of reasons, override said suggestion. OLLA can be done in many ways, but a standard algorithm is to use the following.

[0053] Input: A list of modulation and coding schemes (MCS), represented as indices 1...T, where scheme 1 has lowest data rate, for example BPSK (Binary Phase- Shift Keying) with code rate 1 / 4, and scheme T has highest, for example 64QAM (Quadrature Amplitude Modulation) with code rate 5 / 6. Initialize the MCS as x = a. Initialize an auxiliary variable y = a.

[0054] For every ACK / NACK received from the UE, the network: a) Updates y as

[0055] ( 1 y + — , For a received Ack y = j 10 ly — 1, For a received Nack b) Determines a candidate MCS as x = y ] c) Selects the applied MCS by choosing either x or the suggestion by the UE.

[0056] Although this is an example of OLLA in its simplest form, it does capture the essential behavior of OLLA procedures. The typical behavior is that it requires many consecutive ACKs before the network increases the MCS (in this example, it would require 10 ACKs due to the term 1 / 10). However, a single NACK is required for the MCS to be decreased. It may be noted that if the UE reports a suggested MCS, say MCS=7, but the OLLA currently stands at, say, y=12.4, so that it would in absence of the UE’s suggestion apply MCS x = [12.4] = 12, then typically the network overrides the UE suggestion and applies the higher MCS. This is done to quickly transfer data to the UE to free up resources for others. The network feels safe in doing so, since the value y = 12.4 can only be reached through a long string of Acks, which means that the data transfer works well.

[0057] Based on the above, it may be noted that if UE1 cannot decode data packets on its own but is able to decode them via assistance from UE2 (i.e., Case 2), reporting ACKs to the network would result in a negative spiral. The MCS would increase due to the OLLA, and then it is even more difficult for the UE to decode data. If UE2 offers UE1 unrestricted assistance, then this may be fine. However, if UE2 can only temporarily or sporadically assist, for example due to power drainage or limited connection between UE1 and UE2, then UE1 must be able to independently decode its data most of the times. On the other hand, reporting NACK from the UE1 is also inappropriate, since that would lead to HARQ (Hybrid Automatic Repeat reQuest) retransmission which would be totally redundant - after all, UE1 did obtain decoding of the data packet.

[0058] It may thus be suggested to introduce a third parameter or signal to complement the binary pair ACK / NACK. Multilevel ACK / NACK systems have been proposed before in the documents "Reliability-based hybrid ARQ", John M. Shea, Electronics letters vol. 38, no. 13, 2002, pp. 644-645; "Multilevel type-II HARQ with adaptive modulation control", Roberto Bosisio et al., IEEE Wireless Communications and Networking Conference, 2006. WCNC 2006; ’’Multilevel Control Signaling for Hybrid ARQ”, Y. Wang et al., Proc. International Conf, on Wireless Communications, Networking and Mobile Computing, WiCOM’08, 2008; "Performance of asymmetric QPSK modulation for multi-level ACK / NACK in LTE uplink", Volker Braun et al., European Wireless 2014; 20th European Wireless Conference. VDE, 2014; and in US2016261321A1. Common to all these documents is that they outline procedures where feedback report is calculated based on the received version of the transmitted signal, i.e., based on the history.

[0059] Returning to Fig. 4, it shall be noted that not all steps shown in the drawing need to be included in every example of the proposed solution. Various different examples are provided below. 401 denotes indication, from the UE1 to the access node 121, of a decoding condition, identifying assistance of auxiliary device UE2. This may include UE1 signaling that it is part of a UE assistance scheme.

[0060] 402 indicates a specific and optional example, where the indication 401 identifies a UE2 which is connectable to the network 100, and where the access node 121 configures the UE1 and / or the UE2 for Sidelink communication, which as such may be carried out according to legacy procedures.

[0061] 403 indicates that the access node provides control data indicating MCS to the UE1. In various examples, resource allocation and scheduling for receiving DL data may be configured by the access node and provided to the UE1 in step 402 or 403, or alternatively in a separate step.

[0062] 404 indicates that payload data, comprising the first data packet, is sent in DL from the access node 121 for reception in the UE1.

[0063] 405-408 indicate successful decoding of the first data packet under a decoding condition, which in this context comprises collaboration between the UE1 and the UE2. This corresponds to Case 2 described above. While these steps indicate specific steps, the collaboration may comprise any of the examples outlined above.

[0064] 405 indicates that UE1 detects errors in decoding, hence decoding failure.

[0065] 406 indicates that the UE1 requests assistance from the UE2.

[0066] 407 indicates that the UE1 obtains assistance from the UE2.

[0067] 408 denotes obtainment in UE1 of error-free decoding of the pay load data, carried out with the assistance of UE2.

[0068] 409 indicates that the UE1 transmits an acknowledgement message of decoding of the payload data. In this context, the acknowledgement message is interpreted by the network as a soft ACK, indicating “The UE1 failed to decode, but could decode with assistance”. For link adaptation purposes, the acknowledgement message is accounted for as a NACK, but for HARQ purposes it is accounted for as an ACK.

[0069] The UE1 may thus requests assistance from the assisting UE, UE2, whenever experiencing a decoding failure. If granted (by the UE2), and the assistance is sufficient for a decoding success, the UE may signal a soft Ack to the access node 121.

[0070] 410 indicates that, in some examples, the acknowledgement message may, completely or partly, comprise the indication of the decoding condition, such as expiry of the decoding condition. 411 indicates that the access node 121 controls the MCS according to applied OLLA principles, and possibly also other parameters such as, e.g., DMRS density (Demodulation Reference Signal), and transmits control data indicative thereof to the UEL However, no HARQ retransmission is triggered by the acknowledgment message.

[0071] 412 indicates that further, subsequent, payload data is transmitted by the access node 121 for reception in the UE1, according to the (updated) MCS provided in step 411.

[0072] The access node 121 is thus enabled, based on the indication of the decoding condition, to configure transmission properties, such as the MCS, for a further data packet (412) under the pretext of the first data packet received in the UE1 at step 404 not being acknowledged - NACK. This way, the UE1 may be enabled to obtain decoding success on the next payload data of step 412, without assistance from UE2.

[0073] Various aspects and examples related to the solution outlined with reference to Fig. 4 will now be described.

[0074] In some examples, receiving the indication of a decoding condition comprises receiving an indication of expiry of the decoding condition. This may indicate that the decoding condition has expired, or that it is set to expire at some time after the successful decoding. This indication of expiry may be transmitted in, or in association with, the acknowledgement message of step 409.

[0075] In some examples, step 401 may comprise receiving a message in the access node 121, indicating presence of the decoding condition. In one example, said message is indicative of availability time of the auxiliary decoding resource UE2, given that this is known or predicted by the UE1, e.g., communicated to UE2 from UEL Alternatively, the message indicative of availability time of the auxiliary decoding resource UE2 may be transmitted directly from UE2 to the access nodel21. The indication of availability time of the auxiliary decoding resource, in combination with timing of the transmission of the payload data 404, may configure the access node to properly interpret the acknowledgement message 409. If the availability time indicates that UE2 was likely not available to assist the UE1 with the decoding, i.e., that access to the UE2 for decoding assistance had expired, an ACK or NACK received in the acknowledgement message of step 409 may be interpreted as it is indicated. However, if the availability time indicates that UE2 was likely available to assist the UE1 with the decoding but that availability is set to expire before the next transmission 412, an ACK or NACK received in the acknowledgement message of step 409 may be interpreted as a NACK for link adaptation purposes, based on which the control data of 411 may indicate updated MCS. The indication of availability time received in step 401 may thus indicate expiry of the decoding condition.

[0076] In some examples, the indication of step 401 may trigger the access node 121 to configure the UE, e.g., in step 403 or by separate messaging, to enable acknowledgement message transmission, wherein the acknowledgement message 409 is indicative of expiry of the decoding condition. In this context, the access node 121 may activate the possibility of a third acknowledgement option, which can be referred as a soft ACK. In one example, this entails activating use of an additional resources for indicating feedback. In some examples, the activation of soft ACK reporting and configuring of the UE1 is made upon determining a temporary decoding condition for the UE1, based on knowledge of existing Sidelink configuration as configured in step 402. The acknowledgement of decoding may be configured to comprise at least two bits, to indicate ACK, NACK, or soft ACK. Alternatively, an indication of the acknowledgement message representing a soft ACK is transmitted separately of the actual ACK or NACK message.

[0077] Nevertheless, by means of the indication of step 401, activation of this possibility of soft ACK reporting can be selectively carried out by the access node 121. This means that additional resources for this purpose need not always be configured, as it generally (when UE1 acts alone) would serve no purpose.

[0078] In some examples, the indication of the decoding condition, such as expiry of the decoding condition, may be communicated by UE-proposed transmission properties, such as proposed MCS or MCS adjustment. The proposed transmission properties may be comprised in the acknowledgement message 409 or sent separately. The access node 121 may thus be configured, based on the combination of the acknowledgement message and the proposed transmission properties, to identify the acknowledgement message as a soft ACK. In the scenario of the first payload data being decoded with assistance 408, and the availability of the assistance having expired or being deemed to expire, soft ACK reporting may e.g., be achieved by the UE1 transmitting an ACK in the acknowledgement message 409 and transmitting proposed transmission properties indicating a request for increased robustness of subsequent payload data transmission 412. While the signaling diagram of Fig. 4 indicates use of an external auxiliary resource, it shall be noted that the auxiliary resource may optionally be comprises within the UE1. In this context, the UE1 may be capable of decoding 408 the received payload data 404 by switching to a higher complexity mode. In certain scenarios, of for certain types of UEs, such as low-power devices, use of the higher complexity mode would ideally be avoided. Hence, the UE1 may indicate 410, in the acknowledgement message 409 or separately, that more robust transmission properties are requested. This way, the indication 410 may indicate expiry, or requested expiry, of the decoding condition used to successfully decode 408 the payload data 404. Such indication may, e.g., be transmitted due to current battery level falling below a certain level.

[0079] Fig. 5 illustrates another example, or group of examples, of the proposed solution. The same reference numerals as in Fig. 4 are used to denote corresponding actions.

[0080] In these examples, the indication of the decoding condition may be indicative of entering a constrained functional state of the UE1. This may e.g., be determined based on detected low battery level in the UE1, a temperature level recorded in the UE1 outside a certain temperature range, or damage or malfunction detected in one or more components in the UE1. The constrained functional state may comprise reduced data reception capacity, e.g., due to deactivation of one or more antennas of the antenna 214, and / or reduced decoding capacity in the UE1.

[0081] In some examples, the indication of the decoding condition indicative of entering a constrained functional state of the UE1 may comprise reporting 401 an indication of expected or known future timing of entering the constrained functional state. Alternatively, it may comprise reporting 410 entry of the constrained functional state in, or in association with, the acknowledgement message.

[0082] In some examples, the indication of the decoding condition may comprise a parameter value, representing functional or operational level of the UE1, wherein a certain parameter value, or any value above or below a certain threshold level, indicates a constrained functional state of the UE1. In various examples, the parameter is binary, indicating normal operation or constrained functional state (reduced operation ability). In other examples, the parameter may assume one of more than two different values, indicating different levels of constrained functional state, or different types of constrained functional state. In some examples, the indication of the decoding condition may identify a cause or type of the constrained functional state, such as any of those mentioned above.

[0083] The access node 121 is thus configured to determine and report 411 control data for further payload transmission 412 based on the acknowledgement message 409 in combination with the indication of entering a constrained functional level of the UE1, wherein the access node 121 is configured to interpret the acknowledgement message 409 as a soft ACK. Based on the indication of the decoding condition being indicative of entering a constrained functional state of the UE1, subsequent to the successful decoding 408 of the first payload data 404 the access node 121 is enabled to reconfigure connection 411 to the UE1 for further data transmission 412, even if the acknowledgement message indicates successful decoding (ACK) of the first data packet.

[0084] The proposed solution as described herein provides for improved acknowledgement (feedback) messaging responsive to reception and decoding of payload data under certain decoding resource. In particular, various aspects of the proposed solution provide improved basis for enabling the access node 121 to determine reconfiguration of transmission properties responsive to successful decoding, where the decoding condition is indicated to change or expire. In other words, allowing the access node 121 to take future change of the decoding condition into account. The proposed solution thus incorporates information on known changes in decoding conditions that will occur. For the example of collaboration with the UE2, in situations where the UE2 cannot offer any further assistance, it is known to the UE1 that NACKs will result in case the MCS is not decreased. In some examples, the proposed solution thus enables the access node 121 to configure transmission properties for a further payload data 412 under the pretext of the first payload data 404 not being acknowledged. By reference to the earlier example and discussion related to OLLA, this may allow the access node 121 to control MCS bas on the following: Various aspects of the proposed solution have been outlined in the foregoing. The proposed solution may be embodied in accordance with any of those aspects within the scope defined by the appended claims.

Claims

CLAIMS1. A method carried out in an access node of a wireless network for managing downlink data transmission to a user equipment, UE, wherein the method comprises: transmitting (404) a first data packet to the UE; receiving, from the UE: an acknowledgement message (409) of successful decoding of the first data packet; and an indication (401, 410) of a decoding condition associated with the successful decoding.

2. The method of claim 1, wherein receiving the indication comprises: receiving (401, 410) an indication of expiry of the decoding condition.

3. The method of claim 1 or 2, wherein the acknowledgement message is configured to identify expiry (410) of the decoding condition after the successful decoding.

4. The method of any preceding claim, wherein said indication comprises UE- proposed transmission properties (410) associated with the decoding condition.

5. The method of any preceding claim, comprising: configuring (403) the UE to enable acknowledgement message transmission, wherein the acknowledgement message is indicative of expiry of the decoding condition.

6. The method of claim 5, wherein the configuring is made upon determining (401, 402) a temporary decoding condition for the UE.

7. The method of any preceding claim, wherein receiving the indication comprises: receiving (401) a message indicating presence of the decoding condition.

8. The method of any preceding claim, wherein said decoding condition comprises use of an auxiliary decoding resource.

9. The method of claim 7 and 8, wherein said message is indicative (401) of availability time of the auxiliary decoding resource.

10. The method of claim 8 or 9, wherein the auxiliary decoding resource is an assisting UE connectable to the UE.

11. The method of any of claims 1-4, wherein the indication is indicative (410) of entering a constrained functional state of the UE.

12. The method of any preceding claim, wherein the access node is enabled, based on the indication, to configure (411) transmission properties for a further data packet (412) under the pretext of the first data packet not being acknowledged.

13. An access node (121) of a wireless network (100), configured for managing downlink data transmission to a user equipment (UE1), said access node comprising: a radio transceiver (313), and logic circuitry (310), wherein the logic circuitry is configured to control the access node to carry out the steps of any of claims 1-12.

14. A method carried out in a user equipment, UE, configured to receive downlink data transmitted from an access node of a wireless network, wherein the method comprises: receiving (404) a first data packet originating from the access node; obtaining (408) successful decoding of the first data packet under a decoding condition; transmitting, to the access node: an acknowledgement message (409) of decoding of the first data packet; and an indication (401, 410) of the decoding condition.

15. The method of claim 14, wherein transmitting the indication comprises:transmitting an indication of expiry of the decoding condition.

16. The method of claim 14 or 15, wherein the acknowledgement message is configured to identify expiry of the decoding condition after the successful decoding.

17. The method of any of claims 14-16, wherein said indication comprises UE- proposed transmission properties associated with the decoding condition.

18. The method of any of claims 14-17, comprising: receiving, from the access node, configuration to enable acknowledgement message transmission indicative of expiry of the decoding condition.

19. The method of any of claims 14-18, wherein transmitting the indication comprises: transmitting a message indicating presence of the decoding condition.

20. The method of any preceding claim, wherein said decoding condition comprises use of an auxiliary decoding resource.

21. The method of claim 19 and 20, wherein said message is indicative of availability time of the auxiliary decoding resource.

22. The method of claim 20 or 21, wherein the auxiliary decoding resource is an assisting UE connectable to the UE.

23. The method of any of claims 14-17, wherein the indication is indicative of entering a constrained functional state of the UE.

24. The method of any of claims 14-23, wherein the indication enables the access node to configure transmission properties for a further data packet under the pretext of the first data packet not being acknowledged (NACK).

25. A user equipment, UE (UE1), configured to receive downlink data transmitted from an access node (121) of a wireless network (100), said UE comprising: a radio transceiver (213), and logic circuitry (210), wherein the logic circuitry is configured to control the UE to carry out the steps of any of claims 14-24.

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