Network node and method for prioritization of feedback message in wireless communication system

Abstract

A first node (330 / 311) and method therein for handling transmission of one or multiple feedback messages related to one or multiple data receptions in a wireless communication system (300) are provided. The first node (330 / 311) determines to send one or multiple feedback messages indicating status of one or multiple data receptions to a second node (311 / 330), determines a priority or an order for the one or multiple feedback messages; and sends the one or multiple feedback messages based on the priority or order of the feedback messages on a data transmission channel to the second node (311 / 330).

Description

NETWORK NODE AND METHOD FOR PRIORITIZATION OF FEEDBACK MESSAGE IN WIRELESS COMMUNICATION SYSTEMTECHNICAL FIELD

[0001] Embodiments herein relate to network nodes, communication devices and methods therein for handling feedback messages in a wireless communication system. In particular, embodiments herein relate to transmission of feedback messages related to one or multiple data receptions.BACKGROUND

[0002] In a typical wireless communication network or system, wireless devices, also known as wireless communication devices, mobile stations, and / or user equipment (UE), communicate via a Radio Access Network (RAN) to one or more core networks (CN). A radio network node, which may also be referred as a network node, a RAN node, gNB, eNB, an access node, communicates over an air interface operating on radio frequencies with one or more wireless communication device within a range of the radio network node.

[0003] A Universal Mobile Telecommunications System (UMTS) is a third generation (3G) telecommunication network, which evolved from the second generation (2G) Global System for Mobile Communications (GSM). Specifications for the Evolved Packet System (EPS), also called a Fourth Generation (4G) network or Long Term Evolution (LTE) have been completed within the 3rd Generation Partnership Project (3GPP) and this work continues in the coming 3GPP releases, for example to specify a Fifth Generation (5G) New Radio (NR) network, Next Generation (NG) and upcoming releases.

[0004] The 5G user-plane architecture and protocols are described with reference to Figure 1. UE is connected over the air interface via Uu protocol with a RAN node, gNB. The gNB may be separated into a distributed unit (DU), gNB-DU, and a centralized unit (CU), gNB-CU, connected via Fl interface. The gNB is connected to core network, CN, including user-plane function, UPF. Typically, Internet Protocol (IP) data is transported via UE-gNB- UPF. The RAN protocol stack between UE and gNB includes Service Data Adaptation Protocol, SDAP, for handling mapping of Quality of Service (QoS) flows as established by the UPF to data radio bearers (DRBs) as established by the gNB. The Protocol Data Convergence Protocol, PDCP, is among others responsible for encryption or integrity protection and handover forwarding and retransmission. For handovers between gNBs, Xn interface is employed. The radio link control, RLC, is among others responsible forsegmentation of higher layer PDCP / IP data to fit the transport blocks (TBs) available for the lower layer over the air transmission. Also, retransmissions are based on automatic repeat request (ARQ) in acknowledged mode of RLC. Medium Access Control, MAC, protocol supports scheduling of transmissions over the air interface and entails hybrid automated repeat request (HARQ) protocol. The physical layer, PHY, handles e.g. modulation and coding and the actual physical transmission.

[0005] In 3GPP radio access networks, e.g. 5GNR, the HARQ protocol facilitates retransmissions of data in case of transmission errors over the air interface.

[0006] For downlink HARQ, data transmissions are assigned by downlink control indicators (DCI) carried on the physical downlink control channel (PDCCH) and data is transmitted on the physical downlink shared channel (PDSCH). Different encoding is applied to these channels resulting in different error rates. HARQ feedback, i.e. positive (ACK) or negative acknowledgement (NACK) of data reception from the UE is transmitted as uplink control information (UCI) either on the physical uplink control channel (PUCCH) or physical uplink shared channel (PUSCH) multiplexed with other uplink data since simultaneous transmission of PUCCH and PUSCH imposes challenges on the radio frequency (RF) implementation. Different encoding of these channels may result in different error rates, where transmission on PUCCH is typically more robust. However, it is noteworthy that the transmissions on the PUSCH undergo the uplink HARQ protocol, i.e. are also subject to retransmissions to correct any decoding errors. Furthermore, the code rate for UCI on PUSCH can be adjusted by varying the number of resources for the UCI.

[0007] Besides HARQ feedback, the PUCCH may also carry scheduling requests and / or channel state information (CSI) reports. Due to carrier aggregation scheduling, the use of Code Block Groups (CBGs) and / or Multiple-Input Multiple-Output (MIMO) layers, the number of UCI bits and thus, the amount of resources for PUCCH may vary. To optimize for different PUCCH payload sizes, different PUCCH formats (PF) were specified as summarized in the table below.

[0008] PUCCH format 4 (PF 4) differs from PUCCH format 3 (PF 3) in the use of orthogonal cover codes (OCC) and is used for FR2-2.

[0009] To minimize the UCI bits, a dynamic HARQ codebook is used by default, meaning that HARQ feedback resources are only allocated for down link (DL) transmissions that actually take place. If carrier aggregation and CBG transmission is used, the HARQ codebook size may become very large. If there are not enough PUCCH resources for simultaneous HARQ feedback and CSI transmission, the CSI is dropped.

[0010] When UCI is transmitted on PUSCH, up to two HARQ feedback bits are always punctured. If more HARQ feedback bits are transmitted on PUSCH, rate matching is used for the uplink data.

[0011] Since there is a probability that a UE misses a DCI / PDCCH carrying DL scheduling assignments, the UE would incorrectly calculate the HARQ codebook size. To solve this, downlink assignment index (DAI) counters are utilized in the DCI. The DAI field in the DCI indicates the amount of resources reserved for DL HARQ feedback. Thus, regardless of whether the device missed any previous scheduling assignments or not, the amount of resources, i.e. the expected count of HARQ feedback bits, to use for the DL HARQ feedback is known. The UE sets bit positions to “NACK” which correspond to the missed DCIs, e.g. missing DAI. Nevertheless, there is still an ambiguity as the gNB cannot distinguish whether a UE missed a DCI or a corresponding transport block, and usage of DAI comes with complexities in carrier aggregation scheduling on top of the use of Code Block Groups (CBGs) and MIMO layers, as these resources between individual carriers need to be coordinated.

[0012] The use of the counter DAI (cDAI) and total DAI (tDAI) in the DL DCI is illustrated in Figure 2 (a) and allows the UE to detect missed DCIs and determine the HARQ codebook size for UCI transmission to the network node. It should be noted that HARQ IDs in the example used in Figure 2 (a) are used on different carriers for the sake of simplicity only. Each carrier has its own set of HARQ processes and may thus use the same HARQ ID as another carrier. The DAI pair in narrow text in the first row denotes the actual cDAI / tDAI, while the DAI pair in bolded text assumes only 2 bits for the DAI transmission, and the cDAI / tDAI to be provided in the DCI is the actual cDAI / tDAI mod 4.

[0013] The DCI further informs the UE about the time offset between DCI reception and HARQ feedback transmission.

[0014] The UE provides the HARQ-FB as a bitmap. Based on the DAIs, the UE calculates the size of the HARQ-FB bitmap and the bitmap positions for the corresponding HARQ ACK / NACKs. For missed DCIs, the UE sets NACK. Thus, the network node cannot distinguish whether the UE had missed the DCI or whether it had been unable to decode the transport block.

[0015] Furthermore, if the gNB does not receive any HARQ feedback / UCI on PUCCH or PUSCH, in such a case, the gNB does not know whether the UE had missed the scheduling DCI or whether the UE transmitted HARQ feedback, which was however not detected by the gNB. Figure 2(b) shows HARQ feedback provided in the UCI. Another approach that addresses the ambiguity is the one-shot HARQ feedback request, which was introduced in the context of NR-U. It gives the gNB the possibility to request the UE to send HARQ feedback for all HARQ processes. Other common failures of the downlink HARQ protocol are that transmission errors of the PUCCH lead to flipping of the transmitted HARQ feedback, e.g. from NACK to ACK, i.e. a false positive, or from ACK to NACK, i.e. a false negative. False negatives will lead to unnecessary retransmissions and thus, inefficient resource usage, and false positives can be addressed by the acknowledged mode (AM) of the radio link control (RLC) protocol.

[0016] The slot timing between DL data transmission and HARQ feedback, denoted as KI, is determined based on the KI field in DCI. Kl=0 means that the HARQ-FB is provided in the same slot, Kl=l means that the HARQ-FB is provided in the next slot, etc.

[0017] For NR-U, a non-numerical KI value can be used, indicating that the network node has not yet decided when the UE shall send the HARQ-FB for a given HARQ process. Instead, the network node can, at a later point of time, request a “one-shot” HARQ feedback for all, active / non-active, HARQ processes. When the UE receives such a HARQ-FB request, it sets the HARQ-FB bits to ACK for successfully decoded transport blocks, and all others to NACK. The ACKs are only flushed when the UE receives a toggled New Data Indicator (NDI) for that HARQ process. As in legacy, the NACK may indicate to the network node that the UE either missed the DCI or that it unsuccessfully decoded the corresponding TB.

[0018] The radio link control (RLC) protocol, which resides on top of the HARQ protocol, in acknowledged mode (AM), is able to detect and correct HARQ residual errors. Therefore, RLC maintains its own state of which data packets are already successfully received. This is based on RLC status reporting from the receiver. Counters and timers are employed to poll, trigger and if needed retransmit RLC status reports and retransmit RLC data until reception success is ensured. RLC status reports are considered data in the HARQprotocol, meaning they undergo HARQ retransmissions in case of unsuccessful reception. The drawback of RLC retransmissions is increased latency.

[0019] There currently exist certain challenge(s). For example, for carrier aggregation, there is PUCCH overhead versus increased latency for PUCCH allocation due to scheduling dependency for primary and secondary cells (PCell / SCell(s)). The Size of PUCCH allocation depends on scheduling decisions on PCell / SCell(s) which results in varying PUCCH allocation size and increasing decoding error probability. There is ambiguity caused by missed DCI versus missed UL HARQ. RLC retransmissions due to feedback issues cause large delays, as RLC retransmissions are based on RLC timers, which are configured with delays allowing a certain number of more spectrally efficient HARQ retransmissions before triggering RLC retransmissions.SUMMARY

[0020] Certain aspects of the disclosure and their embodiments may provide solutions to these or other challenges.

[0021] In a communication system where a UE is triggered to report HARQ feedback over MAC, the size and the order of the feedback messages should be dependent on content. If all feedback messages can’t be sent in a given occasion, prioritization is needed. Rules for dropping a feedback message may also be needed. Different HARQ feedback messages may be prioritized based on time urgency of the feedback messages.

[0022] Therefore, it is an object of embodiments herein to provide a method for handling transmission of feedback messages in a communication system.

[0023] According to one aspect of embodiments herein, the object is achieved by a first node and method therein for handling transmission of one or multiple feedback messages related to one or multiple data receptions in a wireless communication system. The first node determines to send one or multiple feedback messages indicating status of one or multiple data receptions to a second node. The first node determines a priority or an order for the one or multiple feedback messages. The first node sends the one or multiple feedback messages based on the priority or order of the feedback messages on a data transmission channel to the second node, e.g. a physical layer Medium Access Control (Mac) data channel.

[0024] According to some embodiments herein, the first node may be a UE or radio access network node.

[0025] According to some embodiments herein, the one or multiple feedback messages may be sent in the same or different transmission occasions.

[0026] According to some embodiments herein, the priority or order of a feedback message may be determined between the multiple feedback messages or between a feedback message and other control and data transmissions.

[0027] According to some embodiments herein, the priority or order of the multiple feedback messages may be determined based on any one or a combination of the following:• transmitting times of the related data transmitted by the second node;• carrier index of a carrier carrying the related data transmitted by the second node;• the time since the related data transmission ended, or started;• reception status of the related data transmitted by the second node;• pending age of the feedback message;• a content of the related data transmitted by the second node;• explicit or implicit control information scheduling the related data transmissions;• available data transmission channel carrying the feedback messages;• granularities of the content of the feedback messages.

[0028] According to some embodiments herein, a content of a feedback message may be determined based on at least one of the priority of the feedback message and available data resources.

[0029] According to some embodiments herein, the feedback messages with lower priority may be split over multiple transmission occasions.

[0030] According to some embodiments herein, the granularity of the content of the feedback message may be dependent on transport block size and availability and priority of other data.

[0031] According to some embodiments herein, for indicating the reception status of a related data, the first node may generate a feedback message with a coarse granularity and / or a feedback message with a finer granularity.

[0032] According to some embodiments herein, for a transmission occasion, a feedback message with a coarse granularity may have higher priority than a feedback message with a finer granularity.

[0033] According to some embodiments herein, the feedback message with higher priority may be sent in multiple different transport blocks, while the feedback message with lower priority may be sent in a lower number of transport blocks.

[0034] Certain embodiments may provide one or more of technical advantage(s), such as faster HARQ retransmissions and less overhead.BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Examples of embodiments herein are described in more detail with reference to attached drawings in which:

[0036] Figure 1 is a schematic block diagram depicting 5G user-plane protocols;

[0037] Figure 2 (a) is a schematic block diagram depicting use of counter DAI and totalDAI;

[0038] Figure 2 (b) is a schematic block diagram depicting HARQ feedback provided inUCI;

[0039] Figure 3 is a schematic block diagram depicting a wireless communication system;

[0040] Figure 4 is a schematic block diagram depicting HARQ transmissions in TBs;

[0041] Figure 5 is a signaling flowchart depicting signal flow between a first and second radio nodes according to an embodiment herein;

[0042] Figure 6 (a)-(c) are schematic block diagrams showing examples of determining priority for feedback messages according to embodiment herein;

[0043] Figure 7 is a flowchart illustrating a method performed in a radio node according to an embodiment herein;

[0044] Figure 8 is a schematic block diagram illustrating an example embodiment of a network node; and

[0045] Figure 9 is a schematic block diagram illustrating an example embodiment of a communication device.DETAILED DESCRIPTION

[0046] It should be understood by the skilled in the art that “communication device” is a non-limiting term which means any terminal, wireless communication terminal, user equipment, Machine Type Communication (MTC) device, Device to Device (D2D) terminal, or node e.g. smart phone, laptop, mobile phone, sensor, relay, mobile tablets or even a small base station communicating within a cell.

[0047] The terms “communication device”, “wireless device”, “UE”, “user equipment”, “terminal equipment”, “wireless terminal” and “terminal” may be used interchangeably herein.

[0048] A network node may be a RAN node, a gNB, an eNB, an en-gNB, a ng-eNB, a gNB-CU, a gNB-CU-CP, a gNB-CU-UP, an eNB-CU, an eNB-CU-CP, an eNB-CU-UP, anlAB-node, an lAB-donor DU, an lAB-donor-CU, an IAB-DU, an IAB-MT, an O-CU, an O- CU-CP, an O-CU-UP, an O-DU, an O-RU, an O-eNB, a Non-Real Time RAN Intelligent Controller (Non-RT RIC), a Real-Time RAN Intelligent Controller (RT-RIC), an OAM node, a Core Network node / function, a Cloud-based network function, a Cloud-based centralized training node, a node hosting NR PDCP etc.

[0049] Research on 6G as the next generation of mobile communication system is ongoing. This disclosure relates to potential technical components of 6G communication system which are described utilizing existing definitions and descriptions according to 5G specifications.

[0050] Embodiments herein relate to communication networks in general. Figure 3 is a schematic overview depicting a communication network or system 300. The communication network 300 may be a wireless communication network comprising one or more RANs, and one or more CNs. The communication network 300 may use a number of different RATs, such as Wi-Fi, Long Term Evolution (LTE), LTE-Advanced, NR, Wideband Code Division Multiple Access (WCDMA), Global System for Mobile communications / enhanced Data rate for GSM Evolution (GSMZEDGE), Worldwide Interoperability for Microwave Access (WiMax), or Ultra Mobile Broadband (UMB), NR etc. just to mention a few possible implementations.

[0051] In the wireless communication network 300, one or more wireless communication devices 330, 331 such as a UE, a mobile station or a wireless terminal communicates via one or more Radio Access Networks (RAN) to one or more core networks (CN).

[0052] Network nodes operate in the wireless communication network 300 such as a first network node 311, a second network node 312. The first and second network nodes 311, 312 may be any of RAN node, such as gNB, eNB, en-gNB, ng-eNB, gNB etc. The first network node 311 provides radio coverage over a geographical area, a service area 11, which may also be referred to as a beam or a beam group where the group of beams is covering the service area of a first radio access technology (RAT), such as 5G, LTE, Wi-Fi or similar. The second network node 312 provides radio coverage over a geographical area, a service area 12, which may also be referred to as a beam or a beam group where the group of beams is covering the service area of a second radio access technology (RAT), such as 5G, LTE, Wi-Fi or similar. It should be noted that a network node may be a RAN node, a CN node or an OAM node.

[0053] The first / second network nodes 311 / 312 may be a transmission and reception point e.g. a radio access network node such as a Wireless Local Area Network (WLAN)access point or an Access Point Station (AP STA), an access controller, a base station, e.g. a radio base station such as a NodeB, a gNB, an evolved Node B (eNB, eNode B), a base transceiver station, a radio remote unit, an Access Point Base Station, a base station router, a transmission arrangement of a radio base station, a stand-alone access point or any other network unit capable of communicating with a wireless communication device within the service area served by the respective first / second network nodes 311 / 312 depending e.g. on the radio access technology and terminology used. The first and the second network nodes 311 / 312 may be referred to as a source and a target network node, respectively, and may communicate with the wireless communication device 330, 331 with Downlink (DL) transmissions to the wireless communication device 330, 331 and Uplink (UL) transmissions from the wireless communication device 330, 331.

[0054] The disclosure describes the operations in a UE or network node, referred as a first node, e.g. a UE 330 or a network node 311, configured or signaled to generate one or multiple HARQ feedback messages, related to one or multiple data receptions, and include these feedback messages in a transport block on a data channel. It also describes the actions in a second node, e.g. a network node 311 or a UE 330, receiving the HARQ feedback messages on the data-channel, dependent on the presence of a given feedback message.

[0055] Figure 4 shows an example HARQ transmissions between the first and second nodes using HARQ processes, where HARQ feedback messages, referred as HARQ-FB in the figure, are encapsulated in a data transport block and carried on a data channel. In this example, the HARQ-FB message is transmitted on slot n. The HARQ codebook size corresponds to the number of HARQ processes identified by the same bundle identity (ID) and sets the reception status in accordance as described for Fig. 2 (a).

[0056] Figure 5 shows a signal flowchart between the first and second nodes for HARQ request and HARQ-FB transmissions. The second node may send one or more requests containing Channel Information (CI) and HARQ transmissions carried in a data transport block, may also be denoted as data resources, to the first node on slots 0-2. The second node may send a CI containing HARQ-FB request and indication of HARQ association set to the first node, e.g. a bundle ID to determine the set of HARQ transmissions / processes.

[0057] The HARQ-FB may be transmitted autonomously by the first node using preconfigured or contention-based radio resources. The first radio node needs to include sufficient information so that the second radio node can associate the HARQ-FB with the corresponding data transmissions.

[0058] Alternatively, a control message from the second radio node to the first radio node may be included:• The control message schedules data resources carrying data and / or the HARQ-FB message.• The control message includes timing information and / or a bundle ID to define the HARQ transmissions to be associated with the HARQ-FB message.

[0059] Alternatively, the first radio node transmits the HARQ-FB message in accordance with the control message from the second node.

[0060] The transport blocks and signal flowchart shown in Figures 4-6 are applicable for DL, UL and side-link.

[0061] A method performed by a first node e.g. the network node 311 or the UE 330, for handling transmission of one or multiple feedback messages related to one or multiple data receptions in a wireless communication system 300 will be described with reference to Figure 7. The method comprises the following actions which may be performed in any suitable order.

[0062] Action 710

[0063] The first node (330 / 311) determines to send to a second node (311 / 330), one or multiple feedback messages indicating status of one or multiple data receptions. The first node (330 / 311) may receive a request from a second node (311 / 330) to send a feedback message to indicate reception status of one or multiple data transmitted by the second node (311 / 330). The first node (330 / 311) may, by configuration or specification, determine to send one or multiple feedback messages indicating reception status of one or multiple data transmitted by the second node (311 / 330).

[0064] Action 720

[0065] The first node (330 / 311) may generate one or multiple feedback messages based on the reception status of the one or more data transmitted by the second node (311 / 330). The feedback message may be acknowledgement ACK, no- acknowledgement NACK or missed. Alternatively, the first node (330 / 311) may generate one or multiple feedback messages that have been prioritized and fit them in the transmission. That is the Action 720 may happen after the following Action 730.

[0066] Action 730

[0067] When all feedback messages can’t be sent in a given transmission occasion, prioritization is needed. The first node (330 / 311) determines priority for one or multiple feedback messages.

[0068] In one embodiment, the first node (330 / 311) may, by configuration or specification, send an HARQ feedback message it has pending in order of age, so that an HARQ feedback message related to a data transmission that started first or ended first, is given the highest priority, and a later HARQ feedback message is appended dependent on if the data transmission carrying the feedback messages can fit more bits.

[0069] In some embodiments it is also the component carrier carrying the related data transmission, i.e. the related data transmitted by the second node (311 / 330), affecting the order of sending feedback messages. As an example, a feedback message may be prioritized based on carrier index of a carrier carrying the related data transmitted by the second node (311 / 330). Furthermore, the order of the carriers or carrier indices may depend on their utilized carrier frequency, subcarrier spacing, numerology or subframe duration. In this way, the prioritization for feedback message transmissions may be related to the expected transmission duration per carrier.

[0070] In some embodiments, an HARQ feedback message related to a data transmitted by the second node (311 / 330) is given lower priority, or discarded, if the time since the related data transmission ended, or started, is larger than a threshold.

[0071] In some embodiments, HARQ feedback prioritization is dependent on the decoding or reception status of the related data transmission. In some embodiments, the first node may prioritize sending a feedback message containing negative acknowledgement (NACK). This may be beneficial to speed up the retransmission of failed data. In other embodiments, the first node may prioritize sending a feedback message containing positive acknowledgement (ACK). This may be beneficial to avoid unnecessary retransmissions of already decoded or received data. In some embodiments, the prioritization of feedback message with ACK or NACK may depend also on the age of the feedback message, e.g. by prioritizing ACK if it has a delay larger than a threshold, else prioritize NACK.

[0072] In some embodiments, a feedback message may be prioritized based on the content of the related data transmission. As an example, an ACK for a successful decoding of a data transmission containing high priority data, such as signaling, control for higher layers such as radio link control (RLC) status report, or data on a high priority logical channel or data bearer, may be given higher priority than some other feedback messages. In someembodiments, a feedback message is prioritized based on explicit or implicit control information scheduling the related data transmission.

[0073] In some embodiments, the priority of a feedback message may also be impacted by what data channel it is allowed to use or to be mapped to for feedback message transmissions. For example, only feedback message with a given priority, due to content or age or other, may be allowed to be sent on a pre-allocated contention-based resource. In other examples, a control message may indicate what type or priority of feedback message can be mapped to a given data transmission carrying the feedback message. For example, only low priority feedback messages may be mapped to a channel with high expected Block Error Rate (BLER), since the delay may be bad due to retransmissions.

[0074] Transmission restrictions may be defined per logical channel to which a feedback message belongs to. For an example of a downlink data transmission, with feedback message sent in the uplink direction, these restrictions would thus be defined for downlink logical channels. Examples of such restrictions may be: allowance to send feedback messages on a certain carrier or serving cell, allowance to send on a certain numerology, subframe PUSCH duration, allowance to send on certain configured grant configuration or contention based resources, or certain PUSCH resources flagged with a prioritization index.

[0075] In some embodiments, the priority may not only affect the order between different feedback messages but also between a feedback message and other control and data transmissions. In some embodiments, higher priority HARQ feedback message may have higher priority than some control information, like buffer status reports. In other examples, lower priority feedback message may have lower priority than some logical channels for data.

[0076] In some embodiments, not only the priority but also the content of the HARQ feedback message may depend on priority and / or available data transport blocks i.e. data resources. As an example, the first node (330 / 311) may consider a basic feedback with high priority and provide a richer feedback format, for example containing more granular quality information or information divided over multiple code block groups, with lower priority, if there is room left in a transmission occasion. For example, information per code block or group of code blocks, information related to the estimated quality of the reception, information related to parts of the transmission with better or worse quality etc.

[0077] According to some embodiments herein, for indicating the reception status of a related data, the first node (330 / 311) may generate a feedback message with a coarse granularity and / or a feedback message with a finer granularity. That is, for a transmission occasion, there may be a higher priority feedback message with coarse granularity and alower priority feedback message with finer granularity. In some embodiments both feedback messages with different granularity are sent. In some embodiments, only the feedback message with coarse granularity is sent. So the coarse feedback message will be sent but the finer feedback message will be sent only if there is room for it. If there are only enough resources to send higher priority feedback messages, e.g. higher prioritized channel, the lower priority feedback messages may be in general transmitted later, but among the subsequent transmission occasions, the feedback message with coarse granularity will be prioritized over the feedback message with finer granularity. However, if there is not enough resources to provide both feedback messages with different granularity, but enough for the feedback message with fine granularity, then only the fine granularity feedback message is transmitted, and the feedback message with coarse granularity may be completely omitted or dropped as assuming that it does not add any additional information. So in some embodiments, only the feedback message with finer granularity is sent, if there is room for it instead of sending both.

[0078] Figures 6 (a)-(c) show some examples of determining priority for the feedback messages with different granularity and determining priority between the feedback messages with different granularity and other FB messages depending on available data resources. In Figure 6 (a), some FB messages with coarse granularity may have higher priority. In Figure 6 (b), some FB messages with coarse granularity and some FB messages with finer granularity may have higher priority. For examples, if a coarse feedback message covers {all ACK, all NACK, all MISSED, MIX}, e.g. 5 ACKs, but no information which of the 16 HARQ transmissions, e.g. 4 bits to encode values from 1-15, were ACKed, then the 5 ACKs indication may require 4 bits (value range 1-15) + 1 -bit indication to indicate coarse / fine FB, i.e. 5 bits in total, and the full HARQ codebook would only require 1 -bit indication to distinguish between coarse and fine, and the fine granular HARQ-FB would need 16 bits, i.e. 17 bits in total. That is a coarse FB has 5 bits and a fine granular FB has 17 bits. Let’s assume the radio resources that are remaining for HARQ-FB transmission is 18 bits. Thus, no room to transmit coarse AND fine FB messages, but the finer FB message should be sent to have efficient retransmissions. Then the first node may prioritize the fine granular feedback message with 17 bits rather than sending the coarse FB with 5 bits.

[0079] If there is room for 20 bits FB and there are 4 FB messages, i.e. if transmission on 4 carriers is used, the first node may try to squeeze in as many coarse FB messages, e.g. 4x5 bits =20 bits, as possible rather than sending a single fine granular FB message with 17 bits.

[0080] In Figure 6 (c), available data resources are used for FB messages with higher priority.

[0081] In some embodiments, a feedback message with higher priority may also be duplicated and the same information will be sent in multiple different transport blocks while a lower priority feedback message may be sent in a lower number of transport blocks, typically only 1. Multiple repetitions will reduce the BLER of the feedback messages.

[0082] Therefore, according to embodiments herein, the priori ty / order of the multiple feedback messages may be determined based on any one or a combination of the following:• transmitting times of a related data transmitted by the second node;• carrier index of a carrier carrying the related data transmitted by the second node;• the time since a related data transmission ended, or started;• reception status of a related data transmitted by the second node;• pending age of a feedback message;• a content of a related data transmitted by the second node;• explicit or implicit control information scheduling the related data transmissions;• available data transmission channel carrying the feedback messages;• granularities of the content of the feedback messages.

[0083] Action 740

[0084] The first node sends one or multiple feedback messages based on the priority or order of the feedback messages on a data transmission channel. Figure 4 shows an example where a feedback message is sent on the slot n of a data transmission channel.

[0085] The method described above may be performed by a UE or a network node, which is applicable for both DL and UL transmissions. To perform the method in the first network node, e.g. the network node 311, the network node 311 may comprise modules or functions as shown in Figure 8. The network node 311 may comprise a receiving module 810, a transmitting module 820, a determining module 830, a processing module 840, a memory 850 etc.

[0086] The network node 311 is configured to perform any one of the Actions 710-740 described above.

[0087] The network node 311 is configured to, by means of e.g. the determining module 830 being configured to, determine to send one or multiple feedback messages indicating status of one or multiple data receptions to a second node, i.e. UE 330.

[0088] The network node 311 is further configured to, by means of e.g. the determining module 830 being configured to, determine a priority or an order for the one or multiple feedback messages.

[0089] The network node 311 is further configured to, by means of e.g. the transmitting module 820 being configured to, send the one or multiple feedback messages based on the priority or order of the feedback messages on a data transmission channel to the second node UE 330.

[0090] The methods according to embodiments herein may be implemented through one or more processors, such as the processor 860 in the network node 311 together with computer program code for performing the functions and actions of the embodiments herein. The program code mentioned above may also be provided as a computer program product, for instance in the form of computer readable medium or a data carrier 880 carrying computer program code 870, as shown in Figure 8, for performing the embodiments herein when being loaded into the network node 311. One such carrier may be in the form of a CD ROM disc. It is however feasible with other data carriers such as a memory stick. The computer program code may furthermore be provided as pure program code on a server or a cloud and downloaded to the network node 311.

[0091] To perform the method in a communication device, e.g. UE 330, the UE 330 may comprise modules or functions as shown in Figure 9. The UE 330 may comprise a receiving module 910, a transmitting module 920, a determining module 930, a processing module 940, a memory 950 etc.

[0092] The UE 330 is configured to perform any one of the Actions 710-740 described above.

[0093] The UE 330 is configured to, by means of e.g. the determining module 930 being configured to, determine to send one or multiple feedback messages indicating status of one or multiple data receptions to the network node 311.

[0094] The UE 330 is further configured to, by means of e.g. the determining module 930 being configured to, determine a priority or an order for the one or multiple feedback messages.

[0095] The UE 330 is further configured to, by means of e.g. the transmitting module 920 being configured to, send the one or multiple feedback messages based on the priority or order of the feedback messages on a data transmission channel to the network node 311.The methods according to embodiments herein may be implemented through one or more processors, such as the processor 960 in the communication device UE 330 together with computer program code for performing the functions and actions of the embodiments herein. The program code mentioned above may also be provided as a computer program product, for instance in the form of computer readable medium or a data carrier 980 carrying computerprogram code 970, as shown in Figure 9, for performing the embodiments herein when being loaded into the communication device UE 330. One such carrier may be in the form of a CD ROM disc. It is however feasible with other data carriers such as a memory stick. The computer program code may furthermore be provided as pure program code on a server or a cloud and downloaded to the communication device UE 330.EXAMPLE EMBODIMENTS1. A method performed by a first node (UE330 / 311) for handling transmission of one or multiple feedback messages related to one or multiple data receptions in a wireless communication system (300), the method comprising: determining (710) to send one or multiple feedback messages indicating status of one or multiple data receptions to a second node (311 / UE330); generating (720) one or multiple feedback messages based on the status of the one or more data receptions; determining (730) a priority or an order for the one or multiple feedback messages; and sending (740) one or multiple feedback messages based on the priori ty / order of the feedback messages on a data transmission channel.2. The method according to embodiment 1, further comprising determining a size for the one or multiple feedback messages.3. The method according to any one of embodiments 1-2, wherein one or multiple feedback messages are sent in the same or different transmission occasions.4. The method according to any one of embodiments 1-3, wherein the priori ty / order of the multiple feedback messages is determined based on transmitting times of the related data transmissions.5. The method according to any one of embodiments 1-3, wherein the priori ty / order of the multiple feedback messages is determined based on carrier index of a carrier carrying the related data transmissions.6. The method according to any one of embodiments 1-3, wherein a feedback message is given lower priority, or discarded, if the time since the related data transmission ended, or started, is larger than a threshold.7. The method according to any one of embodiments 1-3, wherein the priority / order of a feedback message is determined based on a reception status of the related data transmission.8. The method according to embodiment 7, wherein the priority / order of a feedback message is determined based on whether feedback message contains a negative acknowledgement (NACK) or a positive acknowledgement (ACK).9. The method according to embodiment 8, wherein a feedback message containing negative acknowledgement (NACK) is determined to have a higher prioritization than other feedback messages.10. The method according to embodiment 8, wherein a feedback message containing positive acknowledgement (ACK) is determined to have a higher prioritization than other feedback messages.11. The method according to any one of embodiments 8-10, wherein the priority / order of a feedback message containing NACK or ACK is determined based on pending age of the feedback message.12. The method according to any one of embodiments 1-3, wherein the priority / order of a feedback message is determined based on a content of the related data transmission.13. The method according to any one of embodiments 1-3, wherein the priority / order of a feedback message is determined based on explicit or implicit control information scheduling the related data transmission.14. The method according to any one of embodiments 1-3, wherein the priority / order of a feedback message is determined based on available data transmission channel carrying the feedback message.15. The method according to any one of embodiments 1-14, wherein the priority / order of a feedback message is determined between the multiple feedback messages or between a feedback message and other control and data transmissions.16. The method according to any one of embodiments 1-15, wherein a content of a feedback message is determined based on priority and / or available data resources.17. The method according to any one of embodiments 1-16, wherein a content of feedback message is provided with a feedback format containing more granular quality.18. The method according to any one of embodiments 1-17, wherein the priority / order of a feedback message is determined based on granularity of the content of the feedback message.19. The method according to any one of embodiments 17-18, wherein the granularity of the content of the feedback message is dependent on transport block size and availability and priority of other data. 0. The method according to any one of embodiments 1-19, wherein generating one or multiple feedback messages comprises generating a feedback message with a coarse granularity and / or a feedback message with a finer granularity. 1. The method according to embodiment 20, wherein for a transmission occasion, a feedback message with a coarse granularity may have higher priority than a feedback message with a finer granularity.The method according to any one of embodiments 1-21, wherein the feedback messages with lower priority are split over multiple transmission occasions. The method according to any one of embodiments 1-22, wherein the feedback message with higher priority is sent in multiple different transport blocks, while the feedback message with lower priority is sent in a lower number of transport blocks. The method according to any one of embodiment 1-23, wherein the feedback message is an automatic repeat request, ARQ or a hybrid automatic repeat request, HARQ, message. The method according to any one of embodiment 1-24, wherein the first node is a UE or a radio access network node. A network node (311) configured to perform the method according to any one of the embodiments 1-24. A communication device (UE 330) configured to perform the method according to any one of the embodiments 1-24.

Claims

Claims1. A method performed by a first node (330 / 311) for handling transmission of one or multiple feedback messages related to one or multiple data receptions in a wireless communication system (300), the method comprising: determining (710) to send one or multiple feedback messages indicating status of one or multiple data receptions to a second node (311 / 330); determining (730) a priority or an order for the one or multiple feedback messages; and sending (740) the one or multiple feedback messages based on the priority or order of the feedback messages on a data transmission channel to the second node (311 / 330).

2. The method according to claim 1, wherein the one or more feedback messages are sent via physical layer Medium Access Control, Mac, data channel.

3. The method according to any one of claims 1-2, further comprising determining a size for the one or multiple feedback messages.

4. The method according to any one of claims 1-3, wherein the one or multiple feedback messages are sent in the same or different transmission occasions.

5. The method according to any one of claims 1-4, wherein the priority or order of the one or multiple feedback messages is determined based on transmitting times of the related data transmitted by the second node (311, 330).

6. The method according to any one of claims 1-4, wherein the priority or order of the one or more multiple feedback messages is determined based on carrier index of a carrier carrying the related data transmitted by the second node (311, 330).

7. The method according to any one of claims 1-4, wherein a feedback message is given a lower priority, or discarded, if the time since the related data transmission ended, or started, is larger than a threshold.

8. The method according to any one of claims 1-4, wherein the priority or order of a feedback message is determined based on a reception status of the related data transmitted by the second node (311, 330).

9. The method according to claim 8, wherein the priority or order of a feedback message is determined based on whether the feedback message contains a negative acknowledgement (NACK) or a positive acknowledgement (ACK).

10. The method according to claim 9, wherein the priority or order of a feedback message containing NACK or ACK is determined based on pending age of the feedback message.

11. The method according to any one of claims 1-4, wherein the priority or order of a feedback message is determined based on a content of the related data transmitted by the second node (311, 330).

12. The method according to any one of claims 1-4, wherein the priority or order of a feedback message is determined based on explicit or implicit control information scheduling the related data transmission.

13. The method according to any one of claims 1-4, wherein the priority or order of a feedback message is determined based on available data transmission channel carrying the feedback message.

14. The method according to any one of claims 1-4, wherein the priority or order of a feedback message is determined based on what data channel the feedback message is allowed to use or to be mapped to for the feedback message transmission.

15. The method according to any one of claims 1-14, wherein the priority or order of a feedback message is determined between the multiple feedback messages or between a feedback message and other control and data transmissions.

16. The method according to any one of claims 1-15, wherein a content of a feedback message is determined based on at least one of the priority of the feedback message and available data resources.

17. The method according to any one of claims 1-16, wherein a content of a feedback message with higher priority is provided with a feedback format containing more granular quality information or information divided over multiple code block groups than a feedback message with lower priority.

18. The method according to any one of claims 1-17, wherein the priority or order of a feedback message is determined based on granularity of the content of the feedback message.

19. The method according to any one of claims 17-18, wherein the granularity of the content of the feedback message is dependent on transport block size and availability and priority of other data.

20. The method according to any one of claims 1-19, wherein generating one or multiple feedback messages comprises generating at least one of a feedback message with a coarse granularity and a feedback message with a finer granularity.

21. The method according to claim 20, wherein for a transmission occasion, a feedback message with a coarse granularity has a higher priority than a feedback message with a finer granularity.

22. The method according to claim 21, wherein for a transmission occasion, if the available data sources are not enough for both feedback messages, only the feedback message with finer granularity is sent.

23. The method according to any one of claims 1-22, wherein the feedback messages with lower priority are split over multiple transmission occasions.

24. The method according to any one of claims 1-23, wherein the feedback message with higher priority is sent in multiple different transport blocks, while the feedback message with lower priority is sent in a lower number of transport blocks.

25. The method according to any one of claims 1-24, wherein the feedback message is an automatic repeat request, ARQ or a hybrid automatic repeat request, HARQ, message.

26. The method according to any one of claim 1-25, wherein the first node is a UE (330, 331) or a radio access network node (311, 312).

27. A network node (311) for handling transmission of one or multiple feedback messages related to one or multiple data receptions in a wireless communication system (300), the network node (311) being configured to: determine to send one or multiple feedback messages indicating status of one or multiple data receptions to a second node (330); determine a priority or an order for the one or multiple feedback messages; and send the one or multiple feedback messages based on the priority or order of the feedback messages on a data transmission channel to the second node (330).

28. The network node (311) according to claim 27 configured to perform the method according to any one of the claims 2-25.

29. A communication device (330) for handling transmission of one or multiple feedback messages related to one or multiple data receptions in a wireless communication system (300), the communication device (330) being configured to: determine to send one or multiple feedback messages indicating status of one or multiple data receptions to a second node (311); determine a priority or an order for the one or multiple feedback messages; and send the one or multiple feedback messages based on the priority or order of the feedback messages on a data transmission channel to the second node (331).

30. The communication device (330) according to claim 29 configured to perform the method according to any one of the claims 2-25.

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