WO2024096769A1

WO2024096769A1 - Methods, devices, computer programs and computer program products for reducing feedback signalling in a wireless communications system

Info

Publication number: WO2024096769A1
Application number: PCT/SE2022/051005
Authority: WO
Inventors: Robert Baldemair; Mattias Frenne; Qiang Zhang; Erik Eriksson
Original assignee: Telefonaktiebolaget Lm Ericsson (Publ)
Priority date: 2022-11-02
Filing date: 2022-11-02
Publication date: 2024-05-10

Abstract

Methods are disclosed for reducing feedback signalling in a wireless communications system. A method is performed in a scheduling device and comprises dynamically selecting at least a first and a second dimension for use in scheduling of feedback bits, the at least first and second dimensions selected at least among: time dimension, frequency dimension and spatial dimension, and dynamically controlling bundling of the feedback bits from one or more data units according to the selected at least first and second dimensions. A scheduling device is also provided. A method in a user device and a user device are also provided.

Description

Methods, devices, computer programs and computer program products for reducing feedback signalling in a wireless communications system

TECHNICAL FIELD

The technology disclosed herein relates generally to the field of wireless communications systems, and in particular to methods, devices, computer programs and computer program products for reducing feedback signalling in a wireless communications system.

BACKGROUND

Wireless communications networks use channel coding to improve the robustness of a transmission. A channel code operates on a block of information bits and produces a block of coded bits. This is called a code block. Often a single code block is not visible to higher layers, instead multiple code blocks are grouped to form code block bundles (CBBs), code block groups (CBGs), or transport blocks (TBs). Another reason to keep the size of the actual code block reasonably small is to limit encoding and decoding complexity. This maybe important in, for instance, 5G New Radio (NR), wherein the maximum information code block size is around 8k. In order to enable error detection, information bits can be concatenated with a cyclic redundancy check (CRC) which is encoded together with the information bits.

The receiver tries to decode the coded bits to extract information bits. If a CRC has been attached, the receiver also performs a CRC check to verify correct decoding. If the receiver determines that a transmission was decoded wrongly (e.g., based on the CRC check failing) it transmits a Not Acknowledge (NACK) message to the transmitter for requesting a re-transmission; in case of successful decoding an Acknowledgement (ACK) is sent.

ACK and NACK bits, often called Hybrid automatic repeat request (HARQ) feedback or HARQ-ACK bits, can be generated per code block or per CBB/ CBG/TB, in the latter case the CBB/ CBG/TB-HARQ feedback is the logical AND of the individual code block HARQ feedback bits (assuming ACK=i and NACK=o) which is also called HARQ-ACK bundling. The motivation is that the error events of the code blocks are correlated, hence, if one code block is in error, there is in some cases a high probability that also other code blocks in the same CBG, CBB, or TB are in error, hence signalling overhead can be reduced by introducing such bundling.

In prior art systems, such as Long-Term Evolution (LTE) and NR, bundling is performed across multiple transport blocks on the same carrier (time-domain bundling) or across code blocks transmitted on multiple spatial layers (spatial bundling).

In new systems, such as 6G and later releases of 5G/NR, a transmission scheduled by a single Downlink Control Information (DCI) feedback may span from very short transmissions (few symbols) to very long (many symbols), from a fraction of a carrier bandwidth to many carriers, and from one spatial layer to many spatial layers. There is thus a vast space of different scheduling configurations for transmission of feedback information, and this requires the feedback signalling to be efficient.

SUMMARY

An objective of embodiments herein is to address and improve various aspects for feedback signalling in wireless communications systems. A particular objective of the disclosed embodiments is to reduce the amount of feedback signalling. Another objective of the disclosed embodiments is to enable an efficient feedback signalling. These objectives and others are achieved by the methods, devices, computer programs and computer program products according to the appended independent claims, and by the embodiments according to the dependent claims.

These objectives and others are accomplished by introducing dynamic selection of dimensions used in feedback scheduling and dynamic control of bundling of the feedback accordingly.

According to a first aspect there is presented a method for reducing feedback signalling in a wireless communications system. The method is performed in a scheduling device and comprises dynamically selecting at least a first and a second dimension for use in scheduling of feedback bits. The at least first and second dimensions are selected at least among: time dimension, frequency dimension and spatial dimension. The method comprises to dynamically control bundling of the feedback bits from one or more data units according to the selected at least first and second dimensions.

According to a second aspect there is presented a computer program for reducing feedback signalling in a wireless communications system. The computer program comprises computer code which, when run on processing circuitry of a scheduling device, causes the scheduling device to perform a method according to the first aspect.

According to a third aspect there is presented a computer program product comprising a computer program as above, and a computer readable storage medium on which the computer program is stored.

According to a fourth aspect there is presented a scheduling device for reducing feedback signalling in a wireless communications system. The scheduling device is configured to dynamically select at least a first and a second dimension for use in scheduling of feedback bits, wherein the at least first and second dimensions are selected at least among: time dimension, frequency dimension and spatial dimension. The scheduling device is further configured to dynamically control bundling of the feedback bits from one or more data units according to the selected at least first and second dimensions.

According to a fifth aspect there is presented a method for reducing feedback signalling in a wireless communications system. The method is performed in a user device and comprises receiving, from a scheduling device, control information comprising a dynamic bundling configuration for uplink feedback. The method further comprises transmitting, uplink feedback according to the received dynamic bundling configuration.

According to a sixth aspect there is presented a computer program for reducing feedback signalling in a wireless communications system. The computer program comprises computer code which, when run on processing circuitry of a user device, causes the user device to perform a method according to the fifth aspect. According to a seventh aspect there is presented a computer program product comprising a computer program as above, and a computer readable storage medium on which the computer program is stored.

According to an eight aspect there is presented a user device for reducing feedback signalling in a wireless communications system. The user device is configured to receive, from a scheduling device, control information comprising a dynamic bundling configuration for uplink feedback. The method further comprises transmitting uplink feedback according to the received dynamic bundling configuration.

Advantageously, these aspects enable a HARQ feedback reduction and thus HARQ- ACK reporting coverage enhancement across very different scheduling configurations, such as, for instance, long and narrow or short and wide transmissions. These aspects enable the wireless communications network to optimize the resources depending on channel conditions etc.

Other objectives, features and advantages of the enclosed embodiments will be apparent from the following detailed disclosure, from the attached dependent claims as well as from the drawings.

Generally, all terms used in the claims are to be interpreted according to their ordinary meaning in the technical field, unless explicitly defined otherwise herein. All references to "a/an/the element, apparatus, component, means, module, action, etc." are to be interpreted openly as referring to at least one instance of the element, apparatus, component, means, module, action, etc., unless explicitly stated otherwise. The actions of any method disclosed herein do not have to be performed in the exact order disclosed, unless explicitly stated.

BRIEF DESCRIPTION OF THE DRAWINGS

The inventive concept is now described, by way of example, with reference to the accompanying drawings, in which:

Figures la, lb, ic, id and le illustrate exemplary scheduling configurations according to embodiments;

Figure 2 illustrates an example of bundling of feedback bits; Figures 3a, 3b and 3c illustrate exemplary transmission scenarios;

Figure 4 illustrates a wireless communications system.

Figure 5 is a flowchart of a method according to embodiments;

Fig. 6 is a schematic diagram showing functional units of a scheduling device according to an embodiment;

Fig. 7 is a schematic diagram showing functional modules of a scheduling device according to an embodiment;

Fig. 8 shows one example of a computer program product comprising computer readable means according to an embodiment.

Figure 9 is a flowchart of a method according to embodiments;

Fig. 10 is a schematic diagram showing functional units of a user device according to an embodiment;

Fig. 11 is a schematic diagram showing functional modules of a second device according to an embodiment; and

Fig. 12 shows one example of a computer program product comprising computer readable means according to an embodiment.

DETAILED DESCRIPTION

The inventive concept will now be described more fully hereinafter with reference to the accompanying drawings, in which certain embodiments of the inventive concept are shown. This inventive concept may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided by way of example so that this disclosure will be thorough and complete, and will fully convey the scope of the inventive concept to those skilled in the art. Like numbers refer to like elements throughout the description. Any action or feature illustrated by dashed lines should be regarded as optional. As noted in the background section, in new systems, such as 6G and later releases of 5G, a transmission scheduled by a single DCI feedback may span from very short transmissions, comprising few symbols, to very long, comprising many symbols. Further, the scheduled transmission may span from a fraction of a carrier bandwidth to many carriers, and from one spatial layer to many spatial layers. This vast space of scheduling configurations requires a fixed bundling scheme, which is often very limiting. For instance, bundling across multiple transport blocks in time-domain does not help in reducing feedback for short but very wide transmissions. From this, it is realized that there is a need for improvement of feedback signalling.

Briefly, in contrast to the existing methods, the present disclosure provides, in various embodiments, methods, devices, computer programs, and computer program products for flexible feedback (e.g., HARQ-ACK) bundling where order of bundling (e.g., first time, then carriers or first carriers, then time) and/or bundling granularity per dimension can be controlled dynamically.

In future wireless systems, , such as for instance, later releases of 5G, 6G, it may be envisioned that a single DCI can schedule multiple carriers and/or transmissions lasting over a long time period and/or across multiple transmission points (TRP). Such transmissions may contain many individual code blocks, arranged either along time across different symbols for long transmissions, along frequency across multiple carriers for wide transmissions, across spatial layers for high-rank Multiple Input, Multiple Output (MIMO) transmissions, where different layers are transmitted from same or different TRPs, and also within a carrier and symbol.

In principle, one HARQ feedback bit may be generated per code block. Also, even multiple HARQ feedback bits may be generated per code block in case a more detailed and advanced HARQ feedback scheme is introduced. Reporting HARQ feedback on code block level may lead to an excessive amount of HARQ feedback bits and thus high overhead in the uplink (UL) or, more generally, reverse link from data receiver to transmitter, e.g., in sidelink transmissions. This also impacts the user equipment (UE) coverage to report these bits.

A fixed bundling rule cannot reduce this feedback for all possible scheduling configurations. For example, a rule that bundles all HARQ feedback bits within a carrier within a certain time-window does not help if the transmission only stretches over one symbol but many carriers.

In addition, the wireless communications network (also denoted simply network in the following) may have rather detailed knowledge of the channel from the TRP or the multiple TRPs that is/ are used for transmitting data to the UE. In particular, channel reciprocity-based transmission can be used in Time Division Duplex (TDD), and the network can have a good estimate of the correlation of the fading across time, frequency, space (spatial layers and across TRPs). This correlation dynamically changes when the UE moves around in the network. If two code blocks are transmitted over two channels that the network has measured (e.g., in uplink) to be highly correlated, it is rather safe to bundle the HARQ-ACK bits together into a single bit. If a fixed (or semi static) bundling rule is adopted as in current systems, the configuration needs to assume the worst case (lower correlation) and cannot utilize the bundling efficiently.

In accordance with the present teachings, the bundling is dynamically configurable. The knowledge from the uplink measurements may, for instance, be used. One particular example is to dynamically control the order across which dimensions HARQ-ACK bundling is applied. The dimensions may, for instance, be symbols (time), carriers (frequency), spatial layers/TRPs, HARQ bits within a carrier and symbol, transmissions scheduled by different DCIs.

Another example is to dynamically indicate a bundling granularity for a single or multiple dimensions. Such bundling granularity may be defined as how many HARQ feedback bits should be bundled into a single bit. The control information on how to configure the bundling could, for instance, be explicitly included in the DCI, it could follow from other parameters of the scheduling (especially time, frequency, and MIMO parameters, how many DCIs), or it could follow from the DCI format. In particular, the DCI format may be used if certain DCI formats are restricted to certain scheduling configurations, e.g., when a DCI can only schedule a single carrier, the bundling should be done across symbols and/or spatial layers. Naturally a combination of different signalling mechanism is also possible; for instance a few different bundling configurations are configured semi-statically with Radio Resource Control (RRC) and are dynamically selected (and possibly complemented) with DCI signalling.

Figs, la - le show scheduling configurations and examples of associated two- dimensional bundling rules. All examples share the available UL feedback size of 4 bits, although it should be noted that other sizes may be used as well. Each square with thin borders indicates a data unit (e.g., code block or code blocks within a carrier and symbol) that produces 1 HARQ feedback bit. Rectangular with bold borders are bundling units.

Fig. la shows an example where the feedback transmission occupies a single carrier (y-axis) over 8 symbols (x-axis). In order to reduce the number of feedback bits from 8 bits to the available UL feedback size of 4 bits, two HARQ feedback bits must be bundled across symbols (i.e., into the four bundling units shown in bold). Thus, bundling is first applied across symbols, and the determined bundling configuration is then (t,f)=(2,i), wherein t is time and f is frequency.

Fig. ib shows an example where 8 data units are scheduled but in this example across carriers. The HARQ feedback bits from 2 data units must, as in the previous example, be bundled to obtain the required compression. In this case the bundling is made across carriers (i.e., bundling is first applied across carriers). Thus, the determined bundling configuration is (t,f)=(i,2).

Fig. ic and id show examples where 64 data units are scheduled. Example ic) applies bundling of 4 symbols and 4 carriers (t, f) = (4, 4), while example id) applies bundling across 8 symbols and 2 carriers, (t, f) = (8, 2). In examples la) and ib) the scheduling configuration together with the UL feedback size determines the bundling configuration, although the UL feedback size alone would be sufficient to determine time-first bundling or frequency-first bundling. In contrast, additional information is needed for examples ic) and id). In example ic) equal bundling across dimensions could, for instance, be configured. Equal bundling may, for instance, be that equally many bundles are generated across each dimension or that the bundle size in each dimension is equal. In contrast, in example id) symbol -heavy bundling is configured. In this example, a bundle is four times as strong in symbol dimension as in carrier dimension. Fig. le shows a configuration comprising bundling first across symbols with bundling size (t)=(8). The bundling size in carrier-dimensions then follows automatically: in the example e) it follows that bundling needs to be applied across 3 carriers to fit the UL feedback size of 4 bits.

Bundling across carriers could for example be useful if a very wide transmission bandwidth is available, but due to implementation reasons the wide bandwidth is realized by multiple carriers, e.g., 800 MHz realized by 4 carriers each 200 MHz wide.

In the above examples the receiver knows the UL feedback size together with some bundling instructions, such as, for example the order of bundling, how heavy to bundle in a dimension (e.g., numerical values or no bundling, medium bundling, bundling across complete dimension), etc.. The UL feedback size may, for instance, follow from the DCI, implicitly from the UL grant, be configured, etc. Sometimes it may not be possible to compress the HARQ feedback to exactly match the UL feedback size, e.g., if the determined bundle size does not evenly divide the number of data units. In such cases, one or some bundles may have another size, e.g., a last bundle is extended to contain HARQ feedback from all remaining data units. Alternatively, bundling is performed such that the bundled HARQ feedback size will be equal to or smaller than the indicated UL feedback size and some padding (e.g., zero padding) is applied when needed.

Still another example is to deduce the bundling granularity, e.g., HARQ feedback, from how many data units should be bundled across each dimension (e.g., carrier and symbols). In Figure 1, example id), this information would be (t,f) =(8,2) which means bundling across 8 symbols and 2 carriers. The feedback size would in this case be determined based on the scheduling configuration together with the bundling configuration.

Yet another possibility to configure bundling is to specify how many bundle units one would like to have in each dimension, e.g., instead of specifying (t,f) =(8,2) in example d) of Figure 1 one could specify (#t_bundles,#f_bundles)=(i,4). The total number of HARQ feedback bits may be limited by the uplink coverage; the worse the coverage is, the fewer feedback bits can be used. However, even in cases wherein the coverage is good, one might still want to reduce the uplink feedback, particularly if such reduction does not degrade the performance much. If it is known that there is a strong correlation of data units along a certain dimension, the bundling could be strengthened across this dimension. There are thus many ways to perform the bundling.

In the various examples so far, bundling has been done across two dimensions, i.e., symbols and carriers. In addition to, or instead of, any of these dimensions other dimensions may be considered and used. A few particular examples on this comprise bundling across spatial layers, transmissions from two or more TRPs, or bundling within a carrier.

Fig. 2 illustrates an example of bundling of feedback bits. In Fig. 2 black circles indicate code blocks within a carrier and symbol. For simplicity, the same amount of code blocks is depicted for each carrier and symbol, although it is noted that different values would also be possible and likely to occur. First, bundling is applied across code blocks within a carrier and symbol. Subsequently bundling is applied across other dimensions, e.g., across symbols and carriers using bundling configuration (t,f)=(₄,4)

Various embodiments have been described, wherein data units from which HARQ feedback bits are bundled are part of a single assignment scheduled by a single DCI. It is noted that in another set of embodiments, this can be relaxed to include data units belonging to different assignments scheduled by multiple DCIs, e.g., transmissions occurring at different times or with carriers or at spatial layers/TRPs scheduled by individual DCIs.

Figures 3a, 3b and 3c illustrate exemplary transmission scenarios, which will be described next. In these figures the upper line illustrates the actions in a base station or an access point or the like, while the bottom line illustrates the actions in the UE or other wireless device.

In Fig. 3a, illustrating a first example, a first DCI, denoted DCIi, schedules a data transmission comprising multiple data units (DU): DU1. DU2. A second DCI, denoted DCI2, schedules uplink feedback (UL FB) for the data transmission. The bundling configuration is, at least partly, contained in DCI2 but may also be contained in scheduling information in DCIi and in RRC configuration. In Fig. 3b, illustrating a second example, DCIi and DCI2 schedule data transmission containing multiple data units: DU1, DU2, DU3. DCI3 schedules UL FB for both data transmissions (i.e., DU1, DU2, DU3). The bundling configuration is, at least partly, contained in DCI3 but may also be contained in scheduling information in DCIi, DCI2 and in RRC configuration.

In Fig. 3c, illustrating a third example, DCIi and DCI2 schedule data transmissions containing multiple data units (DU). DCI2 also schedules UL FB for both data transmissions (DU1, DU2 and DU3, respectively). The bundling configuration is, at least partly, contained in DCI2 but may also be contained in scheduling information in DCIi and in RRC configuration.

Fig. 4 illustrates highly schematically a wireless communications system 10, implementing any wireless communication technology, such as e.g., 5G or 6G. A method 50, in various embodiments, is described next with reference to figure 4, which method 50 maybe implemented in, for instance, a scheduler 14 of a base station 12, e.g., gNodeB (or gNB) or a base station supporting future 6G. A number of wireless devices 16, e.g., user devices (UEs), move around in the wireless communications system. The configuration of the bundling may typically be implemented on the base station side, while the execution of the bundling is made on the UE side. However, in, for instance, sidelinks, the transmitter of the data units maybe the part performing the configuration, and the receiver executing the bundling. The wireless communications system 10 maybe a cellular network, i.e., a radio network comprising cells. Each such cell may comprise a base station, as is well known. In other embodiments, the wireless communications system 10 is a cell-free type of system, i.e., where the system is not divided into regions (e.g., cells). Such cell-free type of wireless network may comprise antenna processing units (APUs) and central processing units (CPUs), wherein the APUs serve users that they reach, and each user may thus be served by one or more APUs. As a particular example, cell-free massive Multiple-input, Multiple Output (MIMO) can be mentioned. Such cell-free massive MIMO comprises access points (APs) deployed over the coverage area and serving the surrounding users. A central process controls them all, and as the APs serve all reachable users, there are no cell boundaries (hence “cell-free”). Fig. 5 is a flowchart of various embodiments of a method 50 for reducing feedback signalling in a wireless communications system. The method 50 maybe performed in a scheduling device 14, such as, for instance, a scheduler in the wireless communications system 10. The method 50 comprises dynamically selecting 52 at least a first and a second dimension for use in scheduling of feedback bits. The at least first and second dimensions are selected at least among: time dimension, frequency dimension and spatial dimension. For instance, the scheduling device 14 may schedule a first DCI for data transmissions comprising multiple data units. The first DCI may also comprise control information for scheduling uplink feedback. It is also noted that still further dimensions could be selected among, such as across transmission points, data units within a carrier and symbol.

The method 50 comprises dynamically controlling 54 bundling of the feedback bits from one or more data units according to the selected at least first and second dimensions. The dynamic control 54 may comprise providing instructions to a base station to signal a resulting bundling configuration to a wireless device 16. The dynamic control may comprise determining bundling size per dimension, determine order of dimension, etc. The method 50 provides a number of advantages. For instance, the method 50 enables, for instance, HARQ feedback reduction and thus HARQ-ACK reporting coverage enhancement across very different scheduling configurations, e.g., long and narrow or short and wide transmissions. It enables for the network to optimize the resources depending on, for instance, channel conditions etc.

In an embodiment, the dynamic controlling 54 comprises dynamically controlling an order in which the at least first and second dimensions of the feedback bundling is applied. In another embodiment, the dynamic controlling 54 comprises dynamically indicating bundling granularity for one or more of the at least first and second dimensions.

The method 50 may thus involve bundling feedback (e.g., HARQ-ACK) from multiple encoded blocks that are mapped across different dimensions, e.g., across symbols (time), carriers (frequency), spatial layers, etc. The bundling granularity per dimension can be controlled dynamically, for instance to enable a size reduction of HARQ feedback via bundling for a wide range of scheduling configuration. For example, the DCI that schedules e.g., the downlink data (i.e., Physical Downlink Shared Channel, PDSCH), or that requests the HARQ-ACK feedback, also provides the bundling order. The bundling order may, for instance, be first across symbols, then across carriers and/or multi-dimensional bundle size, i.e., across how many HARQ feedback bits in each dimension should be bundled.

In a first set of embodiments, the method 50 comprises scheduling, by multiple DCIs, bundled feedback bits as part of different transmissions.

In a second set of embodiments, different than the above first set, the method 50 comprises scheduling, by a single Downlink Control Information, DCI, the bundled feedback bits. It is noted that the DCI may schedule the bundled feedback or data units.

In variations of the second set of embodiments, the transmissions occur at different times, or at different carriers, or at different spatial layers or at different transmission points.

In still other embodiments, the method comprises scheduling, by a single DCI, the bundled feedback bits as part of multiple transmissions. In still further embodiments, the method comprises scheduling, by multiple DCIs, bundled feedback bits as a single transmission.

In various embodiments, one or more DCIs may schedule the data units. The DCI(s) may also include the scheduling of uplink feedback.

It thus realized that the method maybe implemented in many different ways, e.g., depending on the particular use case and/ or circumstances. The embodiments enable numerous variations on scheduling: one DCI may schedule one feedback transmission, or multiple DCIs may schedule multiple feedback transmissions; one or multiple DCIS may schedule data units.

In various embodiments, the dynamic controlling 54 comprises configuring a set of bundling configurations semi-statically with Radio Resource Control, RRC, and dynamically selecting the bundling configurations using DCI signalling. In various embodiments, the data unit is one of: a code block, a code block group, a transport block and a code block bundle. It is noted that still other formats may be used.

In various embodiments, the feedback comprises one or more of: Hybrid Automatic Repeat Request acknowledgment (HARQ - ACK) and Hybrid Automatic Repeat Request negative acknowledgment (HARQ - NACK).

In various embodiments, the wireless communications system is one of: a Long Term Evolution (LTE) system, 5G New Radio or 6G.

In various embodiments, the scheduling device 14 is a scheduling device, in an access point, a base station or a gNB.

A scheduling device 14 is also disclosed, suitable for implementing the described method. The scheduling device 14 is used for reducing feedback signalling in a wireless communications system and is configured to dynamically select at least a first and a second dimension for use in scheduling of feedback bits, wherein the at least first and second dimensions selected at least among: time dimension, frequency dimension and spatial dimension. As noted earlier, the dimensions may be selected in various different ways.

The scheduling device 14 is further configured to dynamically control bundling of the feedback bits from one or more data units according to the selected at least first and second dimensions. The scheduling device 14 provides the advantages stated earlier in relation to the method that it implements.

In an embodiment, the scheduling device 14 is configured to dynamically control an order in which the at least first and second dimensions of the feedback bundling is applied.

In some embodiments, the scheduling device is configured to dynamically indicate bundling granularity for one or more of the at least first and second dimensions.

In various embodiments, the scheduling device 14 is configured to schedule, by a single Downlink Control Information, DCI, the bundled feedback bits or data units. In variations of the above set of embodiments, the transmissions occur at different times, or at different carriers, or at different spatial layers or at different transmission points scheduled by individual DCIs.

In a set of embodiments different to the above, the scheduling device 14 is configured to schedule, by multiple DCIs, bundled feedback bits or data units in different transmissions.

In various embodiments, the scheduling device 14 is configured to dynamically control by configuring a set of bundling configurations semi-statically with Radio Resource Control, RRC, and dynamically select the bundling configurations using DCI signalling.

In various embodiments, the data unit is one of: a code block, a code block group, a transport block and a code block bundle.

In various embodiments, the feedback comprises at least one of: Hybrid Automatic Repeat Request acknowledgment (HARQ - ACK) and Hybrid Automatic Repeat Request negative acknowledgment (HARQ - NACK).

In various embodiments, the wireless communications system is one of: a Long Term Evolution (LTE) system, implementing Multiple Input, Multiple Output (MIMO) time-division duplex operation, 5G New Radio or 6G.

In various embodiments, the scheduling device 14 is, for instance, a module or unit comprising circuitry adapted for implementing the herein disclosed features. The scheduling device 14 may, e.g., be located in an access point, a gNB or a future base station for 6G.

Fig. 6 schematically illustrates, in terms of a number of functional units, the components of a scheduling device 14 according to an embodiment. Processing circuitry no is provided using any combination of one or more of a suitable central processing unit (CPU), multiprocessor, microcontroller, digital signal processor (DSP), etc., capable of executing software instructions stored in a computer program product 330 (as in Fig. 8), e.g., in the form of a storage medium 130. The processing circuitry no may further be provided as at least one application specific integrated circuit (ASIC), or field programmable gate array (FPGA). Particularly, the processing circuitry no is configured to cause the scheduling device 14 to perform a set of operations, or actions, as disclosed above. For example, the storage medium 130 may store the set of operations, and the processing circuitry 110 maybe configured to retrieve the set of operations from the storage medium 130 to cause the scheduling device 14 to perform the set of operations. The set of operations maybe provided as a set of executable instructions. The processing circuitry 110 is thereby arranged to execute methods as herein disclosed.

The storage medium 130 may also comprise persistent storage, which, for example, can be any single one or combination of magnetic memory, optical memory, solid state memory or even remotely mounted memory.

The scheduling device 14 may further comprise a communications interface 120 for communications with other entities, functions, nodes, and devices, over suitable interfaces. As such the communications interface 120 may comprise one or more transmitters and receivers, comprising analogue and digital components.

The processing circuitry no controls the general operation of the scheduling device 14 e.g., by sending data and control signals to the communications interface 120 and the storage medium 130, by receiving data and reports from the communications interface 120, and by retrieving data and instructions from the storage medium 130. Other components, as well as the related functionality, of the scheduling device 14 are omitted in order not to obscure the concepts presented herein.

Fig. 7 schematically illustrates, in terms of a number of functional modules, the components of a scheduling device 14 according to an embodiment. The scheduling device 14 of Fig. 7 comprises a number of functional modules; a dynamic selection module 210 configured to dynamically select at least a first and a second dimension for use in scheduling of feedback bits, the at least first and second dimensions selected at least among: time dimension, frequency dimension and spatial dimension, and a dynamic control module 220 configured to bundle the feedback bits from one or more data units according to the selected at least first and second dimensions. In general terms, each functional module 210, 220 maybe implemented in hardware or in software. Preferably, one or more or all functional modules 210, 220 maybe implemented by the processing circuitry no, possibly in cooperation with the communications interface 120 and the storage medium 130. The processing circuitry no may thus be arranged to from the storage medium 130 fetch instructions as provided by a functional module 210, 220 and to execute these instructions, thereby performing any actions of the scheduling device 14 as disclosed herein.

Fig. 8 shows one example of a computer program product 330 comprising computer readable means 340. On this computer readable means 340, a computer program 320 can be stored, which computer program 320 can cause the processing circuitry no and thereto operatively coupled entities and devices, such as the communications interface 120 and the storage medium 130, to execute methods according to embodiments described herein. The computer program 320 and/or computer program product 330 may thus provide means for performing any actions of the scheduling device 14 as herein disclosed.

In the example of Fig. 8, the computer program product 330 is illustrated as an optical disc, such as a CD (compact disc) or a DVD (digital versatile disc) or a Blu-Ray disc. The computer program product 330 could also be embodied as a memory, such as a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM), or an electrically erasable programmable read-only memory (EEPROM) and more particularly as a non-volatile storage medium of a device in an external memory such as a USB (Universal Serial Bus) memory or a Flash memory, such as a compact Flash memory. Thus, while the computer program 320 is here schematically shown as a track on the depicted optical disk, the computer program 320 can be stored in any way which is suitable for the computer program product 330.

Fig. 9 is a flowchart of a method 60 according to embodiments. The user device 16 may, e.g., be any type of wireless communication device. Particular examples of such wireless communication device are mobile phones, smart phones, Internet of Things (loT) devices, etc., communicating wirelessly using an access point, base station 12, e.g., gNodeB (or gNB) or a base station supporting future 6G.

A method 60 is thus provided for reducing feedback signalling in a wireless communications system. The method 60 is performed in the user device 16 and comprises receiving 61, from the scheduling device 14, control information comprising a dynamic bundling configuration for uplink feedback, and transmitting 62, uplink feedback according to the received dynamic bundling configuration. In various embodiments, the transmitting 62 comprises transmitting the uplink feedback using dynamic bundling according to the received control information. The dynamic bundling may comprise any one or more of: an order in which at least a first and a second dimensions of the feedback bundling is to be applied, a dynamic indication of bundling granularity for one or more of the at least first and second dimensions, an indicated bundling granularity for one or more of the at least first and second dimensions,

In various embodiments, the receiving 61 comprises receiving the control information by a single Downlink Control Information, DCI, or by multiple DCIs. The one or more DCIs may thus schedule the bundled feedback bits or multiple data units in one or more transmissions.

In various embodiments the receiving 61 of control signalling comprises receiving data units at different times, or at different carriers, or at different spatial layers or at different transmission points scheduled by individual DCIs.

The method 60 in the user device 16 may comprise a step corresponding to any of the steps as described in relation to the method 50 in the scheduling device 14.

Fig. 10 is a schematic diagram showing functional units of a user device according to an embodiment. Processing circuitry 410 is provided using any combination of one or more of a suitable central processing unit (CPU), multiprocessor, microcontroller, digital signal processor (DSP), etc., capable of executing software instructions stored in a computer program product 630 (as in Fig. 12), e.g., in the form of a storage medium 430. The processing circuitry 410 may further be provided as at least one application specific integrated circuit (ASIC), or field programmable gate array (FPGA).

Particularly, the processing circuitry 410 is configured to cause the user device 16 to perform a set of operations, or actions, as disclosed herein. For example, the storage medium 430 may store the set of operations, and the processing circuitry 410 maybe configured to retrieve the set of operations from the storage medium 430 to cause the user device 16 to perform the set of operations. The set of operations may be provided as a set of executable instructions. The processing circuitry 410 is thereby arranged to execute methods as herein disclosed. The storage medium 430 may also comprise persistent storage, which, for example, can be any single one or combination of magnetic memory, optical memory, solid state memory or even remotely mounted memory.

The user device 16 may further comprise a communications interface 420 for communications with other entities, functions, nodes, and devices, over suitable interfaces. As such the communications interface 420 may comprise one or more transmitters and receivers, comprising analogue and digital components.

The processing circuitry 410 controls the general operation of the user device 16 e.g., by sending data and control signals to the communications interface 420 and the storage medium 430, by receiving data and reports from the communications interface 420, and by retrieving data and instructions from the storage medium 430. Other components, as well as the related functionality, of the user device 16 are omitted in order not to obscure the concepts presented herein.

Fig. 11 is a schematic diagram showing functional modules of a user device according to an embodiment. The user device 16 of Fig. 11 comprises a number of functional modules; a receive module 510 configured to receive, from the scheduling device 14, control information comprising a dynamic bundling configuration for uplink feedback, and a transmit module 520 configured to transmit uplink feedback according to the received dynamic bundling configuration. In general terms, each functional module 510, 520 maybe implemented in hardware or in software. Preferably, one or more or all functional modules 510, 520 maybe implemented by the processing circuitry 410, possibly in cooperation with the communications interface 420 and the storage medium 430. The processing circuitry 410 may thus be arranged to from the storage medium 430 fetch instructions as provided by a functional module 510, 520 and to execute these instructions, thereby performing any actions of the user device 16 as disclosed herein.

Fig. 12 shows one example of a computer program product comprising computer readable means according to an embodiment. On this computer readable means 640, a computer program 620 can be stored, which computer program 620 can cause the processing circuitry 410 and thereto operatively coupled entities and devices, such as the communications interface 420 and the storage medium 430, to execute methods according to embodiments described herein. The computer program 620 and/or computer program product 630 may thus provide means for performing any actions of the user device 16 as herein disclosed.

In the example of Fig. 12, the computer program product 630 is illustrated as an optical disc, such as a CD (compact disc) or a DVD (digital versatile disc) or a Blu-Ray disc. The computer program product 630 could also be embodied as a memory, such as a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM), or an electrically erasable programmable read-only memory (EEPROM) and more particularly as a non-volatile storage medium of a device in an external memory such as a USB (Universal Serial Bus) memory or a Flash memory, such as a compact Flash memory. Thus, while the computer program 620 is here schematically shown as a track on the depicted optical disk, the computer program 620 can be stored in any way which is suitable for the computer program product 630.

The inventive concept has mainly been described above with reference to a few embodiments. However, as is readily appreciated by a person skilled in the art, other embodiments than the ones disclosed above are equally possible within the scope of the inventive concept, as defined by the appended patent claims.

Claims

1. A method (50) for reducing feedback signalling in a wireless communications system, the method (50) being performed in a scheduling device (14) and comprising:

- dynamically selecting (52) at least a first and a second dimension for use in scheduling of feedback bits, the at least first and second dimensions selected at least among: time dimension, frequency dimension and spatial dimension, and

- dynamically controlling (54) bundling of the feedback bits from one or more data units according to the selected at least first and second dimensions.

2. The method (50) as claimed in claim 1, wherein the dynamic controlling (54) comprises dynamically controlling an order in which the at least first and second dimensions of the feedback bundling is applied.

3. The method (50) as claimed in claim 1, wherein the dynamic controlling (54) comprises dynamically indicating bundling granularity for one or more of the at least first and second dimensions.

4. The method (50) as claimed in any of the preceding claims, comprising scheduling, by a single Downlink Control Information, DCI, the bundled feedback bits or data units.

5. The method (50) as claimed in any of claims 1 - 3, comprising scheduling, by multiple DCIs, bundled feedback bits or multiple data units in different transmissions.

6. The method (50) as claimed in claim 5, wherein the transmissions occur at different times, or at different carriers, or at different spatial layers or at different transmission points.

7. The method (50) as claimed in any of the preceding claims, wherein the dynamic controlling (54) comprises configuring a set of bundling configurations semi- statically with Radio Resource Control, RRC, and dynamically selecting the bundling configurations using DCI signalling.

8. The method (50) as claimed in any of the preceding claims, wherein the data unit is one of: a code block, a code block group, a transport block and a code block bundle.

9. The method (50) as claimed in any of the preceding claims, wherein the feedback comprises at least one of: Hybrid Automatic Repeat Request acknowledgment (HARQ - ACK) and Hybrid Automatic Repeat Request negative acknowledgment (HARQ - NACK).

10. The method as claimed in any of the preceding claims, wherein the wireless communications system is one of: a Long Term Evolution (LTE) system, 5G New Radio or 6G.

11. The method (50) as claimed in any of the preceding claims, wherein the device (10) is a scheduling device in an access point, a base station or a gNB.

12. A computer program (320) for reducing feedback signalling in a wireless communications system, the computer program comprising computer code which, when run on processing circuitry (no) of a scheduling device (14), causes the scheduling device (14) to:

- dynamically select at least a first and a second dimension for use in scheduling of feedback bits, the at least first and second dimensions selected at least among: time dimension, frequency dimension and spatial dimension, and

- dynamically control bundling of the feedback bits from one or more data units according to the selected at least first and second dimensions.

13. A computer program product (330) comprising a computer program (320) according to claim 12, and a computer readable storage medium (340) on which the computer program (320) is stored.

14. A scheduling device (14) for reducing feedback signalling in a wireless communications system, the device (14) being configured to:

15. The scheduling device (14) as claimed in claim 14, wherein the scheduling device (14) is configured to dynamically control an order in which the at least first and second dimensions of the feedback bundling is applied.

16. The scheduling device (14) as claimed in claim 14, wherein the scheduling device is configured to dynamically indicate bundling granularity for one or more of the at least first and second dimensions. - The scheduling device (14) as claimed in any of the claims 14 - 16, configured to schedule, by a single Downlink Control Information, DCI, the bundled feedback bits or data units in a single transmission. . The scheduling device (14) as claimed in any of claims 14 - 16, configured to schedule, by multiple DCIs, bundled feedback bits or data units in different transmissions. . The scheduling device (14) as claimed in claim 18, wherein the transmissions occur at different times, or at different carriers, or at different spatial layers or at different transmission points. .The scheduling device (14) as claimed in any of claims 14 - 19, configured to dynamically control by configuring a set of bundling configurations semi-statically with Radio Resource Control, RRC, and to dynamically select the bundling configurations using DCI signalling. . The scheduling device (14) as claimed in any of claims 14 - 20, wherein the data unit is one of: a code block, a code block group, a transport block and a code block bundle. . The scheduling device (14) as claimed in any of claims 14 - 21, wherein the feedback comprises at least one of: Hybrid Automatic Repeat Request acknowledgment (HARQ - ACK) and Hybrid Automatic Repeat Request negative acknowledgment (HARQ - NACK). . The scheduling device (14) as claimed in any of claims 14 - 22, wherein the wireless communications system is one of: a Long-Term Evolution (LTE) system, 5G New Radio or 6G. . The scheduling device (14) as claimed in any of claims 14 - 23, wherein the scheduling device (14) is a scheduling device in a base station, a gNB or an access point. . A method (60) in a user device (16) for reducing feedback signalling in a wireless communications system, the method (60) comprising:

- receiving (61), from the scheduling device (14), control information comprising a dynamic bundling configuration for uplink feedback, and

- transmitting (62), uplink feedback according to the received dynamic bundling configuration. . The method (60) as claimed in claim 25, wherein transmitting (62) comprises transmitting the uplink feedback using a dynamic bundling configuration according to the received control information, wherein the dynamic bundling configuration comprises one or more of: an order in which at least a first and a second dimensions of the feedback bundling is to be applied, a dynamic indication of bundling granularity for one or more of the at least first and second dimensions, an indicated bundling granularity for one or more of the at least first and second dimensions, The method (60) as claimed in claim 25 or 26, wherein the receiving (61) comprises receiving the control information by a single Downlink Control Information, DCI, or by multiple DCIs. A user device (16) for reducing feedback signalling in a wireless communications system, the user device (16) being configured to:

- receive, from a scheduling device (14), control information comprising a dynamic bundling configuration for uplink feedback, and

- transmitting (62), uplink feedback according to the received dynamic bundling configuration. The user device (16) as claimed in claim 28, configured to transmit the uplink feedback using a dynamic bundling configuration according to the received control information, wherein the dynamic bundling comprises one or more of: an order in which at least a first and a second dimensions of the feedback bundling is to be applied, a dynamic indication of bundling granularity for one or more of the at least first and second dimensions, an indicated bundling granularity for one or more of the at least first and second dimensions, The user device (16) as claimed in claim 28 or 29, configured to receive by receiving the control information by a single Downlink Control Information, DCI, or by multiple DCIs. A computer program (620) for reducing feedback signalling in a wireless communications system, the computer program comprising computer code which, when run on processing circuitry (410) of a user device (16), causes the user device (16) to:

- transmit, uplink feedback according to the received dynamic bundling configuration. A computer program product (630) comprising a computer program (620) according to claim 31, and a computer readable storage medium (640) on which the computer program (620) is stored.