WO2022243106A1

WO2022243106A1 - Methods, terminals, base stations, systems and circuitry

Info

Publication number: WO2022243106A1
Application number: PCT/EP2022/062592
Authority: WO
Inventors: Martin Warwick Beale; Shin Horng Wong; Yassin Aden Awad
Original assignee: Sony Group Corporation; Sony Europe B.V.
Priority date: 2021-05-17
Filing date: 2022-05-10
Publication date: 2022-11-24

Abstract

A method of managing channel quality information in a mobile telecommunications network, the network comprising a terminal and a base station configured to provide a wireless interface to the terminal. The method comprises the terminal making channel quality measurements for the wireless interface; the terminal determining that the distribution of the channel quality measurements comprises at least a low quality peak and a high quality peak, the low quality peak being associated with a lower quality of the wireless interface relative to the quality of the wireless interface associated with the high quality peak; the terminal determining to report on at least a first peak, the first peak being one of the low quality peak and high quality peak; the terminal transmitting to the base station, a quality report comprising a first channel quality indication for a first subset of the channel quality measurements, the first subset of the channel quality measurements being associated with the first peak; and the base station taking a remedial measure in response to receiving the quality report and based on the channel quality indication in respect of the first subset of the channel quality measurements.

Description

Methods, Terminals, Base Stations, Systems and Circuitry

The present application claims the Paris Convention priority of European patent application EP21174215.0, filed 17 May 2021, the contents of which are hereby incorporated by reference.

Field

The present disclosure relates to methods, terminals, base stations, systems and circuitry for managing channel quality information in a wireless communications network.

Background

The "background" description provided herein is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it is described in this background section, as well as aspects of the description which may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present invention.

Third and fourth generation mobile telecommunication systems, such as those based on the 3GPP defined UMTS and Long Term Evolution (LTE) architecture, are able to support more sophisticated services than simple voice and messaging services offered by previous generations of mobile telecommunication systems. For example, with the improved radio interface and enhanced data rates provided by LTE systems, a user is able to enjoy high data rate applications such as mobile video streaming and mobile video conferencing that would previously only have been available via a fixed line data connection. The demand to deploy such networks is therefore strong and the coverage area of these networks, i.e. geographic locations where access to the networks is possible, may be expected to increase ever more rapidly.

Future wireless communications networks will be expected to support communications routinely and efficiently with a wider range of devices associated with a wider range of data traffic profiles and types than current systems are optimised to support. For example it is expected future wireless communications networks will be expected to efficiently support communications with devices including reduced complexity devices, machine type communication (MTC) devices, high resolution video displays, virtual reality headsets and so on. Some of these different types of devices may be deployed in very large numbers, for example low complexity devices for supporting the "The Internet of Things", and may typically be associated with the transmissions of relatively small amounts of data with relatively high latency tolerance.

In view of this there is expected to be a desire for future wireless communications networks, for example those which may be referred to as 5G or new radio (NR) system / new radio access technology (RAT) systems [1], as well as future iterations / releases of existing systems, to efficiently support connectivity for a wide range of devices associated with different applications and different characteristic data traffic profiles.

An example of such a new service is referred to as an Ultra Reliable Low Latency Communications (URLLC) service which, as its name suggests, requires that a data unit or packet be communicated with a high reliability and with a low communications delay. URLLC type services therefore represent a challenging example for both LTE type communications systems and 5G/NR communications systems. PCT application PCT/EP2017/071636, published as W02018050431 and entitled "Wireless telecommunications apparatus and methods" provides a discussion of low latency transmissions (e.g. URLLC transmissions) that may be of interest to the skilled reader.

The increasing use of different types of communications devices associated with different traffic profiles gives rise to new challenges for efficiently handling communications in wireless telecommunications systems that need to be addressed.

Summary

The present invention is defined in the independent appended claims. Further embodiments are provided in the dependent claims.

It is to be understood that both the foregoing general description and the following detailed description are illustrative only and are not restrictive, of the techniques and teachings of the present disclosure. While the present disclosure includes example arrangements falling within the scope of the claims, it may also include example arrangements that do not necessarily fall within the scope of the claims but which are then useful to understand the teachings and techniques provided herein.

Brief description of the drawings

A more complete appreciation of the disclosure and many of the attendant advantages thereof will be readily obtained as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein like reference numerals designate identical or corresponding parts throughout the several views, and:

Figure 1 schematically represents some aspects of an LTE-type wireless telecommunication system which may be configured to operate in accordance with certain embodiments of the present disclosure;

Figure 2 schematically represents some aspects of a new radio access technology (RAT) wireless telecommunications system which may be configured to operate in accordance with certain embodiments of the present disclosure;

Figure 3 is a schematic block diagram of an example infrastructure equipment and communications device which may be configured in accordance with example embodiments;

Figure 4 illustrates an example frame structure for an eMBB transmission;

Figure 5 illustrates an example frame structure for an URLLC transmission;

Figure 6 illustrates an example CQJ outer loop in a base station;

Figure 7 illustrates an example variation of a Correction Factor "CF" in a CQJ outer loop;

Figure 8 illustrates an example technique for determining a channel quality parameter;

Figure 9 illustrates another example of determining a channel quality parameter;

Figure 10 illustrates two examples of CQI distributions;

Figure 11 Illustrates variations in transmission configurations associated with the example distributions of Figure 10;

Figure 12 illustrates an example method in accordance with the present disclosure;

Figure 13 illustrates another example method in accordance with the present disclosure; Figure 14 illustrates a further example method in accordance with the present disclosure;

Figure 15 illustrates an example of reporting on a CQJ peak; and Figure 16 illustrates another example of reporting on a CQJ peak.

Detailed description of examples

Lone Term Evolution Advanced Radio Access Technology (4G)

Figure 1 provides a schematic diagram illustrating some basic functionality of a mobile telecommunications network / system 100 operating generally in accordance with LTE principles, but which may also support other radio access technologies, and which may be adapted to implement embodiments of the disclosure as described herein. Various elements of Figure 1 and certain aspects of their respective modes of operation are well-known and defined in the relevant standards administered by the 3GPP (RTM) body, and also described in many books on the subject, for example, Plolma H. and Toskala A [2], It will be appreciated that operational aspects of the telecommunications networks discussed herein which are not specifically described (for example in relation to specific communication protocols and physical channels for communicating between different elements) may be implemented in accordance with any known techniques, for example according to the relevant standards and known proposed modifications and additions to the relevant standards.

The network 100 includes a plurality of base stations 101 connected to a core network part 102. Each base station provides a coverage area 103 (e.g. a cell) within which data can be communicated to and from communications devices 104. Data is transmitted from the base stations 101 to the communications devices 104 within their respective coverage areas 103 via a radio downlink. Data is transmitted from the communications devices 104 to the base stations 101 via a radio uplink. The core network part 102 routes data to and from the communications devices 104 via the respective base stations 101 and provides functions such as authentication, mobility management, charging and so on. Communications devices may also be referred to as mobile stations, mobile terminals (MT), user equipment (UE), user terminals, mobile radios, terminal devices, and so forth. Base stations, which are an example of network infrastructure equipment / network access nodes, may also be referred to as transceiver stations / nodeBs / e-nodeBs, g-nodeBs (gNB) and so forth. In this regard different terminology is often associated with different generations of wireless telecommunications systems for elements providing broadly comparable functionality. Flowever, example embodiments of the disclosure may be equally implemented in different generations of wireless telecommunications systems such as 5G or new radio as explained below, and for simplicity certain terminology may be used regardless of the underlying network architecture. That is to say, the use of a specific term in relation to certain example implementations is not intended to indicate these implementations are limited to a certain generation of network that may be most associated with that particular terminology.

New Radio Access Technology (5G)

Figure 2 is a schematic diagram illustrating a network architecture for a new RAT wireless communications network / system 200 based on previously proposed approaches which may also be adapted to provide functionality in accordance with embodiments of the disclosure described herein. The new RAT network 200 represented in Figure 2 comprises a first communication cell 201 and a second communication cell 202. Each communication cell 201, 202, comprises a controlling node (centralised unit) 221, 222 in communication with a core network component 210 over a respective wired or wireless link 251, 252. The respective controlling nodes 221, 222 are also each in communication with a plurality of distributed units (radio access nodes / remote transmission and reception points (TRPs)) 211, 212 in their respective cells. Again, these communications may be over respective wired or wireless links. The distributed units 211, 212 are responsible for providing the radio access interface for communications devices connected to the network. Each distributed unit 211, 212 has a coverage area (radio access footprint) 241, 242 where the sum of the coverage areas of the distributed units under the control of a controlling node together define the coverage of the respective communication cells 201, 202. Each distributed unit 211, 212 includes transceiver circuitry for transmission and reception of wireless signals and processor circuitry configured to control the respective distributed units 211, 212.

In terms of broad top-level functionality, the core network component 210 of the new RAT communications network represented in Figure 2 may be broadly considered to correspond with the core network 102 represented in Figure 1, and the respective controlling nodes 221, 222 and their associated distributed units / TRPs 211, 212 may be broadly considered to provide functionality corresponding to the base stations 101 of Figure 1. The term network infrastructure equipment / access node may be used to encompass these elements and more conventional base station type elements of wireless communications systems. Depending on the application at hand the responsibility for scheduling transmissions which are scheduled on the radio interface between the respective distributed units and the communications devices may lie with the controlling node / centralised unit and / or the distributed units / TRPs.

A communications device or mobile terminal or UE 260 is represented in Figure 2 within the coverage area of the first communication cell 201. This communications device 260 may thus exchange signalling with the first controlling node 221 in the first communication cell via one of the distributed units 211 associated with the first communication cell 201. In some cases communications for a given communications device are routed through only one of the distributed units, but it will be appreciated that in some other implementations communications associated with a given communications device may be routed through more than one distributed unit, for example in a soft handover scenario and other scenarios.

In the example of Figure 2, two communication cells 201, 202 and one communications device 260 are shown for simplicity, but it will of course be appreciated that in practice the system may comprise a larger number of communication cells (each supported by a respective controlling node and plurality of distributed units) serving a larger number of communications devices.

It will further be appreciated that Figure 2 represents merely one example of a proposed architecture for a new RAT communications system in which approaches in accordance with the principles described herein may be adopted, and the functionality disclosed herein may also be applied in respect of wireless communications systems having different architectures.

Thus example embodiments of the disclosure as discussed herein may be implemented in wireless telecommunication systems / networks according to various different architectures, such as the example architectures shown in Figures 1 and 2. It will thus be appreciated that the specific wireless communications architecture in any given implementation is not of primary significance to the principles described herein. In this regard, example embodiments of the disclosure may be described generally in the context of communications between network infrastructure equipment / access nodes and a communications device, wherein the specific nature of the network infrastructure equipment / access node and the communications device will depend on the network infrastructure for the implementation at hand. For example, in some scenarios the network infrastructure equipment / access node may comprise a base station, such as an LTE-type base station 101 as shown in Figure 1 which is adapted to provide functionality in accordance with the principles described herein, and in other examples the network infrastructure equipment / access node may comprise a control unit / controlling node 221, 222 and / or a TRP 211, 212 of the kind shown in Figure 2 which is adapted to provide functionality in accordance with the principles described herein.

A more detailed illustration of a UE/communications device 270 (which may correspond to a communications device such as the communications device 260 of Figure 2 or the communications device 104 of Figure 1) and an example network infrastructure equipment 272, which may be thought of as a gNB 101 or a combination of a controlling node 221 and TRP 211, is presented in Figure 3. As shown in Figure 3, the UE 270 is shown to transmit uplink data to the infrastructure equipment 272 via uplink resources of a wireless access interface as illustrated generally by an arrow 274 from the UE 270 to the infrastructure equipment 272. The UE 270 may similarly be configured to receive downlink data transmitted by the infrastructure equipment 272 via downlink resources as indicated by an arrow 288 from the infrastructure equipment 272 to the UE 270. As with Figures 1 and 2, the infrastructure equipment 272 is connected to a core network 276 via an interface 278 to a controller 280 of the infrastructure equipment 272. The infrastructure equipment 272 includes a receiver 282 connected to an antenna 284 and a transmitter 286 connected to the antenna 284. Correspondingly, the UE 270 includes a controller 290 connected to a receiver 292 which receives signals from an antenna 294 and a transmitter 296 also connected to the antenna 294.

The controller 280 is configured to control the infrastructure equipment 272 and may comprise processor circuitry which may in turn comprise various sub-units / sub-circuits for providing functionality as explained further herein. These sub-units may be implemented as discrete hardware elements or as appropriately configured functions of the processor circuitry. Thus the controller 280 may comprise circuitry which is suitably configured / programmed to provide the desired functionality using conventional programming / configuration techniques for equipment in wireless telecommunications systems. The transmitter 286 and the receiver 282 may comprise signal processing and radio frequency filters, amplifiers and circuitry in accordance with conventional arrangements. The transmitter 286, the receiver 282 and the controller 280 are schematically shown in Figure 3 as separate elements for ease of representation. However, it will be appreciated that the functionality of these elements can be provided in various different ways, for example using one or more suitably programmed programmable computer(s), or one or more suitably configured application-specific integrated circuit(s) / circuitry / chip(s) / chipset(s). As will be appreciated the infrastructure equipment 272 will in general comprise various other elements associated with its operating functionality.

Correspondingly, the controller 290 of the UE 270 is configured to control the transmitter 296 and the receiver 292 and may comprise processor circuitry which may in turn comprise various sub-units / sub circuits for providing functionality as explained further herein. These sub-units may be implemented as discrete hardware elements or as appropriately configured functions of the processor circuitry. Thus the controller 290 may comprise circuitry which is suitably configured / programmed to provide the desired functionality using conventional programming / configuration techniques for equipment in wireless telecommunications systems. Likewise, the transmitter 296 and the receiver 292 may comprise signal processing and radio frequency filters, amplifiers and circuitry in accordance with conventional arrangements. The transmitter 296, receiver 292 and controller 290 are schematically shown in Figure 3 as separate elements for ease of representation. However, it will be appreciated that the functionality of these elements can be provided in various different ways, for example using one or more suitably programmed programmable computer(s), or one or more suitably configured application-specific integrated circuit(s) / circuitry / chip(s) / chipset(s). As will be appreciated the communications device 270 will in general comprise various other elements associated with its operating functionality, for example a power source, user interface, and so forth, but these are not shown in Figure 3 in the interests of simplicity.

The controllers 280, 290 may be configured to carry out instructions which are stored on a computer readable medium, such as a non-volatile memory. The processing steps described herein may be carried out by, for example, a microprocessor in conjunction with a random access memory, operating according to instructions stored on a computer readable medium.

5G, URLLC and Industrial Internet of Things and channel quality

Systems incorporating NR technology are expected to support different services (or types of services), which may be characterised by different requirements for latency, data rate and/or reliability. For example, two particular types of services have been defined as desired NR functionalities:

Enhanced Mobile Broadband (eMBB)

Ultra Reliable & Low Latency Communications (URLLC)

Enhanced Mobile Broadband (eMBB) services are characterised by high capacity with a requirement to support up to 20 Gb/s. For efficient transmission of large amounts of data at high throughput, eMBB is likely to use slot-based transmissions to minimise the overhead used. An example eMBB frame structure in the downlink is shown in Figure 4 with transmission period T_QMBB, where the control channel at the beginning of the slot uses fewer transmission resources than the data channel.

An important requirement for URLLC is low latency measured from the ingress of a layer 2 packet to its egress from the network, with a proposed target of 1 ms. The URLLC data is expected to be short and hence short scheduling times are desirable, where the control and data transmissions have a short duration. As a result, the URLLC transmissions use a frame duration that is less than that of the eMBB frame. For example, while a typical eMBB frame duration is 1ms, a URLLC frame structure can use a much shorter transmission period (for example 0.25 ms). Figure 5 illustrates an example frame structure for a URLLC transmission. As a result, the control and data channels occupy a smaller time period (i.e. the transmission period of URLLC

is smaller than that of eMBB

While the relative overhead is expected to be greater with URLLC transmissions, the URLLC transmissions are also associated with shorter latency performance (i.e. a better performance with less latency), compared to eMBB transmissions.

The desired targets for URLLC services also include a reliability of 1 - 10⁵ (99.999 %) or higher for one transmission of a 32 byte packet with a user plane latency of 1 ms [3], In some scenarios, there may be a requirement for a reliability of 1 - 10⁶ (99.9999 %) or higher with either 0.5ms or 1ms of user plane latency.

Massive Machine Type Communications (mMTC) is another example of a service which may be supported by NR-based communications networks.

In addition, systems may be expected to support further enhancements related to Industrial Internet of Things (MoT) in order to support services with new requirements of high availability, high reliability, low latency, and in some cases, high-accuracy positioning.

In many communication systems (e.g. FISPA, LTE, NR), the UE sends channel quality information to the base station (e.g. BTS, NodeB, eNB, gNB, etc.) allowing the base station to track fast fading, channel quality, etc. and to apply a suitable modulation and coding scheme in the downlink. It is noteworthy that, in the present disclosure, "gNB" will be used interchangeably with base station. The CQI can be signalled from the UE to the base station as an indication of a preferred modulation and coding scheme (MCS). The signalled preferred MCS typically relates to the MCS that would result in a target block error rate (BLER) if that MCS were applied by the base station. The CQJ is generally determined by the UE based on the Signal-to-Noise Ratio (SNR) or Signal-to-Noise plus Interference Ratio (SINR) observed at the UE. The UE would typically implement a look up table mapping measured SNR or SINR to reported CQI.

In legacy systems, the CQI specification or selection relates to the MCS that would be required to achieve a 10% BLER. If a lower BLER target is used, the base station will derive from the CQI an MCS which is expected to achieve the lower BLER target. For example, the base station may wish to operate at a BLER target of 0.1% or lower for URLLC use cases.

Based on the above discussion, it is apparent that there are many cases where the base station cannot necessarily rely too heavily on a CQI report from the UE in order to choose an MCS for downlink transmissions when the CQI report comprises limited information, for example a single CQI value associated with the MCS selected to achieve a 10% BLER target. Example sub-optimal situations include an imperfect UE implementation (which leads to CQI reporting which may not correspond to what the base station would normally expect from a terminal in this situation) or a BLER target for the base station that is different to BLER target assumed at the UE.

In order to try to cater for the above imperfections, the base station would typically implement a "CQI outer loop". The CQI outer loop is a control loop or feedback loop that controls the MCS applied to downlink transmissions based on the reported CQI and on the ACK / NACK feedback (or hybrid automatic repeat request system "HARQ" feedback) from the UE.

An example of a CQI outer loop, as implemented in a base station and a UE, is shown in Figure 6. The actual implementation of CQI outer loop functionality is not currently specified in standard documents. In other words, this function is implementation dependent and may vary from one base station to another. Flence Figure 6 is just one possible implementation of a CQI outer loop, if provided.

The functionalities of elements within the CQI outer loop of Figure 6 are described below:

- Convert to SNR (or SINR): the base station receives a CQI report from the UE (which can be considered to be an indication of an MCS expected by the UE to be required to achieve a 10% BLER). The base station can convert that CQI report into a corresponding SNR. The conversion could be implemented through the use of a look up table (of CQI value vs SNR).

It is noteworthy that the UE can send periodic and/or aperiodic CQI reports, depending on configuration from the base station.

- Correction (illustrated as a circle with a cross inside in Figure 6): the SNR value is corrected by a correction factor, CF, to produce a corrected SNR. An example correction function would produce a corrected SNR as:

SNRcorrected — SNRj_n X CF

- Choose MCS: an MCS for a PDSCH transmission is chosen, based on SNR_COrreaed· The choice of MCS based on SNR could be made, for example, by use of a look up table.

Transmit PDSCFi: the PDSCH is transmitted by the base station using the MCS determined in the previous step. - PDSCH reception feedback: the UE receives the PDSCH and sends an ACKor NACK to the base station, for example via the PUCCH. An ACK will indicate a successful transmission (of the PDSCH) while a NACK will indicate an unsuccessful transmission.

- Update correction factor: the base station updates the correction factor, based on ACK or NACK status for previous downlink transmissions. For example: o NACK received: if the PDSCH had been NACKed, it would indicate that the MCS chosen had been too optimistic. SNR_¥rrected should have been lower, leading to a lower applied MCS. Hence the correction factor can be reduced. o ACK received: if the PDSCH had been ACKed, it would indicate that the MCS chosen had been too pessimistic. SNR_COrrected should have been higher, leading to a higher applied MCS. Hence the correction factor can be increased.

From one perspective, the CQI outer loop can be seen as attempting to control the correction factor (and hence the applied MCS) with a view to operating at the expected BLER taking into account the varying SNR conditions.

One method of varying the correction factor, CF, includes using a step size parameter, CF_ste_P, and applying the following updates to the correction factor, based on the ACK / NACK status reported by the UE and on a parameter n:

In a steady and stable environment, these updates are expected to lead to BLER = 1/n being achieved.

Figure 7 illustrates an example variation with time of a Correction Factor "CF" in a CQJ outer loop using the example algorithm described above. This illustrative example is for a BLER target of 10% (such that n = 10 in the algorithm above).

Figures 6 and 7 are illustrative example which aim to illustrate how some of the legacy systems use channel quality reporting for determining modulation and coding configurations to achieve a target error rate.

As discussed above, in legacy systems, the reported CQJ relates to the MCS that would be required to achieve a 10% BLER, based on the UE's estimations. If a lower BLER target is used, the base station will derive from the CQI an MCS which is expected to achieve the lower BLER target. How the base station can derive a modulation and coding scheme for different BLER targets can present further difficulty, as will be appreciated based on Figures 8 and 9 and their discussion below.

More generally, many of these difficulties derive from the fact that the CQI was originally designed to accommodate a single target BLER. In other words, while the CQI was originally a one-dimensional parameter (derived from radio conditions only, with a fixed BLER target), changes to telecommunications systems result in the CQI metric being used effectively as at least a two-dimensional parameter (which depends on both radio conditions and a target transmission reliability measure). Modifying these mechanisms to try to improve their operations, while maintaining the current or legacy arrangements and techniques at the same time, can be challenging. Figure 8 illustrates an example technique for determining a channel quality parameter. In this example, the channel quality parameter is derived for a first communication target and based on a channel quality parameter for a second communication target.

This figure shows a graph of BLER (an example of a transmission reliability measure) against CQJ (an example of a channel quality measure). A higher CQI ( CQ MBB ) is appropriate for a higher BLER target (such as BLER = 10%) as the modulation and coding scheme will be selected to be less robust if more errors can be accommodated. On the other hand, if the BLER target is lower (e.g. BLER = 10⁵), e.g. when errors are less tolerated, then a lower CQI (e.g.

would be appropriate in order to have more robust transmissions. As discussed above, a CQI is usually associated with an MCS such that a lower CQI would result in a "lower" MCS (namely, an MCS with a lower throughput and higher robustness). Accordingly, once the gNB has received the

from the terminal, it will attempt to derive from it the for a lower BLER target. The difference between the two CQI values can be seen as an offset CQ/₀//_set that the gNB uses to determine a CQI that would be applicable for the lower BLER.

As will be appreciated, by how much the gNB needs to offset or backoff the CQI for a higher BLER target will depend not only on the other BLER target but also on the radio conditions and on the reliability of the CQI measurements. For example, in cases where the CQI measurements are less reliable, the gNB would preferably apply a more conservative estimation of the low BLER CQI than in cases where the CQI is (relatively) more reliable. A higher variation in channel quality measurements (e.g. CQI, interference, SINR, etc.) can be associated with different radio conditions or situations such as some channels exhibiting deeper fades than other channels, different amounts of interference (from other UEs, base stations or from non-telecommunications equipment), etc.

A typical guiding principle is that systems will often aim to optimise spectral efficiency. For example, the system will try to use a modulation and coding scheme which enables the best throughput while still meeting the BLER target. For example, using a modulation and coding scheme which is selected too conservatively will result in a lower spectral efficiency than can otherwise be achieved while meeting the BLER target. On the other hand, selecting a modulation and coding scheme not cautiously enough can degrade the BLER performance such that the BLER target may not be met, which would also be undesirable.

With this in mind, it has been suggested that a new "Channel State Information" CSI reporting scheme could be implemented, which might be applicable for Release 17 and/or IIOT-URLLC communications. The CSI reporting traditionally includes the CQI value as discussed above, such that it includes an indication of which MCS the terminal would recommend be applied to receive the downlink transmissions at the appropriate BLER. The CSI reporting can also report on other aspects, for example which beam forming parameters the terminal would recommend the gNB to use, the number of layers it would recommend the gNB to use, MIMO conditions etc., although these are secondary to the disclosure and techniques discussed herein. Some of the new reporting aspects considered relate to CQI and/or SINR and/or interference statistics.

It has been suggested that the terminal could report parameters such as minimum, maximum, mean, variance and x-percentile values (see reference [4]). Reporting the mean and variance values has been suggested in order to provide the gNB with a more complete view of the interference distribution and/or of the distribution of the channel quality measurements, from the UE's perspective. For example, a large variance would indicate that the interference (or more generally, radio conditions) can be more unpredictable resulting in a larger distribution of the interference or other quality measurements. On that basis, the gNB may select an appropriate MCS more conservatively. On the other hand, a lower variance would indicate that the interference or quality measurement distribution to be less spread and the reference (e.g. mean or average) interference or quality measurements to be more reliable. On that basis, the gNB may select an appropriate MCS less conservatively, expecting better radio conditions than with the same interference or quality reference (e.g. CQJ) value associated with a higher variance.

Different reporting values have been suggested, such as a mean, variance, fifth percentile, eighth percentile, etc. with a view to providing the gNB with a more complete view of the distribution of the CQJ (or other channel quality measurements).

Said differently and using the terminology mentioned in respect of Figure 8, with a greater variance more caution may be applied and the base station may derive the MCS for a low BLER target using a greater "backoff" or "offset" parameter relative to the MCS associated with the higher BLER target.

It will appreciated that in cases where a CQI is indicative of an MCS, these teachings are equally applicable to a determination by the gNB of the CQI values associated with the different BLER targets (with the MCS being derived from the determined CQI values), applying a greater or smaller offset depending on the conditions, and to a determination by the gNB of the MCS associated with different BLER targets, applying a greater or smaller offset on the robustness and throughput of the MCSs depending on the conditions.

This is illustrated with the example of Figure 9 which illustrates another perspective on determining a channel quality parameter. In this example, the channel quality parameter is derived for a first communication target and based on a channel quality parameter for a second communication target, while taking into account a variance associated with the channel quality parameter. As shown in Figure 9, when there is a higher or lower variance in the CQI, the CQI and/or MCS associated with the lower BLER target will vary. Otherwise, if there is a large variance associated with the reported CQI (e.g. larger than expected by the gNB), the gNB may apply an incorrect modulation and coding scheme (MCS) to the transmission, leading to increase in BLER. The figure shows that when there is a high CQI variance, a higher CQI backoff (CQI₀ffset_highmr) can be applied compared to the backoff or offset value (CQI offset jomar) associated with a lower CQI variance. Presented differently, in cases where the base station implements a determination which is based on a technique similar to that illustrated in Figures 8 and 9, the base station will apply a greater scaling factor to the CQI/BLER curve when the radio conditions are more variable compared to the scaling factor applied to the CQI/BLER curve when the radio conditions are more predictable and stable. It will be appreciated that these teachings apply equally to other radio quality measurements (e.g. SINR, interference, etc.) and to cases where the determination is not based on a curve as illustrated. In some cases, a table may be used and/or the graphical representation of the relation between the quality measurements and the MCS (or MCS-associated parameter, e.g. MCS) may comprise one or more steps.

Using the analogy mentioned above, as the MCS determination depends not only on the CQI but also on the BLER target and on the variance, this becomes a three dimensional determination. This can make optimal MCS determination much more complex. While the reporting of values such as mean and variance values have been proposed with a view to addressing this three dimensional problem, this approach also suffers from limitations.

In particular, it has been identified that, in many cases, reporting of a single mean and variance value may not provide an accurate enough view of CQI, SINR and/or interference distribution to the base station. This is because the reporting of a pair of mean and variance values assumes a Gaussian distribution of values, or at least only enables the base station to derive a Gaussian (or similar) distribution of the quality measurement values. While a Gaussian distribution may be expected in a number of cases, there are also a number of other cases where the distribution of the measurements will not follow a Gaussian bell curve (or equivalent modelling technique). In these cases, the base station may not be able to obtain a meaningful representation of the channel quality measurements values as obtained by the terminal and, accordingly, may select an MCS which is not adapted to the terminal's radio conditions.

On the other hand, asking the terminal to report on the complete distribution of all measurements would significantly increase the signalling overhead and can therefore also be undesirable.

Figure 10 illustrates two examples of CQI distributions (the y-axis can for example be based on a number of occurrences of the CQI values or on a probability associated with the CQI value). It has been appreciated that in many cases, the channel quality measurements may not follow a Gaussian (see the first dashed-line distribution of Figure 10) or bell curve but may instead include at least a secondary peak (see the second solid line distribution of Figure 10). For example, in a case where a neighbouring base station or other radio equipment creates interference for the terminal, the quality measurements will drop when interference affects the terminal but may return to a "normal" quality measurement level when the interference stops. Presented differently, the interference from a neighbouring base station (or other transmitting device) can create a cluster of lower CQJ values around a lower CQI value. Accordingly, the distribution of the channel or radio quality measurements may comprise two or more peaks.

If there are two separate and somewhat distant peaks of measured quality on the channel (e.g. interference or CQI), each with a small variance, as illustrated in the second graph of Figure 10, producing a single pair (of a reference measurement value and an associated variance) would result in a large variance being reported. This is because in the bottom (solid) graph, values on the left-hand peak of the distribution contribute disproportionately to the calculation of the variance and the variance estimation will be inflated as a result.

It will be appreciated that, in the field of statistics, the term "variance" is used in a general sense to mean a measurement of the spread of a peak in a portion of the (e.g. CQI) distribution. Alternatively, the term "variance" can be interpreted as meaning the variance of a probability distribution of (e.g. CQI) samples that occur within a range of values surrounding a peak of the distribution.

This is likely to be interpreted as the terminal experiencing interference that is highly random, even though this is not the case and the interference (or other radio conditions) show measurements concentrated around two separate values. On one hand, the terminal would then make radio quality measurements, which would result in a distribution as shown in the second (solid) graph of Figure 10. On the other hand, if the terminal is configured to report a (single) reference value and associated variance, the base station might reconstruct the measurements of the terminal as being approximately as illustrated in the first (dashed) graph of Figure 10. As can be seen, the top distribution is Gaussian or bell curved and has a relatively large bell-shaped curve. The lower distribution has two concentrated peaks, where the left-hand peak (associated with poorer CQI values) may be due to interference (for example, transmissions in a neighbour cell may cause these low CQI values) and the right-hand peak may correspond to the channel or radio quality experience without the interference (for example, when the neighbour cell is not transmitting, not on the measured frequencies or not near the terminal). In other words, the base station would have an inaccurate representation of the channel quality measured by the terminal. Figure 11 Illustrates the variations in transmission configurations associated with the two examples of CQJ distributions of Figure 10. As illustrated in Figure 11, if the base station assumes that the top distribution is an accurate representation of the CQJ distribution seen by the terminal, when the base station is determining an MCS for a lower BLER target than the default one corresponding to the peak, it is likely to identify a higher CQI value than if it had been aware of the actual distribution. From one perspective, while the variance of the two distributions may be the same, the lower distribution is more problematic for low BLER (e.g. URLLC) transmissions since there are more times when there are lower CQI values in this distribution.

As illustrated in Figure 11, the maximum CQI value that is expected to lead to a BLER of 10⁵ is lower for the two-peak bottom (solid line) distribution than it is for the Gaussian top (dashed line) distribution. In other words, the gNB would need to select a lower CQI for low BLER transmissions (which is equivalent to applying a larger CQI offset) for the two-peak distribution than for the Gaussian distribution.

As a result, the MCS may not be sufficient for the terminal to meet its BLER target when using the currently suggested signalling of the variance of the CQI distribution, especially in cases where the channel quality measurements (e.g. CQI, SINR, interference level, etc.) distribution is other than Gaussian. Additionally, attempts to reduce the likelihood of this type of problem happening by always assuming worse radio conditions than reported by the terminal, would result in a sub-optimal spectral efficiency in many instances, for example when the distribution is broadly similar to a Gaussian distribution. Furthermore and as mentioned above, transmitting detailed information about the distribution of the measurements would greatly increase the signalling overhead, which is also unattractive.

The present disclosure provides techniques for a system to receive helpful but efficient signalling regarding a distribution of channel quality measurements, with a view to providing more reliable and more spectrally efficient low BLER operations of the network.

Figure 12 illustrates an example method in accordance with the present disclosure. The method is helpful for managing channel quality information in a mobile telecommunications network, the network comprising a terminal and a base station configured to provide a wireless interface to the terminal.

The method comprises the terminal making channel quality measurements for the wireless interface. For example, making channel quality measurements may comprise measuring at least one of: signal-to-noise ratio "SNR", a signal-to-interference plus noise ratio "SINR", signal-to-noise plus distortion ratio "SNDR" and an interference level on at least one radio channel of the wireless interface.

The terminal then determines that the distribution of the channel quality measurements comprises at least a low quality peak and a high quality peak. The low quality peak is associated with a lower quality of the wireless interface relative to the quality of the wireless interface associated with the high quality peak. The low quality peak may for example reflect measurements made when an interference level was higher. It should be noted that in cases where interference is being measured the first peak on the x-axis will be expected to correspond to a relatively higher quality peak while a second peak further along the x-axis will be associated with a lower quality.

Accordingly, rather than assume that the distribution will be a Gaussian or close to a Gaussian distribution, the terminal can identify two (or more) peaks or modes in the distribution of the measurements.

The terminal can then determine to report on a first peak (at least) where the first peak is one of the low quality peak and high quality peak. In some cases, the terminal will report only on the low quality peak. In other cases, the terminal will report only on the high quality peak. In yet other cases, the terminal will report on both peaks (separately).

The terminal can then transmit to the base station, a quality report (e.g. first quality report) comprising a first channel quality indication for a first subset of the channel quality measurements, the first subset of the channel quality measurements being associated with the first peak. In cases where the terminal reports on at least another peak, the report may comprise a further channel quality indication associated with the other peak.

It will be appreciated that the channel quality indication can take various forms, including a statistical parameter or characteristic of a channel quality metric (e.g. CQI) distribution, such as a mean or variance; or a channel quality indicator (CQI), indicating as estimate of the MCS that the gNB would need to apply to achieve a target BLER (block error rate) at the terminal. The channel quality indication can be transmitted in different ways. For example, the channel quality indication can be transmitted in an RRC message or via a PUCCH or PUSCH. In some cases, a channel quality indication comprising one or more statistical parameters for a CQI distribution is transmitted in an RRC message and a channel quality indication comprising a channel quality indicator (CQI) is transmitted via a PUCCH or PUSCH.

The base station, once it has received the quality report, can take a remedial measure in response to the quality report and based on the channel quality indication for the first subset of the channel quality measurements.

In some cases, the first channel quality indication in the report is a channel quality indicator "CQI", an interference level measurement and/or a SINR measurement. It will be appreciated based on the discussions above that any indication which is associated with an expected modulation and coding scheme configuration can also be considered as a channel quality indicator.

In some examples, the first channel quality indication identifies a first main channel quality value and a first variance value. The first main channel quality value can be one of an average, mean, mode, median and peak value for the first subset of the channel quality measurements and the first variance value can be a variance value for the first subset of the channel quality measurements, e.g. relative to the first main channel quality value or to another value (e.g. another one of average, mean, mode, median and peak value for the first subset of the channel quality measurements).

In some cases, the terminal can determine a first contribution factor for the first subset of the channel quality measurements. The contribution factor provides an indication of the contribution of the first subset of the channel quality measurements to the channel quality measurements. For example, it may provide a measure of how many measurements are associated with the first peak as a percentage of the total number of measurements. When such a first contribution factor (or value) is determined, the first channel quality indication can include the first contribution factor such that the terminal can transmit information regarding the contribution of the peak (or of the measurements associated with the first peak) to the entire distribution.

The quality report may also comprise a second channel quality indication for a second subset of the channel quality measurements, the second subset of the channel quality measurements being associated with a second peak of the distribution of the channel quality measurements and being different from the first peak. Accordingly, the terminal may report on the first peak and on the second peak, as separate peaks or parts of the distribution. In some cases, the second channel quality indication can identify a second main channel quality value and a second variance value. The second main channel quality value may then be one of an average, mean, mode, median and peak value for the second subset of the channel quality measurements and the second variance value may then be a variance value for the second subset of the channel quality measurements, e.g. relative to the second main channel quality value or to another value (e.g. another one of average, mean, mode, median and peak value for the second subset of the channel quality measurements).

The method may also comprise the terminal determining that the distribution of the channel quality measurements comprises a plurality of peaks (e.g. comprising the low quality peak and the high quality peak), and transmitting to the base station, for each of the plurality of peaks, a respective channel quality indication for the respective subset of the channel quality measurements. In some cases, the respective channel quality indications may be transmitted in the same quality report or in separate quality reports. For example, the respective channel quality indications may be transmitted in the first quality report and at least one further quality report. In some examples, the terminal may alternate between reporting on two or more peaks between quality reports. For example, the terminal may report about a first peak at a first reporting opportunity and about a second peak at the next reporting opportunity.

As will be appreciated, in some examples the quality report will comprise channel quality indication(s) for some but not all of the channel quality measurements. For example, not all peaks may be reported on in a single quality report. From one perspective, the quality report then does not comprise a second channel quality indication for a second subset of the channel quality measurements, the second subset of the channel quality measurements being associated with a second peak of the distribution of the channel quality measurements. Accordingly, the quality report will comprise a channel quality indication for the first peak but not for the second peak.

In other cases, all peaks may be reported on in the same report. As will be appreciated in view of the discussion above, the terminal will identify two or more peaks and, if reporting on the peaks, it can potentially provide a separate and respective channel quality indication on each (reported) peak, rather than provide channel quality indications by generating a report for all the corresponding combined measurements. For example, if reporting on all peaks at the same time, the terminal can determine that the distribution of the channel quality measurements comprises a plurality of peaks, and transmit to the base station, for each of the plurality of peaks, a respective channel quality indication for the respective subset of the channel quality measurements, wherein the respective channel quality indications are transmitted in the (same) quality report.

The terminal determining to report on the first peak may also comprise one or more of the terminal: determining that the first peak is the lowest quality peak of the distribution of the channel quality measurements. For example, the terminal may be configured to always report on the lowest quality peak as it will be associated with the worst case scenario and may thus be helpful for determining an MCS for a low BLER target. determining that the first peak is the highest quality peak of the distribution of the channel quality measurements. For example, the terminal may be configured to always report on the highest quality peak as it can provide the base station with a clearer view of the channel quality without interference from a neighbouring base station for example. determining that all peaks of the distribution of the channel quality measurements will be included in the report. As mention above, this can enable the base station to have a more accurate reconstruction of the channel quality measured by the terminal. determining that the first subset of the channel quality measurements is associated with one of a predetermined maximum number of peaks of the distribution of the channel quality measurements. For example, the terminal may be configured to report on no more than one, two, three or more peaks and the first peak may be one of the one, two, three or more peaks. These peaks can be selected for example based on associated quality (e.g. only the three lowest quality peaks will be reported) or based on their contribution (e.g. only the two peaks with the largest contributions will be reported). selecting the first subset of the channel quality measurements based on a configuration to alternate reports between two or more of the peaks of the distribution of the channel quality measurements. For example, at the next reporting opportunity, the terminal may select measurements for another peak and may report on the first peak again in a subsequent reporting opportunity. disregarding one or more peaks of the distribution of the channel quality measurements associated with a contribution factor of less than a predetermined threshold. For example, the terminal may be configured to disregard peaks which have a contribution to the overall distribution such that they have a negligible impact. If the terminal is configured to ignore peaks associated with a contribution of 10⁶ or less, anomalies which are not expected to affect the quality reporting and/or MCS selection can be ignored or disregarded. In a case where the terminal is also configured to report on the lowest peak or peaks, this can help ensure that the terminal will only report on peaks that are expected to affect the MCS selection and the lowest peak in the distribution may not be reported if its contribution is too low. disregarding one or more peaks of the distribution of the channel quality measurements associated with a contribution factor of less than a predetermined fraction of a target block error rate for the terminal. The principles and teaching provided in the previous option apply equally to this example. This can have the benefit of adapting the filtering of peaks to report on based on the BLER target. For example, the terminal may report on a particular peak when the system operates with a first low BLER target of 10⁵ but may not report on the same particular peak with a second higher BLER target of 10³. This can happen if the terminal is configured to report on peaks having a contribution of at least 10% of the BLER target and where the peak's contribution is of 2x10 ^s. The peak contribution is of 20% of the first BLER target of 10⁵ such that it will be selected for reporting. However, with the second BLER target of 10³, the peak has a contribution of 0.2% such that it will not be selected for reporting to the base station. disregarding one or more peaks of the distribution of the channel quality measurements when the cumulative contribution factor of peaks of lower quality is above a predetermined threshold. For example, the terminal may report on the lowest quality peaks (optionally after having applied filtering as discussed above) until the cumulative contribution of the lowest quality peaks is above a predetermined threshold. For example, the terminal may be set with a threshold of 20% (or 0.2) and it will select peaks, starting from the lowest peak Peaki and including the next lowest peak until Peak_n, where the sum of the contributions for Peak_!... Peak_n is above the threshold (e.g. where the sum of the contributions for Peaki... Peak_n-i is below the threshold and above the threshold for Peaki... Peak„, e.g. if adding the contribution of Peak_n takes the sum of contributions above the threshold). On that basis, the base station may be made aware of the lowest quality peaks (in some cases filtered peaks having a significant enough contribution) which, together, provide a large enough contribution that the base station can have a better representation of the lowest quality peaks (which are often expected to be the most relevant ones for the base station) and can use the reporting data to make more informed decisions. disregarding one or more peaks of the distribution of the channel quality measurements when the cumulative contribution factor of peaks of lower quality of the distribution is above a predetermined fraction of a target block error rate for the terminal. The same teachings as discussed above apply here, but where the threshold is set in respect of a BLER target, for example at least 10% of a BLER target. selecting peaks of the distribution based on a predefined number of peaks and based on the selected peaks with the greatest contribution factors in the distribution. For example, the terminal may be configured to report on one, two or more peaks where the peaks are selected based on their relative contributions. The peaks with the highest contribution will be reported and the peaks having a smaller contribution may then be left aside as more minor contributors to the distribution. Similarly to what is discussed above, in some cases the peaks may be selected by selecting the peaks having the greatest contribution factors in the distribution and based on a cumulative contribution factor of the selected greatest contribution peaks being above a threshold (defined as an absolute value or as a relative value based on a BLER target for example).

In the present disclosure, when considering two or more peaks (and/or two or more sets of measurements associated with two or more peaks), the cumulative contribution factor of the two or more peaks corresponds to the sum of the contribution factors of each of the two or more peaks. For example a first peak with a contribution factor of 12% and a second peak with a contribution factor of 49% have a cumulative contribution factor of 61%.

In some implementations, the terminal transmitting the quality report may comprise the terminal selecting a set of resources for the first subset of resources for transmitting the quality report based on the position of the first peak in an ordered list of peaks of the distribution of the channel quality measurements ordered by level of quality associated with the quality measurements. For example, the terminal may use a first set of resources for reporting on a lowest quality peak and may use a different set of resources for reporting on another peak (e.g. the next lowest quality peak, a biggest contributor peak, etc.). In some cases, the peak position can help derive a timing of the resources to be used and/or the peak position can help derive one or more frequency resources to be used. Looking at the timing aspects, the terminal may for example report on a lowest peak at a particular timing opportunity (based on a predefined and/or signalled configuration), then report on a next lowest peak, etc. If M timing opportunities are offered to the UE, the UE may report up to M peaks to the base station, selected based on a pre-agreed mechanism.

In one example (example A), the terminal reports on peaks from a lowest quality peak to a highest quality peak, selecting up to M peaks. In another example (example B), the terminal may report on peaks from a highest contributor peak to a lowest contributor peak, selecting up to M peaks. In yet another example, the terminal may first report on a highest quality peak (expected to be the "main" peak in many cases) and then report again for the lowest quality peak and selecting peaks from lowest quality peak to the highest quality peak (excluded as it has been reported first), e.g. continuing according to example A above. In this manner, the base station is expected to be aware of the quality measurements for the main cluster of CQJ values but also to receive information about the other peaks in order of importance (from a quality perspective). In a further example, the terminal may first report on a highest quality peak (expected to be the "main" peak in many cases) and then report again from the highest contributor peak to the lowest contributor peak (excluding the highest quality peak as it has been reported first), e.g. continuing according to example B above. In this manner, the base station is expected to be aware of the quality measurements for the main cluster of CQI values but also to receive information about the other peaks in order of importance (from a contribution perspective).

In one example, the quality report comprises an identifier for the first peak or first subset of the channel quality measurements, and the method further comprises the terminal transmitting, at a later point in time and to the base station, a further quality report. The further quality report comprising the identifier and indicating that the first peak is active. Accordingly, when the characteristics of the peak(s) are for example expected not to vary greatly, they may be updated on a less frequent basis and the terminal may then only identify one or more peaks which are currently detected in a manner which reduces signalling. In some cases the identifier might be a quality value reported by the terminal, e.g. a quality measurement mean, average, peak etc. for the detected and reported peak as reported in the (e.g. first) quality report. In other cases, it may be an index or index-based identifier (e.g. 1 for a first peak, "2" for a second peak, etc.).

In some cases, the quality report can be transmitted in an RRC message and the further quality report can be transmitted in a Physical Uplink Control Channel "PUCCH" or Physical Uplink Shared Channel "PUSCH" transmission.

In some cases a first quality report that indicates the characteristics of the CQI distribution can be transmitted in an RRC message and a second quality report, that is of a different type to the first quality report, can be transmitted in a Physical Uplink Control Channel "PUCCH" or Physical Uplink Shared Channel "PUSCH" transmission. For example, the first quality report can indicate information on the peaks in a CQI distribution, for example the mean, variance, contribution etc. of each of the peaks (or reported peaks, if not all peaks are reported). In some cases, the number of peaks may also be reported and in other cases it might be implicit from the number of sets of peak information (channel quality indications) reported. The second quality report can be for example similar to a conventional CQI (channel quality indicator) which indicates the MCS that would be required to achieve a 10% BLER, based on a determination by the terminal.

In other words, in some cases the terminal may transmit both one or more channel quality indications, regarding corresponding one or more peaks in the distribution of channel quality measurements and, for example in a further report, a channel quality indicator (e.g. CQI) which indicates a recommended modulation and coding scheme for a predetermined block error rate target (e.g. 10% BLER target). The further report may be of a different type than the first quality report.

In a further example of operation of the invention, the terminal derives quality (e.g. CQI) measurements over a period of time (e.g. 10 seconds) and sends an RRC message as a first quality report, indicating the characteristics of the CQI distribution. It can be noted that over a 10 second period, if reference signals suitable for CQI measurements, such as channel state information reference signals (CSI-RS), are sent every slot (e.g. where a slot has a duration of 1ms or less), 10,000 CQI measurements can be performed by the terminal. The terminal can generate a histogram of CQI measurements with a reasonable accuracy with such a sample set size. Having made these measurements over a period of time, the terminal can send information on this CQI distribution, as described in other examples herein, in an RRC message. This can for example be an RRC message sent at connection setup or an RRC message sent during an ongoing connection. In addition, the UE can send legacy or conventional CQI messages as second quality reports, indicating the CQI that is measured at a particular time. These legacy CQI messages that are sent as second quality reports may be sent regularly or periodically, for example they may be sent every 5ms. In an example of operation, the terminal may make measurements and report, e.g. by a first quality report, that there are two peaks in the CQI distributio a lower quality peak with a mean of CQI = 3 and a variance of 0.1 a higher quality peak with a mean of CQI = 10 and a variance of 4

The terminal may then make regular quality measurements (e.g. CQI measurements) and report these to the base station as second quality reports. If the base station receives a second quality report from the UE with a value of CQI = 3, the base station could attribute a high degree of confidence in such a CQI report and thus schedule a future PDSCH with an MCS that corresponds directly to CQI = 3. This is because the base station can have a relatively high, confidence, based on the previously received distribution, that this PDSCH will be received by the UE at the target BLER. However, if the base station receives a second quality report with a value of CQI = 9, the base station may not attribute the same level of confidence to this CQI report, given that there is a large variance associated with the peak for CQI value 10. Accordingly, the base station may assume that, for CQI reports that are close to the mean of CQI = 10 (given that the terminal had previously indicated, via the first quality report, a high variance of CQI reports around a peak with a mean of CQI = 10), the confidence level associated with the CQI is lower. The base station may then apply a greater offset to the CQI report close to that second peak in order to achieve the BLER target. For example, the base station may determine to schedule the UE with a PDSCH that corresponds to CQI = 6 (i.e. the base station has applied an offset of 3 CQI points/steps to ensure that the PDSCH is reached with the target BLER).

Additionally or alternatively, the base station may be configured to, upon receipt of the further quality report indicating that the first peak is active, refer to the quality report for the first peak to determine one or more characteristics of the first peak based on the first channel quality indication.

In some cases, the terminal may be configured to transmit the quality report as a first report, where the quality report comprises one or more channel quality indication(s) and to transmit a second report. The second report comprises an identifier (e.g. identifying a peak or CQI value) thereby indicating to the base station that the identified peak is active (e.g. has been detected). As mentioned above, the first report may be transmitted via RRC signalling and the second report may be sent dynamically via PUCCH or PUSCH transmissions.

In some cases, after having received the first quality report from the terminal, where one or more peaks are reported to the base station, the base station can indicate to the terminal which peak should be selected for reporting on channel quality information. For example, the base station can identify the peak based on a CQI value (e.g. peak, mean, average, etc.) or based on an identifier, if provided. If the terminal makes a channel quality (e.g. CQI) measurement, it may only report if the measurement is associated with the peak.

It will be appreciated that the configuration for the terminal may be received from the base station. For example, the base station can transmit quality reporting configuration to the terminal and the terminal may then determine to report on the first peak based on the quality reporting configuration received from the base station.

The configuration may not be limited to the first peak. For example, the terminal may decide to report on a second peak based on the quality reporting configuration received from the base station, wherein the quality report comprises a second channel quality indication fora second subset of the channel quality measurements, the second subset of the channel quality measurements being associated with the second peak.

Such quality reporting configuration comprises one or more of: an instruction to report on a lowest quality peak of the distribution of the channel quality measurements; an instruction to report on a highest quality peak of the distribution of the channel quality measurements; an instruction to report on all peaks of the distribution of the channel quality measurements; an instruction to report on a predetermined maximum number of peaks of the distribution of the channel quality measurements; an instruction to alternate reports between two or more of the peaks of the distribution of the channel quality measurements; an instruction to report on a lowest quality peak of the distribution of the channel quality measurements using a first set of resources and to report on a highest quality peak of the distribution of the channel quality measurements using a second set of resources different from the first set of resources (e.g. non overlapping resources); an instruction to disregard any peak of the distribution of the channel quality measurements associated with a contribution factor of less than a predetermined threshold; an instruction to disregard any peak of the distribution of the channel quality measurements associated with a contribution factor of less than a predetermined fraction of a target block error rate for the terminal; an instruction to disregard one or more peaks of the distribution of the channel quality measurements when the cumulative contribution factor of peaks of lower quality is above a predetermined threshold; an instruction to disregard one or more peaks of the distribution of the channel quality measurements when the cumulative contribution factor of peaks of lower quality is above a predetermined fraction of a target block error rate for the terminal; an instruction to report on the lowest quality peaks of the distribution of the channel quality measurements associated with a cumulative contribution factor which is above a threshold (e.g. determined with respect to a BLER target or not); and an instruction to report on a predefined number of peaks and to select peaks with a greater contribution factor.

The base station taking a remedial measure may comprise the base station selecting a modulation and coding scheme for communicating with the terminal via the wireless interface based on the quality report and on the channel quality indication in respect of the first subset of the channel quality measurements. For example, the base station may be configured to determine an offset value from a first reference quality value based on the quality report and to derive the MCS from a second value, the second value being obtained by applying the offset value to the first reference quality value. In other cases, the reported information (from one or more reports) may enable the base station to determine an MCS which is expected to meet a BLER or other targets of the terminal. For example, in cases where the contribution or cumulative contribution of the reported peak(s) is over a threshold, the base station may be able to determine a quality value (e.g. CQI) associated with a BLER target based on the reported peak(s). In a case where a lowest peak (possibly after filtering of peaks with a contribution deemed too small) is reported with a contribution factor of 10% and where the BLER target of 10⁵, the base station may be able to derive a corresponding CQJ value without any information regarding higher peaks. From one perspective, the base station may be configured to take a remedial measure by selecting a modulation and coding scheme (for communicating with the terminal via the wireless interface) based on a reported channel quality indication in respect of channel quality measurements associated with a lowest quality peak reported by the terminal.

In an example mode of operation, once the base station has received a first quality report indicating the CQI distribution (e.g. including the number of peaks in the distribution and the relative characteristics of peaks in the distribution), the base station can indicate to the terminal to only report on CQI values in a second quality report around that peak. For example, the base station can indicate to the terminal to only report CQI values that are close to a lowest peak in the CQI distribution. For example, if the lowest peak in the CQI distribution is centred on a CQI value of 3 and the higher peak in the CQI distribution is centred on a CQI value of 10, the base station may indicate to the terminal to only report CQI centred on a CQI value of 3. If the terminal measures a CQI value of 7, the terminal would not report CQI, saving terminal power and physical resources on the air interface. If the terminal measures a CQI value of 3, the terminal would report this CQI value to the base station. This mode of operation could be useful if the base station has a policy of scheduling the terminal with an MCS that is not greater than an MCS corresponding to a CQI value of 5: the base station would then only need to know when the terminal experienced channel conditions that were worse than channel conditions associated with CQI = 5, i.e. it would only need to know about CQI reports that were associated with the lower peak. In a case where the UE is configured to report CQI periodically, if the base station does not receive a CQI report at one of the configured periodic times, it would understand that the CQI value measured by the UE corresponds to a CQI value that is not associated with a peak in the CQI distribution for which CQI reports were required. For example, if the UE is configured to periodically report CQI at times tl, t2, and t3 and the UE measures a CQI value of CQI=7 at tl, CQI=3 at t2 and CVI=8 at t3, the UE would report CQI = 3 at time t2 and would not send reports at times tl and t3. The base station would understand that at times tl and t3, the UE had measured CQI values associated with the higher peak in the CQI distribution and would further understand that at time t2, the UE had measured a CQI value associated with the lower peak.

As will be appreciated from the discussions above, the base station may take a remedial measure by selecting a modulation and coding scheme for communicating with the terminal via the wireless interface based on reported channel quality indication(s) in respect of channel quality measurements associated with peaks having a contribution over a predetermined threshold (where the threshold may be based on a BLER target for the terminal or not).

In some cases, the base station may be able to determine based on at least the reported information that a neighbouring base station is the expected source of lower quality measurements reported by the terminal. For example, the base station may identify a neighbouring base station as a source of interference on the wireless interface and communicate with the neighbouring base station to reduce the level of interference on the wireless interface. For example, it may do one or more of (i) instructing the neighbouring base station to reduce a transmitting power on one or more first frequency resources which (at least) overlaps with one or more second frequency resources used for communications on the wireless interface with the terminal, (ii) instructing the neighbouring base station to stop transmitting on one or more frequency resources used for communications on the wireless interface (e.g. overlapping the frequency resources used for communications on the wireless interface with the terminal); and coming to an agreement with the neighbouring base station on a transmission schedule for reducing the interference levels between the base station and the neighbouring base station. In cases where a neighbouring base station is identified as a source of lower quality measurements for the terminal (e.g. as interference), the base station may take measures so that the level of interference caused by the neighbouring base station is reduced, for example significantly reduced. In such cases, the base station may be able to select an MCS using a higher quality peak, ignoring a lower quality peak which is deemed caused by the neighbouring base station. Accordingly, not only can the reporting of peaks of quality measurements help identify the interference believed to be caused by a base station, it can also help the base station determine an appropriate transmission configuration and a level of transmission robustness which is based on quality measurements expected when the interference has stopped or reduced.

In some cases, the base station can receive from the terminal a channel quality measurement or indicator (e.g. CQI value). The base station can associate the received channel quality measurement or channel quality indicator with a particular peak previously reported by the terminal. The base station may then determine a modulation and coding scheme for the terminal based on the channel quality indication received from the terminal for the particular peak. For example, if the peak had a greater variance associated with it, the base station may apply a greater offset or make a more conservative determination for the MCS than if the variance had been smaller.

For example, the channel quality report comprising the channel quality indication regarding the distribution peak(s) may be sent using one or more RRC messages while the received channel quality measurement or indicator may be received using a channel quality indicator "CQI" transmission.

Figure 13 illustrates another example method in accordance with the present disclosure, namely a method of operating a terminal in a mobile telecommunications network, the network comprising the terminal and a base station configured to provide a wireless interface to the terminal. The method comprises making channel quality measurements for the wireless interface; determining that the distribution of the channel quality measurements comprises at least a low quality peak and a high quality peak, the low quality peak being associated with a lower quality of the wireless interface relative to the quality of the wireless interface associated with the high quality peak; determining to report on at least a first peak, the first peak being one of the low quality peak and high quality peak; and transmitting to the base station, a quality report comprising a first channel quality indication for a first subset of the channel quality measurements, the first subset of the channel quality measurements being associated with the first peak.

The teachings and techniques provided herein, in particular above in respect of Figure 12, apply equally to this example method.

Figure 14 illustrates a further example method in accordance with the present disclosure, namely a method of operating a base station in a mobile telecommunications network, the network comprising a terminal and the base station, wherein the base station comprises a transceiver element and controller configured to operate together to provide a wireless interface to the terminal. The method comprises receiving, from the terminal, a quality report comprising a first channel quality indication for a first subset of channel quality measurements, the first subset of the channel quality measurements being associated with a first peak of at least two peaks of the distribution of the channel quality measurements; and taking a remedial measure in response to receiving the quality report and based on the channel quality indication in respect of the first subset of the channel quality measurements.

Likewise, the teachings and techniques provided herein, in particular above in respect of Figure 12, apply equally to this example method. For identifying peaks in a distribution, different techniques may be applied. UEs can determine whether there is a peak in the CQI distribution by creating a histogram of CQI values and performing one of the following algorithms:

• a peak or mode can be identified based on a threshold being exceeded, and on the incidence level or distribution curve being above the threshold (on the y-axis of the distribution, which from one perspective can be seen as corresponding to a probability density function "PDF") for a lower CQI value and is below the threshold for a higher value of CQI. In other words, the incidence level was below the threshold for a first low CQI and as the CQI increases, the incidence level had gone over the threshold and then below the threshold.

• A peak or mode can be identified if the rate of change of the incidence level is positive for a lower value of CQI and changes to negative for a higher value of CQI. If appropriate (e.g. depending on the granularity at a CQI level), this may be determined after a smoothing function has been applied, with a view to flattening or smoothing the curve and reducing the occurrence of small bumps along the incidence level curve.

It will be appreciated that other techniques may be used to determine a peak or mode in a distribution, for example based on statistical techniques. Accordingly, the skilled person is not limited to these illustrative examples.

Various example implementations will be discussed as illustrative and implementations of the teachings and techniques of the present disclosure. These implementations are not intended to be limiting the scope of the invention as claimed.

Example 1

In this example, the CQI report is based on the peak in the CQI distribution that is centred around the lowest CQI or highest CQI value.

In one implementation, the reporting is based on the lowest CQI peak value. Operation according to this embodiment is shown in Figure 15 which illustrates an example of reporting on a CQI peak. The figure shows a two peak CQI distribution (similar to that of Figures 10 and 11) with peaks labelled as "A" and "B". For example, the lower peak in the distribution may be due to neighbour cell interference. According to this example, the UE identifies that the distribution has more than one peak and generates and sends a CQI report that is based on the mean and / or variance of the lower peak. For example, the CQI report is based on the values meani_ow and variancei_ow for peak A.

When the report is based on the lowest quality CQI value peak (e.g. peak "A" in Figure 15), the CQI report is based on the worst portion of the CQI distribution for the terminal. Said differently, the report is based on the portion of the CQI distribution which will support the lowest spectral efficiency communications. For communications which have a high reliability target (e.g. a correspondingly low BLER target), the base station might rely on the lowest quality peak(s) more heavily than on others.

The UE may also send a report based on the highest CQI value peak (only or in addition to the lower quality CQI reporting). In this example, the UE reports the statistics for the highest CQI value peak, e.g. on peak B if using the example in Figure 15.

For example, the base station may assume or determine that the peaks around lower CQI values are the result of interference. If thegNB has means to eliminate or reduce interference in the future (for example, by the use of inter-gNB coordination), then the CQI distribution that would be relevant for future scheduling decisions would be the portion of the CQI distribution based on the highest CQI value peak. Accordingly, the base station may rely on the higher quality peak reporting, even in cases where one or more lower quality peaks are presents and/or where a high reliability target is set for the terminal.

Example 2

In this example, the UE can report the number of peaks in the CQJ distribution. For example, if three peaks are detected, the terminal can report on all three peaks to the base station. If mean and variance are used for the reporting, mean and variance values can be reported for each peak in CQI reporting.

The gNB may then have a clearer understanding of the quality measured by the terminal and may schedule transmission accordingly, for example by selecting an appropriate MCS for communicating with the terminal and/or by co-ordinating with another base station with a view to reducing the level of interference experienced by the terminal.

In a case where only a single peak is detected and reported, the gNB can schedule in the legacy manner, where it may assume a single bell-curve distribution of all CQI values and may thus only account for the CQI value reported or the CQI value and the variance of the CQI value.

If however the UE detects and reports multiple peaks, the gNB can schedule based on CQI values reported for the lowest peak (at least). In one example the gNB may treat the lowest quality peak reported by the terminal as representative of all CQI values, thereby following a "worst case scenario" approach for scheduling.

As previously discussed, if the UE reports multiple peaks, the gNB may indicate to gNBs controlling neighbour cells that they are causing interference into the gNB's cell. The set of gNBs can then determine how to schedule in a manner that minimises interference (e.g. different gNBs use different sets of frequency resources for scheduling).

Example 3

In this example, the UE can report various statistics on each peak in the CQI distribution.

As mentioned above, the UE may be configured to report a mean value and a variance value for each peak in the CQI distribution. Additionally or alternatively, the UE may report on an average value, a mode or peak value or a median value.

The UE may in some cases report a contribution factor of value of the peak, illustrating the contribution of a peak in the incidence levels relative to the entire distribution of the incidence levels. This can be viewed as determining the contribution of the area under the peak relative to the total area under the curve of the incidence levels.

This type of information may be useful for the base station to make scheduling decisions. For example, if the gNB aims to achieve a 10% BLER target and the contribution of a peak is 10⁴, the base station can ignore that peak when determining MCS. On the other hand, for a 10⁵ BLER target and a contribution of 10² of a peak, the base station may take the peak into account when making scheduling decisions, e.g. when determining an appropriate MCS for the low BLER target.

Figure 16 illustrates another example of reporting on a CQI peak. In this example, the terminal makes measurements for the CQI and identifies that the CQI distribution includes two peaks A and B (similar to the peaks of Figure 15). The terminal may also identify that the peak A is associated with a contribution of 0.2 and that peak B is associated with a contribution of 0.8. Accordingly, the surface area under peak A (dotted area) represents about 20% of the total incidence of the measured CQI values while the surface area under peak B (the cross-hatched grid area) represents about 80% of the total incidence of the measured CQI values.

In such an example, and where additionally the UE reports the number of peaks identified, the UE may report the following:

Number of peaks = 2

Statistics of peak A: mean = meari_A, variance = variance_A, CDF contribution = 0.2 (oreo^)

Statistics of peak B: mean = mean_B, variance = variances, CDF contribution = 0.8 ( area_B )

As mentioned above, in some cases the UE will report on a peak in the CQI distribution where the contribution of the peak is above a threshold (where the threshold can for example be set in the specifications and/or signalled to the UE). For example, according to Figure 16:

• If threshold = 0.1 and the UE is configured to report the lowest quality peak, the UE would send reports based on peak A.

• If threshold = 0.3 and the UE is configured to report on the lowest quality peak, the UE would send reports based on peak B (as peak A has a contribution of 0.2 which is below the threshold).

In some examples, the threshold can be set relatively to the BLER target (e.g. if BLER target < 10%, the threshold could be set as 0.01).

In some examples, the threshold can refer to the sum of the contributions from lower quality peaks. For example, referring to Figure 16, if there were a further lower quality peak, peak X, to the left of peak A with a contribution of 0.05:

• If threshold = 0.3 and the UE is configured to report on the lowest quality peak, the UE would send reports based on peak B (as the sum of the contributions from peak X and peak A is 0.05 + 0.2 = 0.25, which is below the threshold).

• If threshold = 0.22 and the UE is configured to report the lowest quality peak, the UE would send reports based on peak A (as the contribution from peak X is below the threshold and the sum of the contributions from peaks X and A is 0.25, which is above the threshold). It is noteworthy that in cases where the terminal considers the individual contributions rather than a cumulative contribution of peaks, a 0.22 threshold would result in peak B being reported as peak A is under the threshold when considered individually.

When reporting on peak(s) depending on whether their cumulative contribution is above or below a threshold, the terminal may be configured to report on the lowest quality peaks whose cumulative contribution become above a threshold (e.g. peaks X and A in the 0.22 threshold example above) or may be configured to report on the highest quality peak of the lowest quality peaks whose cumulative contribution becomes above a threshold. As mentioned herein, the peaks to be reported may additionally be filtered to remove peaks whose contribution is considered negligible (e.g. of at least a fraction, such as a tenth, of the lowest expected BLER, which may be a 10⁵ BLER for URLLC traffic).

Accordingly, in some examples the UE can may send one or more of the following elements in its report: • An index or identifier for the peak, e.g. in the reported peaks or in the identified peaks (whether the peak is "peak A" or "peak B", whether the peak is the peak number two of the five reported peaks, etc.);

• A mean value for the peak (or another reference value);

• A variance value for the peak; and/or

• A contribution factor for the peak.

Example 4

In this example, the UE transmits reports based on the N largest peaks in the CQI distribution, with N >_1. In this context, largest can be determined based on a contribution factor for the peaks. For example, the UE may be configured to report on the two or three largest peaks of its distribution.

The reports may comprise statistics such as those discussed in respect of Example 3 above or in respect of other examples.

The value of N may be signalled to the UE in advance or pre-defined in specifications for the UE.

In some cases, the N biggest contributors may be reported to the base station regardless of their contribution but in other cases, a threshold as discussed above may be used to filter the peak reporting and to remove from the reporting peaks that have a contribution which is under (or not above) a threshold (where the threshold can be predefined or set based on the BLER target).

For example, for a threshold of 0.25 (or 25% contribution) and N= 2, the terminal may report only on peak B of Figure 16. On the other hand, for a threshold of 0.1 (or 10% contribution) and N= 2, the terminal may report on both peaks A and B.

Example 5

In this example, the UE can signal identities of peaks semi-statically and the activity of the peaks dynamically.

The UE can measure the CQJs (or other channel quality measure) and identify where the peaks in the CQJ distribution are. The locations of the multiple peaks in the CQI distribution are likely to be due to interference from neighbour cells. Hence, for a static UE, the locations of the peaks are expected to have limited change (since the position relative to the neighbour cells' transmissions are subject to less change).

In one example, the UE then signals the locations of the peaks in the CQJ distribution semi-statically to the gNB (e.g. via RRC signalling). The UE may also in some implementations signal the mean, variance and contribution of each of the peaks to the gNB in the semi-static (RRC) signalling.

When the UE sends a CQI measurement, it can then identify which peak is active and can then just send to the gNB a report that consists of an indication of which CQI distribution peak was active. This report can be sent dynamically (e.g. via PUCCH or PUSCH) and the base station can refer back to the report with the distribution for the peaks and the peaks' characteristics based on which peak the UE referred to. The gNB can then determine the mean, variance and CDF contribution of the CQI being reported based on a combination of the semi-static indication (e.g. RRC signalling) and the dynamic indications (e.g. CQI report). In some implementations, (and also in cases where the quality report is as discussed in Example 5 or in other examples or techniques of the present disclosure), the UE and/or gNB may be able to associate one or more peaks in the CQI distribution to other gNBs in the network, as peaks in the CQI distribution may sometimes be caused by interference from neighbouring gNBs. If the serving gNB has URLLC traffic, when low quality peaks are detected which are expected to be caused by a neighbouring gNB, the serving gNB may then negotiate with this interfering gNB. The negotiation may be aimed at:

• Causing the interfering gNB to cease transmitting on the resources until the serving gNB's high reliability or URLLC traffic is sent.

• Receiving information from the interfering gNB on when that interfering gNB is going to schedule transmissions in the future, for example for interference coordination purposes. The serving gNB can then avoid using those resources that are expected to suffer from interference caused by the neighbouring gNB. For example, the base station may schedule less sensitive communications (e.g. lower reliability or eMBB transmissions) on such resources and/or schedule URLLC transmissions using different resources which are expected to be less affected by the transmissions of the neighbouring gNB.

Example 6

In this example, different timing may be used depending on which peak the terminal is reporting on.

It will be appreciated that the signalling overhead caused by the sending of additional information in a CQI report may be viewed as undesirable. For example, transmitting reports on each peak in the CQJ distribution is expected to increase the amount CQI data to be transmitted. Accordingly, one or more of the following techniques may be used:

• A UE can provide the report of each peak in the CQI distribution at different times or in an alternating manner in order to reduce the overhead. For example, if two peaks A and B are reported, the UE may alternate between peaks A and B and use every other reporting opportunity to report on peak A and the other half of the reporting opportunities to report on peak B. The UE and base station can have a pre-agreed (e.g. configured) schedule for reporting on two or more peaks and the terminal may send a report about a single peak but change between the two or more peaks depending on which timing opportunity is considered.

• In cases where the index of the peak may not be derived implicitly, each report may be labelled with the index of the peak that it refers to. For example, if the terminal rotates between all peaks selected for reporting, the terminal may report on two peaks by sending reports for A-B-A-B-etc. and for three peaks with reports for A-B-C-A-B-C-etc. As alluded to above, in some cases the position or index of the peak may be implicitly signalled. The reporting opportunities may for example be each associated with a particular index. For three implicit indexes and three peaks to report, the terminal transmits reports for A-B-C-A-B-C- etc. In the same configuration but with two peaks to report, the terminal may transmit reports for A-B-[no report]-A-B-[no report]=etc., as the terminal does not have a peak to report as a third position peak (whichever peak ordering technique is used - see above).

• Each peak in the CQI distribution (again, depending on the peak ordering technique, see the various discussion above on this point) is associated with different physical resources. For example, the first peak in the distribution is associated with physical resources in radio frame 1, the second peak in the distribution is associated with physical resources in radio frame 2 etc. The set of physical resources used can wrap around. For example when the reporting wraps around every 4 radio frames, the first peak is reported in radio frames 1,5,9 etc, the second peak is reported in radio frames 2,6,10 etc.

• The resources for reporting channel quality indication(s) are preconfigured, for example carried by certain physical resources on the PUCCH or PUSCH channels. For example, some resources may be associated with a first / lowest quality peak and other resources associated with a highest quality peak which would enable the terminal to report on at least two peaks, without having to identify the peak specifically. The base station would be able to determine which peak is the lowest quality peak and which peak is the highest quality peak based on the resources used for transmitting the report.

In one example, the terminal can indicate to the base station that is it is capable of measuring a channel quality (e.g. CQI) distribution and to identify peaks in the distribution. In response, the base station may in some cases transmit to the terminal configuration information relating to the identification and/or reporting of peaks, as discussed herein.

Accordingly, teachings and techniques are provided herein, which enables a better management of channel quality measurement and reporting, in a manner which provides a better representation of the terminal's experience, while limiting the amount of signalling to be transmitted to the base station (compared to for example transmitting the quality / incidence curve to the base station).

In accordance with the present disclosure, terminals, base station and methods are provided, and circuitry for a terminal and circuitry for base station can also be provided.

As will be appreciated, the present disclosure is provided using current terminology and concepts as an illustration, but the present disclosure is not limited to these. For example, the references to a BLER or BLER target can be interpreted as references to a transmission reliability measure or transmission reliability target, respectively. The use of a BLER target corresponds to current systems but it is conceivable that future implementation will use a different transmission reliability measure (e.g. depending on whether the transmissions are for high reliable communications or not).

Additionally, while most of the examples have been illustrated using the CQI as a quality measurement, this is mostly for ease of understanding the teachings of the present disclosure and their applicability to current systems, the present disclosure is not limited to a CQI-only implementation. For example, an SNR or SINR measure may be used, or a measure of interference levels may be used instead (or in addition). The same teachings regarding distribution and high/low quality measurements apply to these other measurements. It is noteworthy that in the case of interference, the higher the peak, the more interference there is. Accordingly, the level of quality associated with an interference peak (e.g. relatively high or low quality) might be determined based on how far along the x-axis the peak can be found. A peak which is on the left hand side of the graph would indicate a higher quality (smaller level of interference) than a peak which is on the right hand side. This is the mirror of a CQI graph where lower quality peaks are on the lower end of the x-axis and higher quality peaks are on the higher end of the x- axis. Accordingly, the same principles and techniques can be applied to interference measurements.

It will be appreciated that while the present disclosure has in some respects focused on implementations in a 5G or NR network as such a network is expected to provide the primary use case at present, the same teachings and principles can also be applied to other wireless telecommunications systems. Thus, even though the terminology used herein is generally the same or similar to that of the 5G (or LTE) standards, the teachings are not limited to the present versions of 5G (or LTE) and could apply equally to any appropriate arrangement not based on 5G / LTE, for example any arrangement possibly compliant with any future version of an LTE, 5G, 6G or other standards - defined by the 3GPP standardisation groups or by other groups.

It will be appreciated that the principles described herein may be particularly targeted at certain types of terminals (communications devices), such as high reliability terminals and base stations (e.g. base station support high reliability communications). However, these techniques may also be applied more generally in respect of any types of communications device. For example and while the techniques are expected to be particularly useful for URLLC and/or loT devices or other low latency communications devices, the skilled person will appreciate that they can also be applied more generally, for example in respect of any type of communications device operating with a wireless link to the communication network, or for peer- to-peer transmissions (either transmissions ending at another node of the radio access network, e.g. a communication device or any other type of node in the network, or transmissions to or from the main or core network and going through a mesh network in the radio access network).

Additionally, the method steps discussed herein may be carried out in any suitable order. For example, steps may be carried out in an order which differs from an order used in the examples discussed above or from an indicative order used anywhere else for listing steps (e.g. in the claims), whenever possible or appropriate. Thus, in some cases, some steps may be carried out in a different order than listed (i.e. the order is not prescriptive), or simultaneously or in the same order. So long as an order for carrying any of the steps of any method discussed herein is technically feasible, it is explicitly encompassed within the present disclosure.

As used herein, transmitting information or a message to an element may involve sending one or more messages to the element and may involve sending part of the information separately from the rest of the information. The number of "messages" involved may also vary depending on the layer or granularity considered. For example, transmitting a message may involve using several resource elements in an LTE or NR environment such that several signals at a lower layer correspond to a single message at a higher layer. In addition, transmissions from one node to another may relate to the transmission of any one or more of user data, system information, control signalling and any other type of information to be transmitted. It will also be appreciated that some information may be notified or indicated implicitly rather than through the use of an explicit indicator.

Additionally, whenever an aspect is disclosed in respect of an apparatus or system, the teachings are also disclosed for the corresponding method and for the corresponding computer program. Likewise, whenever an aspect is disclosed in respect of a method, the teachings are also disclosed for any suitable corresponding apparatus or system as well as for the corresponding computer program. Additionally, it is also hereby explicitly disclosed that for any teachings relating to a method or a system where it has not been clearly specified which element or elements are configured to carry out a function or a step, any suitable element or elements that can carry out the function can be configured to carry out this function or step. For example, any one or more of a mobile node or network node may be configured accordingly if appropriate, so long as it is technically feasible and not explicitly excluded.

Whenever the expressions "greater than" or "smaller than" or equivalent are used herein, it is intended that they disclose both alternatives "and equal to" and "and not equal to" unless one alternative is expressly excluded. Further particular and preferred aspects of the present invention are set out in the accompanying independent and dependent claims. It will be appreciated that features of the dependent claims may be combined with features of the independent claims in combinations other than those explicitly set out in the claims, so long as they are technically plausible and feasible.

Thus, the foregoing discussion discloses and describes merely illustrative examples of the present disclosure and this disclosure is intended to be illustrative, but not limiting of the scope of the invention. The disclosure, including any readily discernible variants or equivalents of the teachings herein, define, in part, the scope of the foregoing claim terminology such that no inventive subject matter is dedicated to the public.

Also, while the examples above have been described using the example of communications between a terminal and a base station, the skilled person will appreciate that the communications may be between a terminal and one or more of: a base station, a TRP, a RRH (Remote Radio Head), a mobile terminal (e.g. connected through a side-link or PC5 interface), a relay, any radio access network node or more generally any other mobile node.

Also even in cases where the communications can viewed from the perspective of being between a terminal and a base station or mobile node, in some cases the communications may be sent through another network node, for example a relay or a next hop toward the (destination) network node.

Respective features of the present disclosure are defined by the following numbered clauses:

Clause 1. A method of managing channel quality information in a mobile telecommunications network, the network comprising a terminal and a base station configured to provide a wireless interface to the terminal, the method comprising: the terminal making channel quality measurements for the wireless interface; the terminal determining that the distribution of the channel quality measurements comprises at least a low quality peak and a high quality peak, the low quality peak being associated with a lower quality of the wireless interface relative to the quality of the wireless interface associated with the high quality peak; the terminal determining to report on at least a first peak, the first peak being one of the low quality peak and high quality peak; the terminal transmitting to the base station, a quality report comprising a first channel quality indication for a first subset of the channel quality measurements, the first subset of the channel quality measurements being associated with the first peak; and the base station taking a remedial measure in response to receiving the quality report and based on the channel quality indication in respect of the first subset of the channel quality measurements .

Clause 2. The method of Clause 1, wherein making channel quality measurements comprise measuring at least one of: signal-to-noise ratio "SNR", a signal-to-interference plus noise ratio "SINR", signal-to-noise plus distortion ratio "SNDR" and an interference level.

Clause 3. The method of any preceding Clause, wherein the first channel quality indication is one of a channel quality indicator "CQI", an interference level measurement and a SINR measurement.

Clause 4. The method of any preceding Clause, wherein the first channel quality indication identifies a first main channel quality value and a first variance value, wherein the first main channel quality value is one of an average, mean, mode, median and peak value for the first subset of the channel quality measurements and wherein the first variance value is a variance value for the first subset of the channel quality measurements. Clause 5. The method of any preceding Clause, wherein the terminal determines a first contribution factor for the first subset of the channel quality measurements, the contribution factor providing an indication of the contribution of the first subset of the channel quality measurements to the channel quality measurements.

Clause 6. The method of Clause 5, wherein the first channel quality indication comprises first contribution factor.

Clause 7. The method of any preceding Clause wherein the quality report comprises a second channel quality indication for a second subset of the channel quality measurements, the second subset of the channel quality measurements being associated with a second peak of the distribution of the channel quality measurements, the second peak being different from the first peak.

Clause 8. The method of Clause 7, wherein the second channel quality indication identifies a second main channel quality value and a second variance value, wherein the second main channel quality value is one of an average, mean, mode, median and peak value for the second subset of the channel quality measurements and wherein the second variance value is a variance value for the second subset of the channel quality measurements.

Clause 9. The method of any preceding Clause, comprising the terminal determining that the distribution of the channel quality measurements comprises a plurality of peaks, and the terminal transmitting to the base station, for each of the plurality of peaks, a respective channel quality indication for the respective subset of the channel quality measurements.

Clause 10. The method of Clause 9, wherein the respective channel quality indications are transmitted in the quality report and at least one further quality report.

Clause 11. The method of any preceding Clause wherein the quality report comprises channel quality information for some but not all of the channel quality measurements.

Clause 12. The method of any preceding Clause wherein the quality report does not comprise a second channel quality indication for a second subset of the channel quality measurements, the second subset of the channel quality measurements being associated with a second peak of the distribution of the channel quality measurements.

Clause 13. The method of any one of Clauses 1 to 8, comprising the terminal determining that the distribution of the channel quality measurements comprises a plurality of peaks , and the terminal transmitting to the base station, for each of the plurality of peaks, a respective channel quality indication for the respective subset of the channel quality measurements, wherein the respective channel quality indications are transmitted in the quality report.

Clause 14. The method of any preceding Clause, wherein the terminal determining to report on the first peak comprises one or more of the terminal: determining that the first peak is the lowest quality peak of the distribution of the channel quality measurements; determining that the first peak is the highest quality peak of the distribution of the channel quality measurements; determining that all peaks of the distribution of the channel quality measurements will be included in the report; determining that the first subset of the channel quality measurements is associated with one of a predetermined maximum number of peaks of the distribution of the channel quality measurements; selecting the first subset of the channel quality measurements based on a configuration to alternate reports between two or more of the peaks of the distribution of the channel quality measurements; disregarding one or more peaks of the distribution of the channel quality measurements associated with a contribution factor of less than a predetermined threshold; disregarding one or more peaks of the distribution of the channel quality measurements associated with a contribution factor of less than a predetermined fraction of a target block error rate for the terminal; disregarding one or more peaks of the distribution of the channel quality measurements when the cumulative contribution factor of peaks of lower quality is above a predetermined threshold; disregarding one or more peaks of the distribution of the channel quality measurements when the cumulative contribution factor of peaks of lower quality of the distribution is above a predetermined fraction of a target block error rate for the terminal; and selecting peaks of the distribution based on a predefined number of peaks and based on the selected peaks with the greatest contribution factors in the distribution.

Clause 15. The method of any preceding Clause, wherein the terminal transmitting to the base station, a quality report comprising a first channel quality indication for the first subset of the channel quality measurements comprises the terminal: selecting a set of resources for the first subset of resources for transmitting the quality report based on the position of the first peak in an ordered list of peaks of the distribution of the channel quality measurements ordered by level of quality associated with the quality measurements.

Clause 16. The method of any preceding Clause, wherein the quality report comprises an identifier for the first peak or first subset of the channel quality measurements, the method further comprising: the terminal transmitting, at a later point in time and to the base station, a further quality report, the further quality report comprising the identifier and indicating that the first peak is active.

Clause 17. The method of Clause 16, wherein the quality report is transmitted in a RRC message and wherein the further quality report is transmitted in a Physical Uplink Control Channel "PUCCH" or Physical Uplink Shared Channel "PUSCH" transmission.

Clause 18. The method of Clause 16 or 17 wherein, upon receipt of the further quality report indicating that the first peak is active, the base station referring to the quality report for the first peak to determine one or more characteristics of the first peak based on the first channel quality indication.

Clause 19. The method of any preceding Clause, comprising: the base station transmitting quality reporting configuration to the terminal; and the terminal determining to report on the first peak based on the quality reporting configuration received from the base station.

Clause 20. The method of Clause 19 comprising the terminal determining to report on a second peak based on the quality reporting configuration received from the base station, wherein the quality report comprises a second channel quality indication for a second subset of the channel quality measurements, the second subset of the channel quality measurements being associated with the second peak.

Clause 21. The method of Clause 19 or 20, wherein the quality reporting configuration comprises one or more of: an instruction to report on a lowest quality peak of the distribution of the channel quality measurements; an instruction to report on a highest quality peak of the distribution of the channel quality measurements; an instruction to report on all peaks of the distribution of the channel quality measurements; an instruction to report on a predetermined maximum number of peaks of the distribution of the channel quality measurements; an instruction to alternate reports between two or more of the peaks of the distribution of the channel quality measurements; an instruction to report on a lowest quality peak of the distribution of the channel quality measurements using a first set of resources and to report on a highest quality peak of the distribution of the channel quality measurements using a second set of resources different from the first set of resources; an instruction to disregard any peak of the distribution of the channel quality measurements associated with a contribution factor of less than a predetermined threshold; an instruction to disregard any peak of the distribution of the channel quality measurements associated with a contribution factor of less than a predetermined fraction of a target block error rate for the terminal; an instruction to disregard one or more peaks of the distribution of the channel quality measurements when the cumulative contribution factor of peaks of lower quality is above a predetermined threshold; and an instruction to disregard one or more peaks of the distribution of the channel quality measurements when the cumulative contribution factor of peaks of lower quality is above a predetermined fraction of a target block error rate for the terminal; an instruction to report on the lowest quality peak of the distribution of the channel quality measurements associated with a cumulative contribution factor which is above a threshold, an instruction to report on a predefined number of peaks and to select peaks with a greater contribution factor.

Clause 22. The method of any preceding Clause wherein the base station taking a remedial measure comprises the base station selecting a modulation and coding scheme for communicating with the terminal via the wireless interface based on the quality report and on the channel quality indication in respect of the first subset of the channel quality measurements.

Clause 23. The method of any preceding Clause wherein the base station taking a remedial measure comprises the base station selecting a modulation and coding scheme for communicating with the terminal via the wireless interface based on a reported channel quality indication in respect of channel quality measurements associated with a lowest quality peak reported by the terminal.

Clause 24. The method of any preceding Clause wherein the base station taking a remedial measure comprises the base station selecting a modulation and coding scheme for communicating with the terminal via the wireless interface based on one or more reported channel quality indications in respect of channel quality measurements associated with peaks having a contribution over a predetermined threshold.

Clause 25. The method of any preceding Clause wherein the base station taking a remedial measure comprises the base station identifying a neighbouring base station as a source of interference on the wireless interface and communicating with the neighbouring base station to reduce the level of interference on the wireless interface.

Clause 26. The method of Clause 25 wherein communicating with the neighbouring base station to reduce the level of interference on the wireless interface comprises one or more of: instructing the neighbouring base station to reduce a transmitting power on one or more first frequency resources which overlaps with one or more second frequency resources used for communications on the wireless interface; instructing the neighbouring base station to stop transmitting on one or more frequency resources used for communications on the wireless interface; and agreeing with the neighbouring base station on a transmission schedule for reducing the interference levels between the base station and the neighbouring base station.

Clause 27. A system for managing channel quality information in a mobile telecommunications network, the network comprising a terminal and a base station configured to provide a wireless interface to the terminal, the system comprising: the terminal, wherein the terminal is configured to make channel quality measurements for the wireless interface; determine that the distribution of the channel quality measurements comprises at least a low quality peak and a high quality peak, the low quality peak being associated with a lower quality of the wireless interface relative to the quality of the wireless interface associated with the high quality peak; determine to report on at least a first peak, the first peak being one of the low quality peak and high quality peak; and transmit to the base station, a quality report comprising a first channel quality indication for a first subset of the channel quality measurements, the first subset of the channel quality measurements being associated with the first peak; and the base station wherein the base station is configured to take a remedial measure in response to receiving the quality report and based on the channel quality indication in respect of the first subset of the channel quality measurements.

Clause 28. The system of Clause 27 wherein the system is further configured to implement the method of any one of Clauses 1 to 26.

Clause 29. A method of operating a terminal in a mobile telecommunications network, the network comprising the terminal and a base station configured to provide a wireless interface to the terminal, the method comprising: making channel quality measurements for the wireless interface; determining that the distribution of the channel quality measurements comprises at least a low quality peak and a high quality peak, the low quality peak being associated with a lower quality of the wireless interface relative to the quality of the wireless interface associated with the high quality peak; determining to report on at least a first peak, the first peak being one of the low quality peak and high quality peak; and transmitting to the base station, a quality report comprising a first channel quality indication for a first subset of the channel quality measurements, the first subset of the channel quality measurements being associated with the first peak.

Clause 30. The method of Clause 29 wherein making channel quality measurements comprises measuring at least one of: signal-to-noise ratio "SNR", a signal-to-interference plus noise ratio "SINR", signal-to-noise plus distortion ratio "SNDR" and an interference level.

Clause 31. The method of any one of Clause 29 to 30, wherein the first channel quality indication is one of a channel quality indicator "CQI", an interference level measurement and a SINR measurement. Clause 32. The method of any one of Clause 29 to 31, wherein the first channel quality indication identifies a first main channel quality value and a first variance value, wherein the first main channel quality value is one of an average, mean, mode, median and peak value for the first subset of the channel quality measurements and wherein the first variance value is a variance value for the first subset of the channel quality measurements.

Clause 33. The method of any one of Clause 29 to 32, further comprising determining a first contribution factor for the first subset of the channel quality measurements, the contribution factor providing an indication of the contribution of the first subset of the channel quality measurements to the channel quality measurements.

Clause 34. The method of Clause 33, wherein the first channel quality indication comprises first contribution factor.

Clause 35. The method of any one of Clause 29 to 34, wherein the quality report comprises a second channel quality indication for a second subset of the channel quality measurements, the second subset of the channel quality measurements being associated with a second peak of the distribution of the channel quality measurements, the second peak being different from the first peak. Clause 36. The method of Clause 35, wherein the second channel quality indication identifies a second main channel quality value and a second variance value, wherein the second main channel quality value is one of an average, mean, mode, median and peak value for the second subset of the channel quality measurements and wherein the second variance value is a variance value for the second subset of the channel quality measurements.

Clause 37. The method of any one of Clause 29 to 36, further comprising determining that the distribution of the channel quality measurements comprises a plurality of peaks, and transmitting to the base station, for each of the plurality of peaks, respective channel quality indication for the respective subset of the channel quality measurements.

Clause 38. The method of Clause 37, wherein the respective channel quality indications are transmitted in the quality report and at least one further quality report.

Clause 39. The method of any one of Clause 29 to 38, wherein the quality report comprise channel quality information for some but not all of the channel quality measurements.

Clause 40. The method of any one of Clause 29 to 39, wherein the quality report does not comprise a second channel quality indication for a second subset of the channel quality measurements, the second subset of the channel quality measurements being associated with a second peak of the distribution of the channel quality measurements.

Clause 41. The method of any one of Clause 29 to 36, further comprising determining that the distribution of the channel quality measurements comprises a plurality of peaks , and transmitting to the base station, for each of the plurality of peaks, a respective channel quality indication for the respective subset of the channel quality measurements, wherein the respective channel quality indications are transmitted in the quality report.

Clause 42. The method of any one of Clause 29 to 41, wherein determining to report on the first peak comprises one or more of: determining that the first peak is the lowest quality peak of the distribution of the channel quality measurements; determining that the first peak is the highest quality peak of the distribution of the channel quality measurements; determining that all peaks of the distribution of the channel quality measurements will be included in the report; determining that the first subset of the channel quality measurements is associated with one of a predetermined maximum number of peaks of the distribution of the channel quality measurements; selecting the first subset of the channel quality measurements based on a configuration to alternate reports between two or more of the peaks of the distribution of the channel quality measurements; disregarding one or more peaks of the distribution of the channel quality measurements associated with a contribution factor of less than a predetermined threshold; disregarding one or more peaks of the distribution of the channel quality measurements associated with a contribution factor of less than a predetermined fraction of a target block error rate for the terminal; disregarding one or more peaks of the distribution of the channel quality measurements when the cumulative contribution factor of peaks of lower quality is above a predetermined threshold; disregarding one or more peaks of the distribution of the channel quality measurements when the cumulative contribution factor of peaks of lower quality of the distribution is above a predetermined fraction of a target block error rate for the terminal; and selecting peaks of the distribution based on a predefined number of peaks and based on the selected peaks with the greatest contribution factors in the distribution. Clause 43. The method of any one of Clause 29 to 42, wherein transmitting to the base station, a quality report comprising a first channel quality indication for the first subset of the channel quality measurements comprises: selecting a set of resources for the first subset of resources for transmitting the quality report based on the position of the first peak in an ordered list of peaks of the distribution of the channel quality measurements ordered by level of quality associated with the quality measurements.

Clause 44. The method of any one of Clause 29 to 43, wherein the quality report comprises an identifier for the first peak or first subset of the channel quality measurements, the method further comprising: transmitting, at a later point in time and to the base station, a further quality report, the further quality report comprising the identifier and indicating that the first peak is active.

Clause 45. The method of Clause 44, wherein the quality report is transmitted in a RRC message and wherein the further quality report is transmitted in a Physical Uplink Control Channel "PUCCH" or Physical Uplink Shared Channel "PUSCH" transmission.

Clause 46. The method of any preceding Clause, comprising: receiving, from the base station, quality reporting configuration; and determining to report on the first peak based on the quality reporting configuration received from the base station.

Clause 47. The method of Clause 46 comprising determining to report on a second peak based on the quality reporting configuration received from the base station, wherein the quality report comprises a second channel quality indication for a second subset of the channel quality measurements, the second subset of the channel quality measurements being associated with the second peak.

Clause 48. The method of Clause 46 or 47, wherein the quality reporting configuration comprises one or more of: an instruction to report on a lowest quality peak of the distribution of the channel quality measurements; an instruction to report on a highest quality peak of the distribution of the channel quality measurements; an instruction to report on all peaks of the distribution of the channel quality measurements; an instruction to report on a predetermined maximum number of peaks of the distribution of the channel quality measurements; an instruction to alternate reports between two or more of the peaks of the distribution of the channel quality measurements; an instructions to report on a lowest quality peak of the distribution of the channel quality measurements using a first set of resources and to report on a highest quality peak of the distribution of the channel quality measurements using a second set of resources different from the first set of resources; an instruction to disregard any peak of the distribution of the channel quality measurements associated with a contribution factor of less than a predetermined threshold; an instruction to disregard any peak of the distribution of the channel quality measurements associated with a contribution factor of less than a predetermined fraction of a target block error rate for the terminal; an instruction to disregard one or more peaks of the distribution of the channel quality measurements when the cumulative contribution factor of peaks of lower quality is above a predetermined threshold; and an instruction to disregard one or more peaks of the distribution of the channel quality measurements when the cumulative contribution factor of peaks of lower quality is above a predetermined fraction of a target block error rate for the terminal; an instruction to report on the lowest quality peaks of the distribution of the channel quality measurements associated with a cumulative contribution factor which is above a threshold. an instruction to report on a predefined number of peaks and to select peaks with a greater contribution factor.

Clause 49. A terminal for use in a mobile telecommunications network, the network comprising the terminal and a base station configured to provide a wireless interface to the terminal, the terminal comprising a transceiver element and controller configured to operate together to: make channel quality measurements for the wireless interface; determine that the distribution of the channel quality measurements comprises at least a low quality peak and a high quality peak, the low quality peak being associated with a lower quality of the wireless interface relative to the quality of the wireless interface associated with the high quality peak; determine to report on at least a first peak, the first peak being one of the low quality peak and high quality peak; and transmit to the base station, a quality report comprising a first channel quality indication for a first subset of the channel quality measurements, the first subset of the channel quality measurements being associated with the first peak.

Clause 50. The terminal of Clause 49, further configured to implement the method of any one of Clauses 29 to 45.

Clause 51. Circuitry for a terminal for use in a mobile telecommunications network, the network comprising the terminal and a base station configured to provide a wireless interface to the terminal, wherein the circuitry comprises a controller element and a transceiver element configured to operate together to communicate with the base station via the wireless interface and wherein the controller element and the transceiver element are further configured to operate together to implement the method of any one of Clauses 29 to 48.

Clause 52. A method of operating a base station in a mobile telecommunications network, the network comprising a terminal and the base station, wherein the base station comprises a transceiver element and controller configured to operate together to provide a wireless interface to the terminal, the method comprising: receiving, from the terminal, a quality report comprising a first channel quality indication for a first subset of channel quality measurements, the first subset of the channel quality measurements being associated with a first peak of at least two peaks of the distribution of the channel quality measurements; and taking a remedial measure in response to receiving the quality report and based on the channel quality indication in respect of the first subset of the channel quality measurements.

Clause 53. The method of Clause 52, wherein the quality report comprises an identifier for the first peak or first subset of the channel quality measurements, the method further comprising: receiving, at a later point in time and from the terminal, a further quality report, the further quality report comprising the identifier and indicating that the first peak is active.

Clause 54. The method of Clause 53, wherein the quality report is received in a RRC message and wherein the further quality report is received in a Physical Uplink Control Channel "PUCCH" or Physical Uplink Shared Channel "PUSCH" transmission.

Clause 55. The method of Clause 53 or 54 further comprising, upon receipt of the further quality report indicating that the first peak is active, referring to the quality report for the first peak to determine one or more characteristics of the first peak based on the first channel quality indication.

Clause 56. The method of any of Clauses 52 to 55, comprising: transmitting quality reporting configuration to the terminal, the quality reporting configuration providing configuration for the terminal to determine to report on the first peak.

Clause 57. The method of Clause 56, wherein the quality reporting configuration comprises one or more of: an instruction to report on a lowest quality peak of the distribution of the channel quality measurements; an instruction to report on a highest quality peak of the distribution of the channel quality measurements; an instruction to report on all peaks of the distribution of the channel quality measurements; an instruction to report on a predetermined maximum number of peaks of the distribution of the channel quality measurements; an instruction to alternate reports between two or more of the peaks of the distribution of the channel quality measurements; an instructions to report on a lowest quality peak of the distribution of the channel quality measurements using a first set of resources and to report on a highest quality peak of the distribution of the channel quality measurements using a second set of resources different from the first set of resources; an instruction to disregard any peak of the distribution of the channel quality measurements associated with a contribution factor of less than a predetermined threshold; an instruction to disregard any peak of the distribution of the channel quality measurements associated with a contribution factor of less than a predetermined fraction of a target block error rate for the terminal; an instruction to disregard one or more peaks of the distribution of the channel quality measurements when the cumulative contribution factor of peaks of lower quality is above a predetermined threshold; and an instruction to disregard one or more peaks of the distribution of the channel quality measurements when the cumulative contribution factor of peaks of lower quality is above a predetermined fraction of a target block error rate for the terminal; an instruction to report on the lowest quality peaks of the distribution of the channel quality measurements associated with a cumulative contribution factor which is above a threshold, an instruction to report on a predefined number of peaks and to select peaks with a greater contribution factor.

Clause 58. The method of any one of Clauses 52 to 57, wherein taking a remedial measure comprises selecting a modulation and coding scheme for communicating with the terminal via the wireless interface based on the quality report and on the channel quality indication in respect of the first subset of the channel quality measurements.

Clause 59. The method of any one of Clauses 52 to 58, wherein taking a remedial measure comprises selecting a modulation and coding scheme for communicating with the terminal via the wireless interface based on a reported channel quality indication in respect of channel quality measurements associated with a lowest quality peak reported by the terminal.

Clause 60. The method of any one of Clauses 52 to 59 wherein taking a remedial measure comprises selecting a modulation and coding scheme for communicating with the terminal via the wireless interface based on reported one or more channel quality indications in respect of channel quality measurements associated with peaks having a contribution over a predetermined threshold.

Clause 61. The method of any one of Clauses 52 to 60, wherein taking a remedial measure comprises identifying a neighbouring base station as a source of interference on the wireless interface and communicating with the neighbouring base station to reduce the level of interference on the wireless interface.

Clause 62. The method of Clause 61 wherein communicating with the neighbouring base station to reduce the level of interference on the wireless interface comprises one or more of: instructing the neighbouring base station to reduce a transmitting power on one or more first frequency resources which overlaps with one or more second frequency resources used for communications on the wireless interface; instructing the neighbouring base station to stop transmitting on one or more frequency resources used for communications on the wireless interface; and agreeing with the neighbouring base station on a transmission schedule for reducing the interference levels between the base station and the neighbouring base station.

Clause 63. A base station for use in a mobile telecommunications network, the network comprising a terminal and the base station, wherein the base station comprises a transceiver element and controller configured to operate together to provide a wireless interface to the terminal, and to: receive, from the terminal, a quality report comprising a first channel quality indication for a first subset of channel quality measurements, the first subset of the channel quality measurements being associated with a first peak of at least two peaks of the distribution of the channel quality measurements; and take a remedial measure in response to receiving the quality report and based on the channel quality indication in respect of the first subset of the channel quality measurements.

Clause 64. The base station of Clause 63 being further configured to implement the method of any of Clauses 52 to 62.

Clause 65. Circuitry for a base station for use in a mobile telecommunications network, the network comprising a terminal and the base station, wherein the circuitry comprises a controller element and a transceiver element configured to operate together to provide a wireless interface to the terminal, wherein the controller element and the transceiver element are further configured to operate together to implement the method of any one of claims 52 to 64.

Clause 66. Any preceding Clause wherein the wireless interface is in accordance with one or more of: a 3GPP radio access technology, a Long Term Evolution "LTE" technology, a New Radio "NR" technology, a 4G technology, a 5G technology, a 6G technology and a mobile network radio access technology.

References

[1] RP-182090, "Revised SID: Study on NR Industrial Internet of Things (loT)," 3GPP RAN#81.

[2] Holma H. and Toskala A, "LTE for UMTS OFDMA and SC-FDMA based radio access”, John Wiley and Sons, 2009

[3] 3GPP TS 38.321, "Medium Access Control (MAC) protocol specification (Rel-15)", vl5.3.0

[4] 3GPP Rl-2103956, "Feature lead summary #4 on CSI feedback enhancements for enhanced URLLC/lloT," Moderator (InterDigital), RANl#104e-bis

Claims

Claims:

1. A method of managing channel quality information in a mobile telecommunications network, the network comprising a terminal and a base station configured to provide a wireless interface to the terminal, the method comprising: the terminal making channel quality measurements for the wireless interface; the terminal determining that the distribution of the channel quality measurements comprises at least a low quality peak and a high quality peak, the low quality peak being associated with a lower quality of the wireless interface relative to the quality of the wireless interface associated with the high quality peak; the terminal determining to report on at least a first peak, the first peak being one of the low quality peak and high quality peak; the terminal transmitting to the base station, a quality report comprising a first channel quality indication for a first subset of the channel quality measurements, the first subset of the channel quality measurements being associated with the first peak; and the base station taking a remedial measure in response to receiving the quality report and based on the channel quality indication in respect of the first subset of the channel quality measurements.

2. The method of claim 1, wherein making channel quality measurements comprise measuring at least one of: signal-to-noise ratio "SNR", a signal-to-interference plus noise ratio "SI NR", signal-to-noise plus distortion ratio "SNDR" and an interference level.

3. The method of claim 1, wherein the first channel quality indication is one of a channel quality indicator "CQI", an interference level measurement and a SINR measurement.

4. The method of claim 1, wherein the first channel quality indication identifies a first main channel quality value and a first variance value, wherein the first main channel quality value is one of an average, mean, mode, median and peak value for the first subset of the channel quality measurements and wherein the first variance value is a variance value for the first subset of the channel quality measurements.

5. The method of claim 1, wherein the terminal determines a first contribution factor for the first subset of the channel quality measurements, the contribution factor providing an indication of the contribution of the first subset of the channel quality measurements to the channel quality measurements.

6. The method of claim 5, wherein the first channel quality indication comprises first contribution factor.

7. The method of claim 1 wherein the quality report comprises a second channel quality indication for a second subset of the channel quality measurements, the second subset of the channel quality measurements being associated with a second peak of the distribution of the channel quality measurements, the second peak being different from the first peak.

8. The method of claim 7, wherein the second channel quality indication identifies a second main channel quality value and a second variance value, wherein the second main channel quality value is one of an average, mean, mode, median and peak value for the second subset of the channel quality measurements and wherein the second variance value is a variance value for the second subset of the channel quality measurements.

9. The method of claim 1, comprising the terminal determining that the distribution of the channel quality measurements comprises a plurality of peaks, and the terminal transmitting to the base station, for each of the plurality of peaks, a respective channel quality indication for the respective subset of the channel quality measurements.

10. The method of claim 9, wherein the respective channel quality indications are transmitted in the quality report and at least one further quality report.

11. The method of claim 1 wherein the quality report comprises channel quality information for some but not all of the channel quality measurements.

12. The method of claim 1 wherein the quality report does not comprise a second channel quality indication for a second subset of the channel quality measurements, the second subset of the channel quality measurements being associated with a second peak of the distribution of the channel quality measurements.

13. The method of claim 1, comprising the terminal determining that the distribution of the channel quality measurements comprises a plurality of peaks , and the terminal transmitting to the base station, for each of the plurality of peaks, a respective channel quality indication for the respective subset of the channel quality measurements, wherein the respective channel quality indications are transmitted in the quality report.

14. The method of claim 1, wherein the terminal determining to report on the first peak comprises one or more of the terminal: determining that the first peak is the lowest quality peak of the distribution of the channel quality measurements; determining that the first peak is the highest quality peak of the distribution of the channel quality measurements; determining that all peaks of the distribution of the channel quality measurements will be included in the report; determining that the first subset of the channel quality measurements is associated with one of a predetermined maximum number of peaks of the distribution of the channel quality measurements; selecting the first subset of the channel quality measurements based on a configuration to alternate reports between two or more of the peaks of the distribution of the channel quality measurements; disregarding one or more peaks of the distribution of the channel quality measurements associated with a contribution factor of less than a predetermined threshold; disregarding one or more peaks of the distribution of the channel quality measurements associated with a contribution factor of less than a predetermined fraction of a target block error rate for the terminal; disregarding one or more peaks of the distribution of the channel quality measurements when the cumulative contribution factor of peaks of lower quality is above a predetermined threshold; disregarding one or more peaks of the distribution of the channel quality measurements when the cumulative contribution factor of peaks of lower quality of the distribution is above a predetermined fraction of a target block error rate for the terminal; and selecting peaks of the distribution based on a predefined number of peaks and based on the selected peaks with the greatest contribution factors in the distribution.

15. The method of claim 1, wherein the terminal transmitting to the base station, a quality report comprising a first channel quality indication for the first subset of the channel quality measurements comprises the terminal: selecting a set of resources for the first subset of resources for transmitting the quality report based on the position of the first peak in an ordered list of peaks of the distribution of the channel quality measurements ordered by level of quality associated with the quality measurements.

16. The method of claim 1, wherein the quality report comprises an identifier for the first peak or first subset of the channel quality measurements, the method further comprising: the terminal transmitting, at a later point in time and to the base station, a further quality report, the further quality report comprising the identifier and indicating that the first peak is active.

17. The method of claim 16, wherein the quality report is transmitted in a RRC message and wherein the further quality report is transmitted in a Physical Uplink Control Channel "PUCCH" or Physical Uplink Shared Channel "PUSCH" transmission.

18. The method of claim 16 further comprising, upon receipt of the further quality report indicating that the first peak is active, the base station referring to the quality report for the first peak to determine one or more characteristics of the first peak based on the first channel quality indication.

19. The method of claim 1, comprising: the base station transmitting quality reporting configuration to the terminal; and the terminal determining to report on the first peak based on the quality reporting configuration received from the base station.

20. The method of claim 19 comprising the terminal determining to report on a second peak based on the quality reporting configuration received from the base station, wherein the quality report comprises a second channel quality indication for a second subset of the channel quality measurements, the second subset of the channel quality measurements being associated with the second peak.

21. The method of claim 19, wherein the quality reporting configuration comprises one or more of: an instruction to report on a lowest quality peak of the distribution of the channel quality measurements; an instruction to report on a highest quality peak of the distribution of the channel quality measurements; an instruction to report on all peaks of the distribution of the channel quality measurements; an instruction to report on a predetermined maximum number of peaks of the distribution of the channel quality measurements; an instruction to alternate reports between two or more of the peaks of the distribution of the channel quality measurements; an instruction to report on a lowest quality peak of the distribution of the channel quality measurements using a first set of resources and to report on a highest quality peak of the distribution of the channel quality measurements using a second set of resources different from the first set of resources; an instruction to disregard any peak of the distribution of the channel quality measurements associated with a contribution factor of less than a predetermined threshold; an instruction to disregard any peak of the distribution of the channel quality measurements associated with a contribution factor of less than a predetermined fraction of a target block error rate for the terminal; an instruction to disregard one or more peaks of the distribution of the channel quality measurements when the cumulative contribution factor of peaks of lower quality is above a predetermined threshold; and an instruction to disregard one or more peaks of the distribution of the channel quality measurements when the cumulative contribution factor of peaks of lower quality is above a predetermined fraction of a target block error rate for the terminal; an instruction to report on the lowest quality peak of the distribution of the channel quality measurements associated with a cumulative contribution factor which is above a threshold. an instruction to report on a predefined number of peaks and to select peaks with a greater contribution factor.

22. The method of claim 1 wherein the base station taking a remedial measure comprises the base station selecting a modulation and coding scheme for communicating with the terminal via the wireless interface based on the quality report and on the channel quality indication in respect of the first subset of the channel quality measurements.

23. The method of claim 1 wherein the base station taking a remedial measure comprises the base station selecting a modulation and coding scheme for communicating with the terminal via the wireless interface based on a reported channel quality indication in respect of channel quality measurements associated with a lowest quality peak reported by the terminal.

24. The method of claim 1 wherein the base station taking a remedial measure comprises the base station selecting a modulation and coding scheme for communicating with the terminal via the wireless interface based on one or more reported channel quality indications in respect of channel quality measurements associated with peaks having a contribution over a predetermined threshold.

25. The method of claim 1 wherein the base station taking a remedial measure comprises the base station identifying a neighbouring base station as a source of interference on the wireless interface and communicating with the neighbouring base station to reduce the level of interference on the wireless interface.

26. The method of claim 25 wherein communicating with the neighbouring base station to reduce the level of interference on the wireless interface comprises one or more of: instructing the neighbouring base station to reduce a transmitting power on one or more first frequency resources which overlaps with one or more second frequency resources used for communications on the wireless interface; instructing the neighbouring base station to stop transmitting on one or more frequency resources used for communications on the wireless interface; and agreeing with the neighbouring base station on a transmission schedule for reducing the interference levels between the base station and the neighbouring base station.

27. A system for managing channel quality information in a mobile telecommunications network, the network comprising a terminal and a base station configured to provide a wireless interface to the terminal, the system comprising: the terminal, wherein the terminal is configured to make channel quality measurements for the wireless interface; determine that the distribution of the channel quality measurements comprises at least a low quality peak and a high quality peak, the low quality peak being associated with a lower quality of the wireless interface relative to the quality of the wireless interface associated with the high quality peak; determine to report on at least a first peak, the first peak being one of the low quality peak and high quality peak; and transmit to the base station, a quality report comprising a first channel quality indication for a first subset of the channel quality measurements, the first subset of the channel quality measurements being associated with the first peak; and the base station wherein the base station is configured to take a remedial measure in response to receiving the quality report and based on the channel quality indication in respect of the first subset of the channel quality measurements.

28. A method of operating a terminal in a mobile telecommunications network, the network comprising the terminal and a base station configured to provide a wireless interface to the terminal, the method comprising: making channel quality measurements for the wireless interface; determining that the distribution of the channel quality measurements comprises at least a low quality peak and a high quality peak, the low quality peak being associated with a lower quality of the wireless interface relative to the quality of the wireless interface associated with the high quality peak; determining to report on at least a first peak, the first peak being one of the low quality peak and high quality peak; and transmitting to the base station, a quality report comprising a first channel quality indication for a first subset of the channel quality measurements, the first subset of the channel quality measurements being associated with the first peak.

29. A terminal for use in a mobile telecommunications network, the network comprising the terminal and a base station configured to provide a wireless interface to the terminal, the terminal comprising a transceiver element and controller configured to operate together to: make channel quality measurements for the wireless interface; determine that the distribution of the channel quality measurements comprises at least a low quality peak and a high quality peak, the low quality peak being associated with a lower quality of the wireless interface relative to the quality of the wireless interface associated with the high quality peak; determine to report on at least a first peak, the first peak being one of the low quality peak and high quality peak; and transmit to the base station, a quality report comprising a first channel quality indication for a first subset of the channel quality measurements, the first subset of the channel quality measurements being associated with the first peak.

30. Circuitry for a terminal for use in a mobile telecommunications network, the network comprising the terminal and a base station configured to provide a wireless interface to the terminal, wherein the circuitry comprises a controller element and a transceiver element configured to operate together to communicate with the base station via the wireless interface and wherein the controller element and the transceiver element are further configured to operate together to implement the method of claim 28.

31. A method of operating a base station in a mobile telecommunications network, the network comprising a terminal and the base station, wherein the base station comprises a transceiver element and controller configured to operate together to provide a wireless interface to the terminal, the method comprising: receiving, from the terminal, a quality report comprising a first channel quality indication for a first subset of channel quality measurements, the first subset of the channel quality measurements being associated with a first peak of at least two peaks of the distribution of the channel quality measurements; and taking a remedial measure in response to receiving the quality report and based on the channel quality indication in respect of the first subset of the channel quality measurements.

32. A base station for use in a mobile telecommunications network, the network comprising a terminal and the base station, wherein the base station comprises a transceiver element and controller configured to operate together to provide a wireless interface to the terminal, and to: receive, from the terminal, a quality report comprising a first channel quality indication for a first subset of channel quality measurements, the first subset of the channel quality measurements being associated with a first peak of at least two peaks of the distribution of the channel quality measurements; and take a remedial measure in response to receiving the quality report and based on the channel quality indication in respect of the first subset of the channel quality measurements.

33. Circuitry for a base station for use in a mobile telecommunications network, the network comprising a terminal and the base station, wherein the circuitry comprises a controller element and a transceiver element configured to operate together to provide a wireless interface to the terminal, wherein the controller element and the transceiver element are further configured to operate together to implement the method of claim 31.