WO2023078523A1

WO2023078523A1 - Efficient radio resource measurements based on client device recommendation

Info

Publication number: WO2023078523A1
Application number: PCT/EP2021/080318
Authority: WO
Inventors: Salah Eddine HAJRI; Gustaf Claeson; Thorsten Schier; Rama Kumar MOPIDEVI
Original assignee: Huawei Technologies Co., Ltd.
Priority date: 2021-11-02
Filing date: 2021-11-02
Publication date: 2023-05-11
Also published as: EP4406294A1

Abstract

The invention is related to radio resource measurements based on client device recommendations. A solution is provided which allow a client device to provide recommended radio resource measurement (RRM) information to a network access node or coordinator client device and to obtain a recommendation reply indicating whether the recommended RRM information is to be activated or not. Knowledge at the client device side about channel and interference conditions can hence be provided to and used by the network to adapt the RRM configuration of the client device to current channel conditions. Thereby, more flexible and efficient RRMs are provided and the network performance hence can be improved.

Description

EFFICIENT RADIO RESOURCE MEASUREMENTS BASED ON CLIENT DEVICE RECOMMENDATION

TECHNICAL FIELD

The invention relates to radio resource measurements based on client device recommendations. Embodiments of the invention provides a client device configured to transmit recommended radio resource measurement (RRM) information and a network access node or coordinator client device configured to transmit a recommendation reply indicating whether the recommended RRM information is to be activated or not. Furthermore, the invention relates to corresponding methods and a computer program.

BACKGROUND

One of the key enablers of the performance of 5G is new radio (NR) capability to leverage the radio link diversity in spatial, frequency and time domains. This is achievable thanks to advanced beamforming, carrier aggregation, multi-transmission and reception point (TRP) transmission, link adaptation and resource allocation and/or scheduling, among others.

To maintain the radio link quality, timely and accurate radio resource measurements (RRMs) are needed. RRMs are used for cross link interference measurements, uplink (UL) precoder selection, downlink (DL) precoder selection, transmission/reception UL/DL transmission configuration indication (TCI) states indication and/or selection, modulation coding scheme (MCS) selection, link adaptation, power control, phase tracking, among others.

Given the importance of RRMs it has been a focus of the 5G standardization effort in each of the releases so far, i.e. Rel-15, Rel-16 and Rel-17. This trend is expected to continue as more use cases and features are included.

In 5G NR Rel-17, machine learning (ML)Zartificial intelligence (Al) for radio access network (RAN) is one of the new study items and is expected to be a critical feature in future NR releases. The considered use cases, include load balancing, network energy saving and mobility optimization. In Rel-18 and beyond, the work on ML/AI for RAN is expected to continue and to address a wider scope including additional challenges and/or constraints related to the physical layer. SUMMARY

An objective of embodiments of the invention is to provide a solution which mitigates or solves the drawbacks and problems of conventional solutions.

Another objective of embodiments of the invention is to improve the efficiency and flexibility of RRMs based on information available in the client device.

The above and further objectives are solved by the subject matter of the independent claims. Further embodiments of the invention can be found in the dependent claims.

According to a first aspect of the invention, the above mentioned and other objectives are achieved with a client device for a communication system, the client device being configured to transmit a recommendation message, the recommendation message indicating a recommended radio resource measurement, RRM, information; receive a recommendation reply message, the recommendation reply message indicating whether the recommended RRM information is to be activated or not; and activate a RRM configuration based on the recommendation reply message.

The RRM configuration which is activated is based on the indication in the recommendation reply message and may be a new RRM configuration, an updated RRM configuration or a current/active RRM configuration.

An advantage of the client device according to the first aspect is that the client device can provide recommended RRM information dynamically and hence propose changes to an active RRM configuration. The recommended RRM information can be based on knowledge about channel and interference conditions only available at the client device side. By providing the recommended RRM information, this knowledge can be shared and used to update the RRM configuration for the client device, without inducing ambiguity at the network side. The RRMs can thereby be tailored to the actual channel conditions as experience by the client device which will ultimately result in better efficiency of the system. Furthermore, the recommendation reply message provides means to approve or override the recommendation from the client device, allowing e.g. a network access node to override the recommendation if the proposed change would affect other client devices negatively.

In an implementation form of a client device according to the first aspect, the client device is further configured to transmit the recommendation message upon determining that a trigger requirement associated with the RRM information is fulfilled.

An advantage with this implementation form is that triggers can be defined such that recommended RRM information can be provided when the client device detects or predicts changes in the channel conditions which would benefit from changes in the RRMs. Thereby, improved RRM efficiency and reactivity can be achieved.

In an implementation form of a client device according to the first aspect, the trigger requirement is a radio event associated with a timer, a counter, a measurement threshold, and/or a performance quantity.

An advantage with this implementation form is that the client device can detect or predict critical radio events and its parameters and propose RRM changes to adapt the RRMs to the radio event, thereby improving the efficiency of the RRMs.

In an implementation form of a client device according to the first aspect, the client device is further configured to receive a recommendation configuration message previous to transmitting the recommendation message, the recommendation configuration message indicating radio resources for transmitting the recommendation message.

An advantage with this implementation form is that the network can dynamically configure and adapt the radio resources dedicated for transmitting the recommendation message. This may e.g. result in improved resource utilization and reduced timeline for the recommendation message which enables faster network reaction to critical radio events.

In an implementation form of a client device according to the first aspect, the recommendation configuration message further indicates one or more in the group comprising: a set of valid recommended RRM information, a set of trigger requirements for transmitting the recommendation message, a set of radio resources in which the recommendation message is transmitted, and a set of radio resources in which the recommendation reply message is received.

In an implementation form of a client device according to the first aspect, the client device is configured to transmit a recommendation capability message, the recommendation capability message indicating RRM recommendation capabilities supported by the client device upon reception of a RRM capability enquiry message.

An advantage with this implementation form is that client devices with different capabilities may have different supported recommendation parameters in the recommendation configuration message. The recommendation capability message enables the network to tailor recommendation configuration to client device requirements and capabilities.

In an implementation form of a client device according to the first aspect, the recommendation reply message further indicates a time offset for activation of the recommended RRM information, and the client device is further configured to activate the recommended RRM information based on the time offset.

An advantage with this implementation form is that the updated RRM configuration, if any, becomes active at the same time at both the client device and at the network side. This will enable to avoid any ambiguity between the client device and the network in the expected measurements and reporting.

In an implementation form of a client device according to the first aspect, the recommended RRM information indicates one or more in the group comprising: a RRM configuration, a RRM model parameter, a RRM model, a RRM parameter, and a RRM format.

Depending on the RRM configuration, for which recommendation is enabled, the client device may recommend changing the entire configuration or specific parameters or the format of quantities within the configuration.

An advantage with this implementation form is that the network can tailor RRM recommendation complexity and format depending on UE RRM capabilities and the RRM in question.

In an implementation form of a client device according to the first aspect, the recommended RRM information indicates any one of: a channel state information reporting parameter or configuration, a channel state information quantity format or parameter, a reference signal configuration or mapping parameter, or a RRM model or model parameter.

An advantage with this implementation form is that the client device can detect the changes in the radio environment, e.g. based on reference signals measurements, and recommend changing channel state information reporting or reference signal configurations in order to adapt to new channel conditions. Such changes may include acceleration or deceleration of the client device mobility. Consequently, the client device may recommend higher period for channel state information reporting, in case it detects deceleration or lower Doppler effect, or lower period for channel state information reporting, in case it detects acceleration or higher Doppler effect. Similarly, the client device may recommend low density downlink reference signal in the frequency domain, if it detects a Line-of-Sight dominated channel.

In an implementation form of a client device according to the first aspect, the client device is further configured to transmit the recommendation message to a network access node or a coordinator client device; and receive the recommendation reply message from the network access node or the coordinator client device.

The coordinator client device may be considered as a client device configured in a sidelink context as a coordinator which may imply that the coordinator client device has been given credentials to adapt the RRM configuration for other client devices.

An advantage with this implementation form is that RRM configurations for client devices at the edge or out of the network coverage may updated through a client device, designated as a coordinator, with better coverage conditions. Additionally, RRM recommendation among client devices, enables insight transfer between client devices. This will ultimately spread the load of RRMs across client devices, and hence reducing the needed RRM by individual client devices.

In an implementation form of a client device according to the first aspect, the recommendation message and/or the recommendation reply message is a L1 or a L2 signalling message. An advantage with this implementation form is that the recommendation message and/or the recommendation reply message have a fast timeline, reducing the delay needed to adapt RRM to the actual radio environment conditions. Recommendation message may be transmitted as part of uplink (UL) control information or UL MAC CE. Recommendation reply message may be transmitted in downlink (DL) control information or DL MAC CE.

According to a second aspect of the invention, the above mentioned and other objectives are achieved with a network access node or a coordinator client device for a communication system, the network access node or the coordinator client device being configured to receive a recommendation message from a client device, the recommendation message indicating a recommended RRM information; transmit a recommendation reply message to the client device, the recommendation reply message indicating whether the recommended RRM information is to be activated or not.

An advantage of the network access node or the coordinator client device according to the second aspect is that the client device can provide recommended RRM information dynamically and hence propose changes to an active RRM configuration. The recommended RRM information can be based on knowledge about channel and interference conditions only available at the client device side. By providing the recommended RRM information, this knowledge can be shared and used to update the RRM configuration for the client device, without inducing ambiguity at the network side. The RRMs can thereby be tailored to the actual channel conditions as experience by the client device which will ultimately result in better efficiency of the system. Furthermore, the recommendation reply message provides means to approve or override the recommendation from the client device, allowing e.g. a network access node to override the recommendation if the proposed change would affect other client devices negatively.

In an implementation form of a network access node or a coordinator client device according to the second aspect, the network access node or the coordinator client device are further configured to transmit a recommendation configuration message to the client device previous to receiving the recommendation message, the recommendation capability message indicating radio resources for transmitting the recommendation message.

In an implementation form of a network access node or a coordinator client device according to the second aspect, the recommendation configuration message further indicates one or more in the group comprising: a set of valid recommended RRM information, a set of trigger requirements for transmitting the recommendation message, a set of radio resources in which the recommendation message is transmitted, and a set of radio resources in which the recommendation reply message is received.

In an implementation form of a network access node or a coordinator client device according to the second aspect, the network access node or the coordinator client device are further configured to transmit a RRM capability enquiry message to the client device, RRM capability enquiry message indicating an enquiry about RRM recommendation capabilities supported by the client device; and receive a recommendation capability message from the client device, the recommendation capability message indicating RRM recommendation capabilities supported by the client device.

In an implementation form of a network access node or a coordinator client device according to the second aspect, the recommendation reply message further indicates a time offset for activation of the recommendation RRM information.

An advantage with this implementation form is that the updated RRM configuration, if any, becomes active at the same time at both the client device and at the network side. This will enable to avoid any ambiguity between the client device and the network in the expected measurements and reporting. In an implementation form of a network access node or a coordinator client device according to the second aspect, the recommended RRM information indicates one or more in the group comprising: a RRM configuration, a RRM model parameter, a RRM model, a RRM parameter, and a RRM format.

In an implementation form of a network access node or a coordinator client device according to the second aspect, the recommended RRM information indicates any one of: a channel state information reporting parameter or configuration, a channel state information quantity format or parameter, a reference signal configuration or mapping parameter, or a RRM model or model parameter.

In an implementation form of a network access node or a coordinator client device according to the second aspect, the recommendation message and/or the recommendation reply message is a L1 or a L2 signalling message.

An advantage with this implementation form is that the recommendation message and/or the recommendation reply message have a fast timeline, reducing the delay needed to adapt RRM to the actual radio environment conditions. Recommendation message may be transmitted as part of uplink (UL) control information or UL MAC CE. Recommendation reply message may be transmitted in downlink (DL) control information or DL MAC CE.

According to a third aspect of the invention, the above mentioned and other objectives are achieved with a method for a client device, the method comprises transmitting a recommendation message, the recommendation message indicating a recommended RRM information; receiving a recommendation reply message, the recommendation reply message indicating whether the recommended RRM information is to be activated or not; and activating a RRM configuration based on the recommendation reply message.

The method according to the third aspect can be extended into implementation forms corresponding to the implementation forms of the client device according to the first aspect. Hence, an implementation form of the method comprises the feature(s) of the corresponding implementation form of the client device.

The advantages of the methods according to the third aspect are the same as those for the corresponding implementation forms of the client device according to the first aspect.

According to a fourth aspect of the invention, the above mentioned and other objectives are achieved with a method for a network access node or a coordinator client device, the method comprises receiving a recommendation message from a client device, the recommendation message indicating a recommended RRM information; transmitting a recommendation reply message to the client device, the recommendation reply message indicating whether the recommended RRM information is to be activated or not.

The method according to the fourth aspect can be extended into implementation forms corresponding to the implementation forms of the network access node or the coordinator client device according to the second aspect. Hence, an implementation form of the method comprises the feature(s) of the corresponding implementation form of the network access node or the coordinator client device.

The advantages of the methods according to the fourth aspect are the same as those for the corresponding implementation forms of the network access node or the coordinator client device according to the second aspect. The invention also relates to a computer program, characterized in program code, which when run by at least one processor causes said at least one processor to execute any method according to embodiments of the invention. Further, the invention also relates to a computer program product comprising a computer readable medium and said mentioned computer program, wherein said computer program is included in the computer readable medium, and comprises of one or more from the group: ROM (Read-Only Memory), PROM (Programmable ROM), EPROM (Erasable PROM), Flash memory, EEPROM (Electrically EPROM) and hard disk drive.

Further applications and advantages of the embodiments of the invention will be apparent from the following detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

The appended drawings are intended to clarify and explain different embodiments of the invention, in which:

- Fig. 1 shows a client device according to an embodiment of the invention;

- Fig. 2 shows a method for a client device according to an embodiment of the invention;

- Fig. 3 shows a network access node according to an embodiment of the invention;

- Fig. 4 shows a method for a network access node or a coordinator client device according to an embodiment of the invention;

- Fig. 5 shows a communication system according to an embodiment of the invention;

- Fig. 6 shows signaling for RRM recommendation exchange according to an embodiment of the invention;

- Fig. 7 shows signaling for recommendation configuration according to an embodiment of the invention;

- Fig. 8 shows signaling for RRM capability exchange according to an embodiment of the invention;

- Fig. 9 shows adaptation of CSI reporting periodicity according to an embodiment of the invention;

- Fig. 10 shows adaptation of CSI-RS frequency domain density according to an embodiment of the invention; and

- Fig. 11 shows adaptation of PM I format according to an embodiment of the invention; DETAILED DESCRIPTION

The enhancements considered for machine learning (ML)Zartificial intelligence (Al) for radio access network (RAN) in future new radio (NR) releases have some common requirements from the system-design point of view, namely:

• Flexible carrier(s): The transmission of reference signals in uplink and/or downlink would require more flexibility in defining the reference signal mapping both in time and frequency domains.

• Augmented functionalities of uplink/downlink dynamic signaling.

• Flexible radio resource measurement (RRM) parameterization.

• Interworking with other NR features and lower capability devices.

When the user equipment (UE) is collecting RRM data it can derive non-negligible insight related to interference conditions, channel conditions, channel parameters and decoding margins. The knowledge obtained by the UE from the RRM data can be exploited in adapting network operations accordingly. The UE is capable of deriving non-trivial insights based on 1) models trained at the UE side or provided by the network or 2) measurements performed at the UE side. Leveraging this capability will enable the network to be more reactive and tailor RRM operation based on the actual channel conditions. Consequently, avoiding any superfluous measurements and reference signal transmissions and/or measurements. However, in the current standard there is no possibility for the UE to recommend changes to the RRM related configurations. Without a proper framework to enable the UE to recommend changes in the configuration dynamically, these insights cannot be fully exploited. In the current standard, there is no defined method/framework for the UE to play a more active role in defining RRM configurations. This limits the degree to which RRMs can be adapted, which ultimately restricts network performance.

To fully leverage knowledge of the UE in terms of channel and interference condition insights, it would be beneficial if the UE could play a more active role in modifying RRM configurations. For examples, in 5G NR, some features use UE-initiated indications, e.g. beam failure recovery and event-triggered cross-link interference (CLI). Relying on the UE in such manner guarantees fast reactivity to beam blockage and CLI bursts, respectively. There are major advantages with UE-triggered reporting, especially in terms of link adaptation and mobility support. The inventors have identified that such a UE-centric behavior can be used to optimize RRM, in terms of feedback format, measurement resources, measurement time, etc. especially for ML/AI at physical layer-level. An objective of embodiments of the invention is therefore to provide a solution which mitigates or solves these problems related to RRM flexibility. According to embodiments of the invention a solution is provided which allows a client device to recommend changes to a RRM configuration or parts thereof to a network access node or coordinator client device and receive a recommendation reply indicating whether the recommended changes can be activated or not.

Fig. 1 shows a client device according to an embodiment of the invention. The client device may be a client device 100 or a coordinator client device 600. In the embodiment shown in Fig. 1 , the client device 100, 600 comprises a processor 102, a transceiver 104 and a memory 106. The processor 102 is coupled to the transceiver 104 and the memory 106 by communication means 108 known in the art. The client device 100, 600 further comprises an antenna or antenna array 110 coupled to the transceiver 104, which means that the client device 100, 600 is configured for wireless communications in a wireless communication system.

The processor 102 may be referred to as one or more general-purpose CPU, one or more digital signal processor (DSP), one or more application-specific integrated circuit (ASIC), one or more field programmable gate array (FPGA), one or more programmable logic device, one or more discrete gate, one or more transistor logic device, one or more discrete hardware component, one or more chipset. The memory 106 may be a read-only memory, a random access memory, or a non-volatile random access memory (NVRAM). The transceiver 104 may be a transceiver circuit, a power controller, an antenna, or an interface which communicates with other modules or devices. In embodiments, the transceiver 104 may be a separate chipset, or it is integrated with processor in one chipset. While in some implementations, the transceiver 104 the memory 106 and the processor 102 are integrated in one chipset.

That the client device 100, 600 is configured to perform certain actions can in this disclosure be understood to mean that the client device 100, 600 comprises suitable means, such as e.g. the processor 102 and the transceiver 104, configured to perform said actions.

With reference to Fig. 1 and 5, according to embodiments of the invention, the client device 100 is configured to transmit a recommendation message 510, the recommendation message 510 indicating a recommended RRM information. The client device 100 is further configured to receive a recommendation reply message 520, the recommendation reply message 520 indicating whether the recommended RRM information is to be activated or not; and activate a RRM configuration based on the recommendation reply message 520. Fig. 2 shows a flow chart of a corresponding method 200 which may be executed in a client device 100, such as the one shown in Fig. 1. The method 200 comprises transmitting 202 a recommendation message 510, the recommendation message 510 indicating a RRM information. The method 200 further comprises receiving 204 a recommendation reply message 520, the recommendation reply message 520 indicating whether the recommended RRM information is to be activated or not; and activating 206 a RRM configuration based on the recommendation reply message 520.

Fig. 3 shows a network access node 300 according to an embodiment of the invention. In the embodiment shown in Fig. 3, the network access node 300 comprises a processor 302, a transceiver 304 and a memory 306. The processor 302 is coupled to the transceiver 304 and the memory 306 by communication means 308 known in the art. The network access node 300 may be configured for both wireless and wired communications in wireless and wired communication systems, respectively. The wireless communication capability is provided with an antenna or antenna array 310 coupled to the transceiver 304, while the wired communication capability is provided with a wired communication interface 312 coupled to the transceiver 304.

The processor 302 may be referred to as one or more general-purpose CPU, one or more digital signal processor (DSP), one or more application-specific integrated circuit (ASIC), one or more field programmable gate array (FPGA), one or more programmable logic device, one or more discrete gate, one or more transistor logic device, one or more discrete hardware component, one or more chipset. The memory 306 may be a read-only memory, a random access memory, or a non-volatile random access memory (NVRAM). The transceiver 304 may be a transceiver circuit, a power controller, an antenna, or an interface which communicates with other modules or devices. In embodiments, the transceiver 304 may be a separate chipset, or it is integrated with processor in one chipset. While in some implementations, the transceiver 304 the memory 306 and the processor 302 are integrated in one chipset.

That the network access node 300 is configured to perform certain actions can in this disclosure be understood to mean that the network access node 300 comprises suitable means, such as e.g. the processor 302 and the transceiver 304, configured to perform said actions.

Both the network access node 300 according to Fig. 3 and the coordinator client device 600 according to Fig. 1 may be communicating with and exchanging RRM information with the client device 100, as shown in e.g. Fig. 5. The network access node 300 and the coordinator client device 600 may both take the network role and perform the same actions with regards to the client device 100.

With reference to Figs. 1 , 3 and 5, according to embodiments of the invention the network access node 300 or the coordinator client device 600 is configured to receive a recommendation message 510 from a client device 100, the recommendation message 510 indicating a recommended RRM information. The network access node 300 or the coordinator client device 600 is further configured to transmit a recommendation reply message 520 to the client device 100, the recommendation reply message 520 indicating whether the recommended RRM information is to be activated or not.

Fig. 4 shows a flow chart of a corresponding method 400 which may be executed in a network access node 300 or a coordinator client device 600, such as the ones shown in Fig. 3 and 1 , respectively. The method 400 comprises receiving 402 a recommendation message 510 from a client device 100, the recommendation message 510 indicating a recommended RRM information. The method 400 further comprises transmitting 404 a recommendation reply message 520 to the client device 100, the recommendation reply message 520 indicating whether the recommended RRM information is to be activated or not.

Fig. 5 shows a communication system 500 according to an embodiment of the invention. The communication system 500 comprises a network access node 300, a client device 100 and a coordinator client device 600 configured to communicate with each other over air interfaces, e.g. over an llu interface or a sidelink (SL) interface as defined according to 3GPP new radio.

A typical example is shown in Fig. 5, when it is assumed that the client device 100 is travelling at a first speed and configured by the network access node 300 to performing RRMs according to a RRM configuration suitable for the first speed. Upon detecting a deacceleration, the client device 100 recommends a change to the current RRM configuration to match the new speed. The client device 100 does this by transmitting a recommendation message 510 to the network access node 300, as shown in Fig. 5. The recommendation message 510 indicates a recommended RRM information which in this case corresponds to RRM information suitable for the new speed. In response, the network access node 300 transmits a recommendation reply message 520 to the client device 100 indicating whether the recommended RRM information is to be activated or not. Based on the received recommendation reply message 520, the client device 100 activates a RRC configuration, as will be further described below with reference to Fig. 6. With further reference to Fig. 5, the exchange of recommended RRM information according to the invention may also be performed in a sidelink scenario between the client device 100 and the coordinator client device 600. In this case, the coordinator client device 600 takes the role of the network access node 300 and hence receives the recommendation message 510 and transmits a recommendation reply message 520 in response, as indicated with dashed arrows in Fig. 5.

Fig. 6 shows signaling for RRM recommendation exchange between a client device 100 and a network access node 300 or a coordinator client device 600 according to an embodiment of the invention. In embodiments, the below described recommendation message 510 and/or the recommendation reply message 520 is a L1 or a L2 signalling message. The recommendation message 510 may e.g. be transmitted as part of uplink (UL) control information or UL MAC CE. The recommendation reply message 520 may e.g. be transmitted in downlink (DL) control information or DL MAC CE.

In step I in Fig. 6, the client device 100 transmit a recommendation message 510 to the network access node 300 or the coordinator client device 600, the recommendation message 510 indicating a recommended RRM information. That the recommended RRM information is indicated can be understood to mean that the recommended RRM information can be explicitly and/or implicitly included in the message. The recommended RRM information may e.g. be included in the recommendation message 510 as an index, a bitmap, and/or a dedicated-ID of an element. When a bitmap is used N-1 bits may be used to provide information about N number of configurations and/or parameters.

In embodiments, the recommended RRM information indicates one or more in the group comprising: a RRM configuration, a RRM model parameter, a RRM model, a RRM parameter, and a RRM format. The client device 100 may hence recommend changes to a RRM configuration and/or a RRM model either fully or partially. A model may be understood to refer to a machine learning trained or untrained model, which is described by a set of operations and parameters/coefficients, examples of model parameters may be number of clusters, in the case of unsupervised learning, number of fully connected layers, and number of possible outputs for data network name (DNN). RRM models may be used at either end of a link between the client device 100 and the network access node 300 and the client device 100 may recommend changing RRM models running at the client device 100 and/or the network access node 300 by indicating a new RRM model in a recommendation message 510 to the network access node 300. In embodiments, the recommended RRM information indicates any one of: a channel state information reporting parameter or configuration, a channel state information quantity format or parameter, a reference signal configuration or mapping parameter, or a RRM model or model parameter. The channel state information (CSI) reporting parameter or configuration may be related to e.g. reporting period, resources and triggering conditions. The CSI quantity format may be related to the format of the CSI quantity such as e.g. format of precoding matrix indicator (PMI), and the CSI quantity parameter may be related to e.g. list of CSI reporting quantities. The reference signal configuration or mapping parameter may be related to e.g. time, frequency, delay, and/or doppler domain.

The client device 100 may transmit the recommendation message 510 upon determining that a trigger requirement associated with the RRM information is fulfilled. Step I in Fig. 6 may hence be performed when client device 100 determines a trigger requirement. The client device 100 may use its analytics capabilities and stored radio resource measurements to determine that the trigger requirement associated with the RRM information is fulfilled. This allows for early detection or prediction of critical radio events such as blockage, interference bursts, increase or decrease in the estimated Doppler shifts, channel rank evolution, etc. In embodiments, the trigger requirement is a radio event associated with a timer, a counter, a measurement threshold, and/or a performance quantity. The radio event may e.g. be that a measurement, a measurement quantity or a performance metric quantity, such as e.g. recall, accuracy, precision, F1 -score, is predicted to or determined to not meet a threshold value. The threshold value may be configured by the client device 100, the network access node 300 or coordinator client device 600 and may further be indicated or client device-selected.

In step II in Fig. 6, the network access node 300 or the coordinator client device 600 receives the recommendation message 510 from the client device 100 indicating the recommended RRM information. The network access node 300 or the coordinator client device 600 hence obtains the recommended RRM information, e.g. by deriving the recommended RRM information from the indication in the recommendation message 510. Based on the obtained recommended RRM information, the network access node 300 or the coordinator client device 600 may determine whether the recommended RRM information is to be activated or not, i.e. whether the RRM information recommended by the client device 100 is to be approved or overridden. In the determination, the network access node 300 or the coordinator client device 600 may consider internal implementation and other constraints such as e.g. constraints related to multi-user operations and scheduler constraints. Furthermore, the network access node 300 or the coordinator client device 600 may determine to update current RRM information based on the recommended RRM information. In other words, if the network access node 300 or the coordinator client device 600 determines to override, i.e. not activate, the recommended RRM information, the network access node 300 or the coordinator client device 600 may instead determine to make updates to the current RRM configuration based on the recommendation from the client device 100, internal implementation and other constraints.

In step III in Fig. 6, the network access node 300 or the coordinator client device 600 transmits a recommendation reply message 520 to the client device 100, the recommendation reply message 520 indicating whether the recommended RRM information is to be activated or not. That the recommended RRM information is not to be activated may be indicated indirectly by the network access node 300 or the coordinator client device 600 indicating updated RRM information in the recommendation reply message 520. In embodiments, the indication is comprised in a downlink control information (DCI) or medium access control (MAC) control element (CE) as a recommendation acknowledgement (ACK) or negative acknowledgement (NACK), respectively.

In step IV in Fig. 6, the client device 100 receives the recommendation reply message 520 from the network access node 300 or the coordinator client device 600 and hence the indication whether the recommended RRM information is to be activated or not. Based on the recommendation reply message 520, the client device 100 activate a RRM configuration in step V in Fig. 6. If the recommendation reply message 520 indicates that the recommended RRM information is to be activated, the client device 100 may activate a new RRM configuration which is based on the recommended RRM information. If the recommendation reply message 520 indicates that the recommended RRM information is not to be activated, the client device 100 may keep the current RRM configuration or activate a predefined RRM configuration. For example, assume that the client device 100 can choose between four parameters P0, P1 , P2, P3 for a given RRM feature and is currently using parameter zero P0. If the client device 100 uses a bitmap to indicate recommended parameter, then the client device 100 may send 001 to recommend parameter three P3. The network access node 300 or coordinator client device 300 may reply to such a recommendation with bits “010” indicating that the client device 100 should switch to parameter two P2 rather than parameter three P3.

In embodiments, the recommendation reply message 520 further indicates a time offset T_Of_fset for activation of the recommended RRM information or particularly activate a RRM configuration associated with the recommended RRM information. In this case, the client device 100 may activate the recommended RRM information based on the time offset T_offset. The client device 100 may e.g. activate the recommended RRM information when a time interval corresponding to the time offset T_Offset has expired from a known time instance. In this way, the network access node 300 or the coordinator client device 600 may control when the activation of the RRM configuration by the client device 100 takes place. The time offset Toffset may be any suitable communication time units such as a slot, frame and/or symbol offset, e.g. an offset with respect to a control message between the client device 100 and the network access node 300 or the coordinator client device 600 in slots, frames, etc.

Fig. 7 shows signaling for recommendation configuration of a client device 100 by a network access node 300 or a coordinator client device 600 according to an embodiment of the invention. The recommendation configuration may be performed to configure or enable the client device 100 to provide RRM recommendations to the network access node 300 or the coordinator client device 600.

In step I in Fig. 7, the network access node 300 or the coordinator client device 600 transmits a recommendation configuration message 530 to the client device 100, the recommendation capability message 530 indicating radio resources for transmitting a recommendation message 510. The indicated radio resources may e.g. be a configured grant or a dynamic grant. The network access node 300 or the coordinator client device 600 may transmit the recommendation configuration message 530 to the client device 100, previous to receiving any recommendation message 510 from the client device 100. The recommendation configuration message 530 may be part of a RRC configuration or RRC reconfiguration procedure between the client device 100 and the network access node 300 or the coordinator client device 600.

In step II in Fig. 7, client device 100 receives the recommendation configuration message 530 indicating radio resources for transmitting the recommendation message 510. The client device 100 receives the recommendation configuration message 530 previous to transmitting the recommendation message 510 and may hence use the indicated radio resources when transmitting the recommendation message 510 to network access node 300 or the coordinator client device 600. When the indicated radio resources are a configured grant or a dynamic grant, the client device 100 transmits the recommendation message 510 according to the configured grant or the dynamic grant.

In embodiments, the recommendation configuration message 530 further indicates one or more in the group comprising: a set of valid recommended RRM information, a set of trigger requirements for transmitting the recommendation message 510, a set of radio resources in which the recommendation message 510 is transmitted, and a set of radio resources in which the recommendation reply message 520 is received. In this way, the network access node 300 or the coordinator client device 600 may control how the client device 100 handles recommended RRM information, e.g. which type of recommended RRM information to provide, when recommended RRM information is to be provided, which radio resources to use to provide the recommended RRM information, and/or which radio resources to use to obtain the reply to the recommended RRM information from the network access node 300 or the coordinator client device 600.

Fig. 8 shows signaling for RRM capability exchange between a client device 100 and a network access node 300 or a coordinator client device 600 according to an embodiment of the invention. The RRM capability exchange may be performed to allow the network access node 300 or the coordinator client device 600 to obtain information about the RRM recommendation capabilities of the client device 100.

In step I in Fig. 8, the network access node 300 or the coordinator client device 600 transmits a RRM capability enquiry message 550 to the client device 100. The RRM capability enquiry message 550 indicates an enquiry about RRM recommendation capabilities supported by the client device 100.

Upon reception of the RRM capability enquiry message 550 in step II in Fig. 8, the client device 100 transmits a recommendation capability message 540 in step III in Fig. 8. The recommendation capability message 540 indicates RRM recommendation capabilities supported by the client device 100.

In step IV in Fig. 8, the network access node 300 or the coordinator client device 600 receives the recommendation capability message 540 from the client device 100 indicating RRM recommendation capabilities supported by the client device 100. The network access node 300 or the coordinator client device 600 thereby obtains information about the recommendation capabilities of the client device 100 and may use this information when configuring the client device 100 e.g. using the above described recommendation configuration message 530.

According to embodiments of the invention the client device 100 may be a user equipment (UE) operating in a 3GPP network, such as e.g. a new radio (NR) radio access network (RAN), and the above-described procedures of the invention may be used to adapt channel state information (CSI) measurements and/or reporting for the UE. The UE may be configured to perform periodic CSI measurements and reporting, e.g. for beam management. The periodicity at which the UE needs to perform beam measurements depends on different factors including, UE velocity, its direction of movement with respect to its serving TRPs and/or secondary cell, in case of inter-cell mobility. Thus, having a constant CSI measurement and reporting periodicity may lead to under or over sampling of the channel state, depending on the defined period and UE mobility parameters. Using the invention, the UE may recommend a change in the CSI measurement and/or reporting periodicity following the detection/prediction of a variation in the channel large or small scale parameters, e.g. Doppler spread, delay spread or Doppler shift. By adapting the CSI measurement and/or reporting to the actual rate at which the channel changes, the RAN can always sample the channel at the proper rate, avoiding superfluous processing and reference signal (RS) transmission or slow reaction to the increased rate of CSI change for an accelerating UE.

Fig. 9 shows adaptation of CSI reporting periodicity based on UE recommendation according to an embodiment of the invention. With reference to Fig. 9, the UE is first configured to transmit CSI reports with an initial CSI reporting period. Upon detecting a change in the channel at a first time instance t1 , the UE transmits a recommendation message 510 to e.g. a network access node 300 in the RAN. The UE may e.g. detect a lower Doppler shift or predicting very correlated precoding matrix indicator (PMI) and based on this recommend that the CSI reporting period is decreased. The transmitted recommendation message 510 indicates the RRM information that the UE recommends, i.e. in this case an updated CSI reporting period which is longer than the initial CSI reporting period. In the embodiment shown in Fig. 9, the RAN approves/accepts the UE recommendation and transmits a recommendation reply message 520 to the UE at a second time instance t2. The recommendation reply message 520 indicates that the recommended RRM information can be activated, i.e. that the updated CSI reporting period can be used. Hence, the UE activates a CSI reporting configuration with the updated CSI reporting period and starts to transmit CSI reports with the updated CSI reporting period which is longer than the initial CSI reporting period, as shown in Fig. 9.

When the UE recommends an increase or a decrease in the CSI reporting period, the RAN considers multiple variables before approving or overriding the UE recommendation. First, enough uplink resources need to be available to be used for reporting. In case of periodic CSI, physical uplink control channel (PUCCH) reporting resource is configured by radio resource control (RRC). The RAN needs to make sure that, among other conditions:

• increasing the reporting period does not induce collision with other higher priority uplink control information, including hybrid automatic repeat request - acknowledgment (HARQ-ACK) and scheduling requests (SRs). the configured PLICCH resource has a matching period, the PLICCH resource to be used following a reporting period increase is not already in use for another report and/or user.

Fig. 10 shows adaptation of CSI-RS frequency domain density based on UE recommendation according to an embodiment of the invention. As discussed above, the rate at which the channel is sampled in time and frequency domains depends on different factors. A UE equipped with an accelerometer and gyroscope sensors can use already available information to recommend RS adaptation to the network to adapted to new channel conditions as soon as they occur. In the embodiment shown in Fig. 10, the UE recommends changes in the periodic CSI-RS frequency domain density. This recommendation can be sensible when the channel is relatively frequency flat and high frequency domain accuracy does not add meaningful information to the scheduler.

With reference to Fig. 10, the UE first performs CSI-RS measurements on downlink RSs with a first frequency domain (FD) density. Upon detecting a change in the channel at a first time instance t1 , the UE transmits a recommendation message 510 to e.g. a network access node 300 in the RAN. The recommendation message 510 indicates that the CSI-RS FD density can be decreased to a second FD density. The RAN accepts the UE recommendation and transmits a recommendation reply message 520 to the UE at a second time instance t2. The recommendation reply message 520 indicates that the recommended RRM information can be activated, i.e. that the second FD density can used. The RAN may decide to change the mapping of the transmitted downlink RSs or simply allow the UE to under-sample the transmitted downlink RSs in the frequency domain. Either way, the UE activates a CSI measurement configuration according to the second FD density and starts to perform CSI-RS measurements with the second FD density which is lower than the first FD density, as shown in Fig. 10.

If only CSI-RS measurements are to be adapted, the main consideration to be made by the RAN depends on the frequency selective scheduler implementation and the sensitivity to reduced frequency domain granularity. However, in case the transmitted downlink RSs are to be adapted, other consideration come into play when approving or overriding UE recommendations. For example, if the same periodic CSI-RS is used by multiple users, the RAN may tend to override UE recommendation so that RRMs for the other users are not affected or hindered. Otherwise, in case of UE-specific CSI-RS, more freedom is available and UE recommendation can often be approved. In 5G NR multiple PMI codebooks are supported, e.g. Type I, Type II, eType II, PS Type II, etc. Additionally, the number of PMI subbands may be the same or higher than the number of channel quality indicator (CQI) subbands, depending on the configuration. Whether a high accuracy PMI is needed or not depends mainly on whether the channel is dominated by its line-of-sight (LoS) component (frequency flat) or its multi-path components. Embodiments of the invention enables the UE to recommend a change in the PMI format and/or number of PMI subbands, i.e. enables CSI reporting configurations with flexible format. Thereby, RRC configuration may be compressed and PMI feedback can match the channel conditions better, before quantization and approximation via PMIs. Adaptation of the PMI format based on UE recommendation can further free part of the uplink reporting resources which can be used in order to guarantee less uplink channel dropping due to intra-UE multiplexing or to convey additional control information/data.

Fig. 11 shows adaptation of PMI format based on UE recommendation according to an embodiment of the invention. With reference to Fig. 11 , the UE is first configured to transmit CSI reports including a Type II PMI. Upon detecting a change in the channel at a first time instance t1 , the UE transmits a recommendation message 510 to e.g. a network access node 300 in the RAN. The UE may e.g. detect low frequency selectivity, i.e. a LoS dominated link, and based on this recommend a new PMI format such as Type I PMI. The transmitted recommendation message 510 indicates the RRM information that the UE recommends, i.e. in this case the new format Type I PMI. In the embodiment shown in Fig. 11 , the RAN approves the UE recommendation and transmits a recommendation reply message 520 to the UE at a second time instance t2. The recommendation reply message 520 indicates that the recommended RRM information can be activated, i.e. that the Type I PMI format can be used. Hence, the UE activates a CSI reporting configuration with PMI reporting according to Type I and starts to transmit CSI reports including a Type I PMI, as shown in Fig. 11 .

When approving or overriding UE recommendation related to PMI format, the network considers the resulting overhead. For example, Type I PMI can be transmitted over PUCCH or PUSCH, thanks to its limited overhead. However, Type II PMI can only be transmitted over PUSCH as they require more reporting resources. The network hence needs to consider whether there is enough room to switch between Type I PMI and Type II PMI and/or increase the number of PMI subbands without causing CSI omissions due to insufficient reporting resource.

The client device 100 and the coordinator client device 600 herein may be denoted as a user device, a user equipment (UE), a mobile station, a transmission and reception point (TRP), a road side unit (RSU), a an internet of things (loT) device, a sensor device, a wireless terminal and/or a mobile terminal, is enabled to communicate wirelessly in a wireless communication system, sometimes also referred to as a cellular radio system. The UEs may further be referred to as mobile telephones, cellular telephones, computer tablets or laptops with wireless capability. The UEs in this context may be, for example, portable, pocket-storable, hand-held, computer-comprised, or vehicle-mounted mobile devices, enabled to communicate voice and/or data, via the radio access network, with another entity, such as another receiver or a server. The UE can be a Station (STA), which is any device that contains an IEEE 802.11- conformant Media Access Control (MAC) and Physical Layer (PHY) interface to the Wireless Medium (WM). The UE may also be configured for communication in 3GPP related LTE and LTE-Advanced, in WiMAX and its evolution, and in fifth generation wireless technologies, such as New Radio.

The network access node 300 herein may be denoted as a radio network access node, an access network access node, an access point, or a base station, e.g. a Radio Base Station (RBS), which in some networks may be referred to as transmitter, “gNB”, “gNodeB”, “eNB”, “eNodeB”, “NodeB” or “B node”, depending on the technology and terminology used. The radio network access nodes may be of different classes such as e.g. macro eNodeB, home eNodeB or pico base station, based on transmission power and thereby also cell size. The radio network access node can be a Station (STA), which is any device that contains an IEEE 802.11 -conformant Media Access Control and Physical Layer interface to the Wireless Medium. The radio network access node may also be a base station (BS) corresponding to the fifth generation (5G) wireless systems.

Furthermore, any method according to embodiments of the invention may be implemented in a computer program, having code means, which when run by processing means causes the processing means to execute the steps of the method. The computer program is included in a computer readable medium of a computer program product. The computer readable medium may comprise essentially any memory, such as a ROM (Read-Only Memory), a PROM (Programmable Read-Only Memory), an EPROM (Erasable PROM), a Flash memory, an EEPROM (Electrically Erasable PROM), or a hard disk drive.

Moreover, it is realized by the skilled person that embodiments of the client device 100, the network access node 300 and the coordinator client device 600 comprise the necessary communication capabilities in the form of e.g., functions, means, units, elements, etc., for performing the solution. Examples of other such means, units, elements and functions are: processors, memory, buffers, control logic, encoders, decoders, rate matchers, de-rate matchers, mapping units, multipliers, decision units, selecting units, switches, interleavers, deinterleavers, modulators, demodulators, inputs, outputs, antennas, amplifiers, receiver units, transmitter units, DSPs, MSDs, TCM encoder, TCM decoder, power supply units, power feeders, communication interfaces, communication protocols, etc. which are suitably arranged together for performing the solution.

Especially, the processor(s) of client device 100, the network access node 300 and the coordinator client device 600 may comprise, e.g., one or more instances of a Central Processing Unit (CPU), a processing unit, a processing circuit, a processor, an Application Specific Integrated Circuit (ASIC), a microprocessor, or other processing logic that may interpret and execute instructions. The expression “processor” may thus represent a processing circuitry comprising a plurality of processing circuits, such as, e.g., any, some or all of the ones mentioned above. The processing circuitry may further perform data processing functions for inputting, outputting, and processing of data comprising data buffering and device control functions, such as call processing control, user interface control, or the like.

Finally, it should be understood that the invention is not limited to the embodiments described above, but also relates to and incorporates all embodiments within the scope of the appended independent claims.

Claims

1. A client device (100) for a communication system (500), the client device (100) being configured to transmit a recommendation message (510), the recommendation message (510) indicating a recommended radio resource measurement, RRM, information; receive a recommendation reply message (520), the recommendation reply message (520) indicating whether the recommended RRM information is to be activated or not; and activate a RRM configuration based on the recommendation reply message (520).

2. The client device (100) according to claim 1 , further configured to transmit the recommendation message (510) upon determining that a trigger requirement associated with the RRM information is fulfilled.

3. The client device (100) according to claim 2, wherein the trigger requirement is a radio event associated with a timer, a counter, a measurement threshold, and/or a performance quantity.

4. The client device (100) according to any one of the preceding claims, further configured to receive a recommendation configuration message (530) previous to transmitting the recommendation message (510), the recommendation configuration message (530) indicating radio resources for transmitting the recommendation message (510).

5. The client device (100) according to claim 4, wherein the recommendation configuration message (530) further indicates one or more in the group comprising: a set of valid recommended RRM information, a set of trigger requirements for transmitting the recommendation message (510), a set of radio resources in which the recommendation message (510) is transmitted, and a set of radio resources in which the recommendation reply message (520) is received.

6. The client device (100) according to any one of the preceding claims, further configured to transmit a recommendation capability message (540), the recommendation capability message (540) indicating RRM recommendation capabilities supported by the client device (100) upon reception of a RRM capability enquiry message (550).

7. The client device (100) according to any one of the preceding claims, wherein the recommendation reply message (520) further indicates a time offset (T_Of_fset) for activation of

25 the recommended RRM information, and wherein the client device (100) further is configured to activate the recommended RRM information based on the time offset (T_0/y_set).

8. The client device (100) according to any one of the preceding claims, wherein the recommended RRM information indicates one or more in the group comprising: a RRM configuration, a RRM model parameter, a RRM model, a RRM parameter, and a RRM format.

9. The client device (100) according to claim 8, wherein the recommended RRM information indicates any one of: a channel state information reporting parameter or configuration, a channel state information quantity format or parameter, a reference signal configuration or mapping parameter, or a RRM model or model parameter.

10. The client device (100) according to any one of the preceding claims, further configured to transmit the recommendation message (510) to a network access node (300) or a coordinator client device (600); and receive the recommendation reply message (520) from the network access node (300) or the coordinator client device (600).

11. The client device (100) according to any one of the preceding claims, wherein the recommendation message (510) and/or the recommendation reply message (520) is a L1 or a L2 signalling message.

12. A network access node (300) or a coordinator client device (600) for a communication system (500), the network access node (300) or the coordinator client device (600) being configured to receive a recommendation message (510) from a client device (100), the recommendation message (510) indicating a recommended RRM information; transmit a recommendation reply message (520) to the client device (100), the recommendation reply message (520) indicating whether the recommended RRM information is to be activated or not.

13. The network access node (300) or the coordinator client device (600) according to claim

12, further configured to transmit a recommendation configuration message (530) to the client device (100) previous to receiving the recommendation message (510), the recommendation capability message (530) indicating radio resources for transmitting the recommendation message (510).

14. The network access node (300) or the coordinator client device (600) according to claim

13, wherein the recommendation configuration message (530) further indicates one or more in the group comprising: a set of valid recommended RRM information, a set of trigger requirements for transmitting the recommendation message (510), a set of radio resources in which the recommendation message (510) is transmitted, and a set of radio resources in which the recommendation reply message (520) is received.

15. The network access node (300) or the coordinator client device (600) according to any one of claims 12 to 14, further configured to transmit a RRM capability enquiry message (550) to the client device (100), RRM capability enquiry message (550) indicating an enquiry about RRM recommendation capabilities supported by the client device (100); and receive a recommendation capability message (540) from the client device (100), the recommendation capability message (540) indicating RRM recommendation capabilities supported by the client device (100).

16. The network access node (300) or the coordinator client device (600) according to any one of claims 12 to 15, wherein the recommendation reply message (520) further indicates a time offset (T_Of_fset) for activation of the recommendation RRM information.

17. The network access node (300) or the coordinator client device (600) according to any one of claims 12 to 16, wherein the recommended RRM information indicates one or more in the group comprising: a RRM configuration, a RRM model parameter, a RRM model, a RRM parameter, and a RRM format.

18. The network access node (300) or the coordinator client device (600) according to claim

17, wherein the recommended RRM information indicates any one of: a channel state information reporting parameter or configuration, a channel state information quantity format or parameter, a reference signal configuration or mapping parameter, or a RRM model or model parameter.

19. The network access node (300) or the coordinator client device (600) according to any one of claims 12 to 18, wherein the recommendation message (510) and/or the recommendation reply message (520) is a L1 or a L2 signalling message.

20. A method (200) for a client device (100) in a communication network (500), the method (200) comprising transmitting (202) a recommendation message (510), the recommendation message (510) indicating a recommended radio resource measurement, RRM, information; receiving (204) a recommendation reply message (520), the recommendation reply message (520) indicating whether the recommended RRM information is to be activated or not; and activating (206) a RRM configuration based on the recommendation reply message (520).

21. A method (400) for a network access node (300) or a coordinator client device (600) in a communication network (500), the method (400) comprising receiving (402) a recommendation message (510) from a client device (100), the recommendation message (510) indicating a recommended RRM information; transmitting (404) a recommendation reply message (520) to the client device (100), the recommendation reply message (520) indicating whether the recommended RRM information is to be activated or not.

22. A computer program with a program code for performing a method according to any one of claim 20 or 21 when the computer program runs on a computer.

28