Dormant cells

Abstract

Examples of the disclosure relate to managing measurements for dormant cells and transitions between dormant and active or inactive states. In examples a UE receives from a network node an indication that a first cell is in a dormant state and information for enabling measurements associated with the first cell while the first cell is in the dormant state. The UE then performs measurements for the first cell while the first cell is in the dormant state in accordance with the received information.

Description

[0001] TITLE

[0002] Dormant Cells

[0003] TECHNOLOGICAL FIELD

[0004] Examples of the disclosure relate to dormant cells. Some relate to managing measurements for dormant cells and transitions between dormant and active or inactive states.

[0005] BACKGROUND

[0006] In cellular networks, an active state for a cell can be used for communication and a deactivated state for a cell can be used to save UE power when the cell is not immediately needed for communication. A dormant state can be used for cells as an intermediate state between an active state and an inactive state.

[0007] BRIEF SUMMARY

[0008] According to various, but not necessarily all, examples of the disclosure there is provided a user equipment (UE) comprising: at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the UE at least to perform: receiving from a network node an indication that a first cell is in a dormant state and information for enabling measurements associated with the first cell while the first cell is in the dormant state; and performing measurements for the first cell while the first cell is in the dormant state in accordance with the received information.

[0009] The bandwidth used for measurements for the first cell while the first cell is in the dormant state may be at least one of: different to the bandwidth used for measurements for the first cell while the first cell is in an active state; and narrower than the bandwidth used for measurements for the first cell while the first cell is in an active state. The measurements for the first cell while the first cell is in the dormant state may be less frequently than the measurements for the first cell while the first cell is in an active state.

[0010] The processor and at least one memory may also be arranged to cause the UE to perform changing the state of the first cell from a dormant state to an active state in response to a trigger condition.

[0011] Changing the state of the first cell from a dormant state to an active state may comprise applying results from measurements made while the first cell is in the dormant state to start monitoring for messages from the first cell.

[0012] Changing the state of the first cell from a dormant state to an active state may comprise reporting measurements for a wider bandwidth.

[0013] The information for enabling measurements while the first cell is in a dormant state may comprise at least one of: a first resource to be used for the measurements; a bandwidth to be used for the measurements; intervals between measurements; intervals between measurement reports.

[0014] The bandwidth to be used for performing measurements while the first cell is in a dormant state may be one of; set as a fixed value; a configured value.

[0015] The first resource may be based on a configuration of the first cell when the first cell is in an active state.

[0016] The first resource may be configured for the dormant state of the first cell.

[0017] The indication that the first cell is in a dormant state and information for enabling measurements associated with the first cell may be received in at least one of: a radio resource control message; a medium access control element; layer 1 or layer 2 signaling. The indication that the first cell is in a dormant state may be received with activation or deactivation information for one or more cells.

[0018] The indication that the first cell is in a dormant state may be received as independent signalling.

[0019] The trigger condition for changing the state of the of the first cell from a dormant state to an active state may comprises at least one of: an indication comprised in signalling to the UE; being scheduled a block of data that exceeds threshold conditions for a second cell; being scheduled a block of data on the first cell via a scheduling message on another cell; receiving a request of measurement reporting for the first cell when the first cell is in a dormant state.

[0020] The processor and at least one memory may also be arranged to cause the UE to perform receiving an indication that the first cell has been switched from the dormant state to a deactivated state and stopping the measurements for the first cell.

[0021] According to various, but not necessarily all, examples of the disclosure there may be provided a method comprising; receiving from a network node an indication that a first cell is in a dormant state and information for enabling measurements associated with the first cell while the first cell is in the dormant state; and performing measurements for the first cell while the first cell is in the dormant state in accordance with the received information.

[0022] According to various, but not necessarily all, examples of the disclosure there may be provided a network node comprising: at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the network node at least to perform: sending to a user equipment (UE) an indication that a first cell is in a dormant state and information for enabling measurements associated with the first cell while in the dormant state where the measurements are at least one of: performed on bandwidth narrower than the bandwidth used for measurements when the first cell is in an active state; performed on bandwidth different than the bandwidth used for measurements when the first cell is in an active state; reported less frequently than when the first cell is in an active state.

[0023] The processor and at least one memory may also be arranged to cause the network node to perform enabling the first cell to switch from the dormant state to an active state by sending to the UE an indication that the first cell is switching from the dormant state to the active state.

[0024] The processor and at least one memory may also be arranged to cause the network node to perform enabling the first cell to switch from the active state to the dormant sate by sending to the UE an indication that the first cell is switching from the active state to the dormant state.

[0025] According to various, but not necessarily all, examples of the disclosure there may be provided a method comprising: sending to a user equipment (UE) an indication that a first cell is in a dormant state and information for enabling measurements associated with the first cell while in the dormant state where the measurements are at least one of: performed on bandwidth narrower than the bandwidth used for measurements when the first cell is in an active state; performed on bandwidth different than the bandwidth used for measurements when the first cell is in an active state; reported less frequently than when the first cell is in an active state.

[0026] According to various, but not necessarily all, embodiments there is provided an apparatus comprising: at least one processor; and at least one memory including computer program code; the at least one memory storing instructions that, when executed by the at least one processor, cause the apparatus to perform at least a part of one or more methods described herein.

[0027] According to various, but not necessarily all, embodiments there is provided an apparatus comprising means for performing at least part of one or more methods described herein. The description of a function and / or action should additionally be considered to also disclose any means suitable for performing that function and / or action. Functions and / or actions described herein can be performed in any suitable way using any suitable method.

[0028] According to various, but not necessarily all, embodiments there is provided examples as claimed in the appended claims.

[0029] While the above examples of the disclosure and optional features are described separately, it is to be understood that their provision in all possible combinations and permutations is contained within the disclosure. It is to be understood that various examples of the disclosure can comprise any or all the features described in respect of other examples of the disclosure, and vice versa. Also, it is to be appreciated that any one or more or all the features, in any combination, may be implemented by / comprised in / performable by an apparatus, a method, and / or computer program instructions as desired, and as appropriate. The description of a function should additionally be considered to also disclose any means suitable for performing that function

[0030] BRIEF DESCRIPTION

[0031] Some examples will now be described with reference to the accompanying drawings in which:

[0032] FIG. 1 shows an example communication network;

[0033] FIGS. 2A and 2B show example methods;

[0034] FIG. 3 shows an example method;

[0035] FIG. 4 shows an example method for a UE;

[0036] FIGS. 5A and 5B shows example cell states and bandwidths;

[0037] FIG. 6 shows transitions to an active state; and

[0038] FIG. 7 shows an example controller. The figures are not necessarily to scale. Certain features and views of the figures can be shown schematically or exaggerated in scale in the interest of clarity and conciseness. For example, the dimensions of some elements in the figures can be exaggerated relative to other elements to aid explication. Corresponding reference numerals are used in the figures to designate corresponding features. For clarity, all reference numerals are not necessarily displayed in all figures.

[0039] DEFINITIONS

[0040] CSI Channel State Information

[0041] CSI-RS Channel State Information-Reference Signal

[0042] DCI Downlink Control Information

[0043] MAC CE Medium Access Control-Control Element

[0044] PDCCH Physical Downlink Control Channel

[0045] PRB Physical Resource Block

[0046] RRC Radio Resource Control

[0047] SSB Synchornization Signal Block

[0048] TRS Tracking Reference Signal

[0049] UE User Equipment

[0050] DETAILED DESCRIPTION

[0051] Fig. 1 illustrates an example of a communication network 100 to which examples of the disclosure can be applied. The communication network 100 is a cellular communication network. The communication network comprises network nodes 102. The network nodes 102 provide one or more cells 104. The cells 104 may define a coverage area or a service area of the corresponding network node 102.

[0052] The network nodes 102 can provide one or more user equipments (UE) 106 with wireless access to the communication network. The wireless access may comprise downlink (DL) communication from the network node 102 to the UE 106 and uplink (UL) communication from the UE 106 to the network node 102. Examples of uplink channels comprise physical uplink control channel (PUCCH) for transmitting control information and physical uplink shared channel (PUSCH) for transmitting data towards the network nodes 102. Examples of downlink channels comprise physical downlink control channel (PDCCH) for transmitting control information and physical downlink shared channel (PDSCH) for transmitting data towards the UE 106.

[0053] There may be a plurality of UEs 106 in the network 100. Respective UEs 106 can be served by the same or by different network nodes 102.

[0054] If the communication network 100 comprises multiple network nodes 102 the network nodes 102 can be connected to each other via an interface. LTE specifications refer to such an interface as an X2 interface. An interface between an LTE node and a 5G node, or between two 5G nodes can be called an Xn interface.

[0055] The network nodes 102 can be further connected via another interface to a core network 108 of the communication network 100. The LTE specifications specify the core network as an evolved packet core (EPC), and the core network may comprise such as a mobility management entity (MME) and a gateway node. The MME may handle mobility of terminal devices in a tracking area encompassing a plurality of cells and handle signalling connections between the terminal devices and the core network. The gateway node may handle data routing in the core network and to / from the terminal devices such as the UEs 106. The 5G specifications specify the core network as a 5G core (5GC). The 5G core may comprise e.g. an access and mobility management function (AMF) and a user plane function / gateway (UPF) and other functions. The AMF may handle termination of non- access stratum (NAS) signalling, NAS ciphering & integrity protection, registration management, connection management, mobility management, access authentication and authorization, security context management. The UPF node may support packet routing and forwarding, packet inspection and quality of service (QoS) handling, for example.

[0056] A cell 104 can be in different states. For example, if a UE 106 is in dual connectivity mode the UE 106 can be connected to multiple cells 104 at the same time. A cell 106 could be in an active state, a deactivated state, or a dormant state. In an active state a cell can be used for communication and in a deactivated state a cell is not used for communication. No measurements are made for a cell in the deactivated state. A dormant state can be used for cells as an intermediate state between an active state and an inactive state. Some measurements can be made for the cell when it is in a dormant state. The measurements for the dormant state are reduced compared to the measurements made when the cell is in an active state. In some examples a UE 106 can be listening on multiple cells simultaneously.

[0057] Figs. 2A and 2B show example methods that can be implemented in examples of the disclosure. These methods can enable a UE 106 to perform measurements on a first cell while the first cell is in a dormant state.

[0058] The method of Fig. 2A can be performed by a UE 106 and the method of Fig. 2B could be performed by a corresponding network node 102. A UE 106 that performs the method of Fig. 2A can be configured for communication with a network node 102 that performs the method of Fig. 2B.

[0059] In the example, of Fig. 2A, at block 200, the UE 106 receives an indication that a first cell is in a dormant state. The UE 106 also receives information for enabling measurements associated with the first cell while the first cell is in the dormant state. The indication and information are received from a network node 102 such as a network node 102 that performs the method of Fig. 2B. The network node 102 that provides an indication that a first cell is in a dormant state can also provide a second cell for maintaining communication with the UE 106.

[0060] At block 202, the method comprises performing measurements for the first cell. The measurements are performed by the UE 106 while the first cell is in the dormant state. The measurements are performed in accordance with the information received from the network node 102.

[0061] The measurements that are performed by the UE 106 while the first cell is in the dormant state performed so that they use less energy and / or fewer resources for the UE 106 compared to measurements that would be performed by the UE 106 while the first cell is in an active state. For example, the bandwidth used for measurements for the first cell while the first cell is in the dormant state can be narrower than, or different to, the bandwidth used for measurements for the first cell while the first cell is in an active state. In some examples, the measurements for the first cell while the first cell is in the dormant state can be performed less frequently compared to the measurements for the first cell while the first cell is in an active state. The information for enabling measurements while the first cell is in a dormant state that is received from the network node 102 can comprise any information that enables a UE 106 to perform and report the measurements on the first cell. In some examples the information can comprise a first resource to be used for the measurements. This indicates the resource at which the measurements are to be started. The resource can be a channel state information-reference signal (CSI-RS) resource or any other suitable type of resource. The first resource can be based on a configuration of the first cell when the first cell is in an active state. For example the first resource could be an offset from the first resource used for the first cell in the active state or could be obtained by truncating the resources used for the first cell in the active state. In other examples the first resource could be configured for the dormant state of the first cell.

[0062] In some examples the information can comprise a bandwidth to be used for the measurements. This bandwidth can be set as a fixed value or can be a configured value.

[0063] In some examples the information can comprise an indication of intervals between measurements and / or intervals between measurement reports. This indicates how often the UE 106 needs to perform the measurements and how often the UE 106 needs to provide the measurement reports.

[0064] The indication that the first cell is in a dormant state and information for enabling measurements associated with the first cell can be received using any suitable signaling. For instance, this could be received using a radio resource control (RRC) message, a medium access control element (MAC CE), layer 1 or layer 2 signaling, or any other suitable signaling.

[0065] In some examples the indication that the first cell is in a dormant state can be received with activation or deactivation information for one or more cells. In some examples the indication that the first cell is in a dormant state can be received as independent signalling. If the indication is received as independent signaling it is received without the activation or deactivation information for one or more other cells. In such examples activation or deactivation information for one or more other cells could be provided in MAC CE or any other suitable signalling.

[0066] In some examples the method can comprise additional blocks that are not shown in Fig. 2A. For example the method could comprise changing the state of the first cell from a dormant state to an active state in response to a trigger condition. This can enable the first cell to be activated so that it can be used for communication.

[0067] To change the state of the first cell from a dormant state to an active state the UE 106 can apply results from measurements made while the first cell is in the dormant state to start monitoring for messages from the first cell. For example, the measurement results could be used to monitor the PDCCH or any other suitable channel.

[0068] When the UE 106 changes the state of the first cell from a dormant state to an active state the UE 106 can start to use different information for the measurements. This can enable the UE 106 to report measurement for a wider bandwidth.

[0069] The trigger condition for changing the state of the of the first cell from a dormant state to an active state can comprise any suitable condition or event. The trigger condition could be related to network traffic or could be a specific signal from a network node 102. In some examples the trigger condition could be comprised in signalling to the UE 106. This signalling could be MAC CE or downlink control information (DCI) or any other suitable type of information.

[0070] In some examples the trigger condition could comprise the UE 106 being scheduled a block of data that exceeds threshold conditions for a second cell. The second cell can be cell that is in an active state. The second cell can be a cell for which the UE is monitoring the PDCCH. The threshold conditions could be that the size of the block of data meets or exceeds a configured threshold for a given number of slots. In some examples, the trigger condition could be that the resource allocation of the block of data meets or exceeds a configured threshold for a given number of slots.

[0071] In some examples the trigger condition could be that the UE 106 is scheduled a block of data on the first cell. The scheduling of this data could be via a scheduling message on another cell. The another cell can be an active cell.

[0072] In some examples the trigger condition could be that the UE 106 receives a request of measurement reporting for the first cell when the first cell is in a dormant state. This could be aperiodic CSI reporting or any other suitable type of reporting. In some examples the method could comprise changing the state of the first cell from a dormant state to a deactivated state. When the first cell is in the deactivated state the UE 106 stops the measurements for the first cell. The UE 106 can change the state of the first cell from a dormant state to a deactivated state in response to any suitable trigger condition. For example, the UE 106 could receive a signal from a network node 102 indicating that the first cell is to be changed to a deactivated state. In other examples the first cell could be switched to the deactivated state in response to network traffic conditions. For example, if the network traffic is low then the first cell could be deactivated.

[0073] Fig. 2B shows a method that can be implemented by a network node 102. This can be a network node 102 that is communicating with a UE 106 that performs the method of Fig. 2A. The network node 102 could be an access node such as a gNB in a 5G network, or any other suitable type of network node 102.

[0074] At block 210, the method comprises sending to a user equipment 106 an indication that a first cell is in a dormant state and information for enabling measurements associated with the first cell while in the dormant state. The measurements can be performed on a bandwidth narrower than, and / or different to, the bandwidth used for measurements when the first cell is in an active state. The measurements can be reported less frequently than when the first cell is in an active state.

[0075] In some examples the method performed by the network node 102 can also comprise additional blocks that are not shown in Fig. 2B. For example, the network node 102 can enable the first cell to switch from the dormant state to an active state by sending to the UE 106 an indication that the first cell is switching from the dormant state to the active state. Similarly the network node 102 can enable the first cell to switch from the active state to the dormant sate by sending to the UE an indication that the first cell is switching from the active state to the dormant state.

[0076] Fig. 3 shows another example method. This method could be implemented by a UE 106 and one or more cells 104. The cells 104 are provided by one or more network nodes 102.

[0077] At block 300 cell configuration is performed. The first cell 104_1 is configured in a dormant state. A second cell 104_2 is configured in an active state while the first cell 104_1 is in the dormant state. The UE 106 can communicate with the second cell 104_2 while the first cell 104_1 is in the dormant state.

[0078] At block 302 an RRC-reconfiguration signal is sent from the second cell 104_2 to the UE 106. This signal can comprise an indication that the first cell 104_1 is in a dormant state and also information for enabling measurements associated with the first cell 104_1 while the first cell 104_1 is in the dormant state.

[0079] The information for enabling measurements could comprise an indication of the bandwidth to be used for the measurements. The bandwidth can be narrower than, or different to, the bandwidth that would be used for measurements of the first cell 104_1 in the active state.

[0080] The information for enabling measurements could comprise an indication of the resources to be used for the measurements. The resources could be CSI-RS resources or any other suitable type of resources. In some examples the UE 106 can be configured with a specific CSI-RS configuration for the dormant state of the first cell 104_1. The specific CSI-RS configuration for the dormant state can be independent of any CSI-RS configurations for an active state of the first cell 104_1.

[0081] In other examples the CSI-RS configuration for the dormant state of the first cell 104_1 can be based on, or derived from, the CSI-RS configuration provided for the active state of the first cell 104_1. For example, the CSI-RS configuration for the dormant state of the first cell 104_1 can be obtained by adapting the CSI-RS configuration provided for the active state of the first cell 104_1 . The adaptation of the configuration provided for the active state could comprise offsetting a first resource, truncating a bandwidth, or any other suitable adaptation.

[0082] In some examples the second cell 104_2 can indicate a frequency location together with the measurement bandwidth. For example, if synchronization signal block (SSB) is not used on the first cell 104_1 , the CSI-RS could start anywhere within the configured bandwidth.

[0083] In some examples the second cell 104_2 indicates the start of the CSI-RS resources for the first cell 104_1 in the active state and the UE 106 uses this information to determine the start of the CSI-RS resources for the first cell 104_1 in the dormant state. For example, the UE 106 can apply an offset to start of the CSI-RS resources for the first cell 104_1 in the active state so as to determine the start of the CSI-RS resources for the first cell 104_1 in the dormant state. The offset could be N sequences as shown in equation 1. N is chosen such that the SSB is contained within the measurement bandwidth. dormant_state_csirs_startPRB = active_state_csirs_startPRB + N*seq_len_csirs (1)

[0084] In examples where the bandwidth is truncated the second cell 104_2 can indicate the bandwidth for the first cell 104_1 in the active state. The UE 106 can truncate the bandwidth for the first cell 104_1 in the active state from one side or from both sides so as to reach the bandwidth for measurements of the first cell 104_1 in the dormant state. This option can be used for cases with cells without SSB.

[0085] In some examples the UE 106 can determine the exact CSI-RS resource for measurement (as long as SSB is contained).

[0086] At block 304, the UE 106 responds to the RRC-reconfiguration signal by sending an RRC-Reconfiguration complete signal to the second cell 104_2.

[0087] After the cells 104 have been configured the UE 106 will continue to perform measurements and monitor PDCCH for the second cell 104_2 and any other cells that are in an active state.

[0088] For the first cell 104_1 , which is in the dormant state, the UE 106 will, at block 306, start measurement reference signals from the first cell 104_1. These measurements are reduced measurements compared to the measurements that would be performed for the first cell 104_1 in an active state. The measurements are performed in accordance with the information received from the second cell 104_2.

[0089] In some example embodiments, when the first cell 104_1 is in the dormant state the UE 106 does not monitor the PDCCH for the first cell 104_1 .

[0090] The first cell 104_1 can be switched from the dormant state to an active state at any suitable time. For example, if network traffic increases, then the first cell 104_1 can be switched from the dormant state to an active state to enable the UE 106 to exchange data on the first cell 104_1.

[0091] Block 308 shows a first cell 104_1 being switched from a dormant state to an active state.

[0092] At block 310 an indication is sent from the second cell 104_2 to the UE 106. This indicates that the first cell 104_1 is to be switched from the dormant state to an active state. The indication can be sent using any suitable signalling such as MAC CE or DCI. The indication can comprise activation or deactivation information for one or more other carriers or cells. In other examples the indication can be specific to the first cell 104_1.

[0093] The UE 106 sends an acknowledgement to the indication at block 312. The acknowledgment can be a hybrid automatic repeat request (HARQ) or any other suitable acknowledgement to acknowledge the successful reception the indication.

[0094] At block 314, the UE 106, starts monitoring PDCCH on the first cell 104_1. The UE 106 can apply the results of measurements made while the first cell 104_1 was in the dormant state to enable monitoring of the PDCCH. This can enable the UE 106 to quickly change the state of the first cell 104_1 from dormant state to active state because the results of the measurements are already available.

[0095] When the first cell 104_1 is in the active state the UE 106 also changes the measurements and measurement reporting to use the configuration for the first cell 104_1 in the active state. For example, the UE 106 will now use a wider bandwidth for the measurements and perform measurement reports more frequently.

[0096] In the example of Fig. 3 the UE 106 switches the first cell 104_1 from a dormant state to an active state in response to an indication from the second cell 104_2. In other examples other trigger conditions could be used to cause the switch. For example, the UE 106 could be scheduled a block of data that exceeds some predetermined thresholds. As an example, the trigger condition could be that the size of the block of data could be determined to meet or exceed a configured threshold and / or the resource allocation of the block of data could meet or exceed a configured threshold for at least K out of M consecutive downlink slots, where K is less than or equal to M. Both K and M may be configurable parameters. Other trigger conditions could be used in other examples, such as, the UE 106 being scheduled a block of data on the first cell 104_1 while it is in the dormant state. This scheduling can occur via a scheduling message from the second cell 104_2 or via any other active cell. In some examples the trigger condition could comprise a request of an aperiodic CSI reporting on the first cell 104_1 while it is in the dormant state, or any other suitable trigger condition.

[0097] Block 316 shows a first cell 104_1 being switched from an active state to a dormant state. This could occur if the network traffic decreases or for any other suitable reason.

[0098] At block 318 an indication is sent from the second cell 104_2 to the UE 106. This indicates that the first cell 104_1 is to be switched from the active state to a dormant state. The indication can be sent using any suitable signalling such as MAC CE or DCI. The indication can comprise activation or deactivation information for one or more other carriers or cells. In other examples the indication can be specific to the first cell 104_1.

[0099] The UE 106 sends an acknowledgement to the indication at block 320. The acknowledgment can be a hybrid automatic repeat request (HARQ) or any other suitable acknowledgement to acknowledge the successful reception the indication.

[0100] At block 322, the UE 106, stops monitoring PDCCH on the first cell 104_1. The UE 106 also changes the procedure for performing and reporting measurements on the first cell 104_1 so that it now uses the procedure for the first cell 104_1 in a dormant state. This can reduce the frequency and / or bandwidth of measurements compared to those that were performed when the first cell 104_1 was in the active state. Also, the measurement report can be sent less frequently for example.

[0101] Fig. 4 shows an example method that can be performed by a UE 106 in examples of the disclosure. This could be a UE 106 that implements the methods of Figs. 2A, Fig. 3 or any other suitable methods.

[0102] At block 400 the UE 106 receives an RRC reconfiguration. This can comprise an indication of the state of the first cell 104_1 . The RRC reconfiguration can be received from a network node 102. This can be a network node 102 that provides one or more active cells for the UE 106. The RRC reconfiguration can also comprise information for enabling measurements associated with the first cell 104_1 while the first cell 104_1 is in a dormant state. The RRC reconfiguration can also comprise any other suitable information, for example, measurement bandwidth, reference signals for measurement, reporting configuration and so on. Other types of signalling, such as L1 / L2 signalling could be used in other examples.

[0103] At block 402 the UE 106 determines if the first cell 104_1 is in the dormant state. The UE 106 can use the indication in the RRC reconfiguration to determine if the first cell 104_1 is in the dormant state.

[0104] If it is determined that the first cell 104_1 is not in a dormant state then the method proceeds to block 404. If the first cell 104_1 is not in a dormant state then it can be in either an active state or a deactivated state.

[0105] At block 404 the UE 106 performs operations for the first cell 104_1 in either the active state or the deactivated state. If the first cell 104_1 is in the active state then the UE 106 performs measurements and monitors the PDCCH. If the first cell 104_1 is in the deactivated state then the UE 106 does not perform channel measurements or monitor the PDCCH.

[0106] If, at block 402, it is determined that the first cell 104_1 is in a dormant state then the method proceeds to block 406. At block 406 the UE 106 determines bandwidth has been explicitly configured. The dormant bandwidth is the bandwidth that is used for performing measurements for the first cell 104_1 while the first cell 104_1 is in the dormant state. This bandwidth can be narrower than, or different to, the bandwidth that is used for performing measurements for the first cell 104_1 while the first cell 104_1 is in the active state.

[0107] If the dormant bandwidth is not explicitly configured then the method proceeds to block 408. In these cases the dormant bandwidth is a standard value. The UE 106 can determine the standard value and the method proceeds to block 410.

[0108] If the dormant bandwidth is explicitly configured then the UE 106 can retrieve the configuration for the bandwidth and the method proceeds to block 410. At block 410 the UE determines if dormant measurement resources have been configured for the first cell 104_1 . The dormant measurement resources can comprise CSI-RS resources or any other suitable type of resources. If the dormant measurement resources have not been configured then the method proceeds to block 412.

[0109] At block 412 it is determined whether the frequency start is configured for the measurements on the first cell 104_1 in the dormant state. If the frequency start is configured then at block 418 the configured frequency start is used. If the frequency start is not configured then at block 420 the frequency start is determined. The UE 106 can determine the frequency start based on the configuration for the active state of the first cell 104_1. For instance, the frequency start could be determined as an offset from the start physical resource block (PRB) of the CSI-RS resources for the active state of the first cell 104_1. The frequency start can be determined such that the falls within the dormant bandwidth for measurements.

[0110] If, at block 410, it is determined that the dormant measurement resources have been configured the method proceeds to block 414. At block 414 the configured dormant resources and dormant bandwidth are used.

[0111] Once the resources and bandwidth for measurements have been determined, then at block 416 the UE 106 performs measurements and measurement reporting for the first cell 104_1 using the determined resources and bandwidth. The UE 106 does not monitor the PDCCH for the first cell 104_1. The UE 106 does monitor the PDCCH for one or more other active cells such as a second cell 104_2.

[0112] The measurements that are performed can comprise any suitable measurements. For example the measurements can comprise obtaining automatic gain control (AGC) by reading SSB, tracking reference signal (TRS) or any other suitable signal. The UE 106 can report CSI or any other suitable information.

[0113] Fig. 5A and 5B show example cell states and measurement bandwidths.

[0114] Fig. 5A shows three different states that a cell (or carrier) can be configured in. The first state is an active state 500 in which the UE 106 performs measurements and monitors PDCCH for the cell. The second state is a deactivated state 502 in which the UE 106 does not perform any channel measurements and does not monitor PDCCH for the cell. The third state is the dormant state 504 which is in-between the active state 500 and the deactivated state 502. In the dormant state 504 the UE 106 does not monitor PDCCH for the cell but it does perform some measurements for the cell. The measurements that are performed for the dormant state 504 are reduced compared to the measurements that are performed for the active state.

[0115] Fig. 5B schematically shows examples of how the measurements that are performed for the dormant state 504 are reduced compared to the measurements that are performed for the active state.

[0116] Fig. 5B shows the configured bandwidth 510 for performing measurements and reporting in the active state 500. The SSB 512 is comprised within the configured bandwidth 510.

[0117] Fig. 5B shows a first example 514 of the resources that can be used for performing measurements and reporting in the dormant state 504. In the first example 514 the UE 106 is provided with a dormant bandwidth 516. The dormant bandwidth 516 is the maximum bandwidth that can be used for measurements and reporting. The dormant bandwidth 516 can be standardized as fixed value that is common to all UEs 106, can be configured value, or can be provided via a configuration that is specific to the UE 106. The dormant bandwidth 516 is different to the active bandwidth 510. The dormant bandwidth 516 is narrower than the active bandwidth 510.

[0118] In the first example 514 the start of the resources is offset 518 from the start of the resources used for the active state 500. The offset 518 can be such that the SSB 512 is comprised within the dormant bandwidth 516.

[0119] Fig. 5B also shows a second example 520 of the resources that can be used for performing measurements and reporting in the dormant state 504. In the second example 520 the UE 106 is also provided with the dormant bandwidth 516 but this bandwidth can start anywhere.

[0120] Fig. 6 shows example transitions to an active state. The first example 600 shows a transition for a cell from a deactivated state to an active state and the second example 602 shows a transition for a cell from a dormant state to an active state. In the first example 600 the UE 106 receives a cell activation command 604 and the responds with a HARQ signal 606. After the HARQ signal the UE 106 then performs measurements for the cell by monitoring SSB 608 and TRS 610 and then performing CSI reporting 612. The cell is switched to the active state after the CSI reporting 612, This results in a delay between the UE 106 receiving the cell activation command 604 and the cell being activated.

[0121] In the second example 600 the UE 106 receives a cell activation command 604 and the responds with a HARQ signal 606. In this case the measurements were performed while the cell was in the dormant state and so the cell is switched to the active state after the HARQ signa 606. This therefore shows that fast switching from a low power, dormant state to an active state can be achieved using examples of the disclosure.

[0122] In the examples described herein reference is made to active, dormant and deactivated cells. The examples of the disclosure can be extended to scenarios in which there are carriers, rather than cells, that can be in active, dormant and deactivated states.

[0123] Fig. 7 shows an example controller 700. The controller 700 could be provided within a UE 106 or a network node 102 any other suitable entity. Implementation of the controller 700 may be as controller circuitry. The controller 700 may be implemented in hardware alone, have certain aspects in software including firmware alone or can be a combination of hardware and software (including firmware). The controller 700 can be used to control a device comprising multiple radio subsystems or could be used to control one or more of the radio subsystems within a device. The controller 700 can provide an apparatus for implementing the disclosure of could be provided as part of an apparatus that implements the disclosure.

[0124] As illustrated in Fig. 7 the controller 700 can be implemented using instructions that enable hardware functionality, for example, by using executable instructions of a computer program 706 in a general-purpose or special-purpose processor 702 that may be stored on a computer readable storage medium (disk, memory etc.) to be executed by such a processor 702.

[0125] The processor 702 is configured to read from and write to the memory 704. The processor 702 may also comprise an output interface via which data and / or commands are output by the processor 702 and an input interface via which data and / or commands are input to the processor 702.

[0126] The memory 704 stores a computer program 706 comprising computer program instructions (computer program code) that controls the operation of the apparatus when loaded into the processor 702. The computer program instructions, of the computer program 706, provide the logic and routines that enables the apparatus to perform the methods illustrated in the Figs. The processor 702 by reading the memory 704 is able to load and execute the computer program 706.

[0127] In some examples where the controller 700 is provided within an apparatus that controls a first radio subsystem, the controller therefore comprises means for: receiving from a network node an indication that a first cell is in a dormant state and information for enabling measurements associated with the first cell while the first cell is in the dormant state; and performing measurements for the first cell while the first cell is in the dormant state in accordance with the received information.

[0128] In some examples where the controller 700 is provided within an apparatus that controls a first radio subsystem, the controller therefore comprises means for: sending to a user equipment (UE) an indication that a first cell is in a dormant state and information for enabling measurements associated with the first cell while in the dormant state where the measurements are at least one of: performed on bandwidth narrower than the bandwidth used for measurements when the first cell is in an active state; performed on bandwidth different than the bandwidth used for measurements when the first cell is in an active state; reported less frequently than when the first cell is in an active state.

[0129] The computer program 706 may arrive at the apparatus via any suitable delivery mechanism 708. The delivery mechanism 708 may be, for example, a machine-readable medium, a computer-readable medium, a non-transitory computer-readable storage medium, a computer program product, a memory device, a record medium such as a Compact Disc Read-Only Memory (CD-ROM) or a Digital Versatile Disc (DVD) or a solid- state memory, an article of manufacture that comprises or tangibly embodies the computer program 706. The delivery mechanism may be a signal configured to reliably transfer the computer program 706. The apparatus may propagate or transmit the computer program 706 as a computer data signal.

[0130] The computer program 706 can comprise computer program instructions for causing an apparatus to perform at least the following or for performing at least the following: receiving from a network node an indication that a first cell is in a dormant state and information for enabling measurements associated with the first cell while the first cell is in the dormant state; and performing measurements for the first cell while the first cell is in the dormant state in accordance with the received information.

[0131] The computer program 706 can comprise computer program instructions for causing an apparatus to perform at least the following or for performing at least the following: sending to a user equipment (UE) an indication that a first cell is in a dormant state and information for enabling measurements associated with the first cell while in the dormant state where the measurements are at least one of: performed on bandwidth narrower than the bandwidth used for measurements when the first cell is in an active state; performed on bandwidth different than the bandwidth used for measurements when the first cell is in an active state; reported less frequently than when the first cell is in an active state.

[0132] The computer program instructions may be comprised in a computer program, a non- transitory computer readable medium, a computer program product, a machine-readable medium. In some but not necessarily all examples, the computer program instructions may be distributed over more than one computer program.

[0133] Although the memory 704 is illustrated as a single component / circuitry it may be implemented as one or more separate components / circuitry some or all of which may be integrated / removable and / or may provide permanent / semi-permanent / dynamic / cached storage.

[0134] Although the processor 702 is illustrated as a single component / circuitry it may be implemented as one or more separate components / circuitry some or all of which may be integrated / removable. The processor 702 may be a single core or multi-core processor. References to “computer-readable storage medium”, “computer program product”, “tangibly embodied computer program” etc. or a “controller”, “computer”, “processor” etc. should be understood to encompass not only computers having different architectures such as single / multi- processor architectures and sequential (Von Neumann) / parallel architectures but also specialized circuits such as field-programmable gate arrays (FPGA), application specific circuits (ASIC), signal processing devices and other processing circuitry. References to computer program, instructions, code etc. should be understood to encompass software for a programmable processor or firmware such as, for example, the programmable content of a hardware device whether instructions for a processor, or configuration settings for a fixed-function device, gate array or programmable logic device etc.

[0135] As used in this application, the term “circuitry” can refer to one or more or all of the following:

[0136] (a) hardware-only circuitry implementations (such as implementations in only analog and / or digital circuitry) and

[0137] (b) combinations of hardware circuits and software, such as (as applicable):

[0138] (i) a combination of analog and / or digital hardware circuit(s) with software / firmware and

[0139] (ii) any portions of hardware processor(s) with software (including digital signal processor(s)), software, and memory(ies) that work together to cause an apparatus, such as a mobile phone or server, to perform various functions and

[0140] (c) hardware circuit(s) and or processor(s), such as a microprocessor(s) or a portion of a microprocessor(s), that requires software (e.g. firmware) for operation, but the software might not be present when it is not needed for operation.

[0141] This definition of circuitry applies to all uses of this term in this application, including in any claims. As a further example, as used in this application, the term circuitry also covers an implementation of merely a hardware circuit or processor and its (or their) accompanying software and / or firmware. The term circuitry also covers, for example and if applicable to the particular claim element, a baseband integrated circuit for a mobile device or a similar integrated circuit in a server, a cellular network device, or other computing or network device.

[0142] The blocks illustrated in the Figs, can represent steps in a method and / or sections of code in the computer program 706. The illustration of a particular order to the blocks does not necessarily imply that there is a required or preferred order for the blocks and the order and arrangement of the block can be varied. Furthermore, it can be possible for some blocks to be omitted.

[0143] The above-described examples find application as enabling components of: automotive systems; telecommunication systems; electronic systems including consumer electronic products; distributed computing systems; media systems for generating or rendering media content including audio, visual and audio visual content and mixed, mediated, virtual and / or augmented reality; personal systems including personal health systems or personal fitness systems; navigation systems; user interfaces also known as human machine interfaces; networks including cellular, non-cellular, and optical networks; ad-hoc networks; the internet; the internet of things; virtualized networks; and related software and services.

[0144] The apparatus can be provided in an electronic device, for example, a mobile terminal, according to an example of the present disclosure. It should be understood, however, that a mobile terminal is merely illustrative of an electronic device that would benefit from examples of implementations of the present disclosure and, therefore, should not be taken to limit the scope of the present disclosure to the same. While in certain implementation examples, the apparatus can be provided in a mobile terminal, other types of electronic devices, such as, but not limited to: mobile communication devices, hand portable electronic devices, wearable computing devices, portable digital assistants (PDAs), pagers, mobile computers, desktop computers, televisions, gaming devices, laptop computers, cameras, video recorders, GPS devices and other types of electronic systems, can readily employ examples of the present disclosure. Furthermore, devices can readily employ examples of the present disclosure regardless of their intent to provide mobility.

[0145] The term ‘comprise’ is used in this document with an inclusive not an exclusive meaning. That is any reference to X comprising Y indicates that X may comprise only one Y or may comprise more than one Y. If it is intended to use ‘comprise’ with an exclusive meaning then it will be made clear in the context by referring to ‘comprising only one...’ or by using ‘consisting.’

[0146] In this description, the wording ‘connect’, ‘couple’ and ‘communication’ and their derivatives mean operationally connected / coupled / in communication. It should be appreciated that any number or combination of intervening components can exist (including no intervening components), i.e., to provide direct or indirect connection / coupling / communication. Any such intervening components can include hardware and / or software components.

[0147] As used herein, the term "determine / determining" (and grammatical variants thereof) can include, not least: calculating, computing, processing, deriving, measuring, investigating, identifying, looking up (for example, looking up in a table, a database, or another data structure), ascertaining and the like. Also, "determining" can include receiving (for example, receiving information), accessing (for example, accessing data in a memory), obtaining and the like. Also, " determine / determining" can include resolving, selecting, choosing, establishing, and the like.

[0148] In this description, reference has been made to various examples. The description of features or functions in relation to an example indicates that those features or functions are present in that example. The use of the term ‘example’ or ‘for example’ or ‘can’ or ‘may’ in the text denotes, whether explicitly stated or not, that such features or functions are present in at least the described example, whether described as an example or not, and that they can be, but are not necessarily, present in some of or all other examples. Thus ‘example’, ‘for example’, ‘can’, or ‘may’ refers to a particular instance in a class of examples. A property of the instance can be a property of only that instance or a property of the class or a property of a sub-class of the class that includes some but not all the instances in the class. It is therefore implicitly disclosed that a feature described with reference to one example but not with reference to another example, can where possible be used in that other example as part of a working combination but does not necessarily have to be used in that other example.

[0149] As used herein, “at least one of the following: ” and “at least one of ” and similar wording, where the list of two or more elements are joined by “and” or “or” mean at least any one of the elements, or at least any two or more of the elements, or at least all the elements.

[0150] Although examples have been described in the preceding paragraphs with reference to various examples, it should be appreciated that modifications to the examples given can be made without departing from the scope of the claims. Features described in the preceding description may be used in combinations other than the combinations explicitly described above.

[0151] Although functions have been described with reference to certain features, those functions may be performable by other features whether described or not.

[0152] The description of a feature, such as an apparatus or a component of an apparatus, configured to perform a function, or for performing a function, should additionally be considered to also disclose a method of performing that function. For example, description of an apparatus configured to perform one or more actions, or for performing one or more actions, should additionally be considered to disclose a method of performing those one or more actions with or without the apparatus.

[0153] Although features have been described with reference to certain examples, those features may also be present in other examples whether described or not.

[0154] The term ‘a’, ‘an’ or ‘the’ is used in this document with an inclusive not an exclusive meaning. That is any reference to X comprising a / an / the Y indicates that X may comprise only one Y or may comprise more than one Y unless the context clearly indicates the contrary. If it is intended to use ‘a’, ‘an’ or ‘the’ with an exclusive meaning then it will be made clear in the context. In some circumstances the use of ‘at least one’ or ‘one or more’ may be used to emphasis an inclusive meaning but the absence of these terms should not be taken to infer any exclusive meaning.

[0155] The presence of a feature (or combination of features) in a claim is a reference to that feature or (combination of features) itself and to features that achieve substantially the same technical effect (equivalent features). The equivalent features include, for example, features that are variants and achieve substantially the same result in substantially the same way. The equivalent features include, for example, features that perform substantially the same function, in substantially the same way to achieve substantially the same result.

[0156] In this description, reference has been made to various examples using adjectives or adjectival phrases to describe characteristics of the examples. Such a description of a characteristic in relation to an example indicates that the characteristic is present in some examples exactly as described and is present in other examples substantially as described.

[0157] The above description describes some examples of the present disclosure however those of ordinary skill in the art will be aware of possible alternative structures and method features which offer equivalent functionality to the specific examples of such structures and features described herein above and which for the sake of brevity and clarity have been omitted from the above description. Nonetheless, the above description should be read as implicitly including reference to such alternative structures and method features which provide equivalent functionality unless such alternative structures or method features are explicitly excluded in the above description of the examples of the present disclosure.

[0158] Whilst endeavoring in the foregoing specification to draw attention to those features believed to be of importance the Applicant may seek protection via the claims in respect of any patentable feature or combination of features hereinbefore referred to and / or shown in the drawings whether or not emphasis has been placed thereon. l / we claim:

Claims

27CLAIMS1. A user equipment (UE) comprising: at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the UE at least to perform: receiving from a network node an indication that a first cell is in a dormant state and information for enabling measurements associated with the first cell while the first cell is in the dormant state; and performing measurements for the first cell while the first cell is in the dormant state in accordance with the received information.

2. The UE of claim 1 wherein the bandwidth used for measurements for the first cell while the first cell is in the dormant state is at least one of: different to the bandwidth used for measurements for the first cell while the first cell is in an active state; and narrower than the bandwidth used for measurements for the first cell while the first cell is in an active state.

3. The UE of any of claims 1 or 2 wherein the measurements for the first cell while the first cell is in the dormant state are performed less frequently than the measurements for the first cell while the first cell is in an active state.

4. The UE of any of claims 1 to 3 wherein the processor and at least one memory are also arranged to cause the UE to perform changing the state of the first cell from a dormant state to an active state in response to a trigger condition.

5. The UE of any of claim 4 wherein changing the state of the first cell from a dormant state to an active state comprises applying results from measurements made while the first cell is in the dormant state to start monitoring for messages from the first cell.

6. The UE of any of claims 4 to 5 wherein changing the state of the first cell from a dormant state to an active state comprises reporting measurements for a wider bandwidth.

7. The UE of any of claims 1 to 6 wherein the information for enabling measurements while the first cell is in a dormant state comprises at least one of: a first resource to be used for the measurements; a bandwidth to be used for the measurements; intervals between measurements; intervals between measurement reports.

8. The UE of claim 7 wherein the bandwidth to be used for performing measurements while the first cell is in a dormant state is one of; set as a fixed value; a configured value.

9. The UE of any of claims 7 to 8 wherein the first resource is based on a configuration of the first cell when the first cell is in an active state.

10. The UE of any of claims 7 to 8 wherein the first resource is configured for the dormant state of the first cell.

11. The UE of any of claims 1 to 10 wherein the indication that the first cell is in a dormant state and information for enabling measurements associated with the first cell is received in at least one of: a radio resource control message; a medium access control element; layer 1 or layer 2 signaling.

12. The UE of any of claims 1 to 11 wherein the indication that the first cell is in a dormant state is received with activation or deactivation information for one or more cells.

13. The UE of any of claims 1 to 11 wherein the indication that the first cell is in a dormant state is received as independent signalling.

14. The UE of any of claims 1 to 13 wherein the trigger condition for changing the state of the of the first cell from a dormant state to an active state comprises at least one of: an indication comprised in signalling to the UE;being scheduled a block of data that exceeds threshold conditions for a second cell; being scheduled a block of data on the first cell via a scheduling message on another cell; receiving a request of measurement reporting for the first cell when the first cell is in a dormant state.

15. The UE of any of claims 1 to 14 wherein the processor and at least one memory are also arranged to cause the UE to perform receiving an indication that the first cell has been switched from the dormant state to a deactivated state and stopping the measurements for the first cell.

16. A method comprising; receiving from a network node an indication that a first cell is in a dormant state and information for enabling measurements associated with the first cell while the first cell is in the dormant state; and performing measurements for the first cell while the first cell is in the dormant state in accordance with the received information.

17. A network node comprising: at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the network node at least to perform: sending to a user equipment (UE) an indication that a first cell is in a dormant state and information for enabling measurements associated with the first cell while in the dormant state where the measurements are at least one of: performed on bandwidth narrower than the bandwidth used for measurements when the first cell is in an active state; performed on bandwidth different than the bandwidth used for measurements when the first cell is in an active state; reported less frequently than when the first cell is in an active state.

18. A network node as claimed in claimed 17 wherein the processor and at least one memory are also arranged to cause the network node to perform enabling the first cell to switch from the dormant state to an active state by sending to the UE an indication that the first cell is switching from the dormant state to the active state.

19. A network node as claimed in any of claims 17 to 18 wherein the processor and at least one memory are also arranged to cause the network node to perform enabling the first cell to switch from the active state to the dormant sate by sending to the UE an indication that the first cell is switching from the active state to the dormant state.

20. A method comprising: sending to a user equipment (UE) an indication that a first cell is in a dormant state and information for enabling measurements associated with the first cell while in the dormant state where the measurements are at least one of: performed on bandwidth narrower than the bandwidth used for measurements when the first cell is in an active state; performed on bandwidth different than the bandwidth used for measurements when the first cell is in an active state; reported less frequently than when the first cell is in an active state.

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