DRX cycles

Abstract

Examples of the disclosure relate to selecting a DRX cycle or an Extended DRX (eDRX) for use. At apparatus can determine that one or more DRX / eDRX cycles are configured for the apparatus. The apparatus can make a selection of a DRX / eDRX cycle for use by the apparatus from the one or more DRX / eDRX cycles that are configured for the apparatus. The apparatus can report the selected DRX / eDRX cycle to a network node.

Description

[0001] TITLE

[0002] DRX Cycles

[0003] TECHNOLOGICAL FIELD

[0004] Examples of the disclosure relate to Discontinuous Reception (DRX) Cycles. Some relate to selecting a DRX cycle or an Extended DRX (eDRX) for use.

[0005] BACKGROUND

[0006] Discontinuous Reception (DRX) enables a User Equipment to monitor control or paging channels occasionally and sleep the rest of the time. Extended DRX (eDRX) can be used to extend the cycle and provide further power savings. Different nodes or cells within a network might have different DRX / eDRX capabilities or configurations.

[0007] BRIEF SUMMARY

[0008] According to various, but not necessarily all, examples of the disclosure there may be provided an apparatus comprising: means for determining that one or more discontinuous reception cycles are configured for the apparatus; means for making a selection of a discontinuous reception cycle for use by the apparatus from the one or more discontinuous reception cycles that are configured for the apparatus; and means for reporting the selected discontinuous reception cycle to a network node.

[0009] The apparatus may comprise: means for making another selection of a discontinuous reception cycle for use by the apparatus wherein the another selection is made from the one or more discontinuous reception cycles that are configured for the apparatus; means for determining a change between the selection and the another selection in the one or more discontinuous reception cycles to be used by the apparatus; and means for triggering reporting of the another selection of a discontinuous reception cycle based on determining that there is a change in the discontinuous reception cycle to be used by the apparatus.

[0010] The making the another selection may be at least in part be responsive to at least one of the following: selection or re-selection of a different cell by the apparatus wherein the different cell is a different cell to the current cell of the apparatus; a change in system information.

[0011] The selection and / or the another selection performed by the apparatus may be made based at least in part on system information for a cell used by the apparatus.

[0012] The apparatus may comprise means for receiving a request from the network node to report which discontinuous reception cycle is being used.

[0013] The means for making a selection may be for selecting the discontinuous reception cycle while the apparatus is in an IDLE state or an INACTIVE state.

[0014] The apparatus may comprise means for receiving paging signals from the network node using the selected discontinuous reception cycle.

[0015] The discontinuous reception cycle may be one of the following:

[0016] IDLE discontinuous reception;

[0017] IDLE extended discontinuous reception;

[0018] INACTIVE discontinuous reception;

[0019] INACTIVE extended discontinuous reception;

[0020] INACTIVE enhanced extended discontinuous reception.

[0021] The selected discontinuous reception cycle may be reported using at least one of the following: Medium Access Control signalling;

[0022] Radio Resource Control signalling;

[0023] Non-Access Stratum signalling.

[0024] The selected discontinuous reception cycle may be reported using one of the following: a Medium Access Control Control Element a Common Control Channel Logical Channel Identification a Common Control Channel extended Logical Channel Identification one or more information elements within a Radio Resource Control message.

[0025] The Radio Resource Control message may comprise a connection setup message or a connection resume message.

[0026] The connection setup message or connection resume message may comprise at least one of the following: a Radio Resource Control setup message; a Radio Resource Control resume message.

[0027] The apparatus may comprise means for transmitting an indication of the discontinuous reception cycle that the apparatus will use in IDLE and / or INACTIVE state wherein the indication is transmitted to a network when the apparatus is in a CONNECTED state.

[0028] The apparatus may comprise a User Equipment.

[0029] According to various, but not necessarily all, examples of the disclosure there may be provided a method comprising: determining that one or more discontinuous reception cycles are configured for an apparatus; making a selection of a discontinuous reception cycle for use by the apparatus from the one or more discontinuous reception cycles that are configured for the apparatus and reporting the selected discontinuous reception cycle to a network node. According to various, but not necessarily all, examples of the disclosure there may be provided a computer program comprising instructions which, when executed by an apparatus, cause the apparatus to perform at least the following: determining that one or more discontinuous reception cycles are configured for an apparatus; making a selection of a discontinuous reception cycle for use by the apparatus from the one or more discontinuous reception cycles that are configured for the apparatus; and reporting the selected discontinuous reception cycle to a network node.

[0030] According to various, but not necessarily all, examples of the disclosure there may be provided a network node comprising: means for receiving a report of a selected discontinuous reception cycle being used by an apparatus; and means for using the selected discontinuous reception cycle to page the apparatus.

[0031] The discontinuous reception cycle may be reported in response to determining a change in the discontinuous reception cycle to be used by the apparatus.

[0032] The network node may comprise means for transmitting a request to an apparatus requesting that the apparatus reports the discontinuous reception cycle that is being used by the apparatus.

[0033] The network node may comprise means for transmitting an indication of the discontinuous reception cycle being used by the apparatus to another network node.

[0034] The network node may comprise an access node.

[0035] The selection and / or reselection may be made by the apparatus based at least in part on system information for a cell used by the apparatus.

[0036] According to various, but not necessarily all, examples of the disclosure there may be provided a method comprising: receiving a report of a selected discontinuous reception cycle being used by an apparatus; and using the selected discontinuous reception cycle to page the apparatus.

[0037] According to various, but not necessarily all, examples of the disclosure there may be provided a computer program comprising instructions which, when executed by a network node, cause the network node to perform at least the following: receiving a report of a selected discontinuous reception cycle being used by an apparatus; and using the selected discontinuous reception cycle to page the apparatus.

[0038] 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 of 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 of 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.

[0039] BRIEF DESCRIPTION

[0040] Some examples will now be described with reference to the accompanying drawings in which:

[0041] FIG. 1 shows an example network;

[0042] FIGS. 2A and 2B show example methods;

[0043] FIG. 3 shows an example signaling chart; and

[0044] FIG. 4 shows an example controller.

[0045] 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. DEFINITIONS

[0046] CCCH Common Control Channel

[0047] CE Control Element

[0048] CN Core Network

[0049] DRX Discontinuous Reception eDRX Extended DRX eLCID Extended Logical Channel Identification

[0050] E-UTRA Evolved Universal Mobile Telecommunications System (UMTS)

[0051] Terrestrial Radio Access gNB NR base station

[0052] LCID Logical Channel Identification

[0053] MAC Medium Access Control

[0054] NAS Non-Access Stratum

[0055] O-RAN Open-Radio Access Network

[0056] PO Paging Occasion

[0057] PTW Paging Time Window

[0058] RAN Radio Access Network

[0059] RF Radio Frequency

[0060] RRC Radio Resource Control

[0061] UE User Equipment

[0062] DETAILED DESCRIPTION

[0063] Fig. 1 illustrates an example of a network 100 such as a 5G NR network. The network 100 comprises a plurality of different types of entities 110, 120, 130. The different types of entity can comprise terminal apparatus 110, network nodes 120 and core network nodes 130 and / or any other suitable type of entity.

[0064] The network nodes 120 can be configured to communicate with the terminal apparatus

[0065] 110. The one or more core network nodes 130 communicate with the network nodes 120. In some examples the one or more core network nodes 130 communicate with the terminal apparatus 110.

[0066] The one or more core network nodes 130 can, in some examples, communicate with each other. The one or more network nodes 120 can, in some examples, communicate with each other.

[0067] The network 100 can be a cellular network comprising a plurality of cells 122. Each of the cells served by a network node 120. The network node 120 can provide an access node. In this example, the interface between the terminal apparatus 110 and a network node 120 defining a cell 122 is a wireless interface 124.

[0068] The network node 120 comprises one or more cellular radio transceivers. The terminal apparatus 110 comprises one or more cellular radio transceivers.

[0069] In the example illustrated the cellular network 100 is a third generation Partnership Project (3GPP) network in which the terminal apparatus 110 are user equipment (UE) and the network nodes 120 can be access nodes such as base stations (gNB).

[0070] The term ‘user equipment’ is used to designate mobile equipment comprising a smart card for authentication / encryption etc. such as a Subscriber Identity Module (SIM). In some examples the term ‘user equipment’ is used to designate mobile equipment comprising circuitry embedded as part of the user equipment for authentication / encryption such as software SIM.

[0071] The network node 120 can be a base station. The network node 120 can be any suitable type of base station. A base station is an access node. The network node 120 can be a network entity responsible for radio transmission and reception in one or more cells to or from the UE 110. The network node 120 can be a network element in a Radio Access Network (RAN), an Open-Radio Access Network (O-RAN), a E-UTRA (Evolved Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access) network, or any other suitable type of network. The core network node 130 can be part of a core network. The core network node 130 can be configured to manage functions relating to connectivity for the UEs 110. For example, the core network node 130 can be configured to manage functions such as connectivity, mobility, authentication, authorization and / or other suitable functions.

[0072] In the example of Fig. 1 the core network node 130 is shown as a single entity. In some examples the core network node 130 could be distributed across a plurality of entities. For example, the core network node 130 could be cloud based or distributed in any other suitable manner.

[0073] The network 100 can be a 4G or 5G network, for example. It can for example be a New Radio (NR) network that uses gNB or eNB as access nodes 120. New Radio is the 3GPP name for 5G technology. In such cases the network apparatus 120 can comprise gNodeBs (gNBs) 120 configured to provide user plane and control plane protocol terminations towards the UE 110 and / or to perform any other suitable functions. The gNBs 120 are interconnected with each other by means of an interface 126. The gNBs 120 are also connected by means of the N2 interface 128 to the core network apparatus 130. Other types of networks and interfaces could be used in other examples. Other types of networks could comprise next generation mobile and communication network, for example, a 6G network.

[0074] DRX and eDRX can be used by entities within the network 100. DRX enables a terminal apparatus such as UE 110 to monitor control or paging channels occasionally and sleep the rest of the time. Extended DRX (eDRX) can be used to extend the cycle and provide further power savings.

[0075] The network 100 can indicate the DRX cycles and eDRX cycles that can be used by a UE 110. For example, the network can indicate whether a type of DRX or eDRX cycle is allowed to be used. For example, in 3GPP rel-17 eDRX-Allowedldle and eDRX-Allowedlnactive were specified: eDRX-Allowedldle

[0076] The presence of this field indicates that extended DRX for Core Network (CN) paging is allowed in the cell for UEs in RRCJDLE or RRCJNACTIVE. The UE shall stop using extended DRX for CN paging in RRCJDLE or RRCJNACTIVE if eDRX- Allowedldle is not present. e D RX- A 11 owed I n active

[0077] The presence of this field indicates that extended DRX for Radio Access Network (RAN) paging is allowed in the cell for UEs in RRCJNACTIVE. The UE shall stop using extended DRX for RAN paging in RRCJNACTIVE if eDRX-Allowedlnactive is not present.

[0078] Problems can arise if a UE 110 is camping on a cell that does not allow an eDRX cycle that the UE 110 has been using. For instance, if a UE 110 that is in an IDLE state or an INACTIVE state selects a different cell as an anchor cell the different cell could be configured for the UE 110 to use a different DRX cycle or eDRX cycle to that currently being used by the UE 110. This can result in a change in the DRX or eDRX cycle to be used by the UE 110. The core network 130 or Radio Access Network (RAN) might not be aware of this change because the UE 110 does not inform the RAN of the cell that it is resting on.

[0079] As an illustrative example, a UE 110 can move from a first cell that allows IDLE eDRX to a second cell that does not allow IDLE eDRX. In such examples, when the UE 110 moves to the second cell the UE 110 will monitor paging according to IDLE DRX however the core network 130 will not be aware of this but will think that the UE 110 is still monitoring paging according to IDLE eDRX. In this case the UE 110 power is consumed unnecessarily, because the core network 130 will page according to eDRX cycle. In addition to the unnecessary consumption of power, there is also an unnecessary delay because the UE 110 is monitoring paging more frequently than core network 130 is aware of and so the core network 130 waits until next occasion according to eDRX cycle for paging.

[0080] Examples of the disclosure look to address these issues.

[0081] Figs. 2A and 2B show example methods that can be implemented according to examples of the disclosure. Fig. 2A shows an example method that can be implemented by an apparatus. The apparatus could be a terminal apparatus such as a UE 110.

[0082] The method comprises, at block 200, determining that one or more DRX / eDRX cycles are configured for the apparatus. The one or more DRX / eDRX cycles could comprise DRX and eDRX cycles or any other suitable type of DRX cycles. The DRX / eDRX cycle could comprise at least one of: IDLE discontinuous reception; IDLE extended discontinuous reception; INACTIVE discontinuous reception; INACTIVE extended discontinuous reception; INACTIVE enhanced extended discontinuous reception or any other suitable type of DRX / eDRX cycle.

[0083] In some examples the DRX / eDRX cycles can be a default paging cycle that is used for a cell 122. In such examples the same DRX / eDRX cycles would be used by all apparatus within a cell 122. In some examples the DRX / eDRX cycles could be specific to an apparatus or to a subset of apparatus within a cell 122. In such examples different DRX / eDRX cycles would be used by different apparatus within a cell 122.

[0084] At block 202 the method comprises making a selection of a DRX / eDRX cycle for use by the apparatus from the one or more DRX / eDRX cycles that are configured for the apparatus. The selection can be made, based at least in part on system information for a cell used by the apparatus;

[0085] The DRX / eDRX for use by the apparatus can be selected while the apparatus is in an IDLE state or an INACTIVE state.

[0086] The DRX / eDRX for use by the apparatus can be selected based, at least in part, on system information for a cell used by the apparatus. For instance, the system information for a cell used by the apparatus can indicate the DRX / eDRX cycles that are allowed for the cell and the apparatus can select one of the allowed DRX / eDRX cycles. The system information can comprise IDLE eDRX allowed, INACTIVE eDRX allowed and INACTIVE enhanced eDRX allowed information. In some examples, DRX cycle(s) other than eDRX are always allowed in a cell. In some examples the system information that provides the DRX / eDRX information could comprise an RRC message such as a System Information Block message. The cell used by the apparatus is the cell that the apparatus uses to stay connected to the network. It is the cell that a UE is camping in (in RRCJDLE or RRCJNACTIVE state) and is the cell a UE would use to access the network (IN RRC_CONNECTED mode) should there be a trigger to get connected (for example, data transmission).

[0087] At block 204 the method comprises reporting the selected DRX / eDRX to a network node 120. The network node 120 that the report is sent to can be an anchor network node for the apparatus or any other suitable network node 120. In some examples the network node 120 can be an access node for a cell that the apparatus is camped on.

[0088] Any suitable types of signaling can be used to report the selected DRX / eDRX to the network node 120. In some examples control signaling can be used to report the selected DRX / eDRX to the network node 120. In some examples the control signaling can be between an apparatus and an access node 120. In some examples the control signaling can be between an apparatus and the core network 130. In some examples the selected DRX / eDRX can be reported using at least one of: Medium Access Control (MAC) signaling; Radio Resource Control (RRC) signaling; Non-Access Stratum (NAS) signaling or any other suitable type of signaling.

[0089] In some examples the selected DRX / eDRX can be reported using at least one of: a MAC Control Element (CE), a Common Control Channel (CCCH) Logical Channel Identification (LCID) value, a CCCH extended Logical Channel Identification (eLCID) value, one or more information elements within an RRC message. For example, the one or more information elements in an RRC message can comprise an establishment cause value or a resume cause value.

[0090] In examples where an RRC message is used to report the selected DRX / eDRX cycle the RRC message can comprise a connection setup message or a connection resume message or any other suitable type of message. The connection setup message or connection resume message comprises at least one of: an RRC setup message; an RRC resume message. In some examples the RRC Setup or RRC Resume procedure can be initiated by the apparatus so as to report the selected DRX / eDRX cycle to the network node 120. The method can comprise blocks that are not shown in Fig. 2A. In some examples the method can comprise making another selection of a DRX / eDRX cycle. The another selection is made from the one or more discontinuous reception cycles that are configured for the apparatus The another selection can be made at a later point in time than the first selection. The apparatus can be configured to determine a change in one or more DRX / eDRX cycles that are to be used by the apparatus. The change that is determined can be a change in the DRX / eDRX cycle that is being used. For instance, it could be a switch from using eDRX to using DRX or any other suitable type of change. As an example a change in the DRX / eDRX cycle that is being used could be a change from INACTIVE (enhanced) eDRX to INACTIVE DRX or from INACTIVE enhanced eDRX to INACTIVE eDRX).

[0091] Any suitable means or process can be used to determine the change in the DRX / eDRX cycles that are to be used by the apparatus. For instance, the change can be determined by reading system information for a cell 122 used by the apparatus and comparing the system information to the DRX / eDRX cycles that are configured for the apparatus. Specifically, it is the DRX / eDRX within the system information that would be compared to the DRX / eDRX cycles that are configured for the apparatus.

[0092] In examples where a change in the one or more DRX / eDRX cycles is determined the apparatus can be configured to trigger reporting of the selected discontinuous reception cycle based on determining that there is a change in the DRX / eDRX to be used by the apparatus. For instance, if the selection of the DRX / eDRX cycle causes a change then this can be reported however if the selection of the DRX / eDRX does not cause a change then this does not need to be reported.

[0093] There are multiple scenarios that could cause the change in the DRX / eDRX cycles that are to be used by the apparatus. For instance, the change could arise due to the selection or reselection of a different cell by the apparatus wherein the different cell is a different cell to the current cell of the apparatus. For instance, if the apparatus moves from a first cell to a second cell the apparatus might not be configured with a DRX / eDRX that is allowed on the second cell. This means that the apparatus would need to change or update the DRX / eDRX cycle that is being used. In some examples the change could arise due to a change in system information of a cell. A system information change could comprise the network changing the allowance status of one or more DRX / eDRX cycles for one or more cells. The change in the DRX / eDRX cycles could be determined following the occurrence of any of these events.

[0094] There might be some scenarios where the reporting of the selected DRX / eDRX might not be triggered. For example, if all of the DRX / eDRX cycles that are configured for the apparatus are allowed in a different cell that the apparatus selects or reselects or if the system information changes then the selected DRX / eDRX does not need to be reported because it is allowed. For example, if the system information changes to allow all types of DRX / eDRX then no reporting of the DRX / eDRX would be needed because all of the DRX / eDRX cycles that are configured for the apparatus would be allowed.

[0095] In some examples the method can comprise receiving a request from the network node to report which discontinuous reception cycle is being used. The request could be received using dedicated signaling. For instance, the request could be made using an RRC Reconfiguration or RRC Release message. In some examples the request could be received using broadcast signalling such as system information. In some examples the report can be sent in response to the request.

[0096] After the apparatus has reported the DRX / eDRX cycles that are being used the apparatus can receive paging signals from the network node. The paging signals can be received using the selected DRX / eDRX cycle that has been reported to the network node.

[0097] In some examples the reporting of the selected DRX / eDRX cycle can be performed when the apparatus is in CONNECTED state. For instance, an apparatus can be configured to transmit a report of the DRX / eDRX that the apparatus will use in IDLE and / or INACTIVE state wherein the indication is transmitted to a network node when the apparatus is in a CONNECTED state. For example, UE Assistance information message (RRC message) can be used to transmit the indication. Fig. 2B shows an example method that can be implemented by a network node such as gNB 120 or a core network node 130. The method of Fig. 2B corresponds to the method of Fig. 2A in that the method can be performed by a network node 120 that receives the report of the selected DRX / eDRX cycle.

[0098] The method comprises, at block 210, receiving a report of a selected DRX / eDRX cycle being used by an apparatus. The apparatus could be a terminal apparatus such as a UE 110. The apparatus could be camped on a cell comprises the network node 120.

[0099] In some examples the DRX / eDRX cycle is reported in response to determining a change in the DRX / eDRX cycle to be used by the apparatus. The determining can be performed by the apparatus. In such cases the network node 120 might only receive reports of the selected DRX / eDRX cycles when a change occurs.

[0100] At block 212 the method comprises using the selected DRX / eDRX cycle to page the apparatus.

[0101] The method can comprise blocks that are not shown in Fig. 2B. In some examples the method can comprise transmitting a request to an apparatus requesting that the apparatus reports the discontinuous reception cycle that is being used by the apparatus.

[0102] In some examples the network node 120 can be configured to share information about the report DRX / eDRX cycles with other nodes in the network 100. For instance, the network node 120 can be configured to transmit an indication of the discontinuous reception cycle being used by the apparatus to another network node. The another network node could be an access node 120 or a core network node 130. For instance, the network node 120 that receives the report from the apparatus can be configured to transmit an indication of the DRX / eDRX cycle that the apparatus is using to an anchor gNB 120 of the apparatus in RRCJNACTIVE mode. In such examples the report could indicate that the apparatus is using a specific DRX cycle of RRCJNACTIVE mode, such as RRCJNACTIVE DRX or RRCJNACTIVE (enhanced) eDRX)). In some examples the apparatus could be to the CN for an apparatus in RRCJDLE mode. In such examples the report could indicate that the apparatus is using a specific DRX cycle of RRCJDLE mode, such as RRCJDLE DRX or RRCJDLE eDRX.

[0103] The reporting of the selected DRX / eDRX cycles from the apparatus to the network node 120 helps to ensure that the apparatus is synchronized with the Radio Access Network (RAN) and / or the Core Network (CN). This reduces power wastage caused by the apparatus listening for paging when the network is not paging. This can also reduce delays by ensuring that the network is not waiting longer than necessary for a paging interval.

[0104] Fig. 3 shows an example signaling chart that can be used to implement examples of the disclosure.

[0105] In the example of Fig. 3 the signaling is shown as being between a UE 110, a first cell 122_1 and second cell 122_2. The first cell 122_1 and the second cell 122_2 could be provided by different gNBs 120. In some examples the first cell 122_1 and the second cell 122_2 could be provided by the same gNB 120.

[0106] At block 300_1 the first cell 122_1 signals the allowed eDRX modes for the first cell 122_1. An allowed eDRX mode is one that is indicated as allowable in the system information for a given cell. Similarly at block 300_2 the second cell 122_2 signals the allowed eDRX modes for the second cell 122_2. For example, the respective cells can include eDRX-Allowedldle or eDRX-Allowedlnactive in the system information based on whether or not these eDRX modes are allowed in the respective cells 122.

[0107] In this illustrative example the first cell 122_1 signals that eDRX is allowed in both IDLE mode and INACTIVE mode. In this case the first cell 122_1 will signal both eDRX- Allowedldle and eDRX-Allowedlnactive. The second cell 122_2 signals that eDRX is allowed in IDLE mode but not in INACTIVE mode. In this case the second cell 122_2 will signal eDRX-Allowedldle but not eDRX-Allowedlnactive.

[0108] In this example the first cell 122_1 is the anchor cell 122 for the UE 110. The second cell 122_2 can be a cell that the UE 110 moves to or camps on. At block 302 the UE 110 is released from and active mode by the first cell 122_1. The UE 110 could be released into IDLE mode or INACTIVE mode. The UE 110 can be released into the IDLE mode or INACTIVE mode with DRX / eDRX configurations. That is, one or more DRX / eDRX cycles are configured for the UE 110.

[0109] In this case the one or more DRX / eDRX cycles are configured for the UE 110 comprising the DRX / eDRX cycles that are allowed by the first cell 122_1. In this case the one or more DRX / eDRX cycles are configured for the UE 110 can therefore comprises eDRX IDLE, eDRX INACTIVE, and / or enhanced eDRX INACTIVE.

[0110] At block 304 the network can allow or request that the UE 110 reports which DRX / eDRX cycle the UE 110 is using. This can be an optional block. That is, this block need not be used in all examples of the disclosure.

[0111] The network can use any suitable signalling to or request that the UE 110 reports which DRX / eDRX cycle the UE 110 is using. In some examples the request could be made using dedicated signaling. For instance, the request could be made using an RRC Reconfiguration or RRC Release message transmitted via the first cell 122_1 to the UE 110. In some examples the request could be made using broadcast signalling such as system information.

[0112] At block 306 the UE reselects to the second cell 122_2. For example, the UE 110 can remain in the IDLE mode or the INACTIVE mode while it camps on the second cell 122_2. In this scenario because the UE 110 is not in an active mode the network doesn’t necessarily know that the UE 110 is camped on a different cell and there is no handover procedure. The first cell 122_1 will remain the one that the UE would use if it was triggered to start an RRC connect procedure.

[0113] At block 308 the UE 110 acquires the system information for the second cell 122_2. The UE 110 can then determine if the DRX / eDRX cycles that have been configured for the UE 110 are allowed in the second cell 122_2. The UE 110 can determine if the DRX / eDRX cycles are allowed by comparing the acquired system information with information indicating the DRX / eDRX cycles that were configured for the UE 110 at block 302. In this case two different scenarios can arise. In a first scenario the UE 110 is IDLE mode and so would be using eDRX IDLE. This is allowed in both the first cell 122_1 and the second cell 122_2. In this case, at block 310, the UE 110 would continue to use the eDRX cycle. Specifically, the UE 110 would continue the eDRX IDLE cycle. There would be no change in the eDRX cycle that is being used. In this case no new DRX / eDRX cycle is selected and there would not need to be a report of the DRX / eDRX cycle that is being used.

[0114] In a second scenario the UE 110 is INACTIVE mode and so would be using eDRX INACTIVE. This is allowed in the first cell 122_1 but not the second cell 122_2. In this case, at block 312, the UE 110 would start to use the DRX cycle. Specifically, the UE 110 would change from eDRX INACTIVE cycle to DRX INACTIVE cycle. In this case new DRX / eDRX cycle has been selected and it would be beneficial to report the DRX / eDRX cycle that has been selected.

[0115] At block 314 the UE determines whether the DRX cycle has changed. The change can be determined by comparing the system information for the second cell 122_2 with the DRX / eDRX cycles that were originally configured for the UE 110.

[0116] In the first of the above-mentioned scenarios there would be no change in the DRX / eDRX cycle used and so there would be no need to report the selected DRX / eDRX cycle. In the second of the above-mentioned scenarios there is a change in the DRX / eDRX cycle used and so the method would proceed to block 316 and the UE 110 would report the selected DRX / eDRX cycle to the second cell 122_2. Any suitable types of signaling can be used to report the selected DRX / eDRX to the second cell 122_2. In some examples control signaling between the UE 110 and a network node 120 can be used to report the selected DRX / eDRX to the second cell 122_2.

[0117] At block 318 the second cell 122_2 acknowledges the report of the selected DRX / eDRX cycle.

[0118] At block 320 the second cell 122_2 can indicate the DRX / eDRX cycle used by the UE 110 to the anchor gNB 120 for the UE 110. In this scenario a gNB 120 of the second cell 122_2 can indicate to a gNB 120 of the first cell 122_1 that the UE 110 is now using INACTIVE DRX.

[0119] Once the selected DRX / eDRX cycle has been reported to the network then, at block 322, the network can use the selected DRX / eDRX cycle to page the UE 110. In this case both the first cell 122_1 and the second cell 122_2 use the INACTIVE DRX cycle so as to synchronize the UE 110 with the network.

[0120] Tables 1 to 4 show examples of how an apparatus can select which DRX / eDRX cycle to use in various scenarios. In these tables the “UE configuration” column indicates an initial configuration for the UE. The “eDRX-Allowedldle broadcasted?”, “eDRX- Allowedlnactive broadcasted?”, and “enhanced eDRX-Allowedldle broadcasted” indicate whether it has been signalled to the UE that these modes are allowed. A yes in this column indicate that the respective mode is allowed and a no in these columns indicate that the respective mode is not allowed. The UE selection column indicates the eDRX cycle mode that the UE 110 selects based on the allowed modes.

[0121] The apparatus can use the system information for a cell to determine whether respective types of DRX / eDRX are allowed. The cell can be a cell the apparatus is camping on. Then by comparing the DRX / eDRX currently configured for the apparatus with the allowed eDRX mode the apparatus can select whether to keep the current DRX / eDRX cycle or to select a different DRX / eDRX cycle.

[0122] This process of comparing the DRX / eDRX currently configured for the apparatus with the allowed eDRX mode could be used by the apparatus when making any of the selections of the DRX / eDRX cycle.

[0123]

[0124] Table 2: UE in RRCJNACTIVE state

[0125]

[0126] Table 3: UE in RRCJNACTIVE state

[0127] Table 4: UE in RRCJNACTIVE state

[0128] In some examples a UE 110 can be allowed to use an eDRX cycle allowed by a previously used cell, even if the given eDRX cycle is not allowed on a currently used cell. Such eDRX cycles could be IDLE eDRX, INACTIVE eDRX, or INACTIVE enhanced eDRX. In such cases the LIE110 can be configured with one more of the following: IDLE eDRX, INACTIVE eDRX, or INACTIVE enhanced eDRX.

[0129] In some examples the UE 110 can be configured to apply the (e)DRX cycle for paging that was selected upon entering IDLE mode or INACTIVE mode. In such examples the DRX cycle or eDRX cycle can be selected based on the cell where the UE 110 is released to IDLE mode or suspended to INACTIVE mode (this is, the cell that was the PCell / Primary Cell of the UE 110 when the UE 110 receives the RRCRelease message). For example, if the UE 110 that is configured with IDLE eDRX is released to IDLE mode and eDRX-Allowedldle is signalled in the given cell (the cell that was the PCell / Primary Cell of the UE 110 when the UE 110 receives the RRCRelease message), the UE 110 applies IDLE eDRX regardless of re-selecting to a cell which does not signal eDRX-Allowedldle (this can occur regardless of IDLE eDRX not allowed). In some examples, if a UE 110 that is configured with INACTIVE (enhanced) eDRX is suspended to INACTIVE mode and eDRX-Allowedlnactive (or corresponding IE for INACTIVE enhanced eDRX) is signalled in the given cell the cell that was the PCell / Primary Cell of the UE 110 when the UE 110 receives the RRCRelease message with suspendConfig), the UE 110 applies INACTIVE (enhanced) eDRX regardless of re-selecting to a cell which does not signal eDRX-Allowedlnactive or correspondingly does not signal an IE for INACTIVE enhanced eDRX (this can occur regardless of INACTIVE (enhanced) eDRX not allowed).

[0130] In some examples, the UE 110 calculates and monitors the paging in a paging occasion (PO) in the cell it is camped on according to the DRX cycle it would select in the cell. That is, the DRX cycle is based on the selected DRX cycle upon entering IDLE / INACTIVE mode while the PO is determined based on the DRX cycle the UE 110 would use in the target cell (based on the target cell configuration). In some examples, the UE 110 can be required to monitor one or more PO(s) immediately preceding, and / or within, and / or following the paging monitoring window (for example, Paging Time Window (PTW)) of the eDRX cycle in use.

[0131] In some examples, a new indication can be specified for the network to indicate that the UE 110 shall re-apply / re-select the DRX cycle according to the configuration as provided in a given cell. For example, such indication could be provided in the system information, in a paging message, or in a short message (DCI). In some examples, upon receiving the indication, if the used / applied / selected DRX cycle is changed by the UE 110, the UE 110 triggers RRC establishment / resume procedure. For example, the UE 110 can trigger tracking / registration area update or RAN area update procedure.

[0132] Fig. 4 shows an example controller 400. The controller 400 could be provided within an entity such as an apparatus such as a UE 110 or a network node such as a gNB 120 or any other suitable apparatus. Implementation of the controller 400 may be as controller circuitry. The controller 400 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). As illustrated in Fig. 4 the controller 400 can be implemented using instructions that enable hardware functionality, for example, by using executable instructions of a computer program 406 in a general-purpose or special-purpose processor 402 that may be stored on a computer readable storage medium (disk, memory etc.) to be executed by such a processor 402.

[0133] The processor 402 is configured to read from and write to the memory 404. The processor 402 may also comprise an output interface via which data and / or commands are output by the processor 402 and an input interface via which data and / or commands are input to the processor 402.

[0134] The memory 404 stores a computer program 406 comprising computer program instructions (computer program code) that controls the operation of the apparatus when loaded into the processor 402. The computer program instructions, of the computer program 406, provide the logic and routines that enables the apparatus to perform the methods illustrated in the Figs. The processor 402 by reading the memory 404 is able to load and execute the computer program 406.

[0135] The controller 400 can be provided within an apparatus such as a UE 110. In such examples the controller 400 therefore comprises: at least one processor 402; and at least one memory 404 storing instructions that, when executed by the at least one processor 402, cause an apparatus to perform at least: determining 200 that one or more discontinuous reception cycles are configured for an apparatus; making a selection 202 of a discontinuous reception cycle for use by the apparatus from the one or more discontinuous reception cycles that are configured for the apparatus; and reporting 204 the selected discontinuous reception cycle to a network node.

[0136] The controller 400 can be provided within a network node such as a gNB 120. In such examples the controller 400 therefore comprises: at least one processor 402; and at least one memory 404 storing instructions that, when executed by the at least one processor 402, cause a network node to perform at least: receiving 210 a report of a selected discontinuous reception cycle being used by an apparatus; and using 212 the selected discontinuous reception cycle to page the apparatus.

[0137] The computer program 406 may arrive at the apparatus via any suitable delivery mechanism 408. The delivery mechanism 408 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 406. The delivery mechanism may be a signal configured to reliably transfer the computer program 406. The apparatus may propagate or transmit the computer program 406 as a computer data signal.

[0138] The computer program 406 can comprise computer program instructions for causing an apparatus to perform at least the following or for performing at least the following: determining 200 that one or more discontinuous reception cycles are configured for an apparatus; making a selection 202 of a discontinuous reception cycle for use by the apparatus from the one or more discontinuous reception cycles that are configured for the apparatus; and reporting 204 the selected discontinuous reception cycle to a network node.

[0139] The computer program 406 can comprise computer program instructions for causing an apparatus to perform at least the following or for performing at least the following: receiving 210 a report of a selected discontinuous reception cycle being used by an apparatus; and using 212 the selected discontinuous reception cycle to page the apparatus.

[0140] 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. Although the memory 404 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.

[0141] Although the processor 402 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 402 may be a single core or multi-core processor.

[0142] 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.

[0143] As used in this application, the term ‘circuitry’ may refer to one or more or all of the following:

[0144] (a) hardware-only circuitry implementations (such as implementations in only analog and / or digital circuitry) and

[0145] (b) combinations of hardware circuits and software, such as (as applicable):

[0146] (i) a combination of analog and / or digital hardware circuit(s) with software / firmware and

[0147] (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 (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 may not be present when it is not needed for operation.

[0148] 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.

[0149] The stages illustrated in the Figs, can represent steps in a method and / or sections of code in the computer program 406. 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 may be varied. Furthermore, it can be possible for some blocks to be omitted.

[0150] 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”.

[0151] 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., so as to provide direct or indirect connection / coupling / communication. Any such intervening components can include hardware and / or software components.

[0152] 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.

[0153] 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 of 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.

[0154] 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.

[0155] Features described in the preceding description may be used in combinations other than the combinations explicitly described above.

[0156] Although functions have been described with reference to certain features, those functions may be performable by other features whether described or not.

[0157] Although features have been described with reference to certain examples, those features may also be present in other examples whether described or not.

[0158] 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.

[0159] The presence of a feature (or combination of features) in a claim is a reference to that feature or (combination of features) itself and also 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.

[0160] 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.

[0161] 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.

[0162] Whilst endeavoring in the foregoing specification to draw attention to those features believed to be of importance it should be understood that 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.

Claims

CLAIMS1. An apparatus comprising: means for determining that one or more discontinuous reception cycles are configured for the apparatus; means for making a selection of a discontinuous reception cycle for use by the apparatus from the one or more discontinuous reception cycles that are configured for the apparatus; and means for reporting the selected discontinuous reception cycle to a network node.

2. The apparatus as claimed in claim 1 comprising: means for making another selection of a discontinuous reception cycle for use by the apparatus wherein the another selection is made from the one or more discontinuous reception cycles that are configured for the apparatus; means for determining a change between the selection and the another selection in the one or more discontinuous reception cycles to be used by the apparatus and; means for triggering reporting of the another selection of a discontinuous reception cycle based on determining that there is a change in the discontinuous reception cycle to be used by the apparatus.

3. The apparatus as claimed in claim 2, wherein the making the another selection is responsive at least in part to at least one of the following: selection or re-selection of a different cell by the apparatus wherein the different cell is a different cell to the current cell of the apparatus; or detection of a change in system information.

4. The apparatus as claimed in claim 2 or 3, wherein the selection and / or the another selection is made, based at least in part, on system information for a cell used by the apparatus.

5. The apparatus as claimed in any preceding claim wherein the apparatus comprises means for receiving a request from the network node to report which discontinuous reception cycle is being used.

6. The apparatus as claimed in any preceding claim wherein the means for making the selection and / or the another selection are for selecting the discontinuous reception cycle while the apparatus is in an IDLE state or an INACTIVE state.

7. The apparatus as claimed in any preceding claim comprising means for receiving paging signals from the network node using the selected discontinuous reception cycle.

8. The apparatus as claimed in any preceding claim wherein the discontinuous reception cycle is one of the following:IDLE discontinuous reception;IDLE extended discontinuous reception;INACTIVE discontinuous reception;INACTIVE extended discontinuous reception;INACTIVE enhanced extended discontinuous reception.

9. The apparatus as claimed in any preceding claim wherein the selected discontinuous reception cycle is reported using at least one of the following:Medium Access Control signalling;Radio Resource Control signalling;Non-Access Stratum signalling.

10. The apparatus as claimed in any preceding claim wherein the selected discontinuous reception cycle is reported using one of the following: a Medium Access Control Control Element a Common Control Channel Logical Channel Identification a Common Control Channel extended Logical Channel Identification one or more information elements within a Radio Resource Control message.

11. The apparatus as claimed in claim 10 wherein the Radio Resource Control message comprise a connection setup message or a connection resume message and wherein the connection setup message or connection resume message comprises at least one of the following:a Radio Resource Control setup message; a Radio Resource Control resume message.

12. The apparatus as claimed in any preceding claim wherein the apparatus comprises means for transmitting an indication of the discontinuous reception cycle that the apparatus will use in IDLE and / or INACTIVE state wherein the indication is transmitted to a network when the apparatus is in a CONNECTED state.

13. A network node comprising: means for receiving a report of a selected discontinuous reception cycle being used by an apparatus; and means for using the selected discontinuous reception cycle to page the apparatus.

14. The network node as claimed in claim 13 comprising means for transmitting a request to an apparatus requesting that the apparatus reports the discontinuous reception cycle that is being used by the apparatus.

15. The network node as claimed in any of claims 13 to 14 comprising means for transmitting an indication of the discontinuous reception cycle being used by the apparatus to another network node.

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