Random access procedure

Abstract

Examples of the disclosure relate to random access procedures with multiple network entities. In examples of the disclosure a UE receives an indication of multiple frequency layers that can be used in an initial access procedure with multiple network entities and sends a message to a first network entity of the multiple network entities. The UE receives a response from the first network entity indicating a timing advance that is valid for the first network entity and at least one second entity of the multiple network entities. The UE connects to the first network entity and the at least one second entity based, at least in part, on the received response.

Description

[0001] TITLE

[0002] Random Access Procedure

[0003] TECHNOLOGICAL FIELD

[0004] Examples of the disclosure relate to random access procedures. Some relate to random access procedures with multiple network entities.

[0005] BACKGROUND

[0006] User equipments (UE) can be configured to operate in a multi transmission / reception points (TRP) mode. In a multi-TRP mode a serving cell can schedule the UE 110 from multiple TRPs. The use of multi-TRPs can help to provide higher connection density, enhanced user experience, higher peak data throughput as well as lower latency in networks. To make use of the multi-TRPs a UE must be configured for multi-TRP operation during an access procedure.

[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 to perform at least: receiving an indication of multiple frequency layers that can be used in an initial access procedure with multiple network entities; sending a message to a first network entity of the multiple network entities; receiving a response from the first network entity indicating a timing advance that is valid for the first network entity and at least one second entity of the multiple network entities; and connecting to the first network entity and the at least one second entity based, at least in part, on the received response.

[0009] The network entities may comprise transmit / receive points (TRPs). The indication of multiple frequency layers may be received in a system information block.

[0010] The processor and the memory may be arranged to select the first network entity from the multiple network entities based on measurements.

[0011] The response from the first network entity may comprise an uplink grant valid for the first network entity.

[0012] The first network entity may comprise an uplink grant valid for the second network entity.

[0013] The uplink grant may indicate the resources related to the relevant network entity to be used by the UE during the initial access procedure.

[0014] Connecting to the first network entity and the at least one second network entity may comprise sending an identity of the UE and an indication that the UE prefers operation with multiple network entities to the first network entity.

[0015] Connecting to the first network entity and the at least one second network entity may comprise sending an identity of the UE and an indication that the UE prefers operation with multiple network entities to the second network entity.

[0016] The indication that the UE prefers operation with multiple network entities may be provided in an RRCSetupRequest wherein the RRCSetupRequest is sent in one of: msg3 of a four-step random access procedure; or msgA of a two-step random access procedure.

[0017] The first network entity and the at least one second network entity may comprise receiving a response to the indication that the UE prefers operation with multiple network entities wherein the response to the indication comprises connection information of the first network entity and the at least one second network entity and the response to the indication is received from the first network entity. The connection information may comprise at least one of: contention resolution; downlink control information; radio resource control setup.

[0018] The connection information may be received in one of: msg4 of a four-step random access procedure; or msgB of a two-step random access procedure.

[0019] The indication of multiple frequency layers that can be used in an initial access procedure with multiple network entities may also indicate multiple modes of operation for which the multiple frequency layers can be used.

[0020] The multiple modes of operation may comprise one or more of: carrier aggregation; multi-TRP operation; dual connectivity; multi carrier single cell.

[0021] According to various, but not necessarily all, examples of the disclosure there may be provided a method comprising: receiving an indication of multiple frequency layers that can be used in an initial access procedure with multiple network entities; sending a message to a first network entity of the multiple network entities; receiving a response from the first network entity indicating a timing advance that is valid for the first network entity and at least one second entity of the multiple network entities; and connecting to the first network entity and the at least one second entity based, at least in part, on the received response.

[0022] 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 a UE to perform: receiving an indication of multiple frequency layers that can be used in an initial access procedure with multiple network entities; sending a message to a first network entity of the multiple network entities; receiving a response from the first network entity indicating a timing advance that is valid for the first network entity and at least one second entity of the multiple network entities; and connecting to the first network entity and the at least one second entity based, at least in part, on the received response.

[0023] According to various, but not necessarily all, examples of the disclosure there may be provided a network entity comprising: at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the network entity to perform at least: sending, to a UE, an indication of multiple frequency layers that can be used in an initial access procedure with the network entity and at least one other network entity; receiving a message from the UE; sending a response to the UE indicating a timing advance that is valid for the network entity and the at least one other network entity; and enabling the UE to connect to the network entity and the at least one other network entity based, at least in part, on the sent response.

[0024] The network entities may comprise transmit / receive points (TRPs).

[0025] The indication of multiple frequency layers may be sent in a system information block.

[0026] The response sent to the UE may comprise an uplink grant valid for the network entity.

[0027] The response to the UE may comprise an uplink grant valid for the at least one other network entity.

[0028] The network entity may obtain the uplink grant valid for the at least one other network entity via at least one of: an Xn interface; or an Ng interface.

[0029] The network entity and the at least one other network entity may be comprised within a distributed unit.

[0030] The uplink grant may indicate the resources related to the network entity to be used by the UE during the initial access procedure.

[0031] Enabling the UE to connect to the network entity and at least one other network entity may comprise receiving an identity of the UE and an indication that the UE prefers operation with multiple network entities.

[0032] The indication that the UE prefers operation with multiple network entities may be provided in an RRCSetupRequest wherein the RRCSetupRequest is received in one of: msg3 of a four-step random access procedure; or msgA of a two-step random access procedure.

[0033] Enabling the UE to connect to the network entity and at least one other network entity may comprise sending a response to the indication that the UE prefers operation with multiple network entities wherein the response to the indication comprises connection information the network entity and the at least one other network entity.

[0034] The connection information may comprise at least one of: contention resolution; downlink control information; radio resource control setup.

[0035] The connection information may be sent in one of:

[0036] Msg4 of a four-step random access procedure; or msgB of a two-step random access procedure. The indication of multiple frequency layers that can be used in an initial access procedure with multiple network entities may also indicate multiple modes of operation for which the multiple frequency layers can be used.

[0037] The multiple modes of operation may comprise one or more of: carrier aggregation; multi-TRP operation; dual connectivity; multi carrier single cell.

[0038] According to various, but not necessarily all, embodiments there may be provided a method comprising: sending a message to a first network entity of the multiple network entities; receiving a response from the first network entity indicating a timing advance that is valid for the first network entity and at least one second entity of the multiple network entities; and connecting to the first network entity and the at least one second entity based, at least in part, on the received response.

[0039] According to various, but not necessarily all, embodiments there may be provided a computer program comprising instructions which, when executed by an apparatus, cause a UE to perform: sending a message to a first network entity of the multiple network entities; receiving a response from the first network entity indicating a timing advance that is valid for the first network entity and at least one second entity of the multiple network entities; and connecting to the first network entity and the at least one second entity based, at least in part, on the received response.

[0040] 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.

[0041] 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.

[0042] According to various, but not necessarily all, embodiments there is provided examples as claimed in the appended claims.

[0043] 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

[0044] BRIEF DESCRIPTION

[0045] Some examples will now be described with reference to the accompanying drawings in which:

[0046] FIG. 1 shows an example network;

[0047] FIGS. 2A to 2C show example access procedures;

[0048] FIG. 3 shows example collocated network entities

[0049] FIGS. 4A and 4B show example methods;

[0050] FIGS. 5A and 5B shows example access procedures; FIG. 6 shows an example access procedure;

[0051] FIGS. 7A to 70 show example methods;

[0052] FIG. 8 shows an example access procedure; and

[0053] FIG. 9 shows an example controller.

[0054] 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.

[0055] DEFINITIONS

[0056] CRI Contention Resolution Identity

[0057] C-RNTI cell - radio network temporary identifier

[0058] DCI Downlink Control Information gNB Base Station

[0059] MAC Medium Access Control

[0060] NAS Non-Access Stratum

[0061] PBCH Physical Broadcast Channel

[0062] PDCCH Physical Downlink Control Channel

[0063] PDSCH Physical Downlink Shared Channel

[0064] PDU Packet Data Units

[0065] PRACH Physical Random Access Channel

[0066] PUCCH Physical Uplink Control Channel

[0067] PUSCH Physical Uplink Shared Channel

[0068] RACH Random Access Channel

[0069] RAPID Random Access Preamble Identity

[0070] RAR Random Access Response

[0071] RO RACH Occasion

[0072] RRC Radio Resource Control

[0073] RSRP Reference Signal Received Power

[0074] SFN Single Frequency Network SIB System Information Block

[0075] SS Synchronization Signal

[0076] SSB Synchronized Signal Block

[0077] TA Timing Advance

[0078] TCI Transmission Configuration Information

[0079] TRP Transmission / Reception Point

[0080] UE User Equipment

[0081] UL Uplink

[0082] DETAILED DESCRIPTION

[0083] Fig. 1 illustrates an example of a communications network 100. The network 100 comprises a plurality of different types of nodes 110, 120, 130. The different types of nodes can comprise terminal nodes 110, network nodes 120 and core network nodes 130 and / or any other suitable type of nodes.

[0084] The network 100 in this example is a radio telecommunications network, in which at least some of the terminal nodes 110 and network nodes 120 communicate with each other using transmission / reception of radio waves.

[0085] The network nodes 120 can be configured to communicate with the terminal nodes 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 nodes 110.

[0086] 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.

[0087] The network 100 can be a cellular network comprising a plurality of cells 122. Each of the cells is served by a network node 120. The network node 120 can provide an access node. In this example, the interface between the terminal nodes 110 and a network node 120 defining a cell 122 is a wireless interface 124. The network node 120 comprises one or more cellular radio transceivers. The terminal node 110 comprises one or more cellular radio transceivers.

[0088] In the example illustrated the cellular network 100 is a third generation Partnership Project (3GPP) standard compliant network in which the terminal nodes 110 are user equipment (UE) and the network nodes 120 can be access nodes such as base stations (gNB). The UE can comprise a mobile equipment.

[0089] A 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. A 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.

[0090] The core network nodes 130 can be part of a core network. The core network nodes 130 can be configured to manage functions relating to connectivity for the UEs 110. For example, the core network nodes 130 can be configured to manage functions such as connectivity, mobility, authentication, authorization and / or other suitable functions.

[0091] 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.

[0092] In some examples the network 100 can be a Fifth Generation (or New Radio, NR) Radio Access network (NG-RAN). The NG-RAN consists of gNodeBs (gNBs) 120, providing the user plane and control plane (RRC) protocol terminations towards the UE 110. The gNBs 120 are interconnected with each other by means of a network interface such as an X2 / Xn interface 126. The gNBs 120 are also connected by means of the NG interface 128 to core network nodes 130 such as the Access and Mobility management Function (AMF).

[0093] In some examples the network 100 can be an Evolved Universal Terrestrial Radio Access network (E-UTRAN). The E-UTRAN consists of E-UTRAN NodeBs (eNBs) 120, providing the E-UTRA user plane and control plane (RRC) protocol terminations towards the UE 110. The eNBs 120 can be interconnected with each other by means of an X2 interface 126. The eNBs can also be connected by means of the S1 interface to the Mobility Management Entity (MME).

[0094] Other types of networks can be used in other examples of the disclosure.

[0095] In networks 100 such as the network of Fig. 1 initial access procedures can be used to enable UEs 110 to connect to the gNBs 120 or other network entities for the first time or after a period of inactivity. The initial access procedure can comprise a random access procedure or any other suitable type of procedure.

[0096] The random access procedure can be contention based or contention free. In a contention based random access procedure the UE 110 is allowed to select a random access preamble from a pool of preambles shared with other UEs 110. This UE 110 therefore could select the same preamble as another UE which would result in contention. In a contention free random access procedure the gNB 120 allocates a dedicated random access preamble to a UE 110 which removes the risk of contention.

[0097] Fig. 2A shows an example access procedure. In this example the access procedure is a four-step random access procedure.

[0098] At block 200 (msg1) the UE 110 sends a specific preamble to the gNB 120. The preamble is sent via physical random-access channel (PRACH) using a specific resource called RACH (Random Access Channel) occasion (RO).

[0099] Following the transmission of the preamble the UE 110 starts a timer and waits for msg2 from the gNB 120. The UE 110 monitors the type- 1 physical downlink control channel (PDCCH) for the downlink control information (DCI).

[0100] At block 202 (msg2) the gNB 120 replies with a random access response (RAR) message. The RAR message comprises the uplink resource allocation for msg3. The RAR message comprises the detected preamble ID, the timing advance (TA) command, a temporary cell - radio network temporary identifier (C-RNTI), and uplink (UL) grant for the transmission of Msg3 on physical uplink shared channel (PLISCH).

[0101] In Fig. 2A msg2 is shown as a single message but can comprise multiple parts. For example a first message comprising the DCI can be sent in a first message on the PDCCH and a second message comprising the uplink resource allocation for msg3 can be sent on the physical downlink shared channel (PDSCH).

[0102] The RAR can comprise medium access control (MAC) packet data units (PDlls). An example of a MAC PDU 210 is shown in Fig. 2B. The MAC PDU 210 comprises a MAC subheader 212 and a MAC RAR 214.

[0103] The MAC subheader 212 comprises a random access preamble identity (RAPID) 216, a type field 218, and an extension field 220. The RAPID 216 identifies the preamble, the type field 218 indicates if the MAC subheader 212 comprises a RAPID or other type of information, the extension field 220 indicates if there are any following MAC PDUs.

[0104] The MAC RAR 214 comprises a TA command 222. A UL grant 224 and a temporary C-RNTI 226. The UL grant 224 comprises the resources that the UE 110 can use to send msg3.

[0105] Returning to Fig. 2A, at block 204 (msg3) the UE 110 sends an RRC connection request to the gNB 120. Msg3 comprises contention resolution identity (CRI). The UE 110 also starts the ra-contentionResolutionTimer and monitors for reception of contention resolution from the gNB 210.

[0106] When the gNB 120 receives msg3 the gNB 120 uses the UE identity in the msg3 to identify the UE 110 and schedules the sending of msg4.

[0107] At block 206 (msg4) the gNB sends contention resolution to the UE 110. Msg4 comprises data for contention resolution. Msg4 comprise the identity of the UE 110 and confirms that the gNB 120 has correctly identified the UE 110 and that contention has been resolved. Msg4 can comprise C-RNTI for the UE 110. Fig. 2C shows another example access procedure. In this example access procedure is a two-step random access procedure. This is similar to the four-step procedure but msg1 and msg3 are combined in msgA and sent without waiting for a response in between (which would be msg2 in the four-step procedure). MsgA is sent from the UE 110 to the gNB 120. Similarly msg2 and msg4 are combined into msgB which is sent from the gNB 120 to the UE 110.

[0108] In networks 100 such as the network 100 of Fig. 1 a UE 110 can operate in a single transmission / reception point (TRP) mode or multi-TRP mode. In some examples, a single cell 122 can comprise a single TRP or multiple TRPs. TRPS within the same cell 122 have a common SS (synchronization signal) / physical broadcast channel (PBCH) block which is specific to the cell 122. In multi-TRP operation, a serving cell can schedule the UE 110 from multiple TRPs. This can provide improved coverage, reliability and / or data rates for PDSCH, PDCCH, PUSCH, physical uplink control channel (PUCCH).

[0109] Two different operation modes can be used to schedule multi-TRP PDSCH transmissions: single-DCI and multi-DCI. For both modes, control of uplink and downlink operation can be done by physical layer and MAC layer, within the configuration provided by the radio resource control (RRC) layer. In single-DCI mode, only one TRP is responsible for the transmission of control data (PDCCH) to the UE 110. As a result, the UE 110 is scheduled by the same PDCCH containing a DCI for both TRPs. In multi-DCI mode two TRPs are responsible for the transmission of control data to the UE 110. As a result, the UE 110 is scheduled by independent DCIs from each TRP. In this case, if there is any problem in the radio link with one of the TRPs, the communication via other TRP can be intact.

[0110] In addition, there are two different operation modes for single DCI multi-TRP PDCCH. The different modes can enhance coverage and robustness. The first mode is PDCCH repetition and the second is single frequency network (SFN) based PDCCH transmission. In both modes, the UE 110 can receive two PDCCH transmissions, one from each TRP, carrying the same DCI. In PDCCH repetition mode, the gNB 120 will transmit and the UE 110 may receive the two PDCCH transmissions carrying the same DCI from two linked search spaces each associated with a different control resource set (CORESET). In SFN based PDCCH transmission mode, the gNB 120 transmits and the UE 110 can receive the two PDCCH transmissions carrying the same DCI from a single search space / CORESET using different TCI states.

[0111] The use of multi-TRPs can help to provide higher connection density, enhanced user experience, higher peak data throughput as well as lower latency in networks 100. To make use of the multi-TRPs a user equipment (UE) must be configured for multi-TRP operation during an access procedure. The access procedures shown in Figs. 2A to 2C enable a UE 110 to be synchronized in the uplink to a single TRP. To enable multi- TRP operation the UE 110 must first perform random access to a single TRP (using a procedure as outlined in Figs. 2A to 2C). Following the initial access procedure further steps are performed in which the UE 110 is reconfigured for multi-TRP operation. This involves additional RRC signaling overhead which slows down the start of multi-TRP operation. The examples of the disclosure provide procedures that enables a UE 110 to connect to multiple TRPs during an access procedure.

[0112] Fig. 3 shows example collocated network entities that can be used in examples of the disclosure. The collocated network entities can comprise different TRPS that are provided by the same gNB 120. The first TRP can provide coverage at a first frequency range and the second TRP can provide coverage at a second frequency range. The second frequency range can be different to the first frequency range. For example, the first frequency range can be FR1 and the second frequency range can be FR2.

[0113] The first dashed line 300 in Fig. 3 indicates the coverage provided by the first TRP at the first frequency range and the second dashed line 302 indicates the coverage provided by the second TRP at the second frequency range. The coverage for each frequency range is similar but not identical.

[0114] Because the network entities are collocated the timing advance for the first TRP and the second TRP will be the same because the signal from the respective TRPS to the UE 110 experiences the same multi-path propagation. Figs. 4A and 4B show example methods that can be used to implement examples of the disclosure. The method shown in Fig. 4A could be implemented by a UE 110 and the method shown in Fig. 4B could be implemented by a corresponding gNB 120 or other network entity.

[0115] At block 400 the UE 110 receives an indication of multiple frequency layers that can be used in an initial access procedure with multiple network entities. The multiple network entities can be collocated. The multiple network entities can comprise multiple TRPS or any other suitable network entities.

[0116] The indication of the multiple frequency layers can be received in a system information block (SIB) such as SIB1.

[0117] At block 402 the UE 110 sends a message to a first network entity of the multiple network entities. The UE 110 can select the first network entity from the multiple network entities based on measurements. For example, the UE 110 can select the first network entity based on the synchronized signal block (SSB) beam with the highest reference signal received power (RSRP).

[0118] The message can comprise a preamble and / or any other suitable information. The message can comprise msg1 in a four-step random access procedure or msgA in a two-step random access procedure, or any other suitable message.

[0119] At block 404 the UE 110 receives a response from the first network entity. The response indicates a TA that is valid for the first network entity and at least one second entity of the multiple network entities.

[0120] The response from the first network entity can also comprise a UL grant that is valid for the first network entity. In some examples the response from the first network entity can also comprise a UL grant that is valid for the second network entity. The UL grant can indicate the resources related to the relevant network entity that are to be used during the initial access procedure. The response can be msg2 in a four-step random access procedure or msgB in a two- step random access procedure, or any other suitable message.

[0121] At block 406 the UE 110 connects to the first network entity and the at least one second entity based, at least in part, on the received response. That is, the information such as the TA and UL grant can be used to connect to the first network entity and the second network entity. The process of the connection to the first network entity and the at least one second entity can depend upon the network configuration and any other relevant factors.

[0122] In some examples connecting to the first network entity and the at least one second network entity comprises the UE 110 sending an identity of the UE 110 and an indication that the UE 110 prefers operation with multiple network entities to the first network entity. If there are more than two network entities available the UE 110 can also indicate the preferred network entities.

[0123] The identity of the UE 110 and the indication that the UE 110 prefers operation with multiple network entities can be sent in any suitable signaling. In some examples the indication can be provided in an RRCSetupRequest. The RRCSetupRequest can be sent in msg3 of a four-step random access procedure or in msgA of a two-step random access procedure, or in any other suitable messages.

[0124] In some examples connecting to the first network entity and the at least one second network entity comprises the UE 110 receiving a response to the indication that the UE prefers operation with multiple network entities. The response to the indication can comprise connection information of the first network entity and the at least one second network entity. The response to the indication can be received from the first network entity. That is, the first network entity can provide connection information for multiple network entities.

[0125] The connection information that is received from the first network entity can comprise contention resolution, downlink control information, radio resource control setup, and / or any other suitable information. The connection information can be received in msg4 of a four-step random access procedure, msgB of a two-step random access procedure, or any other suitable messages.

[0126] Other information can also be provided with the connection information in some examples. For example, if there are more than two network entities that can used for operation with multiple network entities then the network entity can request the UE to provide an indication or selection of the network entities that it is to be connected to.

[0127] Variations to the example of Fig. 4A could be used in some examples. For instance, in some examples, the indication of the multiple frequency layers can comprise additional information such as an indication of multiple modes of operation for which the multiple frequency layers can be used. The different modes of operations can comprise one or more of carrier aggregation, multi-TRP operation, dual connectivity, multi carrier single cell, or any other suitable mode of operation. In such examples the response message that is sent by the UE can indicate the preferred mode of operation.

[0128] In some examples, at block 400, the UE could receive an indication of carriers / frequencies available for carrier aggregation that can be used in an initial access procedure with multiple network entities wherein the multiple network entities have a common timing advance. In such examples the first network entity can comprise a primary cell and the second network entity can comprise a secondary cell.

[0129] In examples where the UE receives an indication of carriers / frequencies available for carrier aggregation connecting to the first network entity and the at least one second network entity the method can comprise can comprise the UE 110 sending an identity of the UE 110 and an indication that the UE 110 prefers operation with carrier aggregation to the first network entity. This indication can be sent in any suitable signaling such as an RRCSetupRequest as described above. The identity of the UE 110 can be used by the network entity for contention resolution and / or for any other suitable purpose. Fig. 4B shows a method that can be implemented by a network entity. The network entity could be a first network entity that is in communication with a UE 110 that performs the method of Fig. 4A.

[0130] At block 410 the network entity sends, to a UE 110, an indication of multiple frequency layers that can be used in an initial access procedure with the network entity and at least one other network entity. In some examples the multiple frequency layers can be used with the entity and at least one other network entity. In some examples the multiple frequency layers can be used with more than two network entities. The multiple network entities can be collocated. The multiple network entities can comprise multiple TRPS or any other suitable network entities.

[0131] The indication of the multiple frequency layers can be sent in a system information block (SIB) such as SIB1.

[0132] At block 412 the network entity receives a message from the UE 110. The message can comprise a preamble and / or any other suitable information. The message can comprise msg1 in a four-step random access procedure or msgA in a two-step random access procedure, or any other suitable message.

[0133] At block 414 the network entity sends a response to the UE 110 indicating a timing advance that is valid for the network entity and the at least one other network entity. The response indicates a TA that is valid for the network entity and the at least one other network entity of the multiple network entities.

[0134] The response can also comprise a UL grant that is valid for the network entity. In some examples the response from the network entity can also comprise a UL grant that is valid for the at least one network entity The UL grant can indicate the resources related to relevant network entity that are to be used during the initial access procedure.

[0135] In order to send a response indicating a UL grant that is valid for the at least one network entity the network entity has to obtain the information relating to the at least one other network entity. This information can be obtained via an Xn interface or an NG interface or any other suitable type of interface. In some examples the respective network entities can be comprised within the same distributed unit (DU) and so the information is available to the network entity.

[0136] At block 416 the network entity enables the UE 110 to connect to the network entity and the at least one other network entity based, at least in part, on the sent response. That is, the information such as the TA can be used to connect to the network entity and the at least one other network entity. The process of the connection to the network entity and the at least one at least one other entity can depend upon the network configuration and any other relevant factors.

[0137] In some examples enabling connecting to the network entity and the at least one other network entity comprises the network entity receiving an identity of the UE 110 and an indication that the UE 110 prefers operation with multiple network entities from the UE 110. If there are more than two network entities available the UE 110 can also indicate the preferred network entities.

[0138] The identity of the UE 110 and the indication that the UE 110 prefers operation with multiple network entities can be sent in any suitable signaling. In some examples the indication can be provided in an RRCSetupRequest. The RRCSetupRequest can be sent in msg3 of a four-step random access procedure or in msgA of a two-step random access procedure, or in any other suitable messages.

[0139] In some examples connecting to the network entity and the at least one other network entity comprises the UE 110 receiving a response to the indication that the UE prefers operation with multiple network entities. The response to the indication can comprise connection information of the network entity and the at least one other network entity. The network entity can provide connection information for multiple network entities.

[0140] The connection information that is sent to the UE 110 by the network entity can comprise contention resolution, downlink control information, radio resource control setup, and / or any other suitable information. The connection information can be sent in msg4 of a four-step random access procedure, msgB of a two-step random access procedure, or any other suitable messages.

[0141] Variations to the example of Fig. 4B could be used in some examples. For instance, in some examples, the indication of the multiple frequency layers can comprise additional information such as an indication of multiple modes of operation for which the multiple frequency layers can be used. The different modes of operations can comprise one or more of carrier aggregation, multi-TRP operation, dual connectivity, multi carrier single cell, or any other suitable mode of operation. In such examples the response message that is received from the UE can indicate the preferred mode of operation.

[0142] In some examples, at block 410, the network entity could send an indication of carriers / frequencies available for carrier aggregation that can be used in an initial access procedure with multiple network entities wherein the multiple network entities have a common timing advance. In such examples the first network entity can comprise a primary cell and the second network entity can comprise a secondary cell.

[0143] In examples where the network entity sends an indication of carriers / frequencies available for carrier aggregation connecting to the first network entity and the at least one second network entity the method can comprise the network entity receiving an identity of the UE 110 and an indication that the UE 110 prefers operation with carrier aggregation to the second network entity. This indication can be sent in any suitable signaling such as an RRCSetupRequest as described above.

[0144] Fig. 5A shows an example access procedure. The access procedure could implement the methods of Figs. 4A and 4B or any suitable variations of these methods. In the example of Fig. 5 the UE 110 connects to two network entities. In other examples the UE 110 could connect to more than two network entities.

[0145] In the example of Fig. 5 the first network entity 500_P comprises a primary TRP (p- TRP) and the second network entity 500_S comprises a secondary TRP (s-TRP). Other types of network entities could be used in other examples such as a primary cell and a secondary cell used for carrier aggregation. The respective network entities 500_P, 500_S are collocated and have the same TA. The respective network entities 500_P, 500_S can be provided within a gNB 120 or any other suitable entity.

[0146] Before the method of Fig. 5 is implemented the UE 110 is downlink synchronized with the network.

[0147] At block 502 the first network entity 500_P broadcasts signaling information. The signaling information can be broadcast using SIB1 or any other suitable signaling. The UE 110 reads the system information from the signaling information. The system information can comprise information that is used by the UE 110 to perform initial access.

[0148] In examples of the disclosure the signaling information that is broadcast by the first network entity 500_P comprises an indication of multiple frequency layers that can be used in the same initial access procedure with multiple network entities. The multiple frequencies and multiple network entities can be used by the UE 110 for multi-TRP operations.

[0149] At block 504 the UE 110 sends mgs1 to the first network entity 500_P. In some examples the UE 110 can select which network entity to send msg1 to. The selection can be made from the multiple network entities that have been indicated in SIB1. The UE 110 can select the network entity by selecting the SSB beam with the highest RSRP amongst those it can find and measure.

[0150] The UE 110 also selects a preamble. The preamble is transmitted the first network entity 500_P in msg1.

[0151] The first network entity 500_P responds to msg1 and sends a response to the UE 110. At block 506 the first network entity 500_P sends DCI on PDCCH to the UE 110 and at block 508 the first network entity 500_P sends msg2 to the UE 110. Msg2 comprises the TA command that is valid for both the first network entity 500_P and the second network entity 500_S. As the network entities 500_P, 500_S are collocated the TA is the same for both network entities 500_P, 500_S. This is also indicated in SIB1 when the frequency layers that can be used in the same access procedure is indicated.

[0152] Msg2 can also comprise other information such as a UL grant valid for the first network entity 500_P.

[0153] Following the receipt of msg2 the UE 110 can connect to the network entities 500_P, 500_S. To connect to the network entities 500_P, 500_S the UE 110, at block 510 sends msg3 to the first network entity 500_P. Msg3 comprises the identity of the UE 110 and an RRCSetupRequest. The RRCSetupRequest provides an indication that the UE 110 would prefer multi TRP operation. The UE 110 knows that multi TRP operation is available because this is indicated in SIB1 by the indication of the multiple frequency layers that can be used in the same access procedure.

[0154] Following the receipt of msg3 the first network entity 500_P sends connection information for at least the first network entity 500_P to the UE 110. At block 512, the first network entity 500_P sends DCI on PDCCH to the UE 110 and at block 514 the first network entity 500_P performs content resolution by sending msg4 comprising C- RNTI and UL grant. At block 516 the first network entity 500_P sends msg4 comprising RRCSetup.

[0155] At block 518 the UE 110 acknowledges receipt of the RRCSetup message by sending a HARQ ACK signal. At block 520 the UE 110 sends an the RRCSetupComplete. The RRCSetupComplete can comprise the capabilities of the UE 110 for multi-TRP operation. For instance, it can indicate which type of modes of multi-TRP operation could be used by the UE 110. The different types of multi-TRP operation could comprise single-DCI, multi-DCI, PDCCH repetition mode, SFN based PDCCH transmission mode, or any other suitable modes.

[0156] At block 522 the first network entity 500_P configures the UE 110 for multi-TRP operation by sending an RRC configuration signal. At block 524 the UE 110 sends an RRC configuration complete signal to the first network entity 500_P. At block 526 the UE 110 is in RRC_CONNECTED mode. As soon as the access procedure is completed the UE is in RRC CONNECTED state with multi-TRP operation as shown at block 528.

[0157] The example method of Fig. 5 is implemented using a four-step random access procedure. In other examples other types of initial access procedure could be used, such as a two-step random access procedure, and the method can be adapted accordingly.

[0158] The access procedure could also comprise blocks that are not shown in Fig. 5 such as non-access stratum registration and / or any other suitable blocks.

[0159] Fig. 5B shows another example access procedure. The access procedure is similar to that shown in Fig. 5A and corresponding reference numerals are used for corresponding features.

[0160] The procedure shown in Fig. 5B differs from the one shown in Fig. 5A in that, at block 502_B the SIB1 can comprise additional information. For example, The SIB1 can comprise an indication of multiple modes of operation for which multiple frequency layers can be used. The different modes of operation can comprise, carrier aggregation, multi-TRP operation, dual connectivity, or any other mode of operation. An indication of multiple modes of operation for which multiple frequency layers can be used could be sent using other types of signaling in other examples of the disclosure.

[0161] The procedure shown in Fig. 5B differs from the one shown in Fig. 5A in that, at block 510_B the message sent from the UE 110 to the pTRP can also comprise an indication of a preferred mode of operation. This preferred mode of operation can be selected from the available modes of operation that are indicated in the SI B_1 .

[0162] At block 516_B the first network entity 500_P sends msg4 comprising RRCSetup. In the example of Fig. 5B this message can also comprise a request for the UE capabilities of the selected mode of operation. The UE 110 can provide the relevenat capabilities for the selected mode of operation in the RRCSetupComplete sent at block 520_B, or in any other suitable signaling. Once the access procedure is completed the UE is in RRC CONNECTED state with the selected mode of operation as shown at block 528_B.

[0163] Fig. 6 shows another example access procedure. The access procedure could implement the methods of Figs. 4A to 4B or any suitable variations of these methods. In the example of Fig. 6 the UE 110 connects to two network entities. In other examples the UE 110 could connect to more than two network entities.

[0164] In the example of Fig. 6 the first network entity 500_P comprises a primary TRP (p- TRP) and the second network entity 500_S comprises a secondary TRP (s-TRP). Other types of network entities could be used in other examples such as a primary cell and a secondary cell used for carrier aggregation. The respective network entities 500_P, 500_S are collocated and have the same TA. The respective network entities 500_P, 500_S can be provided within a gNB 120 or any other suitable entity.

[0165] Before the method of Fig. 6 is implemented the UE 110 is downlink synchronized with the network.

[0166] At block 600 the first network entity 500_P broadcasts signaling information. The signaling information can be broadcast using SIB1 or any other suitable signaling. The UE 110 reads the system information from the signaling information. The system information can comprise information that is used by the UE 110 to perform initial access.

[0167] In examples of the disclosure the signaling information that is broadcast by the first network entity 500_P comprises an indication of multiple frequency layers that can be used in the same initial access procedure with multiple network entities. The multiple frequencies and multiple network entities can be used by the UE 110 for multi-TRP operations.

[0168] At block 602 the UE 110 sends mgs1 to the first network entity 500_P. In some examples the UE 110 can select which network entity to send msg1 to. The selection can be made from the multiple network entities that have been indicated in SIB1. The UE 110 can select the network entity by selecting the SSB beam with the highest RSRP amongst those it can find and measure.

[0169] The UE 110 also selects a preamble. The preamble is transmitted the first network entity 500_P in msg1.

[0170] The first network entity 500_P responds to msg1 and sends a response to the UE 110. At block 604 the first network entity 500_P sends DCI on PDCCH to the UE 110. At block 606 the first network entity 500_P sends msg2 to the UE 110.

[0171] The msg2s received from multiple network entities 500_P, 500_S comprises a TA command. The TA command is valid for both the first network entity 500_P and the second network entity 500_S. As the network entities 500_P, 500_S are collocated the TA is the same for both network entities 500_P, 500_S.

[0172] Msg2 can also comprise other information such as a UL grant valid for the respective network entity 500_P. In this case msg2 can also comprise a UL grant valid for the second network entity 500_S. The first network entity 500_P can obtain the information relating to the UL grant for the second network entity 500_S via the Xn interface or via the NG interface or because the first network entity 500_P and the second network entity 500_S are part of the same DU.

[0173] Following the receipt of msg2 the UE 110 can connect to the network entities 500_P, 500_S. To connect to the network entities 500_P, 500_S the UE 110, at block 608 sends msg3 to the first network entity 500_P and at block 610 the UE 110 sends msg3 to the second network entity 500_S. That is, the UE 110 sends multiple msg3s, or other connection requests, to multiple network entities 500_P, 500_S. The UE 110 can use information received from first network entity 500_P to send msg3 to one or more second network entities 500_S.

[0174] The respective msg3s can comprise the identity of the UE 110 and an RRCSetupRequest. The RRCSetupRequest provides an indication that the UE 110 would prefer multi TRP operation. The UE 110 knows that multi TRP operation is available because this is indicated in SIB1 by the indication of the multiple frequency layers that can be used in the same access procedure. The sending of the msg3 to multiple network entities can act as the indication that the UE 110 prefers operation with multiple network entities. The sending of the msg3 to multiple network entities can act as the indication of the TRPs with which the UE 110 would like to operate in multi-TRP mode.

[0175] Following the receipt of msg3 the first network entity 500_P sends connection information for at least the first network entity 500_P to the UE 110. At block 612, the first network entity 500_P sends DCI on PDCCH to the UE 110 and at block 614 the first network entity 500_P performs content resolution by sending msg4 comprising C- RNTI and UL grant. At block 616 the first network entity 500_P sends msg4 comprising RRCSetup.

[0176] At block 618 the UE 110 acknowledges receipt of the RRCSetup message by sending a HARQ ACK signal. At block 620 the UE 110 sends an the RRCSetupComplete. The RRCSetupComplete can comprise the capabilities of the UE 110 for multi-TRP operation. For instance, it can indicate which type of modes of multi-TRP operation could be used by the UE 110. The different types of multi-TRP operation could comprise single-DCI, multi-DCI, PDCCH repetition mode, SFN based PDCCH transmission mode, or any other suitable modes.

[0177] At block 622 the first network entity 500_P configures the UE 110 for multi-TRP operation by sending an RRC configuration signal. At block 624 the UE 110 sends an RRC configuration complete signal to the first network entity 500_P. At block 626 the UE 110 is in RRC_CONNECTED mode. As soon as the access procedure is completed the UE is in RRC CONNECTED state with multi-TRP operation as shown at block 628.

[0178] The example method of Fig. 6 is implemented using a four-step random access procedure. In other examples other types of initial access procedure could be used, such as a two-step random access procedure, and the method can be adapted accordingly. The access procedure could also comprise blocks that are not shown in Fig. 6 such as non-access stratum registration and / or any other suitable blocks.

[0179] Figs. 7A to 7C show example methods that can be used to implement examples of the disclosure. The method shown in Fig. 7A could be implemented by a UE 110 and the method shown in Fig. 7B could be implemented by first network entity and the method shown in Fig. 7C could be implemented in a second network entity.

[0180] At block 700 the UE 110 receives an indication of multiple frequency layers that can be used in an initial access procedure with multiple network entities. The multiple network entities can be collocated. The multiple network entities can comprise multiple TRPS or any other suitable network entities.

[0181] The indication of the multiple frequency layers can be received in a system information block (SIB) such as SIB1.

[0182] At block 702 the UE 110 sends a message to a first network entity and at least one second network entity of the multiple network entities. The UE 110 can select the first network entity from the multiple network entities based on measurements. For example, the UE 110 can select the first network entity based on the synchronized signal block (SSB) beam with the highest reference signal received power (RSRP).

[0183] The message can comprise a preamble and / or any other suitable information. The message can comprise msg1 in a four-step random access procedure or msgA in a two-step random access procedure, or any other suitable message.

[0184] At block 704 the UE 110 receives a response from the first network entity and also the second network entity of the multiple network entities. The response from the first network entity indicates a TA that is valid for the first network entity and the response from the second entity indicates a TA that is valid for the second network entity. The same TA can be valid for both of the network entities.

[0185] The response from the first network entity can also comprise a UL grant that is valid for the first network entity. The UL grant for the first network entity can indicate the resources related to the first network entity that are to be used during the initial access procedure. Similarly the response from the second network entity can also comprise a UL grant that is valid for the second network entity. The UL grant for the second network entity can indicate the resources related to the second network entity that are to be used during the initial access procedure.

[0186] The response can be msg2 in a four-step random access procedure or msgB in a two- step random access procedure, or any other suitable message.

[0187] At block 706 the UE 110 connects to the first network entity and the at least one second entity based, at least in part, on the received response. That is, the information such as the TA can be used to connect to the first network entity and the second network entity. The process of the connection to the first network entity and the at least one second entity can depend upon the network configuration and any other relevant factors.

[0188] In some examples connecting to the first network entity and the at least one second network entity comprises the UE 110 sending an identity of the UE 110 and an indication that the UE 110 prefers operation with multiple network entities to the first network entity and also to the second network entity. If there are more than two network entities available the UE 110 can also send the identity of the UE 110 and an indication that the UE 110 prefers operation with multiple network entities to more than two network entities.

[0189] In some examples the sending of the identity of the UE 110 to multiple network entities acts as the indication that the UE 110 prefers operation with multiple network entities. The network is aware of which network entities the UE 110 sends the identity to and can use this to infer that the UE 110 prefers operation with multiple network entities. If there are more than two network entities available then the UE 110 can select which of the network entities they want to use for the operation with multiple network entities by sending the identity to the selected network entities.

[0190] The identity of the UE 110 and / or the indication that the UE 110 prefers operation with multiple network entities can be sent in any suitable signaling. In some examples the indication can be provided in an RRCSetupRequest. The RRCSetupRequest can be sent in msg3 of a four-step random access procedure or in msgA of a two-step random access procedure, or in any other suitable messages.

[0191] In some examples connecting to the first network entity and the at least one second network entity comprises the UE 110 receiving a response to the indication that the UE prefers operation with multiple network entities. The response to the indication can comprise connection information of the first network entity and the at least one second network entity. The response to the indication can be received from the first network entity. That is, the first network entity can provide connection information for multiple network entities.

[0192] The connection information that is received from the first network entity can comprise contention resolution, downlink control information, radio resource control setup, and / or any other suitable information.

[0193] The connection information can be received in msg4 of a four-step random access procedure, msgB of a two-step random access procedure, or any other suitable messages.

[0194] Fig. 7B shows a method that can be implemented by a network entity. The network entity could be a first network entity that is in communication with a UE 110 that performs the method of Fig. 7A.

[0195] At block 710 the network entity sends, to a UE 110, an indication of multiple frequency layers that can be used in an initial access procedure with the network entity and at least one other network entity. In some examples the multiple frequency layers can be used with the entity and at least one other network entity. In some examples the multiple frequency layers can be used with more than two network entities. The multiple network entities can be collocated. The multiple network entities can comprise multiple TRPS or any other suitable network entities.

[0196] The indication of the multiple frequency layers can be sent in a system information block (SIB) such as SIB1. At block 712 the network entity receives a message from the UE 110. The message can comprise a preamble and / or any other suitable information. The message can comprise msg1 in a four-step random access procedure or msgA in a two-step random access procedure, or any other suitable message.

[0197] At block 714 the network entity sends a response to the UE 110 indicating a TA that is valid for the network entity. The response can also comprise a UL grant that is valid for the network entity. The UL grant can indicate the resources related to the network entity that are to be used during the initial access procedure.

[0198] At block 716 the network entity enables the UE 110 to connect to the network entity and the at least one other network entity based, at least in part, on the sent response. That is, the information such as the TA can be used to connect to the network entity and the at least one other network entity. The process of the connection to the network entity and the at least one at least one other entity can depend upon the network configuration and any other relevant factors.

[0199] In some examples enabling connecting to the network entity and the at least one other network entity comprises the network entity receiving an identity of the UE 110 and an indication that the UE 110 prefers operation with multiple network entities from the UE 110. If there are more than two network entities available the UE 110 can also indicate the preferred network entities. The UE 110 can indicate the preferred network entities by sending the identity of the UE 110 to the respective network entities.

[0200] The identity of the UE 110 and the indication that the UE 110 prefers operation with multiple network entities can be sent in any suitable signaling. In some examples the indication can be provided in an RRCSetupRequest. The RRCSetupRequest can be sent in msg3 of a four-step random access procedure or in msgA of a two-step random access procedure, or in any other suitable messages.

[0201] In some examples connecting to the network entity and the at least one other network entity comprises the UE 110 receiving a response to the indication that the UE prefers operation with multiple network entities. The response to the indication can comprise connection information of the network entity and the at least one other network entity.

[0202] The network entity can provide connection information for multiple network entities.

[0203] The connection information that is sent to the UE 110 by the network entity can comprise contention resolution, downlink control information, radio resource control setup, and / or any other suitable information.

[0204] The connection information can be sent in msg4 of a four-step random access procedure, msgB of a two-step random access procedure, or any other suitable messages.

[0205] Fig. 7C shows another method that can be implemented by a network entity. In this example network entity could be a second network entity that is to be connected to a UE 110 that performs the method of Fig. 7A.

[0206] At block 720 the network entity receives a message from the UE 110. The message can comprise a preamble and / or any other suitable information. The message can comprise msg1 in a four-step random access procedure or msgA in a two-step random access procedure, or any other suitable message.

[0207] At block 722 the second network entity sends a message to a UE 110 indicating a timing advance that is valid for the network entity. The message can also comprise a UL grant that is valid for the second network entity. The UL grant can indicate the resources related to the second network entity that are to be used during the initial access procedure.

[0208] At block 724 the second network entity enables the UE 110 to connect to the second network entity and the at least one other network entity based, at least in part, on the message sent at block 722. The process of the connection to the network entity and the at least one at least one other entity can depend upon the network configuration and any other relevant factors. Enabling the UE 110 to connect to the network entity and at least one other network entity comprises receiving an identity of the UE 110 and an indication that the UE 110 prefers operation with multiple network entities.

[0209] The identity of the UE 110 and the indication that the UE 110 prefers operation with multiple network entities can be sent in any suitable signaling. In some examples the indication can be provided in an RRCSetupRequest. The RRCSetupRequest can be sent in msg3 of a four-step random access procedure or in msgA of a two-step random access procedure, or in any other suitable messages.

[0210] Fig. 8 shows another example access procedure. The access procedure could implement the methods of Figs. 7A to 7C or any suitable variations of these methods. In the example of Fig. 8 the UE 110 connects to two network entities. In other examples the UE 110 could connect to more than two network entities.

[0211] In the example of Fig. 8 the first network entity 500_P comprises a primary TRP (p- TRP) and the second network entity 500_S comprises a secondary TRP (s-TRP). Other types of network entities could be used in other examples such as a primary cell and a secondary cell used for carrier aggregation. The respective network entities 500_P, 500_S are collocated and have the same TA. The respective network entities 500_P, 500_S can be provided within a gNB 120 or any other suitable entity.

[0212] Before the method of Fig. Sis implemented the UE 110 is downlink synchronized with the network.

[0213] At block 800 the first network entity 500_P broadcasts signaling information. The signaling information can be broadcast using SIB1 or any other suitable signaling. The UE 110 reads the system information from the signaling information. The system information can comprise information that is used by the UE 110 to perform initial access.

[0214] In examples of the disclosure the signaling information that is broadcast by the first network entity 500_P comprises an indication of multiple frequency layers that can be used in the same initial access procedure with multiple network entities. The multiple frequencies and multiple network entities can be used by the UE 110 for multi-TRP operations.

[0215] At block 802 the UE 110 sends mgs1 to the first network entity 500_P. In this example the UE 110 also sends, at block 804, msg1 to the second network entity 500_S. In some examples the UE 110 can select which network entities to send msg1 to. The selection can be made from the multiple network entities that have been indicated in SIB1. The UE 110 can select the network entities by selecting the SSB beam with the highest RSRP amongst those it can find and measure.

[0216] The UE 110 also selects a preamble. The preamble is transmitted the first network entity 500_P and the second network entity 500_S in respective msg 1s.

[0217] The first network entity 500_P responds to msg1 and sends a response to the UE 110. At block 806 the first network entity 500_P sends DCI on PDCCH to the UE 110. At block 808 the first network entity 500_P sends msg2 to the UE 110 and at block 810 the second network entity 500_S also sends msg2 to the UE 110. The UE 110 therefore receives multiple msg2s from multiple network entities 500_P, 500_S.

[0218] The msg2s received from multiple network entities 500_P, 500_S comprises a TA command. The TA command is valid for both the first network entity 500_P and the second network entity 500_S. As the network entities 500_P, 500_S are collocated the TA is the same for both network entities 500_P, 500_S.

[0219] Msg2 can also comprise other information such as a UL grant valid for the respective network entity 500_P.

[0220] Following the receipt of msg2 the UE 110 can connect to the network entities 500_P, 500_S. To connect to the network entities 500_P, 500_S the UE 110, at block 812 sends msg3 to the first network entity 500_P and at block 814 the UE 110 sends msg3 to the second network entity 500_S. That is, the UE 110 sends multiple msg3s, or other connection requests, to multiple network entities 500_P, 500_S.

[0221] The respective msg3s can comprise the identity of the UE 110 and an RRCSetupRequest. The RRCSetupRequest provides an indication that the UE 110 would prefer multi TRP operation. The UE 110 knows that multi TRP operation is available because this is indicated in SIB1 by the indication of the multiple frequency layers that can be used in the same access procedure. The sending of the msg3 to multiple network entities can act as the indication that the UE 110 prefers operation with multiple network entities. The sending of the msg3 to multiple network entities can act as the indication of the TRPs with which the UE 110 would like to operate in multi-TRP mode.

[0222] Following the receipt of msg3 the first network entity 500_P sends connection information for at least the first network entity 500_P to the UE 110. At block 816, the first network entity 500_P sends DCI on PDCCH to the UE 110 and at block 818 the first network entity 500_P performs content resolution by sending msg4 comprising C- RNTI and UL grant. At block 820 the first network entity 500_P sends msg4 comprising RRCSetup.

[0223] At block 822 the UE 110 acknowledges receipt of the RRCSetup message by sending a HARQ ACK signal. At block 824 the UE 110 sends an the RRCSetupComplete. The RRCSetupComplete can comprise the capabilities of the UE 110 for multi-TRP operation. For instance, it can indicate which type of modes of multi-TRP operation could be used by the UE 110. The different types of multi-TRP operation could comprise single-DCI, multi-DCI, PDCCH repetition mode, SFN based PDCCH transmission mode, or any other suitable modes.

[0224] At block 826 the first network entity 500_P configures the UE 110 for multi-TRP operation by sending an RRC configuration signal. At block 828 the UE 110 sends an RRC configuration complete signal to the first network entity 500_P. At block 830 the UE 110 is in RRC_CONNECTED mode. As soon as the access procedure is completed the UE is in RRC CONNECTED state with multi-TRP operation as shown at block 832.

[0225] The example method of Fig. 8 is implemented using a four-step random access procedure. In other examples other types of initial access procedure could be used, such as a two-step random access procedure, and the method can be adapted accordingly. The access procedure could also comprise blocks that are not shown in Fig. 6 such as non-access stratum registration and / or any other suitable blocks.

[0226] Fig. 9 shows an example controller 900. The controller 900 could be provided within an entity such as a network node 120 or a UE 110 any other suitable entity. Implementation of the controller 900 may be as controller circuitry. The controller 900 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).

[0227] As illustrated in Fig. 9, the controller 900 can be implemented using instructions that enable hardware functionality, for example, by using executable instructions of a computer program 906 in a general-purpose or special-purpose processor 902 that may be stored on a computer readable storage medium (disk, memory etc.) to be executed by such a processor 902.

[0228] The processor 902 is configured to read from and write to the memory 904. The processor 902 may also comprise an output interface via which data and / or commands are output by the processor 902 and an input interface via which data and / or commands are input to the processor 902.

[0229] The memory 904 stores a computer program 906 comprising computer program instructions (computer program code) that controls the operation of the apparatus when loaded into the processor 902. The computer program instructions, of the computer program 806, provide the logic and routines that enables the apparatus to perform the methods illustrated in the Figs. The processor 902 by reading the memory 904 is able to load and execute the computer program 906.

[0230] In some examples where the controller 900 is provided within a device such as a network entity 120 the controller 900 therefore comprises means for: sending, to a UE, an indication of multiple frequency layers that can be used in an initial access procedure with the network entity and at least one other network entity; receiving a message from the UE; sending a response to the UE indicating a timing advance that is valid for the network entity and the at least one other network entity; and enabling the UE to connect to the network entity and the at least one other network entity based, at least in part, on the sent response.

[0231] In some examples where the controller 900 is provided within a device such as a UE 110 the controller 900 therefore comprises means for: receiving an indication of multiple frequency layers that can be used in an initial access procedure with multiple network entities; sending a message to a first network entity of the multiple network entities; receiving a response from the first network entity indicating a timing advance that is valid for the first network entity and at least one second entity of the multiple network entities; and connecting to the first network entity and the at least one second entity based, at least in part, on the received response.

[0232] The computer program 906 may arrive at the apparatus via any suitable delivery mechanism 908. The delivery mechanism 908 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 906. The delivery mechanism may be a signal configured to reliably transfer the computer program 906. The apparatus may propagate or transmit the computer program 906 as a computer data signal.

[0233] The computer program 906 can comprise computer program instructions, which when executed by a network entity 120, cause the network entity 120 to perform at least the following or for performing at least the following: sending, to a UE, an indication of multiple frequency layers that can be used in an initial access procedure with the network entity and at least one other network entity; receiving a message from the UE; sending a response to the UE indicating a timing advance that is valid for the network entity and the at least one other network entity; and enabling the UE to connect to the network entity and the at least one other network entity based, at least in part, on the sent response.

[0234] The computer program 906 can comprise computer program instructions, which when executed by a UE 110, cause the UE 110 to perform at least the following or for performing at least the following: receiving an indication of multiple frequency layers that can be used in an initial access procedure with multiple network entities; sending a message to a first network entity of the multiple network entities; receiving a response from the first network entity indicating a timing advance that is valid for the first network entity and at least one second entity of the multiple network entities; and connecting to the first network entity and the at least one second entity based, at least in part, on the received response.

[0235] 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.

[0236] Although the memory 904 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.

[0237] Although the processor 902 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 902 may be a single core or multi-core processor.

[0238] 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.

[0239] As used in this application, the term “circuitry” can refer to one or more or all of the following:

[0240] (a) hardware-only circuitry implementations (such as implementations in only analog and / or digital circuitry) and

[0241] (b) combinations of hardware circuits and software, such as (as applicable):

[0242] (i) a combination of analog and / or digital hardware circuit(s) with software / firmware and

[0243] (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

[0244] (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.

[0245] 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.

[0246] The blocks illustrated in the Figs, can represent steps in a method and / or sections of code in the computer program 906. 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.

[0247] Where a structural feature has been described, it may be replaced by means for performing one or more of the functions of the structural feature whether that function or those functions are explicitly or implicitly described.

[0248] 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.

[0249] 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.

[0250] 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.’

[0251] 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.

[0252] 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.

[0253] 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.

[0254] 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.

[0255] 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.

[0256] Features described in the preceding description may be used in combinations other than the combinations explicitly described above.

[0257] Although functions have been described with reference to certain features, those functions may be performable by other features whether described or not.

[0258] 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.

[0259] Although features have been described with reference to certain examples, those features may also be present in other examples whether described or not.

[0260] 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.

[0261] 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.

[0262] 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.

[0263] 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.

[0264] 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

43CLAIMS1 . 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 to perform at least: receiving an indication of multiple frequency layers that can be used in an initial access procedure with multiple network entities; sending a message to a first network entity of the multiple network entities; receiving a response from the first network entity indicating a timing advance that is valid for the first network entity and at least one second entity of the multiple network entities; and connecting to the first network entity and the at least one second entity based, at least in part, on the received response.

2. The UE of any of claim 1 wherein the network entities comprise transmit / receive points (TRPs).

3. The UE of any preceding claims wherein the indication of multiple frequency layers is received in a system information block.

4. The UE of any preceding claims wherein the processor and the memory are arranged to select the first network entity from the multiple network entities based on measurements.

5. The UE of any preceding claims wherein the response from the first network entity comprises an uplink grant valid for the first network entity.

6. The UE of claim 5 wherein the response from the first network entity comprises an uplink grant valid for the second network entity.

7. The UE of any of claims 5 to 6 wherein the uplink grant indicates the resources related to the relevant network entity to be used by the UE during the initial access procedure.

448. The UE of any preceding claims wherein connecting to the first network entity and the at least one second network entity comprises sending an identity of the UE and an indication that the UE prefers operation with multiple network entities to the first network entity.

9. The UE of claim 8 wherein connecting to the first network entity and the at least one second network entity comprises sending an identity of the UE and an indication that the UE prefers operation with multiple network entities to the second network entity.

10. The UE of any of claims 8 to 9 wherein the indication that the UE prefers operation with multiple network entities is provided in an RRCSetupRequest wherein the RRCSetupRequest is sent in one of: msg3 of a four-step random access procedure; or msgA of a two-step random access procedure.11 . The UE of any of claims 8 to 10 wherein connecting to the first network entity and the at least one second network entity comprises receiving a response to the indication that the UE prefers operation with multiple network entities wherein the response to the indication comprises connection information of the first network entity and the at least one second network entity and the response to the indication is received from the first network entity.

12. The UE of claim 11 wherein the connection information comprises at least one of: contention resolution; downlink control information; radio resource control setup.

13. The UE of any of claims 11 to 12 wherein the connection information is received in one of: msg4 of a four-step random access procedure; or msgB of a two-step random access procedure.4514. The UE of any preceding claim wherein the indication of multiple frequency layers that can be used in an initial access procedure with multiple network entities also indicates multiple modes of operation for which the multiple frequency layers can be used.

15. The UE of claim 14 wherein the multiple modes of operation comprise one or more of: carrier aggregation; multi-TRP operation; dual connectivity; multi carrier single cell.

16. A network entity comprising: at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the network entity to perform at least: sending, to a UE, an indication of multiple frequency layers that can be used in an initial access procedure with the network entity and at least one other network entity; receiving a message from the UE; sending a response to the UE indicating a timing advance that is valid for the network entity and the at least one other network entity; and enabling the UE to connect to the network entity and the at least one other network entity based, at least in part, on the sent response.

17. The network entity of claim 16 wherein the response to the UE comprises an uplink grant valid for the at least one other network entity.

18. The network entity of claim 17 wherein the network entity obtains the uplink grant valid for the at least one other network entity via at least one of: an Xn interface; or an Ng interface.

19. The network entity of claim 18 wherein the network entity and the at least one other network entity are comprised within a distributed unit.

20. The network entity of any of claims 17 to 19 wherein the uplink grant indicates the resources related to the network entity to be used by the UE during the initial access procedure

Images