Setting up UE for initial RACH procedure

Abstract

A method of setting up a user equipment (UE) for an initial random access channel (RACH) procedure to a cellular network is provided. A configuration of a base station of a cellular network to receive an early indication of UE capabilities as part of a RACH procedure is communicated from the base station for at least one UE to receive prior to starting the RACH procedure.

Description

Technical Field

[0001] This disclosure relates to setting up a user equipment (UE) for an initial random access channel (RACH) procedure to a cellular network. Cellular network devices (e.g., a UE or base station at the cellular network) for such setup are also considered. Background Technology

[0002] The standard set by the 3rd Generation Partnership Project (3GPP) defines the procedures for a user (mobile) terminal or user equipment (UE) to access a cellular network through a radio access network (RAN) formed by cells (each cell having a corresponding base station). Reference Figure 1 The diagram illustrates a schematic message flow chart of a known contention-based random access (CBRA) process, which uses (a) a four-step random access and (b) a two-step random access. This drawing is based on an excerpt from Figure 9.2.6-1 of 3GPP Technical Specification (TS) 38.300 v.17.5.0. The process occurs between the base station (e.g., gNB for 5G RAN) 10 and the UE 20, and is generally understood within the context of 5G NR.

[0003] In the first step 21, UE 20 sends a random access preamble to the network. This is sometimes referred to as MSG1. In the four-step random access process, base station 10 responds with a random access response 11, which can be referred to as MSG2. UE 20 then sends a scheduling transmission 22, referred to as MSG3. In the two-step random access process, UE 20 also sends a Physical Uplink Shared Channel (PUSCH) payload 23 with the random access preamble 21, instead of the random access response 11 and scheduling transmission 22. In this case, MSG3 forms part of these UE transmissions, which can be referred to as step A. In both the two-step and four-step processes, base station 10 sends a contention resolution message 12 to the UE, which is referred to as MSG4 in the four-step random access process and as step B in the two-step random access process.

[0004] Once the RACH procedure, including security verification, is completed, the UE can notify the network of its capabilities. As described in 3GPP TS38.331, v.17.5.0, section 5.6.1.1, this capability can be retrieved by the network from the UE using the UE capability transport procedure. Now refer to... Figure 2 It describes (from TS 38.331, v.17.5.0) Figure 56.1.1-1 Schematic message flowchart of the existing process by which a UE transmits its UE capability information to the network. The network (base station) 10 transmits a UECapabilityEnquiry message 15 to the UE 20. The UE 20 then responds to the base station 10 with a UECapabilityInformation message 25, which indicates the UE's capabilities.

[0005] Recent developments in 3GPP standards have shown that, in some cases, it can be beneficial for the network to know the UE's capabilities before completing the RACH procedure. Specifically, for the UE, indicating capabilities as part of the MSG3 message can be advantageous. The configuration for the MSG4 message may differ depending on the capabilities sent in the MSG3 message. This presents a challenge because existing procedures for the UE to notify the network of its capabilities rely on the already completed RACH procedure, and the space available for messages conveyed as part of the RACH procedure can be limited. Summary of the Invention

[0006] Against this background, this disclosure provides a method for setting up a user equipment (UE) for an Initial Random Access Channel (RACH) procedure to a cellular network according to claim 1. A cellular network device configured to operate according to this method, conforming to claim 15, is also provided. Preferred and / or optional features are defined in the dependent claims.

[0007] The base station (e.g., gNB) sends and preferably broadcasts its configuration for an early indication of the UE's capabilities. This early indication is sent by the UE as part of the RACH procedure. Alternatively, the UE receives this configuration before starting the RACH procedure and can thus set it accordingly. Advantageously, this communication can be performed as part of a System Information Block (SIB) broadcast. For example, the communication can be part of SIB1, or alternatively, part of an on-demand SIB.

[0008] The communicated configuration can indicate which message (or which parts of messages) within the RACH procedure can be used to transmit early UE capability indications. For example, the MSG3 message might be appropriate. It should be noted that the base station can accept early UE capability indications in more than one way (and it may even be possible to combine these methods), and this can be indicated by the communicated configuration. Alternatively, the communicated configuration can indicate encodings or mappings understood by the network for use in transmitting early indications of UE capabilities by the UE. Again, the base station can understand more than one encoding or mapping, and this can be indicated in the communicated configuration.

[0009] As an example, a base station can instruct the UE to transmit UE capabilities in one or more specific portions of an MSG3 message. One option is for the UE to transmit UE capabilities in the Media Access Control (MAC) header of the MSG3 message, such as a reserved index within the Logical Channel ID (LCID) and / or a reserved (R) bit in the MAC header of the MSG3 message. Another option is for the UE to transmit UE capabilities in a Radio Resource Control (RRC) Connection Request message. Advantageously, one or more portions of such an indicated RRC Connection Request message may include some of the bits allocated in the RRC Connection Request message for the transmission of the UE's temporary identity. For example, a portion of the bits allocated in the RRC Connection Request message for the S-Temporary Mobile Subscriber Identity (S-TMSI) could be used. One possibility along these lines is to use a portion of the bits allocated within the S-TMSI for the Access and Mobility Management Function Identity (AMF-ID) in the RRC Connection Request message. In cases where a portion of the bits allocated to the S-TMSI in the RRC connection request message is used for early indication of UE capabilities, the communicated configuration may indicate: a mapping between those bits and a specific UE capability; and / or other bits of the S-TMSI (e.g., AMF-ID) communicated in the RRC connection establishment completion message. Another possibility includes the use of "alternate value" bits within the RRC message for the transmission of early indications of UE capabilities.

[0010] When the MSG3 message is used for early indication of UE capabilities, the early indication of UE capabilities is advantageously made while maintaining a 48- or 64-bit Common Control Channel (CCCH).

[0011] Therefore, based on the received configuration, the UE can be configured to convey an early indication of its capabilities as part of the RACH procedure (in other words, to set up the RACH procedure message, specifically the MSG3 message). When the UE sends the early indication as part of the RACH procedure (and conversely, the base station receives the configuration as part of the RACH procedure), the early indication is made according to the configuration conveyed by the base station. The RACH procedure may include two or four steps. Attached Figure Description

[0012] The method disclosed herein can be practiced in various ways; however, only one way will now be described by way of example and with reference to the accompanying drawings, in which: Figure 1 A schematic message flow diagram of a known contention-based random access (CBRA) is shown, which uses (a) a four-step random access; and (b) a two-step random access. Figure 2 Depicted (from TS 38.331, v.17.5.0) Figure 5 6.1.1-1 A schematic message flow diagram of the existing process by which a UE transmits its UE capability information to the network (copying). Figure 3 A schematic message flow diagram of a CBRA using four-step random access according to an embodiment of the present disclosure is shown; Figure 4 The known format of the Media Access Control (MAC) subheader (according to Figure 6.1.2-3 of 3GPP TS 38.321 v.17.5.0) is depicted; and Figure 5 The diagram illustrates (reproduced from Figure 8.1-1 of 3GPP TS 38.401, v.15.2.0) an existing schematic message flow diagram of the UE initial access procedure for the Radio Resource Control (RRC) protocol in a Central Unit / Distributed Unit (CU / DU) base station architecture.

[0013] In cases where one figure indicates a feature also shown in another figure, the same reference numerals have been used. Detailed Implementation

[0014] As discussed above, this disclosure extends existing methods for notifying the cellular network of UE capabilities after the initial UE access phase to this initial phase (specifically during the RACH procedure). In particular, recent developments within 3GPP have taken into account an increasing number of cases where it would be advantageous to notify the network of some UE capabilities earlier (especially during MSG3 delivery).

[0015] MSG3 includes Radio Resource Control (RRC) Connection Request messages. Furthermore, MSG3 is space-constrained and typically has two formats for the Common Control Channel (CCCH): a 48-bit CCCH format and a 64-bit CCCH1 format. It is expected that the upper length limit for these formats is fixed, as length impacts uplink coverage planning. Therefore, uplink CCCH messages are space-constrained, and no new information elements need to be introduced without expanding the Transport Block Size (TBS) and thus without affecting coverage. The same applies to the CCCH1 format. It should also be noted that CCCH messages can also carry RRC Recovery, RRC Reconstruction, and System Information (SI) Request messages. These are encoded differently, but it is expected that they all fit into either the 48-bit CCCH or 64-bit CCCH1 format. The CCCH1 format can only carry RRC Recovery 1 messages. As described in 3GPP TS 38.331, v.17.5.0, section 6.2.2, the “useFullResumeID” parameter is used to broadcast whether the cell supports the 48-bit CCCH or the 64-bit CCCH1 format. The length limitations on CCCH and CCCH1 messages make the additional transmission of early UE capability indications as part of the message more difficult.

[0016] According to this disclosure, there are many possible ways to achieve this. Each method may use different bits of the MSG3 message and / or different encodings of the UE's capabilities within those bits. The UE is unaware whether the network supports one or more methods. Therefore, it is expected that the UE knows the bits and / or encodings that the network (base station) will accept. Otherwise, it may use certain bits and / or encodings that the network will not understand, resulting in the entire MSG3 message potentially being rejected. In particular (and as discussed below), it may be possible to use reserved bits for early indication. Rejecting the MSG3 message may result in restarting the RACH procedure and re-establishing initial access.

[0017] Therefore, the base station provides this information to any UE that wants to access the network. Now refer to Figure 3 This illustrates a schematic message flow diagram of a CBRA using four-step random access according to an embodiment of the present disclosure. This is based on... Figure 1 (a), and the same features are indicated using the same reference numerals. As shown in this figure, base station 10 initially transmits 100 the configuration of an early indication of the base station's ability to receive UEs, which will be provided within or as part of the RACH procedure. Transmission 100 is performed before the start of the RACH procedure and is typically broadcast. In particular, it can be indicated within a System Information Block (SIB) such as SIB1.

[0018] The RACH procedure then proceeds as previously discussed. UE 20 sends a random access preamble 21 to the network, and base station 10 responds with a random access response 11. UE 20 then sends a modified MSG3 122 to base station 10, which includes an early indication of the UE's capabilities. This uses the configuration communicated to UE 20 in transmission 100. Finally, base station 10 sends a contention resolution message 12 to the UE. A four-step random access procedure is shown, but it will be understood that the corresponding method can be used for a two-step random access procedure.

[0019] Transmission 100 can indicate which method the network implements, and within that method, which bits are used for which purpose. The table below shows examples of how Transmission 100 can use coded 3 bits as part of system information transmission to signal some possible early UE capabilities. The specific techniques shown in this table are merely examples, but each technique will be discussed individually below. No "padding" bits are used in this example. .

[0020] Generally, a method for configuring a user equipment (UE) for an Initial Random Access Channel (RACH) procedure to a cellular network can therefore be considered. This method includes communicating from a base station of the cellular network an early indication of the base station's capability to receive a UE as part of the RACH procedure, for at least one UE to receive before the RACH procedure begins. In this context, the communication may include transmission by the base station (e.g., broadcast or directed transmission) and / or reception by the UE.

[0021] Specifically, the communicated configuration may indicate: one or more parts of at least one message within the RACH procedure that the UE can use for early indication of UE capabilities (i.e., which bits of which messages will be used by the UE for early indication of UE capabilities); and / or the encoding scheme for early indication of UE capabilities (i.e., how the information content of any bit used for early indication of UE capabilities is mapped to a specific UE capability). It will be understood that this indication may be based on, for example, a public protocol defined by a standard.

[0022] As an example, the configuration conveyed can be an early indication of UE capabilities, indicating one or more parts of the MSG3 message. The options for such parts of the MSG3 message will be discussed further below. The RACH procedure can include two or four steps. The MSG3 message can be defined for both options.

[0023] In an embodiment, this communication can be performed as part of a System Information Block (SIB) broadcast. Such a broadcast can be defined by a standard.

[0024] Advantageously, the steps communicated from the base station of the cellular network may include receiving the base station's configuration at the UE. Alternatively, the steps communicated from the base station of the cellular network may include configuring the UE, based on the communicated configuration, to communicate early indications of the UE's capabilities as part of the RACH procedure.

[0025] In an embodiment, the method may further include communicating an early indication of UE capabilities from the UE to the base station as part of a RACH procedure, based on a configuration communicated by the base station. Thus, the communicated configuration can be used by the UE to configure itself for transmitting UE capabilities, and these can then be transmitted accordingly.

[0026] Specific embodiments will now be discussed, particularly the specific manner in which early indications of UE capabilities (for which configuration can be communicated by the base station) are given. This disclosure will return to the general meaning discussed further below.

[0027] Several methods can utilize bits within the Media Access Control (MAC) header of the MSG3 message. One primary method is to use reserved bits within the Logical Channel ID (LCID) in the MAC header of the MSG3 message. The Logical Channel ID field identifies the logical channel instance corresponding to the MAC SDU or the type of MAC CE or padding. Each MAC subheader contains one LCID field. The LCID field is 6 bits in size. Table 6.2.1-2 of 3GPP TS 38.321 shows the possible code points or indices used for LCID values ​​in the Uplink Shared Channel (UL-SCH). For convenience, this table is copied below, where it can be seen that code points / indices 37-42 and 47 are indicated as "reserved" and can be used for early UE capability indication. .

[0028] The second possible method is to use reserved bits in the MAC Packet Data Unit (PDU) subheader. See below for further details. Figure 4 The document describes the known format of the Media Access Control (MAC) subheader (based on Figure 6.1.2-3 of 3GPP TS 38.321 v.17.5.0). The subheader format includes: a first reserved bit 301; a second reserved bit 302; and a 6-bit LCID 303. It is possible to use one of the reserved bits (e.g., the second reserved bit 302). Using this bit increases the possible encoded values ​​in the subheader from 64 (using the 6-bit LCID) to 128 (thus doubling the total number of values ​​or increasing the total number of values ​​by 64).

[0029] Other methods can use RRC connection request messages. See now for reference. Figure 5The figure illustrates an existing schematic message flow diagram of the UE initial access procedure for the Radio Resource Control (RRC) protocol in a Central Unit / Distributed Unit (CU / DU) base station architecture (copied from Figure 8.1-1 of 3GPP TS 38.401, v.15.2.0). Where the same features are shown in the previous figures, the same reference numerals have been used.

[0030] The entities shown in this figure are: UE 20; gNB-DU 111; gNB-CU 112; and Access and Mobility Management Function (AMF) 120. As explained in 3GPP TS 38.401, v.15.2.0, Section 8.1, the UE initial access procedure has the following steps.

[0031] UE 20 sends an RRC connection request message 201 to gNB-DU 111. In the context of the RACH procedure discussed above, the RRC connection request message 201 corresponds to (or forms part of) an MSG3 message. gNB-DU 111 includes the RRC message and the corresponding lower-layer configuration for the UE (if the UE is permitted) in an INITIAL UL RRC MESSAGE TRANSFER message 202 and transmits it to gNB-CU 112. The INITIAL UL RRC MESSAGE TRANSFER message 202 includes a C-RNTI assigned by gNB-DU 111. gNB-CU 112 assigns a gNB-CU UE F1AP ID to UE 20 and generates an RRC CONNECTION SETUP message toward UE 20. The RRC message is encapsulated in F1AP DL RRC Message Transmission (DL RRC MESSAGETRANSFER) message 203. gNB-DU 111 sends an RRC Connection Setup (RRC CONNECTION SETUP) message 204 to UE 20. This can correspond to (or form part of) the MSG4 message of the RACH procedure.

[0032] UE 20 sends an RRC Connection SETUP COMPLETE message 205 to gNB-DU 111. This is sometimes considered the MSG5 message of the RACH procedure. gNB-DU 111 encapsulates the RRC message in an F1AP UL RRC MESSAGE TRANSFER message 206 and sends it to gNB-CU 112. gNB-CU 112 sends an INITIAL UE MESSAGE message 207 to AMF 120. AMF 120 sends an INITIAL UE CONTEXT SETUP REQUEST message 208 to gNB-CU 112. gNB-CU 112 sends a UE CONTEXT SETUP REQUEST message 209 to establish the UE context in gNB-DU 111. This message can also encapsulate an RRC Security Mode Command message. gNB-DU111 sends an RRC Security Mode Command message 210 to UE 20.

[0033] gNB-DU 111 sends a UE context setup response (UE CONTEXT SETUP RESPONSE) message 211 to gNB-CU 112. UE 20 responds with an RRC security mode completion (RRC SECURITY MODE COMPLETE) message 212. gNB-DU 111 encapsulates the RRC message in an F1AP UL RRC message transfer (UL RRC MESSAGE TRANSFER) message 213 and sends it to gNB-CU 112. gNB-CU 112 generates an RRC connection reconfiguration (RRC CONNECTION RECONFIGURATION) message and encapsulates it in an F1AP DL RRC message transfer (DL RRC MESSAGE TRANSFER) message 214 destined for gNB-DU 111. gNB-DU 111 sends an RRC connection reconfiguration (RRC CONNECTION RECONFIGURATION) message 215 to UE 20.

[0034] UE 20 sends a RRC connection reconfiguration complete (RRC CONNECTION RECONFIGURATION COMPLETE) message 216 to gNB-DU 111. gNB-DU 111 encapsulates the RRC message in an F1AP UL RRC message transfer (UL RRC MESSAGE TRANSFER) message 217 and sends it to gNB-CU 112. gNB-CU 112 sends an initial UE context setup response (INITIAL UE CONTEXT SETUP RESPONSE) message 218 to AMF 120.

[0035] As pointed out above, the MSG3 message includes a CCCH, which includes a RRC connection request message that can be encoded in the following formats, some of which have been discussed above. The CCCH format is those parts indicated by an asterisk (*) below, which can be considered a total of 48 bits. .

[0036] As previously mentioned, an alternative option for the MSG3 message format is an RRC resume message, which can have the following format. The CCCH format is those parts indicated by an asterisk (*) below, which can be considered a total of 48 bits. .

[0037] As detailed in 3GPP TS 38.331, v.17.5.0, section 6.2, the RRCSetupRequest message for RRC connection establishment in NR has the following format.

[0038] Many possible techniques for conveying early UE capabilities can use RRC messages (e.g., as discussed above regarding Figure 5 discussed) and in particular the RRC connection request (RRC Connection Request) message 201 corresponding to the MSG3 message. Such a message can convey a UE temporary identity, such as an S-temporary mobile subscriber identity (S-TMSI) or an AMF-ID (which is part of the5G S-TMSI). These are typically conveyed in the RRC connection request message, although it will be understood that this is not required. Specifically, 3GPP TS 23.003, v.18.3.0, section 2.11 indicates that the 5G S-TMSI has the following structure: <5G-S-TMSI> = <AMF set ID><AMF pointer><5G-TMSI>.

[0039] In one such approach, some bits used to communicate the S-TMSI, and more specifically the AMF-ID, are instead used for early UE capabilities. The AMF-ID (AMF Set ID) uniquely identifies the AMF set within an AMF area and is typically 16 bits. In this case, the base station may additionally communicate (broadcast) a second table, for example, two octets, indicating which of the 16 bits are used to indicate which early capability is supported. The standard may specify how each of the most significant bits will correspond to a particular early capability. The bits from the AMF-ID used to indicate early UE capabilities can be configurable for each operator and / or sent from the core network to the base station (gNB). Furthermore, the bits from the S-TMSI (e.g., the AMF-ID) allocated for this purpose do not need to be consecutively positioned. As an illustrative example, bits 1, 5, 20, and 39 can be allocated from the AMF-ID bits to indicate early UE capabilities.

[0040] This approach works with CCCHs that include RRC connection request messages. However, because it does not include the UE ID, but instead includes a different encoding of the 24-bit RNTI that may not be available for early capability indication, it may not work with CCCHs that include RRC connection recovery messages.

[0041] In another such approach, fewer bits than the allocated 5G S-TMSI are used in MSG3, with the remaining bits used for early UE capability indication. Typically, 39 bits of S-TMSI are communicated in MSG3. These include the AMF-ID as discussed above. Instead of using all 39 bits for S-TMSI, the UE can use some (e.g., 31 bits) for S-TMSI communication and the remaining bits (8 bits in this example) for UE capability indication. In other words, the UE will still send 39 bits, but only 31 of those bits will be used for S-TMSI communication.

[0042] The remaining bits of the S-TMSI (e.g., 17 bits in the example of this document) are sent in MSG5 (RRC Connection Setup Complete message), which is not limited in size. In a two-step RACH procedure (where MSG1 and MSG3 messages are sent in step A), the remaining bits are sent in the next message after the contention resolution message (the contention resolution message is in step B). The network (base station) may broadcast these bits, which are normally allocated for S-TMSI communication in MSG3, to indicate which early capabilities (to be received by the UE).

[0043] In another such approach, the "alternate value" bit within the RRC message can be used for early UE capability indication. Some of these bits have already been discussed above. Again, the network can transmit (broadcast) encoding used to convey early UE capability indication using such bits.

[0044] Returning to the general meaning of this disclosure discussed above, further optional and / or preferred features will now be discussed. These features can also be understood as unique methods of conveying early indications of UE capabilities from the UE to the base station of the cellular network in one or more parts of a message forming part of the RACH procedure. Each of the general features discussed below can be considered in the context of two such methods.

[0045] In some embodiments, one or more portions may be one or more portions of the Media Access Control (MAC) header of the MSG3 message. In some embodiments, the one or more portions may be one or more portions of a Radio Resource Control (RRC) Connection Request message.

[0046] For example, one or more portions may include a reserved index within the Logical Channel ID (LCID) in the MAC header of the MSG3 message. Alternatively, the one or more portions may include reserved (R) bits in the MAC header of the MSG3 message.

[0047] In one embodiment, one or more portions may include a portion of the bits allocated in the RRC connection request message for the transmission of the UE temporary identity. For example, the one or more portions may include a portion of the bits allocated in the RRC connection request message for the S-Temporary Mobile Subscriber Identity (S-TMSI). The communicated configuration may then indicate a mapping between the bits of that portion and specific UE capabilities, and / or the communicated configuration may indicate that other bits of the S-TMSI are communicated in the RRC connection establishment complete message (MSG5 message). In another example, the one or more portions may include a portion of the bits allocated in the RRC connection request message for the Access and Mobility Management Function Identity (AMF-ID).

[0048] Optionally, the one or more portions may include the "alternate value" bit within the RRC message.

[0049] In an embodiment, the configuration indication conveyed is used for one or more portions of an MSG3 message that is an early indication of UE capabilities, such that the MSG3 message conveyed by the UE as part of the RACH procedure includes a 48- or 64-bit Common Control Channel (CCCH) that includes an early indication of UE capabilities.

[0050] Any method disclosed herein may be implemented at or as a cellular network device or entity or a station of a cellular network, configured to operate according to the method. In this context, examples of cellular network devices or entities may include a UE, a base station or cell, or an entity configured to operate or control a base station or cell. Other examples may include network nodes of a cellular network (e.g., an eNB or gNB). For example, a network entity may include a processor and at least one communication interface, particularly one or both of a transmitter and a receiver. A UE or user terminal may similarly include a processor and at least one communication interface, particularly one or both of a transmitter and a receiver. A controller for a cellular network device or entity may also be considered.

[0051] Any of the methods described herein can be implemented as a computer program. The computer program can be configured to control cellular network devices, nodes, or entities to perform any of the methods according to this disclosure.

[0052] While specific embodiments have now been described, those skilled in the art will understand that various modifications and variations are possible. For example, while this disclosure has been described with respect to existing network architectures, it will be understood that changes to the architecture (and / or nomenclature) and / or message types or formats are possible, but this disclosure may still remain applicable in such cases. Although SIB1 is indicated as a suitable transmission for conveying the base station's configuration for receiving early UE instructions, alternatives such as on-demand SIBs may be possible. Furthermore, combinations of any particular features shown with reference to one embodiment (or aspect) or multiple embodiments (or aspects) are provided, even if that combination has not been explicitly detailed herein.

Claims

1. A method for configuring a user equipment (UE) for an initial random access channel (RACH) procedure to a cellular network, the method comprising: The configuration of the base station of the cellular network to convey an early indication of the base station's ability to receive a UE as part of the RACH procedure, for at least one UE to receive before the RACH procedure begins.

2. The method according to claim 1, wherein, The configuration indications conveyed include: one or more portions of at least one message within the RACH procedure that the UE can use for early indication of UE capabilities; and / or the encoding scheme for early indication of UE capabilities.

3. The method according to claim 2, wherein, The configuration indications conveyed are one or more parts of the MSG3 message used for early indication of UE capabilities.

4. The method according to claim 3, wherein, The one or more portions are one or more portions of the Media Access Control (MAC) header of the MSG3 message, or one or more portions of the Radio Resource Control (RRC) Connection Request message.

5. The method according to claim 4, wherein, The one or more portions include a reserved index within the Logical Channel ID (LCID) in the MAC header of the MSG3 message and / or a reserved (R) bit in the MAC header of the MSG3 message.

6. The method according to claim 4 or claim 5, wherein, One or more portions include the bits allocated for the transmission of the UE's temporary identity in the RRC connection request message.

7. The method according to claim 6, wherein, The one or more portions include portions of the bits allocated for the S-Temporary Mobile Subscriber Identity (S-TMSI) in the RRC Connection Request message, preferably portions of the bits allocated for the Access and Mobility Management Function Identity (AMF-ID) in the RRC Connection Request message.

8. The method according to claim 7, wherein, The mapping between the portion of the communicated configuration indication bits and the specific UE capability, and / or the other bits of the S-TMSI communicated in the RRC connection establishment completion message.

9. The method according to any one of claims 3 to 8, wherein, One or more parts include the "alternate value" bit inside the RRC message.

10. The method according to any one of claims 3 to 9, wherein, The configuration indication conveyed is used for early indication of UE capabilities in one or more parts of the MSG3 message, such that the MSG3 message conveyed by the UE as part of the RACH procedure includes a 48- or 64-bit Common Control Channel (CCCH) that includes early indication of UE capabilities.

11. The method according to any of the preceding claims, wherein, The communication is performed as part of a System Information Block (SIB) broadcast.

12. The method according to any of the preceding claims, wherein, The steps of communicating from the base station of the cellular network include: receiving the configuration of the base station at the UE according to the communicated configuration, and / or configuring the UE to communicate early indications of UE capabilities as part of the RACH procedure.

13. The method according to any of the preceding claims, further comprising: Based on the configuration communicated by the base station, an early indication of the UE's capabilities is communicated from the UE to the base station as part of the RACH procedure.

14. The method according to claim 13, wherein, The RACH procedure consists of two or four steps.

15. A cellular network device configured to operate according to the method of any of the preceding claims.

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