Patent Description:
The present disclosure generally relates to the field of communications, and more particularly, to wireless communications methods, devices, and networks.

"Consideration on extending the code space for <NUM>-S-TMSI" relates to mechanisms to transmit the <NUM>-bit <NUM>-S-TMSI under the size limitation of MSG3.

In the new third generation partnership project (3GPP) standard 5GS, the system and architecture for <NUM> and various state machines are described.

One "state machine" is the connection management state model or CM-state model, described in 3GPP technical specification (TS) <NUM>.

Generally, connection management comprises functions for establishing and releasing signaling connections between a user equipment (UE) and core network node, for <NUM> this node is called AMF (Access and Mobility Management Function).

<FIG> illustrates an example of a <NUM> system architecture, including Nodes (e.g., AMF, UE, (R)AN) and interface names. Connection management is about signaling connection over the N1 interface as illustrated in <FIG>.

This signaling connection over N1 is used to enable Non-Access-Stratum (NAS) signaling exchange between the UE and the core network. It comprises both the AN signaling connection between the UE and the AN (Access Node) and the N2 connection, between the AN and the AMF.

Referring also to <FIG> is a diagram illustrating CM state transition in the UE and <FIG> is a diagram illustrating CM state transition in the AMF. There are two CM-states defined, CM-IDLE and CM-CONNECTED.

A UE in CM-IDLE has no NAS signaling connection established over N1 to the AMF and in this CM-state, the UE performs cell selection/reselection and public land mobile network (PLMN) selection. In addition, there is no AN signaling connection or N2/N3 connections for a UE in idle state.

If the UE is registered to the network and in CM-IDLE, it shall usually listen to and respond to paging messages from the network. This means that in CM-IDLE the UE is still reachable. If initiated by the user/UE, the UE shall also be able to perform a service request procedure.

A UE in CM-CONNECTED is a UE that has established an access node (AN) signaling connection between the UE and the AN, the UE has entered an RRC_CONNECTED state over 3GPP access. Over this connection, the UE can transmit an initial NAS message (for example a service request) and this message initiates the transition from CM-IDLE to CM CONNECTED in the AMF. As shown in <FIG>, CM-CONNECTED may require an N2 connection between the access node (AN) and the AMF. The reception of an initial N2 message (e.g., N2 Initial UE message) initiates the transition for AMF from CM-IDLE to CM-CONNECTED state.

In the CM-CONNECTED state, the UE can transmit data, and the UE shall be ready to enter CM-IDLE, whenever AN signalling connection is released. The AMF enters CM-IDLE whenever the logical N1 signalling connection and the N3 user plane connection are released.

In a similar way as in the AMF, there is also a state model in the AN, the access network.

Certain embodiments in this disclosure use a "gNB" to refer to the access network node. The term "gNB" shall be considered an example of a type of access network node, rather than a limitation in the applicability of the present disclosure. In other embodiments, other types of access network nodes could be used, such as an ng-eNB or an eNB.

One state model in the gNB is the RRC State machine. <FIG> is an illustration of operation of an RRC state machine. A UE can either be in RRC_CONNECTED, RRC_INACTIVE or RRC_IDLE. <FIG> is an illustration of how the RRC State machine is intended to work and the messages used to trigger/transition a UE between the states. The indications in parenthesis (SRB0, SRB1) indicate what signalling radio bearer can be used to transition the UE between the states. <FIG> also shows the principles for transition, not necessarily all the messages will have the same names in the final standard. The mapping between the different state machines, the one in the AN and the one in AMF, is such that CM-CONNECTED can map to either RRC_CONNECTED or RRC_INACTIVE - while CM-IDLE always map to RRC_IDLE.

A UE is either in RRC_CONNECTED state or in RRC_INACTIVE state when an RRC connection has been established. If this is not the case, i.e., no RRC connection is established, the UE is in RRC_IDLE state. These different states are further described in 3GPP TS <NUM>.

In RRC_IDLE, the UE is configured to listen to a paging channel at certain occasions and it performs cell (re)selection procedures and listens to system information.

In RRC_INACTIVE, the UE is also listening to the paging channel and does cell (re)selection procedures, but in addition, the UE also maintains a configuration and the configuration is also kept on the network side, such that, when needed, e.g., when data arrives to the UE, the UE doesn't require a complete setup procedure to start transmitting data.

In RRC_CONNECTED, there is transfer of data to or from the UE and the network controls the mobility. This means that the network controls when the UE should handover to other cells. In the connected state, the UE still monitors the paging channel and the UE monitors control channels that are associated with whether there is data for the UE or not. The UE provides channel quality and feedback information to the network and the UE performs neighboring cell measurement and reports these measurements to the network.

When a UE is in CM-CONNECTED and RRC_INACTIVE the following applies:.

The AMF, based on network configuration, may provide assistance information to the next generation radio access network (NG-RAN), to assist the NG-RAN's decision whether the UE can be sent to RRC Inactive state.

The "RRC Inactive assistance information" can for example include:.

The RRC Inactive assistance information mentioned above is provided by the AMF during N2 activation with the (new) serving NG-RAN node (i.e., during Registration, Service Request, or handover) to assist the NG RAN's decision whether the UE can be sent to RRC Inactive state. RRC Inactive state is part of the RRC state machine, and it is up to the RAN to determine the conditions to enter RRC Inactive state. If any of the parameters included in the RRC Inactive Assistance Information changes as the result of NAS procedure, the AMF shall update the RRC Inactive Assistance Information to the NG-RAN node.

The state of the N2 and N3 reference points are not changed by the UE entering CM-CONNECTED with RRC Inactive state. A UE in RRC inactive state is aware of the RAN Notification area (RNA).

A UE in the RRC_INACTIVE state can be configured with an RNA (RAN-based Notification Area), where:.

There are several different alternatives on how the RNA can be configured:.

At transition into CM-CONNECTED with RRC Inactive state, the NG-RAN configures the UE with a periodic RAN Notification Area Update timer taking into account the value of the Periodic Registration Update timer value indicated in the RRC Inactive Assistance Information and uses a guard timer with a value longer than the RAN Notification Area Update timer value provided to the UE.

If the periodic RAN Notification Area Update guard timer expires in RAN, the RAN can initiate AN Release procedure as specified in TS <NUM> [<NUM>].

When the UE is in CM-CONNECTED with RRC inactive state, the UE performs PLMN selection procedures as defined in TS <NUM> [<NUM>] for CM-IDLE.

When the UE is CM-CONNECTED with RRC Inactive state, the UE may resume the RRC connection due to:.

When Resuming, UE will include an identifier to the network that will inform the network node about where the UE context describing the specifics of the UE, e.g., bearers, tracking area, slices, security credentials/keys etc.) such that resuming will bring the UE to an RRC_CONNECTED configuration similar to when it was resumed. The Identifier pointing to the UE Context is called I-RNTI, Inactive Radio Network Temporary Identifier. In connection to when the UE is suspended, i.e., the UE is transitioned from RRC_CONNECTED to RRC_INACTIVE, the UE is provided with an I-RNTI from the network. The network allocates an I-RNTI when transitioning UE to RRC_INACTIVE and the I-RNTI is used to identify the UE context, i.e., as an identifier of the details stored about the UE in the network while in RRC_INACTIVE.

Now, while the above has mainly been a description about NR, the new radio connected to a <NUM> core network, or <NUM> system, it is equally applicable to situations when LTE connects to a <NUM> system. There is thus also a possibility to run LTE radio in the radio network but connecting to a system that is not an evolved packet core (EPC) system, but that includes the architecture according to above, e.g., with N2 interfaces towards AMF's.

In such situations, there will also be an RRC_INACTIVE defined, with the same specifics as is described above for NR.

Looking now more in detail on the RRC Request or RRC Connection Request procedure. In LTE it is called RRC Connection Request. In NR it is called RRC Request. These terms may be used interchangeably and specify what access is being requested. If not specified, it will be as defined above. As is indicated by the RRC state diagram in <FIG>, this procedure occurs when the UE is in RRC_IDLE.

In RRC_IDLE before the UE has registered with a core network, the UE needs to send an RRC request to request a signaling connection as illustrated in <FIG>. Typically, the request to the network can be either accepted or the request can be rejected, as illustrated in <FIG>:
<FIG> illustrates a successful procedure. The first message in <FIG>, the RRCRequest message is commonly also referred to as msg3 (short for message <NUM>) as it is the <NUM>rd message in order (there are <NUM> messages not carrying any RRC, for requesting resources (msg1) to send msg3 and for receiving grants (msg2) for such resources). To continue, RRC setup is commonly referred to as msg4 and RRC Setup complete as msg5. It should be noted though that msg3 - <NUM> are also used as denoting interactions between UE and Network also in other procedures, e.g., resume procedures. Thus, msg3 and msg4-msg5 are more generic terms that simply refer to messages in a particular order.

The purpose of this example procedure is to establish an RRC connection. RRC connection establishment involves SRB1 (Signaling Radio Bearer <NUM>) establishment. The procedure is also used to transfer the initial NAS dedicated information/ message from the UE to the network.

The network applies the procedure as follows:.

The UE initiates the procedure when upper layers request establishment of an RRC connection while the UE is in RRC_IDLE.

Upon initiation of the procedure, the UE shall, among other things, start a timer and initiate transmission of the RRCRequest message.

The UE shall set the content of the RRC message as follows:.

The UE shall submit the RRCRequest message to lower layers for transmission.

There are of course other aspects than identifiers to consider also, but for purposes of this disclosure, some steps are omitted.

If successfully received and accepted by the network node, the UE will receive an RRC Setup message, (msg4). In response to the setup message, it shall send msg5, the complete message. In this message UE may include NAS messages to the network.

The format and content of the RRC Request message is similar in both LTE and NR.

Now, the message size of the RRCRequest message is limited both in NR and in LTE. In particular, in LTE, it is not possible to fit in more information than what is already specified and thus, any change to format may not be possible. Accordingly, any addition proposals that change the amount of information in the RRCRequest to require more bits presents difficulties. This may pose a particular problem when LTE is connected to 5GC, as this combination may be constrained by both the LTE air interface, and the need to add new information for NR. The RRC Request message in NR is new and does not suffer from the constraints that LTE does.

One particular aspect that is being raised is an extension of the <NUM>-S-TMSI code length that is being allocated by the network upper layers (Non-access Stratum) to the UE once registered.

In LTE earlier releases, when LTE only connected to EPC, the ID was instead an S-TMSI that was <NUM> bits in length and this was included in RRC Connection Request messages after a UE was registered.

Now, with LTE having this <NUM> bit constraint, any longer Identifier fields will be difficult to include in the request message.

It is also possible that NR may have limitations in their space of identifiers in the corresponding msg3. It is not yet concluded that it will be possible to include longer identifiers in NR either, in which case, the challenge with a longer <NUM>-S-TMSI is also applicable for NR.

It thus becomes a problem if the <NUM>-S-TMSI, which will need to be included in the RRC Connection Request procedure in LTE when connected to 5GC, will be extended to, e.g., <NUM> bits for example.

There currently exist certain challenge(s). As described above, there is a problem with using extended lengths on identifier <NUM>-S-TMSI, in particular, when it is going to be mapped to the bit-constrained msg3 / RRC connection request message in LTE. In LTE, the identifier included is <NUM> bits and anything longer than this will not fit into the message <NUM> that includes the RRCConnection Request.

Certain aspects of the present disclosure and their embodiments may provide solutions to these or other challenges. Certain embodiments provide solutions for signalling of an extended <NUM>-S-TMSI that is longer than <NUM> bits.

Aspects of the invention are set out in the independent claims appended hereto.

There are, proposed herein, various embodiments which address one or more of the issues disclosed herein. As one example, in certain embodiments, only part of the <NUM>-S-TMSI is included in msg3 (instead of including the <NUM>-S-TMSI identifier in full in msg3). The rest of the <NUM>-S-TMSI identifier, for which there may be no room in msg3, is instead included in a second message or in msg5.

The identifier allocated by upper layers, although important for upper layers, is not used in any communication towards upper layers until after reception of message <NUM>. Translating this to an RRC Request procedure where the <NUM>-S-TMSI is used, the actual identifier is not needed towards upper layers until after reception of RRCRequest Complete message and thus, what parts are not fitting in msg3 are included in message <NUM>.

According to another embodiment of the present disclosure, the complete <NUM>-S-TMSI is included in message <NUM> instead of in message <NUM>. In such situations, it is necessary to include another identifier in message <NUM> for purposes of returning an identifier in message <NUM> to make sure handshake is done with the correct UE. This other identifier is, prior to registration and reception of a <NUM>-S-TMSI, specified to be a random value. One aspect of the present disclosure is thus to use the random value approach not only when the UE is not registered and has not received a <NUM>-S-TMSI, but also in situations when it actually has received a <NUM>-S-TMSI.

According to the embodiments of the present disclosure, even a bit-constrained message <NUM> like the RRC Connection Request message in LTE, can manage a large upper layer identifier.

According to another aspect of the present disclosure, the split of <NUM>-S-TMSI is done in a way such that a specific part of the <NUM>-S-TMSI is signaled in msg3 and another specific part in msg5, or a message that is sent after msg3.

The specific part that is signaled after message <NUM> is corresponding to parts of an AMF identity.

In connection to this aspect of the present disclosure, the part of the <NUM>-S-TMSI that is signaled in message <NUM> is combined with a random number sequence.

In connection to another aspect of the present disclosure, the part of the <NUM>-S-TMSI that is signaled in msg3 is a combination of AMF pointers and a portion of <NUM>-TMSI.

Certain embodiments may provide one or more of the following technical advantage(s). Advantages of the disclosure is that both NR and LTE connected to 5GS and a <NUM> core network can manage a longer <NUM>-S-TMSI, for example <NUM> bits.

Additional information may also be found in the document(s) provided in the Appendix.

<FIG> illustrates two different cells <NUM>, <NUM>, served by nodes <NUM> and <NUM> respectively. They are both connected to a <NUM> System <NUM>. Node <NUM> is an ng-eNB offering access through LTE air interface and Node <NUM> is a gNB offering access through NR air interface. The radio spectrum used in cell <NUM> and <NUM> can be the same or different. Further, the spectrum bands may be the same or different. For example, cell <NUM> may utilize bands in the <NUM> spectrum regime whereas cell <NUM> may offer access through spectrum in other bands, like the <NUM>, <NUM>, <NUM>, <NUM> or <NUM> band.

A wireless device (UE <NUM>) is shown in <FIG> as moving from cell <NUM> to cell <NUM>. Dependent on what state the UE is in, different things will happen when the UE enters cell <NUM>. The present disclosure discusses states when the UE is allocated a <NUM>-S-TMSI.

When a UE has performed an initial RRCConnectionRequest successfully and managed to register with the <NUM> System, whether it is through accessing via a gNB (NR) or accessing via an ng-eNB (LTE) it will be allocated a <NUM>-S-TMSI.

The intention is that this <NUM>-S-TMSI will be used to identify a UE when communicating with the network.

In one embodiment of the present invention, accessing through an ng-eNB only allows a <NUM> bit identifier. If the <NUM>-S-TMSI allocated to the UE is larger than <NUM> bits, the UE will do the following:
In relation to preparing the RRC Connection Request message to be sent from the UE to the ng-eNB, the UE will include parts of the <NUM>-S-TMSI. In one example, it will include <NUM> bits, the same as the limit of the identifier. The exact bits to include may be either agreed between the UE and the network node, or it may be standardized that if splitting a <NUM>-S-TMSI a certain method should be used, e.g., the most significant bits or the least significant bits may be selected to be included in msg3.

Further, the UE will include the remaining bits in subsequent message <NUM> that is transmitted from the UE to the network after reception of a setup message in message <NUM>.

<FIG> illustrates the procedure on the UE side. In step <NUM> there is a check in the UE prior to sending an RRCConnectionRequest message, e.g., in LTE connected to 5GC. If the identifier associated with the wireless device (in our case the <NUM>-S-TMSI) is larger than the limit in step <NUM>, then there should be a split (<NUM>) otherwise the identifier should be used in full (<NUM>). In the next step <NUM>, UE transmits two parts, one part (part <NUM>) in msg3 and one part (part <NUM>) in msg5.

In case the identifier associated with the wireless device is a split identifier there may also be inserted an indication about this in msg5 (if there are options).

Alternatively, it may be that the request message includes an indication that the identifier is a split identifier.

On the network node, the <NUM>-S-TMSI will be re-assembled and used/ included in communication towards the network <NUM> to identify communication from the particular UE.

According to another aspect of the present invention, and as illustrated in <FIG>, the UE may instead select to include the complete identifier received from upper layers, by the network in message <NUM> when performing the procedure of RRC Connection Request- Setup and Complete.

According to another aspect of the present disclosure, it is not necessarily the case that there is a need to wait until msg5 when there is a shortage of space in msg3. It may be equally possible to include an additional message, called msg3. <NUM>, to use only for when there is not enough room in msg3 to fit the necessary bits. This is illustrated as an alternative embodiment of the present disclosure.

<FIG> illustrates the embodiment according to the present disclosure, where the second part of the identifier associated with the wireless device or UE is sent in a message subsequent to msg3.

According to another aspect of the present disclosure, the split into part <NUM> and part <NUM> of the identifier associated with the wireless device or UE (<NUM>-S-TMSI) follow a specific procedure.

The <NUM>-S-TMSI is built up from a set of other identifiers, according to:
<<NUM>-S-TMSI> := <AMF Set ID> <AMF Pointer> <<NUM>-TMSI>.

The lengths of the different identifiers are:.

The important aspect of including an identifier at all in msg3 in the setup request, when there is no AS context that needs to be retrieved, is mainly to avoid collision, i.e., it is for purposes of contention resolution. As described above, it can either be a random value or a part of the <NUM>-S-TMSI.

Since splitting the <NUM>-S-TMSI is considered, from a contention resolution perspective, according to another embodiment of the present disclosure, we propose to maintain a <NUM>-bit field in msg3. This would then mean that we don't have to change anything with respect to the MAC CE for contention resolution, since this is already calculated based on a <NUM>-bit identifier.

The next question to address is what <NUM> bits should be included in part <NUM> in msg3, and what bits should be left to msg5, or a message that comes after msg3, e.g., msg3.

<FIG> is a table illustrating a comparison of Global Unique Temporary Identifier (GUTI) lengths for Access Mobility Management Function (AMF) and Mobile Management Entity (MME). In <FIG>, the <NUM>-TMSI and the M-TMSI are of equal length and allocated by AMF/MME. In addition to the <NUM>-TMSI and the M-TMSI, there is the MME Code and the AMF pointer and possibly part of AMF set ID.

The MME Code is most likely not contributing a lot to the contention resolution success as it is probably the same for very many UE's. From a contention success perspective, the <NUM>-TMSI and M-TMSI are important for msg3.

According to one aspect of the present disclosure, the <NUM>-TMSI is part of the first message or msg3. However, the <NUM>-TMSI is only <NUM> bits and it is possible and desirable to, from a contention resolution perspective, include <NUM> bits. Accordingly, an <NUM>-bit random value is included as part of msg3 to achieve the <NUM> bits and to also optimize the contention resolution success.

According to one aspect, part <NUM> of the first message or msg3 consists of <NUM>-TMSI (<NUM> bits) + Random number (<NUM> bits)
In another aspect of the present disclosure, and in situations when it may be considered more important to get an early indication of AMF identity, e.g., for routing purposes or for purposes of being able to do, e.g., load control of AMF's, it would be possible to select another set of bits. According to another aspect of the present disclosure, it would be possible to include, as part <NUM> of the transmission in msg3 the following:.

In part <NUM>, sent in a second message for example, msg3. <NUM> or msg5 or at least in a message subsequent to msg. <NUM>, it would be possible to include the last <NUM> bits of the <NUM>-TMSI. Typically, the bits can be the least significant bits or the most significant bits, or any pre-determined bits of the <NUM>-TMSI <NUM>-bit value.

The advantage of this embodiment of the present disclosure is that it would allow an early identification of the AMF, already directly after msg3 and it would be possible to, e.g., do early overload control and possibly reject the UE already at the reception of msg3, if it is determined that the AMF is overloaded. The trade-off made is that it is likely that the AMF part of part <NUM>, the AMF set ID and the AMF pointer are likely to be the same for many UE's and as such are not optimal as being part of the contention resolution identity. It should however be considered in comparison to the advantage received with getting early identifiers of AMF.

The methods described herein are applicable for both transmitting msg3 with LTE radio access as well as with NR radio access, when connecting to a <NUM> core network. Splitting the identifier is considered important when there is a shortage of identifier space rather than be restricted by particular accesses.

Although the subject matter described herein may be implemented in any appropriate type of system using any suitable components, the embodiments disclosed herein are described in relation to a wireless network, such as the example wireless network illustrated in <FIG>. For simplicity, the wireless network of <FIG> only depicts network <NUM>, network nodes <NUM> and 1060b, and WDs <NUM>, 1010b, and 1010c. In practice, a wireless network may further include any additional elements suitable to support communication between wireless devices or between a wireless device and another communication device, such as a landline telephone, a service provider, or any other network node or end device. Of the illustrated components, network node <NUM> and wireless device (WD) <NUM> are depicted with additional detail. The wireless network may provide communication and other types of services to one or more wireless devices to facilitate the wireless devices' access to and/or use of the services provided by, or via, the wireless network.

As used herein, wireless device (WD) refers to a device capable, configured, arranged and/or operable to communicate wirelessly with network nodes and/or other wireless devices. Unless otherwise noted, the term WD may be used interchangeably herein with user equipment (UE). Communicating wirelessly may involve transmitting and/or receiving wireless signals using electromagnetic waves, radio waves, infrared waves, and/or other types of signals suitable for conveying information through air. In some embodiments, a WD may be configured to transmit and/or receive information without direct human interaction. For instance, a WD may be designed to transmit information to a network on a predetermined schedule, when triggered by an internal or external event, or in response to requests from the network. Examples of a WD include, but are not limited to, a smart phone, a mobile phone, a cell phone, a voice over IP (VoIP) phone, a wireless local loop phone, a desktop computer, a personal digital assistant (PDA), a wireless cameras, a gaming console or device, a music storage device, a playback appliance, a wearable terminal device, a wireless endpoint, a mobile station, a tablet, a laptop, a laptop-embedded equipment (LEE), a laptop-mounted equipment (LME), a smart device, a wireless customer-premise equipment (CPE). a vehicle-mounted wireless terminal device, etc. A WD may support device-to-device (D2D) communication, for example by implementing a 3GPP standard for sidelink communication, vehicle-to-vehicle (V2V), vehicle-to-infrastructure (V2I), vehicle-to-everything (V2X) and may in this case be referred to as a D2D communication device. As yet another specific example, in an Internet of Things (IoT) scenario, a WD may represent a machine or other device that performs monitoring and/or measurements, and transmits the results of such monitoring and/or measurements to another WD and/or a network node. The WD may in this case be a machine-to-machine (M2M) device, which may in a 3GPP context be referred to as an MTC device. As one particular example, the WD may be a UE implementing the 3GPP narrow band internet of things (NB-IoT) standard. Particular examples of such machines or devices are sensors, metering devices such as power meters, industrial machinery, or home or personal appliances (e.g. refrigerators, televisions, etc.) personal wearables (e.g., watches, fitness trackers, etc.). In other scenarios, a WD may represent a vehicle or other equipment that is capable of monitoring and/or reporting on its operational status or other functions associated with its operation. A WD as described above may represent the endpoint of a wireless connection, in which case the device may be referred to as a wireless terminal. Furthermore, a WD as described above may be mobile, in which case it may also be referred to as a mobile device or a mobile terminal.

Using one or more input and output interfaces, devices, and circuits, of user interface equipment <NUM>, WD <NUM> may communicate with end users and/or the wireless network and allow them to benefit from the functionality described herein.

Network connection interface <NUM> may be configured to provide a communication interface to network 1143a. Network 1143a may encompass wired and/or wireless networks such as a local-area network (LAN), a wide-area network (WAN), a computer network, a wireless network, a telecommunications network, another like network or any combination thereof. For example, network 1143a may comprise a Wi-Fi network.

In <FIG>, processing circuitry <NUM> may be configured to communicate with network 1143b using communication subsystem <NUM>. Network 1143a and network 1143b may be the same network or networks or different network or networks. Communication subsystem <NUM> may be configured to include one or more transceivers used to communicate with network 1143b.

Network 1143b may encompass wired and/or wireless networks such as a local-area network (LAN), a wide-area network (WAN), a computer network, a wireless network, a telecommunications network, another like network or any combination thereof. For example, network 1143b may be a cellular network, a Wi-Fi network, and/or a near-field network.

In some embodiments, some signalling can be affected with the use of control system <NUM> which may alternatively be used for communication between the hardware nodes <NUM> and radio units <NUM>.

Access network <NUM> comprises a plurality of base stations 1312a, 1312b, 1312c, such as NBs, eNBs, gNBs or other types of wireless access points, each defining a corresponding coverage area 1313a, 1313b, 1313c. Each base station 1312a, 1312b, 1312c is connectable to core network <NUM> over a wired or wireless connection <NUM>. A first UE <NUM> located in coverage area 1313c is configured to wirelessly connect to, or be paged by, the corresponding base station 1312c. A second UE <NUM> in coverage area 1313a is wirelessly connectable to the corresponding base station 1312a.

It is noted that host computer <NUM>, base station <NUM> and UE <NUM> illustrated in <FIG> may be similar or identical to host computer <NUM>, one of base stations 1312a, 1312b, 1312c and one of UEs <NUM>, <NUM> of <FIG>, respectively.

Wireless connection <NUM> between UE <NUM> and base station <NUM> is in accordance with the teachings of the embodiments described throughout this disclosure. One or more of the various embodiments improve the performance of OTT services provided to UE <NUM> using OTT connection <NUM>, in which wireless connection <NUM> forms the last segment. More precisely, the teachings of these embodiments may improve UE compatibility with different types of networks and thereby provide benefits such as reduced user waiting times or better responsiveness. For example, a UE may be able to connect to a network node that would otherwise have difficulty handling the length of a <NUM>-S-TMSI assigned to the UE.

<FIG> depicts a method in accordance with particular embodiments, comprises determining to send at least a portion of an identifier associated with a wireless device in a msg5, wherein the length of the identifier exceeds a limit that a network node is capable of receiving in msg3 (step <NUM>); transmitting a msg3 to a network node, the msg3 comprising a portion of the identifier associated with the wireless device or a random value provided in lieu of the identifier associated with the wireless device (step <NUM>); and transmitting a msg5 to the network node, the msg5 comprising the at least a portion of the identifier associated with the wireless device or the entire identifier associated with the wireless device (step <NUM>).

<FIG> illustrates a schematic block diagram of an apparatus <NUM> in a wireless network (for example, the wireless network shown in <FIG>). The apparatus may be implemented in a wireless device or network node (e.g., wireless device <NUM> or network node <NUM> shown in <FIG>). Apparatus <NUM> is operable to carry out the example method described with reference to <FIG> and possibly any other processes or methods disclosed herein. It is also to be understood that the method of <FIG> is not necessarily carried out solely by apparatus <NUM>. At least some operations of the method can be performed by one or more other entities.

Virtual Apparatus <NUM> may comprise processing circuitry, which may include one or more microprocessor or microcontrollers, as well as other digital hardware, which may include digital signal processors (DSPs), special-purpose digital logic, and the like. The processing circuitry may be configured to execute program code stored in memory, which may include one or several types of memory such as read-only memory (ROM), random-access memory, cache memory, flash memory devices, optical storage devices, etc. Program code stored in memory includes program instructions for executing one or more telecommunications and/or data communications protocols as well as instructions for carrying out one or more of the techniques described herein, in several embodiments. In some implementations, the processing circuitry may be used to cause Message Configuring unit <NUM>, Message Transmitting unit <NUM>, and any other suitable units of apparatus <NUM> to perform corresponding functions according one or more embodiments of the present disclosure.

As illustrated in <FIG>, apparatus <NUM> includes Message Configuring Unit <NUM> and Message Transmitting unit <NUM>. Message Configuring unit <NUM> is configured to configure msg3 and msg5. For example, if an identifier associated with a wireless device (e.g., <NUM>-S-TMSI) exceeds a limit (e.g., more than <NUM> bits), Message Configuration unit <NUM> configures msg5 to include at least a portion of the identifier. In one embodiment, Message Configuration unit <NUM> splits the identifier between msg3 and msg5. How to split the identifier (e.g., how many bits of the identifier to configure in msg3, how many bits of the identifier to configure in msg5, and which of msg3 or msg5 is to include the most significant bits) may be pre-defined (e.g., based on rules stored in memory) or determined based on signalling exchanged with a network node. Message Transmitting unit <NUM> receives msg3 and msg5 from Message Configuration unit <NUM> and transmits msg3 and msg5 to a network node, for example, according to a procedure to establish or resume an RRC connection.

In some embodiments a computer program, computer program product or computer readable storage medium comprises instructions which when executed on a computer perform any of the embodiments disclosed herein. In further examples the instructions are carried on a signal or carrier and which are executable on a computer wherein when executed perform any of the embodiments disclosed herein.

In Ran2#101bis (Sanya) it was discussed how an increased length of <NUM>-S-TMSI would be handled given the limited size of msg3. As it is not really critical to get the identifier provided by CN (Like <NUM>-S-TMSI) until after msg5, it was, after an off-line discussion [<NUM>] possible to reach the following agreement:.

Prior to this, SA2 had verified that the length of the <NUM>-S-TMSI is going to be <NUM> bits [<NUM>].

This contribution addresses the split of <NUM>-S-TMSI.

This is however not the basis for the <NUM>-bit <NUM>-S-TMSI, instead, the proposal that triggered LS is described in [<NUM>] and include:.

The important aspect of including an identifier in msg3 in setup request, when there is no AS context that needs to be retrieved, is mainly to avoid collision, i.e., it is for purposes of contention resolution. In [<NUM>], we described that the identifier in msg3 can either be a random value or a part of the <NUM>-S-TMSI.

Since splitting the <NUM>-S-TMSI is considered, from a contention resolution perspective, we propose to maintain a <NUM>-bit field in msg3. This would then mean that we don't have to change anything with respect to the MAC CE for contention resolution, since this is already calculated based on a <NUM>-bit identifier.

The next question to address is what <NUM> bits that should be included in msg3, and what bits that should be left to msg5.

Below is a comparison figure taken from [<NUM>], illustrating the GUTI both with MME and AMF. In the figure below, the <NUM>-TMSI and the M-TMSI are of equal length and allocated by AMF/MME. In addition to these, there's the MME Code and the AMF pointer and possibly part of AMF set ID.

The MME Code is most likely not contributing a lot to the contention resolution success as it is probably the same for very many UE's. From a contention success perspective, it is <NUM>-TMSI and M-TMSI that are important for msg3.

As the NG-RAN node (ng-eNB, gNB) does not have to route any information to the core network until after msg5, there is no particular need to include AMF information until in msg5. The NG-RAN node will not have any use of it anyway. However, for the sake of keeping it to <NUM> bits, we propose to follow one of the following proposals:.

Option b) above has the advantage that it will improve the contention resolution, whereas option a) has the advantage that there will be <NUM> less bits to transfer in msg5.

For the sake of not splitting already existing fields, and define new (partial) fields, we propose to follow b) above and add a random <NUM>-bit sequence in addition to <NUM>-TMSI in msg3.

Some normal text (Body Text). Assign this style by pressing Alt-B.

In section <NUM> we made the following observations:.

Based on the discussion in section <NUM> we propose the following:.

Claim 1:
A method of operation of a wireless device (<NUM>) in a wireless network (<NUM>), the method comprising:
transmitting (<NUM>) a first message to a network node (<NUM>), the first message comprising at least a first portion of an identifier associated with the wireless device and at least a first portion of an access and mobility management (AMF) identifier (ID), wherein the first message does not comprise a complete identifier associated with the wireless device; and
transmitting (<NUM>) a second message to the network node, the second message comprising a second portion of the identifier associated with the wireless device, and wherein the second message comprises the first portion and a second portion of the AMF ID.