[0001] Some example embodiments may generally relate to mobile or wireless telecommunication systems, such as Long Term Evolution (LTE) or fifth generation (5G) radio access technology or new radio (NR) access technology, or other communications systems. For example, certain embodiments may relate to systems and/or methods for registering a global system for mobile communication (GSM) user, and in particular a GSM-railway (GSM-R) user.

BACKGROUND:

[0002] Examples of mobile or wireless telecommunication systems may include the Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access Network (UTRAN), Long Term Evolution (LTE) Evolved UTRAN (E-UTRAN), LTE- Advanced (LTE-A), MulteFire, LTE-A Pro, and/or fifth generation (5G) radio access technology or new radio (NR) access technology. 5G wireless systems refer to the next generation (NG) of radio systems and network architecture. 5G is mostly built on a new radio (NR), but a 5G (or NG) network can also build on E-UTRA radio. It is estimated that NR may provide bitrates on the order of 10-20 Gbit/s or higher, and may support at least enhanced mobile broadband (eMBB) and ultra-reliable low-latency- communication (URLLC) as well as massive machine type communication (mMTC). NR is expected to deliver extreme broadband and ultra-robust, low latency connectivity and massive networking to support the Internet of Things (IoT). With IoT and machine- to-machine (M2M) communication becoming more widespread, there will be a growing need for networks that meet the needs of lower power, low data rate, and long battery life. It is noted that, in 5G, the nodes that can provide radio access functionality to a user equipment (i.e., similar to Node B in UTRAN or eNB in LTE) may be named gNB when built on NR radio and may be named NG-eNB when built on E-UTRA radio.

SUMMARY:

[0003] According to a first embodiment, a method may include transmitting, by an apparatus to a first network node, a user registration that indicates that a user is attached to a global system for mobile communication. The method may include receiving, from a second network node, an initial address message based on the user registration.

[0004] In a variant, the transmitting of the user registration may further comprise transmitting the user registration based on a visitor location register trigger or a mobile switching center server trigger. In a variant, the apparatus may comprise a global system for mobile communication visitor register or a mobile switching center server. In a variant, the first network node may include an interworking function node. In a variant, the second network node may comprise a media gateway control function.

[0005] According to a second embodiment, a method may include receiving, by an apparatus from a first network node, a user registration that indicates that a user is attached to a global system for mobile communication. The method may include sending, to a second network node, a request for the user registration, where the request may comprise information or one or more uniform resource indicators for the user. The method may include receiving, from the second network node, an invite message based on the user registration. The method may include sending, to the first network node, the invite message based on the user registration.

[0006] In a variant, the receiving of the user registration may comprise receiving the user registration based on a visitor location register trigger or a mobile switching center server trigger. In a variant, the first network node may comprise a global system for mobile communication visitor register or mobile switching center server. In a variant, the apparatus may comprise an interworking function node. In a variant, the second network node may comprise a future rail mobile communication system node or a mission critical push-to-talk server. In a variant, the method may further include storing a local binding, and performing a translation from a first set of identifiers to a second set of identifiers. In a variant, the method may further include creating a mapping to a mission critical compatible uniform resource indicator. In a variant, the one or more uniform resource indicators may comprise one or more functional aliases.

[0007] According to a third embodiment, a method may include receiving, by an apparatus from a network node, a request for a user registration that indicates that a user is attached to a global system for mobile communication, where the request may comprise information or one or more uniform resource indicators for the user. The method may include modifying a status of the user to available based on the request for the user registration. [0008] In a variant, the network node may comprise an interworking function node. In a variant, the method may comprise storing an Internet protocol address or other information related to the network node. In a variant, the apparatus may comprise a future rail mobile communication system node or a mission critical push-to-talk server. In a variant, the one or more uniform resource indicators may comprise one or more functional aliases.

[0009] A fourth embodiment may be directed to an apparatus including at least one processor and at least one memory comprising computer program code. The at least one memory and computer program code may be configured, with the at least one processor, to cause the apparatus at least to perform the method according to the first embodiment, the second embodiment, or the third embodiment, or any of the variants discussed above. [0010] A fifth embodiment may be directed to an apparatus that may include circuitry configured to cause the apparatus to perform the method according to the first embodiment, the second embodiment, or the third embodiment, or any of the variants discussed above. [0011] A sixth embodiment may be directed to an apparatus that may include means for performing the method according to the first embodiment, the second embodiment, or the third embodiment, or any of the variants discussed above. Examples of the means may include one or more processors, memory, and/or computer program codes for causing the performance of the operation. [0012] A seventh embodiment may be directed to a computer readable medium comprising program instructions stored thereon for causing an apparatus to perform at least the method according to the first embodiment, the second embodiment, or the third embodiment, or any of the variants discussed above. [0013] An eighth embodiment may be directed to a computer program product encoding instructions for causing an apparatus to perform at least the method according to the first embodiment, the second embodiment, or the third embodiment, or any of the variants discussed above. BRIEF DESCRIPTION OF THE DRAWINGS :

[0014] For proper understanding of example embodiments, reference should be made to the accompanying drawings, wherein:

[0015] Fig. 1 illustrates an example of registering a GSM user, according to some embodiments; [0016] Fig. 2 illustrates an example flow diagram of a method, according to some embodiments;

[0017] Fig. 3 illustrates an example flow diagram of a method, according to some embodiments;

[0018] Fig. 4 illustrates an example flow diagram of a method, according to some embodiments;

[0019] Fig. 5a illustrates an example block diagram of an apparatus, according to an embodiment; and

[0020] Fig. 5b illustrates an example block diagram of an apparatus, according to another embodiment.

DETAIFED DESCRIPTION:

[0021] It will be readily understood that the components of certain example embodiments, as generally described and illustrated in the figures herein, may be arranged and designed in a wide variety of different configurations. Thus, the following detailed description of some example embodiments of systems, methods, apparatuses, and computer program products for registering a GSM user is not intended to limit the scope of certain embodiments but is representative of selected example embodiments. [0022] The features, structures, or characteristics of example embodiments described throughout this specification may be combined in any suitable manner in one or more example embodiments. For example, the usage of the phrases “certain embodiments,” “some embodiments,” or other similar wording, throughout this specification refers to the fact that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment. Thus, appearances of the phrases “in certain embodiments,” “in some embodiments,” “in other embodiments,” or other similar wording, throughout this specification do not necessarily all refer to the same group of embodiments, and the described features, structures, or characteristics may be combined in any suitable manner in one or more example embodiments. In addition, the phrase “set of’ refers to a set that includes one or more of the referenced set members. As such, the phrases “set of,” “one or more of,” and “at least one of,” or equivalent phrases, may be used interchangeably. Further, “or” is intended to mean “and/or,” unless explicitly stated otherwise.

[0023] Additionally, if desired, the different functions or operations discussed below may be performed in a different order and/or concurrently with each other. Furthermore, if desired, one or more of the described functions or operations may be optional or may be combined. As such, the following description should be considered as merely illustrative of the principles and teachings of certain example embodiments, and not in limitation thereof.

[0024] GSM-railway (GSM-R) is a GSM-based communication system designed for railway use. A future rail mobile communication system (FRMCS) may refer to the successor 5G-based communication system in which a mission critical (MC) server provides point-to-point/private call and group call service. During the migration phase when both systems, e.g., MC and GSM-R, are up and simultaneously running in a geographic area, at least one system may have to provide point-to-point (p2p) (private calls) and group calls towards or from the other system. An interworking function (IWF) logical network element may implement the protocol translation between an MC system and a GSM-R system. MC may define a functional model for an application plane, e.g., a mission critical push-to-talk (MCPTT) service. MC may define a reference point for interworking with other existing systems like GSM-R similarly to IWF-1 for interworking with a land mobile radio (LMR) system. In the latter case, MPCTT identifiers (IDs) may be used to identify the calling and the called user. For example, the MCPTT user at the MCPTT client may initiate an MCPTT private call. The MCPTT client may send an MCPTT private call request towards the MCPTT server. The MCPTT private call request may include the MCPTT IDs corresponding to the calling MCPTT party and the called LMR party, and a session description protocol (SDP) offer containing one or more media types.

[0025] However, how the MCPTT client becomes aware of the LMR party identifier and its presence is not defined in MC specifications, e.g., it may be based on implementation or configuration done by the public safety or railway organisation. Similar issues exist for the interworking of GSM-R and MC systems. In addition, MC and GSM-R use different types of identifiers. Currently only those FRMCS (e.g., MCPTT) users that are registered and presented to the MCPTT server can initiate and receive MCPTT (private or group) calls. If a GSM-R user wants to initiate or receive calls to/from the FRMCS system, then the GSM-R user may have to be registered and presented to the MCPTT server by an interworking unit. The problem is that currently a GSM-R user cannot call (or be called by) an FRMCS user as GSM-R users are outside of FRMCS/MCPTT domain. Only those FRMCS users who are registered and presented to the MCPTT server can initiate and receive MCPTT private calls. Thus, if a GSM-R user wants to initiate or receive calls to/from FRMCS system, then the GSM-R user may have to be registered and presented to (and thus identified by) the MCPTT server beforehand.

[0026] Some embodiments described herein may provide for registering a GSM user. For example, according to some embodiments, a GSM-R user may be registered by the IWF in the MCPTT system (e.g., by forwarding a registration of the GSM-R users to an MCPTT server). If the GSM-R users are registered in an MCPTT server then both the GSM-R users can initiate voice and group calls toward MCPTT users and the MCPTT users can call GSM-R users as they may be presented as other MCPTT users. In certain embodiments, the information of mapping GSM-R users to MCPTT identifiers may be stored at the IWF.

[0027] In this way, certain embodiments may provide the same user experience for both FRMCS users and GSM-R users. For example, the FRMCS users can also select GSM-R users from a contact list and call them by pushing a call button as the target user’s functional number is already stored during the registration. If all active GSM-R users are registered into the FRMCS and MCPTT systems, then the MCPTT server can handle the user availability and can provide this information to the FRMCS users so that they can identify the GSM-R user’s status as MC users. In addition, in this way, the MCPTT server may not be modified due to GSM-R-MCPTT interworking as the MCPTT server may identify the GSM-R user registration as an MCPTT user registration. Also call initiation and reception may be the same as for MCPTT users. Similarly, no changes may be needed for a call to an MC user. Overall, the LMR interworking an MC call procedures may remain unchanged and may be reused. Furthermore, in this way, the registration performed via the IWF for GSM-R users may avoid routing of requests from the FRMCS system to GSM-R users which are not reachable. In addition, in this way, certain embodiments may enable, as part of the registration procedure, to create also a mapping of GSM-R to FRMCS uniform resource indicators (URIs) (e.g., functional aliases). No further changes to functional alias (FA) handling may have to be used and the LMR interworking mechanisms can be reused, once the mapping is created.

[0028] Fig. 1 illustrates an example 100 of registering a GSM user, according to some embodiments. As illustrated in Fig. 1, the example 100 may include a GSM-R UE, a GSM-R visitor location register (VLR) and/or mobile switching center server (MSS) (GSM-R VLR/MSS), a media gateway control function (MGCF), an IWF, a FRMCS server providing an MCPTT service (via a hosted MCPTT server), and a FRMCS client. [0029] As illustrated at 102, the GSM-R UE may send, to the GSM-R VLR/MSS, a GSM-R user registration. As illustrated at 104, the GSM-R VLR/MSS may send, to the IWF, a GSM-R user registration. For example, when a GSM-R user is attached to the GSM-R system, then either based on a VLR or home location register (HLR) trigger, the GSM-R VLR/MSS may send a notification to the IWF. As illustrated at 106, the IWF may create an MC identifier and store a GSM-R to MC ID mapping. For example, in certain embodiments, a local binding may be created and stored at the IWF, and the translation of GSM-R IDs to MCPTT IDs may be performed at the IWF. The IWF may be the entity that has knowledge about the GSM-R system details and may serve as a gatekeeper.

[0030] As illustrated at 108, the IWF may send, to the FRMCS server, a registration request. For example, the IWF may send a registration request to the relevant MCPTT server with user information. GSM-R URIs (e.g., functional alias(es)) may be provided at this operation, and a mapping to an MC compatible URI may also be created. A pre requisite may be that the GSM-R user is configured in a MCPTT server user database. As illustrated at 110, the FRMCS server may send, to the IWF, a registration response. For example, the MCPTT system may receive the registration request and may change the status of the user to available (e.g., registered or active). Further, the MCPTT server may also store the IP address and other details of the IWF from which the registration request was received in order to be able to send call setup requests towards the newly registered GSM-R user. MC user profiles may be dynamically updated with information related to newly registered users (e.g., that includes a list of MCPTT users that an MCPTT user is authorized to obtain presence information for and MCPTT IDs (corresponding to GSM-R IDs)). Similar to registration, a deregistration may revert the state of the GSM-R user, and may indicate its unavailability, which may be provided by some embodiments. [0031] As illustrated at 112 through 144, the MCPTT users can initiate private calls or group calls targeting the GSM-R user and the MCPTT server may send the call initiation requests to the IWF. The IWF may translate session initiation protocol (SIP) requests and may reply towards the GSM-R system. When the registered GSM-R user initiates a call towards an MCPTT user, the request may be sent to the IWF and subsequently the IWF may initiate the call request to the MCPTT system via SIP signaling. For instance, as illustrated at 112, the FRMCS client may send, to the FRMCS server, a call invite, which may be sent to the IWF at 114 and to the MGCF at 116. As illustrated at 118, the IWF may send, to the FRMCS server, a 100 trying message. As illustrated at 120, the MGCF may send, to the GSM-R VLR/MSS, an initial address message (IAM). The IAM message may be originally sent from the IWF. As illustrated at 122, the GSM-R VLR/MSS may send, to the MGCF, an address complete message (ACM). As illustrated at 124, the MGCF may send, to the IWF, a 180 ringing message, which may be sent to the FRMCS server at 126 and the FRMCS client at 128. As illustrated at 130, the GSM-R VLR/MSS may send, to the MGCF, a call progress message (CPG). As illustrated at 132, the MGCF may send, to the IWF, a 183 session progress message, which may be sent to the FRMCS server at 134 and to the FRMCS client at 136. As illustrated at 138, the GSM-R VLR/MSS may send, to the MGCF, an answer. As illustrated at 140, the MGCF may send, to the IWF, a 200 Ok message, which may be sent to the FRMCS server at 142 and to the FRMCS client at 144.

[0032] As described above, in MC with respect to the IWF, the MCPTT/FRMCS user may be able to call a GSM-R user, but just by dialing a GSM-R mobile subscriber international subscriber director number (MSISDN) or GSM-R functional number. When the call is initiated, an FRMCS user may not know about the user availability or about the registration status of the GSM-R functional number. Without certain embodiments described herein, FRMCS users may have to dial digits and/or dial the GSM-R user’ s functional number and wait for the call to be routed to the GSM-R system and the GSM-R system may check the user availability and connect the call or reject it towards the FRMCS system. Also the GSM-R system would have to check whether the dialed number is correct or not, so an incorrect number can be rejected only after the call is routed to GSM-R system.

[0033] Thus, certain embodiments described above, and elsewhere herein, may provide registration of a GSM-R user in a MC system. This may facilitate the MC system and/or users to determine the availability of a target GSM-R user. If the user is not available, then the FRMCS user can skip the call or the MCPTT server can reject it based on the target user availability information. This improves communications by providing for interworking between communications systems.

[0034] In addition, certain embodiments may provide certain functionality with minimal impact to existing systems, e.g., GSM-R and MC. For example, the GSM-R UE may not be impacted and the overall impact to GSM-R may be minimal, namely the IWF may interface towards MC and GSM-R. For the IWF to GSM-R interface, although in the example 100 the VLR/MSS and IWF may be interfaced, in certain embodiments, the HLR may be interfaced instead. For the IWF-MC interface, a registration message pair (request-response pair) and a deregistration message pair may be used.

[0035] Furthermore, the IWF may be between the GSM-R system and the FRMCS system. This node may be used for handling the GSM-R user’s registration. However, certain embodiments may use another network element with the registration-related messages routed towards the other node, whereas the call-related messages may have to be routed towards the IWF.

[0036] As described above, Fig. 1 is provided as an example. Other examples are possible, according to some embodiments.

[0037] Fig. 2 illustrates an example flow diagram of a method 200, according to some embodiments. For example, Fig. 2 may illustrate example operations of a network node (e.g., apparatus 10 illustrated in, and described with respect to, Fig. 5a), such as the

GSM-R VLR/MSS of Fig. 1. Some of the operations illustrated in Fig. 2 may be similar to some operations shown in, and described with respect to, Fig. 1.

[0038] In an embodiment, the method 200 may include, at 202, transmitting, to a first network node, a user registration that indicates that a user is attached to a global system for mobile communication, e.g., in a manner similar to that at 104 of Fig. 1. The method 200 may include, at 204, receiving, from a second network node, an initial address message based on the user registration, e.g., in a manner similar to that at 120 of Fig. 1. [0039] The method 200 illustrated in Fig. 2 may include one or more additional aspects described below or elsewhere herein. In some embodiments, the transmitting at 202 may include transmitting the user registration based on a VLR trigger or a MSS trigger. In some embodiments, the first network node may include an IWF. In some embodiments, the second network node may include a media gateway control function. [0040] As described above, Fig. 2 is provided as an example. Other examples are possible according to some embodiments.

[0041] Fig. 3 illustrates an example flow diagram of a method 300, according to some embodiments. For example, Fig. 3 may illustrate example operations of a network node (e.g., apparatus 10 illustrated in, and described with respect to, Fig. 5a), such as the IWF of Fig. 1. Some of the operations illustrated in Fig. 3 may be similar to some operations shown in, and described with respect to, Fig. 1.

[0042] In an embodiment, the method 300 may include, at 302, receiving, from a first network node, a user registration that indicates that a user is attached to a global system for mobile communication, e.g., in a manner similar to that 104 of Fig. 1. The method 300 may include, at 304, sending, to a second network node, a request for the user registration, e.g., in a manner similar to that at 108 of Fig. 1. The request may include information or one or more uniform resource indicators for the user. The method 300 may include, at 306, receiving, from the second network node, an invite message based on the user registration. The method 300 may include, at 308, sending, to the first network node, the invite message based on the user registration, e.g., in a manner similar to that 116 and/or 120 of Fig. 1.

[0043] The method 300 illustrated in Fig. 3 may include one or more additional aspects described below or elsewhere herein. In some embodiments, the receiving at 302 may include receiving the user registration based on a VLR trigger or a MSS trigger. In some embodiments, the first network node may include a GSM-R VLR/MSS. In some embodiments, the second network node may include a FRMCS node or a MCPTT server. In some embodiments, the method 300 may further include storing a local binding, and performing a translation from a first set of identifiers to a second set of identifiers (e.g., from GSM-R IDs to MCPTT IDs). In some embodiments, the method 300 may include creating a mapping to an MC compatible uniform resource indicator.

In some embodiments, the one or more uniform resource indicators may include one or more functional aliases.

[0044] As described above, Fig. 2 is provided as an example. Other examples are possible according to some embodiments. [0045] Fig. 4 illustrates an example flow diagram of a method 400, according to some embodiments. For example, Fig. 4 may illustrate example operations of a network node (e.g., apparatus 10 illustrated in, and described with respect to, Fig. 5a), such as an FRMCS server that provides an MCPTT service via a MCPTT server. Some of the operations illustrated in Fig. 4 may be similar to some operations shown in, and described with respect to, Fig. 1.

[0046] In an embodiment, the method 400 may include, at 402, receiving, from a network node, a request for a user registration that indicates that a user is attached to a global system for mobile communication, e.g., in a manner similar to that at 108 of Fig. 1. The request may include information or one or more uniform resource indicators for the user. The method 400 may include, at 404, modifying a status of the user to available based on the request for the user registration.

[0047] The method 400 illustrated in Fig. 4 may include one or more additional aspects described below or elsewhere herein. In some embodiments, the network node may include an IWF. In some embodiments, the method 400 may include storing an Internet protocol (IP) address or other information related to the network node. In some embodiments, the method 400 may include sending a response to the network node associated with the request. In some embodiments, the one or more uniform resource indicators may include one or more functional aliases. [0048] As described above, Fig. 4 is provided as an example. Other examples are possible according to some embodiments.

[0049] Fig. 5a illustrates an example of an apparatus 10 according to an embodiment. In an embodiment, apparatus 10 may be a node, host, or server in a communications network or serving such a network. For example, apparatus 10 may be a network node (e.g., a GSM-R VLR/MSS, an MGCF, an IWF, an FRMCS server, or an MCPTT server), satellite, base station, a Node B, an evolved Node B (eNB), 5GNode B or access point, next generation Node B (NG-NB or gNB), and/or a WLAN access point, associated with a radio access network, such as a LTE network, 5G or NR. In some example embodiments, apparatus 10 may be an eNB in LTE or gNB in 5G.

[0050] It should be understood that, in some example embodiments, apparatus 10 may be comprised of an edge cloud server as a distributed computing system where the server and the radio node may be stand-alone apparatuses communicating with each other via a radio path or via a wired connection, or they may be located in a same entity communicating via a wired connection. For instance, in certain example embodiments where apparatus 10 represents a gNB, it may be configured in a central unit (CU) and distributed unit (DU) architecture that divides the gNB functionality. In such an architecture, the CU may be a logical node that includes gNB functions such as transfer of user data, mobility control, radio access network sharing, positioning, and/or session management, etc. The CU may control the operation of DU(s) over a front-haul interface. The DU may be a logical node that includes a subset of the gNB functions, depending on the functional split option. It should be noted that one of ordinary skill in the art would understand that apparatus 10 may include components or features not shown in Fig. 5a. [0051] As illustrated in the example of Fig. 5a, apparatus 10 may include a processor

12 for processing information and executing instructions or operations. Processor 12 may be any type of general or specific purpose processor. In fact, processor 12 may include one or more of general-purpose computers, special purpose computers, microprocessors, digital signal processors (DSPs), field-programmable gate arrays (FPGAs), application-specific integrated circuits (ASICs), and processors based on a multi-core processor architecture, as examples. While a single processor 12 is shown in Fig. 5a, multiple processors may be utilized according to other embodiments. For example, it should be understood that, in certain embodiments, apparatus 10 may include two or more processors that may form a multiprocessor system (e.g., in this case processor 12 may represent a multiprocessor) that may support multiprocessing. In certain embodiments, the multiprocessor system may be tightly coupled or loosely coupled (e.g., to form a computer cluster).

[0052] Processor 12 may perform functions associated with the operation of apparatus 10, which may include, for example, precoding of antenna gain/phase parameters, encoding and decoding of individual bits forming a communication message, formatting of information, and overall control of the apparatus 10, including processes related to management of communication or communication resources.

[0053] Apparatus 10 may further include or be coupled to a memory 14 (internal or external), which may be coupled to processor 12, for storing information and instructions that may be executed by processor 12. Memory 14 may be one or more memories and of any type suitable to the local application environment, and may be implemented using any suitable volatile or nonvolatile data storage technology such as a semiconductor-based memory device, a magnetic memory device and system, an optical memory device and system, fixed memory, and/or removable memory. For example, memory 14 can be comprised of any combination of random access memory (RAM), read only memory (ROM), static storage such as a magnetic or optical disk, hard disk drive (HDD), or any other type of non-transitory machine or computer readable media. The instructions stored in memory 14 may include program instructions or computer program code that, when executed by processor 12, enable the apparatus 10 to perform tasks as described herein.

[0054] In an embodiment, apparatus 10 may further include or be coupled to (internal or external) a drive or port that is configured to accept and read an external computer readable storage medium, such as an optical disc, USB drive, flash drive, or any other storage medium. For example, the external computer readable storage medium may store a computer program or software for execution by processor 12 and/or apparatus 10.

[0055] In some embodiments, apparatus 10 may also include or be coupled to one or more antennas 15 for transmitting and receiving signals and/or data to and from apparatus 10. Apparatus 10 may further include or be coupled to a transceiver 18 configured to transmit and receive information. The transceiver 18 may include, for example, a plurality of radio interfaces that may be coupled to the antenna(s) 15. The radio interfaces may correspond to a plurality of radio access technologies including one or more of GSM, NB-IoT, LTE, 5G, WLAN, Bluetooth, BT-LE, NFC, radio frequency identifier (RFID), ultrawideband (UWB), MulteFire, and the like. The radio interface may include components, such as filters, converters (for example, digital-to-analog converters and the like), mappers, a Fast Fourier Transform (FFT) module, and the like, to generate symbols for a transmission via one or more downlinks and to receive symbols (for example, via an uplink).

[0056] As such, transceiver 18 may be configured to modulate information on to a carrier waveform for transmission by the antenna(s) 15 and demodulate information received via the antenna(s) 15 for further processing by other elements of apparatus 10. In other embodiments, transceiver 18 may be capable of transmitting and receiving signals or data directly. Additionally or alternatively, in some embodiments, apparatus 10 may include an input and/or output device (I/O device).

[0057] In an embodiment, memory 14 may store software modules that provide functionality when executed by processor 12. The modules may include, for example, an operating system that provides operating system functionality for apparatus 10. The memory may also store one or more functional modules, such as an application or program, to provide additional functionality for apparatus 10. The components of apparatus 10 may be implemented in hardware, or as any suitable combination of hardware and software. [0058] According to some embodiments, processor 12 and memory 14 may be included in or may form a part of processing circuitry or control circuitry. In addition, in some embodiments, transceiver 18 may be included in or may form a part of transceiver circuitry. [0059] As used herein, the term “circuitry” may refer to hardware-only circuitry implementations (e.g., analog and/or digital circuitry), combinations of hardware circuits and software, combinations of analog and/or digital hardware circuits with software/firmware, any portions of hardware processor(s) with software (including digital signal processors) that work together to cause an apparatus (e.g., apparatus 10) to perform various functions, and/or hardware circuit(s) and/or processor(s), or portions thereof, that use software for operation but where the software may not be present when it is not needed for operation. As a further example, as used herein, the term “circuitry” may also cover an implementation of merely a hardware circuit or processor (or multiple processors), or portion of a hardware circuit or processor, and its accompanying software and/or firmware. The term circuitry may also cover, for example, a baseband integrated circuit in a server, cellular network node or device, or other computing or network device.

[0060] As introduced above, in certain embodiments, apparatus 10 may be a network node or RAN node, such as a base station, access point, Node B, eNB, gNB, WLAN access point, or the like.

[0061] According to certain embodiments, apparatus 10 may be controlled by memory 14 and processor 12 to perform the functions associated with any of the embodiments described herein, such as some operations illustrated in, or described with respect to, Figs. 1-4. For instance, apparatus 10 may be controlled by memory 14 and processor 12 to perform the methods of Figs. 2-4.

[0062] Fig. 5b illustrates an example of an apparatus 20 according to another embodiment. In an embodiment, apparatus 20 may be a node or element in a communications network or associated with such a network, such as a UE, GSM-R UE, FRMCS client, mobile equipment (ME), mobile station, mobile device, stationary device, IoT device, or other device. As described herein, a UE may alternatively be referred to as, for example, a mobile station, mobile equipment, mobile unit, mobile device, user device, subscriber station, wireless terminal, tablet, smart phone, IoT device, sensor or NB-IoT device, a watch or other wearable, a head-mounted display (HMD), a vehicle, a drone, a medical device and applications thereof (e.g., remote surgery), an industrial device and applications thereof (e.g., a robot and/or other wireless devices operating in an industrial and/or an automated processing chain context), a consumer electronics device, a device operating on commercial and/or industrial wireless networks, or the like. As one example, apparatus 20 may be implemented in, for instance, a wireless handheld device, a wireless plug-in accessory, or the like.

[0063] In some example embodiments, apparatus 20 may include one or more processors, one or more computer-readable storage medium (for example, memory, storage, or the like), one or more radio access components (for example, a modem, a transceiver, or the like), and/or a user interface. In some embodiments, apparatus 20 may be configured to operate using one or more radio access technologies, such as GSM, LTE, LTE-A, NR, 5G, WLAN, WiFi, NB-IoT, Bluetooth, NFC, MulteFire, and/or any other radio access technologies. It should be noted that one of ordinary skill in the art would understand that apparatus 20 may include components or features not shown in Fig. 5b. [0064] As illustrated in the example of Fig. 5b, apparatus 20 may include or be coupled to a processor 22 for processing information and executing instructions or operations. Processor 22 may be any type of general or specific purpose processor. In fact, processor 22 may include one or more of general-purpose computers, special purpose computers, microprocessors, digital signal processors (DSPs), field- programmable gate arrays (FPGAs), application-specific integrated circuits (ASICs), and processors based on a multi-core processor architecture, as examples. While a single processor 22 is shown in Fig. 5b, multiple processors may be utilized according to other embodiments. For example, it should be understood that, in certain embodiments, apparatus 20 may include two or more processors that may form a multiprocessor system (e.g., in this case processor 22 may represent a multiprocessor) that may support multiprocessing. In certain embodiments, the multiprocessor system may be tightly coupled or loosely coupled (e.g., to form a computer cluster).

[0065] Processor 22 may perform functions associated with the operation of apparatus 20 including, as some examples, precoding of antenna gain/phase parameters, encoding and decoding of individual bits forming a communication message, formatting of information, and overall control of the apparatus 20, including processes related to management of communication resources.

[0066] Apparatus 20 may further include or be coupled to a memory 24 (internal or external), which may be coupled to processor 22, for storing information and instructions that may be executed by processor 22. Memory 24 may be one or more memories and of any type suitable to the local application environment, and may be implemented using any suitable volatile or nonvolatile data storage technology such as a semiconductor-based memory device, a magnetic memory device and system, an optical memory device and system, fixed memory, and/or removable memory. For example, memory 24 can be comprised of any combination of random access memory (RAM), read only memory (ROM), static storage such as a magnetic or optical disk, hard disk drive (HDD), or any other type of non-transitory machine or computer readable media. The instructions stored in memory 24 may include program instructions or computer program code that, when executed by processor 22, enable the apparatus 20 to perform tasks as described herein.

[0067] In an embodiment, apparatus 20 may further include or be coupled to (internal or external) a drive or port that is configured to accept and read an external computer readable storage medium, such as an optical disc, USB drive, flash drive, or any other storage medium. For example, the external computer readable storage medium may store a computer program or software for execution by processor 22 and/or apparatus 20.

[0068] In some embodiments, apparatus 20 may also include or be coupled to one or more antennas 25 for receiving a downlink signal and for transmitting via an uplink from apparatus 20. Apparatus 20 may further include a transceiver 28 configured to transmit and receive information. The transceiver 28 may also include a radio interface (e.g., a modem) coupled to the antenna 25. The radio interface may correspond to a plurality of radio access technologies including one or more of GSM, LTE, LTE-A, 5G, NR, WLAN, NB-IoT, Bluetooth, BT-LE, NFC, RFID, UWB, and the like. The radio interface may include other components, such as filters, converters (for example, digital- to-analog converters and the like), symbol demappers, signal shaping components, an Inverse Fast Fourier Transform (IFFT) module, and the like, to process symbols, such as OFDMA symbols, carried by a downlink or an uplink.

[0069] For instance, transceiver 28 may be configured to modulate information on to a carrier waveform for transmission by the antenna(s) 25 and demodulate information received via the antenna(s) 25 for further processing by other elements of apparatus 20. In other embodiments, transceiver 28 may be capable of transmitting and receiving signals or data directly. Additionally or alternatively, in some embodiments, apparatus 20 may include an input and/or output device (I/O device). In certain embodiments, apparatus 20 may further include a user interface, such as a graphical user interface or touchscreen.

[0070] In an embodiment, memory 24 stores software modules that provide functionality when executed by processor 22. The modules may include, for example, an operating system that provides operating system functionality for apparatus 20. The memory may also store one or more functional modules, such as an application or program, to provide additional functionality for apparatus 20. The components of apparatus 20 may be implemented in hardware, or as any suitable combination of hardware and software. According to an example embodiment, apparatus 20 may optionally be configured to communicate with apparatus 10 via a wireless or wired communications link 70 according to any radio access technology, such as NR.

[0071] According to some embodiments, processor 22 and memory 24 may be included in or may form a part of processing circuitry or control circuitry. In addition, in some embodiments, transceiver 28 may be included in or may form a part of transceiving circuitry. As discussed above, according to some embodiments, apparatus 20 may be a UE, mobile device, mobile station, ME, IoT device and/or NB-IoT device, for example. According to certain embodiments, apparatus 20 may be controlled by memory 24 and processor 22 to perform the functions associated with any of the embodiments described herein, such as some operations illustrated in, or described with respect to, Figs. 1-4.

[0072] In some embodiments, an apparatus (e.g., apparatus 10 and/or apparatus 20) may include means for performing a method or any of the variants discussed herein, e.g., a method described with reference to Figs. 2-4. Examples of the means may include one or more processors, memory, and/or computer program code for causing the performance of the operation.

[0073] Therefore, certain example embodiments provide several technological improvements, enhancements, and/or advantages over existing technological processes. For example, one benefit of some example embodiments is interworking between, e.g., a GSM and an MC system. Accordingly, the use of some example embodiments results in improved functioning of communications networks and their nodes and, therefore constitute an improvement at least to the technological field of network communications, among others.

[0074] In some example embodiments, the functionality of any of the methods, processes, signaling diagrams, algorithms or flow charts described herein may be implemented by software and/or computer program code or portions of code stored in memory or other computer readable or tangible media, and executed by a processor. [0075] In some example embodiments, an apparatus may be included or be associated with at least one software application, module, unit or entity configured as arithmetic operation(s), or as a program or portions of it (including an added or updated software routine), executed by at least one operation processor. Programs, also called program products or computer programs, including software routines, applets and macros, may be stored in any apparatus-readable data storage medium and may include program instructions to perform particular tasks. [0076] A computer program product may include one or more computer-executable components which, when the program is run, are configured to carry out some example embodiments. The one or more computer-executable components may be at least one software code or portions of code. Modifications and configurations used for implementing functionality of an example embodiment may be performed as routine(s), which may be implemented as added or updated software routine(s). In one example, software routine(s) may be downloaded into the apparatus.

[0077] As an example, software or a computer program code or portions of code may be in a source code form, object code form, or in some intermediate form, and it may be stored in some sort of carrier, distribution medium, or computer readable medium, which may be any entity or device capable of carrying the program. Such carriers may include a record medium, computer memory, read-only memory, photoelectrical and/or electrical carrier signal, telecommunications signal, and/or software distribution package, for example. Depending on the processing power needed, the computer program may be executed in a single electronic digital computer or it may be distributed amongst a number of computers. The computer readable medium or computer readable storage medium may be a non-transitory medium.

[0078] In other example embodiments, the functionality may be performed by hardware or circuitry included in an apparatus (e.g., apparatus 10 or apparatus 20), for example through the use of an application specific integrated circuit (ASIC), a programmable gate array (PGA), a field programmable gate array (FPGA), or any other combination of hardware and software. In yet another example embodiment, the functionality may be implemented as a signal, such as a non-tangible means that can be carried by an electromagnetic signal downloaded from the Internet or other network. [0079] According to an example embodiment, an apparatus, such as a node, device, or a corresponding component, may be configured as circuitry, a computer or a microprocessor, such as single-chip computer element, or as a chipset, which may include at least a memory for providing storage capacity used for arithmetic operation(s) and/or an operation processor for executing the arithmetic operation(s). [0080] Example embodiments described herein apply equally to both singular and plural implementations, regardless of whether singular or plural wording is used in connection with describing certain embodiments. For example, an embodiment that describes operations of a single network node equally applies to embodiments that include multiple instances of the network node, and vice versa.

[0081] One having ordinary skill in the art will readily understand that the example embodiments as discussed above may be practiced with operations in a different order, and/or with hardware elements in configurations which are different than those which are disclosed. Therefore, although some embodiments have been described based upon these example embodiments, it would be apparent to those of skill in the art that certain modifications, variations, and alternative constructions would be apparent, while remaining within the spirit and scope of example embodiments.

PARTIAL GLOSSARY

[0082] GSM Global System for Mobile Communication

[0083] GSM-R GSM-Railway

[0084] FRMCS Future Railway Mobile Communication System

[0085] MCPTT Mission Critical Push To Talk

[0086] LMR Land Mobile Radio

[0087] p2p point-to-point

[0088] IWF Interworking Function

[0089] TETRA TErrestrial Trunked Radio