Adding more than one user registered to the same functional alias (FA) to a group call

Abstract

A method for initiating a group call in a mission critical push-to-talk (MCPTT) system. An apparatus receives a request for a group call associated with a mission critical MCPTT service 602 and determ

Description

FIELD

[0001] Various example embodiments relate generally to wireless networks and, more particularly, to provisioning group calls with support for adding more than one user registered to the same functional alias (FA) in a group call. BACKGROUND

[0002] Wireless networking provides significant advantages for user mobility. A user’s ability to remain connected while on the move provides advantages not only for the user, but also provides greater efficiency and productivity for society as a whole. As user expectations for, e.g., mission critical (MC) services and mission critical push-to-talk (MCPTT) group call functionalities, become more demanding, technology for wireless networking must also keep pace with such expectations. Accordingly, there is continuing interest in improving wireless networking technology. SUMMARY

[0003] In accordance with aspects of the present disclosure, a method includes receiving, by an apparatus, a request for a group call associated with a mission critical push-to-talk (MCPTT) service; determining, by the apparatus, the request includes a functional alias (FA) list, the FA list including one or more FAs to be invited to the group call; generating, based on the FA list, an MCPTT user identity (ID) list including one or more MCPTT IDs; and initiating the group call based on the MCPTT ID list.

[0004] In an aspect of the method, the generating the MCPTT ID list includes resolving the one or more FAs to the one or more MCPTT IDs.

[0005] In an aspect of the method, the resolving the one or more FAs to the one or more MCPTT IDs include for each FA of the one or more FAs, searching registration data for one or more MCPTT IDs registered to the respective FA in the FA list.

[0006] In an aspect of the method, the generating the MCPTT ID list includes determining an active MCPTT ID is registered to an FA in the FA list; and adding the active MCPTT ID to the MCPTT ID list, where the active MCPTT ID that is added is one of the one or more MCPTT IDs in the MCPTT ID list.

[0007] In an aspect of the method, the generating the MCPTT ID list is further based on a parameter that indicates whether adding more than one active MCPTT ID registered to the same FA is allowed or forbidden.

[0008] In an aspect of the method, the generating the MCPTT ID list includes determining a plurality of active MCPTT IDs are registered to an FA in the FA list; and adding, based on the parameter indicating that more than one MCPTT ID registered to the same FA is allowed, the plurality of active MCPTT IDs to the MCPTT ID list, where each active MCPTT ID of the plurality of active MCPTT IDs that is added is one of the one or more MCPTT IDs in the MCPTT ID list.

[0009] In an aspect of the method, the generating the MCPTT ID list includes determining a plurality of active MCPTT IDs are registered to an FA in the FA list; and selecting, based on the parameter indicating that more than one MCPTT ID registered to the same FA is forbidden, a single MCPTT ID from the plurality of active MCPTT IDs; and adding the single MCPTT ID to the MCPTT ID list, where the single MCPTT ID that is added is one of the one or more MCPTT IDs in the MCPTT ID list.

[0010] In an aspect of the method, the method further includes receiving, by the apparatus, from a server, MCPTT configuration data including the parameter that indicates whether adding more than one active MCPTT ID registered to the same FA is allowed or forbidden.

[0011] In accordance with aspects of the present disclosure, a method includes transmitting, by a user equipment (UE), a request for a group call associated with a mission critical push-to-talk (MCPTT) service, where the request includes a functional alias (FA) list that includes one or more FAs to be invited to the group call; receiving, by the UE, a response indicating a successful establishment of the group call; and joining the group call with one or more MCPTT clients, each of the one or more MCPTT clients registered to one of the one or more FAs in the FA list.

[0012] In an aspect of the method, the group call includes a maximum of one MCPTT client per FA in the FA list.

[0013] In an aspect of the method, the group call includes more than one MCPTT client associated with an FA in the FA list.

[0014] In accordance with aspects of the present disclosure, a method includes configuring, by an apparatus, mission critical push-to-talk (MCPTT) configuration data to include a parameter that indicates whether adding more than one active MCPTT user identify (ID) registered to the same functional alias (FA) is allowed or forbidden for a group call; and transmitting, by the apparatus to a server associated with an MCPTT service, the parameter.

[0015] In an aspect of the method, the MCPTT configuration data including the parameter that indicates whether adding more than one active MCPTT ID registered to the same FA is allowed or forbidden is part of MCPTT group configuration data.

[0016] In an aspect of the method, the MCPTT configuration data including the parameter that indicates whether adding more than one active MCPTT ID registered to the same FA is allowed or forbidden is part of MCPTT service configuration data.

[0017] In an aspect of the method, the method further includes receiving, by the apparatus from the server, a request for the parameter that indicates whether adding more than one active MCPTT ID registered to the same FA is allowed or forbidden.

[0018] According to some aspects, there is provided the subject matter of the independent claims. Some further aspects are defined in the dependent claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Some example embodiments will now be described with reference to the accompanying drawings.

[0020] FIG. 1 is a diagram of an example embodiment of wireless networking between a network system and a user equipment (UE), according to one illustrated aspect of the disclosure;

[0021] FIG. 2 is a diagram of an example embodiment of operations for provisioning a group call with support for adding more than one user registered to the same functional alias (FA) in the group call, according to one illustrated aspect of the present disclosure;

[0022] FIG. 3 is a flow diagram of example operations of a network apparatus that generates a mission critical push-to-talk (MCPTT) user identity (ID) list based on an FA list, according to one illustrated aspect of the present disclosure;

[0023] FIG. 4 is a diagram of an example information element indicating an FA list, according to one illustrated aspect of the present disclosure;

[0024] FIG. 5 is a diagram of an example of a portion of MCPTT configuration data, according to one illustrated aspect of the present disclosure;

[0025] FIG. 6 is a flow diagram of example operations of a network apparatus for provisioning a group call that supports adding one or more users registered to a same FA to the group call so provisioned, according to one illustrated aspect of the present disclosure;

[0026] FIG. 7 is a flow diagram of example operations of a user equipment (UE) that initiates a group call using an FA list to invite participants, according to one illustrated aspect of the present disclosure;

[0027] FIG. 8 is a flow diagram of example operations of a network apparatus that manages MCPTT configuration data for group calls that are initiated based on FAs, according to one illustrated aspect of the present disclosure; and

[0028] FIG. 9 is a diagram of example embodiment of components of a UE or of a network apparatus, according to one illustrated aspect of the present disclosure. DETAILED DESCRIPTION

[0029] In the following description, certain specific details are set forth in order to provide a thorough understanding of disclosed aspects. However, one skilled in the relevant art will recognize that aspects may be practiced without one or more of these specific details or with other methods, components, materials, etc. In other instances, well-known structures associated with transmitters, receivers, or transceivers have not been shown or described in detail to avoid unnecessarily obscuring descriptions of the aspects.

[0030] Reference throughout this specification to “one aspect” or “an aspect” means that a particular feature, structure, or characteristic described in connection with the aspect is included in at least one aspect. Thus, the appearances of the phrases “in one aspect” or “in an aspect” in various places throughout this specification are not necessarily all referring to the same aspect. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more aspects.

[0031] Embodiments described in the present disclosure may be implemented in wireless networking apparatuses, such as, without limitation, apparatuses utilizing Worldwide Interoperability for Microwave Access (WiMAX), Global System for Mobile communications (GSM, 2G), GSM EDGE radio access Network (GERAN), General Packet Radio Service (GRPS), Universal Mobile Telecommunication System (UMTS, 3G) based on basic wideband-code division multiple access (W-CDMA), high-speed packet access (HSPA), Long Term Evolution (LTE), LTE-Advanced, enhanced LTE (eLTE), 5G New Radio (5G NR), 5G Advance, 6G (and beyond) and 802.1 lax (Wi-Fi 6), among other wireless networking systems. The term £eLTE’ here denotes the LTE evolution that connects to a 5G core. LTE is also known as evolved UMTS terrestrial radio access (EUTRA) or as evolved UMTS terrestrial radio access network (EUTRAN).

[0032] Recent advancements in wireless communication technologies, such as 5G NR, can provide fast connectivity speeds, high bandwidths, and ultra-reliable, low-latency communications. These advancements can enable and / or enhance a wide variety of applications and / or services, such as mission critical (MC) services and / or applications.

[0033] The terms “service” and “application” may be used interchangeably herein, such that a description referring to one of the terms shall be treated as though the description also referred to the other term.

[0034] MC services are widely used, for example, by first responders, coast guards, transport companies such as railways and metro, and / or agencies that support public safety, protection, and / or disaster relief. MC services may include, MCPTT services, mission critical video calls, and mission critical data related operations. In some instances, these MC services may also be referred to as MCX services, where “X” may refer to push-to-talk (PTT), voice, and / or data.

[0035] The terms “MC services” and “MCX services” may be used interchangeably herein, such that a description referring to one of the terms shall be treated as though the description also referred to the other term.

[0036] MCPTT services may support private calls between two users. MCPTT services may also support communications between several users in group calls (e.g., ad hoc calls). In an MCPTT system, an MCPTT server may provision an MCPTT service to its users. Each user may be assigned an MCPTT user identity (MCPTT ID) for use within the MCPTT service. In other words, a MCPTT ID is a unique identifier of a user with the MCPTT service.

[0037] As used herein, the term “MCPTT server” may refer to an instance of an MCX service server that provides server application function(s) for an MCPTT service. As used herein, the term “MCPTT client” may refer to an instance of an MCX service client (e.g., at a UE) that provides client application function(s) for an MCPTT service. An MCPTT client may be a functional entity that acts as an agent for a user for all MCPTT application transactions. Once a user signs on to a MCPTT client using the user’s MCPTT ID, the user is reachable via the MCPTT client.

[0038] As used herein, the term “MCPTT ID” is an instance of an MCPTT service ID within a respective MCPTT service. The terms “MCPTT ID” and “MCPTT service ID” may be used interchangeably herein, such that a description referring to one of the terms shall be treated as though the description also referred to the other term.

[0039] As used herein, the term “functional alias (FA)” may refer to a user selectable (e.g., selected by an authorized user, an authoritative entity, a system) alias that is associated with the assignment or task of the user. A MCX user (e.g., an MCPTT user) may activate one or multiple FAs at the same time. The activation of the FA(s) may take place after the user has signed into an MCX service using the MCX user identity (e.g., MCPTT ID). An FA may be in any suitable format, for example, including numerical digits and / or letters. In other words, a MCPTT FA of user is an FA associated with the MCPTT ID and is designed to indicate a role / assignment / task that has been assigned to the user within the MCX service.

[0040] When an MCPTT user registers with an FA, the registration process may create a binding (connection or association) between the MCPTT user and the FA. The binding can be stored in an FA registration database, for example, at a memory of a server located within an MCPTT system. More specifically, an association or mapping between the MCPTT ID of the MCPTT user and the FA may be stored in the FA registration database. Thus, an MCPTT user registered to an FA means that the MCPTT ID of the MCPTT user is registered to the FA. Further, because an MCPTT client is a functional entity that acts as an agent for an MCPTT user, an MCPTT user registered to an FA also means that the MCPTT client is registered to the FA. As an example, a user may be assigned (e.g., a dispatcher, a swat team member) an FA associated with a task or mission performed by the user. An MCPTT client (e.g., at a device) used by the user may register with the FA, for example, by signing onto a server in an MCPTT system. Once the MCPTT client is registered with the FA, the MCPTT system may have the knowledge that the user is active in the MCPTT system and the MCPTT client is associated with the FA, or more specifically the MCPTT ID of the MCPTT client is active and registered with the FA.

[0041] As used herein, the terms “active MCPTT user” may refer to an MCPTT user who is actively using an MCPTT service (e.g., signed into the MCPTT service). Similarly, the terms “active MCPTT ID” may refer to an MCPTT ID of an MCPTT user that is actively using an MCPTT service. Further, the terms “active MCPTT client” may refer to an MCPTT client acting as an agent for an MCPTT user that is actively using an MCPTT service.

[0042] In some examples, the FA of an MCPTT user can be used as an alternative identity besides or instead of the MCPTT ID of the MCPTT user. For instance, FAs may be frequently used at railway companies, where railway personnels may call each other using their registered FA instead of using their MCPTT IDs. For example, a police officer may be assigned a FA associated with a role the officer performs as a member of a tactical team. While some MCPTT systems may handle operations related to FAs, these systems may not provide the same functionalities for services that are based on MCPTT ID(s) and services that are based on FA(s).

[0043] For example, 3rd Generation Partnership Project (3GPP) TS 23.379 V18.6.0 (2023-06) (“TS 23.379 document”) section 10.19, which is hereby incorporated by reference herein in its entirety, defines procedures for ad hoc group calls across a single MCPTT system, and associated functions such as emergency call, imminent peril call, broadcast call and others. However, these ad hoc group calls are all initiated based on MCPTT IDs and not FAs. For instance, section 10.19.2.1 of the TS 23.379 document specifies an ad hoc group call using a participant list provided by an initiator of the call or by an MCPTT server (that serves the ad hoc group call). When the participant list is provided by the initiator of the call, the participant list is a list of MCPTT IDs. When the participant list is provided by the MCPTT server, the MCPTT server may use criteria provided by the initiator of the call to determine the participant list along with its own criteria (e.g., a geographical location-based criteria) or local policies. The participant list determined by the MCPTT server is also a list of MCPTT IDs.

[0044] Aspects of the present disclosure provide techniques for initiating a group call with multiple FAs (e.g., an FA list) and inviting multiple MCPTT users registered to the same FA to the group call.

[0045] According to an aspect of the present disclosure, a network apparatus (e.g., an MCPTT server in an MCPTT system) may receive a request for a group call associated with an MCPTT service. In an example, the group call may be an ad hoc group call. The network apparatus may check whether the request includes an FA list. The FA list may include one or more FAs to be invited to the group call. The network apparatus may generate an MCPTT ID list based on the FA list. The MCPTT ID list may include one or more MCPTT IDs. The network apparatus may initiate the group call based on the MCPTT ID list.

[0046] In aspects, as part of generating the MCPTT ID list, the network apparatus may resolve the one or more FAs to the one or more MCPTT IDs. As part of resolving the one or more FAs to the one or more MCPTT IDs, for each FA in the FA list, the network apparatus may search registration data (e.g., an FA registration database) for MCPTT ID(s) registered to the respective FA. Stated differently, the network apparatus may perform FA resolution for the one or more FAs one-by-one and search for registered MCPTT ID(s) for the FA under resolution. The FA registration database may store bindings (associations or mappings) between FAs and MCPTT IDs that are registered to the respective FAs. In general, one or more MCPTT IDs may be registered to an FA, and an MCPTT ID may be registered to one or more FAs.

[0047] The search for MCPTT ID(s) registered to an FA may have one of several results. For example, the search result may indicate that no MCPTT ID is registered to the FA. Alternatively, the search result may indicate that a single MCPTT ID is registered to the FA. Yet alternatively, the search result may indicate that multiple MCPTT IDs are registered to the FA. Accordingly, in some instances, as part of generating the MCPTT ID list, the network apparatus may determine no active MCPTT ID is registered to an FA in the FA list, and thus may not make any modification to the MCPTT ID list. In some instances, as part of generating the MCPTT ID list, the network apparatus may determine a single active MCPTT ID is registered to an FA in the FA list and may add the active MCPTT ID to the MCPTT ID list, wherein the active MCPTT ID that is added is one of the one or more MCPTT IDs in the MCPTT ID list. In some instances, as part of generating the MCPTT ID list, the network apparatus may determine a plurality of active MCPTT IDs are registered to an FA in the FA list. In such instances, the network apparatus may generate the MCPTT ID list further based on a parameter (e.g., FA list control parameter) that indicates whether adding more than one active MCPTT ID registered to the same FA is allowed or forbidden. To that end, if the parameter indicates that more than one MCPTT ID registered to the same FA is allowed, the network apparatus may add the plurality of active MCPTT IDs to the MCPTT ID list, where each of the plurality of active MCPTT IDs that is added is one of the one or more MCPTT IDs in the MCPTT ID list. If, however, the parameter indicates that more than one MCPTT ID registered to the same FA is forbidden, the network apparatus may select a single MCPTT ID from the plurality of active MCPTT IDs and add the single MCPTT ID that is selected to the MCPTT ID list. The single MCPTT ID that is added is one of the one or more MCPTT IDs in the MCPTT ID list. The selection may be based on any suitable filtering criteria (e.g., location-based).

[0048] In aspects, the parameter that indicates whether adding more than one active MCPTT ID registered to the same FA is allowed or forbidden may be part of MCPTT configuration data. In aspects, the MCPTT configuration data is MCPTT group configuration data (e.g., related to MCPTT group management, group policy). In other aspects, the MCPTT configuration data is MCPTT service configuration data (e.g., related to MCPTT service management). In aspects, the MCPTT configuration data is stored at a server (different than the network apparats). Thus, the network apparatus may receive, from the server, the parameter as part of MCPTT configuration data. For instance, if the MCPTT configuration data is MCPTT group configuration data, the server is a group management server in the MCPTT system. Alternatively, if the MCPTT configuration data is MCPTT service configuration data, the server is a configuration management server in the MCPTT system.

[0049] In other aspects, the network apparatus may utilize a controlling server to resolve the FA(s) in the FA list. For instance, the FA registration database may be stored and managed by a controlling server in the MCPTT system. As such, the network apparatus may transmit (forward) the FA list to the controlling server, receive the one or more MCPTT IDs from the controlling server, and generate the MCPTT ID list based on the received MCPTT IDs.

[0050] According to an aspect of the present disclosure, a UE (eg., an MCPTT client or including a MCPTT client) may transmit a request for a group call associated with an MCPTT service, where the request may include an FA list. The FA list may include one or more FAs to be invited to the group call. In response, the UE may receive a response indicating a successful establishment of the group call. Subsequently, the UE may join the group call with one or more MCPTT clients, each registered to one of the one or more FAs in the FA list. In aspects, the group call may include a maximum of one MCPTT client per FA in the FA list (e.g., based on a parameter forbidding more than one active MCPTT ID (one MCPTT client or one MCPTT user) per FA to be added to the group call as discussed above). In other aspects, the group call may include more than one MCPTT client associated with an FA in the FA list (e.g., based on the parameter allowing more than one MCPTT ID (MCPTT client or MCPTT user) per FA to be added to the group call as discussed above).

[0051] According to an aspect of the present disclosure, a network apparatus (e.g., a management server in an MCPTT system) may configure MCPTT configuration data to include a parameter that indicates whether adding more than one active MCPTT ID registered to the same FA is allowed or forbidden for a group call. The network apparatus may transmit the parameter to a server (e.g., MCPTT server) associated with an MCPTT service. In aspects, the MCPTT configuration data including the parameter that indicates whether adding more than one active MCPTT ID registered to the same FA is allowed or forbidden may be part of MCPTT group configuration data. In other aspects, the MCPTT configuration data including the parameter that indicates whether adding more than one active MCPTT ID registered to the same FA is allowed or forbidden may be part of MCPTT service configuration data. In aspects, the network apparatus may receive, from the server, a request for the parameter that indicates whether adding more than one active MCPTT ID registered to the same FA is allowed or forbidden, wherein the parameter may be transmitted in response to the request. Such and other aspects will be described in more detail later herein.

[0052] Aspects of the present disclosure may provide several benefits. For example, adding an FA list to a group call request may enable a user to initiate a group call with multiple FAs using an FA list rather than being limited to using MCPTT IDs to initiate a group call. That is, instead of identifying each individual participant to be invited to the call, the user may initiate the group call using the FA to invite participants that are registered to that FA. Additionally, adding a parameter indicating whether more than one MCPTT user registered to the same FA is allowed to join a group call in MCPTT configuration data (e.g., MCPTT group configuration data or MCPTT service configuration data) can provide flexibility to MCPTT service operators in configuring group calls. The present disclosure may be applicable for any types of group calls (e.g., ad hoc group calls, preconfigured group calls, emergency group calls, and imminent peril group calls).

[0053] The present disclosure may use the term “serving network device” to refer to a network node or network device (or a portion thereof) that services a UE. As used herein, the terms “transmit to,” “receive from,” and “cooperate with,” (and their variations) include communications that may or may not involve communications through one or more intermediate devices or nodes. The term “acquire” (and its variations) includes acquiring in the first instance or reacquiring after the first instance. The term “connection” may mean a physical connection or a logical connection.

[0054] The present disclosure uses 5G NR as an example of a wireless network and may use smartphones and / or extended reality headsets as an example of UEs. It is intended and shall be understood that such examples are merely illustrative, and the present disclosure is applicable to other wireless networks and user equipment.

[0055] FIG. 1 is a diagram depicting an example of wireless networking between a network system 100 and a user equipment (UE) 150. The network system 100 may include one or more network nodes 120, one or more servers 110, and / or one or more network equipment 130 (e.g., test equipment). The network nodes 120 will be described in more detail below. As used herein, the term “network apparatus” may refer to any component of the network system 100, such as the server 110, the network node 120, the network equipment 130, any component(s) of the foregoing, and / or any other component(s) of the network system 100. Examples of network apparatuses include, without limitation, apparatuses implementing aspects of 5GNR, among others. The present disclosure describes embodiments related to 5G NR and embodiments that involve aspects defined by 3GPP. However, it is contemplated that embodiments relating to other wireless networking technologies are encompassed within the scope of the present disclosure.

[0056] The following description provides further details of examples of network nodes. In a 5G NR network, a gNodeB (also known as gNB) may include, e.g., a node that provides NR user plane and control plane protocol terminations towards the UE and that is connected via aNG interface to the 5G core (5GC), e.g., according to 3GPP TS 38.300 V16.6.0 (2021-06) section 3.2, which is hereby incorporated by reference herein.

[0057] A gNB supports various protocol layers, e.g., Layer 1 (LI) - physical layer, Layer 2 (L2), and Layer 3 (L3).

[0058] The layer 2 (L2) of NR is split into the following sublayers: Medium Access Control (MAC), Radio Link Control (RLC), Packet Data Convergence Protocol (PDCP) and Service Data Adaptation Protocol (SDAP), where, e.g.: o The physical layer offers to the MAC sublayer transport channels; o The MAC sublayer offers to the RLC sublayer logical channels; o The RLC sublayer offers to the PDCP sublayer RLC channels; o The PDCP sublayer offers to the SDAP sublayer radio bearers; o The SDAP sublayer offers to 5GC QoS flows; o Control channels include broadcast control channel (BCCH) and physical control channel (PCCH).

[0059] Layer 3 (L3) includes, e.g., radio resource control (RRC), e g., according to 3GPP TS 38.300 V16.6.0 (2021-06) section 6, which is hereby incorporated by reference herein.

[0060] A gNB central unit (gNB-CU) includes, e.g., a logical node hosting, e.g., radio resource control (RRC), service data adaptation protocol (SDAP), and packet data convergence protocol (PDCP) protocols of the gNB or RRC and PDCP protocols of the en-gNB, that controls the operation of one or more gNB distributed units (gNB-DUs). The gNB-CU terminates the Fl interface connected with the gNB-DU. A gNB-CU may also be referred to herein as a CU, a central unit, a centralized unit, or a control unit.

[0061] A gNB Distributed Unit (gNB-DU) includes, e.g., a logical node hosting, e.g., radio link control (RLC), media access control (MAC), and physical (PHY) layers of the gNB or en-gNB, and its operation is partly controlled by the gNB-CU. One gNB-DU supports one or multiple cells. One cell is supported by only one gNB-DU. The gNB-DU terminates the Fl interface connected with the gNB-CU. A gNB-DU may also be referred to herein as DU or a distributed unit.

[0062] As used herein, the term “network node” may refer to any of a gNB, a gNB-CU, or a gNB-DU, or any combination of them. A RAN (radio access network) node or network node such as, e.g., a gNB, gNB-CU, or gNB-DU, or parts thereof, may be implemented using, e.g., an apparatus with at least one processor and / or at least one memory with processor-readable instructions (“program”) configured to support and / or provision and / or process CU and / or DU related functionality and / or features, and / or at least one protocol (sub-)layer of a RAN (radio access network), e.g., layer 2 and / or layer 3. Different functional splits between the central and distributed unit are possible. An example of such an apparatus and components will be described in connection with FIG. 9 below.

[0063] The gNB-CU and gNB-DU parts may, e.g., be co-located or physically separated. The gNB-DU may even be split further, e.g., into two parts, e.g., one including processing equipment and one including an antenna. A central unit (CU) may also be called baseband unit / radio equipment controller / cloud-RAN / virtual-RAN (BBU / REC / C-RAN / V-RAN), open-RAN (O-RAN), or part thereof. A distributed unit (DU) may also be called remote radio head / remote radio unit / radio equipment / radio unit (RRH / RRU / RE / RU), or part thereof. Hereinafter, in various example embodiments of the present disclosure, a network node, which supports at least one of central unit functionality or a layer 3 protocol of a radio access network, may be, e.g., a gNB-CU. Similarly, a network node, which supports at least one of distributed unit functionality or a layer 2 protocol of the radio access network, may be, e.g., a gNB-DU.

[0064] A gNB-CU may support one or multiple gNB-DUs. A gNB-DU may support one or multiple cells and, thus, could support a serving cell for a user equipment (UE) or support a candidate cell for handover, dual connectivity, and / or carrier aggregation, among other procedures.

[0065] The UE 150 may be or include a wireless or mobile device, an apparatus with a radio interface to interact with a RAN (radio access network), a smartphone, an in-vehicle apparatus, an Internet of Things (loT) device, or a M2M device, among other types of user equipment. Such UE 150 may include: at least one processor; and at least one memory including program code; where the at least one memory and the computer program code are configured to, with the at least one processor, cause the apparatus at least to perform certain operations, such as, e.g., RRC connection to the RAN. An example of components of a UE will be described in connection with FIG. 9. In embodiments, the UE 150 may be configured to generate a message (e.g., including a cell ID) to be transmitted via radio towards a RAN (e.g., to reach and communicate with a serving cell). In embodiments, the UE 150 may generate and transmit and receive RRC messages containing one or more RRC PDUs (packet data units). Persons skilled in the art will understand RRC protocol as well as other procedures a UE may perform.

[0066] With continuing reference to FIG. 1, in the example of a 5G NR network, the network system 100 provides one or more cells, which define a coverage area of the network system 100. As described above, the network system 100 may include a gNB of a 5G NR network or may include any other apparatus configured to control radio communication and manage radio resources within a cell. As used herein, the term “resource” may refer to radio resources, such as a resource block (RB), a physical resource block (PRB), a radio frame, a subframe, a time slot, a sub-band, a frequency region, a sub-carrier, a beam, etc. In embodiments, the network node 120 may be called a base station.

[0067] FIG. 1 provides an example and is merely illustrative of a network system 100 and a UE 150. Persons skilled in the art will understand that the network system 100 includes components not illustrated in FIG. 1 and will understand that other user equipment may be in communication with the network system 100.

[0068] In aspects, the network system 100 may support MCPTT services (e.g., including private calls and group calls). For example, the server 110 may be an MCPTT server and the UE 150 may be an MCPTT client or include a MCPTT client. The MCPTT server may include an application, a set of applications, software, software modules, hardware components, or combination thereof that provides centralized support for MCPTT services. For example, the MCPTT server may execute an MCPTT server application. In some instances, the network system 100 may include one or more other servers 110, for example, including but not limited to, an FA controlling server, a group management server, and a configuration management server, to facilitate the MCPTT services.

[0069] The FA controlling server may include an application, a set of applications, software, software modules, hardware components, or combination thereof configured to manage FAs (e.g., FA registration, activation, and / or deactivations), maintain and track MCPTT IDs (of MCPTT users) that are registered to FAs (e.g., using a registration database that associates FAs and MCPTT IDs registered to the respective FAs), and resolve FAs to MCPTT IDs (e g., finding MCPTT IDs registered to a respective FA).

[0070] The group management server may include an application, a set of applications, software, software modules, hardware components, or combination thereof configured to manage MCPTT groups supported within an MCPTT service provider.

[0071] The configuration management server may include an application, a set of applications, software, software modules, hardware components, or combination thereof configured to manage MCPTT service configuration (e.g., service-related information that are not specific to a group) supported within the MCPTT service provider.

[0072] In aspects, the MCPTT server, the controlling server, the group management server, and the configuration management server may be software components implemented on the same computer system. In other aspects, each of the MCPTT server, the controlling server, the group management server, and the configuration management server may be implemented on a different computer system. In general, the MCPTT server, the controlling server, the group management server, and the configuration management server may be implemented in any suitable way on any suitable number of computer systems.

[0073] The MCPTT client may be an application, a set of applications, software, software modules, hardware components, or combination thereof configured to perform MCPTT client operations, for example, initiating, receiving, and / or participating in MCPTT calls (e.g., private calls and / or group calls). For example, the UE 150 may execute an MCPTT client application that is in communication with the MCPTT server application. As an example, the network system 100 may be in communication with other UEs 150 (multiple UE not shown in FIG. 1), each operating as an MCPTT client via execution of an MCPTT client application. Thus, the UE 150 (e.g., MCPTT client 1) may initiate a private call with another UE 150 (e.g., MCPTT client 2) or receive a private call from another UE 150. The UE 150 (e.g., MCPTT client 1) may also initiate a group call with multiple UEs 150 (e.g., an MCPTT client 2, an MCPTT client 3, and an MCPTT client 4) or receive a group call for communication with multiple UEs 150. In general, a group call can be among any suitable number MCPTT clients (e.g., 3, 4, 5, 6 or more)

[0074] In aspects, 3GPP allows more than one MCPTT user to register to the same FA. However, if a call is initiated with a called party FA, the FA resolution may identify a single MCPTT ID for the call. In other words, a call initiated using an FA will be set up as a private call even if the FA has multiple MCPTT users registered to the FA.

[0075] For example, the TS 3GPP 23.379 document section 10.7.2.2.1 defines the following MCPTT private call procedure for initiating a call using a called party FA.

[0076] In the 3 GPP MCPTT private call procedure, if an MCPTT server receives an MCPTT private call request and the MCPTT private call request includes an FA instead of an MCPTT ID as a called party, the MCPTT server may resolve the FA to the corresponding MCPTT ID for which the FA is active. For example, the MCPTT private call request is transmitted by MCPTT client 1, and the FA is resolved to an MCPTT ID of MCPTT client 2. The MCPTT server may determine whether the MCPTT private call request is authorized. For instance, the MCPTT server checks whether MCPTT client 1 is allowed to use the FA of MCPTT client 2 to set up a private call and whether MCPTT client 2 is allowed to receive a private call from MCPTT client 1 using the FA. If authorized, the MCPTT server proceeds with notifying MCPTT client 2 of the call. The MCPTT server may also perform various other checks as part of the authorization, for example, checking whether automatic commencement mode is authorized at MCPTT client 1 and MCPTT client 2.

[0077] Further, the TS 3GPP 23.379 document section 10.7.2.2.1 indicates that depending on implementation, the MCPTT server may apply additional call restrictions and decide whether the call is allowed to proceed with the resolved MCPTT ID (e.g., whether the MCPTT ID is within an allowed area of the FA). If the MCPTT server detects that the FA used as the target of the private call request is simultaneously active for multiple MCPTT users, then the MCPTT server may proceed by selecting an appropriate MCPTT ID based on some selection criteria. The selection of an appropriate MCPTT ID can be implementation-specific (e.g., based on the scenarios under which the calls are made). In some situations, there may be no suitable MCPTT ID for selection, and thus the call request may be rejected.

[0078] As discussed above, while ad hoc group call is defined in the TS 23.379 document, ad hoc group calls (or any other types of group call) may be initiated with a list of MCPTT IDs but not with a list of FAs.

[0079] The following table lists example ad hoc group call request information elements, 5 for example, as defined in Table 10.19.2.1-1 of the TS 23.379 document. In the status column, “M” denotes mandatory (i.e., the inclusion of the information element denoted for the respective row in a group call request is mandatory, and “O” denotes optional (i.e., the inclusion of the information element denoted for the respective row in a group call request is optional). Information Element Status Description MCPTT ID M The MCPTT ID of the calling party Functional alias O The functional alias of the calling party MCPTT ad hoc group ID (see NOTE 1) O The MCPTT group ID to be associated with the ad hoc group communication Encryption supported (see NOTE 2) O Indicates whether this ad hoc group call supports end-to-end encryption MCPTT ID list (see NOTE 3, NOTE 6, NOTE 7) O MCPTT IDs of the participants being invited for the ad hoc group call SDP offer M Offered Media parameters Implicit floor request (see NOTE 4) O When originating client requests the floor, this element shall be included Broadcast indicator (see NOTE 5) O Indicates that the ad hoc group call request is for a broadcast ad hoc group call Imminent peril indicator (see NOTE 5) O Indicates that the ad hoc group call request is an MCPTT imminent peril ad hoc group call Emergency Indicator (see NOTE 5) O Indicates that the ad hoc group call request is an MCPTT emergency ad hoc group call MCPTT ID list (see NOTE 3) O List of participants required to acknowledge the ad hoc group call before start of the audio transmission Location information O Location of the calling party. Criteria for determining the participants (see NOTE 6, NOTE 7) O Carries the details of criteria or meaningful label identifying the criteria or the combination of both which will be used by the MCPTT server for determining the participants e.g., it can be a location-based criteria to invite participants in a particular area Requested priority O Application priority level requested for this group call NOTE 1: If this information element is not included, the MCPTT server assigns an MCPTT ad hoc group ID to be used for the ad hoc group communication. This information element is returned to the calling party to use in the ad hoc group communication. If the request follows an ad hoc group for emergency alert, then this element must be present. NOTE 2: This information element is present and set to true only if this ad hoc group call is encrypted. When the ad hoc group call is initiated with participants provided by the initiator this acts as an indicator that subsequent requests follow targeting the individual participants and carrying the relevant key material. If this information element is set to false or not present, then this ad hoc group call is unencrypted. NOTE 3: This element is included only when the originating client sends the list of participants. NOTE 4: This element is included only when the originating client requests the floor. NOTE 5: If used, only one of these information elements is present. NOTE 6: Only one of these information elements is present. NOTE 7: If the request follows an ad hoc group for emergency alert, then this element is not present. Table 1 - Ad hoc group call request information elements

[0080] As shown in Table 1, an ad hoc group call can be initiated using a participant list (e.g., the information element “MCPTT ID list”) provided by an initiator of the call. Alternatively, an ad hoc group call can be initiated using a participant list provided by an MCPTT server (that serves the ad hoc group call) based on criteria (e.g., the information element “Criteria for determining the participants”) provided by the initiator of the call. In some instances, the MCPTT server may also determine the participant list along with its own criteria (e.g., a geographical location-based criteria) or local policies. The participant list determined by the MCPTT server is also a list of MCPTT IDs, for example, as described in the TS 23.379 document, section 10.19.2.19.

[0081] As discussed above, in certain scenarios, it may be desirable for an MCPTT user (e.g., a railway train driver, police dispatcher, etc.) to initiate a group call using FA(s) instead of MCPTT IDs.

[0082] Accordingly, the present disclosure provides techniques for initiating a group call with one or more, a plurality of, or multiple FAs (e.g., an FA list) and inviting multiple MCPTT users registered to the same FA to the group call. This can advantageously allow personnel of railway companies, public service enterprises, and / or other industries who may be used to initiating group calls using FAs to use MCPTT services for group calls (e.g., inviting multiple MCPTT users registered to the same FA to a group call).

[0083] The following will describe example operations for provisioning MCPTT services with group calls initiated based on FA(s). FIG. 2 shows example signals and operations of an MCPTT system provisioning a group call initiated using FA(s). FIG. 3 shows example operations of a network apparatus resolving FA(s) to MCPTT ID(s) FIG. 4 shows an example information element to be included in a group call request. FIG. 5 shows an example parameter to be configured in MCPTT configuration data. FIG. 6 shows example operations of a network apparatus (e.g., an MCPTT server providing MCPTT services), FIG. 7 shows example operations of a UE (e.g., an MCPTT client), and FIG. 8 shows example operations of a network apparatus (e.g., a management server supporting MCPTT services).

[0084] FIG. 2 is a diagram of an example embodiment of operations for provisioning a group call with support for adding more than one user registered to the same FA in the group call, according to one illustrated aspect of the present disclosure. It will be understood that a described signal may have associated operations and a described operation may have associated signals. Accordingly, a described signal may also involve an operation and a described operation may also involve a signal. Additionally, FIG. 2 will describe signals between and operations performed by various network components, such as those shown at the top of FIG. 2. Specifically, the components include an MCPTT client 1, an MCPTT client 2, an MCPTT client 3, an MCPTT client 4, an MCPTT server, and other server(s) in an MCPTT system. Each of the MCPTT clients 1-4 may correspond to an MCPTT user. For instance, MCPTT client 1 may correspond to an MCPTT user 1, MCPTT client 2 may correspond to an MCPTT user 2, and so on. In an aspect, each of the MCPTT clients 1, 2, 3, and 4 may be at a UE similar to the UE 150 of FIG. 1, and the MCPTT server and the other server(s) may correspond to servers similar to the server 110 of FIG. 1. The network components are illustrative, and it is contemplated that other components may be involved in the signals or may perform the operations. In some examples, each of the MCPTT clients 1, 2, 3, and 4, the MCPTT server, and the other server(s) may implement the operations using an apparatus with components as shown in FIG. 9. One or more of the following operations may be implemented in connection with the operations of the present disclosure, such as the examples discussed above with reference to FIG. 2.

[0085] At operation 211, the MCPTT client 1 transmits, and the MCPTT server receives a group call request to initiate a group call. The group call request may include information element(s) as shown above in Table 1. In aspects, the MCPTT client 1 may initiate the group call using FAs of participants to be invited to the group call. In one aspect, MCPTT client 1 may initiate the group call with MCPTT clients associated with a single FA. As will be discussed more fully below with reference to FIG. 4, the group call request may additionally include an information element (e.g., the information element 400 of FIG. 4) specifying an FA list that includes one or more FAs.

[0086] At operation 212, upon receiving the group call request, the MCPTT server performs an authorization based on the group call request. For instance, the MCPTT server may verify whether the MCPTT client 1 is authorized to initiate a group call. The MCPTT server may determine (or check) whether the group call request includes an FA list. If the MCPTT server determines that the group call request includes an FA list, the MCPTT server proceeds to determine whether the MCPTT client 1 is authorized to use an FA list to invite participants to a group call.

[0087] At operation 213, the MCPTT server transmits, and the MCPTT client 1 receives a group call request return message. The group call request return message may include an MCPTT group call identifier and an indication whether the group call is authorized or not. If the group call request is not authorized, the MCPTT server and the MCPTT client 1 may not proceed with the remaining operations. If, however, the group call request is authorized, the MCPTT server and the MCPTT client 1 may proceed to operation 214.

[0088] At operation 214, the MCPTT server generates, based on the FA list (in the group call request), a list of MCPTT IDs including one or more MCPTT IDs that are associated with an FA of the FA list. As part of resolving the one or more FAs to the one or more MCPTT IDs, the MCPTT server may search, for each FA in the FA list, registration data (e.g., an FA registration database) for one or more active MCPTT IDs registered to the respective FA. That is, the MCPTT server may perform FA resolution for the FAs one-by-one and search for active registered MCPTT ID(s) for the FA under resolution. The FA registration database may store associations (or mappings) between FAs and active MCPTT clients that are registered to the respective FAs. Mechanisms for FA resolution is discussed more fully below with reference to FIG. 3.

[0089] FIG. 3 is a flow diagram of example operations of a network apparatus that generates an MCPTT ID list based on an FA list, according to one illustrated aspect of the present disclosure. In an aspect, the network apparatus may correspond to the MCPTT server of FIG. 2. In some examples, the network apparatus may implement the operations using an apparatus with components as shown in FIG. 9. As illustrated, FIG. 2 includes a number of enumerated steps, but aspects of the operations in FIG. 2 may include additional steps before, after, and in between the enumerated steps. In aspects, one or more of the enumerated steps may be omitted or performed in a different order.

[0090] At block 302, the network apparatus receives a group call request, for example, corresponding to the operation 211 of FIG. 2. The group call request may include an FA list, denoted by FA list, of participants to be invited to the group call.

[0091] The network apparatus may resolve FA(s) in the FA list to one or more MCPTT IDs one-by-one. For example, FA list(i) may represent an i-th FA in the FA list, where FA list may include {FAo, FAi, FA2, ...}. The network apparatus may initialize the index i to 0 to resolve the first FA (e.g., FAo) in the FA list and may start with an empty MCPTT ID list.

[0092] At block 304, the network apparatus determines whether any active MCPTT ID is registered to FA list(i), for example, based on a search in an FA registration database. If the network apparatus determines that no active MCPTT ID is registered to FA_list(i), the network apparatus proceeds to block 306. At block 306, the network apparatus may not modify the MCPTT ID list. If, however, the network apparatus determines at least one active MCPTT ID is registered to F A Ji st( i) at block 304, the network apparatus proceeds to block 308.

[0093] At block 308, the network apparatus determines whether more than one active MCPTT ID is registered to FA list(i). If the network apparatus determines that a single active MCPTT ID is registered to FA_list(i), the network apparatus proceeds to block 310. At block 310, the network apparatus adds the single active MCPTT ID to the MCPTT ID list. If, however, the network apparatus determines more than one active MCPTT ID is registered to FA list(i) at block 308, the network apparatus proceeds to block 312.

[0094] At block 312, the network apparatus determines whether a parameter (e.g., an FA list control parameter) indicates adding more than one active MCPTT ID registered to the same FA is allowed. If the network apparatus determines that the parameter indicates adding more than one active MCPTT ID registered to the same FA is allowed, the network apparatus proceeds to block 314. At block 314, the network apparatus adds all of the active MCPTT IDs registered to FA list(i) to the MCPTT ID list. If, however, the network apparatus determines the parameter indicates adding more than one active MCPTT user registered to the same FA is not allowed (i.e., forbidden), the network apparatus proceeds to block 316.

[0095] At block 316, based on the parameter not allowing (i.e., forbidding) the adding of more than one active MCPTT user registered to the same FA, the network apparatus selects, based on certain selection criteria, one (single) MCPTT ID from the active MCPTT user(s) registered to FA list(i). The selection criteria may be any suitable criteria or filter, for example, depending on the particular tasks associated with the FA list. In some examples, the selection criteria may include a location-based criteria (e g., the location of the MCPTT user who initiated the group call). As an example, FAJist(i) may be an FA such as dispatcher@paris for dispatchers, and several dispatchers may be registered to this FA. A caller may initiate a call using the FA dispatcher@paris, and the selection may be based on a geographical location of the caller (which in one instance may be one of the dispatchers registered to the FA). If the call is initiated from a southern part of the city, then an active dispatcher registered with the FA and responsible for the southern part of the city is alerted (called). If, however, the call is initiated from a northern part of the city, then an active dispatcher registered with the FA and responsible for the southern part of the of city is alerted (called). Alternatively, the selection may be based on a station location. For instance, if the call is initiated from a certain train station, then an active station-responsible dispatcher is alerted (called). More specifically, a plurality of MCPTT IDs, each corresponding to one of the dispatchers, may be registered to FAJist(i), and the network apparatus may select a single MCPTT ID from the MCPTT IDs using a location filter based on a location of the caller (e.g., obtained from a user database). Another example of selection criteria includes, but is not limited to, time of the call initiation. For instance, dispatchers may work in shifts, e.g., from 6 AM to 2 PM and from 2 PM to 10 PM. Based on the time of the call initiation, different dispatchers can be involved in the group call. In general, the selection criteria may be based on an attribute related to the task or subtasks associated with the FA, an attribute associated with the call, and / or an attribute associated with the caller.

[0096] At block 318, after the selection, the network apparatus adds the single MCPTT ID from the selection to the MCPTT ID list.

[0097] After resolving FAJist(i), the network apparatus proceeds to block 320 to determine whether there are more FA(s) in the FA list. If there are more FA(s) in the FA list, the network apparatus proceeds to block 322 to increment the index i by 1 and return to block 304 to resolve the next FA in the FA list. The blocks 302-322 may be repeated until all FAs in the FA list are resolved.

[0098] In general, the network apparatus may determine whether there is any active MCPTT user (or MCPTT client) registered to a certain FA. If there is at least one active MCPTT user registered to the FA, the network apparatus may add an MCPTT ID of the active user based on the parameter (e.g., the FA list control parameter) that indicates whether adding more than one active registered MCPTT ID per FA to the group call is allowed.

[0099] Returning to FIG. 2, in aspects, at operation 214, the FA resolution can be performed at another server (shown by the other server(s)). For instance, the other server(s) may include a controlling server for performing FA resolution. Accordingly, the MCPTT server may transmit (forward) the FA list (in the received group call request) to the controlling server. In response, the MCPTT server may receive, from the controlling server, one or more MCPTT IDs resolved from the FA list. After receiving the one or more MCPTT IDs, the MCPTT server may generate the MCPTT ID list based on the received MCPTT ID(s).

[0100] In aspects, the parameter (e.g., FA list control parameter) that indicates whether adding more than one active MCPTT ID registered to the same FA is allowed or forbidden may be stored in certain MCPTT configuration data. FIG. 5 shows an example of such MCPTT configuration. In aspects, the MCPTT configuration may be managed and maintained by a server other than the MCPTT server. In one example, the other server(s) shown in FIG. 2 may include a group management server, and the MCPTT configuration data is MCPTT group configuration data. The group management server may be configured to store the FA list control parameter as part of MCPTT group configuration data and upon a query or request from the MCPTT server, the group management server may provide (transmit) the FA list control parameter to the MCPTT server. In another example, the other server(s) shown in FIG. 2 may include a configuration management server, and the MCPTT configuration data is MCPTT service configuration data. The configuration management server may be configured to store the FA list control parameter as part of MCPTT service configuration data and upon a query or request from the MCPTT server, the configuration management server may provide (transmit) the FA list control parameter to the MCPTT server.

[0101] After generating the MCPTT ID list, the MCPTT server may initiate the group call based on the MCPTT ID list by notifying MCPTT clients corresponding to the MCPTT ID(s) in the MCPTT ID list. In the illustrated example of FIG. 2, the MCPTT ID list may include three MCPTT IDs (e.g., corresponding to MCPTT client 2, MCPTT client 3, and MCPTT client 4) resolved from the FA list. In general, an FA list may be resolved to any suitable number of MCPTT IDs (e.g., 1, 2, 3, 4, 5, 6 or more).

[0102] As shown in FIG. 2, at operation 215a, the MCPTT server transmits, and the MCPTT client 2 receives the group call request. At operation 215b, the MCPTT server transmits, and the MCPTT client 3 receives the group call request. At operation 215c, the MCPTT server transmits, and the MCPTT client 4 receives the group call request. In some examples, when the MCPTT server transmits the group call request to a target participant (an MCPTT client), the MCPTT server may remove information (e.g., information elements) that is not required to be conveyed to the target participant. Additionally, the MCPTT server may transmit the MCPTT group call ID along with the group call request to the respective MCPTT clients.

[0103] At operation 216a, the receiving MCPTT client 2 (the called party) is notified about the incoming group call. At operation 216b, the receiving MCPTT client 3 (the called party) is notified about the incoming group call. At operation 216c, the receiving MCPTT client 4 (the called party) is notified about the incoming group call.

[0104] At operation 217a, in response to the group call request at operation 215a, the receiving MCPTT client 2 transmits, and the MCPTT server receives a response indicating an acceptance of the group call. At operation 217b, in response to the group call request at operation 215b, the receiving MCPTT client 3 transmits, and the MCPTT server receives a response indicating an acceptance of the group call. At operation 217c, in response to the group call request at operation 215c, the receiving MCPTT client 3 transmits, and the MCPTT server receives a response indicating an acceptance of the group call.

[0105] At operation 218, the MCPTT server transmits, and the (initiating) MCPTT client 1 receives a group call response indicating that the group call is successfully established.

[0106] In some examples, if the initiating MCPTT client 1 requests acknowledgement from the invited MCPTT clients, and the required MCPTT clients 2, 3, and / or 4 do not acknowledge the call setup within a configured time ("acknowledged call setup timeout"), then the MCPTT server may proceed with or abandon the call and then notify the initiating MCPTT client 1 that the acknowledgements did not include all required members, for example, according to a group call policy in a user profile configuration of the MCPTT client 1. The MCPTT server may notify the initiating the MCPTT client 1 of MCPTT clients (e g., MCPTT clients 2, 3, and / or 4) who did not acknowledge the group call request within the configured time. This notification may be sent to the initiating MCPTT client 1 by the MCPTT server more than once during the call, for example, when an MCPTT client joins or leaves the MCPTT group call. As shown in FIG. 2, at operation 219, the MCPTT server may transmit, and the MCPTT client 1 may receive a notification about the receiving MCPTT client 2, 3, and / or 4 joining the group call. The notification at operation 219 can be optional as shown by the dashed arrow.

[0107] At operation 220, the MCPTT server and the MCPTT clients 1-4 establish media plane and one or more floor control resources for the group call.

[0108] The signals and operations of FIG. 2 are merely illustrative, and variations are contemplated to be within the scope of the present disclosure. In embodiments, the signals and operations may include others not illustrated in FIG. 2. In embodiments, the signals and operations may not include every signal and operation illustrated in FIG. 2. In embodiments, the signals and operations may be implemented in a different order than that illustrated in FIG. 2. Such and other embodiments are contemplated to be within the scope of the present disclosure.

[0109] FIG. 4 is a diagram of an example information element indicating an FA list, according to one illustrated aspect of the present disclosure. As shown in FIG. 4, an information element 400 may include an FA list 402. The FA list 402 may indicate FAs of participants to be invited for a group call (e.g., an ad hoc group call). For instance, the FA list 402 may list one or more FAs. The FAs may be in any suitable format. In general, each FA can be in the form of numerical digits and / or letters. In aspects, the information element 400 may be part of the list of group call information elements shown in Table 1. In aspects, NOTE 3 shown in Table 1 may apply to the FA list 402. That is, the FA list 402 may be included only when the originating client sends the list of participants for a group call. In aspects, NOTE 6 shown in Table may apply to the FA list 402. That is, a group call request may include the FA list 402, an “MCPTT ID list,” or “Criteria for determining the participants” (e.g., for an MCPTT server to determine the participant list). In aspects, the information element 400 may be communicated between a server and a client of an MCPTT system. In aspects, the information element 400 may be included as part of the group call request at operation 211 of FIG. 2. In aspects, the information element 400 can be optional.

[0110] The information element 400 of FIG. 4 is merely illustrative, and variations are contemplated to be within the scope of the present disclosure.

[0111] FIG. 5 is a diagram of an example of a portion of MCPTT configuration data, according to one illustrated aspect of the present disclosure. As shown in FIG. 5, MCPTT configuration data 500 may include an FA control list parameter 502. The parameter 502 may indicate whether adding more than one active MCPTT user registered to the same FA is permitted for an MCPTT group (that participates in a group call). As discussed above, an MCPTT user registered to an FA means that the MCPTT ID of the MCPTT user is registered to the FA. Accordingly, the parameter 502 may indicate whether adding more than one active MCPTT ID registered to the same FA is permitted for a group call.

[0112] In FIG. 5, the symbol “Y” may denote "Yes", where the parameter 502 is to be configured to the functional entity denoted for the column, whereas the symbol "N" may denote "No", where the parameter 502 may not need to be configured to the functional entity denoted for the column. In aspects, the MCPTT configuration data 500 may be communicated between servers of an MCPTT system. In aspects, the MCPTT configuration data 500 may be included as part of the MCPTT group configuration described in Section A.4 of the TS 23.379 document. In other aspects, the MCPTT configuration data 500 may be included as part of the MCPTT service configuration data described in Section A.5 of the TS 23.379 document. In aspects, the parameter 502 may be used during FA resolution as discussed above with reference to FIG. 3.

[0113] The MCPTT configuration data 500 of FIG. 5 is merely illustrative, and variations are contemplated to be within the scope of the present disclosure.

[0114] FIG. 6 is a flow diagram of example operations of a network apparatus for provisioning a group call that supports adding one or more than one user registered to a same FA to the group call so provisioned, according to one illustrated aspect of the present disclosure. In an aspect, the network apparatus may correspond to the MCPTT server discussed above with reference to FIGS. 1-2. In some examples, the network apparatus may implement the operations using an apparatus with components as shown in FIG. 9. The operations of FIG. 6 may include similar mechanisms as discussed above with reference to FIGS. 1-5. As illustrated, FIG. 6 includes a number of enumerated steps, but aspects of the operations in FIG. 6 may include additional steps before, after, and in between the enumerated steps. In aspects, one or more of the enumerated steps may be omitted or performed in a different order.

[0115] At block 602, the network apparatus receives a request for a group call (e.g., ad hoc group call) associated with an MCPTT service.

[0116] At block 604, the network apparatus determines that the request includes an FA list. The FA list includes one or more FAs invited to the group call. In some instances, the group call request may include the FA list in an information element similar to the information element 400 discussed above with reference to FIG. 4.

[0117] At block 606, the network apparatus generates, based on the FA list, an MCPTT user identity (ID) list including one or more MCPTT IDs. In aspects, as part of generating the MCPTT ID, the network apparatus resolves the one or more FAs to the one or more MCPTT IDs. In aspects, as part of resolving the one or more FAs to the one or more MCPTT IDs, the network apparatus, for each FA of the one or more FAs, searches registration data (e.g., an FA registration database) for one or more MCPTT IDs registered to the respective FA in the FA list.

[0118] In aspects, as part of generating the MCPTT ID list at block 606, the network apparatus determines an active MCPTT ID is registered to an FA in the FA list and adds the active MCPTT ID to the MCPTT ID list, where the active MCPTT ID that is added is one of the one or more MCPTT IDs in the MCPTT ID list.

[0119] In aspects, the network apparatus may generate the MCPTT ID list at block 606 further based on a parameter that indicates whether adding more than one active MCPTT ID registered to the same FA is allowed or forbidden. In aspects, as part of generating the MCPTT ID list, the network apparatus determines a plurality of active MCPTT IDs are registered to an FA in the FA list. The network apparatus further adds, based on the parameter indicating that more than one MCPTT ID registered to the same FA is allowed, all of the plurality of active MCPTT IDs to the MCPTT ID list, where each of the plurality of active MCPTT IDs that is added is one of the one or more MCPTT IDs in the MCPTT ID list. In aspects, as part of generating the MCPTT ID list, the network apparatus determines a plurality of active MCPTT IDs registered to an FA in the FA list. The network apparatus further selects, based on the parameter indicating that more than one MCPTT ID registered to the same FA is forbidden, a single MCPTT ID from the plurality of active MCPTT IDs. The selection can be based on any suitable selection criteria or filter. The network apparatus further adds the single active MCPTT ID to the MCPTT ID list, where the single active MCPTT ID that is added is one of the one or more MCPTT IDs in the MCPTT ID list.

[0120] .At block 608, the network apparatus initiates the group call based on the MCPTT ID list. As part of initiating the group call, the network apparatus may transmit the group call request to each MCPTT client corresponding to the one or more MCPTT IDs in the MCPTT ID list, for example, as discussed above with reference to operations 215a-215c. Upon receiving a response from each of MCPTT clients, the network apparatus may respond to the group call request by transmitting a response indicating that the group call is successfully established, for example, as discussed above with reference to operations 216a- 216c and 217. Subsequently, the network apparatus may further establish a media plane and floor control resource(s) for the group call.

[0121] In aspects, the network apparatus further receives, from a server (e.g., a group management server or a configuration manage server), MCPTT configuration data including the parameter that indicates whether adding more than one active MCPTT ID registered to the same FA is allowed or forbidden. For example, the MCPTT configuration may be configured as discussed above with reference to FIG. 5

[0122] FIG. 7 is a flow diagram of example operations of a user equipment (UE) that initiates a group call using an FA list to invite participants, according to one illustrated aspect of the present disclosure. In an aspect, the UE may correspond to the UE 150 discussed above with reference to FIG. 1 and / or an initiating MCPTT client (e.g., MCPTT client 1) discussed above with reference to FIG. 2. In some examples, the UE may implement the operations using an apparatus with components as shown in FIG. 9. The operations of FIG. 7 may include similar mechanisms as discussed above with reference to FIGS. 1-5. As illustrated, FIG. includes a number of enumerated steps, but aspects of the operations in FIG. 7 may include additional steps before, after, and in between the enumerated steps. In aspects, one or more of the enumerated steps may be omitted or performed in a different order.

[0123] At block 702, the UE transmits a request for a group call associated with an MCPTT service (e.g., to an MCPTT server). The request includes an FA including one or more FAs to be invited to the group call. In some instances, the group call request may include the FA list in an information element similar to the information element 400 discussed above with reference to FIG. 4.

[0124] At block 704, the UE receives (e.g., from the MCPTT server) a response indicating a successful establishment of the group call.

[0125] At block 706, the UE joins the group call with one or more MCPTT clients, where each of the one or more MCPTT clients is registered to one of the one or more FAs in the FA list.

[0126] In aspects, the group call includes a maximum of one MCPTT user per FA in the FA list, for example, based on a configuration parameter indicating adding more than one active MCPTT ID (one MCPTT client or one MCPTT user) registered to the same FA is forbidden as discussed above with reference to FIG. 5. In other aspects, the group call includes more than one MCPTT user associated with an FA in the FA list, for example, based on a configuration parameter indicating adding more than one active MCPTT ID (one MCPTT client or one MCPTT user) registered to the same FA is allowed as discussed above with reference to FIG. 5.

[0127] FIG. 8 is a flow diagram of example operations of a network apparatus that manages MCPTT configuration data for group calls that are initiated based on FAs, according to one illustrated aspect of the present disclosure. In an aspect, the network apparatus may correspond to an MCPTT group management server or an MCPTT configuration management server discussed above with reference to FIGS. 1-2. In some examples, the network apparatus may implement the operations using an apparatus with components as shown in FIG. 9. The operations of FIG. 8 may include similar mechanisms as discussed above with reference to FIG. 1-5. As illustrated, FIG. 8 includes a number of enumerated steps, but aspects of the operations in FIG. 8 may include additional steps before, after, and in between the enumerated steps. In aspects, one or more of the enumerated steps may be omitted or performed in a different order.

[0128] At block 802, the network apparatus configures MCPTT configuration data with a parameter that indicates whether adding more than one active MCPTT ID registered to the same FA is allowed or forbidden for a group call. For example, the MCPTT configuration data may be similar to the MCPTT configuration data 500 discussed above with reference to FIG. 5. In aspects, the MCPTT configuration data having the parameter that indicates whether adding more than one active MCPTT ID registered to the same FA is allowed or forbidden is part of MCPTT group configuration data. In aspects, the MCPTT configuration data having the parameter that indicates whether adding more than one active MCPTT ID registered to the same FA is allowed or forbidden is part of MCPTT service configuration data.

[0129] At block 804, the network apparatus transmits, to a server (e.g., an MCPTT server) associated with an MCPTT service, the parameter or the configuration data having the parameter.

[0130] In aspects, the network apparatus further receives, from the server, a request for the parameter that indicates whether adding more than one active MCPTT ID registered to the same FA is allowed or forbidden.

[0131] Referring now to FIG. 9, there is shown a block diagram of example components of a UE or a network apparatus. The apparatus includes an electronic storage 910, a processor 920, a memory 950, and a network interface 940. The various components may be communicatively coupled with each other. The processor 920 may be and may include any type of processor, such as a single-core central processing unit (CPU), a multi-core CPU, a microprocessor, a digital signal processor (DSP), a System-on-Chip (SoC), or any other type of processor. The memory 950 may be a volatile type of memory, e.g., RAM, or a nonvolatile type of memory, e.g., NAND flash memory. The memory 950 includes processor-readable instructions that are executable by the processor 920 to cause the apparatus to perform various operations, including those mentioned herein, such as the operations of FIGS. 3-9.

[0132] The electronic storage 910 may be and include any type of electronic storage used for storing data, such as hard disk drive, solid state drive, and / or optical disc, among other types of electronic storage. The electronic storage 910 stores processor-readable instructions for causing the apparatus to perform its operations and stores data associated with such operations, such as storing data relating to 5G NR standards, among other data. The network interface 940 may implement wireless networking technologies such as 5G NR and / or other wireless networking technologies.

[0133] The components shown in FIG. 9 are merely examples, and persons skilled in the art will understand that an apparatus includes other components not illustrated and may include multiples of any of the illustrated components. Such and other embodiments are contemplated to be within the scope of the present disclosure.

[0134] Further embodiments of the present disclosure include the following examples.

[0135] Example 1.1 A method comprising: receiving, by an apparatus, a request for a group call associated with a mission critical push-to-talk (MCPTT) service; determining, by the apparatus, the request includes a functional alias (FA) list, the FA list including one or more FAs to be invited to the group call; generating, based on the FA list, an MCPTT user identity (ID) list including one or more MCPTT IDs; and initiating the group call based on the MCPTT ID list.

[0136] Example 1.2. The method of Example 1.1, wherein the generating the MCPTT ID list comprises: resolving the one or more FAs to the one or more MCPTT IDs.

[0137] Example 1.3. The method of Example 1.2, wherein the resolving the one or more FAs to the one or more MCPTT IDs comprises: for each FA of the one or more FAs, searching registration data for one or more MCPTT IDs registered to the respective FA in the FA list.

[0138] Example 1.4. The method of Example 1.1, wherein the generating the MCPTT ID list comprises: determining an active MCPTT ID is registered to an FA in the FA list; and adding the active MCPTT ID to the MCPTT ID list, wherein the active MCPTT ID that is added is one of the one or more MCPTT IDs in the MCPTT ID list.

[0139] Example 1.5. The method of any one of Examples 1.1-1.4, wherein the generating the MCPTT ID list is further based on a parameter that indicates whether adding more than one active MCPTT ID registered to the same FA is allowed or forbidden.

[0140] Example 1.6 The method of Example 1.1, wherein the generating the MCPTT ID list comprises: determining a plurality of active MCPTT IDs are registered to an FA in the FA list; and adding, based on a parameter indicating that more than one MCPTT ID registered to the same FA is allowed, the plurality of active MCPTT IDs to the MCPTT ID list, wherein each active MCPTT ID of the plurality of active MCPTT IDs that is added is one of the one or more MCPTT IDs in the MCPTT ID list.

[0141] Example 1.7. The method of Example 1.1, wherein the generating the MCPTT ID list comprises: determining a plurality of active MCPTT IDs are registered to an FA in the FA list; and selecting, based on a parameter indicating that more than one MCPTT ID registered to the same FA is forbidden, a single MCPTT ID from the plurality of active MCPTT IDs; and adding the single MCPTT ID to the MCPTT ID list, wherein the single MCPTT ID that is added is one of the one or more MCPTT IDs in the MCPTT ID list.

[0142] Example 1.8. The method of Example 1.1, further comprising: receiving, by the apparatus, from a server, MCPTT configuration data including a parameter that indicates whether adding more than one active MCPTT ID registered to the same FA is allowed or forbidden.

[0143] Example 2.1. A method comprising: transmitting, by a user equipment (UE), a request for a group call associated with a mission critical push-to-talk (MCPTT) service, wherein the request includes a functional alias (FA) list that includes one or more FAs to be invited to the group call; receiving, by the UE, a response indicating a successful establishment of the group call; and joining the group call with one or more MCPTT clients, each of the one or more MCPTT clients registered to one of the one or more FAs in the FA list.

[0144] Example 2.2. The method of Example 2.1, wherein the group call includes a maximum of one MCPTT client per FA in the FA list.

[0145] Example 2.3. The method of Example 2.1, wherein the group call includes more than one MCPTT client associated with an FA in the FA list.

[0146] Example 3.1. A method comprising: configuring, by an apparatus, mission critical push-to-talk (MCPTT) configuration data to include a parameter that indicates whether adding more than one active MCPTT user identify (ID) registered to the same functional alias (FA) is allowed or forbidden for a group call; and transmitting, by the apparatus to a server associated with an MCPTT service, the parameter.

[0147] Example 3.2. The method of Example 3.1, wherein the MCPTT configuration data including the parameter that indicates whether adding more than one active MCPTT ID registered to the same FA is allowed or forbidden is part of MCPTT group configuration data.

[0148] Example 3.3. The method ofExample 3.1, wherein the MCPTT configuration data including the parameter that indicates whether adding more than one active MCPTT ID registered to the same FA is allowed or forbidden is part of MCPTT service configuration data.

[0149] Example 3.4. The method ofExample 3.1, further comprising: receiving, by the apparatus from the server, a request for the parameter that indicates whether adding more than one active MCPTT ID registered to the same FA is allowed or forbidden.

[0150] Example 4.1 An apparatus comprising: at least one processor; and at least one memory storing instructions which, when executed by the processor, cause the apparatus at least to perform: receiving, by an apparatus, a request for a group call associated with a mission critical push-to-talk (MCPTT) service; determining, by the apparatus, the request includes a functional alias (FA) list, the FA list including one or more FAs to be invited to the group call; generating, based on the FA list, an MCPTT user identity (ID) list including one or more MCPTT IDs; and initiating the group call based on the MCPTT ID list.

[0151] Example 4.2. The apparatus of Example 4.1, wherein the generating the MCPTT ID list comprises: resolving the one or more FAs to the one or more MCPTT IDs.

[0152] Example 4.3. The apparatus of Example 4.2, wherein the resolving the one or more FAs to the one or more MCPTT IDs comprises: for each FA of the one or more FAs, searching registration data for one or more MCPTT IDs registered to the respective FA in the FA list.

[0153] Example 4.4. The apparatus of Example 4.1, wherein the generating the MCPTT ID list comprises: determining an active MCPTT ID is registered to an FA in the FA list; and adding the active MCPTT ID to the MCPTT ID list, wherein the active MCPTT ID that is added is one of the one or more MCPTT IDs in the MCPTT ID list.

[0154] Example 4.5. The apparatus of any one of Examples 4.1-4.4, wherein the generating the MCPTT ID list is further based on a parameter that indicates whether adding more than one active MCPTT ID registered to the same FA is allowed or forbidden.

[0155] Example 4.6 The apparatus of Example 4.1, wherein the generating the MCPTT ID list comprises: determining a plurality of active MCPTT IDs are registered to an FA in the FA list; and adding, based on a parameter indicating that more than one active MCPTT ID registered to the same FA is allowed, the plurality of active MCPTT IDs to the MCPTT ID list, wherein each active MCPTT ID of the plurality of active MCPTT IDs that is added is one of the one or more MCPTT IDs in the MCPTT ID list.

[0156] Example 4.7. The apparatus of Example 4.1, wherein the generating the MCPTT ID list comprises: determining a plurality of active MCPTT IDs are registered to an FA in the FA list; and selecting, based on a parameter indicating that more than one active MCPTT ID registered to the same FA is forbidden, a single MCPTT ID from the plurality of active MCPTT IDs; and adding the single MCPTT ID to the MCPTT ID list, wherein the single MCPTT ID that is added is one of the one or more MCPTT IDs in the MCPTT ID list.

[0157] Example 4.8. The apparatus of Example 4.1, wherein the at least one processor is further configured to at least perform: receiving, by the apparatus, from a server, MCPTT configuration data including a parameter that indicates whether adding more than one active MCPTT ID registered to the same FA is allowed or forbidden.

[0158] Example 5.1. An apparatus comprising: at least one processor; and at least one memory storing instructions which, when executed by the processor, cause the apparatus at least to perform: transmitting, by a user equipment (UE), a request for a group call associated with a mission critical push-to-talk (MCPTT) service, wherein the request includes a functional alias (FA) list that includes one or more FAs to be invited to the group call; receiving, by the UE, a response indicating a successful establishment of the group call; and joining the group call with one or more MCPTT clients, each of the one or more MCPTT clients registered to one of the one or more FAs in the FA list.

[0159] Example 5.2. The apparatus of Example 5.1, wherein the group call includes a maximum of one MCPTT client per FA in the FA list.

[0160] Example 5.3. The apparatus of Example 5.1, wherein the group call includes more than one MCPTT client associated with an FA in the FA list.

[0161] Example 6.1. An apparatus comprising: at least one processor; and at least one memory storing instructions which, when executed by the processor, cause the apparatus at least to perform: configuring, by an apparatus, mission critical push-to-talk (MCPTT) configuration data to include a parameter that indicates whether adding more than one active MCPTT user identify (ID) registered to the same functional alias (FA) is allowed or forbidden for a group call; and transmitting, by the apparatus to a server associated with an MCPTT service, the parameter.

[0162] Example 6.2. The apparatus of Example 6.1, wherein the MCPTT configuration data including the parameter that indicates whether adding more than one active MCPTT ID registered to the same FA is allowed or forbidden is part of MCPTT group configuration data.

[0163] Example 6.3. The apparatus of Example 6.1, wherein the MCPTT configuration data including the parameter that indicates whether adding more than one active MCPTT ID registered to the same FA is allowed or forbidden is part of MCPTT service configuration data.

[0164] Example 6.4. The apparatus of Example 6.1, wherein the at least one processor is further configured to at least perform: receiving, by the apparatus from the server, a request for the parameter that indicates whether adding more than one active MCPTT ID registered to the same FA is allowed or forbidden.

[0165] Example 7.1 An apparatus comprising: means for receiving, by an apparatus, a request for a group call associated with a mission critical push-to-talk (MCPTT) service; means for determining, by the apparatus, the request includes a functional alias (FA) list, the FA list including one or more FAs to be invited to the group call; means for generating, based on the FA list, an MCPTT user identity (ID) list including one or more MCPTT IDs; and means for initiating the group call based on the MCPTT ID list.

[0166] Example 7.2. The apparatus of Example 7.1, wherein the means for generating the MCPTT ID list comprises: means for resolving the one or more FAs to the one or more MCPTT IDs.

[0167] Example 7.3. The apparatus of Example 7.2, wherein the means for resolving the one or more FAs to the one or more MCPTT IDs comprises: for each FA of the one or more FAs, means for searching registration data for one or more MCPTT IDs registered to the respective FA in the FA list.

[0168] Example 7.4. The apparatus of Example 7.1, wherein the means for generating the MCPTT ID list comprises: means for determining an active MCPTT ID is registered to an FA in the FA list; and means for adding the active MCPTT ID to the MCPTT ID list, wherein the active MCPTT ID that is added is one of the one or more MCPTT IDs in the MCPTT ID list.

[0169] Example 7.5. The apparatus of any one of Examples 7.1-7.4, wherein the means for generating the MCPTT ID list is further based on a parameter that indicates whether adding more than one active MCPTT ID registered to the same FA is allowed or forbidden.

[0170] Example 7.6 The apparatus of Example 7.1, wherein the means for generating the MCPTT ID list comprises: means for determining a plurality of active MCPTT IDs are registered to an FA in the FA list; and means for adding, based on a parameter indicating that more than one active MCPTT ID registered to the same FA is allowed, the plurality of active MCPTT IDs to the MCPTT ID list, wherein each active MCPTT ID of the plurality of active MCPTT IDs that is added is one of the one or more MCPTT IDs in the MCPTT ID list.

[0171] Example 7.7. The apparatus of Example 7.1, wherein the means for generating the MCPTT ID list comprises: means for determining a plurality of active MCPTT IDs are registered to an FA in the FA list; and means for selecting, based on a parameter indicating that more than one active MCPTT ID registered to the same FA is forbidden, a single MCPTT ID from the plurality of active MCPTT IDs; and means for adding the single MCPTT ID to the MCPTT ID list, wherein the single MCPTT ID that is added is one of the one or more MCPTT IDs in the MCPTT ID list.

[0172] Example 7.8. The apparatus of Example 7.1, further comprising: means for receiving, by the apparatus, from a server, MCPTT configuration data including a parameter that indicates whether adding more than one active MCPTT ID registered to the same FA is allowed or forbidden.

[0173] Example 8.1. An apparatus comprising: means for transmitting, by a user equipment (UE), a request for a group call associated with a mission critical push-to-talk (MCPTT) service, wherein the request includes a functional alias (FA) list that includes one or more FAs to be invited to the group call; means for receiving, by the UE, a response indicating a successful establishment of the group call; and means for joining the group call with one or more MCPTT clients, each of the one or more MCPTT clients registered to one of the one or more FAs in the FA list.

[0174] Example 8.2. The apparatus of Example 8.1, wherein the group call includes a maximum of one MCPTT client per FA in the FA list.

[0175] Example 8.3. The apparatus of Example 8.1, wherein the group call includes more than one MCPTT client associated with an FA in the FA list.

[0176] Example 9.1. An apparatus comprising: means for configuring, by an apparatus, mission critical push-to-talk (MCPTT) configuration data to include a parameter that indicates whether adding more than one active MCPTT user identify (ID) registered to the same functional alias (FA) is allowed or forbidden for a group call; and means for transmitting, by the apparatus to a server associated with an MCPTT service, the parameter.

[0177] Example 9.2. The apparatus of Example 9.1, wherein the MCPTT configuration data including the parameter that indicates whether adding more than one active MCPTT ID registered to the same FA is allowed or forbidden is part of MCPTT group configuration data.

[0178] Example 9.3. The apparatus of Example 9.1, wherein the MCPTT configuration data including the parameter that indicates whether adding more than one active MCPTT ID registered to the same FA is allowed or forbidden is part of MCPTT service configuration data.

[0179] Example 9.4. The apparatus of Example 9.1, further comprising: means for receiving, by the apparatus from the server, a request for the parameter that indicates whether adding more than one active MCPTT ID registered to the same FA is allowed or forbidden.

[0180] Example 10. A non-transitory processor-readable medium including program code, which when executed by one or more processors, causes the one or more processors at least to perform the method of any one of Examples 1.1-1.8.

[0181] Example 11. A non-transitory processor-readable medium including program code, which when executed by one or more processors, causes the one or more processors at least to perform the method of any one of Examples 2.1-2.3.

[0182] Example 12. A non-transitory processor-readable medium including program code, which when executed by one or more processors, causes the one or more processors at least to perform the method of any one of Examples 3.1-3.4.

[0183] The embodiments and aspects disclosed herein are examples of the present disclosure and may be embodied in various forms. For instance, although certain embodiments herein are described as separate embodiments, each of the embodiments herein may be combined with one or more of the other embodiments herein. Specific structural and functional details disclosed herein are not to be interpreted as limiting, but as a basis for the claims and as a representative basis for teaching one skilled in the art to variously employ the present disclosure in virtually any appropriately detailed structure. Like reference numerals may refer to similar or identical elements throughout the description of the figures.

[0184] The phrases “in an aspect,” “in aspects,” “in various aspects,” “in some aspects,” or “in other aspects” may each refer to one or more of the same or different aspects in accordance with this present disclosure. The phrase “a plurality of’ may refer to two or more.

[0185] The phrases “in an embodiment,” “in embodiments,” “in various embodiments,” “in some embodiments,” or “in other embodiments” may each refer to one or more of the same or different embodiments in accordance with the present disclosure. A phrase in the form “A or B” means “(A), (B), or (A and B)” A phrase in the form “at least one of A, B, or C” means “(A); (B); (C); (A and B); (A and C); (B and C); or (A, B, and C) ”

[0186] Any of the herein described methods, programs, algorithms or codes may be converted to, or expressed in, a programming language or computer program. The terms “programming language” and “computer program,” as used herein, each include any language used to specify instructions to a computer, and include (but is not limited to) the following languages and their derivatives: Assembler, Basic, Batch files, BCPL, C, C+, C++, Delphi, Fortran, Java, JavaScript, machine code, operating system command languages, Pascal, Perl, PL1, Python, scripting languages, Visual Basic, metalanguages which themselves specify programs, and all first, second, third, fourth, fifth, or further generation computer languages. Also included are database and other data schemas, and any other metalanguages. No distinction is made between languages which are interpreted, compiled, or use both compiled and interpreted approaches. No distinction is made between compiled and source versions of a program. Thus, reference to a program, where the programming 5 language could exist in more than one state (such as source, compiled, object, or linked) is a reference to any and all such states. Reference to a program may encompass the actual instructions and / or the intent of those instructions.

[0187] While aspects of the present disclosure have been shown in the drawings, it is not intended that the present disclosure be limited thereto, as it is intended that the present 10 disclosure be as broad in scope as the art will allow and that the specification be read likewise. Therefore, the above description should not be construed as limiting, but merely as exemplifications of particular aspects. Those skilled in the art will envision other modifications within the scope and spirit of the claims appended hereto.

Claims

1. A method comprising:receiving, by an apparatus, a request for a group call associated with a mission critical push-to-talk (MCPTT) service;determining, by the apparatus, the request includes a functional alias (FA) list, the FA list including one or more FAs to be invited to the group call;generating, based on the FA list, an MCPTT user identity (ID) list including one or more MCPTT IDs; andinitiating the group call based on the MCPTT ID list.

2. The method of claim 1, wherein the generating the MCPTT ID list comprises: resolving the one or more FAs to the one or more MCPTT IDs.

3. The method of claim 2, wherein the resolving the one or more FAs to the one or more MCPTT IDs comprises:for each FA of the one or more FAs, searching registration data for one or more active MCPTT IDs registered to the respective FA in the FA list.

4. The method of claim 1, wherein the generating the MCPTT ID list comprises: determining an active MCPTT ID is registered to an FA in the FA list; and adding the active MCPTT ID to the MCPTT ID list, wherein the active MCPTT ID that is added is one of the one or more MCPTT IDs in the MCPTT ID list.

5. The method of any one of claims 1-4, wherein the generating the MCPTT ID list is further based on a parameter that indicates whether adding more than one active MCPTT ID registered to the same FA is allowed or forbidden.

6. The method of claim 1, wherein the generating the MCPTT ID list comprises: determining a plurality of active MCPTT IDs are registered to an FA in the FA list; andadding, based on a parameter indicating that more than one active MCPTT ID registered to the same FA is allowed, the plurality of active MCPTT IDs to the MCPTT IDlist, wherein each active MCPTT ID of the plurality of active MCPTT IDs that is added is one of the one or more MCPTT IDs in the MCPTT ID list.

7. The method of claim 1, wherein the generating the MCPTT ID list comprises: determining a plurality of active MCPTT IDs are registered to an FA in the FA list; andselecting, based on a parameter indicating that more than one active MCPTT ID registered to the same FA is forbidden, a single MCPTT ID from the plurality of active MCPTT IDs; andadding the single MCPTT ID to the MCPTT ID list, wherein the single MCPTT ID that is added is one of the one or more MCPTT IDs in the MCPTT ID list.

8. The method of claim 1, further comprising:receiving, by the apparatus, from a server, MCPTT configuration data including a parameter that indicates whether adding more than one active MCPTT ID registered to the same FA is allowed or forbidden.

9. A method comprising:transmitting, by a user equipment (UE), a request for a group call associated with a mission critical push-to-talk (MCPTT) service, wherein the request includes a functional alias (FA) list that includes one or more FAs to be invited to the group call;receiving, by the UE, a response indicating a successful establishment of the group call; andjoining the group call with one or more MCPTT clients, each of the one or more MCPTT clients registered to one of the one or more FAs in the FA list.

10. The method of claim 9, wherein the group call includes a maximum of one MCPTT client per FA in the FA list.

11. The method of claim 9, wherein the group call includes more than one MCPTT client associated with an FA in the FA list.

12. A method comprising:configuring, by an apparatus, mission critical push-to-talk (MCPTT) configuration data to include a parameter that indicates whether adding more than one active MCPTT user identify (ID) registered to the same functional alias (FA) is allowed or forbidden for a group call; andtransmitting, by the apparatus to a server associated with an MCPTT service, the parameter.

13. The method of claim 12, wherein the MCPTT configuration data including the parameter that indicates whether adding more than one active MCPTT ID registered to the same FA is allowed or forbidden is part of MCPTT group configuration data.

14. The method of claim 12, wherein the MCPTT configuration data including the parameter that indicates whether adding more than one active MCPTT ID registered to the same FA is allowed or forbidden is part of MCPTT service configuration data.

15. The method of claim 12, further comprising:receiving, by the apparatus from the server, a request for the parameter that indicates whether adding more than one active MCPTT ID registered to the same FA is allowed or forbidden.

16. An apparatus comprising:at least one processor; andat least one memory storing instructions which, when executed by the processor, cause the apparatus at least to perform the method of any one of claims 1-8.

17. An apparatus comprising:at least one processor; andat least one memory storing instructions which, when executed by the processor, cause the apparatus at least to perform the method of any one of claims 9-11.

18. An apparatus comprising:at least one processor; andat least one memory storing instructions which, when executed by the processor, cause the apparatus at least to perform the method of any one of claims 12-15.

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