Patent Publication Number: US-11659433-B2

Title: Modifying video call QoS based on a signal quality measurement

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of U.S. patent application Ser. No. 16/679,937, filed Nov. 11, 2019, which is a continuation of U.S. patent application Ser. No. 15/722,701, filed Oct. 2, 2017, (now U.S. Pat. No. 10,477,617, issued Nov. 12, 2019), which claims the benefit of U.S. Provisional Application No. 62/403,093, filed Oct. 1, 2016, all of which are hereby incorporated by reference in their entirety. 
    
    
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
     Examples of several of the various embodiments of the present invention are described herein with reference to the drawings. 
       FIG.  1    illustrates a block diagram of an example system  100  according to various embodiments. 
       FIG.  2    is a system diagram of an example communications system in which one or more disclosed embodiments may be implemented. 
       FIG.  3    is a system diagram of an example wireless transmit/receive unit (WTRU) as per an aspect of an embodiment. 
       FIG.  4    is a system diagram of an example radio access network and core network as per an aspect of an embodiment. 
       FIG.  5    is a block diagram of a base station and a wireless device as per an aspect of an embodiment. 
       FIG.  6    is an example ProSe Discovery message as per an aspect of an embodiment. 
       FIG.  7    is a flow diagram of an example procedure for Model A discovery as per an aspect of an embodiment. 
       FIG.  8    is a flow diagram showing an example procedure for the announcing MCS UE as per an aspect of an embodiment. 
       FIG.  9    is a flow diagram showing an example procedure for the monitoring MCS UE as per an aspect of an embodiment. 
       FIG.  10    is a flow diagram showing an example match reporting procedure as per an aspect of an embodiment. 
       FIG.  11    is a flow diagram showing an example proceduresfor Model B discovery as per an aspect of an embodiment. 
       FIG.  12    is a flow diagram showing an example procedure for the discoveree MCS UE as per an aspect of an embodiment. 
       FIG.  13    is a flow diagram of an example procedure for discoverer MCS UE as per an aspect of an embodiment. 
       FIG.  14    is a flow diagram showing an example matched reporting procedure as per an aspect of an embodiment. 
       FIG.  15    is a block diagram of an example MCS UE-to-network relay as per an aspect of an embodiment. 
       FIG.  16    is a flow diagram showing an example IMS registration procedure of an MCS UE as per an aspect of an embodiment. 
       FIG.  17    is a flow diagram of an example IMS registration of an MCS UE as per an aspect of an embodiment. 
       FIG.  18    is a flow diagram shows an example MCS group session setup by MCS UE as per an aspect of an embodiment. 
       FIG.  19    is a flow diagram of an example MCS session setup by MCS UE A as per an aspect of an embodiment. 
       FIG.  20    is an example block diagram of an architecture configured to support an on-network Mission critical push to talk (MCPTT) service(s) as per an aspect of an embodiment. 
       FIG.  21    is an example block diagram of an architecture configured to support MCVideo as per an aspect of an embodiment. 
       FIG.  22    is an example block diagram of an architecture configured to support on-network MCVideo service(s) as per an aspect of an embodiment. 
       FIG.  23    is an example flow diagram of a mission critical session setup as per an aspect of an embodiment. 
       FIG.  24    is an example flow diagram of an Internet protocol connectivity access network (IP CAN) session setup as per an aspect of an embodiment. 
       FIG.  25    is a block diagram illustrating an example MC UE engaged in a mission critical session with MC UE 2  as per an aspect of an embodiment. 
       FIG.  26 A  is an example table of a list of ICSIs and/or IARIs as per an aspect of an embodiment of the present disclosure. 
       FIG.  26 B  is an example table of a list of ICSIs and/or IARIs as per an aspect of an embodiment of the present disclosure. 
       FIG.  27    is a flow diagram of an example modified mission critical media session as per an aspect of an embodiment. 
       FIG.  28    is a flow diagram of an example network initiated IP CAN session modification as per an aspect of an embodiment. 
       FIG.  29    is a flow diagram of an example MC UE  1  initiated IP CAN session modification as per an aspect of an embodiment. 
       FIG.  30    is an example flow diagram as per an aspect of an embodiment of the present disclosure. 
       FIG.  31    is an example flow diagram as per an aspect of an embodiment of the present disclosure. 
       FIG.  32    is an example flow diagram as per an aspect of an embodiment of the present disclosure. 
       FIG.  33    is an example flow diagram as per an aspect of an embodiment of the present disclosure. 
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS 
     Example embodiments are generally directed to critical communication service (e.g., A) that may involve use of wireless mobile telecommunication cellular and/or wireless mobile broadband technologies. Wireless mobile broadband technologies may include wireless technologies suitable for use with wireless devices and/or user equipment (UE), such as one or more third generation (3G), fourth generation (4G) or emerging fifth generation (5G) wireless standards, revisions, progeny and variants. Examples of wireless mobile broadband technologies may include without limitation any of the Institute of Electrical and Electronics Engineers (IEEE) 802.16m and 802.16p standards, 3rd Generation Partnership Project (3GPP) Long Term Evolution (LTE) and LTE-Advanced (LTE-A) standards, and International Mobile Telecommunications Advanced (IMT-ADV) standards, including their revisions, progeny, and variants. Other suitable examples may include, without limitation, Global System for Mobile Communications (GSM)/Enhanced Data Rates for GSM Evolution (EDGE) technologies, Universal Mobile Telecommunications System (UMTS)/High Speed Packet Access (HSPA) technologies, Worldwide Interoperability for Microwave Access (WiMAX) or the WiMAX II technologies, Code Division Multiple Access (CDMA) 2000 system technologies (e.g., CDMA2000 I×RTT, CDMA2000 EV-DO, CDMA EV-DV, and so forth), High Performance Radio Metropolitan Area Network (HIPERMAN) technologies as defined by the European Telecommunications Standards Institute (ETSI) Broadband Radio Access Networks (BRAN), Wireless Broadband (WiBro) technologies, GSM with General Packet Radio Service (GPRS) system (GSM/GPRS) technologies, High Speed Downlink Packet Access (HSDPA) technologies, High Speed Orthogonal Frequency-Division Multiplexing (OFDM) Packet Access (HSOPA) technologies, High-Speed Uplink Packet Access (HSUPA) system technologies, 3 GPP Rel. 8, 9, 10 or 11 of LTE/System Architecture Evolution (SAE), and so forth. The examples are not limited in this context. In this disclosure, the term “critical” is being employed as a term of art as disclosed, for example, in various communication specifications and is therefore not intended to otherwise limit the scope of the claims. 
     By way of example and not limitation, various examples may be described with specific reference to various 3 GPP radio access network (RAN) standards, such as the 3 GPP Universal Terrestrial Radio Access Network (UTRAN), the 3 GPP Evolved Universal Terrestrial Radio Access Network (E-UTRAN) and 3GPP&#39;s suite of UMTS and LTE/LTE-Advanced Technical Specifications (in case of LTE/LTE-Advanced collectively “3GPP LTE Specifications” according to the 36 Series of Technical Specifications), and IEEE 802.16 standards, such as, for example, the IEEE 802.16-2009 standard and current third revision to IEEE 802.16 referred to as “802.16 Rev3” consolidating standards 802.16-2009, 802.16h-2010 and 802.16m-2011, and the IEEE 802.16p draft standards including IEEE P802.16.1b/D2 Jan. 2012 titled “Draft Amendment to IEEE Standard for WirelessMAN-Advanced Air Interface for Broadband Wireless Access Systems, Enhancements to Support Machine-to-Machine Applications” (collectively “IEEE 802.16 Standards”), and any drafts, revisions or variants of the 3 GPP LTE Specifications and the IEEE 802.16 Standards. Although some embodiments may be described as a 3GPP LTE Specifications or IEEE 802.16 Standards system by way of example and not limitation, it may be appreciated that other types of communications system may be implemented as various other types of mobile broadband communications systems and standards. The examples are not limited in this context. 
     As contemplated in the present disclosure, mission critical service (MCS) may support an enhanced mission critical push-to-talk (MCPTT) service, an enhanced mission critical video (MCVIDEO) service, an enhanced mission critical data/message (MCDATA) service, and/or the like. An MCS service may be suitable for mission critical scenarios and may be based upon 3GPP EPS services. MCS may typically be a session initiation protocol (SIP) based service that may be provided via a centralized MCS server residing in a network (e.g., a 3GPP EPS network). The MCS server may be an IP Multimedia Subsystem (IMS) application server, but the MCS server may also be a non-IMS based SIP server. User equipment (UEs) may directly attach to the network to receive critical communication services from an MCS server. Some UEs may also utilize Proximity Services (ProSe) capabilities to indirectly attach to the network through a relay UE. UEs utilizing ProSe capabilities may be outside of a coverage area of the network and may be referred to as remote UEs. 
       FIG.  1    illustrates a block diagram of an example system  100  according to various embodiments. According to an embodiment, elements of system  100  may be arranged for providing critical communication services to one or more UEs (e.g. UE  130 , UE  140  and UE  150 ). These critical communication services may comprise MCS services as specified in, for example, 3GPP technical specification (TS) 22.179, entitled “Technical Specification Group Services and System Aspects; MCS over LTE, Stage 1”, Release 13, V13.0.1, published in January of 2015, and/or previous or subsequent releases or versions (hereinafter referred to as 3GPP TS 22.179). For example, as shown in  FIG.  1   , a network  101  may include an MCS server  120  that may serve as centralized server to enable network  101  to provide a SIP-based critical communication service to UEs  130 ,  140  or  150 . MCS server  120  may be arranged as, for example, an IMS application server or a non-IMS based SIP server. 
     According to an embodiment, access/core  190  may comprise elements of network  101  typically associated with 3GPP E-UTRAN access and 3GPP E-UTRAN core elements. For example, a UE such as UE  130  may gain access to network  101  via Uu  117  coupled to evolved Node B (eNB)  102 . Also, as shown in  FIG.  1   , MCS server  120  may couple to various access/core  190  elements. For example, MCS server  120  may couple to a policy and charging rules function (PCRF)  111  via  111 . Link  111  may represent an Rx interface reference point. MCS server  120  may also couple to a serving gateway/packet data gateway (SGW/PWG)  112  via SGi  113 . SGi  113  may represent an SGi interface reference point. (According to various embodiments, an interface may comprise and/or be a reference point). MCS server  120  may also couple to a broadcast/multicast-service center (BM-SC)  114  via MB 2   115 . MB 2   115  may represent an MB 2  reference point. 
     Mobile management entity (MME)  104  and multimedia broadcast/multicast service gateway (MBMS GW)  106  may provide core 3 GPP E-UTRAN services to MCS server  120  and/or UEs  130 ,  140  and  150  to facilitate network  101  in providing critical communication services. 
     According to an embodiment, UE  130  may attach directly to MCS server  120 . UE  130  may comprise an MCS client that may be arranged as a SIP-based MCS client for communication with MCS server  120 . MCS server  120  may be arranged as a type of group communication service application server (GCS AS) and GC 1   173  may represent a GC 1  reference point through which MCS server  120  couples with MCS client at UE  130 . 
     According to an embodiment, UEs out of network coverage of network  101  may still be able to obtain critical communication service by coupling through UEs serving as UE-to-network relays such as UE  130 . For example, UE  150  may be able to indirectly couple to MCS server  120  via a first link  151  between UE  150  and UE  130  and through a second link (GCl  173 ) between UE  130  and MCS server  120 . 
     According to an embodiment, UE  130  acting as an UE-to-network relay may relay traffic from MCS server  120  for authorized UEs and/or authorized groups of UEs (e.g., belonging to an MCS group). UE  130  may act as an UE-to-network relay for groups of which it is not a member. As such, a relay UE, such as UE  130 , may comprise logic and/or features to enable the relay UE to act as a node between an MCS server and a remote UE such as UE  150  via link  151 . 
     According to an embodiment, critical communication content may be delivered to directly coupled UEs such as UEs  130  or  140  in either a unicast mode (e.g., via EPS bearers) and/or in multicast mode (e.g., via evolved MBMS (eMBMS) bearers). Use of eMBMS bearers may be justified in cases where a sufficient number of UEs are physically located within a same coverage area or cell. When the number of UEs in a cell is low, unicast delivery via EPS may be more efficient compared to eMBMS or multicast delivery. MCS server  120  may comprise logic and/or features capable of monitoring the number of UEs in a cell and then adjust a delivery mode accordingly. 
     According to an embodiment, as part of ProSe capabilities, UE  130  and UE  150  may establish a direct link  151 . UE  130  may couple to MCS server  120  through GC 1   173 . Alternatively, UE  150  may couple to MCS server  120  via: (1) link  151  between UE  150  and UE  130 ; (2) link  131  between UE  130  and UE  140 ; and (3) GCI  174  between UE  140  to MCS Server  120 . Establishment of the direct link may comprise relay discovery, mutual authentication and IP address assignment. Establishment of the direct link may comprise UE  130  and UE  150  setting up a wireless local area network (WLAN) direct connection. The WLAN direct connection may be arranged to operate according to Ethernet wireless standards (including progenies and variants) associated with the IEEE Standard for Information technology-Telecommunications and information exchange between systems—Local and metropolitan area networks—Specific requirements Part 1 1: WLAN Media Access Controller (MAC) and Physical Layer (PHY) Specifications, published March 2012, and/or later versions of this standard (“IEEE 802.11”). According to an embodiment, following the same logic as mentioned above for MCS server  120  selecting a unicast or multicast delivery mode, logic and/or features of a relay UE such as UE  130  and/or  140  may choose a unicast or multicast delivery mode to relay information (e.g., critical communication content) to one or more remote UEs such as UE  150  and/or each other. 
     A direct link between UEs  140  and  130  may be established via, for example, a PC5 interface (e.g.  131 ). The PC5 interface may be selectively chosen to communicate information. It may be possible to use unicast delivery via the LTE-Uu interface. 
     Concepts expressed herein may be implemented in connection with cellular telephones and/or other types of User Equipment (UE) used on communication networks, and particularly wireless communication networks. Described below are one or more example communication networks and related equipment within which at least some of the aspects of the herein described concepts may be implemented. 
       FIG.  2    is a diagram of an example communications system  200  in which one or more disclosed embodiments may be implemented. The communications system  200  may comprise a multiple access system configured to provide content, such as voice, data, video, messaging, broadcast, etc., to multiple wireless users. The communications system  200  may enable multiple wireless users to access such content through the sharing of system resources, including, for example, wireless bandwidth. For example, communications systems  200  may employ one or more channel access processes, such as code division multiple access (CDMA), time division multiple access (TDMA), frequency division multiple access (FDMA), orthogonal FDMA (OFDMA), single-carrier FDMA (SC-FDMA), and/or the like. 
     As shown in  FIG.  2   , the communications system  200  may comprise wireless transmit/receive units (WTRUs)  202 A,  202 B,  202 C,  202 D, a radio access network (RAN)  204 , a core network  206 , the Internet  210 , and/or other networks  212 . It will be appreciated that the disclosed embodiments contemplate various numbers of WTRUs, base stations, networks, and/or network elements. Each of the WTRUs  202 A,  202 B,  202 C,  202 D may be configured to operate and/or communicate in a wireless environment. By way of example, WTRUs  202 A,  202 B,  202 C,  202 D may be configured to transmit and/or receive wireless signals and may comprise user equipment (UE), a mobile station, a fixed or mobile subscriber unit, a pager, a cellular telephone, a personal digital assistant (PDA), a smartphone, a laptop, a netbook, a personal computer, a wireless sensor, consumer electronics, combinations thereof, and/or the like. 
     The communications systems  200  may also comprise a base station  214 A and/or base station  214 B. Each of the base stations  214 A,  214 B may be a type of device configured to wirelessly interface with at least one of the WTRUs  202 A,  202 B,  202 C,  202 D to facilitate access to one or more communication networks, such as core network  206 , Internet  210  and/or networks  212 . By way of example, base stations  214 A and/or  214 B may comprise a base transceiver station (BTS), a Node-B, an eNode B, a Home Node B, a Home eNode B, a site controller, an access point (AP), a wireless router, combinations thereof, and/or the like. While base stations  214 A and  214 B are each depicted as a single element, it will be appreciated that base stations  214 A and  214 B may comprise various numbers of interconnected base stations and/or network elements. 
     As illustrated, base station  214 A may be a part of the RAN  204 , which may also comprise other base stations and/or network elements (not shown), such as, for example, a base station controller (BSC), a radio network controller (RNC), relay nodes, combinations thereof, and/or the like. Base station  214 A and/or the base station  214 B may be configured to transmit and/or receive wireless signals within a particular geographic region, which may be referred to as a cell (not shown). The cell may be further divided into cell sectors. For example, the cell associated with the base station  214 A may be divided into three sectors. Thus, according to an embodiment, base station  214 A may comprise three transceivers, i.e., one for each sector of the cell. According to an embodiment, base station  214 A may employ multiple-input multiple output (MIMO) technology and, therefore, may utilize multiple transceivers for each sector of the cell. 
     Base stations  214 A and/or  214 B may communicate with one or more of the WTRUs (e.g.  202 A,  202 B,  202 C, and  202 D) over an air interface (e.g.  216 A,  216 B, ( 216 C and/or  216 E), and  216 D, respectively), which may comprise a wireless communication link (e.g., radio frequency (RF), microwave, infrared (IR), ultraviolet (UV), visible light, etc.). An air interface (e.g.  216 A,  216 B,  216 C,  216 D,  216 E,  216 F and  216 G) may be established employing a suitable radio access technology (RAT). 
     More specifically, as noted above, communications system  200  may comprise a multiple access system and may employ one or more channel access schemes, such as CDMA, TDMA, FDMA, OFDMA, SC-FDMA, combinations thereof, and/or the like. For example, base station  214 A in the RAN  204  and WTRUs  202 A,  202 B, and  202 C may implement a radio technology such as Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access (UTRA), which may establish air interface (e.g.  202 A,  202 B, and  202 C) employing wideband CDMA (WCDMA). WCDMA may comprise communication protocols such as High-Speed Packet Access (HSPA) and/or Evolved HSPA (HSPA+). HSPA may comprise High-Speed Downlink Packet Access (HSDPA) and/or High-Speed Uplink Packet Access (HSUPA). 
     According to an embodiment, base station  214 A and WTRUs  202 A,  202 B,  202 C may implement a radio technology such as Evolved UMTS Terrestrial Radio Access (E-UTRA), which may establish air interface (e.g.  216 A,  216 B, and  216 C, respectively) employing Long Term Evolution (LTE) and/or LTE-Advanced (LTE-A). 
     According to an embodiment, base station  214 A and WTRUs  202 A,  202 B,  202 C may implement radio technologies such as IEEE 802.16 (i.e., Worldwide Interoperability for Microwave Access (WiMAX)), CDMA2000, CDMA2000 1×, CDMA2000 EV-DO, Interim Standard 2000 (IS-2000), Interim Standard 95 (IS-95), Interim Standard 856 (IS-856), Global System for Mobile communications (GSM), Enhanced Data rates for GSM Evolution (EDGE), GSM EDGE (GERAN), combinations thereof, and/or the like. 
     Base station  214 B in  FIG.  2    may comprise a wireless router, Home Node B, Home eNode B, or an access point, for example, and may utilize a RAT for facilitating wireless connectivity in a localized area, such as a place of business, a home, a vehicle, a campus, combinations thereof, and/or the like. According to an embodiment, base station  214 B and WTRUs  202 C,  202 D may implement a radio technology such as IEEE 802.11 to establish a wireless local area network (WLAN). According to an embodiment, base station  214 B and WTRUs  202 C and  202 D may implement a radio technology such as IEEE 802.15 to establish a wireless personal area network (WPAN). According to an embodiment, base station  214 B and WTRUs  202 C and  202 D may utilize a cellular-based RAT (e.g., WCDMA, CDMA2000, GSM, LTE, LTE-A, etc.) to establish a picocell or femtocell. As shown in  FIG.  2   , base station  214 B may have a direct connection to the Internet  210 . Thus, base station  214 B may not be required to access the Internet  210  via the core network  206 . 
     The RAN  204  may be in communication with the core network  206 , which may be a type of network configured to provide voice, data, applications, and/or voice over internet protocol (VoIP) services to one or more of the WTRUs  202 A,  202 B,  202 C, and  202 D. For example, core network  206  may provide call control, billing services, mobile location-based services, pre-paid calling, Internet connectivity, video distribution, etc., and/or perform high-level security functions, such as user authentication. Although not shown in  FIG.  2   , it anticipated that according to an embodiment, RAN  204  and/or core network  206  may be in direct or indirect communication with other RANs that employ the same RAT as the RAN  204  or a different RAT. For example, in addition to being connected to the RAN  204 , which may utilize an E-UTRA radio technology, the core network  206  may also be in communication with another RAN (not shown). 
     Core network  206  may serve as a gateway for the WTRUs  202 A,  202 B,  202 C and/or  202 D to access the PSTN  208 , the Internet  210  and/or other networks  212 . The Internet  210  may comprise a global system of interconnected computer networks and devices that use common communication protocols, such as the transmission control protocol (TCP), user datagram protocol (UDP) and the internet protocol (IP) in the TCP/IP internet protocol suite. Other networks  212  may comprise wired and/or wireless communications networks owned and/or operated by other service providers. For example, the networks  212  may comprise another core network connected to one or more RANs, which may employ the same RAT as the RAN  204  or a different RAT. 
     Some or all of the WTRUs  202 A,  202 B,  202 C, and  202 D in the communications system  200  may comprise multi-mode capabilities (i.e., the WTRUs  202 A,  202 B,  202 C, and  202 D may comprise multiple transceivers for communicating with different wireless networks over different wireless links). For example, example WTRU  300  shown in  FIG.  3    may be configured to communicate with base station  214 A, which may employ a cellular-based radio technology, and with the base station  214 B, which may employ an IEEE 802 radio technology. 
       FIG.  3    is a system diagram of an example WTRU  300 . As shown in  FIG.  3   , example WTRU  300  may comprise a processor  318 , a transceiver  320 , a transmit/receive element  322 , a speaker/microphone  324 , a keypad  326 , a display/touchpad  328 , non-removable memory  330 , removable memory  332 , a power source  334 , a global positioning system (GPS) chipset  336 , and other peripherals  338 . It will be appreciated that the WTRU  300  may comprise a sub-combination of the foregoing elements while remaining consistent with an embodiment. For example, an WRTU  300  embodiment may be implemented without one or more of the dashed elements  324 ,  328 ,  336  and/or  332 . 
     The processor  318  may be a general purpose processor, a special purpose processor, a conventional processor, a digital signal processor (DSP), a plurality of microprocessors, one or more microprocessors in association with a DSP core, a controller, a microcontroller, Application Specific Integrated Circuits (ASICs), Field Programmable Gate Array (FPGAs) circuits, any other type of integrated circuit (IC), a state machine, and the like. Processor  318  may perform signal coding, data processing, power control, input/output processing and/or other functionality that enables example WTRU  300  to operate in a wireless environment. Processor  318  may be coupled to the transceiver  320 , which may be coupled to the transmit/receive element  322 . While  FIG.  3    depicts elements such as, for example, processor  318  and transceiver  320  as separate components, it will be appreciated that the elements such as processor  318  and the transceiver  320  may be integrated together in an electronic package and/or chip. While  FIG.  3    depicts elements such as, for example, processor  318  and transceiver  320  as individual components, it will be appreciated that the elements such as processor  318  and the transceiver  320  may be implemented as a collection of other elements. 
     The transmit/receive element  322  may be configured to transmit signals to, or receive signals from, a base station (e.g., the base station  214 A) over the air interface  316 . For example, in an embodiment, the transmit/receive element  322  may be an antenna configured to transmit and/or receive RF signals. According to an embodiment, the transmit/receive element  322  may be an emitter/detector configured to transmit and/or receive IR, UV, or visible light signals, for example. According to an embodiment, the transmit/receive element  322  may be configured to transmit and receive both RF and light signals. It will be appreciated that the transmit/receive element  322  may be configured to transmit and/or receive any combination of wireless signals. 
     In addition, although the transmit/receive element  322  is depicted in  FIG.  3    as a single element, example WTRU  300  may comprise any number of transmit/receive elements  322 . More specifically, example WTRU  300  may employ MIMO technology. Thus, according to an embodiment, example WTRU  300  may comprise two or more transmit/receive elements  322  (e.g., multiple antennas) for transmitting and receiving wireless signals over the air interface  316 . 
     Transceiver  320  may be configured to modulate signals that are to be transmitted by transmit/receive element  322  and to demodulate signals received by transmit/receive element  322 . As noted above, example WTRU  300  may have multi-mode capabilities. Thus, the transceiver  320  may comprise multiple transceivers for enabling example WTRU  300  to communicate via multiple RATs, such as E-UTRA and IEEE 802.11, for example. 
     Processor  318  of example WTRU  300  may be coupled to, and may receive user input data from, for example, the speaker/microphone  324 , the keypad  326  and/or the display/touchpad  328  (e.g., a liquid crystal display (LCD) display unit or organic light-emitting diode (OLED) display unit). Processor  318  may output user data to, for example, the speaker/microphone  324 , the keypad  326  and/or the display/touchpad  328 . Processor  318  may access information from, and store data in, a type of suitable memory, such as the non-removable memory  330  and/or the removable memory  332 . The non-removable memory  330  may comprise random-access memory (RAM), read-only memory (ROM), a hard disk, and/or other type of memory storage device. The removable memory  332  may comprise a subscriber identity module (SIM) card, a memory stick, a secure digital (SD) memory card, and/or the like. According to an embodiment, processor  318  may access information from, and store data in, memory that is not physically located on example WTRU  300 , such as on a server or a home computer (not shown). 
     Processor  318  may receive power from the power source  334 , and may be configured to distribute and/or control the power to the other components in example WTRU  300 . Power source  334  may be a suitable device for powering example WTRU  300 . For example, power source  334  may comprise one or more dry cell batteries (e.g., nickel-cadmium (NiCd), nickel-zinc (NiZn), nickel metal hydride (NiMH), lithium-ion (Li-ion), etc.), solar cells, fuel cells, combinations thereof, and/or the like. 
     Processor  318  may also be coupled to GPS chipset  336 , which may be configured to provide location information (e.g., longitude and latitude) regarding the current location of example WTRU  300 . In addition to, and/or in lieu of, the information from the GPS chipset  336 , example WTRU  300  may receive location information over the air interface  316  from a base station (e.g., base stations  214 A,  214 B) and/or determine a location based on the timing of the signals being received from two or more nearby base stations. It will be appreciated that the WTRU  300  may acquire location information by way of other suitable location-determination process(es) while remaining consistent with an embodiment. 
     Processor  318  may further be coupled to other peripherals  338 , which may comprise one or more software and/or hardware modules that provide additional features, functionality, and/or wired or wireless connectivity. For example, peripherals  338  may comprise, for example, an accelerometer, an e-compass, a satellite transceiver, a digital camera (for photographs or video), a universal serial bus (USB) port, a vibration device, a television transceiver, a hands free headset, a Bluetooth™ module, a frequency modulated (FM) radio unit, a digital music player, a media player, a video game player module, an Internet browser, a combination thereof, and/or the like. 
       FIG.  4    is a system diagram of an example communications system comprising an example RAN  404  and an example core network  406 . This example communications system is disclosed for example purposes. Variations in communications systems may be implemented within the scope of the embodiment. In this example embodiment, RAN  404  may employ an E-UTRA radio technology to communicate with the WTRUs  402 A,  402 B and/or  402 C over air interfaces  416 A,  416   b  and/or  416 C respectively. RAN  404  may be in communication with the core network  406 . 
     Example RAN  404  may comprise eNBs  460 A,  460 B and/or  460 C, though it will be appreciated that the RAN  404  may comprise various numberd of eNBs while remaining consistent with an embodiment. The eNBs  460 A,  460 B and/or  460 C may each comprise one or more transceivers for communicating with the WTRUs  402 A,  402 B and/or  402 C over air interface  416 A,  416 B and/or  416 C respectively. In an embodiment, the eNBs  460 A,  460 B and/or  460 C may implement MIMO technology. Thus, the eNB  460 A, for example, may use multiple antennas to transmit wireless signals to, and receive wireless signals from, example WTRUs  402 A. 
     Some WTRUs may be configured to communicate with each other directly. For example, as illustrated, WTRU  402 E may be configured to communicate with example WTRU  402 B and/or example WTRU  402 C over the air interfaces  416 F and/or  416 E, respectively. Similarly, example WTRU  402 D may be configured to communicate with example WTRU  402 C over the air interfaces  416 D. 
     Each of the eNBs  460 A,  460 B, and/or  460 C may be associated with a particular cell (not shown) and may be configured to handle radio resource management decisions, handover decisions, scheduling of users in the uplink and/or downlink, and the like. As shown in  FIG.  4   , the eNBs  460 A,  460 B and/or  460 C may communicate with one another over, for example: an X2 interface, a reference point, and/or the like. 
     Example core network  406  shown in  FIG.  4    may comprise a mobility management gateway (MME)  462 , a serving gateway  464 , a packet data network (PDN) gateway  466 , and/or the like. While each of the foregoing elements are depicted as part of the core network  406 , it will be appreciated that various elements operating in a core network (e.g.  406 ) may be owned and/or operated by an entity other than the core network operator. 
     The MME  462  may be connected to each of the eNBs  460 A,  460 B,  460 C in RAN  404  via an S1 interface, a reference point, and/or the like and may serve as a control node. For example, the MME  462  may be responsible for authenticating users of the WTRUs  402 A,  402 B,  402 C,  402 D and/or  402 E, bearer activation/deactivation, selecting a particular serving gateway during an initial attach of the WTRUs  402 A,  402 B,  402 C,  402 D and/or  402 E, and/or the like. The MME  462  may also provide a control plane function for switching between the RAN  404  and other RANs (not shown) that employ other radio technologies, such as, for example, GSM and/or WCDMA. 
     Serving gateway  464  may be connected to each of the eNode Bs  460 A,  460 B and/or  460 C in the RAN  404  via an S1 interface, a reference point, and/or the like. The serving gateway  464  may generally route and forward user data packets to and from the WTRUs  402   a ,  402 B and/or  402 C. The serving gateway  464  may also perform other functions, such as anchoring user planes during inter-eNode B handovers, triggering paging when downlink data is available for the WTRUs  402 A,  402 B and/or  402 C, managing and storing contexts of the WTRUs  402 A,  402 B and/or  402 C, and/or the like. 
     The serving gateway  464  may also be connected to the PDN gateway  466 , which may provide the WTRUs  402   a ,  402 B and/or  402 C with access to packet-switched networks, such as the Internet  410 , to facilitate communications between the WTRUs  402 A,  402 B and/or  402 C and IP-enabled devices. 
     Example core network  406  may facilitate communications with other networks. For example, core network  406  may provide the WTRUs  402 A,  402 B and  402 C with access to circuit-switched networks to facilitate communications between the WTRUs  402 A,  402 B,  402 C and traditional land-line communications devices. For example, the core network  406  may comprise, and/or may communicate with, an IP gateway (e.g., an IP multimedia subsystem (IMS) server) that serves as an interface between the core network  406  and a PSTN. In addition, the core network  406  may provide the WTRUs  402 A,  402 B,  402 C with access to the networks  412 , which may comprise other wired or wireless networks that are owned and/or operated by other service providers. 
       FIG.  5    is an example block diagram of a base station  501  and a wireless device  506 , as per an aspect of an embodiment of the present invention. A communication network  500  may comprise at least one base station  501  and at least one wireless device  506 . The base station  501  may comprise at least one communication interface  502 , at least one processor  503 , and at least one set of program code instructions  505  stored in non-transitory memory  504  and executable by the at least one processor  503 . The wireless device  506  may comprise at least one communication interface  507 , at least one processor  508 , and at least one set of program code instructions  510  stored in non-transitory memory  509  and executable by the at least one processor  508 . Communication interface  502  in base station  501  may be configured to engage in communication with communication interface  507  in wireless device  506  via a communication path that comprises at least one wireless link  511 . Wireless link  511  may be a bi-directional link. Communication interface  507  in wireless device  506  may also be configured to engage in a communication with communication interface  502  in base station  501 . Base station  501  and wireless device  506  may be configured to send and receive data over wireless link  511  using multiple frequency carriers. According to some of the various aspects of embodiments, transceiver(s) may be employed. A transceiver is a device that comprises both a transmitter and receiver. Transceivers may be employed in devices such as wireless devices, base stations, relay nodes, and/or the like. 
     An interface may be a hardware interface, a firmware interface, a software interface, and/or a combination thereof. The hardware interface may comprise connectors, wires, electronic devices such as drivers, amplifiers, and/or the like. A software interface may comprise code stored in a memory device to implement protocol(s), protocol layers, communication drivers, device drivers, combinations thereof, and/or the like. A firmware interface may comprise a combination of embedded hardware and code stored in and/or in communication with a memory device to implement connections, electronic device operations, protocol(s), protocol layers, communication drivers, device drivers, hardware operations, combinations thereof, and/or the like. 
     The term configured may relate to the capacity of a device whether the device is in an operational or non-operational state. Configured may also refer to specific settings in a device that effect the operational characteristics of the device whether the device is in an operational or non-operational state. In other words, the hardware, software, firmware, registers, memory values, and/or the like may be “configured” within a device, whether the device is in an operational or nonoperational state, to provide the device with specific characteristics. Terms such as “a control message to cause in a device” may mean that a control message has parameters that may be used to configure specific characteristics in the device, whether the device is in an operational or non-operational state. 
     According to some of the various aspects of embodiments, an LTE network may comprise a multitude of base stations, providing a user plane PDCP/RLC/MAC/PHY and control plane (RRC) protocol terminations towards the wireless device. The base station(s) may be interconnected with other base station(s) (e.g. employing an X2 interface, reference point, and/or the like). The base stations may also be connected employing, for example, an S1 interface to an EPC. For example, the base stations may be interconnected to the MME employing the S1-MME interface, reference point, and/or the like and to the Serving Gateway (S-G) employing the S1-U reference point. The S1 interface, reference point, and/or the like may support a many-to-many relation between MMEs/Serving Gateways and base stations. A base station may comprise many sectors for example: 1, 2, 3, 4, or 6 sectors. A base station may comprise many cells, for example, ranging from 1 to 50 cells or more. A cell may be categorized, for example, as a primary cell or secondary cell. At RRC connection establishment/re-establishment/handover, one serving cell may provide the NAS (non-access stratum) mobility information (e.g. TAI), and at RRC connection re-establishment/handover, one serving cell may provide the security input. This cell may be referred to as the Primary Cell (PCell). In the downlink, the carrier corresponding to the PCell may be the Downlink Primary Component Carrier (DL PCC), while in the uplink, it may be the Uplink Primary Component Carrier (UL PCC). Depending on wireless device capabilities, Secondary Cells (SCells) may be configured to form together with the PCell a set of serving cells. In the downlink, the carrier corresponding to an SCell may be a Downlink Secondary Component Carrier (DL SCC), while in the uplink, it may be an Uplink Secondary Component Carrier (UL SCC). An SCell may or may not have an uplink carrier. 
     A cell, comprising a downlink carrier and optionally an uplink carrier, may be assigned a physical cell ID and a cell index. A carrier (downlink or uplink) may belong to only one cell. The cell ID or Cell index may also identify the downlink carrier or uplink carrier of the cell (depending on the context it is used). In the specification, cell ID may be equally referred to a carrier ID, and cell index may be referred to carrier index. In implementation, the physical cell ID or cell index may be assigned to a cell. A cell ID may be determined using a synchronization signal transmitted on a downlink carrier. A cell index may be determined using RRC messages. For example, when the specification refers to a first physical cell ID for a first downlink carrier, the specification may mean the first physical cell ID is for a cell comprising the first downlink carrier. The same concept may apply to, for example, carrier activation. When the specification indicates that a first carrier is activated, the specification may equally mean that the cell comprising the first carrier is activated. 
     Embodiments may be configured to operate as needed. The disclosed mechanism may be performed when certain criteria are met, for example, in a wireless device, a base station, a radio environment, a network, a combination of the above, and/or the like. Example criteria may be based, at least in part, on for example, traffic load, initial system set up, packet sizes, traffic characteristics, a combination of the above, and/or the like. When the one or more criteria are met, various example embodiments may be applied. Therefore, it may be possible to implement example embodiments that selectively implement disclosed protocols. 
     A base station may communicate with a mix of wireless devices. Wireless devices may support multiple technologies, and/or multiple releases of the same technology. Wireless devices may have some specific capability(ies) depending on its wireless device category and/or capability(ies). A base station may comprise multiple sectors. When this disclosure refers to a base station communicating with a plurality of wireless devices, this disclosure may refer to a subset of the total wireless devices in a coverage area. This disclosure may refer to, for example, a plurality of wireless devices of a given LTE release with a given capability and in a given sector of the base station. The plurality of wireless devices in this disclosure may refer to a selected plurality of wireless devices, and/or a subset of total wireless devices in a coverage area which perform according to disclosed methods, and/or the like. There may be a plurality of wireless devices in a coverage area that may not comply with the disclosed methods, for example, because those wireless devices perform based on older releases of LTE technology. 
     In order to set up a session for a mission critical service (MCS), where the mission critical service may be mission critical push-to-talk (MCPTT), the MCS UEs affiliated to MCS groups may first discover each other. This discovery may be a restricted discovery since MCS is a public safety feature. In the restricted discovery, the discoverer UEs and discoveree UEs may be authorized by being pre-provisioned with one or more parameters for the discovery procedure. 
     Examples for ProSe direct discovery methods are Model A and Model B. 
     Model A may include the following examples two roles for the ProSe-enabled UEs that are participating in ProSe Direct Discovery: Announcing UE: a) The UE announces certain information that may be used by UEs in proximity that have permission to discover. b) Monitoring UE: The UE that monitors certain information of interest in proximity of announcing UEs. 
     In Model A the announcing UE may broadcast discovery messages at discovery intervals (e.g. pre-defined intervals) and the monitoring UEs that are interested in these messages may read them and may process them. In an example, this model may be equivalent to “I am here” since the announcing UE may broadcast information about itself e.g. its restricted ProSe application code in the discovery message. 
     The UE may act as “announcing UE” in the carrier frequency signaled by the serving PLMN when using Model A mode. The UE may act as a “monitoring” UE in the resources of the serving PLMN and Local PLMNs, when using Model A mode. When inter-PLMN discovery transmission is supported, the carrier frequency may be operated by a PLMN other than the serving PLMN. Open and/or restricted discovery types may be supported by Model A. 
     Model B, when restricted discovery type is used, includes the following examples two roles for the ProSe-enabled UEs that are participating in ProSe Direct Discovery: a) Discoverer UE: The UE transmits a request containing certain information about what it is interested to discover. b) Discoveree UE: The UE that receives the request message may respond with some information related to the discoverer&#39;s request. 
     In an example, it is equivalent to “who is there/are you there”. The discoverer UE sends information about other UEs that may like to receive responses from, e.g. the information may be about a ProSe application identity corresponding to a group and the members of the group may respond. 
     When using Model B discovery, the discoverer UE and discoveree UE may announce in the carrier frequency signaled by the serving PLMN. When inter-PLMN discovery transmission is supported, the carrier frequency may be operated by a PLMN other than the serving PLMN. The discoverer UE and discoveree UE may be allowed to monitor in the serving PLMN and Local PLMNs when authorized. In an example implementation, only restricted discovery type may support by Model B. In an example application, the public safety discovery may be considered restricted. The monitoring UE/discoverer UE may need to have authorization (such as through pre-provisioned parameters) to perform discovery of the appropriate service(s). 
     The public safety discovery is considered restricted and depending on Model A or Model B, it may use ProSe restricted code for Model A, it may use ProSe query code/ProSe response code respectively for Model B. 
     These code parameters may be n bits, e.g. 64 bits, and may be part of ProSe Application Code. They may correspond to one or more restricted ProSe application user ID(s) (RPAUID). The ProSe application user ID may be allocated and bound to ProSe discovery UE ID (PDUID) by the ProSe application server. 
       FIG.  6    is an example of a ProSe Discovery message which may be employed for discovery procedures in Model A and Model B. In Model A, the announcing MCS UE may use ProSe restricted code and if the application-controlled extension is used, it may use ProSe restricted code prefix and ProSe restricted code suffix(es) to announce its identity over the PC5 interface. The monitoring MCS UE may use discovery filter which may be provided by the HPLMN ProSe function comprising the ProSe restricted code (or ProSe restricted code prefix with ProSe Restricted Code suffix pool if restricted direct discovery with application-controlled extension was requested by the announcing MCS UE) to monitor the announcing MCS UE for a duration of time. 
     Model A may compromise a procedure for the announcing MCS UE and a procedure for the monitoring MCS UE. It may include a matching procedure for the case when the monitoring MCS UE receives ProSe restricted code over the air that matches the discovery filter provided by the HPLMN ProSe function to the monitoring MCS UE in the discovery response message, however the corresponding restricted ProSe application UE identity (RPAUID) does not have valid validity timer. 
       FIG.  7    is a flow diagram of an example procedure for Model A discovery. This example procedure for the Model A discovery may include one or more of the following: 
     Authorization: The MCS UE may get authorized for restricted ProSe direct discovery. In an example, MCS may be public safety and the ProSe direct discovery may be restricted. 
     Announcement: The announcing MCS UE may request for discovery and may receive the ProSe restricted code (or ProSe restricted code prefix and ProSe restricted code suffix(es) to announce itself, if the application-controlled extension is used). The announcing MCS UE may announce the ProSe restricted code (or ProSe restricted code prefix and ProSe restricted code suffix(es) to announce itself, if the application-controlled extension is used). 
     Monitoring: The monitoring MCS UE may request for discovery and may receive the ProSe Filter comprising the ProSe Restricted Code (or ProSe Restricted Code Prefix and ProSe Restricted Code Suffix(es) to announce itself, if the application-controlled extension is used). The monitoring MCS UE may monitor for the ProSe restricted code (or ProSe restricted code prefix and ProSe restricted code suffix(es) to announce itself, if the application-controlled extension is used). 
     Match-Reporting: The monitoring UE may match-report if having monitored ProSe restricted code (or ProSe restricted code prefix and ProSe restricted code suffix(es) to announce itself, if the application-controlled extension is used) with corresponding PRAUID with no valid validity timer. 
     The announcing, monitoring, and match-reporting procedures are explained below.  FIG.  8   ,  FIG.  9   , and  FIG.  10   . 
       FIG.  8    is a flow diagram showing an example procedures for the announcing MCS UE. An example procedure for the announcing MCS UE is as follows: 
     The application client in the MCS UE may retrieve the ProSe discovery UE identity (PDUID) and may provide it to the ProSe application server. The ProSe application server may allocate a restricted ProSe application UE identity (RPAUID) for that PDUID, may store the binding between the PDUID and the RPAUID and may return the RPAUID to the application client in the MCS UE. MCS UE may use RPAUID instead of PDUID since MCS is a public safety feature. 
     MCS UE may construct a discovery request message containing RPAUID, UE identity set to international mobile subscriber identity (IMSI), command=announce, discovery type set to restricted discovery, application ID set to unique identifier of the MCS application ID, discovery entry ID indicating if this is a new request, optional requested discovery timer set to validity timer associated with the expected ProSe restricted code from the HPLMN ProSe Function (if it is set to zero, the MCS UE is requesting to remove the discovery entity ID and release the associated resources), (if application-controlled extension is used) application level container containing the request and the relevant information, announcing type such as “on demand” for the indicated application, and the PLMN ID of the carrier frequency in announcing PLMN ID if the serving PLMN signaled carrier frequency is not operated by HPLMN or VPLMN and if inter-PLMN ProSe discovery transmission is supported. MCS UE may send the discovery request message to HPLMN ProSe function. 
     HPLMN ProSe function may check for authorization for the MCS application. If there is not any associated MCS UE context, the HPLMN ProSe function may check with HSS and if needed may create a new context for the MCS UE that contains the subscription parameters for this MCS UE. HSS may provide MSISDN of the MCS UE and PLMN ID of where the MCS UE is registered. 
     The HPLMN ProSe function may send an authorization request containing RPAUID and request type set to “restricted discovery/announce” towards the ProSe application server. The authorization request may contain allowed number of suffixes if restricted Direct Discovery with application-controlled extension is used. The request type is set to “restricted discovery with application-controlled extension/announce”. 
     The ProSe application server may answer by an authorization response containing PDUID(s) corresponding the RPAUID stored in the ProSe application server and response type set to “restricted discover/announce ack.” The authorization respond may include ProSe restricted code suffix pool with allocated suffixes by the ProSe Application if restricted direct discovery with application-controlled extension is used. The response type is set to “restricted discovery with application-controlled extension/announce ack”. 
     HPLMN ProSe function may assign a ProSe restricted code corresponding to the RPAUID in the discovery request and an associated validity timer which identifies the duration of validity of the ProSe restricted code. MCS UE may use this ProSe restricted code within this validity duration if PLMN is not changed. If restricted direct discovery with application-controlled is used, then HPLMN ProSe functions may assign ProSe restricted code prefix instead of ProSe restricted code. If discovery request message indicates “on demand” announcing and the “on demand” announcing is authorized and enabled based on application ID and operator&#39;s policy, the HPLMN ProSe function may store RPAUID, PreSe restriced code (or ProSe restricted code prefix) with the associated validity timer, and enabled indicator in the user context. “On demand” announcing is only activated based on an ongoing monitoring request, otherwise, the following steps are not executed. 
     If the Discovery request is authorized, HPLMN ProSe Function may construct announce authorization message containing RPAUID, MCS application ID, ProSe restricted code (or ProSe restricted code prefix with ProSe restricted code suffix pool if retsricted direct discovery with application-controlled extension is used) set to assigned code for this request, UE ID set to IMSI or mobile station identifier number (MSISDN), discovery entry ID, and validity timer. The HPLMN ProSe function may update the existing announcing MCS UE&#39;s discovery entry with the new ProSe restricted code (or the ProSe restricted code prefix with ProSe restricted code suffix pool if retsricted direct discovery with application-controlled extension is used) and the new validity timer by using the MCS UE&#39;s corresponding discovery entry ID included in the discovery request message. If discovery request message included discovery timer set to zero for a discovery entity ID, then the HPLMN ProSe function may inform the VPLMN ProSe function to remove resources for that discovery entry ID by setting the timer to zero. The HPLMN ProSe function may send the announce authorization message towards the VPLMN ProSe Function. 
     The VPLMN ProSe function may acknowledge the HPLMN ProSe function that it authorizes the MCS UE to perform restricted discovery announcing if the announce authorization message contain a new discovery entery ID. If the discovery entery ID already exists, the VPLMN ProSe function may acknowledge the update as requested. 
     If the announcing is not “on-demand”, the HPLMN ProSe function may construct a discovery respond message with ProSe restricted code (or ProSe restricted code prefix with ProSe restricted code suffix pool if restricted direct discovery with application-controlled extension is used), validity timer, and discovery entity ID. If the announcing is “on-demand” and is authorized and enabled, the HPLMN ProSe function may construct the discovery respond message with validity timer, announcing enabled indicator, and discovery entity ID. The validity timer is set to zero if it is zero in discovery request message originated by the MCS UE. The HPLMN ProSe function may send the discovery respond message towards the MCS UE. 
     MCS UE may start announcing the provided ProSe restricted code. if restricted direct discovery with application-controlled extension is used, the MCS UE may append a ProSe restricted code suffix from the received ProSe restricted code suffix pool to the ProSe Restricted Code Prefix to form a ProSe Restricted Code. The MCS UE may use different suffixes from the provided ProSe restricted code suffix pool to form and announce different ProSe restricted codes without having to contact the HPLMN ProSe function as long as the validity timer permits. If “on-demand” announcing is used and the HPLMN ProSe function has not provided ProSe restricted code (or ProSe restricted code prefix with ProSe restricted code suffix pool if restricted direct discovery with application-controlled extension is used), the MCS UE may wait for an announcing alert request message from the HPLMN ProSe function before announcing on PC5 interface. 
       FIG.  9    is a flow diagram showing an example procedures for the monitoring MCS UE. The example procedure for monitoring MCS UE is as follows: 
     The application client in the MCS UE may retrieve the ProSe discovery UE identity (PDUID) and may provide it to the ProSe application server. The ProSe application server may allocate a restricted ProSe application UE identity (RPAUID) for that PDUID, may store the binding between the PDUID and the RPAUID and may return the RPAUID to the application client in the MCS UE. The MCS UE may obtain RPAUIDs of those MCS target users from the ProSe Application Server passed in an application level container. RPAUID instead of PDUID is used since MCS is a public safety feature. 
     In order to get the discovery filter, the monitoring MCS UE may construct a discovery request message comprising RPAUID set to the monitoring MCS UE identity, UE identity set to IMSI, command=monitor, discovery type, application ID set to unique identifier for the application that triggered discovery procedure, application level container compromising the Target RPAUIDs that the MCS UE is to monitor, discovery entry ID showing the discovery identity that it is a new discovery or an existing one, and the optional requested discovery timer. The requested discovery timer may be set to zero to indicate HPLMN to delete the discovery filter(s) for that discovery entry ID. The application level container may include some information about ProSe restricted code suffix such as group or user specific information if direct discovery with application-controlled extension is used. The MCS UE may send the discovery request message towards HPLMN ProSe function. 
     HPLMN ProSe function may check for authorization for the MCS application. If there is not any associated MCS UE context, the HPLMN ProSe function may check with HSS and may create a new context for the MCS UE that contains the subscription parameters for this MCS UE. HSS provides also MSISDN of the MCS UE and PLMN ID of where the MCS UE is registered. 
     The HPLMN ProSe function may send an authorization request containing RPAUID and request type set to “restricted discovery/monitor” towards the ProSe application server. If restricted direct discovery with application-controlled extension is used, the request type is then set to “restricted discovery with application-controlled extension/monitor”. 
     The ProSe application server constructs an authorization response comprising target PDUIDs and corresponding Target RPAUID that the RPAUID in the authorization request may monitor, PDUID of the requesting MCS UE, and response type set to “restricted discovery/monitor ack” (or to “restricted discovery with application-controlled extension/monitor ack” if restricted direct discovery with application-controlled extension is used). The ProSe application server may send the authorization response towards the HPLMN ProSe function. 
     The HPLMN ProSe function may construct a monitor request message comprising RPAUID of monitoring MCS UE, UE identity set to IMSI or MSISDN, Target PDUID and corresponding target RPAUID, application ID set to unique identifier for application that triggered the discovery procedure, and discovery entry ID to identify the discovery entry being new or an existing one. The HPLMN ProSe function may send the monitor request towards the target PLMN ProSe function which belongs to the monitoring MCS UE. If the discovery entry ID is an existing one, the target PLMN ProSe function may modify the existing discovery procedure with the parameters included in the monitor request message. 
     The target PLMN ProSe function may retrieve the ProSe restricted code (or the ProSe restricted code prefix if the restricted direct discovery with application-controlled extension is used) corresponding to the targeted PDUID, targeted RPAUID, and application ID. If in the context of the announcing MCS UE, the announcing enabled indicator is stored, the target PLMN ProSe function may construct an announcing alert request message comprising RPAUID indicating which monitoring MCS UE is interested in the targeted MCS UE announcement, application ID set to unique identifier for the application that triggered discovery procedure, ProSe restricted code which was retrieved from the context of the targeted announcing MCS UE (or ProSe restricted code prefix with ProSe restricted code suffix pool if restricted direct discovery with application-controlled extension was requested by the announcing MCS UE), and discovery entry ID to indicate it is a new discovery entity or an existing one. The target PLMN PRoSe function may send the message towards the targeted MCS UE and upon receipt of the announce alert response message from that MCS announcing UE, the ProSe function removes the announcing enabled indication associated to the ProSe restricted code (or ProSe restricted code prefix with ProSe restricted code suffix pool if restricted direct discovery with application-controlled extension was requested by the announcing MCS UE) from the Announcing MCS UE context. The MCS UE may now start announcing the ProSe restricted code (or ProSe restricted code prefix with ProSe restricted code suffix pool if restricted direct discovery with application-controlled extension was requested by the announcing MCS UE). 
     The target ProSe function may construct an authorization request message comprising RPAUID set to that of the monitoring MCS UE, Request Type set to “restricted discovery/permission”, and target RPAUID set to that of the announcing MCS UE. The target ProSe function may send the authorization request message towards the ProSe application server. 
     The ProSe application server may acknowledge the target ProSe function by constructing an authorization response message comprising PDUID of the announcing MCS UE which is to be monitored and response type set to “restricted discovery/permission ack” and by sending it towards the target PLMN ProSe function. 
     The target ProSe function constructs a monitor response message compromising ProSe restricted code (or ProSe restricted code prefix with ProSe restricted code suffix pool if restricted direct discovery with application-controlled extension was requested by the announcing MCS UE) and the corresponding validity timer. The target ProSe function may send the monitor response message towards the HPLMN ProSe function. 
     From the ProSe application server, the HPLMN ProSe function has now retrieved the ProSe restricted code (or ProSe restricted code prefix with ProSe restricted code suffix pool if restricted direct discovery with application-controlled extension was requested by the announcing MCS UE) and the corresponding validity timer for each pair of target PDUID-target RPAUID bound with application ID and stored as the user content of the monitoring MCS UE. The HPLMN ProSe function based on the ProSe restricted code (or ProSe restricted code prefix with ProSe restricted code suffix pool if restricted direct discovery with application-controlled extension was requested by the announcing MCS UE) and the corresponding validity timer, allocates a discovery filter with corresponding time-to-live (TTL). 
     The HPLMN ProSe function may construct a discovery response message comprising target RPAUID(s) and the corresponding discovery filter(s) that comprises ProSe restricted code (or ProSe restricted code prefix with ProSe restricted code suffix pool if restricted direct discovery with application-controlled extension was requested by the announcing MCS UE) to be monitored and the corresponding TTL showing how long the filter is valid. If the requested discovery timer in discovery request message sent by MCS monitoring UE was set to zero, the TTL in the discovery response message is set to zero. The discovery response message also comprises discovery entry ID to identify the discovery entity. The HPLMN ProSe function may send the discovery response message towards the monitoring MCS UE. 
     The MCS UE uses the discovery filter to monitor the announcing MCS UE. 
       FIG.  10    is a flow diagram showing an example match reporting procedure. The example procedure for match reporting for announcing/monitoring is as follows: 
     If the monitoring MCS UE has over the air received a ProSe restricted code (or the ProSe restricted code prefix and the ProSe restricted code suffix if the restricted direct discovery with application-controlled extension is used) is matching the discovery filter obtained in the discovery response message from the HPLMN ProSe function but the announcing MCS UE does not have an RPAUID with a valid TTL, the monitoring MCS UE may construct a match report message comprising its own RPAUID, its IMSI or MSISDN as UE identity, discovery type set to “restricted discovery”, application ID set to unique identifier for the application that triggered the monitoring request, the over the air received ProSe restricted code, optional metadata requested, and announcing PLMN ID of the PLMN where the announcing MCS UE was monitored. The monitoring MCS UE transmits the match report message towards the HPLMN ProSe function. 
     The HPLMN ProSe function may verify if the monitoring MCS UE may perform restricted discovery and may analyze ProSe restricted code (or the ProSe restricted code prefix and the ProSe restricted code suffix if the restricted direct discovery with application-controlled extension is used). The HPLMN ProSe function may identify the announcing MCS UE&#39;s RPAUID in the context of the monitoring MCS UE. 
     If metadata requested was included to the originated match report message by the monitoring MCS UE, the HPLMN ProSe function may locate the ProSe application server from the application ID and may construct an authorization request message comprising monitoring MCS UE&#39;s RPAUID, announcing MCS UE&#39;s RPAUID, and request type set to “restricted discovery/match”. The HPLMN ProSe function may send the authorization request message towards the ProSe application server. This step is optional if metadata requested was not included into the original match report message. 
     The ProSe application server may construct an authorization response comprising monitoring MCS UE&#39;s PDUID, announcing MCS UE&#39;s PDUID, response type set to “restricted discovery/match ack”, and metadata corresponding to the Announcing MCS UE. 
     The HPLMN ProSe function may verify that the PDUID belongs to the monitoring MCS UE and the announcing MCS UE&#39;s PDUID are the same as the announcing MCS UE&#39;s PDUID that is stored in the context of the Monitoring MCS UE. 
     The HPLMN ProSe function may construct a match report ack comprising application ID set to unique identifier for the application that triggered the monitoring request, announcing MCS UE&#39;s RPAUID, validity timer, and optionally meta data. 
     The monitoring MCS UE may store the mapping between the ProSe restricted code (or the ProSe restricted code prefix and the ProSe restricted code suffix if the restricted direct discovery with application-controlled extension is used), announcing MCS UE&#39;s PRAUID, the application ID unique identifier of the application that triggered the monitoring procedure, and the related validity timer. 
     The HPLMN ProSe function may construct a Mach Report Info message comprising Monitoring MCS UE&#39;s RPAUID, announcing MCS UE&#39;s RPAUID, announcing MCS UE&#39;s identity set to IMSI or MSISDN for charging purposes, ProSe restricted code (or the ProSe restricted code prefix and the ProSe restricted code suffix if the restricted direct discovery with application-controlled extension is used), and discovery type set to “restricted discovery”. The HPLMN ProSe function may send the match report info message towards the announcing MCS UE&#39;s PLMN ProSe function and the ProSe function of the PLMN where the announcing MCS UE may be roaming in. 
     In Model B, the discoverer MCS UE may use ProSe query code to find the discoveree MCS UE. The discoveree MCS UE may use ProSe response code to identify itself. The ProSe response code is sent by the discoveree MCS UE over the air upon receiving a ProSe query code matching any discovery query filter(s). The discoverer MCS UE discovers then the discoveree MCS UE by matching the ProSe response code to any discovery response filter(s). The ProSe query code, and the discovery response filter(s) are allocated by HPLMN ProSe function to the discoverer MCS UE. The ProSe response code and discovery query filter(s) are allocated by the HPLMN ProSe function to the discoveree MCS UE. 
     Model B compromises procedure for the discoveree MCS UE and procedure for the discoverer MCS UE procedure. It may include matching procedure for the case when the discoverer MCS UE receives ProSe response code over the air that matches the discovery filter provided by the HPLMN ProSe function to the discoveree MCS UE in the discovery response message, however the corresponding RPAUID does not have valid validity timer. Model B is always for restricted discovery. 
       FIG.  11    is a flow diagram showing an example procedures for Model B discovery. The example procedure for the Model B discovery is as follows: 
     Authorization: The MCS UE may get authorized for restricted ProSe direct discovery. In an example, MCS may be public safety and the ProSe direct discovery may be restricted. 
     Discoveree procedure: The discoveree MCS UE may request for discovery and may receive the ProSe response code and associated discovery query filter(s). The discoveree MCS UE may employ the discovery filter(s) to monitor ProSe query code on PC5. The discoveree MCS UE may announce the ProSe response code if receiving a ProSe query code over the air which matches any of discovery filter(s). 
     Discoverer procedure: The discoverer MCS UE may request for discovery and may receive the ProSe query code and associated discovery response filter(s). The discoverer MCS UE may announce the ProSe query code on PC5 interface. The discoverer MCS UE may monitor ProSe response code on PC5 interface that may match any of the discovery response filter(s). The discoverer UE may match-report if having discovered ProSe response code with corresponding PRAUID with no valid validity timer. 
     Example discoveree, discoverer, and match-reporting procedures are explained below with respect to  FIG.  12   ,  FIG.  13   , and  FIG.  14   .  FIG.  12    is a flow diagram showing an example procedure for the discoveree MCS UE. The example procedure for discoveree MCS UE is as follows: 
     The application client in the MCS UE may retrieve the ProSe discovery UE identity (PDUID) and may provide it to the ProSe application server. The ProSe application server may allocate a restricted ProSe application UE identity (RPAUID) for that PDUID, may store the binding between the PDUID and the RPAUID and may return the RPAUID to the application client in the MCS UE. The application client in the MCS UE may store the binding between the RPAUID and its own PDUID and may use those RPAUID to perform discoveree request procedure. 
     The discoveree MCS UE may establish connection to HPLMN ProSe function and may construct a discovery request message comprising RPAUID set to what the MCS UE will announce, UE identity set to IMSI, command indicating this is for discoveree UE, discovery type set to “restricted discovery”, discovery model indicating Model B, application ID set to unique identifier for the application that triggered discovery procedure, discovery entry ID showing the discovery identity that it is a new discovery or an existing one, and PLMN ID of the carrier frequency in announcing PLMN ID if the serving PLMN signaled carrier frequency is not operated by HPLMN or VPLMN and if inter-PLMN ProSe discovery transmission is supported. MCS UE may send the discovery request message to HPLMN ProSe function. 
     HPLMN ProSe function may check for authorization for the MCS application. If there is not any associated MCS UE context, the HPLMN ProSe function may check with HSS and may create a new context for the MCS UE that contains the subscription parameters for this MCS UE. HSS may provide MSISDN of the MCS UE and PLMN ID of where the MCS UE is registered. 
     The HPLMN ProSe function may locate the ProSe application server based on the application ID in the discovery request message and may send an authorization request containing RPAUID and request type set to “restricted discovery/response” towards the ProSe application server. 
     The ProSe application server may answer by an authorization response containing PDUID(s) corresponding the RPAUID stored in the ProSe application server and response type set to “restricted discover/response ack”. 
     The HPLMN ProSe function may verify that at least of one of the PDUID(s) may belong to the discovree MCS UE. The HPLMN ProSe function may assign a ProSe response code and ProSe query code with the associated discovery query filter(s). The ProSe response code corresponds to the RPAUID in the discovery request and the HPLMN ProSe function may assign an associated validity timer for the ProSe response code and ProSe query code with the associated discovery query filter(s). The validity timer identifies the duration of validity of the ProSe response code and ProSe query code with the associated discovery query filter(s). The discoveree MCS UE may use this ProSe response code within this validity duration if PLMN is not changed. The HPLMN ProSe function may store ProSe response code with its associated validity timer and ProSe query code with associated discovery query filter(s) in the context of the MCS user. 
     If the discovery request is authorized, HPLMN ProSe function may construct announce authorization message containing RPAUID, MCS application ID, ProSe response set to assigned code for this request, UE ID set to IMSI or MSISDN, discovery entry ID to identify the discovery entry, and validity timer indicating how long the ProSe response code will be valid. The HPLMN ProSe function may send the announce authorization message towards the VPLMN ProSe function. 
     The VPLMN ProSe function may acknowledge the HPLMN ProSe function that it authorizes the MCS UE to perform restricted discovery announcing if the announce authorization message contain a new discovery entry ID. If the discovery entry ID already exists, the VPLMN ProSe function may acknowledge the update as requested i.e. updating the discoveree MCS UE&#39;s discovery entry by the new ProSe response code and its associated validity timer. 
     The HPLMN ProSe function may construct a discovery response message with discovery type set to Model B, ProSe response code, discovery query filter(s) suited for certain ProSe Query code, validity timer associated to ProSe response code and the discovery query filter(s), and discovery entity ID to identify the discovery identity. The MCS discoveree UE may use the discovery query filter(s) (which may be multiple) to determine which ProSe query code triggers that the MCS discoveree UE announces the assigned ProSe response code. The HPLMN ProSe function may send the discovery response message towards MCS discoveree UE. 
     The MCS discoveree UE may use the discovery query filter(s) which many be multiple to determine which ProSe query code triggers that the MCS discoveree UE announces the assigned ProSe response code. If the validity timer expires, the MCS discoveree ue may send a new discovery request message towards the HPLMN ProSe function. 
       FIG.  13    is a flow diagram of an example procedure. The procedure for discoverer MCS UE is as follows: 
     The application client in the MCS UE may retrieve the ProSe discovery UE identity (PDUID) and may provide it to the ProSe application server. The ProSe application server allocates a restricted ProSe application UE identity (RPAUID) for that PDUID, may store the binding between the PDUID and the RPAUID and may return the RPAUID to the application client in the MCS UE. The MCS UE may obtain RPAUIDs of those MCS target users from the ProSe application server passed in an application level container. RPAUID instead of PDUID may be used for public safety feature MCS. 
     The discoverer MCS UE may establish connection to the MPLMN ProSe function and may construct a discovery request message comprising RPAUID set to what the discoverer MCS UE wants to announce, UE identity set to IMSI, command showing this is for ProSe query procedure, discovery type set to “restricted discover”, discovery model set to Model B, application ID set to unique identifier for the application that triggered discovery procedure, application level container compromising the target RPAUIDs that the MCS UE is to discover, discovery entry ID showing the discovery identity that it is a new discovery or an existing one, and the optional requested discovery timer. The requested discovery timer is set to zero to indicate HPLMN to delete the discovery filter(s) for that discovery entry ID. The MCS UE may send the discovery request message towards HPLMN ProSe Function. 
     HPLMN ProSe function may check for authorization for the MCS application. If there is not any associated MCS UE context, the HPLMN ProSe function may check with HSS and may create a new context for the MCS UE that contains the subscription parameters for this MCS UE. HSS may provide MSISDN of the MCS UE and PLMN ID of where the MCS UE is registered. 
     The HPLMN ProSe function may locate the ProSe application server based on the application ID in the discovery request message and may send an authorization request containing RPAUID, request type set to “restricted discovery/query”, and application level container towards the ProSe application server. 
     The ProSe application server may construct an authorization response comprising target PDUIDs and corresponding target RPAUID that the RPAUID in the authorization request may discover, PDUID of the requesting MCS UE, and response type set to “restricted discovery/query ack”. The ProSe application server may send the authorization response towards the HPLMN ProSe function. 
     The HPLMN ProSe function may allocate the context for the discoveree UE(s) if the PLMN ID in the target PDUID-target RPAUID corresponds to a valid ProSe response code. The HPLMN ProSe function may allocate the discovery response filter(s) which trigger the MCS discoveree UE to transmit the ProSe response code. This procedure has expiration time which is specified by validity timer. 
     The HPLMN ProSe function may construct a discovery request message comprising RPAUID of discoveree MCS UE, UE identity set to IMSI or MSISDN, target PDUID and corresponding target RPAUID, application ID set to unique identifier for application that triggered the discovery procedure, and discovery entry ID to identify the discovery entry being new or an existing one. The HPLMN ProSe function may send the discovery request towards the target PLMN ProSe Function which belongs to the discoveree MCS UE. If the discovery entry ID is an existing one, the Target PLMN ProSe function may modify the existing discovery procedure with the parameters included in the discovery request message. 
     The target ProSe Function has an option to construct an authorization request message comprising RPAUID set to that of the discoverer MCS UE, Request Type set to “restricted discovery/query”, and target RPAUID set to that of the discoveree MCS UE. The target ProSe function may send the authorization request message towards the ProSe application server. 
     The ProSe application server may acknowledge the target ProSe function by constructing an authorization response message comprising PDUID of the discovery MCS UE, response type set to “restricted discovery/query ack”, and target PDUID of the discoveree MCS UE. The ProSe application server may send the authorization response message towards the target PLMN ProSe function. 
     The target PLMN ProSe function may allocate the context of the discoveree MCS UE based on target PDUEID-target RPAUID and the application ID. The target PLMN ProSe function may respond with a discovery response comprising ProSe query code which will be used by HPLMN ProSe function to build the discovery query filter so that it triggers the discoveree UE to send ProSe Response code, the actual ProSe response code, and validity timer to indicate for how long the ProSe Query code and ProSe response code are valid. 
     The HPLMN ProSe function may construct an announce authorization message comprising RPAUID of the discovery MCS UE, application ID, ProSe query code and its associated validity timer, UE identity set to IMSI or MSISDN of discovery MCS UE for charging purposes in the visiting domain, and discovery entry ID to identify the discovery entry. The HPLMN ProSe function may send the announce authorization message towards the VPLMN ProSe function. 
     The VPLMN may acknowledge that it authorizes the discovery MCS UE to perform ProSe direct discovery procedure. If the discovery entry ID in the announce authorization message corresponded an already discovery entry, the VPLMN ProSe function may acknowledge the replacement of the existing ProSe query code and its associated validity timer. 
     The HPLMN ProSe function may construct the discovery response message comprising discovery model set to Model B, ProSe query code, one or multiple discovery response filters which are generated by the HPLMN ProSe function based on ProSe response code, and validity timer for how long the ProSe query code and discovery response filter(s) are valid. The HPLMN ProSe Function may transmit the Discovery Response message to the Discoverer MCS UE. 
     The discoverer MCS UE may obtain the information from the discovery response message to discover discoveree MCS UE. If the validity timer is expired, the discoverer MCS UE may send a new discovery request message towards the HPLMN ProSe function. 
       FIG.  14    is a flow diagram showing an example matched reporting procedure. An example procedure for match reporting for discoveree/discoverer is as follows: 
     If the discoverer MCS UE may have received over the air a ProSe response code is matching the discovery response filter obtained in the discovery response message from the HPLMN ProSe function but the discoveree MCS UE does not have an RPAUID with a valid TTL, the discoverer MCS UE may construct a match report message comprising its own RPAUID, its IMSI or MSISDN as UE Identity, discovery type set to “restricted discovery”, application ID set to unique identifier for the application that triggered the monitoring request, the over the air received ProSe response code, optional metadata requested, and discoveree PLMN ID of the PLMN where the discoveree MCS UE was discovered. The discovere MCS UE may transmit the match report message towards the HPLMN ProSe Function. 
     The HPLMN ProSe function may verify if the discoverer MCS UE has performed restricted discovery and may analyze Prose response code. The HPLMN ProSe function may identify the discoveree MCS UE&#39;s RPAUID in the context of the discoverer MCS UE. 
     If metadata requested was included to the originated match report message by the discoverer MCS UE, the HPLMN ProSe function may locate the ProSe application server from the application ID and may construct an authorization request message comprising discoverer MCS UE&#39;s RPAUID, discoveree MCS UE&#39;s RPAUID, and request type set to “restricted discovery/match”. The HPLMN ProSe function may send the authorization request message towards the ProSe application server. This step is optional if metadata requested was not included into the original match report message. 
     The ProSe application server may construct an authorization response comprising discoverer MCS UE&#39;s PDUID, discoveree MCS UE&#39;s PDUID, response type set to “restricted discovery/match ack”, and metadata corresponding to the discoveree MCS UE. 
     The HPLMN ProSe function may verify that the PDUID belongs to the discoverer MCS UE and the discoveree MCS UE&#39;s PDUID are the same as the discoveree MCS UE&#39;s PDUID that is stored in the context of the discoverer MCS UE. 
     The HPLMN ProSe function may construct a match report ack comprising application ID set to unique identifier for the application that triggered the discovery request, discoveree MCS UE&#39;s RPAUID, validity timer, and optionally meta data. 
     The discoverer MCS UE may store the mapping between the ProSe response code, discoveree MCS UE&#39;s PRAUID, the application ID unique identifier of the application that triggered the discovery procedure, and the related validity timer. 
     The HPLMN ProSe Function may construct a match report info message comprising discoverer MCS UE&#39;s RPAUID, discoveree MCS UE&#39;s RPAUID, discoveree MCS UE&#39;s Identity set to IMSI or MSISDN for charging purposes, ProSe response code, and discovery type set to “restricted discovery”. The HPLMN ProSe function may send the match report info message towards the discoveree MCS UE&#39;s PLMN ProSe function and the ProSe function of the PLMN where the discoveree MCS UE may be roaming in. 
       FIG.  15    is a block diagram of an example MCS UE-to-network relay. A public safety ProSe (MCS) UE may provide the functionality to support connectivity to the network for a remote MCS UE. An MCS UE is considered to be remote if it has established a successful PC5 link connection to a UE-to-Network relay. A remote MCS UE may be out of E-UTRAN coverage. An MCS UE may be within a coverage of E-UTRAN and may choose not to use E-UTRAN coverage. At the time of discovery ProSe relay service codes for MCS services in the MCS UE-to-Network relay are recognized by the remote MCS UE to identify the MCS UE-to-Network relay. Relay service codes are pre-provisioned in the MCS UE-to-Network relay and the remote MCS UE and are communicated by discovery announcement message for Model A ProSe discovery and by discovery solicitation message/discovery response message for Model B ProSe discovery. The remote MCS UE employs the MCS UE-to-Network relay to access E-UTRAN and thereby performing IMS registration and also MCS session establishment. 
     The MCS UE-to-Network relay may function as a relay for unicast traffic between remote UE and the network by relaying any IP traffic to the UE. The MCS UE-to-Network relay may function as a relay for multicast broadband multicast service (MBMS) traffic using one ProSe Direct Communication. 
     In this context, the MCS UE may be represented by a remote MCS UE and a UE-to-Network MCS UE which have PC5 interface to each other. This may be transparent to the E-UTRAN network and/or IMS network. 
     To set up an on-network MCS media session, the MCS UEs may register with IP Multimedia Subsystem (IMS) network. At the time of registration to the IMS network, an MCS UE may register its supported IMS communication service it intends to use. The MCS UE may also register its supported IMS applications it intends to use at the time of IMS registration. The IMS maintain the information the UE&#39;s capabilities for the possible session setup by a third party entity or another MCS UE. A third party entity may like to get a MCS UE&#39;s capabilities from the operator&#39;s network where MCS UE has registered to, in order to e.g. provide a service or application. A third party entity may transmit a session initiation protocol (SIP) message (e.g. SIP INVITE request) to the UE to set up a session. Therefore, the network must know the MCS UE&#39;s capabilities to provide this information to the third party entity. 
       FIG.  16    is a flow diagram showing an example IMS registration procedure of an MCS UE. This example flow diagram shows: MCS UE may send a SIP REGISTER request containing MCS feature tag in contact header field towards the P-CSCF in the visiting network. P-CSCF may use the MCS UE&#39;s ID to locate the I-CSCF in the home network by DNS query. I-CSCF in the home network may select suitable S-CSCF with help of HSS. S-CSCF may challenge the registration by requesting an authentication. If the authentication information is not valid, S-CSCF may get it from HSS. MCS UE may provide authentication response and may send the SIP REGISTER request containing authentication response and the MCS feature tag in the contact header towards the P-CSCF in the visiting network. P-CSCF may use the MCS UE&#39;s ID to locate the I-CSCF in the home network by DNS query. I-CSCF in the home network may select suitable S-CSCF with help of HSS. S-CSCF may authenticate the MCS UE and may send registration notification to the HSS and may receive the MCS user profile from the HSS. The MCS user profile may be used for the 3rd party register to the MCS application server (AS). S-CSCF may respond to OK to the MCS UE. 
     MCS signaling may be enhanced to support advanced call capabilities. In an example embodiment, enhanced MCS calls may include capabilities such as audio, video, data, full duplex, dispatching, and/or administering. To avoid or reduce any possible compatibility issues, new service or application identifiers may be implemented for the additional capabilities. An example embodiment, enhances ICSI to indicate different capabilities for MCS e.g. audio, video, data, full duplex, dispatching, and/or administering capabilities. One or more IMS service parameters be communicated during the registration process to indicate at least one MCS capability to a network server, e.g. a proxy server, a registrar server. 
     A wireless device may register one or more IMS communication service identifiers (ICSIs) of push-to-talk (e.g. mission critical PTT) in a wireless network. One of the one or more ICSIs may indicate at least one of audio, video, data, full duplex, dispatching, and/or administering capabilities of the wireless device. ICSI may be in the form of a media feature tag. A feature tag may indicate one or more capability of the wireless device. For, example a specific feature tag, such as 3gpp-service.ims.icsi.mcpttvideo may indicate video capability. This is an example, other features tag names may be used. One or more ICSI may indicate a combination of at least two of audio, video, data, full duplex, dispatching, and/or administering capabilities of the wireless device. For example, a feature tag 3gpp-service.ims.icsi.mcpttmedia, may indicate capability for both audio and video. 
     In another example, one or more additional parameters may be included in the registration message along with a feature tag to indicate the wireless device capability or a combination of one or more capabilities of the wireless device. 
     In an example, the wireless device may transmit the registration message to a UE relay which relays message(s) to a network node. The wireless device may discover the UE relay using discovery model A or model B. In an example, the UE relay may decode the registration message and may update the message headers before retransmitting the message. The UE relay may update the source and destination address in the registration message. 
     In an example, the registration message may further register one or more IMS application reference identifiers (IARIs). One of the one or more IARIs may indicate at least one of audio, video, data, full duplex, dispatching, and/or administering capabilities of the wireless device. IARI may be in the form of a media feature tag. A feature tag may indicate one or more capability of the wireless device. For, example a specific feature tag, such as 3gpp-application.ims.iari.mcpttvideo may indicate video capability. This is an example, other features tag names may be used. One or more IARI may indicate a combination of at least two of audio, video, data, full duplex, dispatching, and/or administering capabilities of the wireless device. For example, a feature tag 3gpp-application.ims.iari.mcpttmedia, may indicate capability for both audio and video. 
     In an example embodiment, the wireless device may register one or more IMS application reference identifiers (IARIs) of push-to-talk in a wireless network. One of the one or more IARIs indicates at least one of audio, video, data, full duplex, dispatching, and/or administering capabilities of the wireless device. In an example, the one or more IARIs may indicate a combination of at least two of audio, video, data, full duplex, dispatching, and/or administering capabilities of the wireless device. The wireless device may further registering one or more IMS communication service identifiers (ICSIs). One of the one or more ICSIs may indicate at least one of video and data capabilities of the wireless device. 
     In an example, the wireless device may register one or more IMS service parameters in a wireless network. The one or more IMS service parameters may indicate a combination of at least two of audio, video, data, full duplex, dispatching, and/or administering capabilities of the wireless device. The one or more IMS service parameters may indicate at least one of audio, video, data, full duplex, dispatching, and/or administering capabilities of the wireless device. 
       FIG.  17    is a flow diagram of an example IMS registration of an MCS UE. MCS UE may register its supported IMS communication services and IMS applications, it may intent to use to its contact header field of the register message when registering to the IMS network. IMS network may locate the most suitable S-CSCF for this registration and may forward the registration request to that S-CSCF. S-CSCF may challenge the MCS UE by sending authentication request to the UE. MCS UE may respond to the authentication request. S-CSCF 3rd part may register the UE to the MCS AS. 
     A wireless device may register one or more IMS communication service identifiers (ICSIs) a wireless network. one of the one or more ICSIs may indicate at least one of video and data capabilities of the wireless device. 
     MSC group calls and MCS private calls may include capabilities such as, for example, video and data. Some releases may comprise audio related requirements and/or generic requirements for MCS. New capabilities may result in compatibility issue at the time of session setup if the UEs are from different release or from the same release but having different capabilities. Embodiments avoid incompatibilities between releases. 
     In some example cases, network (e.g. the registrar or application servers, and/or third party application servers, and/or other network entities) may desire to know the MCS UE&#39;s capabilities in terms of supported services and applications. A network node may transmit a request to a registrar and/or network node storing MCS UE capability and request for MCS UE capabilities. The network node may transmit a response message to the requester (directly or indirectly) indicating the MCS UE capabilities of the UE. The network nodes may communicate (transmit/receive) the MCS user&#39;s capabilities by exchanging SIP message(s) (e.g. INVITE, MESSAGE). The network node may transmit a SIP message (e.g. SIP INVITE request) to the UE to set up a session to stream a video clip to the MCS UE. Thus the network may desire to know if the MCS UE has the capability to receive it. The network node may transmit a SIP message (e.g. SIP MESSAGE request) to the UE to set up a session to send information about multicast bearer and the related ports for media reception. Thus, the network may desire to know about the MCS UE&#39;s capabilities to receive the multicast media. 
     A third party entity may like to get a MCS UE&#39;s capabilities from the operator&#39;s network where MCS UE has registered to, in order to e.g. provide a service or application. A third party entity may transmit a SIP message (e.g. SIP INVITE request) to the UE to set up a session. Therefore, the network must know the MCS UE&#39;s capabilities to provide this information to the third party entity. The UE may response to the SIP message. The network/third party may subsequently start communicating and transmitting/receiving data, audio, and/or video to/from the MCS UE. 
     New Dialog or Standalone Transaction: Once the MCS UEs are all registered to the IMS network and if an MCS UE may like to establish an MCS media session, the MCS UE may declare all its supported IMS communication services and all it supported IMS applications it intends to use. If this is a request for a new dialog, a SIP header field may be populated comprising a public GRUU value, a temporary GRUU value, or SIP URI containing the contact address of the MCS UE; an “ob” SIP URI parameter; an indicator for IMS communication service that the MCS UE may include in media feature tag; and an indicator for IMS application that the MCS UE may include in a media feature tag. 
     When an MCS UE receives ICSI values corresponding to the IMS communication services that the network provides to the user, if the MCS UE constructs a request for a new dialog or standalone transaction and the request is related to one of the ICSI values, the MCS UE may populate a P-Preferred-Service header field with one of the ICSI values. In construction of the same request for a new dialog and standalone transaction, the MCS UE may populate an Accept-Contact header field comprising an ICSI value which may differ from the one added to P-Preferred-Service header field. In construction of a request for a new dialog or standalone transaction, the MCS UE may populate an Accept-Contact header field comprising an IARI value if an IMS application indicates that an IARI is to be included in a request 
     The MCS UE may modify the established dialog capabilities by e.g. adding a media or requesting a supplementary service if the modification is defined for the IMS communication service. If the modification is not defined for that IMS communication service, the MCS UE may initiate a new dialog. 
       FIG.  18    is a flow diagram shows an example MCS group session setup by MCS UE. MCS UE  1  may initiate an MCS group session with MCS UE  2  and MCS UE  3  by sending an SIP INVITE request which may comprise MCS feature tag in a SIP header field. The SIP header field may also comprise the MCS feature tag which may indicate that MCS service may be required for the MCS group session. IMS may validate the service profile of the MCS UE  1  and may evaluate the filter criteria. It may thereafter forward the invite towards MCS AS. MCS AS may accept the MCS group session and may invite MCS UE  2  and MCS UE  3  by sending an SIP INVITE request which may comprise MCS feature tag in the SIP header field. The SIP header field may also comprise the MCS feature tag which may indicate that MCS service may be required for the MCS group session. HSS may be queried to locate MCS UE  2  and MCS UE  3  and IMS may validate their service profile and may evaluate the filter criteria. MCS UE  2  and MCS UE  3  may accept the invitation for the MCS group session. IMS may notify the MCS UEs that other MCS UEs have now joined the on-network MCS group session. 
     MCS calls may include audio. According to embodiments, MCS signaling may be enhanced to support advanced call capabilities. In an example embodiment, enhanced MCS calls may include capabilities such as audio, video and/or data. To avoid or reduce compatibility issues, new service or application identifiers may be implemented for the additional capabilities. An example embodiment, enhances ICSI to indicate different capabilities for MCS, such as, dfor example, audio, video, and/or data capabilities. One or more IMS service parameters may be communicated during the new dialog establishment procedure and/or standalone transaction process to indicate at least one MCS capability to a network server, for example, a proxy server, a registrar server. 
     The wireless device may employ one or more IMS communication service identifiers (ICSIs) for new dialogs establishment or standalone transactions in a wireless network. One of the one or more ICSIs may indicate at least one of audio, video, data, full duplex, dispatching, and administering capabilities of the wireless device. ICSI may be in the form of a media feature tag. A feature tag may indicate one or more capability of the wireless device. For, example a specific feature tag, such as 3gpp-service.ims.icsi.mcpttvideo may indicate video capability. This is an example, other features tag names may be used. One or more ICSI may indicate a combination of at least two of audio, video, data, full duplex, dispatching, and administering capabilities of the wireless device. For example, a feature tag 3gpp-service.ims.icsi.mcpttmedia, may indicate capability for both audio and video. 
     In another example, one or more additional parameters may be included in the new dialog establishment or a standalone transaction along with a feature tag to indicate the wireless device capability or a combination of one or more capabilities of the wireless device. In an implementation, the wireless device may transmit the message to establish a new dialog or as a standalone transaction to a UE relay which relays to message to a network node. The wireless device may discover the UE relay using discovery model A or model B. In an example, the UE relay may decode the message for new dialog establishment or for the standalone transition and may update the message headers before retransmitting the message. The UE relay may update the source and destination address in the registration message. 
     In an example, the message for the new dialog and the standalone transaction may further employ one or more IMS application reference identifiers (IARIs). One of the one or more IARIs may indicate at least one of audio, video, data, full duplex, dispatching, and administering capabilities of the wireless device. IARI may be in the form of a media feature tag. A feature tag may indicate one or more capability of the wireless device. For, example a specific feature tag, such as 3gpp-application.ims.iari.mcsvideo may indicate video capability. This is an example, other features tag names may be used. One or more IARI may indicate a combination of at least two of audio, video, and data capabilities of the wireless device. For example, a feature tag 3gpp-application.ims.iari.mcsmedia, may indicate capability for both audio and video. 
     In an example embodiment, the wireless device may employ one or more IMS application reference identifiers (IARIs) of push-to-talk in a wireless network for establishment of a new dialog or for standalone message. One of the one or more IARIs may indicate at least one of audio, video, data, full duplex, dispatching, and administering capabilities of the wireless device. In an example, the one or more IARIs may indicate a combination of at least two of audio, video, data, full duplex, dispatching, and administering capabilities of the wireless device. The wireless device may further employ one or more IMS communication service identifiers (ICSIs) for establishing new dialog or standalone message. One of the one or more ICSIs may indicate at least one of audio, video, data, full duplex, dispatching, and administering capabilities of the wireless device. 
     In an example, the wireless device may employ one or more IMS service parameters in a wireless network for establishing a new dialog or a standalone message. The one or more IMS service parameters may indicate a combination of at least two of audio, video, data, full duplex, dispatching, and administering capabilities of the wireless device. The one or more IMS service parameters indicate at least one of audio, video, data, full duplex, dispatching, and administering capabilities of the wireless device. 
     In an example, the embodiments may include enhanced service identifiers representing new services. In an example, the embodiments may include enhanced application identifiers that represent applications for the MCS service(s). In an example embodiment, enhanced service identifiers for MCPTT, MCPTT video, and MCPTT data maybe employed to maintain interoperability with various releases 
       FIG.  19    is a flow diagram of an example MCS session setup by MCS UE A. MCS UE  1  may initiate an MCS session with other MCS UEs by sending an SIP INVITE request which may comprise MCS related IMS communication service and IMS application in the SIP header field. IMS may validate the service profile of the MCS UE  1  and may locate the suitable S-CSCF to process the MCS session invitation. S-CSCF may forward the invitation to the MCS AS which may generate separate invitations towards other MCS UEs who were originally invited by MCS UE  1 . The invited MCS UEs may analyze the capabilities of MCS UE  1  who invited them to the MCS session and may make decision to join the MCS session based on the requested capabilities by MCS UE  1 . IMS may notify MCS UEs that other MCS UEs have joined the MCS group session and the on-network MCS group session is now established. 
     In other case an MCS UE may desire to identify its capabilities for new dialogs or a standalone transaction. For instance: an MCS UE may like to inform the end MCS UE that it is capable of voice session while using packet switch. An MCS UE may like to share information that it is capable of audio emergency call and not video emergency call. An MCS UE A may like to setup a video capable MCS group call with MCS UE B, MCS UE C, and MCS UE D. MCS UE A may send a SIP INVITE request message to MCS Application Server (AS) indicating the video capabilities for this MCS group call. 
     MCS UE A may be a legacy MCS UE which does not support video or data. MCS UE B with video capabilities realizes that MCS UE A is a legacy MCS UE at the time of session setup. Thus, there may not be any backward incompatibility issue. 
     An MCS UE (in IMS) may transmit (e.g. share) its capabilities with the network and the end MCS UE by adding service feature tags and application feature tags to the SIP requests. 
     Example embodiments of mission critical push-to-talk (MCPTT) describe mechanisms for handling group and/or organization affiliation of an MCPTT user to MCPTT groups and/or organizations. MCPTT is an example of MCS. The disclosed embodiments for MCPTT may also be implemented in PTT (push to talk) type calls. In the disclosed embodiment, PTT may be considered as an example of a MCPTT type call. A non-limiting example context in which the embodiments may be implemented is 3GPP MCPTT standards. Some or more of the features described in the standards may be implemented and some others may be optional and may not be implemented in example embodiments. 
     One of the more of the following features may be features for on-network and/or off-network MCPTT. An MCPTT user may be able to affiliate with a multiplicity of MCPTT groups, subject to restrictions configured by the MCPTT administrator. An MCPTT User with limited speaker resources (e.g., a handheld UE) might find that playing out concurrent received audio/data/media from multiple active MCPTT groups becomes confusing and may also cause undesired voice/data/media distortion for the receiving user. During periods of time when the MCPTT user is receiving audio from multiple MCPTT groups, which MCPTT group&#39;s audio is presented to the MCPTT user is determined by the MCPTT user&#39;s choice, the priority associated with the talker of the selected MCPTT group(s), other considerations or combinations of these. The MCPTT UE may be aware of the active groups to which the MCPTT user has affiliated or selected and the identity of the other active receiving groups is available for display on the MCPTT UE. When the receive activity from the Selected MCPTT group stops, the MCPTT UE may present the audio from the next group per the MCPTT user&#39;s choice or by other means. 
     The MCPTT service may provide that if there is an MCPTT emergency group call on one of the MCPTT groups that an MCPTT user is affiliated to, but that user is already in a lower priority MCPTT group call or private call (with floor control), that the MCPTT user automatically hears the MCPTT emergency group call. Depending on the MCPTT User&#39;s settings and/or the MCPTT UE capability the above feature may imply that the MCPTT user stops receiving from another MCPTT group (which may normally have a higher priority) or a private call (with floor control). 
     One or more of the following features may apply to on-network MCPTT. In an example, some of these features may also implemented in an off-network MCPTT. The MCPTT service may provide the user ID, associated user ID alias(es), group ID, group aliases and, if available, the identity of the mission critical organization name of the transmitting participant to the receiving MCPTT UEs unless the transmitting participant&#39;s identity is restricted. The MCPTT service may provide the user ID and/or associated aliases, the identity of the selected MCPTT group, and, if available, the identity of the mission critical organization name of the transmitting MCPTT user to MCPTT UEs that are receiving for display by each MCPTT UE. 
     In an example embodiment, the features may include one or more of the following. An MCPTT UE operating off the network may be capable of transmitting the user ID, alias(es), off-network MCPTT group and, if available, mission critical organization name of the user who is talking (i.e., whose UE is transmitting) to all other users in the call including MCPTT UEs operating off the network that enter the call late. 
     In an example road accident case, an MCPTT user may be involved in group calls from several MCPTT groups such as police department, fire department, and critical medical department. The MCPTT user may be notified if a higher priority call is held by a group that the MCPTT user is most affiliated with. For instance, if a fire fighter who is affiliated with the above three MCPTT groups at a time of the road accident, receives a call from the fire department, the fire fighter may be able to be interrupted by fire department in case of an emergency. Thus, it is necessary for the MCPTT users to be aware of other MCPTT users&#39; identities, group identities, and organization identities. 
     In an example embodiment, MCPTT users within an MCPTT group call may need to be aware of the user-ID, group-ID and/or organization ID of the MCPTT user who is the current talker (e.g. the user that is talking, sending data, and/or media). During the discovery, the MCPTT user may be permitted to discover MCPTT users from the affiliated MCPTT groups. The information about the other MCPTT user ID, group ID and organization ID may not be provided from the discovery procedure. In the on-network MCPTT case, this may be resolved by network engagement in the MCPTT call setup. 
     In the case when an MCPTT user is engaged in several affiliated group calls in an on-network MCPTT call, the MCPTT group call administrator may handle the engagement of the MCPTT user in different affiliated MCPTT group calls. If an audio media needs to be interrupted to pass another audio media, the MCPTT group call administrator may handle that due to the e.g. agreed rules and/or policies for MCPTT affiliated group calls. 
     LTE Release 13 of the mission critical service comprise voice communication and may be called mission critical push to talk (MCPTT). MCPTT may enable the group members of the critical services such as fire department, police department, and/or emergency medical service to setup one to one or one to many voice communications. In release 13, the MCPTT may be based on on-network and/or off-network. The on-network MCPTT may use an IMS platform in combination with LTE infra structure for the mission critical voice service (MCPTT), while off-network MCPTT may be based on direct communication among group members. The MCPTT may employ a floor control to enable the group members uninterruptedly talk unless they are interrupted by another member or a dialog with higher hierarchy/priority. 
     Release 14 of mission critical services may additionally comprise new services. These new services for mission critical communications may be based on video and data communications. For the video and data communications, the floor control may comprise additional concepts that the voice services. Example embodiments assumes various floor control functionalities for the video and data transmission. The floor control may have the same functionality as it does for the audio transmission (MCPTT) or may have different functionalities from it. According to an embodiment, the floor control for video and data transmission may not exist. 
     Example embodiments may be applicable to other services in addition to mission critical services. For example, example embodiments may be implemented in a video conference call service, video call service, and non-emergency audio and/or video calls (such as a conference call). 
       FIG.  20    is an example block diagram of an architecture configured to support an on-network Mission critical push to talk (MCPTT) service(s). Elements and interfaces of the architecture may be defined and specified in the release 13 of 3GPP TS 23.179. On-network MCPTT may involve group members in one-to-one or one-to-many voice communications. When a floor control is implemented, the MCPTT group call members may receive voice media from one MCPTT sender, thus a media mixer may not be needed. The functionality of a media mixer may be used when the MCPTT participant listening to several MCPTT group calls or when there is not any floor control within the same group call. 
       FIG.  21    illustrates an example architecture configured to support MCVideo. An MCVideo UE may register to an IMS to get access to an MCVideo service. The architecture may also provide a choice for broadcast toward MCVideo UEs. The MB 2  reference point may provide an ability for an MCVideo AS to request allocation of temporary mobile group identifiers (TMGIs) from a broadcast multicast service center (BM-SC). The MB 2  reference point may provide an ability for the MCVideo AS to request deallocation of TMGIs from BM-SC. The MB 2  reference point may provide the ability for an BM-SC to report the status of a multicast broadcast multicast service (MBMS) bearer to the MCVideo AS. An MCVideo-1 reference point may provide an ability for the MCVideo AS to send information about connectivity to a broadcast bearer to the MCVideo UE. The MCVideo-1 reference point may provide the ability for the MCVideo UE to send information about broadcast multicast coverage to the MCVideo AS. 
       FIG.  22    is an example architecture configured to support on-network MCVideo service(s). An MCVideo-1 reference point may exist between an MCVideo server and an MCVideo client and may comprise a SIP interface and/or an HTTP interface. This reference point may be used for MCVideo application signaling in establishing an MCVideo session. This reference point may also be employed by a UE to provide its location to the MCVideo server for the multicast/broadcast services. According to an embodiment, an MCVideo-2 reference point may exist between a MCVideo server and MCVideo user database and may be an Sh reference point in 3GPP TS 23.002 and may be employed to obtain specific user data for an MCVideo user. According to an embodiment, an MCVideo-3 reference point may exist between the MCVideo server and other MCVideo server. According to an embodiment, an MCVideo-4 reference point may exist between a transmission control server for participant transmission and may provide similar and/or functionalities such as floor control functionality over a multicast bearer. According to an embodiment, an MCVideo-5 reference point may exist between media distribution function and an EPS to obtain unicast media bearers with appropriate QoS from the EPS. If an MCVideo employs an internet protocol multimedia subsystem (IMS), this functionality of a media distribution function may exist in proxy-call session control function (P-CSCF). According to an embodiment, an MCVideo-6 reference point may exist between an MCVideo server and the EPS and may be employed to request the allocation and activation of multicast transport resources for MCVideo. According to an embodiment, an MCVideo-7 reference point may exist between media distribution function and media mixer and may be employed to exchange unicast media. The MCVideo-7 reference point may use the SGi reference point in 3GPP TS 23.002. According to an embodiment, an MCVideo-8 reference point may exist between the media distribution function and the media mixer and may be employed for multicast media distribution from the MCVideo server to the MCVideo UE. The MCVideo-8 reference point may employ the MB 2 -U reference point defined, for example, in 3GPP TS 23.468. According to an embodiment, an MCVideo-9 reference point may exist between a transmission control server to a transmission participant and may provide similar and/or functionalities such as floor control functionality over a multicast bearer. According to an embodiment, other reference points may be similar to the ones defined for the MCPTT service the release 13 of 3GPP TS 23.179. Some parts of  FIG.  22    are shown by dashed line indicating that their functionalities may be different from the ones in MCPTT. 
       FIG.  23    is an example flow diagram of a mission critical session setup as per an embodiment. A mission critical (MC) UE  1  may register as to the IMS network and thereby to an MCVideo/MCAudio/MCPTT service. At the time of registration, dialog, and standalone transaction, MC UE  1  may employ ICSI and IARI to indicate its capabilities. At the time of the session setup with MC UE  2 , MC UE  1  may use IMS communication service indicator (ICSI) and/or IMS application reference indicator (IARI) registered to MCVideo/MCPTT/MCAudio in Contact header field, P-Preferred-Service header field, and/or Accept-Contact header field to indicate its capabilities for MCVideo/MCPTT/MCAudio. According to an embodiment, MC UE  1  may send a session invitation towards MC UE 2  via IMS network and the MC AS, adding ICSI and/or IARI registered to MCVideo/MCPTT/MCAudio as feature tag to Contact header field, P-Preferred-Service header field, and/or Accept-Contact header field to indicate its capabilities for MCVido/MCPTT/MCAudio. According to an embodiment, MC UE  2  may accept the invitation by sending an “OK” towards MC UE  1  via IMS network and the MC AS. According to an embodiment, MC UE  1  may acknowledge the acceptance by sending an “ACK” towards MC UE  2  via IMS network and the MC AS. According to an embodiment, a mission critical media session may be established between the MC UE  1  and MC UE  2 . Within that MC media session, the video/audio packets may be exchanged between the MC UEs. 
       FIG.  24    is an example flow diagram of an Internet protocol connectivity access network (IP CAN) session setup as per an embodiment. In one example embodiment, MC UE  1  may set up the IP connectivity for MCVideo session according to  FIG.  24   . 
       FIG.  24    illustrates an example embodiment while the default EPS bearer with QoS class identifier (QCI) level  69  since it is for mission critical service signaling is established. The MC UE  1  may send a session setup request towards the application function (AF) to setup the MC audio and/or video bearers employing IMS communication service indicator (ICSI) and/or IMS application reference indicator (IARI) registered to MCVideo in Contact header field, P-Preferred-Service header field, and/or Accept-Contact header field to indicate its capabilities for the MCVideo session. The AF may initiate the IP-CAN session initiation procedure. The AF may use a new dedicated MCVideo attribute value pairs (AVP) indicator in the diameter AA-request transmitted by the MCVideo AF towards the PCRF. The PCRF may receive the MCVideo AVP and may attempt to trigger the IP-CAN to enable assigned resources for initiation of the MCVideo session. The PCRF may send a DIAMETER: setup bearer request comprising a PCC decision provision (QoS policy) which may request the MCVideo user&#39;s location information and MCVideo UE time zone toward the PDN-GW. The PDN-GW may employ the policy to adjust the EPS bearer QoS and may generate the traffic flow template (TFT). The PDN-GW may create GTP: create bearer request message comprising procedure transaction identifier (PTI) for GTP: create bearer request, EPS bearer identity, EPS bearer QoS, APN-AMBR, and TFT. The PDN-GW may send the GTP: create bearer request toward the S-GW. The S-GW may send GTP: create bearer request message comprising PTI, EPS bearer identity, EPS bearer QoS, TFT, and APN-AMBR towards the MME. The MME may create S1-AP: EPS bearer setup context request message for the EPS bearer of the mission critical video comprising EPS bearer identity, EPS bearer QoS, UE-AMBR, and session management request message which is comprising PTI, EPS bearer QoS, TFT, APN-AMBR, and EPS bearer Identity. The MME may send the S1-AP: EPS bearer setup context request message towards the eNodeB. 
     The eNodeB may map the EPS bearer setup request for mission video to the radio bearer setup. The eNodeB may send radio bearer QoS, session management request message, and EPD radio bearer towards the MCVideo UE. The MCVideo UE may store QoS for the mission critical video, radio priority, packet flow ID from the session management request message and APN-AMBR. The MCVideo UE may provide the EPS bearer QoS for mission critical video to the MCVideo application. The MVVideo UE may acknowledge the reception of the bearer setup request towards the MME via eNodeB. The MCVideo UE may create a NAS: uplink NAS transport comprising a session management response comprising an EPS bearer identity and send it toward the MME via eNodeB. The MME may send a GTP: session management response message comprising EPS bearer ID and the MCVideo user location towards the PDN-GW. The PDN-GW may send a provision acknowledge message towards the PCRF to indicate that the new QoS for the mission critical video could have been enforced and it may inform the PCRF about user location information and the MCVideo UE time zone. The PCRF will inform the AF about the finalization of the IP-CAN session modification. A mission critical media session may now be established between by MC UE  1  for the exchange of video/audio packets. 
     Mission critical session modification and IMS session modification. In an example embodiment, an MC UE  1  may register as to the IMS network and thereafter may setup an MCVideo session with MC UE  2 . At the time of session setup with MC UE  2 , MC UE  1  may employ IMS communication service indicator (ICSI) and/or IMS application reference indicator (IARI) registered to MCVideo in Contact header field, P-Preferred-Service header field, and/or Accept-Contact header field to indicate its capabilities for MCVideo. Due to different circumstances such as geographical circumstances, the radio coverage for the MC UE  1  may become weak and result in video/audio packets dropped to the point that the MCVideo session gets destroyed. In order to avoid loss of the MC session, MC UE  1  may renegotiate the MCVideo session with MC UE  2  in the sense to exclude for instance the video part of the session media of the MCVideo, but maintain the audio part of the media, in case the audio part is of more importance. If the video part is of more importance, then MC UE  1  may renegotiate to maintain the video media but to exclude the audio part. MC UE  1  may also renegotiate new bandwidth and/or resolution for the audio and/or video in order to maintain the MC session. 
     The modification of the bandwidth and/or resolution may already be allowed by the current existing media codecs for the MCVideo/MCPTT/MCAudio session. Thus upon the coverage deterioration and decrease of signal to noise ratio, the codecs may adapt to the new environment and may employ e.g. less number of pixels and/or frame per second for video and may employ e.g. less bandwidth for the audio. Due to the type of mission critical media, the audio and the video parts of this media may employ the same bearer while being multiplexed. The mission critical UE may therefore choose to modify and/or remove the audio and/or video part of the mission critical media employing the same bearer for the audio and/or video. 
       FIG.  25    is a block diagram illustrating an example MC UE engaged in a mission critical session with MC UE 2 , where the mission critical media may have already been negotiated, the radio coverage may be deteriorated, and the employed codecs for the mission critical communication may adapt to the new signal to noise radio and may as the result transmit/receive less data for the air to other MC UE with the MC session. The MC media may also be modified by renegotiation of the capabilities of the MC media by employing session description protocol (SDP) in the SIP message request which may have been transmitted by MC UE  1  towards MC UE  2 . The SDP may list the modification as new bandwidth and/or resolution. It may also remove/replace/add/modify the MC media which may have been employed for the communication between MC UE  1  and MC UE  2 . Thus upon the coverage deterioration and decrease of signal to noise ratio, MC UE  1  may send a SIP request message with SDP which list the new MC media, towards MC UE  2  in order to re-negotiate the MC media for the existing radio coverage. Furthermore, at the time of the MC session modification, MC UE  1  may also choose to employ new feature tags defining modified capabilities and ICSI and/or IARI in Contact header field, P-Preferred-Service header field, and/or Accept-Contact header field to indicate the modified capabilities for the MC session. 
       FIG.  26 A  is an example table of a list of ICSIs and/or IARIs which may be employed at various measured signal-to-noise ratios, corresponding to different combinations of the media.  FIG.  26 B  is an example table of a list of ICSIs and/or IARIs corresponding to different quality of service (QoS) values and/or QoS class identifier (QIC) values due to the different level of measured signal to noise ratio. Upon reception of these ICSI and/or IARI, an application server may realize the request for the mission critical session and may thus take appropriate action accordingly. 
       FIG.  27    is a flow diagram of an example modified mission critical media session as per an aspect of an embodiment. An MC UE  1  may send a session re-invitation or update towards MC UE  2  via IMS network and the MC AS, adding new ICSI and/or new IARI registered to MCVideo/MCPTT/MCAudio as feature tag to Contact header field, P-Preferred-Service header field, and/or Accept-Contact header field to indicate modified capabilities due to new radio coverage. MC UE  1  may send a session re-invitation or update towards MC UE  2  via IMS network and the MC AS, listing an addition/modification of the media and its properties in the SDP. MC UE  2  may accept the invitation by sending an “OK” towards MC UE  1  via IMS network and the MC AS. MC UE  1  may acknowledge the acceptance by sending an “ACK” towards MC UE  2  via IMS network and the MC AS. The modified mission critical media session may now be established between the MC UE  1  and MC UE  2 . Within that MC media session, the video and/or audio packets may be exchanged between the MC UEs. 
     IP CAN session modification. The application function (AF) of the MC session may be triggered by, for example an MC UE  1 , to modify and/or to downgrade and/or to deactivate the dedicated EPS bearer for the mission critical video and/or to modify and/or to downgrade and/or to deactivate the dedicated EPS bearer for mission critical audio due to, for example, deterioration of the network coverage. The triggering mechanism may be due to the new ICSI and/or IARI in Contact header field, P-Preferred-Service header field, and/or Accept-Contact header field of a SIP request message to indicate the modified capabilities for the MC session. The triggering mechanism may also be due to the modification of the listed MC media and their properties in the SDP. The MC AF may simply realize the requested changes by the SIP header and/or SDP information. Upon the MC AF approval, QoS parameters of the dedicated EPS bearer for the mission critical video/audio session may be relaxed (requiring a less strict QoS requirement) with a new or existing QCI level for non-GBR resource type. This may result in that the recipients, MC UE  2  may receive lower quality of the video images and/or lower quality of audio transmitted by the MC UE  1 . If the network coverage improves, MC UE  1  may trigger the AF to re-establish the better quality MC video and/or MC audio by employing new sets of ICSI and/or IARI in Contact header field, P-Preferred-Service header field, and/or Accept-Contact header field of a SIP request message to indicate the modified capabilities for the MC session. MC UE  1  may also employ new set of media and new properties for them in the SDP of the SIP request message to trigger AF to re-established the MC session with high media quality. 
     The EPS bearer resource reassignment may be triggered by the MC UE  1  when the network coverage deteriorates. This may also be triggered by the MC UE  1  by sending ESM message bearer resource modification request toward the network to trigger ESM message modify EPS bearer context request by the network toward the MC UE  1 . This may result in that the recipients of the MC UE  1  call may send/receive lower quality of the video image packets and/or audio packets. If the network coverage enhances, MC UE  1  may obtain a better signal to noise ration and may request for improvement of the dedicated EPS bearer for the mission critical session. A similar procedure may be implemented o improve the QoS. Other recipients in the MC session call such as MC UE  2  may receive better quality of the video/audio transmitted by that MC UE  1 . 
     Example embodiments may be applicable to other services in addition to mission critical services. For example, example embodiments may be implemented in a video conference call service, video call service, and non-emergency audio and/or video calls (such as a conference call). In an example, other services may be implemented. For example, the above process may be implemented for a Video call, video call AF, and/or video call UE. 
       FIG.  28    is a flow diagram of an example network initiated IP CAN session modification as per an aspect of an embodiment. In one example embodiment i.e. network initiated IP CAN session modification, shown in  FIG.  28   , there may be two dedicated bearers for mission critical video and mission critical audio of the user plan of the MCVideo application. There may be a default bearer for signaling of the MCVideo application. The AF may be triggered by, for example, the MCVideo user to downgrade or upgrade the priority for the dedicated EPS bearer and thereby the packet flow for the mission critical video due to, for example, deterioration or improvement of the network coverage. Due to the nature of the MCVideo session, there may be an impact on the dedicated bearer for the audio part or the dedicated bearer for the video part of the session. Although  FIG.  28   , shows that the dedicated bearer for the video has changed QCI number and the dedicated bearer for the audio maintain its QCI number, it needs to be pointed out that  FIG.  28    is an example and the QCI values are not limited to this illustration. 
     According to an embodiment, MC UE  1  may choose to modify the dedicated bearer due to loss or gain of network coverage by measuring signal-to-noise ratio by employing IMS communication service indicator (ICSI) and/or IMS application reference indicator (IARI) registered to MCVideo in Contact header field, P-Preferred-Service header field, and/or Accept-Contact header field to indicate its new capabilities due to the change of the network coverage for the MCVideo session. Instead of/with ICSI and/or IARI, MC UE  1  may choose to employ SDP to list a modification for the media lines and their properties which are already setup for the MC session. This may downgrade or upgrade the priority of the dedicated EPS bearer for the mission critical video and/or mission critical audio of the MCVideo application. That may trigger as an indication to the AF which may reside in the P-CSCF considering MCVideo is an IMS application, for EPS bearer modification request. The AF may initiate the IP-CAN session modification procedure by conveying information for the network coverage modification to the PCRF. The AF may use a new dedicated MCVideo application attribute value pairs (AVP) together with a priority modification AVP in the diameter AA-request transmitted by the MCVideo AF towards the PCRF. The PCRF may receive the MCVideo AVP together with the priority modification AVP and may attempt to modify the IP-CAN to enable that MCVideo service receives the assigned priorities affected by the modification of the network coverage. 
     According to an embodiment, the AF and PCRF may implement a signaling using a new AVP to implement the communication between the AF and the PCRF regarding the assigned priorities of MCVideo service. The signaling may list a number of priority levels triggered by the network coverage and/or by other means, for example, the MCVideo user may modify the priorities due to other needs than network coverage change, such as upgrade to an emergency MCVideo call or downgrade to a regular MCVideo call. The MCVideo UE and the PCRF may use those levels to ensure the IP-CAN is accordingly assigned to that MCVideo service. Therefore, an authorized Resource-Priority header field comprising an appropriate namespace and priority value in a SIP message if MCVideo service is an IMS service. In one example embodiment, the AF and AF functionalities may exist in a P-CSCF while in another example embodiment, the AF and AF functionalities may exist in an MCVideo application server (AS). 
     The PCRF may send a DIAMETER: update bearer request comprising a PCC decision provision (QoS policy) which may request the MCVideo user&#39;s location information and MCVideo UE time zone toward the PDN-GW. The PDN-GW may use the policy to adjust the EPS bearer QoS and may use to generate the traffic flow template (TFT). The PDN-GW may create GTP: update bearer request message comprising procedure transaction identifier (PTI) for GTP: update bearer request, EPS bearer identity, EPS bearer QoS, APN-AMBR, and TFT. The PDN-GW may send the GTP: update bearer request toward the S-GW. The S-GW may send GTP: update bearer request message comprising PTI, EPS bearer identity, EPS bearer QoS, TFT, and APN-AMBR towards the MME. If the APN-AMBR has changed, the MME may update the UE-AMBR is appropriate. The MME may create S1-AP: modify EPS bearer context request message for the EPS bearer of the mission critical video comprising EPS bearer identity, EPS bearer QoS, UE-AMBR, and session management request message which is comprising PTI, EPS bearer QoS, TFT, APN-AMBR, and EPS bearer Identity. The MME may send the S1-AP: modify EPS bearer context request message towards the eNodeB. The eNodeB may map the modified EPS bearer QoS for mission critical video/audio to the radio bearer QoS. The eNodeB may send radio bearer QoS, session management request message, and EPD radio bearer towards the MCVideo UE. The MCVideo UE may store new QoS for the mission critical video/audio, radio priority, packet flow ID from the session management request message and modified APN-AMBR. The MCVideo UE may provide the new EPS bearer QoS for mission critical video/audio to the MCVideo application. The MVVideo UE may acknowledge the reception of the bearer modification request towards the MME via eNodeB. The MCVideo UE may create a NAS: uplink NAS transport comprising session management response which is comprising EPS bearer identity and send it toward the MME via eNodeB. The MME may send GTP: session management response message comprising EPS bearer ID and the MCVideo user location towards the PDN-GW. The PDN-GW may send a provision acknowledge message towards PCRF to indicate that the new QoS for the mission critical video/audio could have been enforced and it may inform the PCRF about user location information and the MCVideo UE time zone. The PCRF may inform the AF about the finalization of the IP-CAN session modification. 
       FIG.  29    is a flow diagram of an example MC UE  1  initiated IP CAN session modification as per an aspect of an embodiment. In an example embodiment, for example, an MC UE  1  initiated IP CAN session modification, shown in  FIG.  29   , shows at the time of change of the network coverage, the MCVideo UE may modify the priority of the dedicated EPS bearer corresponding from QCI XY to QCI AB for the mission critical video by requesting the network to modify the EPS bearer context. The new QCI may have non GBR or GBR. However, the new EPS bearer may offer either lower bitrate, higher error loss rate, and higher delay budget for the uplink to release EPS resources if the network coverage is deteriorated or MCVideo UE stopped sending audio packets, or higher bitrate, lower error loss rate, and lower delay budget for uplink to gain EPS resources if the network coverage is improved or the MCVideo UE started sending audio packets. Due to the nature of the MCVideo session, an impact may be either on the dedicated bearer for the audio part or the dedicated bearer for the video part of the session. Although  FIG.  29   , shows that the dedicated bearer for the video has changed QCI number and the dedicated bearer for the audio maintain its QCI number, it needs to be pointed out that  FIG.  29    is an example and the QCI values are not limited to this illustration. 
     The MCVideo UE may send a NAS: bearer resource modification request message comprising linked bearer identity (LBI), PTI, EPS bearer ID, QoS with QCI AB, and traffic aggregate description (TAD) towards the MME. The TAD may comprise the existing packet filter and bitrate requirement for EPS bearer to modify the bitrate. The MME may send GTP: bearer resource command message comprising IMSI, LBI, PTI, EPS bearer ID, new QoS, and TAD towards the S-GW. The S-GW may send GTP: bearer request command message comprising IMSI, LBI, PTI, EPS bearer ID, new QoS, and TAD towards the same PDN-GW as identified by the LBI. The PDN-GW may interact with the PCRF to trigger appropriate PCC decision with the MCVideo user&#39;s subscription information. In order to make this decision, the PDN-GW may provide the PCRF the content of TAD regarding the filter packet and the modified GBR requirement for the EPS bearer. The PCRF may request for the MCVideo user&#39;s location information and the MCVideo UE time zone. The PDN-GW may send the GTP: update bearer request toward the S-GW. The S-GW may send GTP: update bearer request message comprising PTI, EPS bearer identity, EPS bearer QoS, TFT, and APN-AMBR towards the MME. If the APN-AMBR has changed, the MME may update the UE-AMBR. The MME may create an S1-AP: modify EPS bearer context message comprising EPS bearer identity, EPS bearer QoS, UE-AMBR, and session management request message which is comprising PTI, EPS bearer QoS, TFT, APN-AMBR, and EPS bearer Identity. The MME may send the S1-AP: modify EPS bearer context request message towards the eNodeB. The eNodeB may map the modified EPS bearer QoS to the radio bearer QoS and it may send radio bearer QoS, session management request message, and EPD radio bearer towards the MCVideo UE. The MCVideo UE may store the new QoS, radio priority, packet flow ID from the session management request message and modified APN-AMBR. The UE may provide the new EPS bearer QoS to the MCVideo application. The MCVideo UE may acknowledge the reception of the bearer modification message towards the MME via eNodeB. The MCVideo UE may create a NAS: uplink NAS transport comprising session management response comprising EPS bearer identity and may send it toward the MME via eNodeB. The MME may send GTP: session management response message may comprise an EPS bearer ID and the MCVideo user location towards the PDN-GW. The PDN-GW may send a provision acknowledge message towards PCRF to indicate that the new modified QoS could have been enforced and it may inform the PCRF about user location information and the MCVideo UE time zone. 
     Example embodiments may be applicable to other services in addition to mission critical services. For example, example embodiments may be implemented in a video conference call service, video call service, and non-emergency audio and/or video calls (such as a conference call). In an example, other services may be implemented. For example, the above process may be implemented for a Video call, video call AF, and/or video call UE. 
     In this specification, “a” and “an” and similar phrases are to be interpreted as “at least one” and “one or more.” In this specification, the term “may” is to be interpreted as “may, for example.” In other words, the term “may” is indicative that the phrase following the term “may” is an example of one of a multitude of suitable possibilities that may, or may not, be employed to one or more of the various embodiments. If A and B are sets and every element of A is also an element of B, A is called a subset of B. In this specification, only non-empty sets and subsets are considered. For example, possible subsets of B={cell 1 , cell 2 } are: {cell 1 }, { cell 2 }, and { cell 1 , cell 2 }. 
     In this specification, parameters (Information elements: IEs) may comprise one or more objects, and each of those objects may comprise one or more other objects. For example, if parameter (IE) N comprises parameter (IE) M, and parameter (IE) M comprises parameter (IE) K, and parameter (IE) K comprises parameter (information element) J, then, for example, N comprises K, and N comprises J. In an example embodiment, when one or more messages comprise a plurality of parameters, it implies that a parameter in the plurality of parameters is in at least one of the one or more messages, but does not have to be in each of the one or more messages. 
     Many of the elements described in the disclosed embodiments may be implemented as modules. A module is defined here as an isolatable element that performs a defined function and has a defined interface to other elements. The modules described in this disclosure may be implemented in hardware, software in combination with hardware, firmware, wetware (i.e hardware with a biological element) or a combination thereof, all of which are behaviorally equivalent. For example, modules may be implemented as a software routine written in a computer language configured to be executed by a hardware machine (such as C, C++, Fortran, Java, Basic, Matlab or the like) or a modeling/simulation program such as Simulink, Stateflow, GNU Octave, or LabVIEWMathScript. Additionally, it may be possible to implement modules using physical hardware that incorporates discrete or programmable analog, digital and/or quantum hardware. Examples of programmable hardware comprise: computers, microcontrollers, microprocessors, application-specific integrated circuits (ASICs); field programmable gate arrays (FPGAs); and complex programmable logic devices (CPLDs). Computers, microcontrollers and microprocessors are programmed using languages such as assembly, C, C++ or the like. FPGAs, ASICs and CPLDs are often programmed using hardware description languages (HDL) such as VHSIC hardware description language (VHDL) or Verilog that configure connections between internal hardware modules with lesser functionality on a programmable device. Finally, it needs to be emphasized that the above mentioned technologies are often used in combination to achieve the result of a functional module. 
     The disclosure of this patent document incorporates material which is subject to copyright protection. The copyright owner has no objection to the facsimile reproduction by anyone of the patent document or the patent disclosure, as it appears in the Patent and Trademark Office patent file or records, for the limited purposes required by law, but otherwise reserves all copyright rights whatsoever. 
     While various embodiments have been described above, it should be understood that they have been presented by way of example, and not limitation. It will be apparent to persons skilled in the relevant art(s) that various changes in form and detail can be made therein without departing from the spirit and scope. In fact, after reading the above description, it will be apparent to one skilled in the relevant art(s) how to implement alternative embodiments. Thus, the present embodiments should not be limited by any of the above described exemplary embodiments. In particular, it should be noted that, for example purposes, the above explanation has focused on mission critical services such as mission critical push-to-talk services employing media types such as audio services, video services and media services. However, one skilled in the art will recognize that embodiments of the invention may also be implemented in a system comprising other types of services such as, for example, data services, augmented reality services, data fusion services, combinations thereof, and/or the like. 
     In addition, it should be understood that any figures which highlight the functionality and advantages, are presented for example purposes only. The disclosed architecture is sufficiently flexible and configurable, such that it may be utilized in ways other than that shown. For example, the actions listed in any flowchart may be re-ordered or only optionally used in some embodiments. 
     Further, the purpose of the Abstract of the Disclosure is to enable the U.S. Patent and Trademark Office and the public generally, and especially the scientists, engineers and practitioners in the art who are not familiar with patent or legal terms or phraseology, to determine quickly from a cursory inspection the nature and essence of the technical disclosure of the application. The Abstract of the Disclosure is not intended to be limiting as to the scope in any way. 
     Finally, it is the applicant&#39;s intent that only claims that include the express language “means for” or “step for” be interpreted under 35 U.S.C. 112. Claims that do not expressly include the phrase “means for” or “step for” are not to be interpreted under 35 U.S.C. 112.