Method and system for notifying state of members of mission critical service (MCX) groups

1. A method for notifying a state of a plurality of members of one or more mission critical service, MCX, groups to an MCX user equipment, UE, in a mission critical, MC, communication system, the method comprising:

receiving, by an MCX server, a session initiation protocol,(SIP), subscribe request message for a conference event from the MCX UE;

identifying, by the MCX server, a plurality of members of the one or more MCX groups in response to receiving the SIP subscribe request message from the MCX UE;

identifying, by the MCX server, the state of each member of the one or more groups;

categorizing, by the MCX server, the plurality of members of the one or more groups based on the identified state of each member; and

notifying, by the MCX server, the state of the plurality of members of the one or more groups to the MCX UE based on the categorization.

2. The method of claim 1 , wherein the MCX server notifies the state of the plurality of members of the one or more groups to the MCX UE over a signaling control plane.

3. The method of claim 1 , wherein the SIP subscribe request message is appended in a SIP invite request message as a SIP header by the MCX UE.

4. The method of claim 3 , wherein the MCX server notifies the state of the plurality of members of the one or more groups to the MCX UE in response to receiving the SIP invite request message with the SIP subscribe request message as the SIP header.

5. The method of claim 1 , wherein the MCX server notifies the state of the plurality of members of the one or more groups to the MCX UE over an enhanced multimedia broadcast multicast service, eMBMS, channel.

6. The method of claim 1 , wherein the method further comprises:

determining, by the MCX server, whether a floor is granted to the MCX UE; and

dynamically notifying, by the MCX server, an updated state of the plurality of members of the one or more groups to the MCX UE in response to determining that the floor is granted to the MCX UE.

7. The method of claim 1 , wherein the MCX server identifies the plurality of members of the one or more MCX groups by assigning indexes for the plurality of members, wherein the indexes are associated with the plurality of members in the conference event.

8. The method of claim 1 , wherein the MCX server notifies the state of the members of the one or more MCX groups in a pre-defined location range based on location information of the members.

9. The method of claim 1 , wherein the MCX server receives a SIP register request message for a register event from the MCX UE, wherein the MCX server notifies a registration state of the MCX UE.

10. The method of claim 9 , wherein a SIP subscribe request message for the register event is appended in the SIP register request message during a MCX service registration by the MCX UE.

11. The method of claim 9 , wherein the MCX server notifies the state of the registration to the MCX UE over a signaling control plane.

12. A mission critical service, MCX, server for notifying a state of a plurality of members of one or more (MCX) groups to an MCX UE in a mission critical, MC, communication system, the MCX server comprising:

a communicator configured to transmit or to receive signal; and

a controller configured to:

receive a session initiation protocol,(SIP), subscribe request message for conference event from the MCX UE;

identify a plurality of members of the one or more MCX groups in response to receiving the SIP subscribe request message from the MCX UE;

identify the state of each member of the one or more groups;

categorize the plurality of members of the one or more groups based on the identified state of each member; and

notify the state of the plurality of members of the one or more groups to the MCX UE based on the categorization.

13. The MCX server of claim 12 , wherein the MCX server notifies the state of the plurality of members of the one or more groups to the MCX UE over a signaling control plane.

14. The MCX server of claim 12 , wherein the SIP subscribe request message is appended in a SIP invite request message as a SIP header by the MCX UE.

15. The MCX server of claim 14 , wherein the MCX server notifies the state of the plurality of members of the one or more groups to the MCX UE in response to receiving the SIP invite request message with the SIP subscribe request message as the SIP header.

16. The MCX server of claim 12 , wherein the MCX server notifies the state of the plurality of members of the one or more groups to the MCX UE over an enhanced multimedia broadcast multicast service, eMBMS, channel.

17. The MCX server of claim 12 , wherein the controller is further configured to:

determine whether a floor is granted to the MCX UE; and

dynamically notify an updated state of the plurality of members of the one or more groups to the MCX UE in response to determining that the floor is granted to the MCX UE.

18. The MCX server of claim 12 , wherein the MCX server identifies the plurality of members of the one or more MCX groups by assigning indexes for the plurality of members,

wherein the indexes are associated with the plurality of members in the conference event, and

wherein the MCX server notifies the state of the members of the one or more MCX groups in a pre-defined location range based on location information of the members.

19. The MCX server of claim 12 , wherein the MCX server receives a SIP register request message for a register event from the MCX UE, wherein the MCX server notifies a registration state of the MCX UE.

20. The MCX server of claim 19 , wherein a SIP subscribe request message for the register event is appended in the SIP register request message during a MCX service registration by the MCX UE, and

wherein the MCX server notifies the state of the registration to the MCX UE over a signaling control plane.