methods of operating a mission-critical push-to-talk node and operation of a eu, mission-critical push-to-talk node, and user equipment.

摘要

A mission critical push-to-talk (mcptt) node (410, 510, 600, 800) is connected to a group of user equipment (405, 505, 700, 900) served by the mcptt node. mcptt node generates a multimedia broadcasting service (mbms) (mscck) subchannel control key (s305), sends the first messages to the unicast ues, where the first messages include the generated mscck (s310), generates at least one mbms subchannel control message (s315), applies integrity protection and / or confidentiality protection to at least one mbms subchannel control message with mscck (s320), and sends at least one control message multicast MBMS subchannel (s325).