Method, mobile exchange, and subscriber station in a mobile radio system for establishing a high-priority call

A mobile radio system for establishing a high-priority individual call or group call to at least one subscriber in a mobile radio system participating in a first group call conducted on a given channel, the mobile radio system comprising:

• a mobile exchange comprising:
• a switching matrix;
• an interface unit;
• a controller;
• a memory for storing subscriber identifiers and group call identifiers;
• and
• sending means for sending a release message provided with an identifier of the subscriber participating in the first group call to whom it is desired to establish a high-priority individual call or high-priority group call and/or an identifier of a high-priority individual call or high-priority group call to be established, to all subscribers engaged in the first group call;
• and
• subscriber equipment of subscribers engaged in the first group call being arranged to receive said release message, wherein:
• said subscriber equipment of said subscriber to whom it is desired to establish a high-priority individual call or high-priority group call being arranged to detect on the basis of said identifier included in the release message that the release message is intended for said subscriber;
• said subscriber equipment of said subscriber being arranged in response to said detection to terminate the engagement of said subscriber in the group call;
• and
• said subscriber equipment of said subscriber being arranged to join said high-priority call on the basis of the high-priority call identifier received.

A subscriber station for a mobile radio system, comprising:

• a memory for storing identifiers of group calls allowed for the subscriber station;
• a transceiver;
• a handset;
• a control unit for controlling the operation of the subscriber station in response to commands from the handset and a system controller of the mobile radio system;
• receiving means for receiving a release message containing an identifier of high-priority individual call or high-priority group call to be established, for comparing the identifier included in the release message, with the identifier of the subscriber station and/or with a group call identifier stored in the memory of the subscriber station as an identifier of an allowed group call, and for detecting on the basis of said identifier included in the release message that the release message is intended for said subscriber;
• and
• terminating means responsive to such comparison for terminating the engagement of the subscriber in the first group call and for releasing the subscriber station from the first group call and for transferring the subscriber station to a high-priority individual call or high-priority group call to be established.