Establishing a group call in a mobile radio system

• US 5,852,781 A
• Filed: 07/10/1996
• Issued: 12/22/1998
• Est. Priority Date: 11/11/1994
• Status: Expired due to Fees

• Current Assignee: EADS Secure Networks
• Original Assignee: Nokia Telecommunications Oy (Nokia Corporation)
• Inventors: Ahvenainen, Jouko
• Primary Examiner(s): LE, THANH C
• Application Number:
  US08/676,176
• Time in Patent Office: 895 Days
• Field of Search: 455/507, 455/509, 455/510, 455/512, 455/514, 455/517, 455/518, 455/519, 455/520, 455/521, 455/426
• US Class Current: 455/509
• CPC Class Codes: H04W 84/08 Trunked mobile radio systems

Abstract

A method and mobile radio system for establishing a group call extending to service areas of several exchanges in a mobile radio system which includes at least a first exchange and a second exchange, telecommunication media for establishing communication connections between at least the first exchange and the second exchange, and a plurality of mobile stations communicating via the exchanges. The method includes selecting a second exchange to which the group call is routed from the first exchange. To save telecommunication resources in a mobile radio system, checking, before routing the call to the second exchange, whether a telecommunication medium has been previously allocated on the connection from the first to the second exchange for the group call to be established, and, if so, routing the group call to be established from the first to the second exchange without allocating a new telecommunication medium to that connection.

Claims

1. A method for establishing a group call extending into the respective service areas of a plurality of exchanges in a mobile radio system which includes at least a first and a second exchange, a telecommunication transmission medium between said first and second exchanges, and a plurality of mobile stations communicating via said exchanges, said method comprising the steps of:

starting to establish a group call involving a plurality of said mobile stations, located within the respective service areas of a plurality of said exchanges, including said first and the second exchanges,

selecting said second exchange to be one to which the group call is to be routed from said first exchange,

maintaining a database which indicates, specifically for each group call, the telecommunication transmission medium that is allocated for that group call on each connection between respective ones of said exchanges,

checking said database before routing said group call starting to be established from said first to said second exchange, to see whether a telecommunication transmission medium has been previously allocated on the respective said connection from said first to said second exchange for said group call starting to be established,

routing said group call starting to be established from said first to said second exchange using a respective previously allocated telecommunication medium, without allocating a new telecommunication transmission medium to the respective said connection, if a telecommunication transmission medium has been previously allocated on the respective said connection for said group call starting to be established, as determined from said checking.

2. The method according to claim 1, further comprising the steps of:

if said database, when said checking is performed, does not indicate that a telecommunication transmission medium has been allocated for said group call starting to be established on the respective said connection, allocating a telecommunication transmission medium for said group call about to be established on the respective said connection between said first and second exchanges,

marking allocation of the respective said telecommunication transmission medium in said database, and

routing said group call starting to be established, from said first to said second exchange with the respective said telecommunication transmission medium allocated in said allocating step.

3. A mobile radio system for establishing a group call extending into the respective service areas of a plurality of exchanges, comprising:

a plurality of exchanges, including a first and a second exchange each having a respective source area,

a plurality of mobile stations communicating via said exchanges, including via said first and second exchanges,

a telecommunication transmission medium for establishing a group call between said first and second exchanges,

a database which indicates, for each group call, the telecommunication transmission medium that is allocated for the respective said group call on each connection from said first to said second exchange,

checking means for checking whether a telecommunication transmission medium has been previously allocated on the respective said connection from said first to said second exchange for said group call to be established,

said checking means being arranged to;

(a) allocate a telecommunication transmission medium on said connection between said first and said second exchange for said group call to be established, if said database indicates that no telecommunication transmission medium has been previously allocated for said group call on said connection between said first and said second exchange, and

(b) route said group call to be established from the first to the second exchange respectively via said allocated or previously allocated telecommunication transmission medium.

4. A mobile radio system for establishing a group call extending into the respective service areas of a plurality of exchanges, comprising:

a plurality of exchanges, including a first and a second exchange each having a respective source area,

a plurality of mobile stations communicating via said exchanges, including via said first and second exchanges,

a telecommunication transmission medium for establishing a group call between said first and second exchanges,

a database which indicates, for each group call, the telecommunication transmission medium that is allocated for the respective said group call on each connection from said first to said second exchange,

checking means for checking whether a telecommunication transmission medium has been previously allocated on the respective said connection from said first to said second exchange for said group call to be established,

means for marking allocation of the telecommunication transmission medium between said first and said second exchange in said database, if said database, upon checking of said check means does not indicate that the telecommunication transmission medium has been previously allocated for said group call on said connection between said first and second exchanges.