Nokia Telecommunications Oy

Hannu Toyryla

Rauno Suikkola

Anna Sillanpaa

Mika Heiskari

Mika Lehmusto

Tapio Paavonen

Call establishment in a mobile communication system

A method for maintaining a group call in a mobile radio system, and a mobile station in a mobile radio system, wherein the geographical area covered by the system is divided into radio cells. Each radio cell includes a base station. A group call is established between the mobile stations belonging to a group call group and residing within the areas of the radio cells forming a limited group call area. In order that the mobile station, upon changing radio cells, is able to select the base station within the area of which the group call is in progress, the respective base stations send one or a plurality of group call maintenance messages to the mobile stations involved in the group call. The group call maintenance message contains information concerning the base stations located within the areas of the radio cells forming the group call area, and the group call group identity.

Method for maintaining a group call

Establishment of a call in a mobile communication system

Method and apparatus for prioritizing plural requests by subscribers for

Method of informing a subscriber in a radio telephone system of

The invention relates to a method for setting up a group call in a cellular radio system. The method comprises allocating a traffic channel to the group call and transmitting a group call paging message containing a traffic channel indication via each base station (BS1) whose radio cell (C1) resides in a predetermined operation area of the called group to the mobile radio stations (MS1-MS5) of the group. In order to ensure that all the mobile stations of the group roaming in the area participate in the group call, an additional group call paging message is transmitted via the base stations (BS2) of radio cells (C2) adjacent to said predetermined operation area to mobile radios (MS4, MS5) of the group. The additional group call paging message contains an instruction to switch to the allocated traffic channel of the radio cell (C1) residing in said operation area.

Method for setting up a group call in a cellular radio system

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Vantaa, Finland

Hannu Toyryla