Abstract: A method for use in a mobile communication system for estimating the location of a target mobile station (MS) which includes receiving signals from the target MS (N) at a plurality of receivers (MS1, MS2, MS3) in different locations and calculating the location of the target MS (N) from information obtained from the received signals, wherein at least one of the receivers (MS1) is a searching MS and wherein the calculation of location is carried out by the searching MS (MS1). The method may involve the target MS and the searching MS or MSs communicating by a direct mode of operation (DMO) link. The searching MSs may conveniently have GPS attachments. A mobile station which may be used as the target MS or as a searching MS and a system incorporating the same is also disclosed.

Abstract: A communication system comprises a first plurality of remote stations (107, 109, 111) belonging to a first call group (119) having an associated first encryption key and a first encryption mode. A second plurality of remote stations (113, 115) belongs to a second call group (121) having an associated second encryption key and a second encryption mode. A group controller (117) forms a third call group (123) which comprises the first and the second call groups (119, 123) and which has an associated third encryption key. When communicating on the third, combined call group, the first plurality of remote stations (107, 109, 111) use the third encryption key and the first encryption mode whereas the second plurality of remote stations (113, 115) use the third encryption key and the second encryption mode.

Abstract: A method and apparatus of operation of a mobile communication system comprising at least one mobile station is disclosed. The method and apparatus comprise storing in a database information relating to coverage areas of a plurality of wireless networks and monitoring the mobile station for its location while the mobile station is connected to a serving network. The method and apparatus then require comparing the monitored location of the mobile station with the stored coverage area information to produce an alert signal in the mobile station which indicates to the mobile station that one of the wireless networks is nearby. The method and apparatus then initiate a procedure to handover connectivity from the serving network to a nearby network, wherein the serving network and the nearby network use routing address protocols which have a common internet protocol (IP) address routing portion.

Abstract: A method for use in a mobile communication system for estimating the location of a target mobile station (MS) which includes receiving signals from the target MS (N) at a plurality of receivers (MS1, MS2, MS3) in different locations and calculating the location of the target MS (N) from information obtained from the received signals, wherein at least one of the receivers (MS1) is a searching MS and wherein the calculation of location is carried out by the searching MS (MS1). The method may involve the target MS and the searching MS or MSs communicating by a direct mode of operation (DMO) link. The searching MSs may conveniently have GPS attachments. A mobile station which may be used as the target MS or as a searching MS and a system incorporating the same is also disclosed.