Mobile radio systems

The efficient operation of mobile systems having asynchronous transmission mode (ATM) networks require rapid changes in mobile affiliation. If such changes in affiliation were to require network switching the response times could be too long. An alternative technique is used whereby permanent virtual paths are set up across the ATM network between base stations within a defined area and the interface point of a fixed network. Within this area the virtual channel identifier (VCI) is given global significance and is used to designate the call. The ATM network may be replaced by a network of dedicated lines.