Mobile radio transmission system and a mobile station for use in the system.

摘要

A private mobile radio transmission system comprising a plurality of geographically spaced base stations (BS1-7) defining a plurality of overlapping service areas (SA1-7). The base stations are coupled for example by land-line communication links (CL1-7) to a system controller (SC). Mobile stations (MS1-3) equipped with simplex two-way radios are free to roam through the service areas. In order to be able to make a call with or via a base station it is necessary for the mobile station to be registered with the base station concerned. Details of the registration are stored by the mobile station concerned and the base station. In order to optimise on the usage of radio channels, details of a home base station are preprogrammed into each mobile station and when the mobile station wishes to register with a base station, it is instructed to try to register firstly with its own base station, on the basis that the majority of calls will be to and from the home service area and will require only one pair of frequencies, secondly with a base station of any other service area in its region, and thirdly with a base station of a service area in any other region. When registered with a service area other than its home one, the mobile station checks regularly to see if it is possible to register with its home service area.