| 摘要 |
A macrocellular cellular telephone system has cells (macrocells) CI and CII. All the cells CI broadcast a particular Location Area Identity (LAI), and all the cells CII broadcast a different LAI. Upon receipt of an LAI, a macrocellular mobile station (MS) responds and the network thus knows its whereabouts. Communication is thus established with that MS by broadcasting from all cells within the appropriate area I or II. The network is also capable of offering a more restricted service to subscribers to a microcellular system - for example, service in large cities or towns identified at A,B and C. Microcells in these areas transmit LAI's which differ from the LAI's transmitted by the cells available for macrocellular subscribers. By means (for example) of its lower power level, a microcellular subscriber MS can be distinguished from a macrocellular MS and can be denied service unless it is within an area A,B or C. <IMAGE> |
