| 摘要 |
PURPOSE:To attain satisfactory communication without fault in intermodulation and to contrive effective utilization of frequency by dividing a radio channel into plural groups, arranging divided radio channels in a plane or a stereoscopic zone so as to improve the channel rate without an intermodulation fault. CONSTITUTION:A radio channel is divided into plural groups, the plural divided radio channel groups are allocated to plural service zones arranged in 2-dimension or in 3-dimension so that same kinds of service zones are not adjacent to each other to set a radio channel. That is, when a portable telephone system is installed in a building, the three-channel system is installed to each floor in stationary radio stations (FRS-1)-(FRS-4) and the service area is as shown in dotted lines. Each floor is interrupted to some degree in terms of a radio wave by a floor plate and a radio wave from other floors is hardly intruded. Thus, pleasant communication without intermodulation is attained and a channel number without disturbance of intermodulation is taken much, then the effective utilization of frequency is attained. |
