Abstract: A service area expansion scheme for a mobile communication system, capable of efficiently connecting thinly populated areas (satellite zones) to a mobile communication network so as to expand the service area of the mobile communication system economically. In expanding the service area, remote base stations are set at thinly populated areas, while a remote mobile local switching station for connecting the remote base stations to the mobile communication network is provided. The remote base stations and the remote mobile local switching station are selectively connected through the public network by using the respective channel connection units for providing connections with the public network. The remote base stations and the remote mobile local switching station can be replaced by satellite base stations and a satellite mobile local switching station for connecting the satellite base stations to the mobile communication network.

Abstract: A transmission power control method in a mobile satellite communication system implementing accurate control of transmission power of a base station by obtaining an average received signal level at a mobile station at high accuracy. The mobile station measures an average received signal level Q.sub.k in a predetermined period (step SP2), and informs the base station of the average received signal level Q.sub.k and an actual measuring time T.sub.k (step SP3). The base station calculates a total measuring time t.sub.k which is the sum total of the actual measuring time T.sub.k (step SP16), a corrected average received signal level R.sub.k associated with the average received signal level during the total measuring time t.sub.k (step SP18), and a measuring error .DELTA.D.sub.k (step SP17), and controls the transmission power on the basis of these values (step SP21). Estimating the measuring error .DELTA.D.sub.k in the total measuring time t.sub.k longer than the individual actual measuring time T.sub.