FIELD: multiple access systems with code channel division. SUBSTANCE: time of execution and direction of switching in procedure of tight channel switching by base- station controller are determined for mobile station moving between two transceiver stations having different frequency distribution. . Servicing area of multiple access code-division system is divided into separate locations; each location has one or more sectors (sub-locations). The latter are, essentially, either general-frequency sub-locations or cutoff- frequency ones. General-frequency sub-locations are those using all general frequencies of adjacent sub-locations. Cutoff-frequency sub- locations are accordingly determined as those using not all general frequencies of adjacent locations. According to invention method involves following procedures: base-station controller receives message from mobile station about change in pilot-signal level; this message includes set of pilot-signals each being distinguished by pilot-signal level; after base-station controller has received this message all sub-locations with which mobile station can communicate at the time are checked to make sure that all of them are cutoff-frequency sub-locations; if it is found that at least one of them is other than cutoff-frequency sub- location, communication channel switching of general type is executed; if all sub-locations are found to be cutoff-frequency sub-locations, base- station controller periodically requests pilot-signal level change message from all sub-locations communicating with mobile station at present; message transmitted from mobile station in response to controller- initiated message request is analyzed to make sure that level of pilot- signals received from all sub-locations is not lower than preset definite power level T DOWN ; then timer preset to definite time T DOWN is invoked in case level of mentioned pilot-signals received from all sub- locations is below preset power level T DOWN; if timer completes reading without interruption within T DOWN interval, command is sent to mobile station for executing tight switching of communication channel inside location to general frequency serviced by all base transceiver stations. EFFECT: provision for tight frequency-to-frequency switching of communication channel. 14 cl, 4 dwg
