| 摘要 |
PURPOSE:To keep encryption even if a mobile set makes zone transfer during call, by storing the presence/absence of encryption information in channel switching memories provided with a radio line control station, corresponding to a mobile set. CONSTITUTION:When a mobile set M starts a call at a zone 1 and requests encryption, the encryption request signal is transmitted to a radio base station A. The station A transmits the use of encryption by the mobile set to a radio line control station D through intra-station line 4. The station D stores the information of presence of encryption of a memory for channel switching during a call. When the mobile set M transfers from the zone 1 to a zone i, the control for channel switching is made at the station D, a vacant channel is designated at a ratio base station I and the mobile set M switches the channel to a new channel. In this case, the station transmits the information to the station I when the mobile set M uses encryption. Thus, the mobile set M can keep encryption. |
