| 摘要 |
A CDMA cellular system does not require accurate synchronization between all base stations and is capable of distinguishing the base stations from each other without the need for a complex process. When two element codes are multiplied with shifted timing to generate a spreading code, different codes that do not agree with each other when cyclically shifted are generated for the respective base stations. Spreading codes of the base stations are distinguished even when the base stations are not kept in synchronism with each other. In the CDMA cellular system which uses such spreading codes, when frame synchronization is achieved using a perch channel spread by a spreading code that is common to all the base stations, a signal transmitted from one of the base stations is de-spread on the basis of a first element code which is of the same timing (phase) with respect to a frame in all the base stations. Since the de-spread signal is a signal produced by shifting a second element code with timing (phase) which differs from base station to base station, a spreading code that is being used can be identified by a correlated value calculating unit. <IMAGE> |
