Synchronization acquisition device for both preventing erroneous detection due to noise and reducing required storage capacity

Abstract

A synchronization acquisition device in a spread spectrum communication system is disclosed that can both reduce the required storage capacity and prevent erroneous detection caused by such factors as noise. In the first correlation value processing, the control circuit causes only the N highest-ranking values of correlation values obtained by a correlator to be stored in a timing-correlation value storage unit. In the second and subsequent calculations, the control circuit stores K×P +(1−K)×P as the new value if a timing corresponding to the obtained correlation value P has already been stored, and stores K×P as the new value if a corresponding timing is not stored but the obtained correlation value is greater than the N correlation value that is stored. Instead of storing correlation values of all timings of a fixed interval portion, only correlation values that are peak candidates and the associated timing information are stored, and as a result, the device allows a reduction in the required storage capacity. In addition, in slot averaging processing, the reordering of timings that are peak candidates is based only on actual correlation values and not on dummy value, and erroneous detection due to such factors as noise therefore can be reduced.