IMPROVEMENTS IN OR RELATING TO CDMA RECEIVERS AND CDMA COMMUNICATIONS SYSTEMS

摘要

A CDMA communications system comprises a primary station (PS) and at least one secondary station (SS). The at least one secondary station includes a receiver (Rx) for receiving CDMA signals transmitted on the downlink, the receiver comprising a plurality of Rake finger receivers (20<SUB>1</SUB> to 20<SUB>N</SUB> ) having inputs for receiving signals and outputs coupled to a combining stage (not shown) for combining their output signals constructively, a finger assignment stage (16) for assigning the finger receivers to respective received signals, a processing stage (38) for estimating the speed of the CDMA receiver from the signals received and for varying the time required to make a finger replacement decision in response to the estimated speed so that the time required decreases as the speed of the receiver increases and vice versa.