Pre-rake diversity combining for TD-SCDMA base stations

The paper explores the possibility of applying pre-rake technique in TD-SCDMA systems to improve the communication quality of the systems. The channel estimation approach for pre-rake circuits is provided. This paper analyzes the performance of pre-rake techniques for TD-SCDMA systems, based on quarter phase-shift keying (QPSK) modulation. From the simulation results we find that QPSK has the advantage of stability over BPSK while both of them have the same averaged bit error rate (BER). This advantage, together with the superiority over rake receiver of moving the circuits from the mobile unit (MU) to the base station (BS), makes the pre-rake technique useful in TD-SCDMA systems.