Performance Study on Spectrum Spreading and Scrambling Code in TD-SCDMA

The working principle, implementation circuit and performance analysis of complex spectrum spreading and scrambling code in TD-SCDMA (TD) are discussed in this paper. Assuming 8 users and 3-path propagation channels or without multi-path fading environment, the performance comparison between TD and cdma2000 is studied in this paper. With three-level mode in base-band signal and small spreading factor for voice service, the performance of TD in both scenarios is worse. Moreover, in contrast to cdma2000 and WCDMA, TD doesn´t have the 1+1 backup function of orthogonal diversity transmission, which decreases its stability further. In TD, the value for half of the transmission chips is 0, so the transmission power and spectrum efficiency for user will be decreased.