BER performance comparison of low processing gain TDD-CDMA system with various spreading sequences in mobile fading channels

The bit-error-rate (BER) performance of low precessing gain (PG) time division duplex CDMA (TDD-CDMA) system with joint detection (JD) multi-user detection (MUD) algorithms and different spreading sequences in dissimilar mobile radio propagation environments is compared in this paper. The sequences considered as spreading codes are Maximum-Length, Gold, Orthogonal-Gold, Random and Walsh-Hadamard sequences. The Zero Forcing-Block Linear Equalizer (ZF-BLE), Minimum Mean Square Error-Block Linear Equalizer (MMSE-BLE), Zero Forcing Block Decision Feedback Equalizer (ZF-BDFE) and Minimum Mean Square Error Block Decision Feedback Equalizer (MMSE-BDFE) JD algorithms are adopted in simulations. The mobile radio channels are Rural Area (RA), Typical Urban (TU) and Bad Urban (BU) channels. The result shows that under different propagation environments, the BER performance of each spreading sequence are different. The results obtained in this paper are very useful in the selection of sequence sets for TDD-CDMA system applications.