Frequency and time synchronization for the CDMA array-receiver STAR with interference subspace rejection
Besma Smida, Sofiène Affes, Paul G. Mermelstein · 2003
The paper investigates the problem of CDMA multiuser detection with STAR-ISR (spatio-temporal array receiver with interference subspace rejection) in the presence of an unknown multipath channel and residual carrier offset. We observe that the performance of STAR-ISR could be seriously degraded if no frequency-offset recovery is implemented. We introduce an efficient carrier frequency offset recovery (CFOR) module into STAR-ISR. The proposed CFOR is based on space/time separation that implements a simple linear regression approach for both time-delay and frequency synchronization. We analyze the performance of STAR-ISR with and without CFOR. Simulations show that CFOR reduces the performance loss due to the frequency offset. With frequency offset of 600 Hz, the link-level gain is more than 7 dB for 8PSK users.