CS-CDMA/CP With the Chu Sequence: A Bandwidth-Efficient Multi-Access Scheme for Fast Fading Multipath Channels
In this paper, Convolutional Spreading CDMA with Cyclic Prefix (CS-CDMA/CP) employing the Zero-Correlation-Zone (ZCZ) code generated from the Chu sequence is proposed as a novel multi-access scheme for fast fading multipath channels. Analysis results demonstrate that the system remains approximately Multi-User Interference (MUI)-free even when the system is heavily loaded and subject to severe Doppler spreads. An effective channel estimation method based on B-spline approximation is also proposed. Simulation results show, in combination with the Probabilistic Data Association (PDA) equalization, the system significantly outperforms the DS-CDMA system employing Linear Minimum Mean Squared Error (LMMSE) chip-wise equalization and polynomial interpolation-based channel estimation from medium to high user population.