FPGA Implementation of Block Parallel DF-MPIC Detectors for DS-CDMA Systems in Frequency-Nonselective Channels

Multistage parallel interference cancellation- (MPIC-) based detectors allow to mitigate multiple-access interference in direct-sequence code-division multiple-access (DS-CDMA) systems. They are considered serious candidates for practical implementation showing a good tradeoff between performance and complexity. Better performance is obtained when decision feedback (DF) is employed. Although MPIC and DF-MPIC have the same arithmetic complexity, DF-MPIC needs much more FPGA resources when compared to MPIC without decision feedback. In this letter, FPGA implementation of block parallel DF-MPIC (BP-DF-MPIC) is proposed allowing better tradeoff between performance and FPGA area occupancy. To reach an uncoded bit-error rate of 10−3, BP-DF-MPIC shows a 1.5 dB improvement over the MPIC without decision feedback with only 8% increase in FPGA resources compared to 69% for DF-MPIC.