DF-DD for multi-chip differentially encoded DS-CDMA

We propose decision-feedback differential detection (DF-DD) for direct-sequence code-division multiple access (DS-CDMA) with multi-chip (MC) differential encoding (DE). While the complexity of the novel receiver is moderate, it enables large performance gains over conventional differential detection for various channel environments. Furthermore, we show that, in most cases, MC-DE outperforms single-chip differential encoding and, in addition, decreases receiver complexity. Another result of the paper is that quaternary differential phase-shift keying (QDPSK) is more suitable for chip-level DE than binary DPSK (BDPSK).