Soft-in/soft-out noncoherent sequence detection for Buetooth: capacity, error rate and throughput analysis

This paper investigates an energy efficient, noncoherent system design for Bluetooth. We propose using a soft decision differential phase detector (SDDPD) along with the (15, 10) shortened Hamming channel (SHC) code. Unlike previous work, where SDDPD with ML detection gives hard estimates of the modulated bits, we develop a sequential, soft-in/soft-out (SISO) SDDPD which exchanges soft information with the channel decoder. The proposed soft decision based receiver gives significant improvements in energy efficiency and throughput over the benchmark Bluetooth receiver using limiter discriminator integrator (LDI) detection with hard decision channel decoding. It also outperforms SDDPD with ML detection followed by hard decision channel decoding. Additional gains are obtained by extending our proposed system to perform bit-interleaved coded modulation (BICM). The effect of bit-interleaving on the performance of LDI detection and SDDPD with hard decision decoding is studied. The capacity of our system under BICM is evaluated and extrinsic information transfer (EXIT) chart analysis is used to analyze convergence behavior of the proposed receiver