Energy Efficient Low-Complexity Symbol-by-Symbol GMSK Demodulator for BAN

We propose a symbol-by-symbol (SBS) detector for Gaussian minimum shift keying (GMSK) signals in body area networks (BAN). Our detector exploits the orthogonality between adjacent GMSK-modulated symbols. By dividing the received signals into inphase-/quadrature-channels and odd-/even-streams, the strongest inter-symbol interference (ISI) from the adjacent symbols is removed. A whitened matched filter is designed, and a decision-feedback scheme is proposed to further reduce the residue ISI. This SBS detector has much lower complexity than the conventional maximum likelihood sequence detection schemes using the Viterbi algorithm. Its performance can approach the MSK/BPSK performance which results in high energy efficiency. Thus, our proposed energy-efficient, low-complexity, SBS GMSK demodulator is suitable for BAN which have very limited resources. Based on our demodulator´s structure, several other SBS detectors can be obtained straightforwardly.