A novel symbol synchronization algorithm and low-complexity circuits design for zero-IF GFSK demodulator

Gaussian frequency shift keying (GFSK) is widely used in low power and low cost communication. This paper proposes a novel data-aided symmetry correlation symbol synchronization algorithm (DSCSSA) using the symmetry property of the received signals in zero-IF GFSK demodulator. Compared with conventional schemes, the proposed symbol synchronization circuits based on DSCSSA are just composed of shift registers, XNORs, an adder, a comparator, and a delayer instead of filter(s), voltage-controlled oscillator (VCO), multi-bit multiplier or multi-bit divider. As a result, the designed circuits have much lower complexity. The mean index error of DSCSSA is 0.147 when Eb/N0 is 10. The symbol synchronization circuits are synthesized in UMC 1.8 V 0.18 μm process, and the results show that the symbol synchronization circuits consume only 0.74 μA current and occupy 0.22 mm2 of silicon area.