An improved, non-data aided symbol timing recovery for GMSK modulated signals

Symbol timing recovery is a process of recovering the optimal sampling time that corresponds to the maximum opening of the eye diagram. Most of the existing algorithms for the timing recovery of GMSK signals are either data aided or have large computational complexity. In this paper we present a low complexity, feedback and non-data aided timing recovery scheme for GMSK signals. This technique is based on the Gardner´s timing error detector. Gardner´s timing error detector was actually proposed for PSK signals with raised cosine pulse shapes but we show that it can be successfully applied on the CPM signals as well. The open loop statistical S-curve is computed to show the controlled and stable close loop performance