Design of synchronous structure of receiver at very low SNR

Communication at very low signal-to-noise ratios(SNR) is of great importance for power limited satellite applications. Making use of the information between the encoded data, the iterative decoding algorithm makes decoding and synchronization together possible at very low SNR. Existing literatures mainly focus on the estimation of single parameter. However, parameters affect each other in practical systems, it is important to rationally design the order in which the parameters are estimated. This paper analyzes the estimation requirements of parameters, proposes a complete receiver structure with short frame header, selects a predictive algorithm to reduce the timing and frequency offset to a narrow range, and then improves the computational complexity of the iterative decoding algorithm. The simulation results show that the proposed scheme has good synchronization performance, high transmission efficiency and can tolerate large parameter deviations at very low SNR mode.