Computing Resource Multiplexed Carrier Synchronization Joint Coherent Demodulation of LEO Satellite Communication ASIC

Abstract

Digital application specific integrated circuit (ASIC) is increasingly used for low-earth orbit (LEO) satellite communication payloads due to its features of resistance to single event upset (SEU) and low power consumption. Because of the relatively high speed of LEO, large signal attenuation and various hostile interference, short-frame burst direct sequence spread spectrum (DSSS) becomes a common communication mode of LEO satellites. In order to meet the LEO communication ASIC requirements of low signal-to-noise ratio (SNR) threshold, short synchronization time and low logic resource consumption, a computing resource multiplexed carrier synchronization joint coherent demodulation (CMCSJCD) method is proposed in this study. Compared with the conventional FFT open-loop carrier synchronization and coherent demodulation method, it can save 33% of random access memory (RAM) resources and consumes none DSP4SE1 resources. When the SNR is greater than 3dB, the bit error rate (BER) of CMCSJCD is close to the theoretical value and CMCSJCD can work under low SNR circumstances. Currently, CMCSJCD has been used in several LEO satellite communication ASICs.