Application and study of code technique in SC-FDE system

WANG Ke， LIU Shun-lan
（College of Communication Engineering， Hangzhou Dianzi University， Hangzhou 310018， China）

Abstract： Aiming at the high bit error rate（BER）and unreliability of traditional single carrier frequency domain equalization（SC-FDE）in complex multipath environment，where the channel is changing rapidly and Doppler frequency shift is large，SC-FDE system based on LDPC and Turbo code were studied and their modeling were bulit respectively. Under the air Ricean channel，the curve of systemic signal-to-noise ratio with the bit-error-ratio was simulated by Matlab. The simulation results indicate that the BER of SC-FDE system with code technique has dramaticlly reduced. When the input of SNR is 14dB，the BER of SC-FDE system based on LDPC is closed to．In ground to air channel，compared with the SC-FDE system based on Turbo code，the SC-FDE system based on LDPC code achieves 1 dB coding gain and does not have error-floors when BER is about．Therefore the SC-FDE system based on code technique can enhance the reliability of the information transmission，to meet requirements of high speed and efficient of future communication．
Key words： single carrier frequency domain equalization（SC-FDE）；LDPC code；Turbo code；bit error rate（BER）；Ricean channel