Analysis of Bit Error Rate in a Rician Channel with Additive White Gaussian Noise

Abstract

Wireless technology is not an exception. In fact, in recent years, the growth in telecommunication sector can be better described as astronomical. This work was carried out to analysis bit error rate of different modulation schemes to determine their performance under RICIAN channel with additive white Gaussian noise. Related works were reviewed, and MATLAB Simulink Modulation methods were also adopted using five-step approach. The result of the research work showed that the best performing modulation scheme under AWGN is the binary phase shift keying with 0.07 BER at 0dB signal to noise ratio. BPSK was followed in performance by 16-quadrature amplitude modulation that had about 0.15 BER at 0dB SNR. The third modulation scheme in terms of performance is differential binary phase shift keying which had about 0.17 BER at the SNR of 0dB. For the two channels, AWGN and RICIAN, AWGN had better performance; BER was lower under it than under RICIAN channel. This is true in all the modulation schemes used. At SNR of 3dB over AWGN, BPSK, 16-QAM, quadrature phase shift keying, and DBPSK BER were 0.023, 0.056, 0.150, and 0.067, respectively. But over RICIAN channel at the same SNR of 3dB BER for BPSK, 16-QAM, QPSK, and DBPSK BER were 0.028, 0.065, 0.194, and 0.078 respectively, indicating better performance of AWGN. From the graph too, at lower SNR, say 0dB or 1dB there was a linear increase in capacity. This is however different as the SNR increased. The graph shows that as SNR increases, the graph assumes a logarithmic shape. This indicates that capacity of communication system under AWGN will increase logarithmically at higher SNR. From the graph, for 0dB SNR, the capacity is 0, for 1dB SNR, the capacity is 1 and for 2dB SNR, the capacity is about 1.6 while for 7dB SNR, the capacity is about 3. In Conclusion, for low signal to noise ratio, the increase in system capacity due to AWGN is linear, but if the SNR is high the observed increase in capacity due to AWGN is logarithmic. Also, the BPSK performed better and maintained the lowest BER compared to the other three modulation schemes (16-QAM, QPSK, and DBPSK) for various values of SNR ranging from 0 to 8 and the four modulation schemes studied performed better in AWGN channel than in Rician channel.