Impact of Doppler shift on the performance of RS coded non-coherent MFSK under Rayleigh and Rician fading channels

The relative motion of full-function PAN coordinator in a WPAN or WSN leads to a Doppler Shift in the frequency of the signal transmitted towards it. This Doppler Shift has its impact over the Bit Error Rate performance of modulation scheme incorporated in transceiver circuits of sensor nodes. By spreading the encoded stream of data using either FHSS or DSSS, this impact may easily be overcome. This paper is a comparative BER performance analysis of Reed-Solomon coded non-coherent M-ary FSK scheme with Direct Sequence Spread Spectrum. The simulations are run with common and all possible types of spectrum of Doppler Shift defined for both Rayleigh and Rician fading channel conditions using a MATLAB / Simulink model. The simulation results show that, there is an appreciable performance difference between the scheme with DSSS and the scheme without code spreading for channel with Rayleigh fading. However, the difference is not as much as the previous case for the channel with Rician fading.