Non-coherent differential encoded multi-carrier SS modulation schemes using low-rate orthogonal convolutional coding in frequency selective Rayleigh fading

This paper investigates the performance benefits of applying convolutional coding and interleaving to a non-coherent DS-CDMA system using OFDM to combat the bit-error rate degradation suffered in a frequency selective Rayleigh faded channel. The channel model is typical of the mobile radio environment with Doppler effects and frequency selective Rayleigh fading. The paper also compares the performance of the coded OFDM-CDMA system with a conventional single-carrier DS-CDMA system which uses a RAKE receiver to combat fading. Finally, a comparison is made between the performance of ordinary convolutional codes and low-rate orthogonal convolutional codes (LROCC). It is found that the LROCC-OFDM system outperforms both the OFDM-CDMA and DS-CDMA RAKE systems quite substantially when interleaving is used.