Comparative Evaluation of Fading Channel Model Selection for Mobile Wireless Transmission System

摘要

This paper compares the performance of Rayleigh, Rician and Log-normal distributions in mobile wireless transmission system. In these distributions link quality cannot be predicted accurately enough to achieve reliable performance because of the unpredictable nature of the time-varying channel at different mobile speeds in sub-urban environment and as a result it will be very difficult to select the appropriate model in the system design for proper implementation. Binary Phase Shift Keying signaling scheme is used to modulate the data to be analyzed for efficient transmission over the three different distributions at mobile speeds of 30 km/h, 60 km/h and 90 km/h at carrier frequency of 900 MHz. Square root raised cosine filter is used to convert the modulated signal to analog signal suitable for transmission. The received bits through the channel without mitigating technique over the three scenarios are analyzed and Bit Error Rate (BER) computed for comparison. The results obtained showed that Rayleigh distribution has the highest BER, while Rician distribution has the BER between the Rayleigh and log-normal at the different speeds considered. This implies that Rayleigh distribution is the best model to be adopted by communication systems engineers.