Performance analysis of rate adaptation in cognitive wireless network over fading channel

Currently, the cognitive wireless network draws the great attention since it can effectively improve the spectrum efficiency based on its spectrum cognition. In this paper, we extend the definition of wireless cognitive network, which focuses on the channel quality cognition. By measuring the SNR (Signal-to-Noise Ratio) of received signal, cognitive wireless network based on channel quality cognition adjusts its transmission rate, which accordingly selects different modulation and demodulation technology in Physical Layer. In this paper, we first analyze the BER (Bit Error Rate) of various modulation and demodulation methods described in IEEE 802.11b. Then, we propose Nakagami-m distribution to simulate the fading channel of cognitive wireless network. We analyze the performance of cognitive wireless network over fading channel based on the IEEE 802.11 MAC (Medium Access Control) mechanism. Finally, we validate our model through various simulations and present the impact of fading channel on cognitive wireless network.