OFDM for Wireless Communications Systems
OFDM for Wireless Communications Systems
Stochastic Modeling and Performance Evaluation of Fading Channel for Wireless Network Design
AINAW '07 Proceedings of the 21st International Conference on Advanced Information Networking and Applications Workshops - Volume 02
Performance analysis of the IEEE 802.11 distributed coordination function
IEEE Journal on Selected Areas in Communications
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Orthogonal Frequency Division Multiplexing (OFDM) and multiple antennas are being used in various standards of Wireless Local Area Network (WLAN) to enhance data rates and to achieve higher reliability in fading channel conditions. Channel modeling plays a crucial role, especially in wireless environment, in evaluating the performance of physical layer in fading environment. The paper presents a Finite State Markov (FSM) channel model, for computation of fading channel performance measures. Frequency and duration analysis is proposed to evaluate the performance of WLAN physical layers for OFDM, OFDM with Selection Combining (SC) and OFDM with Maximum Ratio Combining (MRC) diversity techniques. Level Crossing Rate (LCR) and Average Fade Duration (AFD) are computed with the analysis of FSM model. Bit Error Rate (BER) is then calculated with the help of LCR and AFD. LCR, AFD and BER performances are compared for three physical layers with varying fade depths and for different values of Signal to Noise Ratio (SNR). Results show that OFDM with MRC gives minimum value of BER for fade depths more than 0dB, while BER is minimum for OFDM with SC for fade depths below 0dB. OFDM with diversity always outperforms than OFDM without diversity for all values of fade depths.