Coded-OFDM in various multipath fading environments

In wireless communication, concept of parallel transmission of symbols is applied to achieve high throughput and better transmission quality. Orthogonal Frequency Division Multiplexing (OFDM) is one of the techniques for parallel transmission. It is used for a variety of broadband systems such as asymmetric digital subscriber lines, very-high-speed digital subscriber lines, digital video and audio broadcasting, and wide local area network standards such as IEEE 802.11a, IEEE 802.11g, and European telecommunication standard institute ( ETSI). However in fading environments the bit error rate (BER) increases. The performance can be improved by using some kind of channel coding. This form of OFDM is called coded-OFDM (COFDM). In this paper our aim is to analyze and compare the performance of COFDM in Additive white Gaussian Noise (AWGN), Rayleigh, Rician & Nakagami fading environments. The channel coding used is Reed Solomon (RS) code with 1/2 and 2/3 convolution codes. The performance parameter is BER and the mapping schemes used are BPSK, QPSK, 16-QAM and 64-QAM. All other parameters are as per IEEE 802.11a specifications.

[1]  P. Mohana Shankar,et al.  Simulation of flat fading using MATLAB for classroom instruction , 2002, IEEE Trans. Educ..

[2]  K. Vidhya,et al.  Development of Medical Image Compression Techniques , 2007, International Conference on Computational Intelligence and Multimedia Applications (ICCIMA 2007).

[3]  仲上 稔,et al.  The m-Distribution As the General Formula of Intensity Distribution of Rapid Fading , 1957 .

[4]  Serguei Primak,et al.  BER Analysis of Equalized OFDM Systems in Nakagami, m  <  1 Fading , 2007, Wirel. Pers. Commun..

[5]  Tung-Sang Ng,et al.  A simulation model for Nakagami-m fading channels, m<1 , 2000, IEEE Trans. Commun..

[6]  M. Nakagami.  The m-Distribution—A General Formula of Intensity Distribution of Rapid Fading , 1960 .

[7]  Li Tang,et al.  Analysis and simulation of Nakagami fading channel with MATLAB , 2003, Asia-Pacific Conference on Environmental Electromagnetics, 2003. CEEM 2003. Proceedings..

[8]  Yu Ted Su,et al.  Performance analysis of equalized OFDM systems in Rayleigh fading , 2002, IEEE Trans. Wirel. Commun..

[9]  Omar Daoud,et al.  Efficient performance of COFDM-based DVB-T , 2009, 2009 6th International Multi-Conference on Systems, Signals and Devices.

[10]  N.C. Beaulieu,et al.  A simple efficient method for generating independent Nakagami-m fading samples , 2005, 2005 IEEE 61st Vehicular Technology Conference.

[11]  S. Elnoubi,et al.  BER performance of GMSK in Nakagami fading channels , 2004, Proceedings of the Twenty-First National Radio Science Conference, 2004. NRSC 2004..

[12]  K. Thenmozhi,et al.  Suitability of Coded Orthogonal Frequency Division Multiplexing (COFDM) for Multimedia Data Transmission in Wireless Telemedicine Applications , 2007, International Conference on Computational Intelligence and Multimedia Applications (ICCIMA 2007).