BER Performance Improvement in Coded-OFDM Systems Using Equalization Algorithms

Intersymbol interference is a major cause to limit high data rate transmission in wireless communication. To avoid ISI OFDM is the preferred modulation technique. For frequency selective channels pure OFDM may not be sufficient to eliminate ISI. The use of time coding (interleaver and convolution coder) improves the ISI affected reception but do not eliminate ISI completely. The paper investigates the presence of equalizers to improve BER performance in ISI affected reception. The performance improvement is observed for two novel equalizers namely zero forcing equalizers and MMSE equalizers. Simulation results are presented to demonstrate the superiority of the CODED OFDM method with equalizers

[1]  R.F. Ormondroyd,et al.  A high efficiency channel estimation and equalisation strategy for a broadband COFDM system , 1998, 1998 URSI International Symposium on Signals, Systems, and Electronics. Conference Proceedings (Cat. No.98EX167).

[2]  Paolo Banelli,et al.  Theoretical analysis and performance of OFDM signals in nonlinear fading channels , 2003, IEEE Trans. Wirel. Commun..

[3]  M.D. Haque,et al.  Performance evaluation of a wireless Orthogonal Frequency Division Multiplexing system under various concatenated FEC channel-coding schemes , 2008, 2008 11th International Conference on Computer and Information Technology.

[4]  Georgios B. Giannakis,et al.  Cyclic prefixing or zero padding for wireless multicarrier transmissions? , 2002, IEEE Trans. Commun..

[5]  Emad S. Hassan,et al.  Enhanced performance of OFDM and single-carrier systems using frequency domain equalization and phase modulation , 2009, 2009 National Radio Science Conference.

[6]  Ramjee Prasad,et al.  An overview of OFDM and related techniques towards development of future wireless multimedia communications , 2002, Proceedings RAWCON 2002. 2002 IEEE Radio and Wireless Conference (Cat. No.02EX573).

[7]  J.A.C. Bingham,et al.  Multicarrier modulation for data transmission: an idea whose time has come , 1990, IEEE Communications Magazine.

[8]  Paulo S. R. Diniz,et al.  Suboptimal Linear MMSE Equalizers With Minimum Redundancy , 2010, IEEE Signal Processing Letters.

[9]  Zhi-Quan Luo,et al.  Minimum BER block precoders for zero-forcing equalization , 2002, 2002 IEEE International Conference on Acoustics, Speech, and Signal Processing.

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

[11]  Georgios B. Giannakis,et al.  OFDM or single-carrier block transmissions? , 2004, IEEE Transactions on Communications.

[12]  A. Mammela,et al.  Channel estimation versus equalization in an OFDM WLAN system , 2001, IEEE VTS 53rd Vehicular Technology Conference, Spring 2001. Proceedings (Cat. No.01CH37202).

[13]  Andrew C. Singer,et al.  Minimum mean squared error equalization using a priori information , 2002, IEEE Trans. Signal Process..