Performance Analysis of the Detection Methods for SFBC-OFDM Communication Systems in a Fast Fading Channel

Abstract

MIMO-OFDM systems have increased the diversity gain and provide higher data rates. For high performance 4G wireless communication, we use MIMO-OFDM employing Space Frequency Block Codes (SFBC) which provides spatial diversity in fast fading environments. By converting the codes from time domain to frequency domain, the MIMO-OFDM schemes apply Alamouti coding directly to OFDM technique. SFBC technique encodes a pair of input bits wherein each symbol is transmitted from two antennas over two sub-carriers. On the receiver side we analyze four detection methods including Simple maximum-likelihood (SML), Joint maximum-likelihood (JML), Zero-forcing (ZF) and Decision-feedback (DF). The evaluation of the detection methods is done on the basis of the SNR (Signal to Noise Ratio), BER (Bit Error Rate) and complexity of implementation in fast fading channels under three vehicular speeds i.e. 30km/hr, 60km/hr and 120km/hr. Using the results obtained from both mathematical expressions and numerical simulations, we compare the presented schemes and show their significant advantages.