Performance Evaluation of Turbo Decoding in DFTS-OFDM Systems Over V2V Channel

Vehicle-to-vehicle (V2V)doubly-dispersive channels cause loss of orthogonality in multi-carrier systems, resulting in inter-carrier interference (ICI). In order to suppress ICI in orthogonal frequency division multiplexing (OFDM)systems, the techniques of forward error correction (FEC)and nonlinear detection of data are usually employed, requiring low coding rates and high decoding computational complexity. In this paper, different configurations for reception of OFDM signals with frequency dispersion, discrete Fourier transform-spread-OFDM (DFTS-OFDM)are explored including FEC techniques and linear/nonlinear detection. The results show that the use of turbo encoding and non-linear detection of ordered successive interference cancellation (OSIC)in the DFTS-OFDM system offers significant gains in terms of performance when compared to conventional OFDM receivers, obtaining a performance in terms of bit error rate (BER)of 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-4</sup> with a signal-to-noise ratio (SNR)close to 7 dB over doubly selective channel with 1 kHz Doppler spread. The results found can be applied in the design of communication systems with high mobility.