Title :
Performance of OFDM/CDMA system with turbo coding in a multipath fading channel
Author_Institution :
Dept. of Electr. Eng., Princeton Univ., NJ, USA
fDate :
5/1/1999 12:00:00 AM
Abstract :
The performance of an OFDM/CDMA system with turbo coding is analyzed and simulated in a multipath fading channel. The bit error probability is derived for a frequency-selective Rayleigh fading channel. In the OFDM/CDMA system, OFDM and CDMA are combined to exploit the advantages of both techniques. For decoding the turbo code, a MAP decoding algorithm is employed. Implementation issues are discussed for OFDM, a CDMA system, and a turbo decoding procedure. From the simulation results, it is demonstrated that turbo coding offers considerable coding gain with reasonable encoding/decoding complexity. Also, it is shown that the BER performance is substantially improved by increasing the interleaver length for a fixed code rate and the increasing number of iterations used in the decoding process. The results in the paper can be applied to the design of OFDM-based CDMA system
Keywords :
OFDM modulation; Rayleigh channels; code division multiple access; error statistics; iterative decoding; maximum likelihood decoding; multipath channels; multiuser channels; nonlinear distortion; turbo codes; BER performance; FFT; MAP decoding algorithm; OFDM/CDMA system; bit error probability; coding gain; encoding/decoding complexity; fixed code rate; frequency-selective Rayleigh fading channel; interleaver length; iterative decoding; multipath fading channel; nonlinear distortion; simulation results; system design; turbo coding; turbo decoding; Channel coding; Digital audio broadcasting; Digital video broadcasting; Fading; Iterative decoding; Mobile communication; Multiaccess communication; OFDM modulation; Quality of service; Turbo codes;
Journal_Title :
Consumer Electronics, IEEE Transactions on
