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Three Dimensional Concatenated Codes in OFDM Transmission System under a Rayleigh Fading Channel with Carrier Interference | ||
| Journal of Engineering and Sustainable Development | ||
| Article 1, Volume 12, Issue 2, 2008, Pages 137-156 | ||
| Author | ||
| Ghanim Abd AlKareem | ||
| Abstract | ||
| Orthogonal frequency division multiplexing (OFDM) or multicarrier transmission has been shown to be an effective technique to combat multipath fading in wireless Communications. It has been successfully used for HF (High frequency) radio applications and has been chosen as the standard for digital audio broadcasting and digital terrestrial TV broadcasting in Europe and high-speed wireless local areas networks. This paper describe the concept behind parallel data transmission and the configuration of an OFDM transmitter and receiver system when 8DPSK is used (8ary-Differential phase shift keying) as a modulation technique with the effect of carrier interference. First, the BER (Bit Error Rate) are evaluated for OFDM system in a two typical channels, AWGN channel and Rayleigh fading channel when we used a guard interval of 25% of symbol period compared with the theoretical channel performance for each channel. Second, the BER are evaluated for OFDM system in a Rayleigh fading channel with the effect of carrier interference for two values of carrier to interference ratio (CIR=15 dB & CIR=20 dB). In this case, some of subcarrier is completely lost by deep fades due to multipath fading and carrier interference. So, Forward Error Correcting (FEC) code is used to improve the performance of the OFDM system with carrier interference. Three techniques are used in this paper, the first technique a Reed Solomon code is used, the second technique a two dimensional concatenated codes is used and the 3rd technique a three dimensional concatenated codes is used which proposed in this paper. The results of a simulation are obtained by computer MATLAB v.7 language, improved the BER of the OFDM system with carrier interference & prove the robustness of the proposed three dimensional concatenated codes. | ||
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