Performance of Underwater Acoustic Channel using modified TCM OFDM coding techniques

Abstract

Factors that limits the achievable data rate in Underwater Acoustic Channel (UAC) are high path loss, Inter-Symbol Interference (ISI), and Doppler Shift. To overcome these difficulties, Orthogonal Frequency Division Multiplexing (OFDM) is combined with Trellis Coding Modulation (TCM) techniques. In our paper, the error rate are calculated with code rate of ½ and 2/3 with all possible polynomials and the best five polynomial with least error rate are listed for discussion. The result shows that the polynomial whose code word having minimum hamming distance gives least error rate for UAC channel. Error rate is also compared with the Binary Phase Shift Keying (BPSK), Error Correcting Codes like Walsh, Hadamard, Pseudo Noise (PN) Sequence with both binary data and sample image.