Performance Simulation of an EM-Based Iterative Receiver for Underwater Acoustic OFDM System

Abstract:

In this paper, an expectation maximization (EM) algorithm based iterative receiver is utilized in the underwater acoustic OFDM system to improve the spectrum efficiency. A relatively smaller number of pilots are used to determine the initial value for the EM-based channel estimation process. The intermediate estimates of the channel state information generated by the EM algorithm are fed forward to the BCJR decoding unit to achieve the a posterior probability of the transmitted bit sequence. The a posterior probability is then fed back to the EM algorithm to estimate channel state information. The iterative receive process is expected to realize a better channel estimate and bit error rate (BER) performance. Simulation results demonstrate that the EM-based iterative underwater acoustic OFDM system has a fast convergence property, and can achieve a low mean square error (MSE) for the channel estimation and a near optimal BER performance.

• Periodical: Applied Mechanics and Materials (Volumes 543-547)
• Pages: 547-553
• DOI: https://doi.org/10.4028/www.scientific.net/AMM.543-547.547
• Online since: March 2014
• Authors: Yan Fei Zhang*, Ying Wang, Rong Xi He
• Keywords: BCJR Decoding Algorithm, EM Algorithm, OFDM, Underwater Acoustic Channel

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