Shortwave Communication Iterative Equalization And Decoding With Low Complexity To Achieve

HF(High Frequency) communication is widely used in military wireless communications. One of the important tasks to improve the throughput in HF channel is to find the method to conquer the severe time-varying intersymbol interference(ISI) as well as additive noise. The aim of the article is to find one low-complexy digital method which is able to be applied on hardware and can get a low bit-err-rate in severe HF channel. Conventional HF receivers perform adaptive equalization to mitigate the ISI, perform error-correcting coding (ECC) and error-correcting decoding (ECD) to mitigate additive noise. The equalizater and decoder are apart sub-systems under that design which is suboptimal because the equalizer does not make use of the redundancy introduced by ECC and the ECC also can't make use of the channel information to perform soft-input-and-soft-output decoding. In my acticle, one outperformed system is adopted to use iterative equalization and decoding (IED), a.k.a Turbo equalization, which has a good command of information transfer between the two sub-systems. The simulated results illuminate the necessary of IED. Tüchler.M, the foreign scholar, fully explained the IDE of low-level modulation. My article addresses this method and the IDE of multilevel modulation combined with the iterative demapping and decoding (IDD) advanced by S.Ten Brink. Tüchler.M's method has operations of product and reverse of a high complexity channel matrix, which brings the difficulty to be realized on hardware. My article has illustrated the low-complexity IDE both in time domain and frequency domain to perform IDE.