Iterative multi‐channel FH‐MFSK reception in mobile shallow underwater acoustic channels. Issue 5 (1st March 2020)

• Record Type: Journal Article
• Authors: Sun, Dajun; Hong, Xiaoping; Cui, Hongyu; Liu, Lu
• Is Part Of: IET communications. Volume 14:Issue 5(2020)
• Page Start: 838
• Page End: 845
• Publication Date: 2020-03-01
• Subjects: multipath channels -- underwater acoustic communication -- modulation coding -- wireless channels -- frequency shift keying -- radio receivers -- channel coding -- frequency hop communication -- convolutional codes -- iterative decoding -- mobile computing -- maximum likelihood estimation; iterative multichannel FH‐MFSK reception -- mobile shallow underwater acoustic channels -- frequency‐hopped M‐ary frequency‐shift‐keyed -- high ambient noise -- rapid phase fluctuation -- robust modulation scheme -- convolutionally encoded FH‐MFSK modulation scheme -- novel iterative multichannel reception -- decoding -- multichannel soft‐input–soft‐output demodulator -- long multipath delay -- noniterative receiver -- noise figure 5.5 dB -- size 300.0 m; Telecommunication systems -- Periodicals; Speech processing systems -- Periodicals; 621.38205
• DOI: 10.1049/iet-com.2019.1045
• Languages: English
• ISSNs: 1751-8628

Abstract

Abstract : Frequency‐hopped M‐ary frequency‐shift‐keyed (FH‐MFSK) has the ability to handle with long multipath, large Doppler spreads, high ambient noise and rapid phase fluctuation, and is proved to be a robust modulation scheme in mobile shallow underwater acoustic channels. Aiming at this topic, a convolutionally encoded FH‐MFSK modulation scheme with a novel iterative multi‐channel reception is proposed. To obtain the novel reception suitable for non‐coherent M‐ary frequency‐shift‐keyed, the ideas of iterative multi‐channel demodulation and decoding are combined and extended. A modified multi‐channel soft‐input–soft‐output demodulator based on maximum‐a‐posterior criterion is derived, and substantial gains of several decibels in power efficiency are achieved. Extra gain can be obtained by utilising time diversity with long multipath delay. Simulation shows that a non‐coherent receiver equipped with five arrays obtains around 5.5 dB gain over the single non‐iterative receiver. A shallow water field testing at Songhua Lake with 300 m distance confirms that the proposed receiver verifies its robustness and usability.