Feedback strategies for iterative channel estimation in OFDM underwater acoustic communications

• Published in: 高技术通讯（英文版） Vol. 24; no. 4; pp. 396 - 401
• Main Authors: Zhu Anfu, Li Xue
• Format: Journal Article
• Language: English
• Published: School of Electric Power, North China University of Water Resources and Electric Power, Zhengzhou 450045, P.R.China%College of Underwater Acoustic Engineering, Harbin Engineering University, Harbin 150001, P.R.China 01.12.2018
• Subjects: sparse channel estimation; orthogonal frequency division multiplexing ( OFDM); iterative feedback; underwater acoustic communication
• ISSN: 1006-6748
• DOI: 10.3772/j.issn.1006-6748.2018.04.008

The extremely limited bandwidth in underwater acoustic communication makes channel estima-tion using fewer pilot symbols more challenging.Iterative channel estimation ( ICE) can be used to refine channel estimation with limited number of pilots, by coupling the channel estimator with chan-nel decoder.In this paper, various feedback strategies in ICE are discussed.The performance of a decision feedback based on the cost function is improved by modifying the design and another four feedback strategies are summarized, including hard/soft decision feedback and their threshold-con-trolled versions.Simulation results show that ICE can achieve impressive gains over the non-iterative receiver and the gains are more significant with fewer pilots.Furthermore, soft decision feedback outperforms hard decision feedback;while the feedback based on the cost function and soft decision feedback have quite close performance.