A Novel Approach for the Estimation of Doubly Spread Acoustic Channels Based on Wavelet Transform

Abstract

Abstract:In this paper, the estimation of doubly spread underwater acoustic (UWA) channels is investigated. The UWA channels are characterized by severe delay spread and significant Doppler effects, and can be well modeled as a multi-scale multi-lag (MSML) channel. Furthermore, exploiting the sparsity of UWA channels, MSML channel estimation can be transformed into the estimation of parameter sets (amplitude, Doppler scale factor, time delay). Based on this, the orthogonal matching pursuit (OMP) algorithm has been widely used. However, the estimation accuracy of OMP depends on the size of the dictionary, which is related with both delay spread and Doppler spread. Thus it requires high computational complexity. This paper proposes a new method, called wavelet transform (WT) based algorithm, for the UWA channel estimation. Different from OMP algorithm which needs to search in both time domain and Doppler domain, WT-based algorithm only needs to search in time domain by using the Doppler invariant characteristic of hyperbolic frequency modulation (HFM) signal. The performance of the proposed algorithm is evaluated by computer simulations based on BELLHOP. The simulation results show that WT-based algorithm performs slightly better than OMP algorithm in low signal to noise ratio (SNR) while can greatly reduce computational complexity.

Dynamic Parameter Identification of a Long-Span Arch Bridge Based on GNSS-RTK Combined with CEEMDAN-WP Analysis

“…Additionally, a few novel EMD methods have been proposed in recent years (e.g., the step-by-step EMD method [17,18] and the wavelet-bounded EMD method [19,20]). Just as in EMD, the traditional wavelet is another efficient technique and has been widely applied in signal processing domain [21][22][23][24][25]. The wavelet packet (WP) is a popularization of the traditional wavelet, which can divide the frequency domain adaptively [26].…”

A Prefix Based Approach for Joint Doppler and Channel Estimation in Underwater Communication

“…The proposed algorithm is compared with the wavelet-based channel estimation suggested in [27]. It can be observed from figures that the performances of proposed Doppler scale estimation method outperforms the method proposed in [27] by orders of magnitude, except for the Doppler scale value of η = 1.01, in this case, the performance improvement is marginal at low SNR. Similarly, the delay estimation using the proposed method also performs significantly better than that of [27].…”

“…Moreover two signals, in turns, puts a limit on the data rate. To overcome this issue a single prefix to jointly estimate Doppler scale and channel is proposed in [27], though it do not compromise with data rate, but the estimation error increases with the increase in Doppler.…”

“…Fig.22Performance of the proposed algorithm for channel estimation with SNR: A1: wavelet based algorithm[27],A2 : proposed algorithm.…”

Editorial for Special Issue: Underwater Acoustics, Communications, and Information Processing

“…To develop a practical channel model through analysis, applicable to realistic ocean applications, Zhang et al estimated doubly spread acoustic channels based on wavelet transform (WT) in [7]. Typically, a simple model represents underwater acoustic channels, usually with severe delay spread and significant Doppler effects.…”