Spectrum-Efficient Distributed Compressed Sensing Based Channel Estimation for OFDM Systems Over Doubly Selective Channels

Abstract

In this paper, we deal with channel estimation (CE) for high-mobility orthogonal frequency division multiplexing (OFDM) systems. To make the numerous (unknown) estimation for the high-mobility OFDM systems practicable, the channels are assumed to be time-and frequency-selective−or doubly selective (DS) and approximated by a basis expansion model (BEM). As the DS channel requires the distributed acquisition of multiple correlated signals in the delay-Doppler channel domain, we proceed to estimate jointly sparse BEM coefficient vectors over a DS channel as against numerous channel coefficients. On account of channel time-variation, the resulting channel matrix in the frequency domain exhibits (approximately banded) pseudo-circular structure, which gives rise to a diagonally dominant yet full matrix rather than a diagonal matrix and thus induces inter-channel interference (ICI). On the premise of this observation, we propose a new pilot design scheme that identifies the optimal pilot placement and values for each pilot cluster to combat ICI. Furthermore, to obtain a channel estimator consistent with the jointly sparse delay-Doppler [i.e., two dimensional (2D)] channel model, an algorithm namely, distributed compressed sensing (DCS)-based stage determined matching pursuit (DCS-SdMP), is proposed. Our claims are supported by simulation results, which are obtained considering Jakes' channels with fairly high Doppler spreads, which show the superiority of the proposed schemes over other different methods of CE. INDEX TERMSChannel estimation (CE), doubly selective (DS) channel, orthogonal frequency division multiplexing (OFDM), distributed compressed sensing (DCS), basis expansion model (BEM), pilot design, wireless communication.

A Comprehensive Survey on Millimeter Wave Communications for Fifth-Generation Wireless Networks: Feasibility and Challenges

“…5G systems are envisioned to realize data rates up to 150 Mbps UEs traveling at speeds up to 500 km/h in high-speed railway (HSR) scenarios. However, future high-mobility OFDM system communications such as express railroad trains for 5G wireless networks manage a fading operating environment of time-and frequencyselective-or doubly selective (DS)-fading [311]. The effect of DS fading is due to high Doppler frequency spread (DFS) (i.e., frequency dispersion -time selectivity) and multipath effects (i.e., time dispersion-frequency selectivity) in wireless links [311].…”

Time-Varying Sparse Channel Estimation Based on Adaptive Average and MSE Optimal Threshold in STBC MIMO-OFDM Systems

“…The simulation is performed in the time-varying multipath environments with different Doppler spread. For obtaining a comprehensive evaluation of the proposed AMA-IMOT method, three sparse channel models, namely Channel-A [18], Channel-B [28], and Channel-C [35], with different channel sparsity degrees and power delay profiles . The Channel-B is the advanced television technology center (ATTC) and the Grand Alliance DTV laboratory's ensemble E model, while the Channel-C model is the Hilly Terrain channel.…”

“…On the other hand, according to the data fusion principle, Uwaechia et al [35] built a CS collaborative framework by combining OMP, ROMP and other CS algorithms, which can significantly improve the signal recovery performance. However, the above mentioned CS algorithms [32]- [35] often require a large number of iterations to correct approximation errors [36], so its computational complexity is high. Moreover, a prior KCS about channel sparsity degree is often necessary for the GP-based CS algorithms to achieve the optimal performance.…”

“…For sparse channel, the number of the nonzero CIR taps is much smaller than the maximum channel delay spread, the Algorithm 1 Searching the optimal average frame number Variable Declaration: 2 n  : estimated LS noise variance according to (32) d f : estimated Doppler spread according to (35)…”

A Novel Noise Suppression Channel Estimation Method Based on Adaptive Weighted Averaging for OFDM Systems

“…Orthogonal frequency division multiplexing (OFDM) technology is widely used in modern communication systems for its superior performance and high spectral efficiency [1,2]. The cyclic prefix (CP) is inserted between the adjacent OFDM symbols as a guard interval (GI), which not only reduces the inter-symbol interference (ISI) largely, but also simplifies the design of the frequency-domain equalizer [3].…”