Joint Channel Estimation and Symbol Detection for OFDM Systems in Rapidly Time-Varying Sparse Multipath Channels

Abstract

In this paper, we propose a space-alternating generalized expectation maximization (SAGE) based joint channel estimation and data detection algorithm in compressive sensing (CS) framework for orthogonal frequency-division multiplexing (OFDM) systems in rapidly time-varying sparse multipath channels. Using dynamic parametric channel model, the sparse multipath channel is parameterized by a small number of distinct paths, each represented by the path delays and path gains. In our model, we assume that the path gains rapidly vary within the OFDM symbol duration while the number of paths and path delays vary symbol by symbol. Since the convergency of the SAGE algorithm needs statistically independent parameter set of interest to be estimated, we specifically choose the discrete orthonormal Karhunen-Loeve basis expansion model (DKL-BEM) to provide statistically independent BEM coefficients within one OFDM symbol duration and use just a few significant BEM coefficients to represent the rapidly time-varying path gains. The resulting SAGE algorithm that also incorporates inter-channel interference cancellation updates the data sequences and the channel parameters serially. The computer simulations show that our proposed algorithm has better channel estimation and symbol error rate performance than that of the orthogonal matching pursuit algorithm that is commonly proposed in the CS literature.

Time-Domain Channel Estimation Scheme for OFDM over Fast Fading Channels

“…Recently, index modulation-OFDM-spread spectrum (IM-OFDM-SS) [7] and low-redundant energy UW-OFDM (LRE-UW-OFDM) [8] schemes have been proposed to improve the spectral and energy efficiencies, respectively, in OFDM systems. OFDM has been extensively used in wired and wireless application, digital audio/video broadcast (DAB/DVB), and many standards such as IEEE 802.16a and IEEE 802.11e [9,10].…”

Structured Distributed Compressive Channel Estimation Over Doubly Selective Channels

“…O RTHOGONAL frequency division multiplexing (OFDM) is an attractive communication system because of its robustness against frequency-selective (FS) fading channels, high data rate transmission capability and high spectral efficiency. Recently, OFDM has gained its popularity in a number of wireless broadband communication systems, such as the digital video broadcasting (DVB) system, IEEE802.16e (WIMAX), and 3GPP long-term evolution (LTE) systems [1]- [3]. As the accurate channel state information (CSI) can notably improve system performance, it is necessary to provide a reliable channel estimation method [4].…”