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This paper proposes a computationally efficient, linear minimum mean square error (MMSE) channel estimation algorithm based on KL series expansion for OFDM systems. Based on such expansion, no matrix inversion is required in the proposed MMSE estimator. Moreover, truncation in the linear expansion of channel is achieved by exploiting the optimal truncation property of the KL expansion resulting in...
In this paper, different techniques for the estimation of the signal parameters and/or the channel coefficients for single-input/multiple-output systems, arc presented. These methods arc based, cither on the use of a small part of observations or on the minimization of a quadratic form with quadratic constraint. Simulations have been established and these techniques arc compared to the classical approaches.
The problem of recovering a digital communication signal distorted by a linear time-invariant channel and contaminated by severe co-channel or adjacent-channel digital interference is addressed in this paper. The proposed linear periodically time-varying (LPTV) receiver jointly performs channel equalization and interference suppression, without requiring explicit knowledge or estimation of the interfering...
A novel multiuser semiblind demodulation scheme is proposed. Channel estimation is carried out according to the Maximum Likelihood (ML) principle and using the Expectation Maximization (EM) algorithm. Afterwards, the channel state information is used to implement the joint optimum detector with a dynamic programming algorithm (e.g. the Viterbi algorithm). The resulting demodulator is termed semiblind...
In this paper, we investigate the performance of the low-complexity algorithms based on Likelihood Ascent Search (LAS) and Tabu Search (TS) for detection in MIMO systems with channel estimation errors. Here, we briefly review the algorithms for LAS and TS and their variants and subsequently compare them for various MIMO settings. We provide the simulation results for BER performance in 2× 2, 4× 4...
In this work, the problem of receive antenna selection (AS) is considered, in a multiple antenna communication system having a single radio frequency (RF) chain at the receiver. The AS is performed on a per-packet basis, and AS decisions are based on noisy estimates of the channel gains obtained using pilot symbols embedded in the data packet for coherent demodulation, along with the receiver's knowledge...
We propose a precoder design to minimize the codeword error rate of multiple-input multiple-output (MIMO) systems in the presence of channel estimation errors. Our proposed scheme only requires knowledge of the second-order statistics of the channel, noise and the estimation errors; an estimate of the instantaneous channel state information (CSI) is not required. Compared to the instantaneous CSI...
This paper presents a collaborative beamforming design under imperfect channel state information (CSI) assumption for a multiple single-antenna two-way relay network with reciprocal channels. In practical scenario, the channel estimation is always inaccurate at relay nodes. Aiming to tackle the performance degradation caused by the imperfect CSI, we propose a robust beamforming scheme with hypothesis...
Time domain synchronous OFDM (TDS-OFDM) has higher spectrum efficiency than standard cyclic prefix OFDM (OFDM) by replacing CP with a known training sequence as the guard interval of OFDM data block, but severe mutual interferences will be caused in multipath channels. Recent studies have shown that the theory of compressive sensing (CS) can be efficiently applied to achieve reliable channel estimation...
To estimate multiple-input multiple-output (MIMO) channels, invariable step-size normalized least mean square (ISSNLMS) algorithm was applied to adaptive channel estimation (ACE). Since the MIMO channel is often described by sparse channel model due to broadband signal transmission, such sparsity can be exploited by adaptive sparse channel estimation (ASCE) methods using sparse ISS-NLMS algorithms...
In this paper we introduce an adaptive channel estimation scheme for two-way relay with node capability. The adaptive filter used is called Block Fast Array Multichannel 2D-Recursive Least Square (BFAM 2D-RLS). The modulation used is Orthogonal Frequency Division Multiplexing (OFDM) and channel estimation is done in the frequency domain. The proposed channel estimator considers correlation of channel...
In this paper, we study the optimization of the achievable rates of frequency-division-duplex (FDD) massive multiple-input-multiple-output (MIMO) systems with spatially correlated channels, by designing the downlink channel training sequences and the uplink channel feedback codebooks. In particular, the optimal channel training sequences and a Karhunen-Loeve transform followed by entropy coded scalar...
In this paper, the problem of transmitting an analog Gaussian source over an additive white Gaussian noise (AWGN) channel in the presence of a Gaussian interference known only at the transmitter is investigated. Our goal is to estimate both the analog source and the channel state at the receiver simultaneously. In this work, we present different transmission schemes based on joint source-channel coding...
Two training schemes namely the orthogonal pilot scheme (OPS) and the superimposed pilot scheme (SPS) are compared in terms of achievable rates in multiple-antenna fading channels with memory. For both schemes, we show that the achievable rate depends on the number of antennas, signal-to-noise ratio (SNR) and fading speed via the channel estimation error variance and the fraction of time for data...
Pilot contamination problem in massive MIMO networks operating in time-division duplex (TDD) mode can limit their expected capacity to a great extent. This paper addresses this problem in cosine modulated multitone (CMT) based massive MIMO networks; taking advantage of their so-called blind equalization property. We extend and apply the blind equalization technique from single antenna case to multicellular...
Underwater acoustic (UWA) communication channel features relatively fast time variation. Spatial modulation (SM) combined with orthogonal frequency division multiplexing (OFDM) transmission can be applied to UWA communications. Channel estimation may induce a performance penalty for SM since only one transmit antenna is activated to carry pilots. Recently, a differential solution has been proposed...
In this paper, we consider massive multiple-input multiple-output (MIMO) multicell systems with very large antenna arrays at base station (BS). We propose an eigenvalue decomposition (EVD) approach to evaluate the covariance matrix of the received vector at the BS, and focus on a physical channel model where the angular domain is partitioned into a finite number of directions, so-called angle of arrival...
Digital television terrestrial broadcasting (DTTB) industry has achieved rapid development in recent years. It is now facing new development opportunities for next-generation wireless broadcasting systems. As one of the DTTB standards, digital terrestrial multimedia/television broadcasting (DTMB) uses the time domain synchronous OFDM (TDS-OFDM) as its basic core technology. TDS-OFDM has higher spectral...
In the current literature considering multi-cell multi-user massive multiple-input multiple-output (MU-Massive-MIMO) systems, equal uplink power allocation among users is typically assumed, which does not exploit the potential of peruser power control. By contrast, in this paper we apply multi-cell uplink power control, assuming the minimum mean-square-error receiver based on the pilot contaminated...
Emerging wireline transmission systems such as G.fast use bands up to around 200 MHz on short cables. A key enabler for achieving the aspired throughput of several hundred Mbit/s is joint processing of transmit signals in downstream direction as well as joint processing of receive signals in upstream direction through techniques referred to as vectoring. A new challenge in such systems are sudden...
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