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An Expectation-Maximization (EM) based scheme is presented in the context of compressed image transmission for blind Multiple-Input Multiple-Output (MIMO) wireless channel estimation. This cross-layer content-aware algorithm employs a combination of hard and soft (HS) symbol information from the header blocks of the scalable JPEG compressed image to estimate the complex baseband MIMO wireless channel...
Sphere decoding is a decoding technique able to achieve the maximum likelihood error performance in fading environments; nevertheless, it exhibits a high complexity, especially in poor channel conditions. In this paper, we present an adaptive hybrid algorithm which reduces the complexity of conventional sphere decoding without sacrificing its error performance. Through simulations, we prove that the...
The V-BLAST (Vertically-layered Bell Laboratories Layered Space-Time) algorithm is a multilayer symbol detection scheme. The proposed work focuses on V-BLAST technique with a Multiple Input Multiple output (MIMO) technology followed by receiver detection techniques like Zero forcing (ZF), Minimum Mean Square Error (MMSE) with back substitution SIC (Symbol Interference Cancellation). The proposed methodology...
In this paper, we analyze the performance of cooperative diversity using adaptive Decode and Forward (DF) relaying over independent non identical flat composite fading channels which include multipath fading and shadowing simultaneously. We have considered the generalized-K model which is very versatile and accurately approximates many of the commonly used channel models as Nakagami-m, log-normal...
Multipath fading is inherent in wireless communication systems. Diversity is the techniques which takes the advantage of multipath and mitigate the effect of fading and increase signal strength. Space Time Block codes (STBC) are used in MIMO systems to improve the performance by maximizing transmit and/or receive diversity. Among different schemes based on STBC, Quasi orthogonal space time block code...
Instead of using eigen-beamforming approach to increase capacity gain, an optimal weight scheme is employed in the closed-loop multiple-input multiple-output (MIMO) orthogonal frequency division multiplexing (MIMO-OFDM) wireless system design. In particular, this scheme provides an uplink scale weight vector pre-weighting space-time block code (STBC) signals at each transmit sub-carrier in accordance...
Multi-user multi-input multi-output (multi-user MIMO) can increase the number of users simultaneously accessing the same base station (BS) without increasing the signal bandwidth. MIMO signal detection which can provide better bit error rate (BER) performance than linear detection with less computational complexity is indispensable in order to enhance the uplink cellular capacity of multi-user MIMO...
Relay networks achieve high performance by utilizing cooperation between nodes which can classified as multi-hop networks and cooperative MIMO relaying networks. Cooperative diversity is a transmission technique to overcome fading, multipath and inter-channel interference. As an important part of "spatial diversity" systems, cooperative diversity involving multi hop data relays is a solution...
The performance of spatial multiplexing-based multiple-input multiple output (MIMO) systems using zero forcing (ZF) detector in frequency selective fading channels is analyzed in this paper. The approximation of a linear combination of Wishart matrices is used to derive the probability density function (p.d.f.) of output signal-to-noise ratio (SNR) expression. Analytical error rate expressions for...
Generalized selective combining (GSC) is a hybrid diversity technique involving first selective combining (SC) followed by maximal ratio combining (MRC). In this paper we study a new technology based on bit log-likelihood ratio (BLLR) which is better than the traditional GSC based on signal-to-noise ratio (SNR) in performance. WCDMA is one of the key technologies of the third-generation mobile communication...
In recent years, MIMO MC-CDMA system was extensively studied, its uplink synchronization model using space-time block coding (STBC) is described in time-varying multi-path fading environment, a new multi-user detection algorithm based on MBER (minimum bit error rate) was proposed for it. The algorithm can be realized using kernel density estimation and gradient descent methods. Simulation results...
Transmission environment of mine laneway is non-free, wireless communication reliability is reduced by multi-path fading. MIMO can efficiently overcome multi-path fading, but MIMO channels in mine laneways have strong correlation. In this paper, the performances of space-time code in mine laneway are investigated, and the pair wise error probability (PEP) about mine laneway is analyzed. Following...
It has been shown that channel state information (CSI) at transmitter can significantly increase the performance of a relay system. However, most of the existing designs assume perfect CSI at the transmitters. Since most practical systems can only obtain partial CSI at the transmitters, it is necessary to analyze the relay channels with limited CSI feedback. Our objective in this paper is to find...
The long term evolution (LTE) standard for uplink transmission is based on single carrier frequency division multiple access (SC-FDMA) maintaining low peak-to-average power ratio (PAPR), which is very valuable for the practical handset design. Recently the usage of codebook-based precoding has been thoroughly discussed for the LTE-Advanced (LTE-A) uplink. Among the various precoding schemes, equal...
In this contribution, we examine the bit error rate (BER) performance of orthogonal space-time block codes (OSTBCs) under flat-fading channels with imperfect channel state information. We present new exact BER expressions for PAM and QAM signal constellations, regardless of the fading distribution. Furthermore, we show how these expressions can be efficiently and accurately evaluated for the case...
The performance of a wireless communication system is analyzed considering multi-carrier OFDM with Multiple- Input-Multiple-Output (MIMO) wireless channel and Space-Time Block Coding (STBC). Bit Error Rate (BER) expression for MIMO-OFDM system without and with STBC is presented considering fading and timing jitter with QPSK, DPSK and DQPSK modulation schemes. The performance results are evaluated...
In multi-antenna wireless communications, spatial and temporal correlations always affect the performance of space-time codes (STC) designed for uncorrelated channels. In this paper, we use the Laplace transform and derive a closed-form expression for pairwise error probability (PEP) of STC over this double correlated fading channels. Numerical results show that the simple expression can achieve the...
MIMO systems have been proved to improve communication in wireless systems but with increased system complexity. The increase in complexity is due to the increase in the number of radio frequency chains to be decoded at the receiver end. To try to address the problem of complexity associated with an increase in the number of antennas, antenna selection was proposed. For the purpose of this study transmit...
The traditional adaptive modulation and coding (AMC) scheme has been designed separately from higher protocol layers. In this paper, we consider the joint effects of finite-length buffer at the data link layer and the channel state information (CSI) at the physical layer for the adaptive transmission over the multiple input multiple output (MIMO) fading channel. A novel cross-layer adaptive transmission...
Distributed video coding (DVC) promises good quality with low complexity transmitters. However, previous research on DVC mostly focusses lossless channel, i.e., parity bit stream is not influenced by channel noise or distortion. This paper considers DVC over realistic wireless channel with noise and multipath fading. Note, errors in the parity bit will severely impair the system performance. We consider...
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