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In the Multiple Input Multiple Output (MIMO) systems, the receiver performance is greatly affected by Antenna Gain Imbalance (AGI). This paper proposes an novel AGI detection algorithm based on the Least Square (LS) channel estimation. The AGI parameter is accurately obtained after eliminating the influence of noise from the channel through the long-term statistics. Moreover, a compensation algorithm...
Here we have presented an alternate ANN structure called functional link ANN (FLANN) for channel equalization. In contrast to a feed forward ANN structure i.e. a multilayer perceptron (MLP), the FLANN is basically a single layer structure in which non-linearity is introduced by enhancing the input pattern with nonlinear function expansion. A novel method of training the FLANNs using PSO Algorithm...
In this paper, we investigate the outage performance of decode-and-forward (DF) based opportunistic cooperative communications with channel estimation errors at the receivers under Rayleigh fading channels, in which the effect of the direct link has been explicitly evaluated. To be specific, the exact expression of outage probability has been derived for arbitrary values of signal-to-noise ratio (SNR)...
The mobile WiMAX standard (802.16e) uses multiple-input multiple-output (MIMO) limited feedback linear precoding to exploit the channel state information at the transmitter. Although the performance of limited feedback linear precoding in relation to traditional open-loop MIMO-OFDM has been extensively studied in the literature, these studies commonly assume perfect channel estimation at the receiver...
In this paper, we propose an iterative SIC receiver architecture with pilot- and data-based channel estimation for efficient decoding of non-orthogonal superimposed signals. The non-orthogonal superposition concept on top of OFDMA is a promising technique to improve cell spectral efficiency. In the cellular case, where users with significant path loss are superimposed by an intelligent scheduler,...
For multiple-input multiple-output (MIMO) wireless communication system with minimum mean square error (MMSE) detection, power allocation between pilot and data symbols is investigated under MMSE channel estimation in this paper. We first propose a novel soft-output MMSE MIMO detector by taking the channel estimation error into consideration. Then, by random matrix theorem, we propose an effective...
A crucial parameter required for adaptive transmission in orthogonal frequency division multiplexing (OFDM) systems is the signal-to-noise ratio (SNR). In this paper, certain modifications to previously proposed preamble-based SNR estimator for wireless OFDM systems are suggested in order to improve estimation performance. Proposed modifications, related to DFT interpolation, are based on the adaptive...
We report on field trials using CoMP transmission in the downlink of a mobile radio network. Two new features enable over-the-air CoMP transmission from physically separated base stations and terminals. These are distributed synchronization and a fast virtual local area network. Using VLAN tags, terminals feed back the multi-cell channel state information to their serving bases where it is multiplexed...
Compared with the global positioning system (GPS), the digital television (DTV) broadcasting signal is a promising candidate for position location due to low implementation cost and strong signal reception. Without changing the current infrastructure of the Chinese DTV broadcasting network, this paper proposes a novel positioning scheme using the multi-carrier pseudo-noise (PN-MC) training sequence...
We consider a point-to-point, correlated and block fading multiple antenna channel where the receiver has a noisy channel estimation and the transmitter has the statistics of the channel. Although very high rates are promised when the receiver knows the channel perfectly, the capacity is not known when the receiver has a noisy channel estimation. In this paper, we will derive an upper bound to the...
Cooperative decoding is powerful technique for establishing good quality TV broadcasting. In cooperative decoding, some TV receivers, nodes, are cooperated, each other. These share the received information signal and thus obtain good quality information signal. Incremental-Maximum Ratio Combining (I-MRC) is one of the cooperative decoding methods. In I-MRC, the best condition's node and second one...
In wireless environment, the channels are really affected by a number of factors such as: fading, interference, noise. In most of wireless communications, we have applied the training sequences as known signal at the receiver for estimating the channel as well as the transmitted signal. Nowadays, many paid services in the entertainment industry have required the high security for their data and this...
Channel coherence time is commonly used to characterize the rate at which the channel changes. The recently introduced effective coherence time measures the channel change rate from an estimation perspective. It was shown that the effective coherence time is related to the capacity of the non-coherent channel, in which the receiver has no prior knowledge of the channel, and tries to estimate it from...
We propose advanced compressive estimators of doubly dispersive channels within multicarrier communication systems (including classical OFDM systems). The performance of compressive channel estimation has been shown to be limited by leakage components impairing the channel's effective delay-Doppler sparsity. We demonstrate a group sparse structure of these leakage components and apply recently proposed...
In this paper we analyze the sum rate of zero-forcing (ZF) precoding in MISO broadcast channels with limited feedback, transmit correlation and path loss. Our analysis assumes that the number of transmit antennas M and the number of users K are large, while their ratio remains bounded. By applying recent results from random matrix theory we derive a deterministic equivalent of the signal-to-interference...
Adaptive modulation and power allocation schemes have been widely used in multiple-input multiple-output (MIMO) systems to enhance spectral efficiency while maintaining bit error ratio (BER) to a target level. We derive the spectral efficiency of orthogonal space-time block codes (OSTBC) that can be achieved by applying adaptive modulation and power allocation. Compared to non-adaptive power scheme,...
Adaptive modulation and code (AMC) in Orthogonal Frequency Division Multiplexing (OFDM) is a promising approach to achieve higher data rates with sufficient performance. However a measure of channel state is desired in order to decide upon transition rates and modulation mode. SNR is such a sufficient measure. In this work, a channel estimator based on transform domain algorithm (TFD) is presented...
In this paper, we consider a multi-input multioutput (MIMO) two-way wireless relay network in which two users, U1 and U2, exchange their information via a relay station, R. Single carrier cyclic prefix (SCCP) is used in the system to combat intersymbol interference (ISI) in frequency-selective fading channels. The transmission process is divided into two phases. At phase 1, both users send their information...
This paper examines ways of improving channel estimation using successive decoding for the time varying frequency selective fading channel in a point to point wireless communication system. The channel state information (CSI) is not known a priori at either the transmitter or the receiver. The paper first presents the conventional pilot-symbol aided channel estimation (PACE) scheme and then the sequential...
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