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I/Q imbalance, which is one of the radio frequency (RF) circuit impairments in direct conversion transmitter and receiver, introduces severe performance degradation in wireless communication systems. In this paper, we propose a novel blind compensation algorithm for both frequency-dependent and frequency-independent I/Q imbalance based on independent component analysis (ICA) in multiple input multiple...
We propose a genetic algorithm (GA) based equalization approach for direct sequence ultra-wideband (DS-UWB) wireless communications, where GA is combined with a RAKE receiver to combat the inter-symbol interference (ISI) due to the frequency selective nature of UWB channels for high data rate transmission. Simulation results show that the proposed GA based structure significantly outperforms the RAKE...
In this paper, we propose an enhanced greedy dynamic subcarrier allocation algorithm for single carrier frequency division multiple access (SC-FDMA) systems. This so called mean-enhanced greedy algorithm allocates subcarriers in a greedy fashion, based on the information of the users' subcarriers mean gains. We show through simulation results that the proposed algorithm outperforms the conventional...
We propose a non-redundant linear precoding scheme and three peak-to-average power ratio (PAPR) reduction schemes for multiple-input multiple-output (MIMO) orthogonal frequency division multiplexing (OFDM) systems with independent component analysis (ICA) based blind equalization. The proposed precoding at the transmitter allows complete elimination of the ambiguity in the ICA equalized signals under...
We propose an adaptive frequency-domain channel estimator based on Kalman smoothing for uplink multiple input multiple output (MIMO) orthogonal frequency division multiplexing access (OFDMA) systems. The application of Kalman smoothing in frequency-domain channel estimation results in a much lower computational complexity than time-domain estimation approaches. Channel interpolation is employed to...
We investigate the effects of two different scaling methods and two mutation types on the performance of a genetic algorithm (GA) based equalization approach for direct sequence Ultra-wideband (DS-UWB) wireless communications. Also, we use adaptive generation along with some other parameters to know their effects on the performance in comparison to a previous work, where GA is combined with a RAKE...
This paper investigates the effect of using different optimization criteria for dynamic subcarrier allocation in a single carrier - frequency division multiple access (SC-FDMA) system. Simulation results show that using the minimum bit error rate (BER) as the optimization criterion has the best BER performance and an almost optimal capacity performance. The other criteria referred to as maximum spectral...
Adaptive modulation schemes have been proposed to optimize Shannon's channel capacity in recent orthogonal frequency division multiplexing (OFDM) based broadband wireless standard proposals. By adapting the modulation type (effectively changing the number of bits per symbol) at the transmitter end one can improve the bit error rate (BER) during transmission at designated SNR. Blind detection of the...
The genetic algorithm (GA) is a well studied technique, which can obtain efficiently a near-optimal solution with much lower computational complexity compared to the maximum likelihood detection (MLD) approach. In overloaded MIMO systems, since the number of near equal-power co-channel interferers is higher than the number of receive antennas, the interference cannot be completely removed by spatial...
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