arXiv subjects

Md. Abdul Latif Sarker

Publications and source records attributed to Md. Abdul Latif Sarker.

6 recordsLinked to original sources

arXiv2021

Blockwise Phase Rotation-Aided Analog Transmit Beamforming for 5G mmWave Systems

In this letter, we propose a blockwise phase rotation-aided analog transmit beamforming (BPR-ATB) scheme to improve the spectral efficiency and the bit-error-rate (BER) performance in millimeter wave (mmWave) communication systems. Due to the phase angle optimization issues of the conventional analog beamforming, we design the BPR-ATB for reducing the rotated beamspace of the equivalent channel and improving the minimum Euclidean distance. To verify the effectiveness of the proposed BPR-ATB scheme, we employ an Alamouti coding technique at the transmitter and evaluate the bit-error-rate performance for mmWave multiple-input and single-output systems. The simulation results show that the proposed BPR-ATB scheme outperforms the conventional discrete Fourier transform-based ATB scheme.

cs.IT↗

arXiv2019

Rate-Loss Mitigation for a Millimeter-Wave Beamspace MIMO Lens Antenna Array System Using a Hybrid Beam-Selection Scheme

The rate loss is an important issue for multi-user beamspace multiple-input multiple-output (MIMO) millimeter-wave systems. In such systems, multi-cluster channel propagation leads as a function of the quantization error and, as a result, each active user suffers a significant rate loss. Particularly, a conventional single beam selection (SBS) scheme is used in an equivalent beamspace MIMO channel to reduce the required number of radio frequency (RF) chains, but this scheme does not properly mitigate the quantization error due to the limited number of the channel propagation clusters per-user. In addition, optimally selected beams or RF chains are operated at the same number of the precoded data streams. Consequently, each active user inherently loses a huge number of data streams utilizing the conventional SBS scheme. Therefore, we propose a hybrid beam selection (HBS) scheme in an equivalent beamspace MIMO channel to implement a multiple beam or RF chain group selection opportunity and choose a reliable channel propagation cluster per-active-user, which directly affects to mitigate the quantization error. The numerical result is verified by computer simulations in terms of a millimeter-wave MIMO downlink channel environment.

eess.SP↗

arXiv2018

Distortion-free Golden-Hadamard Codebook Design for MISO Systems

In this letter, a novel Golden-Hadamard codebook (GHC) scheme is proposed to improve the performance of the traditional precoded Alamouti coding for multiple-input and single-output systems. Although the traditional discrete Fourier transform codebook (DFTC) performs satisfactorily with Alamouti coding and offers numerous benefits for the Rayleigh fading channel, this scheme inherently generates huge codeword distortion, which leads to a lower minimum chordal distance (MCD). Furthermore, the uncertain format of all prior versions of codebooks results in poorer minimum determinant (MD) values. Hence, the proposed GHC scheme successfully deals with the issues of traditional DFTC to achieve a better codebook format that completely overcome both MCD and MD problems. The effectiveness of the proposed GHC scheme is confirmed, in terms of bit-error-rate through Monte Carlo simulations.

cs.IT↗

arXiv2016

A Unified Linear Precoding Design for Multi-user MIMO Systems

We address the problem of the bit error rate (BER) performance gap between the sub-optimal and optimal linear precoder (LP) for a multiuser (MU) multiple input and multiple output (MIMO) broadcast systems in this paper. Particularly, mobile users suffer noise enhancement effect due to a sub-optimal LP that can be suppressed by an optimal LP matrix. A sub-optimal LP matrix such as a linear zero-forcing (LZF) precoder performs in high signal to noise ratio (SNR) regime only, in contrast, an optimal precoder for instance a linear minimum mean-square-error (LMMSE) precoder outperforms in both low and high SNR scenarios. These kinds of precoder illustrates the BER gap distance at least 0.1 when it is used in itself in a MU MIMO systems. Thus, we propose and design a unified linear precoding (ULP) matrix using a precoding selection technique that combines the sub-optimal and optimal LP matrix for a multi-user MIMO systems to ensure zero BER performance gap in this paper. The numerical results show that our proposed ULP technique offers significant performance in both low and high SNR scenarios.

cs.IT↗

arXiv2016

Mean Capacity of Spatially Semi-Correlated MIMO Fading Channel

This study investigates the mean capacity of multiple-input multiple-output (MIMO) systems for spatially semi-correlated flat fading channels. In reality, the capacity degrades dramatic due to the channel covariance (CC) when correlations exist at the transmitter or receiver or on both sides. Most existing works have so far considered the traditional channel covariance matrices that have not been entirely constructed. Thus, we propose an iterative channel covariance (ICC) matrix using a matrix splitting (MS) technique with a guaranteed zero correlations coefficient in the case of the downlink correlated MIMO channel, to maximize the mean capacity. Our numerical results show that the proposed ICC method achieves the maximum channel gains with high signal-to-noise ratio (SNR) scenarios.

cs.IT↗

arXiv2016

An Error Covariance Splitting Technique for Multi-User MIMO Interference Environment

This paper investigates an error covariance matrix splitting technique for multiuser multiple input and multiple output (MIMO) interference downlink channel. Most of the related work has thus far considered the traditional error covariance matrix which has not been well-shaped for maximizing the system capacity. Thus, we split and propose a new iterative error covariance matrix to mitigate the system error and maximize the system capacity in this paper. Numerical results illustrate that our proposed method is strictly better than the traditional method.

cs.IT↗