Mohammad Abu Hanif

Pilot-based channel estimation in two-way amplify-and-forward relay networks

In this paper, we propose a pilot based channel estimation technique in two-way relay networks. We propose to transmit a pilot symbol together with the data symbol during transmission. In absence of Channel State Information (CSI), destination uses the pilot symbol to estimate the channel. In this system, the relay amplifies the pilot and the data symbol then forward them to the destination using amplify and forward (AF) protocol. We assume that the relay gain is fixed, so the relay does not need to estimate the channel, the destination only estimate the channel. We apply well-known Least-square (LS) and minimum mean-square error (MMSE) channel estimation methods to estimate the channel.

A noble circularly symmetric Gaussian covariance matrix based channel estimation scheme for large-scale MIMO systems

With large-scale Multiple-input Multiple-output (MOMO), we think of a system that use antenna arrays with an order of magnitude more elements than in systems being built nowadays, say a hundred antennas or more. As it is known that, the more antennas the transmitter/receiver is equipped with, the more the possible signal paths, the better the performance in terms of data rate and link reliability. However, channel estimation in large-scale MIMO is said to be hampered by the pilot contamination effect, constitute a major reduction for overall system performance. In this paper, we present a novel approach which tackles this problem by enabling a covariance formulation between cells during the channel estimation phase itself, could leads to improver the system performance. Here we present a noble scheme title as large-scale MIMO channel estimation based on circularly symmetric Gaussian covariance matrix. The numerical result shows the significance of proposed scheme.

Analysis of a group decoding scheme for Double-ABBA Quasi-Orthogonal STC

In this paper we propose a system where we divide the group with 2 symbols. The two added symbols are separated by multiplexing and later added using the DE-multiplexing technique. In our propose system a simple Partial Interference Cancelation (PIC) group decoding scheme is used for Double-ABBA Quasi-Orthogonal Space Time Code, which reduces the decoding complexity for the higher order Multiple Input Multiple Output (MIMO) space time block coding.

Capacity Enhancement with Joint Precoding for Multiple-Input Multiple-Output Downlink System

Multiple antennas can provide huge capacity gains when the transmitter knows the channel state information (CSI). In multiple-input multiple- output (MIMO) wireless system, CSI at transmitter (CSIT) side can significantly improve system performance by increasing the transmission rate and enhancing reliability. Precoding is a technique that exploits CSIT by processing the signal before transmitting. In this paper, a new precoding scheme called hybrid multiple-input multiple-output precoding (HMP) is proposed. HMP is the combination of a linear and a nonlinear precoder. In HMP, nonlinear precoding in the good channel and linear precoding in the bad channel is used. The well-known Tomlinson-Harashima precoding (THP) is considered as nonlinear precoding. If number of transmit antennas is chosen less than or equal to four, HMP has no use, conventional antenna selection scheme would better perform. Therefore, for perform better at least four or more Tx antennas need to be chosen. The system achievable rate is calculated to show the performance of HMP scheme compared with the conventional scheme.

Sum-rate analysis of two-way multi-relay multi-user MIMO networks with two-hop precoding

In this paper, we study a joint source and relay pre-coding technique for multiuser multi-relay that help to maximize sum rate (SR) for Multiple-Input Multiple-Output (MIMO) link. Here we proposed two-hop precoding technique by implementing Zero-Forcing (ZF) as source precoder and Dirty Paper Coding (DPC) as relay precoder. We show performance by simulating and show that ZF-DPC (i.e., ZF at source and DPC at relay) technique help us to improve sum-rate than using ZF-ZF (i.e., ZF precoder at source and relay).

Blind Channel Estimation based on Hadamard Matrix Interstream Transmission for Multi-Cell MIMO Networks

In this paper, we introduce a Hadamard matrix interstream transmission based blind channel estimation for multi-cells multiple-input and multiple-output (MIMO) networks. The proposed scheme is based on a network with mobile stations (MS) which are deployed with multi cells. We assume that the MS have the signals from both cells. The signal from near cell are considered as desired signal and the signals from the other cells are interference signal. Since the channel is blind, so that we transmit Hadamard matrix pattern pilot stream to estimate the channel; that gives easier and fast channel estimation for large scale MIMO channel. The computation of Hadamard based system takes only complex additions, and thus the complexity of which is much lower than the scheme with Fourier transform since complex multiplications are not needed. The numerical analysis will give perfection of proposed channel estimation.

An efficient shared relay beamforming scheme for multi-cell multi-user LTE-A cooperative networks

The recent resurgence in interest in the small cells is being driven primarily by market demand for higher network capacity to host existing and new data services. Cell coverage continues to be an issue due to limited indoor penetration at higher transmission frequencies. For such cases, small cells are likely to play a vital role in providing indoor coverage and capacity. In this paper, we proposed a shared relay beamforming scheme for multi-user multi-cell (MCMU) cooperative networks. Here, the multi-cell shared a relay cell for cooperation. By doing so, the average throughput is increased. The simulation result shows the effectiveness of the proposed scheme.

Toeplitz channel matrix decomposition with vectorization for very large-scale MIMO

Due to enormous number of user and limited memory space, the memory savings is become an important issue for big data service these days. In the large scale multiple-input multiple-output(known as Massive MIMO) system, the Teoplitz channel can play the significance rule to improve the performance as well as power efficiency. In this paper, we propose a Toeplitz channel decomposition based on matrix vectorization. Here we use Toeplitz matrix to the channel for large scale MIMO system.

Interference Management Analysis of Double-ABBA and ABBA Quasi-Orthogonal Space Time Code

In this paper we show the performance of Double-ABBA and ABBA scheme in with an interference management technique. We propose a system with partially cancel the interference which reduce the decoding complexity for higher order Multiple Input Multiple Output (MIMO) system. This interference cancellation scheme is called as interference management scheme. Therefore we use a group decoding technique proposed by Guo and Xia which is known as Partial Interference Cancellation (PIC) group decoding for Double-ABBA and ABBA Quasi-Orthogonal Space Time Coding. Finally we compare the performance of ABBA and Double-ABBA schemes.

Capacity of the two-way relay channel based on pilot channel estimation

In this paper, we calculate the capacity region of a pilot based channel with estimation error in two-way relay networks. We propose to transmit a pilot symbol together with the data symbol during transmission. In absence of Channel State Information (CSI), destination uses the pilot symbol to estimate the channel. We apply well-known Least-square (LS) and minimum mean-square error (MMSE) channel estimation methods to estimate the channel. We also show that the proposed method may maximize the achievable rate with AF.