With the advent of IMT-Advanced, for the first time the target throughput obtained from wireless networks became comparable with wired counterparts. LTE and WiMAX have been the two main standards developed by 3GPP. The need to enhance the LTE and WiMAX has been driven by demand for higher spectral resources by the smart wireless devices in place of conventional phones. This transition from LTE ...

In this paper, an analysis of radar range and probability of detection by the use of multiple-input multiple-output (MIMO) radar with cooperative high altitude aeronautical platforms (HAAP) relay (which could operate at stratospheric altitudes) is presented. In this study, a method of cooperative diversity known as ampliy-and-forward (AF) is considered and a target fluctuation model (Swerling I...

Nowadays, providing higher data rate is a momentous goal for wireless communications systems. Interference is one of the important obstacles to reach this purpose. Interference alignment is a management technique that align interference from other transmitters in the least possible dimension subspace at each receiver and as a result, provide the remaining dimensions for free interference signal...

In this study, the minimum number of antennas at each user is derived to obtain 2M degrees of freedom (DOF) in the M × 1 ×M multiple-input–multiple-output (MIMO) multi-user two-way relay X channels. Based on the design of beamforming vectors for the conventional signal space alignment scheme, it is shown that each user needs at least ⌈M − (M/2)⌉ antennas to obtain DOF 2M with the relay having M...

In this paper, we investigate a joint source and relay precoding design scheme for an amplify-and-forward (AF) multiple-input multiple-output (MIMO) relay system with absence of the direct link. The joint optimization problem, which is to minimize an objective function based on the mean square error (MSE), is formulated as a nonconvex optimization problem in the AF MIMO relay system. Instead of...

Unified performance analysis is carried out for amplify-and-forward (AF) multiple-input-multipleoutput (MIMO) beamforming (BF) two-way relay networks in Rayleigh fading with five different relaying protocols including two novel protocols for better performance. As a result, a novel closedform sum-bit error rate (BER) expression is presented in a unified expression for all protocols. A new close...

This paper considers a decode-and-forward (DF) multi-way massive multiple-input multiple-output (MIMO) relay system where many users exchange their data with the aid of a relay station equipped with a massive antenna array. We propose a new transmission protocol which leverages successive cancelation decoding and zero-forcing (ZF) at the users. By using properties of massive MIMO, a tight analy...

In multi-hop communication systems, two-way relaying is one of the solutions to mitigate the spectral efficiency loss caused by a half-duplex transmission. In this paper, a simple two-way relaying scheme is proposed for two-hop two-user multiple input multiple output (MIMO) systems. In the proposed system, a base station and a relay station (RS), both equipped with two antennas, form a point-to...