Cognitive Radio Relay Network Performance Analysis by using Game Theory

Cognitive radio plays a vital role in wireless communication system. The cognitive radio consists of a transceiver which is used to check the availability of channel for communication and avoids busy channels by shifting into a unused channel. The scope for spectrum availability and area of coverage is increased by using cognitive radio. In cooperative cognitive relay network the primary traffic the primary users (PUs) will nominate some of the secondary users (SUs) as a relay. To make the secondary users co-operate with the primary user, primary user have to allocate some channel to the secondary user for data transmission. This significantly reduces the performance of the primary users and secondary users. Therefore, performance can be significantly increased by using MIMO in co-operative cognitive radio. By using beam forming technique in spatial domain over the multiple inputs multiple output antenna permits multiple data streams and suppression of interference. Using Nash Equilibrium (NE) to control the power among SUs, the PUs utilities and SUs utilities are obtained in MIMO-CCRN. By using MIMO technique the secondary users can co-operatively relay the data for the primary users while concurrently accessing the same channel to transmit its data. Time domain and spatial domains are examined to improve the efficiency of the spectrum for arranging the MIMO co-operative cognitive radio networks. DOI: 10.17762/ijritcc2321-8169.16043

Whale Optimization Algorithm for Transmit Antenna Selection in MIMO Cognitive Radio Systems

For performance enhancement of wireless communication systems, MIMO systems are used and have become an essential component of modern wireless communication networks. Different types of MIMO systems are used according to the application such as massive MIMO (mMIMO), millimeter wave MIMO (mmWave MIMO), distributed MIMO (D-MIMO), cooperative MIMO such as cognitive radio based MIMO, etc. In this paper, Whale Optimization Algorithm (WOA), a metaheuristic technique is used for solving the optimization problem of performing transmit antenna selection (TAS) i.e.,  selecting the best set of antennas at transmitter side for an overlay cognitive radio (CR) based hybrid MIMO system. Due to their capacity to intelligently utilise the priceless electromagnetic spectrum, CR communication systems prove to be an effective strategy for current and future wireless communication networks. The  Bit Error Rate (BER) versus Signal to Noise Ratio (SNR) graphs show the results of the proposed network

Cognitive MIMO Radio: A Competitive Optimality Design Based on Subspace Projections

Cognitive MIMO Radio: A Competitive Optimality Design Based on Subspace Projection

A General MIMO Framework for NOMA Downlink and Uplink Transmission Based on Signal Alignment

The application of multiple-input multiple-output (MIMO) techniques to non-orthogonal multiple access (NOMA) systems is important to enhance the performance gains of NOMA. In this paper, a novel MIMO-NOMA framework for downlink and uplink transmission is proposed by applying the concept of signal alignment. By using stochastic geometry, closed-form analytical results are developed to facilitate the performance evaluation of the proposed framework for randomly deployed users and interferers. The impact of different power allocation strategies, such as fixed power allocation and cognitive radio inspired power allocation, on the performance of MIMO-NOMA is also investigated. Computer simulation results are provided to demonstrate the performance of the proposed framework and the accuracy of the developed analytical results

On the Capacity of a Class of MIMO Cognitive Radios

Cognitive radios have been studied recently as a means to utilize spectrum in a more efficient manner. This paper focuses on the fundamental limits of operation of a MIMO cognitive radio network with a single licensed user and a single cognitive user. The channel setting is equivalent to an interference channel with degraded message sets (with the cognitive user having access to the licensed user's message). An achievable region and an outer bound is derived for such a network setting. It is shown that under certain conditions, the achievable region is optimal for a portion of the capacity region that includes sum capacity.Comment: 13 pages, 8 figures, Accepted for publication in Journal of Selected Topics in Signal Processing (JSTSP) - Special Issue on Dynamic Spectrum Acces

Some MIMO applications in cognitive radio networks

In the last decade, the wireless communication technology has witnessed a rapid development, which led to a rapid growth in wireless applications and services. However, the radio spectrum resources scarcity resulting from using the traditional methods of fixed spectrum resources allocation has potential constraints on this wireless services rapid growth. Consequently, cognitive radio has been emerged as a possible solution for alleviating this spectrum scarcity problem by employing dynamic resource allocation strategies in order to utilize the available spectrum in a more efficient way so that finding opportunities for new wireless application services could be achieved. In cognitive radio networks, the radio spectrum resources utilization is improved by allowing unlicensed users, known as secondary users, to share the spectrum with licensed users, known as primary users, as long as this sharing do not induce harmful interference on the primary users, which completely entitled to utilize the spectrum. Motivated by MIMO techniques that have been used in practical systems as a means for high data rate transmission and a source for spatial diversity, and by its ease implementation with OFDM, different issues in multi-user MIMO (MU-MIMO) in both the uplink and downlink in the context of cognitive radio are studied in this thesis. More specifically, in the first thrust of this thesis, the spectrum spatial holes which could exist in an uplink MU-MIMO cell as a result of the possible free spatial dimensions resulted from the sparse activity of the primary users is studied; a modified sensing algorithm for these spectrum spatial holes that exploit both the block structure of the OFDM signals and the correlation of their activity states along time are proposed. The second thrust is concerned with cognitive radio relaying in the physical layer where the cognitive radio base station (CBS) relays the PU signal while transmitting its own signals to its SUs. We define secondary users with different priorities (different quality of service requirements); the different levels of priority for SUs are achieved by a newly proposed simple linear scheme based on zero forcing called Hierarchal Priority Zero Forcing scheme HPZF

How to Understand LMMSE Transceiver Design for MIMO Systems From Quadratic Matrix Programming

In this paper, a unified linear minimum mean-square-error (LMMSE) transceiver design framework is investigated, which is suitable for a wide range of wireless systems. The unified design is based on an elegant and powerful mathematical programming technology termed as quadratic matrix programming (QMP). Based on QMP it can be observed that for different wireless systems, there are certain common characteristics which can be exploited to design LMMSE transceivers e.g., the quadratic forms. It is also discovered that evolving from a point-to-point MIMO system to various advanced wireless systems such as multi-cell coordinated systems, multi-user MIMO systems, MIMO cognitive radio systems, amplify-and-forward MIMO relaying systems and so on, the quadratic nature is always kept and the LMMSE transceiver designs can always be carried out via iteratively solving a number of QMP problems. A comprehensive framework on how to solve QMP problems is also given. The work presented in this paper is likely to be the first shoot for the transceiver design for the future ever-changing wireless systems.Comment: 31 pages, 4 figures, Accepted by IET Communication