We apply the concept of artificial and controlled interference in a triangular relay network with an untrusted relay aiming at enhancing the wireless communication secrecy between the source and the destination node. In order to shield the square quadrature amplitude modulated (QAM) signals transmitted from the source node to the relay, the destination node designs and transmits artificial nois...

The secure wireless communication has been an important field of research. The proposed max-ratio relay selection techniques introduced to security of transmission in buffer aided cooperative wireless network. The data transmitted from source to relay and relay to destination. An eavesdropper can used to intercept the data from source to relay and relay to destination. Assume, data buffer are a...

In cooperative relay networks, the selected relay nodes have great impact on the system performance. In this paper, a multi-relay selection schemes that consider both single objective and multi-objective are proposed based on evolutionary algorithms. First, the single-objective optimization problems of the best cooperative relay nodes selection for signal-to-noise ratio (SNR) maximization or po...

In this paper, we propose a robust relay precoder in the multiple operator relay sharing system, where multiple base stations transmit to their target user terminals simultaneously with the assistance of an amplify-and-forward relay. The base stations and the user terminals are equipped with single antennas while the relay employs multiple antennas. The channel state information at the relay is...

Multi-hop relaying in cellular networks can greatly increase capacity and performance by exploiting the best available links to a base station. We envision an environment in which relay networks are dynamically formed when performance on the radio access network is degraded and then dissolved when the performance improves or the radio spectrum on which the relay network is operating is reclaime...

A discrete memoryless half-duplex relay channel is constructed from a broadcast channel from the source to the relay and destination and a multiple access channel from the source and relay to the destination. When the relay listens, the channel operates in the broadcast mode. The channel switches to the multiple access mode when the relay transmits. If the broadcast component channel is physica...

In cooperative relay networks, Channel State Information (CSI) is estimated at receiver. The estimated CSI is sent back to the relays through feedback link. This estimated CSI is often outdated due to feedback delay and the estimated outdated CSI is used for relay selection and detection which affects the performance of the system. The outage and error rate performance of the relay selection sc...

This paper presents the capacity of a modulo-sum simple relay network. In previous work related to this paper, capacity was characterized for the case where the noise was transmitted to the relay. And the closed-form capacity was derived only for the noise with a Bernoulli-( distribution. However, in this paper, the source is transmitted to the relay, and a more general case of noise with an ar...

Relay selection is an attractive method to improve the bandwidth efficiency of cooperative networks [1]-[3]. Specifically, Bletsas and others [1] proposed a distributed relay selection based on the channel information of both the first and second hops for each relay, showing that the diversitymultiplexing tradeoff of relay selection is identical with that of distributed space-time coding. Recen...

The Relay Nodes has become an important radio resource in next-generation wireless communication systems. The optimal number of RNs is one of the crucial issues in configuring a cost-effective RN-based network architecture. In this work, we present a modified relay based MAC protocol to describe the impact of the number of RNs on the Throughput, end-toend delay, PDR, Overhead of MAC Protocol ba...