4 research outputs found
Performance Analysis of Output Threshold-Based Incremental Multiple-Relay Combining Scheme with Adaptive Modulation for Cooperative Networks
In this paper, we propose an output threshold-based incremental multiple-relay combining scheme for cooperative amplify-and-forward relay networks with nonidentically distributed relay channels. Specifically, in order to achieve the required performance, we consider both conventional incremental relaying and multiple-relay selection where relays are adaptively selected based on a predetermined output threshold. Moreover, the adaptive modulation technique is adopted by our proposed scheme for satisfying both the spectral efficiency and the required error rate. For the proposed scheme, we first derive an upper bound of the output combined signal-to-noise ratio and then provide its statistics such as cumulative distribution function (CDF), probability density function (PDF), and moment generating function (MGF) over independent, nonidentically distributed Rayleigh fading channels. Additionally, we analyze the system performance in terms of average spectral efficiency, average bit error rate, outage probability, and system complexity. Finally, numerical examples show that our proposed scheme leads to a certain performance improvement in the cooperative networks
Threshold-Based Relay Selection for Cooperative Wireless Network
Cooperative communication plays a vital role in the wireless domain recently due to its
numerous benefits such as coverage extension, improvement in spectral efficiency, and
throughput by increasing the complexity of the system. Furthermore, security becomes a key
issue for implementing a cooperative communication system.
In this thesis, the complexity is reduced by employing differential modulation as they do not
require complete channel state information (CSI). Different threshold-based relay selection
schemes are also proposed to reduce complexity. Furthermore, the security issue in the
cooperative wireless network is addressed by enhancing the physical layer security using the
proposed double threshold-based optimal relay selection scheme