Efficient relay selection scheme using regenerative and degenerative protocols for 5th generation WiMAX systems

Abstract

The major concerns for the 5th generation wireless systems are to provide higher data rates and higher transmission quality in the wireless network environment. Cooperative relaying as a promising technology has widespread attention, since it can achieve higher transmission quality and throughput for wireless networks. This paper aims at maximizing throughput and transmission quality by minimizing frame error rate (FER) as minimum as possible. Relay selection is an effective technique to improve the system performance in wireless networks by allowing users to cooperate with each other in their transmissions to achieve high transmission quality and diversity. This paper proposes an efficient relay selection scheme for WiMAX network with selection combining technique using amplify and forward and decode and forward protocols by analyzing the FER. FER approximation model based on improved signal to noise ratio was developed. In the proposed relay model, signals at the receiver are combined using selection combining technique. In maximum ratio combining (MRC) based cooperative relay systems, only the correctly detected signal will be forwarded by the relay and the performance will be worse under poor channel conditions. So the relay selection is done with selection combining technique. Simulation results exhibit the effectiveness of two relaying protocols amplify and forward (AF) and decode and forward (DF) individually and at high signal to noise ratio (SNR) region FER has been reduced in DF protocol than AF protocol. Based on the suppression of noise and effective retrieval of information, DF protocol is found to be more effective compared to AF protocol. The proposed structure is evaluated using performance parameters such as FER and SNR. Structural realization and analysis pertaining to Power and Throughput are implemented in MATLAB. Power allocation for water filling, optimal and sub optimal algorithms are analyzed for various channels. Simulation results have proven that suboptimal algorithm performs closer to optimal algorithm and water filling power allocation scheme outperforms both optimal and suboptimal scheme. High throughput is obtained by reducing the FER in DF protocol compared to AF protocol that improves the transmission quality of WiMAX networks. A throughput greater than 9.5Gbps can be achieved using DF protocol which increases the speed of 5G network up to 10Gbps.