Dual Hop Relay with Cooperative Diversity and Relay Selection

As wireless communication becomes more prevalent, the demand for higher data rates and uninterrupted connectivity is increasing. Future wireless systems are provisioned to be highly heterogeneous and interconnected. On one side, wireless ad hoc networks are emerging for a wide range of new applications, on the other side; infrastructure based broadband wireless systems are expanding to provide increasing number of services with ubiquitous coverage. Space-time coding is a MIMO technique which is well known for its ability to combat fading, increased system performance and capacity. Space time coding uses specially designed code matrix which enhance overall system performance than single antenna systems. Furthermore cooperative communication can benefit single antenna systems with the benefits of MIMO systems. Conjunction of cooperative communication with space time coding can provide capabilities to mitigate fading with increased system performance to a single antenna system. In this regard, this research work is focused towards the performance evaluation and enhancement of dual hop cooperative communication network with regenerative and non-regenerative relaying techniques. Log-likelihood ratio (LLR) based relay selection scheme is applied to cooperative diversity architecture and Bit Error Rate (BER) performance is compared with random, max-min and harmonic mean based relay selection schemes. Simulation of this research work is carried out on MATLAB 2010a, simulation results shows that application of diversity in cooperative communication networks enhance system performance by 12dB. Furthermore, LLR relay selection strategy enhance this performance by 4dB more. KeywordsCooperative Diversity, CooperativeSTBC, LLR Relay selection