Performance Characteristics Evaluation for Cooperative Communication

Wireless channels suffer severely from the effect of multi-path and fading. To mitigate these effects of fading and, cooperative diversity protocols are used. In cooperative diversity, two or more users share their antennas to create a virtual MIMO system. Hence in cooperative communication several single antenna relays assist the transmission between a source and a destination. In this work, cooperative communication protocols such as amplify and forward and decode and forward are simulated for relaying. The received signals at the destination are combined using various diversity combination protocols such as Maximal Ratio Combining (MRC) and Fixed Ratio Combining (FRC). For the performance study of cooperative communication protocol in wireless network, the symbol error rate (SER), outage probability and channel capacity are simulated for single relay and multiple relay in a flat fading Rayleigh channel.. In addition to this, for a 3 node cooperative communication containing a source , a relay and a destination the impact of relay location is studied for 3 different location of relay i.e. relay placed closer to the source, closer to the destination and at the midway between the source and the destination. When the relay is located in the middle of source and destination, it gives the best system performance. When the relay is located closer to the source, the quality of source-relay link is good, and the relay can decode the received information. On the other hand, when the relay node is located close to the destination, the system performance degrades. Through simulation results, it is shown the positive role that the relay plays, as it improves significantly the performance of the system and leads to lower SER and lower outage probability.