The Optimal Receiving Signal Strength to Use the Relay Node in Wireless Network

The connectivity in wireless communication is established based on the receiving signal strength, which is affected by distance, interference, noise, mobility, etc. As a result, a node has a limited coverage area and generally 250m of communication range is assumed for free space environment in MANETs. Therefore, the connectivity becomes one of the significant limitations in deploying wireless networks such as MANETs, cellular, or Wi-Fi. The relaying concept was introduced, which places the additional node between out of range nodes, to overcome the coverage limitation. Therefore, the relay node became one of the solution to improve the connectivity in wireless network and many researchers tried to find the optimal location of the relay node to improve the overall performance. However, only low or no connectivity areas are considered to add the relay node in their study. The effectiveness of relay node for the nodes with the connectivity has not been investigated at the best of our knowledge. In this paper, we investigate the effectiveness of relay node through the experiment. Two protocols, TCP and UDP, are selected for the evaluation of the network performance using throughput, packet loss, and retransmission rate in various receiving signal strength with and without relay node. The results are presented, compared, and analyzed to identify the optimal condition in terms of receiving signal strength for addition of relay node to improve the performance between pair of nodes.