To Cooperate or Not to Cooperate: An Outage Analysis of Interference-Limited Wireless Networks

Cooperative communication is an effective technique which provides diversity gains to combat the attenuation of radio signals caused by fading and path loss. By sharing each cooperative node´s antenna to form a virtual antenna array, the reliability of the wireless transmission can be significantly improved. On the other hand, cooperation among different nodes may produce a higher level of interference and degrade the overall performance of larger and dynamic networks with multiple concurrent transmissions. For practical environments, it is essential to investigate the tradeoff between cooperative diversity and this additional interference. In this paper, by analyzing and comparing the outage performance of non-cooperative and cooperative strategies, we derive a criterion which determines whether we should implement cooperation or not. Both analytical results and simulations show that a cooperative strategy is preferred for sparse networks. As the wireless network becomes more dense, the diversity gain is eventually eliminated by the excessive amount of interference, which implies that non-cooperative strategies should be used.