Achievable throughput in power-constrained cognitive wireless networks

Considering both spectrum underlay and opportunistic spectrum access scenarios in cognitive wireless networks, we seek to solve the following problem in this paper: Given that the secondary nodes have imposed upper limits on their transmission power levels to coexist with the primary network, what is the achievable throughput by the power-constrained secondary nodes? We first obtain statistics for some spatial properties in the secondary network, e.g., relative distances and angles between nodes. Assuming that the secondary transmitters choose the maximum permissible power level to coexist with a primary link and using the obtained spatial statistics, we find a lower bound for the throughput of secondary nodes by considering different forwarding models in the secondary network. We show that the approach is applicable for finding the achievable throughput in general power-constrained random wireless networks.