Transmission Throughput of Decentralized Overlaid Networks with Outage Constraints

Overlaid networks, typically composed of primary and secondary networks, are emerging as a viable candidate to resolve the conflict between increasing demand for spectrum and spectrum shortage. The essential purpose of overlaid networks is to improve the network spectrum efficiency, which, however, may not be achieved if the secondary network is inappropriately configured. In decentralized overlaid networks, the throughput of the primary network will decrease due to the extra interference from the secondary network, and its loss may not be compensated by the throughput gained by the secondary network. This motivates us to study the overall throughput of the overlaid networks. In particular, we examine the overall transmission throughput, which is a variation of the transmission capacity, a popular metric in the study of decentralized networks. Our study provides a sufficient condition for the secondary network setting such that the overall throughput is improved over that of a stand-alone primary network. In addition both the maximal allowable secondary density and the optimal secondary density which maximizes the overall throughput are derived.