Underlay multi-hop cognitive networks with orthogonal access

Stochastic algorithms to allocate resources across different layers in an underlay multi-hop cognitive radio with primary and secondary users are presented. The algorithms aim to maximize the utility of the secondary users, while adhering to average interfering power constraints and accounting for the presence of imperfections in the state information. Interference among secondary users is modeled using a binary conflict graph, so that close-by secondary devices cannot transmit simultaneously. The optimal resource allocation dictates the power transmitted by each user, the rates at the transport, network and physical level, and the links to be activated. The design is casted as a nonlinear constrained optimization, and the solution is obtained using stochastic dual decomposition. Nu- merical experiments validate the theoretical claims.