Distributed Algorithms for Spectrum Allocation, Power Control, Routing, and Congestion Control in Wireless Networks

We develop distributed algorithms to allocate resources in multi-hop wireless networks with the aim of minimizing total cost. In order to observe the fundamental duplexing constraint that co-located transmitters and receivers cannot operate simultaneously on the same frequency band, we first devise a spectrum allocation scheme that divides the whole spectrum into multiple sub-bands and activates conflict-free links on each sub-band. We show that the minimum number of required sub-bands grows asymptotically at a logarithmic rate with the chromatic number of network connectivity graph. A simple distributed and asynchronous algorithm is developed to feasibly activate links on the available sub-bands. Given a feasible spectrum allocation, we then design node-based distributed algorithms for optimally controlling the transmission powers on active links for each sub-band, jointly with traffic routes and user input rates in response to channel states and traffic demands. We show that under specified conditions, the algorithms asymptotically converge to the optimal operating point.Comment: 14 pages, 5 figures, submitted to IEEE/ACM Transactions on Networkin

Characterization of End-to-end Path Selection for Cognitive Radio Wireless Mesh Networks

Abstract: The Cognitive Radio (CR) can delivers the environment to Secondary Users (SUs) of Wireless Mesh Network (WMN) to utilize unused spectrum of Primary Users (PUs) opportunistically. The CR can improve the spectrum usage of the WMN. However, this rises the some additional complexities for the SUs such as spectrum heterogeneity, unpredictable PU activity and interference constraints. In this paper an analytical model has been developed to analyse these complexities for each SU node and link characteristics for end-to-end optimal Path and channel assignment. Numerical results show that the analytical model is an effective tool to investigate the effects of the PU activities and channel heterogeneity on the network performance