Enabling coexistence of cognitive vehicular networks and IEEE 802.22 networks via optimal resource allocation

Many studies show that the Dedicated Short Range Communication band is insufficient to carry increasing wireless data traffic in vehicular networks. The release of large TV spectra by FCC for cognitive access provides additional spectrum resources to solve the spectrum scarcity problem. However, FCC allows fixed devices to use high transmitting powers, while requiring portable devices to use significantly lower powers. This power asymmetry policy leads to a challenging coexistence environment for portable (e.g., vehicular) and fixed (e.g., IEEE 802.22) networks. In this paper, we address the coexistence problem between vehicular and 802.22 networks via resource allocation. We show that the problem is an NP-hard mixed-integer nonlinear programming problem, to which we propose two algorithms. First, we convert it to a convex programming problem, and propose a near-optimal primal-dual algorithm. Next, we reformulate the problem as a packing problem, and present a constant-factor approximation algorithm. Finally, we evaluate the algorithms through numerical examples.