A multiuser radio resource allocation scheme for spectrum efficiency maximization in cognitive OFDM ultra wideband radio systems

This paper presents a novel multiuser radio resource allocation scheme for spectrum efficiency maximization in the cognitive OFDM ultra wideband radio systems. We formulate the spectrum efficiency maximization as an NP-hard multidimensional knapsack problem, and we solve the problem by proposing a best-in-greedy approximation algorithm. The proposed approximation algorithm can optimally distribute the radio spectrum, transmitted power and data bits among different cognitive UWB nodes while guaranteeing the aggregate interference power from the UWB nodes to the primary wireless systems is below a certain threshold. A new expression of the aggregate interference power is derived by using the Fenton-Wilkinson method. The performance of the resource allocation scheme is analyzed over the UWB multipath channel models. The results show that the proposed scheme can maximize the spectrum efficiency and is with low complexity.