Multi-objective optimization route selection and resource allocation in wireless multi-hop cooperative cognitive radio sensor networks based on OFDMA

Abstract

Following spectrum constraints cognitive radio is introduced, as a technology to eliminate the imbalance between the lack of spectrum and unused spectrum. On the other hand, use of sensors also become more widespread, as in the near future will be an integral part of human life. So network topology in this paper is based on a Wireless Multi-Hop cooperative Cognitive Radio Sensor Networks based on OFDMA. in the objective of optimizing different types of end-to-end performance. Aiming to solve it optimally, we first show that this problem of optimal resource allocation and hopes can be formulated as a convex optimization problem and identify its necessary and sufficient conditions. Based on this conclusion, KKT conditions apply to the issue and the optimal solution can be found at any phase. we propose fmincon function in MATLAB that uses Lagrangian duality theory. The scheme thus converges to a globally optimal solution. Resource allocation and route selection is formulated as a multi-objective optimization problem. that one of its objectives is to find the optimal amount of hops and the second is considered to maximize the data transfer rate.also the effect of Interference Temperature constraints is reviewed.