Efficient Mutual Interference Minimization and Power Allocation for OFDM-Based Cognitive Radio

The ever-increasing demand for precious radio spectrum along with the inefficient usage of licensed band has led to the advent of the cognitive radio (CR) technology, which aims to provide opportunistic spectrum usage to unlicensed users and thus lead to the co-existence and interference control problem among heterogeneous systems. In this paper, an interference minimization and subcarrier power allocation approach for orthogonal frequency division multiplexing (OFDM)-based cognitive network is proposed. A transmission power negotiation signaling between CR transmitter and receiver is established through the use of encoded cyclic prefix (CP). Therefore, mutual interference to primary and other cognitive users can be minimized with reduced unnecessary transmission power. In addition, system performance of the receiver can be guaranteed in the process of mutual interference minimization. Beside this, subcarrier power allocation profile can be chosen from a set of predefined profiles and can be sent at the same time without additional signaling link and extra delay to the network. The transceiver structure and control signal encoding and decoding algorithm are investigated. The performance of the proposed signaling links are also analyzed and evaluated through simulations in different channel scenarios. In addition, interference minimization technique is validated through the simulation of probability density function (PDF) and then in a cognitive radio network with randomly distributed nodes to assess the overall perceived interference.