MIMO-OFDM based Cognitive Radio Systems with Imperfect Spectrum Sensing by Multi-objective Optimization technique
B. Shiva Rani, Bodapati Venkata Rajanna · IJITR International Journal of Innovative Technology and Research - IJITR International Journal of Innovative Technology and Research · 2016
This paper presents optimization strategies for a MIMO (Multiple Input Multiple Output) OFDM (Orthogonal Frequency Division Multiplexing) based cognitive radio (CR) system. The proposed optimization schemes maximize the downlink transmission rate of the CR users under spatial interference constraints, considering both the availability and absence of the primary user (PU) Channel State Information (CSI). A multi-objective optimization (MOOP) approach to investigate the optimal link adaptation problem of MIMO OFDM based cognitive radio (CR) systems, where secondary users (SUs) can opportunistically access the spectrum of primary users (PUs). For such a scenario, we solve the problem of jointly maximizing the CR system throughput and minimizing it’s transmitting power, subject to constraints on both SU and PUs. The optimization problem imposes predefined interference thresholds for the PUs, guarantees the SU quality of service in terms of a maximum bit-error-rate (BER). Additionally, the results show that the performance of the proposed algorithm approaches that of an exhaustive search for the discrete optimal allocations with a significantly reduced computational effort. Simulation results presented validate the performance of the proposed schemes.