Indian Journal of Science and Technology

Abstract

Background/Objectives: Cognitive radio is used as promising technologies for dynamic spectrum access and optimization of wireless resources. Under dynamic spectrum access to provide the ability of working any band of frequency based on need, the reconfigurable cognitive radio is designed. Methods/Statistical Analysis: Multicarrier modulation is the feasible method to share the spectrum without interference. OFDM is one of the efficient multicarrier techniques available for the system design. One of the problems in OFDM for spectral sharing is the side band leakage that will inject interference from secondary radio sub carrier to primary radio sub carrier. To avoid this, in this work a Filter Bank based Multi Carrier (FBMC) modulation is used. Findings: Few simulation works are reported for the interference free spectrum sharing by using FBMC. But this work analyzes the real time practical implementation of the interference free dynamic spectrum sharing. Reconfigurable is another important aspect of the implementation which is provided by the Kintex 7 FPGA implementation of the reconfigurable filter bank multicarrier modulation using NI USRP 2943R SDR platform. This FBMC based Transceiver is implemented by using fast Xilink IP cores of FFT and systolic array based FIR filter IP core. The transceiver is realized to produce output for every clock after a fixed latency 240 clocks or 6 microsecond for 40Mz clock rate. This performance is achieved using single clock loop architecture of LABVIEW FPGA tool and the parallel, pipelined architecture realization of IP cores and other building blocks. Applications/Improvements: Experimental study shows that the BER of primary user for the implemented system is better than the OFDM system by the factor of 10-1.

Keywords: Cognitive Radio, Dynamic Spectrum Sharing, Multi Carrier Modulation, OFDM Reconfigurable, SDR