Hardware implementation of multiband and multimode modem for software defined radio/ cognitive radio

Abstract

Present day programmable hardware and SDR (Software Defined Radio) have enabled radio processing to switch from analog to digital. The work presented here describes a method of designing a multiband & multimode modulator for SDR/ CR (Cognitive Radio) and its implementation on programmable hardware, such as FPGA (Field Programmable Gate Array). SDR has become a most important topic of research in the field of satellite communication. The prototype presented here shows ability to dynamically alter modulation and demodulation scheme in a Satellite Communication (Satcom) terminal to suit given conditional requirements. The Cognitive module will decide which modulation scheme and frequency band has to be used for signal transmission. Cognitive module provides control bit to select the modulation scheme and operating frequency. The work presented here demonstrates a practical design and implementation procedure for modem used in SDR/ CR platform and gives detailed description of the baseband signal processing logic design in the FPGA.