Optmized Software Defined Radio

A software radio is a radio whose channel modulation waveforms are defined in software. A software radio receiver is an embedded platform that can support different communication standards. All the base-band processing is performed on a DSP. On the receiver side, the base-band processing encompasses matched filtering of the incoming data, frame synchronization, frequency offset and phase offset correction, timing offset correction and finally the demodulation of the digital base-band signal. For the system in consideration, the base-band processing is done on a TI DSP (TMSC6701), a DSP with stringent speed and memory constraints. For the software radio to function in real-time, it is imperative that each of the software components be highly optimized for time and space. This paper focuses on optimizing the three core modules of a software radio: filtering, correlation and frequency offset correction. A variety of optimization techniques such as Karatsuba, rhombing and overlap add using Spiral FFTs were employed to optimize the software components mentioned above. We managed to achieve a speed of 5X by employing the above-mentioned optimizations. We conclude on the basis of our timing results and analysis that a real-time implementation of our software defined setup is achievable.