Adaptive modulation and coding decision framework for SDRs

Abstract

Continuously altering wireless benchmarks and protocols have resulted in conscious shift in the direction of the programming methodology involved in designing / implementing new radio systems. This has led to a tremendous interest in Software Defined Radios (SDR). They offer flexibility in choosing economical modulation schemes and robust coding thereby enabling reliable communication. Modulation and demodulation techniques in digital signal processing are the key technology of the SDR implementation; therefore, researchers are probing into new avenues of these digital techniques through a variety of software platforms. GNU (GNU’s Not Unix) Radio is gratis / open source software which contains numerous signal processing building blocks available to realize wireless simulations based on software. Software radios provide a flexible mean to realize a lot of waveforms which can be deal with a single hardware platform by simply changing the programming / code. Adaptive modulation technique offers spectral efficiency for communication systems by adapting the modulation scheme in accordance with the instantaneous channel / wireless conditions, interference state and throughput or data rate needs. The adaptive structure helps in dynamically altering the communication method basing on the attributes of the arriving signal and characteristics of the propagation channel. This thesis presents a comprehensive framework for establishing and effectively operating an adaptive modulation / coding technique based on the wireless channel parameters. As a result of this framework our indigenous SDR development organizations may analyze and adapt their waveforms.