Ripples in Communication

Abstract

Wavelet Packet Modulation (WPM) is a multi-carrier transmission technique that uses orthogonal wavelet packet bases to combine a collection of information bits into a single composite signal. This system can be considered as a viable alternative, for wide-band communication, to the popular Orthogonal Frequency DivisionMultiplexing (OFDM) system. The main advantage of WPM is that the transmission characteristics of the system can be adapted according to the radio environment to maximize resource utilization. The WPM is a system under development and has not been studied extensively. In this research work the operation of aWPMradio is successfully evaluated. The thesis primarily focuses on the question of how efficient and robust wireless radios can be designed with the aid of wavelet theory. To do so the challenges involved in the practical implementation of the system are evaluated and understood. Suitable mechanisms that address communication theory figure-of-merits such as Peak-to-average power ratio (PAPR), loss of time/phase/frequency synchronization, channel equalization are devised and tested. Furthermore, the advantages of the WPM system for wireless transmission are demonstrated in three scenarios,namely, 1. Wavelet packets for spectrum estimation. 2. Wavelet packets for dynamic spectrum access. 3. Design of new wavelets based on system requirements. The efficacy of the proposed algorithms is validated using computer simulations and numerical analysis. The results of the research show that the WPM is an effective addition to existing wireless transmission modes.