Interference Avoidance via Adaptive Wavelet Packet Modulation in Wireless Communication Systems

The proposal addresses the problem of adaptive modulation/demodulation scheme in the presence of interference for wireless communication systems. The objective is to develop a new class of communication system that is impervious to natural and man-made interferences. Here, motivated by the concept of software-defined radio, we propose an adaptive modulation/demodulation scheme which modifies the user's signature waveforms by maximizing the signal to interference ratio. Changing the transmitting signature waveform is one step beyond the existing adaptive modulation schemes where constellation size, transmission power, symbol time, and coding rate are adapted to the channel fading level. By maximizing the orthogonality between the transmitting signature waveform and the interference, a better and simpler detection can be achieved at the receiver. The idea of maximizing the orthogonality is achieved by representing the signature waveform using the least significant eigenfunction of the interference. There are two essential concepts behind our signature waveform adaptive scheme. Here, we proposed to integrate the basis selection strategy based on Wavelet Packet Analysis with the state-of-art interference avoidance algorithms. In this proposal, we will develop the mathematical foundation for adaptive signature waveform design and deliver the system architecture under the scenario of symbol-synchronous single-cell multi-user system.