Waveform and Transceiver Designs for Smart Radio.

摘要

Utilizing multidimensional signaling techniques, a generalized multirate wavelet-based modulation format for orthogonally multiplexed communication systems is presented. Wavelet Packet Modulation (WPM) employs the basis functions from an arbitrary pruning of a dyadic tree structured filter bank as orthogonal pulse shapes for conventional Quadrature Amplitude Modulation (QAM) symbols. This generalized framework affords an entire library of basis sets with increased flexibility in time-frequency partitioning. The bandwidth efficiency and power spectral density for the general signal have been analytically derived and it is shown that these figures of merit, for every possible permutation of wavelet packet filter banks, are equivalently that of standard QAM. Hence, WPM is directly applicable in all existing systems employing this modulation format, with the added benefit of arbitrary time- frequency plane configurations. This benefit is not to be understated - flexibility in both time and frequency are extremely important for mitigating certain types of channel impairments, e.g. hostile narrowband and/or impulsive jamming/countermeasures. The fact that, by a simple hardware exchange, this flexibility is afforded for communication links currently in operation is of critical value to DoD-wide communication system designers. The following report details the work accomplished for this project - a survey of relevant work, wavelet packet modulation, the discrete implementation of WPM, and the spread spectrum extension of WPM.