Exploiting the synergies of circular simplex turbo block coding and wavelet packet modulation

This paper describes an experimental implementation of an interference avoidance waveform, suitable for mobile or fixed wireless channels, and comprised of orthogonal signaling using wavelet packets in cohesive combination with a multidimensional channel error coding technique. The patent pending adaptive waveform, known as circular simplex turbo block coded wavelet packet modulation (CSTBC-WPM), possesses an unrivaled time-frequency localization and agility capability for avoiding joint narrowband/impulsive interference patterns. Excision of residual interference at the receiver is facilitated by isolation to a sparse number of time-frequency cells and removal using energy thresholding. Moreover, the time dilation of symbols in the WPM subbands is useful in mitigating the adverse effects of multipath-induced, frequency-selective fading. For an even more potent countermeasure to nonGaussian interference sources and channel propagation anomalies, the patent pending CSTBC forward error correction component is distinctly mapped onto the orthogonally multiplexed WPM symbols and interleaved to exploit the subband frequency diversity. The shorter block sizes of CSTBC provide a bit error rate performance competitive with turbo product coding's large code blocks, approaching the Shannon limit but with considerably lower latency (up to 20-fold improvement).