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 sub-bands is useful in mitigating the adverse effects of multipath-induced, frequency-selective fading. For an even more potent countermeasure to non-Gaussian 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 sub-band 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).
展开▼
