High throughput, power and spectrally efficient communications in dynamic multipath environments

Abstract

Many military applications require robust high data rate communications in severe mobile, multipath or highly dynamic environments. In these cases minimizing size and maximizing power efficiency is usually also of great interest. Examples include terrestrial communications in urban settings where line of sight may not be available as well as links to highly dynamic aircraft and missiles. Most high throughput, bandwidth efficient waveforms in use today (e.g. OFDM or QAM) are very sensitive to dynamics and multipath. They also are often characterized by significant peak to average transmit power that prohibit the use of more efficient transmitter designs. Extensive trade-off analysis and simulations were performed for selecting the coding and constant envelope (power efficient), spectrally efficient modulation schemes combined with receive processing, that achieves "turbo-like" performance. The implemented receiver combines soft-input/soft-output (SISO) equalization and decoding via adaptive iterative detection (AID) techniques and exhibits excellent performance even in severe dynamic multipath fading channels with large delay spreads. Reduced complexity algorithms were designed for hardware implementation and their performance was evaluated.