Performance Analysis of a Link-16/JTIDS Compatible Waveform Transmitted Over a Channel with Pulse-Noise Interference
NAVAL POSTGRADUATE SCHOOL MONTEREY CA
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The Joint Tactical Information Distribution System JTIDS is a hybrid frequency-hoped, direct sequence spread spectrum system that utilizes a 31, 15 Reed-Solomon RS code and cyclical code-shift keying CCSK modulation for the data packets, where each encoded symbol consists of five bits. In this thesis, an alternative waveform consistent with the existing JTIDS channel waveform is analyzed. The system to be considered uses 31, 15 RS encoding as the original JTIDS, but each pair of five-bit symbols at the output of the RS encoder undergo serial-to-parallel conversion to two five-bit symbols, which are then independently transmitted on the in-phase I and quadrature Q component of the carrier using 32-ary orthogonal signaling with 32 chip baseband waveforms such as Walsh functions. This system is consistent with the direct sequence waveform generated by JTIDS. The performance obtained with alternative waveform is compared with that obtained with the existing JTIDS waveform for the relatively benign case where additive white Gaussian noise AWGN is the only noise present as well as when pulse-noise interference PNI is present. Errors-and-erasures decoding EED as well as errors only decoding is also considered. Based on the analyses, we conclude that the proposed alternative Link-16JTIDS compatible waveform performs better than the existing Link-16JTIDS waveform in AWGN as well as when PNI is present for both coherent and noncoherent demodulation. No significant advantage is obtained by using errors-and-erasures decoding EED for the alternative Link-16JTIDS compatible waveform.
- Radiofrequency Wave Propagation