Accession Number : ADA186069

Title :   Performance Analysis of Coded Frequency-Hopped Spread-Spectrum Systems with Unknown Interference.

Descriptive Note : Technical rept.,

Corporate Author : MICHIGAN UNIV ANN ARBOR COMMUNICATIONS AND SIGNAL PROCESSING LAB

Personal Author(s) : Hedge, M V

PDF Url : ADA186069

Report Date : Aug 1987

Pagination or Media Count : 117

Abstract : Two classes of problems are considered. In the first class we model the process of communicating in the presence of interference, which is unknown or hostile, as a two-person zero sum game with the communicator and the jammer as the players. The objective functions we consider are mutual information and the channel cutoff rate. The communicator's strategies are distributions on the input alphabet and on a set of quantizers and the jammer's strategies are distributions on the noise power subject to certain constraints. We consider various conditions on the jammer's strategy set and on the communicator's knowledge. For the case with the decoder uninformed of the actual quantizer chosen, we show that, from the communicator's perspective the worst-case jamming strategy is a distribution concentrated at a finite number of points thereby converging a functional optimisation problem into a nonlinear programming problem. Moreover, we are able to also characterize the worst-case distributions by means of necessary and sufficient conditions which are easy to verify. For the case with the decoder informed of the actual quantizer chosen we are able to demonstrate the existence of saddle-point strategies.

Descriptors :   *CODING, *FREQUENCY AGILITY, *JAMMING, *SPREAD SPECTRUM, ALPHABETS, CHANNELS, DISTRIBUTION, INPUT, NOISE, NONLINEAR PROGRAMMING, PERFORMANCE TESTS, POWER SPECTRA, QUANTIZATION, STRATEGY

Subject Categories : Countermeasures

Distribution Statement : APPROVED FOR PUBLIC RELEASE