Characterization of noncoherent spread-spectrum multiple-access communications

An expression for the decision statistic of the receiver in a noncoherent DS/SSMA communication system is obtained, and conditions are identified that allow key parameters in the expression to be modeled as a set of Gaussian random variables. The decision statistic is then characterized as an inhomogeneous quadratic form in Gaussian random variables. An applicable theorem is applied to obtain a new expression, a function of a set of independent Gaussian random variables, with the same distribution as the decision statistic. The results are used to determine the distribution for the decision statistic and to compute the average probability of error for the system. The effects of the length of the signature sequences and the number of interfering transmitters are illustrated