Noise immunity of the reception of coded orthogonal signals in a multiple-access channel with two-level quantization of the total signal

The probability of an error in a multiple-access communication channel with the code division of N users is studied analytically and numerically. Data symbols are transmitted using Walsh-Hadamard sequences of length L. The studies were conducted in the case when two-level quantization was applied at the output of a demodulator to the total signal from all users and the mutual user interferences produced the dominating disturbing effect in the common frequency channel. The possibility of the error-free reception of a data symbol is demonstrated when "the best" code table for N users is selected in the presence of only mutual user interferences in a weakly loaded communication channel. A nonmonotonic behavior of the probability of an erroneous decision about the type of the data symbol is revealed for the case when the code table is composed of the first N Walsh-Hadamard sequences.