The article describes a random access channel optimization technique based on the choice of roots for constructing random access preambles, the detection probability of which is higher than the roots selected in the classical way according. The results of simulation modeling are presented for the entire set of preambles 839 samples long. It is shown that with an increase in the number of simultaneously transmitted preambles, the spread of possible values of the correlation coefficient increases, which directly affects the success of detection. The conclusion is made about the possibility of optimizing the characteristics of the random access channel, both in terms of the configuration of the random access channel resources and based on the rational choice of the roots of the signal-forming preambles.