Determining the potential noise immunity of separation-demodulation of two intermittent mutually non-orthogonal signals by binary phase-shift keying

The growth in the number of mobile users of electronic communications services leads to the exhaustion of the radio frequency resource, which has made it urgent to find ways to reuse it. The use of methods from the modern theory of multi-user detection allows simultaneous transmission of a certain number of mutually non-orthogonal signals with different power in a common channel resource. These methods provide for the possibility of algorithms development for detecting and separating two digital signals in the processes of information transmission in radio channels with mutually non-orthogonal digital signals, which are the object of this study. Here, we propose a solution to the problem of determining the potential noise immunity of separation-demodulation of two mutually non-orthogonal BPSK signals, which involves taking into account the intermittency of their radiation. For this purpose, the results of the synthesis of the algorithm for detecting-separating two mutually non-orthogonal intermittent BPSK signals, optimal according to the criterion of minimum probability of error in estimating their discrete information parameters, have been used as initial data. This criterion is a necessary condition for solving this problem. The characteristic differences of the represented methodology for analyzing potential interference immunity are the absence of restrictions on the energy characteristics of signals, the degree of their non-orthogonality, and the probability of radiation. The results allow developers to determine in practice the minimum required differences in the instantaneous signal powers in order to achieve maximum energy efficiency of radio channels under the given requirements for the error probability. In particular, it has been shown that the difference in such powers should reach at least 5÷6 dB in the case when both signals are emitted continuously, and with optimal detection and separation of intermittent signals, this difference increases to 9÷10 dB, depending on the degree of mutual non-orthogonality between the signals