Are superluminal "signals" an acceptable hypothesis? - Difficulties in building a communication protocol with them

The local hidden variable assumption was repeatedly proved unable to explain results of experiments in which contextuality is involved. Then, the correlated results of measurements of entangled particles, began to be attributed to a communication between particles through so-called "signals". These "signals" need to possess superluminal velocity or move backward in time. No object that has a rest-mass, not even the photons whose rest mass is zero, behave this way. Still, as the nature of the presumed "sinals" is not known, people don't reject the idea, despite the conflict with the theory of relativity. For this reason, the present article examines the "signals" from another point of view: wherever runs a communication, there has also to exist a communication protocol. The article tries to outline a communication protocol between the space-separated, entangled particles, and comes to a contradiction, making the idea of such a communication highly doubtable.