The colliding beams of heavy ions (Au+Au, Pb+Pb or Bi+Bi), currently planned for NICA at JINRwith the average luminosity at the level of1027cm2/s, will provide the vast amounts of precise dataat the center-of-mass energies up to 11 GeV per pair of nucleons. This will give the possibilities for he detailed, event-by-event studies of properties of high-density baryonic matter in the region ofthe expected onset of deconfinement, as well as for the search of the critical first-order end-pointof the phase diagram of strongly interacting matter and of some signals of chiral symmetryrestoration. With the aim of selection the events of interest, it was proposed in [1] to create a fastbeam-beam collisions monitor, which would determine the time and space of each ion-ion collision,providing also the event-by-event information on the relevant multiplicity of charged particles.Circular (segmented ring-shaped) detectors on the microchannel plates (MCP) with high timingcharacteristics (signal duration below1ns) were suggested to be placed in vacuum of the beam-pipeat some distance from the interaction of the ion beams. The multipad readout system has to ensurethe time-of-flight measurements with the accuracy below50ps, and multiplicity and azimuthaldistributions of particles produced in collision.In this report, we present our results of MC simulations of the beam-beam collisions monitoringsystem at NICA based on the MCP detectors. Different generators SMASH1.8[2], UrQMD [3],DQGSM [4] were used with the purpose to estimate the accuracy in determination of the positionof the interaction point and multiplicity in the event. The assessments take into account the arrivaltimes of particles to the detector, the rising edge of the current pulse in the MCP channels, theinfluence of communication lines, electronic equipment, and information retrieval technology.The performed calculations show that it is the signal formation time in the microchannel plates thatbrings the main contribution to the error in determination of the interaction point. Calculationsconfirmed also the possibility of determining by this compact detector system the event multiplicityby using MCP detectors in the counting mode. The possibilities of event-by-event measurementsof arrival times for different types of charged particles coming from the interaction point are alsodiscussed.Acknowledgments: the study was supported by RFBR, research project No. 18-02-40097.References:1. A.A. Baldin, G.A. Feofilov, P. Har’yuzov, F.F. Valiev, NIMA958(1), 162154 (2020).2. J. Weil, V. Steinberg, J. Staudenmaieret al., Phys. Rev. C94(5), 054905 (2016).3. S.A. Bass, M. Belkacem, M. Bleicheret al., Prog. Part. Nucl. Phys.41, 225 (1998).4. K.K. Gudima, S.G. Mashnik, A.G. Sierk, Report LA-UR-01-6804, Los Alamos (2001)