Nowadays, mobile operators are faced with a problem of shortage of radio resources required for qualitative customer services. One of the possible solutions is the framework named LSA (Licensed Shared Access), which is developed with the assistance of ETSI. The LSA spectrum is shared between the owner (incumbent) and LSA licensee (e.g., mobile network operator). At any time, LSA spectrum could be used by incumbent or mobile network operator but not together at once. In this connection, if the incumbent needs its frequency, then LSA band becomes unavailable for mobile operator. This leads to service interruptions for mobile operator users. In this paper, we describe two possible Radio Admission Control (RAC) scheme models of the 3GPP LTE cellular network within LSA framework as finite queuing systems with reliable (single-tenant band) and unreliable (multi-tenant band) servers. Multi-tenant band is assumed to be intolerant to traffic delay. The formulas for calculating the performances measures – blocking probability, probability of service interruption and probability of service band changing – are proposed. The numerical analysis is provided for LSA example scenario of aeronautical telemetry. © 2017, Springer International Publishing AG.