This paper deals with the linear discrete-time sensor scheduling problem in unreliable communication networks. The sensor scheduling problem, where one sensor from a sensor network is selected for performing a measurement at a specific time instant so that the estimation errors are minimized, can be solved off-line by extensive tree search, in case an error-free communication is assumed. The main contribution of the proposed scheduling approach is to introduce a prioritization list for the sensors that leads to a minimization of the estimation error by selecting the most beneficial sensor even in case of unreliable communication. To lower the computational demand for the priority list calculation, an optimal pruning approach is introduced.