Method and tester for determining an error rate of a mobile-telephone device, especially for USF-BLER

A method and apparatus for determining an error rate is described, in which a transmission block having an allocation signal is received by a mobile communications device that is to be tested. The device checks whether it has been allocated the following transmission block by the received allocation signal. If an allocation is determined, a message signal is transmitted by the device to the tester in the following transmission block. It is then determined whether the device has received a message signal in the following transmission block after an allocation signal, which is addressed to the device. The number of allocation signals addressed to the device which have not been recognized is then determined, wherein the allocation signal to be transmitted is selected from an allocation signal addressed to the device and at least another allocation signal addressing another mobile communications device of the same transmission signal.