A method is provided in a base station for handling a request from a first user equipment for accessing a service in a radio communications network. The method comprises the steps of receiving a first time interval of an incoming signal comprises a first signal sent from the first user equipment and a second signal sent from the second user equipment, interpreting the first signal as being a possible service access request message preamble, and sending an acknowledgement, that the preamble is detected, to the first user equipment. The method comprises the further steps of delaying the first time interval of the incoming signal, identifying the second signal in the first time interval of the incoming signal during the delay, washing the identified second signal away from the first time interval of the incoming signal during the delay, and deciding whether the possible preamble is a real preamble or not, by analyzing the washed incoming signal.