The present invention relates to the technical field of dynamic spectrum access. Synchronization of quiet periods for spectrum sensing can significantly benefit sharing of available secondary access spectrum between two or more wireless communication systems in the same geographic region. The object of the present invention is to provide a methodology by which quiet periods can be synchronized in time between different secondary access wireless communication systems. Quiet Period Clients (QPC) of secondary access wireless communication systems are adapted to send requests to a Quiet Period Server (QPS) to obtain a quiet period rule set. The QPC receives from the QPS an answer specifying the quiet period rule set, and optional quiet period synchronization information. The systems perform their transmissions in accordance with the received rules.