A method (600) for controlling access to a wireless medium in a network. The method comprises dividing an access time to the wireless medium into fixed and repeated time rounds (300), wherein each time round includes a plurality of superframes (310) and each superframe includes a fixed number of time slots (420) (S610)； allocating a global beacon period (530) within a time round (S620)； and reserving subframes (410) within each superframe (300), wherein master devices can access the wireless medium at least during the reserved subframes (S630).
