The invention provides a method and system for file type identifying and analyzing, which is high in processing efficiency and accuracy, simple in parameter configuring and speedy in analyzing. In one embodiment, a Medium Access Control superframe format for a wireless communication network includes a beacon frame including beacon information for synchronizing devices in the wireless communication network and for defining structure of the MAC superframe, where the beacon information includes superframe structure information and synchronization information. The supporting apparatus includes a connecting bracket detachably mounted to the fixing bracket. In one embodiment, the present invention produces two reticle images side-by-side in the exit pupil of the optics of a step and scan wafer exposure system.