fixed and portable access applications in a typical cell radius deployment of three to 10 kilometers wimax systems can deliver capacity of up to 40 mbps per channel for fixed and portable access applications wimax systems operate in licensed and license exempt bands between 2 6 ghz rf spectrum for example between 3 3 to 3 8 ghz and 5 7 to 5 8 ghz bands these profiles cover both tdd and fdd systems other system profiles can address the 5 8 ghz license exempt band and the 2 5 and 3 5 ghz licensed bands one embodiment conforms to the ieee 802 16e the mobile wireless metropolitan area networks wirelessman standard that will facilitate the global development of mobile broadband wireless access bwa systems the 802 16e system supports a combined fixed and mobile bwa supporting subscriber stations moving at vehicular speeds in licensed bands under 6 ghz meshes of wifi or wimax units can be combined to provide metropolitan area network as well as extending into a national area network the wifi or wimax mesh network topology is a semi mobile system because the connectivity position among the nodes may vary with time due to node departures new node arrivals and roaming nodes a node can send and receive messages so wireless data will find its way to its destination by passing through intermediate nodes with reliable communication links thus data must u201c hop u201d through neighboring devices to reach its final destination this multi hoping capability is designed to create a robust meshed network that automatically routes congestion and line of sight obstacles while improving throughput as subscriber density increases.