sum of capacities of data portions of each connection of the transmission frame in both transmission directions does not exceed the predetermined capacity then the transmission timing of the data portions within the transmission frame is set in such a manner that transmission and reception intervals of each connection do not overlap accordingly scheduling can be optimised to meet both qos and half duplex requirements application_number US 51602204 A description the preferred embodiment will now be described in greater detail based on an h fdd scheduling scheme for scheduling uplink and downlink burst data transmission for half duplex terminals or connections at an air interface of a fixed broadband wireless access fbwa system e g according to the ieee 802 16 specification fig1 shows such an fbwa system which comprises an access point ap usually called base station bs and subscriber stations ss s 1 to s 4 an ss can either be an individual end user terminal or a group terminal with several end user terminals connected to it all data traffic goes through the access point ap so that the access point ap can control the allocation of capacity bandwidth on the radio channel the capacity is scheduled and allocated by the access point ap according to agreed traffic and or qos parameters fig2 shows an example of an fdd based mac protocol the downlink and uplink mac frames f 1 to f 3 are of constant length the downlink structure transmitted on a downlink carrier begins with a broadcast phase bp where information about uplink and downlink structure is announced the broadcast phase bp is followed by a downlink phase dp for transmitting data bursts in the downlink direction the uplink structure.