Introduction to 802.16 WiMax, Wireless Broadband Technology, Market, Operation and Services

A radio packet is a short transmission (a burst) of information (data) that occurs on a radio channel. Radio bursts contains reference sequences ( preamble and possible a midamble), control information and payload of data.
The radio packet burst may have different types of radio characteristics such as modulation type, error coding, preamble length and transmission guard time periods. The combination of these characteristics is called the burst profile.
A burst set is a single transmission (RF packet) that contains a preamble along with one ore more bursts of information. The bursts of information contained within the RF packet may have different modulation and coding types. A burst frame is the complete set of information that is contained in a transmission burst.
The bursts within a burst set are sequenced according to their modulation complexity. Bursts with lower complexity modulation types are located at the beginning of the radio packet and bursts that follow can use modulation types with higher complexity (e.g. QPSK, QAM). This allows subscriber stations to receive and decoder all the bursts up to the burst with the highest modulation type it can receive.
RF bursts start with a sequence of bits (a preamble) that the receiving device can recognize and lock onto. Once the receiving device locks onto the preamble, it knows where to find the rest of the packets.
For longer RF bursts or bursts, midamble sequences may be periodically inserted to assist receivers in the decoding of bursts. A midamble is...