Applicable Versions
NetSim StandardNetSim Pro
 
The MAC layer of 802.22 protocol will consist of two structures, namely Frame and Superframe. 

Each frame consists of:
Superframe preamble: is used for time synchronization
Frame preamble: is used for channel estimation
Superframe Control Header (SCH): carries BS MAC address along with the schedule of quiet periods for sensing, as well as other information about the cell

One superframe will be of 160ms duration. Each super-frame consists of 16 frames which are of 10ms duration each.
At the beginning of each super-frame, an SCH packet will be transmitted.


You can observe this by filtering control packet type to SCH and Receiver ID to any one of the nodes in the packet trace.
If you observe MAC layer arrival time, you can see that one super-frame will be of 160ms duration.


Each super-frame consists of 16 frames (Frame0 to Frame 15) and each of the frame will be of 10ms duration.
At the beginning of each frame, base station will transmit FCH packets.



You can observe this by filtering control packet type to FCH and receiver ID to any one of the node in the packet trace.
In the MAC layer arrival time, you can see that each frame will have a duration of 10ms.



A frame has two parts, Down-stream frame and Up-stream frame.
These are available in packet trace as DS-MAP and US-MAP.
Other than these, the frame contains UCD and DCD packets also.


After the transmission of these packets, the data packets will be transmitted.
You can observe super-frame and frames together by filtering control packet type to SCH and FCH and receiver ID to any one of the node.



The above packet trace shows a super-frame with 16 frames.
SCH denotes the begining of each super-frame and FCH denotes the beginning of each frame