ND SatCom SKYWAN IDU 1070, Manual

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34 Network Design and Engineering Guide 2010-10-26
General Carrier Design
Essential SkyWAN
®
Satellite Link Layer Features
having to request the capacity first. This mechanism is only available for non real-time data!
Figure 2-16 Free Slot Assignment
Ranging Subframe
The ranging subframe is a number of consecutive slots allocated to slave stations which are
not yet registered in the network. These slots are not permanently assigned for this purpose. If
there are no unregistered stations in the network ranging slots can be allocated as dynamic
data slots. The size of the ranging section depends on the timeslot duration, typically it is in the
range of 1-5 base slots.
Figure 2-17 Slot Assignment with Ranging Subframe
Stream Slots
Stream Slots are triggered from data stored in the ’Real Time Transmit Queues’:
- Usage: for a real time application a station needs a constant data rate with low jitter (vari-
ance of delay). For a telephone call, the destination station will require the same data rate
for the way back.
- Examples: Speech, Video Conference, Video Streaming.