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Figure: Carried and Offered
traffic
The traffic (in MBit/s), which is generated and offered to the network,
is recorded for each simulation interval, for each sector. In
case of CS services this is done based on the service bit rate and
the planned duration for each individual call. The traffic that is
actually carried by the network is also recorded. In the CS case this
can be done for all active mobiles based on the service bit rate. So
in CS simulations the difference between offered and carried traffic
is related to the dropping and blocking characteristics. In PS
simulations
the offered traffic is measured based on the generated packet data
and the carried traffic is recorded based on the successfully
transmitted
packets. In contrast to CS simulations the offered traffic of PS
services
is not only determined by the traffic settings (a-priori) but it
depends
also on the network performance and load. This is because of the
possible
feedback-loop in the PS traffic model (page reading time).
Figure: Carried/Offered
efficiency
The following figure depicts the Carried-Offered-Traffic curve
for a CS service simulation. The traffic is accumulated for several
cells. The maximum system capacity can be clearly seen in this example
as the point where the carried traffic does not increase significantly
for increasing offered traffic. Furthermore the ratio between carried
and offered traffic can be depicted depending on the number of mobile
stations per cell. In the example figure below a cell capacity of
approximately
38 mobiles per cell can be estimated for a tolerated carried/offered
traffic efficiency of 90%.
Simulator
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Output generated
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