model_info

网络仿真软件OPNET TDMA的模型文件

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Summary:        This model demonstrates a time division multiple access 
                (TDMA) protocol in which several nodes share a single 
                radio channel.  

Model Name:     Time Division Multiple Access (V.2) - tdma.prj
Created on:     1/7/95
Last Revised:   12/21/98
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Introduction:
The model contains two subnetworks and a bent pipe satellite node.  A
node within one subnet sends data to the satellite, which forwards it
to the other subnet.  The nodes within a subnet follow the TDMA
protocol when sharing the uplink channel to the satellite. The TDMA
Version 2 model also fixes several bugs in the original TDMA model,
updates the remaining OPNET 2.5 functionality, and allows for the 
mixing of fixed, mobile, and satellite nodes.

Understanding the model:
This model uses a simulation attribute named "slot_length" that
specifies the time length of the slots into which the channel will be
divided.  At the beginning of the simulation, each node determines two
values: its multiple and offset.  The multiple is the number of slots
per channel and is the same as the number of nodes in its subnet.
Thus each node receives an equal amount of the channel bandwidth.  The
offset of each node is its index within the rotation of slots.  Thus
the channel is multiplexed into slots in a round-robin service
fashion.

The satellite uses two directional antennas.  At the beginning of the
simulation, they are pointed directly towards the node "gnd_0" within
each subnet.  A custom rxgroup pipeline stage, bent_pipe_rxgroup, has
been added to improve execution speed.

In tdma-slot_half, "slot_length" is defined to be 0.5.  In tdma-slot_one,
"slot_length" is defined to be 1.0.  Run simulations from the advanced editor.
Each scenario has its own animation for viewing.

To prepare the model for execution, make sure the tdma contributed model 
directory is included in the model directories list in your env_db<rel> file.