=======================================================================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.prjCreated on:     1/7/95Last Revised:   12/21/98=======================================================================Introduction:The model contains two subnetworks and a bent pipe satellite node.  Anode within one subnet sends data to the satellite, which forwards itto the other subnet.  The nodes within a subnet follow the TDMAprotocol 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" thatspecifies the time length of the slots into which the channel will bedivided.  At the beginning of the simulation, each node determines twovalues: its multiple and offset.  The multiple is the number of slotsper channel and is the same as the number of nodes in its subnet.Thus each node receives an equal amount of the channel bandwidth.  Theoffset of each node is its index within the rotation of slots.  Thusthe channel is multiplexed into slots in a round-robin servicefashion.The satellite uses two directional antennas.  At the beginning of thesimulation, they are pointed directly towards the node "gnd_0" withineach subnet.  A custom rxgroup pipeline stage, bent_pipe_rxgroup, hasbeen 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.