Design
Overview for CR Routing
Users
create the TCL script to configure the number of radios and channels needed for
simulations. The basic idea is to create multiple radios or channels through
the TCL library according to user’s script, which invokes the creation of
several copies of LL, queue,
A. Equal number of Radios and channels
Figure 2(a) shows the design for routing when the radio and channel are equals. In this design, the channel is created for each radio.
B. Single radio
multi-channel
Figure 2 (b) shows the design structure for single-radio,
multi-channel structures. Multiple channel copies are created for this
structure. Although routing algorithms can still use the same design as shown
in figure 2 (a) for single-radio multi-channel by checking the radios being
used, existing
C. Unequal number of
radios and channels
Figure 2 (c) shows the design structure for multi-radio, multi-channel design with unequal number of radios and channels.
Due to the
limitation of NS-2 design structure, the interface for routing and
There are some existing works [6][7][9] to enhance the NS-2 to support multi-radio multi-channel based on the design as shown in figure 2. However, there are several disadvantages for this kind of design if we only adopt them for CR simulation, which are listed as follows.
·
·
· Since channels are created in the same way, these radios and channels have the same radio and spectrum characteristic, which is not sufficient to support the simulation in heterogeneous CR network.
·
The radio and channel number are equal. Some
routing and
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