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Author: Ajith Kumar (Admar Ajith Kumar Somappa)
Homepage: www.hib.no/ansatte/aaks
Title : Tutorial for creating own MAC Layer and simulation in Castalia Omnet++
	This will list the difference between MiXiM Mac and Castalia Mac
	MiXiM vs Castalia v2
Related: MiXiM Mac tutorial
References: Castalia, MiXiM, OMNET++
Weblink: Check User manual in
http://castalia.research.nicta.com.au/index.php/en/documentation
Section 5 Creating your own Module, page 89
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#To get better understanding check the manual for steps
#Start with putting in the folders given in proper place

myTestMac folder goes into
Castalia-3.2/src/node/communication/mac

MyMacSimulation folder goes into
Castalia-3.2/Simulations

Compile castalia after this.
to run the Simulation once you have compiled move to the simulation folder:

@comp:~/Desktop/Castalia-3.2/Simulations/MyMacSimulations$Castalia omnetpp.ini

Executes the general configuration I have setup.
You can setup more configurations if required.

#Commands to print simple graphs based on the result.

CastaliaResults -i test1.txt -s RX -n | CastaliaPlot -o graphRX.png

CastaliaResults -i test1.txt -s energy -n | CastaliaPlot -o graphEnergy.png

#test1.txt is the name of the output file created usually named with the date
#CastaliaResults uses the output files and CastaliaPlot plots a graph

-i is input
-s is to select a particular word
-n is for all nodes
-o is output for CastaliaPlot (a graph)

#For more details check the manual
#Further understanding on MAC is commented on the file itself.
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Once you have some understanding on working of Castalia and MiXiM this might help.

Note: The aim is to assist in creating a very basic MAC in both MiXiM and
Castalia, also addressing the necessary changes when migrating from one to
the other. (and not to compare MiXiM and Castalia)

There are major differences between the way the MAC is implemented on these
two platforms/frameworks. 
1. ChannelSense implementation is handled differently in both MiXiM and Castalia.
In Castalia radioModule->isChannelClear() can be used, that returns the present
channel state. In MiXiM channelSenseRequest message is defined which can be used
and in the MAC implementation the channel sense until idle is implemented by
sending the control down with message (UNTIL_IDLE: meaning sense until idle) 
when carrier sense is intiated. In Castalia I was not sure how pass on the control
hence have used self message to invoke MAC at a later time if carrier is busy. 
If you know how to do so you could suggest me.
for MiXiM check channelSenseRequest_m.h and cc
for Castalia check Radio.h and cc
"isChannelClear() returns the "current" state of the channel or NOT_READY indications.
In general it is built to resemble the interface that real low-power radios support. 
MiXiM's "sense until idle" functionality might be handy for developers as a 
higer level abstraction, but it does not model a realistic radio interface 
(although few radios might support this feature)."
2. MiXiM sends out radio_switching_over control command, which can be used
to make certain decisions. Castalia has it private. Thus has to be handled 
differently. Since this is simple MAC, we do not use timers etc. Use of timers
could make these implementation easier in Castalia. (Given that the time 
required to switch radio from RX to TX or TX to RX is usually known).
3. Radio States in MiXiM (default we can override):  TX, RX, SLEEP, SWITCHING
Castalia radio states: TX, RX, SLEEP
4. MiXiM: Radio switching to TX and to RX have to be handled by MAC.
Castalia: Radio switching to TX has to handled by MAC, Switch to RX is
handled by Radio by default.
5. Otherwise the skeleton is similar, does CSMA based Broadcast
using throughputtest application with highdata rate to see effects of
interference, when two nodes start transmitting with immediate succession
with a difference of 0.000006s.
6. Castalia gives the possibility to obtain RSSI, LQI from the Radio
and can be used in the MAC layer. In MiXiM these are not provided by default, but 
could be accessed otherwise.

Also for further information on using isChannelClear(), you can check TunableMAC.
If you have any suggestions or corrections you can e-mail me at:
a.ajith.kumar.s at gmail