Dear Prabhleen Sing,

Please follow this article.

Hello, please find below attached link.

http://www.cse.wustl.edu/~jain/cse567-11/ftp/sensor/index.html

I would recommend NetSim from http://www.tetcos.com . It has excellent support for 802.15.4 based WSNs. You can also interface it with MATLAB and example projects / codes are available at http://tetcos.com/file-exchange.html that you can check.

I know few researchers at AUT are using OPNET Modeler (ZigBee) to model WSNs.

You can use NS2 if you want to work with packet level aspect.

I would suggest for Omnet++ with MIXIM framework.

u can choose simulator based on your requirement work .for myself, I prefer network simulator NS-2