Using NS3 you can simulate WIFI. Because its a built in module in NS3. But still  yet NS3 is under development and resources of Ns3 are not so available except in NS3 official site. 

You can also use Ns2 instead of Ns3 because many more expert of Ns2 are available at  online also you can find many useful resources from blogging sites.

Thanks 

Using NS3 you can simulate WIFI. Because its a built in module in NS3. But still  yet NS3 is under development and resources of Ns3 are not so available except in NS3 official site. 

You can also use Ns2 instead of Ns3 because many more expert of Ns2 are available at  online also you can find many useful resources from blogging sites.

Thanks 

NS3 is a good choice

I would prefer to select Castalia. Go to following link for further details

https://omnetpp.org/models

Thank you all. Your link Mr yakoub indicates also that Castalia " is a simulator for Wireless Sensor Networks (WSN), Body Area Networks (BAN) and generally networks of low-power embedded devices." There are nothing indicating that Castalia simulates also high power devices ( exemple Wifi laptop, Wifi Access point ..). Castalia idicates that simulate Low power embedded devices. However, I need to simulte hybrid networks, high power network and low power network, exemple WBAN with Wifi laptop and wifi access point.

Please find the attached paper having lots of information on WBAN and evaluation. I feel you need information regarding This. Hope it helps. All the best for the Research.

Pls refer the following publication which discusses in detail the coexistence issue of WiFi and WBAN. It also has a section discussing the way the authors have performed simulation for the evaluation. I feel this paper will be of interest to you.

"Coexistence of ZigBee-based WBAN and WiFi for Health Telemonitoring Systems."

Kim Y, Lee S, Lee S.

All The best.

Thank you for your help. This will be interesting to the design of the simulation senario, but it does not revelate the kind of simulator that they use.

There is a current work carried in ns-3 to model effects of LTE interferences on wifi performance. This could be extended to your study, but you will have to add a WBAN model in ns-3 as well. 

See this link:

http://www.open-zb.net/wpan_simulator.php

I am working on both ns-3 and Castalia/OMNET++ (Castalia can import and run as a module of OMNET++). For simulating interference of WBAN or Wi-Fi, I think Castalia/OMNET++ is probably a good choice. ns-3 actually doesn't support WBAN, so you need to add your own WBAN model into it.

NS-3 is more suitable