OPNET Technologies
7255 Woodmont Avenue
Bethesda, MD 20814
Tel: 240-497-3000
Fax: 240-497-3001
E-mail: university@opnet.com
Web: www.opnet.com

© 2008 OPNET Technologies, Inc.
OPNET and OPNET Technologies Inc.
are registered trademarks of OPNET.
All trademarks are the property of their
respective owners and are used herein
for identification purposes only.

University: University of Nevada, Las Vegas
Name of Sponsoring Professor: Dr. Ju-Yeon Jo
Department: School of Informatics

Research using OPNET Modeler

Performance analysis for WLAN hotspots with WiMax Backhaul

802.11 Wireless LAN creates small hot spots allowing client machines to access the Internet wirelessly. Those hot spots are generally connected to the Internet through a wired medium such as DSL or cable modem. However, in remote areas or in mobile environment, wired backhaul connection is not cost-effective or even impossible.

WiMax is a wireless MAN technology typically covering a large area with several miles radius. It offers a good alternative for the backhaul to the WLAN hot spots. The WLAN hot spots can be either stationary or mobile. For example, a train or a bus may offer a WLAN AP for the passengers on board. The latest WiMax standard 802.16e can support both stationary and mobile hot spots.

We plan to investigate several issues in such an environment.

1. What is the practical number of users per WiMax channel, or how many WiMax channels/ bandwidth do we need to allocate given the user activity?
   Under various usage scenario, what is the most efficient algorithm for aggregating multiple user traffic?
2. Can we provide QoS support for the WLAN users?
   Although WiMax offers QoS, the WLAN clients do not have the capability to utilize it since they are connected indirectly through a WLAN AP. Is it possible to detect the QoS requirement from the users' traffic? Then, how accurately can we do it?
3. In both stationary and mobile hot spot, we have two wireless links with different packet loss characteristics. Are the bit errors between them distinguishable? How do we utilize it improve the TCP performance?
4. Does the WiMax backhaul work efficiently for mobile hot spots?
   Can it support real-time traffic reliably? How does the Best Effort traffic performance compare with a wired backhaul?
5. As a conclusion, is the 802.16e mobile WiMax standard adequate to support WLAN hot spots? What improvements are suggested?

We will study above topics using OPNET Modeler with WiMax module.

Teaching with OPNET Modeler

CS 466/666 Computer Networks II

Catalog Description:
Explores advanced topics in computer networks, the protocols, algorithms, hardware, and performance issues, especially in TCP/IP networks. Details of IP routing algorithms, quality of service, protocol implementation issues, router architecture and types, various TCP versions and their performance, the related telecommunication networks, and wireless technologies are discussed. Prerequisite: CS 465. 3 credits.

Students will engage with hands-on projects in network protocol development and network simulation with OPNET modeler.

OPNET Technologies, Inc. is a leading provider of solutions for managing networks and applications. OPNET's best-in-class solutions address application troubleshooting, application monitoring, network monitoring, network configuration management, network planning , and network simulation. OPNET’s solutions have been operationally proven in thousands of customer environments worldwide, including corporate and government enterprises, government and defense agencies, network service providers, and network equipment manufacturers. For more information about OPNET and its products, visit www.opnet.com.