A Wireless Network Test Emulator with repeatable results
A Wireless Network Test Emulator (WiNe TestEr) is being developed by a research team from the Department of Computer Science at The University of Texas at Dallas (UTDallas) to run controlled experiments on wireless networks. Dr. Ravi Prakash, Dr. Subbarayan Venkatesan, and Dr. Neeraj Mittal work with some additional researchers from Southern Methodist University (SMU). To appreciate their work, some information about wireless devices is needed.
Government regulations are in place to limit the frequencies used by wireless devices. Permits are required for wireless devices with frequencies in a particular range, referred to as licensed frequencies. Permits are not required for wireless devices with frequencies in another range, referred to as unlicensed frequencies. Some examples of licensed frequencies are those used by the various phone carriers, and broadcast TV. Some examples of devices that use unlicensed frequencies are garage door openers, baby monitors, and wireless access points used in homes for WiFi network access.
Government regulations also limit the signal strength. In general, all wireless devices do their best to transmit signals, at a particular frequency and not exceeding the maximum permitted signal strength. But, signal strength will vary for a variety of known and unknown reasons. Factors such as temperature, humidity, and interferers (like microwave ovens) are known to affect signal strength, but the effect is not predictable. Clearly, wireless devices must be able to work at a particular frequency AND at a range of signal strengths.
Normally, when wireless devices are tested with over-the-air transmissions, the results tend to vary. For example, a wireless car trunk opener will not always work at a particular distance. The strength of cell phone reception (“bars”) will vary, at the same location, on different days. The unpredictability and variability of the signal strength of wireless devices makes it difficult to test them. Test results of wireless devices are usually not repeatable due to variations in parameters beyond the experimenters’ control.
The WiNe TestEr can test devices at a controlled set of signal strengths. The devices are connected to the WiNe TestEr (bypassing the antennae) using shielded cables, which simulate the wireless transmission to the base station. The test will quantify the ability of the wireless device to communicate with its base station over a controlled set of signal strengths. Test results with the WiNe TestEr are REPEATABLE!
The WiNe TestEr can simultaneously test tens of wireless devices and can emulate several topologies and arrangement of interconnection among devices. For example, a star configuration of 100 wireless devices connecting to one hub, or two hubs, or three hubs can be emulated. Many configurations can be emulated and tested. Also, the emulator can support multiple and simultaneous experiments.
This project is an extension of project funded by the DOD at UTDallas for two years that resulted in the Texas Networking Testbed (TNT). The National Science Foundation (NSF) awarded a $1 Million research grant to UTDallas and SMU to make improvements over TNT. The WiNe TestEr has better channel emulation and a better user interface than the TNT.
Companies, with interests in wireless devices, have also supported the research and development of the WiNe TestEr. Other companies, interested in testing their wireless devices with the WiNe TestEr, should contact Dr. Ravi Prakash via email at ravip@utdallas.edu.
Dr. Ravi Prakash is a professor in the Department of Computer Science at UTDallas [www.utdallas.edu/~ravip]. His research interests include wireless networking, sensor networking, mobile computing and distributed algorithms. He is a past Chairman of the IEEE Dallas Section, and a member of the UT Dallas Faculty Senate and Academic Council. In the past he served as an associate editor of the IEEE Transactions on Mobile Computing and as the Secretary of the IEEE Dallas Section.
Dr. S. Venkatesan (Venky) is a professor in the Department of Computer Science at UTDallas [www.utdallas.edu/~venky]. His current research efforts are in wireless sensor networks and its application to medical instrumentation, cognitive radio networks, mobile ad hoc networks (MANETs), fault tolerance, distributed algorithms, telecommunication networks, and mobile computing. He holds several patents and is the author of numerous publications, listed on his website.
Dr. Neeraj Mittal is an associate professor in the Department of Computer Science at UTDallas [www.utdallas.edu/~neerajm]. His areas of interest include distributed algorithms, fault-tolerant computing, multi-channel wireless networks, key management, and software transactional memory. He is the author of numerous publications, listed on his website.
The Department of Computer Science at UT Dallas [www.cs.utdallas.edu] is one of the largest CS departments in the United with more than 750 undergraduate, 500 master, and 125 PhD students. They are committed to exceptional teaching and research in a culture that is as daring as it is supportive.