Wireless Network and Communications Research CenterIllinois Institute of Technology Department of Electrical and Computer Engineering.
The spectrum for wireless networking is stressed and quickly reaching the limits of its capabilities. The objective of this research is to develop an in-depth understanding of this limit to network throughput and devise techniques to mitigate its effect. This research focuses on the growing noise/interference temperature that challenges the increasing use of wireless networks. A modeling and simulation capability will be established to aid in understanding the transmit and receive characteristics of key devices, and to comprehend the system-level issues for these devices operating in the presence of various forms of interference. The ultimate goal of the research project is to develop techniques to increase the capacity and connectivity of wireless communications networks by intelligent management of temporal, spectral, and spatial resources. This goal will be achieved by combining analytic models, system simulations, and experimental measurements so as to fully utilize the three dimensional wireless network space in the face of increasing interference.
In Spring of 2004 we submitted a proposal to NSF. The title of the proposed project was "Nets: ProWin: Wireless Spectral Interference and its Impact on Dynamic Network Connectivity". Over the Summer of 2004 we built a lab at Illinois Institute of Technology (IIT) devoted to this topic. Over the Fall of 2004 we devised models and analyzed noise interference due to 802.11a/b/g signals. We conducted various experiments to illustrate the concepts and learn about the nature of the interference caused by WLAN networks. In addition to that we began working on models of other interferers such as the microwave ovens, Bluetooth devices, cordless phones and whatever else emits signals in the ISM band. As part of our efforts we had NBC visit us for a presentation about the interference problem.
In the Spring of 2005 we continued our efforts by making simulations in MATLAB and conducting experiments. By the end of the Spring 2005 semester there was enough material for us to begin submitting papers to various conferences. During the Summer of 2005 we worked on several papers and got two of them published. We will soon have four more papers submitted and hopefully published. Refer to Publications to view our published papers.
Our research team is subdivided into three teams: Analytical, Experimental and Networking. The people on the analytical team work on derivations, mathematical equations and models, and MATLAB simulation. The people on the experimental team work with various test and measurements equipment to set up experiments for the analytical and networking group, as well as taking initiative to set up experiments that are useful for our research goals. The networking team performs simulations in OPNET and analyzes the issue from the networking point of view. Thus, the analytical team is focused more on the physical layer, the networking team is focused on the networking layer and the experimental team brings together the approaches of the analytical and networking teams.
These are our expectations of the results of our research effort:
Transmitter Models and Analysis
The transmitter models will be stochastic analytical models that provide characterization of various transmitting devices in the ISM band and the UNII band, such as a microwave oven for one example.
Receiver Models and Analysis
The receiver models will be fit to measurements and are going to consist of the transfer functions for the individual stages of the receiver.
The channel estimation models will characterize the effects of the channel on the power spectrum density (PSD) of the propagating signal at the measurement locations.
Simulations and Applied Scenarios
The simulations will provide computer models that will allow the integration of the analytical models for scenarios involving a variety of transmitters, receivers and environments.
Interference Temperature Estimation
Interference temperature will be estimated and calculated at the measurement locations. Interference temperature will be evaluated for its merit as a metric of the awareness for the wireless environment.
The results that we obtain will be published and made available. The simulation models once completed will also be available through this website.