Researchers at the University of Bristol's Communication Systems and Networks Group have developed a new Wi-Fi test process that combines 3D antenna measurements with in-home virtual reality modeling. Professor Andrew Nix from the CSN Group in the school’s Department of Electrical and Electronic Engineering headed up the project.
“Our new technique allows Wi-Fi products to be rigorously and repeatedly analyzed,” said Nix. “Manufacturers can now optimize the speed and coverage of their products before they release them to their customers. Our co-operation with Farncombe has enabled a comprehensive Wi-Fi test that is well-tailored to the needs of video service providers. This is vital given the sophistication of the latest chip sets and the complexity of in-home radio wave propagation.”
Dr. Geoff Hilton, a specialist in advanced antenna design and co-developer of the process noted: “Modern Wi-Fi routers typically include between four and six internal antennas. The types of antenna, position, orientation and their proximity to other electronic components and the outer casing all make a significant difference. To predict the performance of a new product we need to measure how each of its antennas radiate in 3D space.”
The procedure involves characterizing the pattern and response of each antenna in an anechoic chamber. This provides a set of complex 3D antenna patterns that describe how the signals radiate to and from each antenna into the home.
“Once we have all the antenna patterns, we combine them with channel data from our virtual reality models,” Nix said. “Our test home is deliberately challenging, comprising 10 rooms spread over three floors. Electromagnetic ray tracing is used to calculate how the Wi-Fi signals flow, bounce and bend around the home between your wireless router and client, for example a tablet or mobile phone.”
Nix noted that the next step involved moving the router from room-to-room to ascertain coverage and service speed throughout the “home” environment.
“To reach our conclusion we analyze 1.44 million different Wi-Fi links inside the property,” he said. “Wi-Fi speed and coverage is computed using the CSN Group's own 802.11n simulator, which has been developed over a 20 year period. The simulator supports some of the latest Wi-Fi technologies, such as Eigen beam-forming with up to four antennas at the router.”
Many of the group's projects are covered by non-disclosure agreements, but Nix was able to announce that the latest product through the optimization process is the new Super Hub from Virgin Media. The University worked with prime contractor Farncombe on a set of benchmark tests to ensure the new router offered “best in class performance at 2.4 and 5 GHz.” In addition to the testing in the lab, Farncombe conducted empirical testing in real-world environments to support the University's analysis.
