Downlink Capacity of Super Wi-Fi Coexisting with Conventional Wi-Fi

Super Wi-Fi is a Wi-Fi like service over TV white spaces (TVWS) based on the dynamic spectrum access (DSA) technology. Although Super Wi-Fi is expected to achieve larger coverage than conventional Wi-Fi thanks to the superior propagation characteristics of TVWS, it suffers from smaller bandwidth than Wi-Fi (6-8 MHz versus 20 MHz) which degrades network capacity. Therefore, it is common belief that the two Wi-Fi technologies may target different applications such as Super Wi-Fi for coverage and Wi-Fi for speed. However, there is a lack of studies that rigorously analyzes and compares the performance of Super Wi-Fi and Wi-Fi to confirm such belief. To fill the gap, this paper performs a thorough analysis on the capacity of Super Wi-Fi under the scenario that a Super Wi-Fi access point (AP) coexists with a Wi-Fi AP. Comparing the downlink capacity of Super Wi-Fi and Wi-Fi reveals that Super Wi-Fi can outperform Wi-Fi at the outskirts of the Wi-Fi's coverage and Super Wi-Fi gets more beneficial when channel bonding is employed. In addition, the maximal coverage radius of Super Wi-Fi is derived with which Super Wi-Fi can achieve better average capacity than a network of densely-deployed Wi-Fi APs, where the maximal radius is up to 3.2 times larger than the coverage radius of Wi-Fi

Comparing Downlink Capacity between Super Wi-Fi and Wi-Fi in Multi-Floored Indoor Environments

Department of Electrical EngineeringSuper Wi-Fi is a Wi-Fi-like service exploiting TV white spaces (WS) via the cognitive radio technology which is expected to achieve larger coverage than today???s Wi-Fi thanks to its superior propagation characteristics. Super Wi-Fi is currently being materialized as an international standard, IEEE 802.11af, targetting indoor and outdoor applications. This thesis demonstrates the potential of Super Wi-Fi in indoor environments by measuring its signal propagation characteristics and comparing them with those of Wi-Fi in the same indoor structure. Specifically, this thesis measures the wall and floor attenuation factors and path-loss distribution in 770 MHz and 2.4 GHz, and estimates the downlink capacity of Super Wi-Fi and Wi-Fi according to wide-accepted indoor path loss models. The experimental results reveal that TVWS signals can penetrate up to two floors and provide favorable coverage up to one floor above and below. In addition, TVWS can not only extend the coverage of Wi-Fi but also significantly mitigate shaded regions of Wi-Fi while achieving almost homogeneous data rates in the Wi-Fi???s coverage. The observed phenomena imply that Super Wi-Fi may be suitable for indoor applications with requirements of low-to-moderate data rates, extended horizontal and vertical coverage, and fair rate distribution within the service coverage.ope