Exploring RSSI Dependency on Height in UHF for Throughput Optimisation

This paper considers exploiting the unique outdoor propagation characteristics of the Ultra High Frequency (UHF) band to optimise wireless network deployments. The relationship existing between signal strength and antenna height in UHF band is analysed. Received signal strength increases steadily with an increase in receiver antenna height up to about 8.5 m above ground, which can be explained in part by the resulting effect of Fresnel zone and obstacle clearance such as typical house height in the area. When raised beyond 8.5 m further signal strength gain stifles, possibly due to effects of multi-path fading. The contribution of this paper is firstly, the implication of Received Signal Strength Indicator (RSSI) dependency on height and secondly, the consideration of throughput corresponding to RSSI thresholds

A Correlation between RSSI and Height in UHF Band and Comparison of Geolocation Spectrum Database View of TVWS with Ground Truth.

An investigation into the Received Signal Strength Indica- tor (RSSI) dependency on receiver antenna height in UHF band is con- ducted. The results show a high correlation between RSSI and height on channels with high signal strength. There is approximately 2.5 dBm RSSI gain per 1 m increase in height above ground up to 8.5 m. From 8.5 m to 12 m, there is no consistent observable increase in RSSI. Further- more, the geolocation spectrum databases (GLSD) view of white space in the television band is compared with the ground truth. Results show signal presence on some of the channels indicated free by the spectrum database. These findings imply that an increase in transmission range of UHF links can be achieved by increasing receiver height. White space devices using A GLSD should additionally require spectrum scanning to determine clear channels

A Road Map for Wireless Mesh Routing with DSA

Dynamic Spectrum Access (DSA) provides a new opportunity for last-mile and rural connectivity. However, the nature of DSA and varying environmental conditions means that desired spectrum is not always available. To that end, we have deployed a testbed using both DSA-enabled TV White Space devices and fixed spectrum WiFi (5GHz) in parallel to support communication between and within townships. Using this testbed, we will develop new algorithms to support wireless mesh routing in DSA networks

Head to Head Battle of TV White Space and WiFi for Connecting Developing Regions

TV White Space networks are gaining momentum worldwide as an important addition to the suite of wireless protocols available for connecting developing regions. However, there has been no thorough investigation of scenarios where TV White Space performs better or worse than alternative low-cost wire- less technology such as WiFi. This paper analyzes the performance of 5 GHz WiFi links and TV White space links using down-converted WiFi, typically used as wireless backhaul for poorly connected regions, in different scenarios including line-of-sight links and links obstructed by trees and structures. The experiments make use of 802.11a/b/g WiFi and TV White Space equipment that down- converts standard 802.11 a/b/g WiFi from the 2.4 GHz band into the UHF band. The paper finds that 5 GHz links outperformed TVWS where clear line-of-sight is available and point-to-point links are required. TVWS however is a clear choice where there are obstructions and where wider coverage is needed. Some interesting observations on the negative effect of TV transmissions in adjacent channels a few channel-hops away from the channel being used for TVWS are also provided