Reducing secondary user collisions in TV White Space through a Geolocation Database Middleware
George Atta-Boateng, Patrick Otoo Bobbie, Kwame Osei Boateng, Emmanuel Kofi Akowuah · 2018
This Research Full Paper presents challenges and solutions of using the widely accepted Geolocation Database (GLDB), as the main Vacant Channel (VC) detection method in Television White Spaces (TVWS) technology, which is emerging as a potential alternative for supporting the increasing need for wireless transmissions. TVWS are unused and unassigned licensed spectra allocated to Primary Users (PUs) like TV stations. However, at any geographic location where VCs released by the GLDB are limited for multiple unlicensed Secondary Users (SUs) to transmit, due to contention, the tendency for collisions amongst the SUs is always high. To make the GLDB resilient, secured, and trusted, we propose a modified architecture by introducing a Dynamic Database Agent (DDA) Middleware, a layer between the main GLDB and the SUs. The DDA Middleware coordinates with the main GLDB to select available VCs for the SUs in a regulated pattern. The DDA depends on two critical pieces of information: 1) all incoming or arriving SUs at any geographic location and 2) the expected VC transmission time of every SU, which we term as Maximum Vacant Channel Occupancy Time (MVCOT). We model and simulate channel allocation techniques using the Normal GLDB proposed by regulators and our layered DDA Middleware GLDB. We measure the statistical probability of SU vs SU collisions for both databases to draw conclusions about the effectiveness of our approach. Simulated results show that our DDA Middleware intervention reduces collisions due to the co-existence of SUs by 52.3%.