Improving vacant channel utilization in shared TV white space spectrum

Abstract

Television White Spaces (TVWS) are unused and unassigned channels called Vacant Channels (VCs) in the licensed broadband wireless spectrum allocated to TV broadcasters also called Primary Users (PUs). One of the major objectives for implementing TVWS technology in delivering broadband internet is to ensure the efficient utilization of VCs in wireless spectrum. To this end, the Geolocation Database (GLDB) has been widely accepted by regulators as the main technique for detecting VCs for use by unlicensed Secondary Users (SUs), because it offers better prospects in preventing harmful interference to licensed PUs. However, in the open literature, little attention has been given to its capacity to ensure that VCs assigned to SUs for data transmissions are fully utilized. There is the tendency for SUs to misuse VCs assigned to them, by staying idle for long periods without transmitting since there are no proper monitoring mechanisms. This denies other SUs the opportunity to access same channels, creating congestion and long queues. To mitigate this underutilization and ‘denial-of-use’ problem, we propose a Middleware architectural solution, called Database Bandwidth Regulator (DBR) for the GLDB to ensure efficient utilization of VCs. The DBR middleware makes use of the Bandwidth Consumption Cost (BCC) of SUs for data transmissions. We use Discrete Event Simulation (DES) technique to model and simulate both the regulated/normal GLDB and our DBR middleware GLDB. Statistical analysis of simulated results shows that VC utilization is improved by a factor of 4.1% with our DBR middleware intervention as compared to the regulated/normal GLDB.