Some Are Born With White Space, Some Achieve White Space, and Some Have White Space Thrust Upon Them

A few steps from Shakespeare's spiritual home The Globe Theatre in London, the U.K. regulator Ofcom is formulating its own well-crafted play based on TV white spaces (TVWSs). Such work comfortably fits into the Shakespearean analogy of “some achieve white space” through implementation of clever twists to make white space available while not causing harmful interference to incumbents, noting that the U.K. is extremely busy in terms of spectrum usage. This paper reports on some of the work of by our trial within the Ofcom TVWS Pilot, building key observations on beneficial usage scenarios for TVWS through link testing examples. It also particularly investigates performance of TVWS in terms of availability and capacity, through these scenarios and more generally, strongly focusing on aggregation of TVWS resources. A number of key observations result from this paper, some of which we highlight here. First, in the U.K., and in Europe in general where local DTT deployment characteristics and landscapes are similar to the U.K., TVWS has most benefit potential in below-rooftop receiver and indoor deployments. This is even more so if local white space device (WSD) deployment is extensive. Given this, we define and assess key baseline scenarios that we term as “mobile broadband downlink” and “indoor broadband provisioning” (akin to Wi-Fi or small cells in TVWS). We also argue comparison with other scenarios/topologies through parameter changes, and we further demonstrate the strength of TVWS for the indoor case through link performance tests. A second key observation is that good TVWS availability is achieved through the sophisticated regulatory approach of Ofcom, noting that the same approach to TVWS is harmonized across Europe through the ETSI EN 301 598 standard. However, this is affected by scenario: high power, high transmitter (e.g., 30 m above ground level) scenarios have a particularly reduced and variable availability. Further, high capacities are achieved by aggregating TVWS channels, especially if non-contiguous aggregation is supported; and moreover, profound implications for WSD RF design are derived based on such results, particularly under contiguous aggregation or channel bonding. A third key observation is that TVWS yields significant future potential, despite headwinds such as the WRC 2015 decision to allocate 694-790 MHz to mobile broadband on a co-primary basis in ITU region 1.