Dynamic Spectrum Access: Is TV whitespace the solution or only the start?

Spectrum has become a precious resource in many regions of our planet. This raises the demand for more innovative use of the resource than just distributing it amongst the eligible parties according to given standards or on a first come-first serve strategy. Given that even in populated areas many frequencies are unoccupied for most of the time, Dynamic Spectrum Access seems to be a solution. So far, in the license exempt areas, technologies like Wi-Fi, using Listen before talk, were the choice for many years. TV Whitespace as a new species of dynamic spectrum access now reaches out into the real licensed world of TV frequencies, using devices reporting their technical data plus actual location to a central spectrum database and receiving from there a list of available frequencies. From its nature, the service has a third level quality and priority and sits below TV stations and Program Making & Special Events (PMSE or LPAUX) devices like wireless microphones, competing there on a “Listen before Talk” strategy with other Whitespace devices. So far, the method is in operation on a permanent basis in the US since 2012. The concept sounds logical as PMSE devices are often only temporarily used, leaving empty space during the residual time. Lower priority services may jump in and fill these empty spaces. This works fine in rural areas but has massive limitations in urban and dense urban areas. In addition, the redistribution of the 700 MHz band, as decided by ITU, will increase the difficulties and challenges of any possible business model in the TV band. This article shows the current state of the art of TV Whitespace and its limitations. It also discusses the true potential of dynamic spectrum access and how the concept could be migrated into other bands.