Quantifying the availability of TV white spaces for cognitive LTE systems in China

The explosive growth of capacity-hungry wireless services are presenting challenges to the scarce spectrum resource. Operating LTE systems on TV white space may meet the capacity demand due to the good propagation characteristic. However, according to the decision on World Radiocommunication Conference 2012, TV white space is unable to be used by LTE systems exclusively in the near further in China. Cognitive technologies throw light on sharing TV white space between LTE and TV broadcasting systems. Taking 470- 806 MHz band as an example, the availability of deploying LTE systems on TV white spaces in China is studied in this paper. Firstly, the separation distance from LTE stations to the edge of TV coverage area is calculated. Then, the inter-site distance between TV and LTE stations are figured out using the separation distance and TV coverage radius. Combining the theoretical calculation with the deployment information of both analog and digital TV stations stored in the national station database, simulation results on the capacity distribution of cognitive LTE system in typical cities are given. The simulation results inferred that approximately 67% of TV channels are unused averaged over the cities. This result confirms quantitatively the often-stated expectation that white spaces can be shared by LTE systems to meet the capacity demand as well as improve the spectrum efficiency.