LTE over Cognitive Radio networks: the power of TV white spaces

Cognitive Radio concept is introduced as an enabling technology for managing and controlling the allocation of frequency spectrum. It has gained considerable maturity during the last years. This emerging approach not only promises great future technological advances and seems to meet many needs of today, but also could be exploited for enhancing a wide range of legacy technologies in particular those frequency-spectrum-based. The digital dividend has raised huge interest among different telecom players as a great opportunity for leveraging the TV white spaces to deploy and enhance next generation cellular networks such as Long Term Evolution (LTE).

Unlike the ISM bands, international regulatory agencies do not authorize the license-exempt devices to operate on the TV bands except for certain equipment types like remote control, medical telemetry devices and wireless microphones. Such characteristics have made the TV bands a real candidate for assisting 4G deployments. Many are the opportunities offered by the use of TV bands to foster further LTE expansion. For instance, a recurrent scenario that may occur is the fact that some users start a call or a data transfer using the legacy LTE bands, meanwhile the coverage may  become week or unavailable; the desired service may continue automatically using some backup bands, namely, the TV white spaces. Further, one feasible option of LTE deployment is to start by the reuse of the existing TV white spaces as intermediate and temporary situation and later migrate the traffic to the commercial 4G bands once the LTE mobile auction is won; especially given that the auction process is slow, very long and expensive (billions of dollars).  Besides, extending the traffic of the fourth generation mobile networks beyond the 1.8 GHz and 2.6 GHz coverage area may relax pressure on the existing LTE infrastructure notably in large cities, and may ensure mobile services provision even in the borders since TV bands have a larger scope and better penetration. Therefore, the objective of increasing the number of connected customers is promoted, which is very important for operators and wireless network subscribers. Additionally, lower bands, which is the case of TV bands, make possible the manufacturing of smaller antennas for simpler and less cumbersome smartphones.

These reasons, among many others, have rendered necessary the reconsideration of the traditional network planning process in order to meet the expectations of the new era of services. Before being an opportunity, the concept of cognitive radio brings a paradigm shift as a key solution for various problems encountered by operators such as band saturation, weak deployments in rural zones and high quality of service demands [1].

BIBLIOGRAPHY

[1] SILVA, C. F., ALVES, H., & GOMES, A. (2011). Extension of LTE Operational Mode over TV White Spaces. Proc. of Future Network and Mobile Summit.