Frequency Planning for Digital Terrestrial Television (DTT) in South AmericaPlanificación de Frecuencias para Televisión Digital Terrestre (TDT) en Sudamérica
Jefferson Alexander Ribadeneira Ramírez
Digital Terrestrial Television (DTT), offers greater robustness against noise and interference, more efficient use of radioelectric spectrum by the possibility of using single frequency networks (SFN) and the possibility of transmitting several television channels for the same radio channel. In addition, it is possible to provide value-added services such as HDTV and 3D. In the transition from analog to digital television, it must be perform a first stage of simulcast, where both analogue and digital signals should coexist. In this stage, a critical point is the low availability of frequencies. Therefore, first it is necessary to perform a frequency planning at regional level between the countries and internally for each country. Due to the high power that DTT transmitters normally radiate, and the locations of the transmitters at high points, frequency planning at regional level should take into account coordination areas and protection distances inside the border of each country. Finally, DTT network planning should be perform for the assigned frequencies. Additionally, the most efficient usage of the radio electric spectrum involved the introduction of the DTT, have allowed the release of certain frequency bands traditionally allocated for broadcasting. The released bands are known as Digital Dividend (DD), and correspond to the 800 MHz band (790-862 MHz) and 700 MHz (698-806 MHz) in Europe, and 700 MHz band in America. These bands have been allocated for the use of fourth generation mobile communications 4G LTE. The inclusion of LTE in the digital dividend bands, represents an additional problem for the deploy of DTT networks. Because both, DTT and LTE networks must coexist in adjacent frequency channels. Therefore, two coexistence cases must be considered. On the one hand, to the deployment of new DTT networks, must be analyzed the potential interference from LTE networks, as well the possible solutions to mitigate the interference. Moreover, for DTT networks already deployed, interference problems must be solved at the lowest possible cost and impact. This thesis deals with frequency planning for DTT networks in South America, where several DTT standards have been adopted. Most countries in the region have adopted the Japanese-Brazilian standard ISDB-Tb. However, Colombia has adopted the European second generation standard DVB-T2, with the particularity that Colombia is the first country in the world in which DVB-T2 must work with 6 MHz channelization, and must coexist with the analog TV standard NTSC. This along with the late release of the DD band in America, presents a much more complex scenario for DTT planning network in the region. First the frequency planning at the regional level for all countries of South America is studied, later the frequency planning at national level for Colombia is addressed. For this purpose, is investigated the coexistence of the European second generation standard (DVB-T2), the Japanese-Brazilian first generation standard (ISDB-Tb), the American analog TV standard NTSC and the mobile communications standard LTE working in digital dividend bands, as well as different technical solutions to mitigate interference on DTT networks. Finally, the recommendations of coexistence between analogue television networks NTSC, digital television networks ISDB-T, DVB-T2 and mobile communications networks 4G LTE are presented. These recommendations constitute a useful handbook for DTT network planning in South America.