Available frequency bands are getting more valuable nowadays, due to the growing need for bandwidth of radiocommunication services. This implies a growing need for more and more effective frequency management procedures as well. Up to the present knowledge, the only proper solution in the broadcast area is to operate digital video broadcasting systems as single frequency networks. Such a network can be realised by modern OFDM-based methods.
In my thesis the coverage area plans of the terrestrial digital video broadcasting (DVB-T) system in Budapest at frequency 610 MHz for portable outdoor reception were created, in cooperation with the National Media and Infocommunications Authority of Hungary (NMHH). We compared the results of our plans with practical measurements, taking into account theoretical statements about single frequency networks.
As a consequence of our work, it can be declared that single frequency networks have almost no positive features which could verify our preliminary expectations about their effectiveness. The phase relations of signals coming from different transmitters are not considered either in theory or in planning. The effects of phase difference are getting more significant in an environment having lots of reflections and many transmitters.
In my thesis a comparison is given between planning models and measurement’s results. Suggestions are given about possible modifications in the operation of single frequency networks, aiming good reception.
In spite of the previously mentioned weaknesses, single frequency networks are still to be dealt with, as they have one great advantage compared to the multi frequency broadcast networks. This benefit is the spectral effectiveness, which has become the most important aspect in network planning now due to the scarcity of the frequency spectrum.