Implementation issues and evaluated performance in local service insertion in DVB-NGH single frequency networks
Abstract
Current digital terrestrial television networks make use of either single frequency networks (SFN) or multi frequency networks (MFN). SFN is the network where several transmitters transmit the same signal over the same frequency channel. MFN is the frequency network where each transmitter transmits the signal over different frequency channels. Compared to MFN,SFN is the best approach because of the efficient utilization of the Radio spectrum, Low power operation and multi-channel capacity. On growing market demand, need to maintain the quality, flexibility, mobility and interactivity successfully without any overloading and overlapping issues. For this we introduce the following two techniques. One is Hierarchical Modulation (HLSI) and another one is Orthogonal Frequency Division Multiplexing (O-LSI).In order to improve the performance of the SFN operation, DVB-NGH standard incorporates multiple input multiple output (MIMO) antenna diversity mechanisms. In this paper, we describe the benefits in the utilization of MIMO and its application to DVB standards, i.e. DVB-NGH and DVB-T2 (Terrestrial 2nd generation). Following a description of the transmission techniques adopted for the DVB-NGH specification, we furthermore provide theoretical and physical layer simulation results to illustrate the performance gains of MIMO in various channel models.
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Introduction
DVB technology has become an integral part of global broadcasting, where it has a set of open standards to use like satellite, cable, terrestrial and IP-based services. TELEVISION (TV) services transmitted in a Digital Terrestrial Television (DTT) network can be classified depending on their target area. Global services target the services of the users throughout the network and local services are referred to the services which are relevant to users of certain sub- regions.
Conclusion
The efficient provision of local services in SFNs with minimum increased overhead was one of the commercial requirements underlying DVB-NGH. This paper has analyzed the implementation issues and evaluated the performance in terms of minimum CNR required for successful decoding and capacity gain of the two complementary technical solutions adopted, known as H-LSI (based on hierarchical modulation) and O-LSI (using orthogonal transmission mode). We first reviewed the benefits that can be exploiting by the utilization of MIMO techniques and provided capacity results that showed a potential gain in spectral efficiency compared to single antenna