Due to the increase of users the efficient usage of spectrum plays an important role in digital terrestrial television networks. In digital video broadcasting, local and global content are transmitted by single frequency network and multifrequency network respectively. Multifrequency network support transmission of global content and it consumes large spectrum. Similarly local content are well ...

Hierarchical modulation multiplexes layers of different robustness into one stream. Usually being exploited in broadcast systems such as digital video broadcasting, hierarchical modulation can also be applied to unicast communications in a cooperative manner. This article deals with novel multi-hop cooperative transmission and routing strategies with hierarchical modulation. In multi-hop networ...

Broadcasting systems have to deal with channel variability in order to offer the best rate to the users. Hierarchical modulation is a practical solution to provide different rates to the receivers in function of the channel quality. Unfortunately, the performance evaluation of such modulations requires time consuming simulations. We propose in this paper a novel approach based on the channel ca...

OF THE MASTER’S THESIS Author: Gao Liang Title: Hierarchical MIMO modulation in digital TV transmission Date: September 2009 Number of pages: 76 Faculty: Electronics, Communications and Automation Professorship: S-72 Communications Engineering Supervisor: Professor Olav Tirkkonen It is possible to use hierarchical modulation in broadcast systems so that there are two different levels of service...

We study variable node degree distributions resulting from a linear programming approach for designing a lowdensity parity-check (LDPC) code optimized for an irregular modulation alphabet. We opt for an irregular LDPC code and make use of the irregularities of the channel in the sense of different modulation classes originating especially from different distances in a hierarchical modulation si...