Authors: K. Chandrakala; J. Jayakumari
Addresses: Department of Electronics and Communication Engineering, Noorul Islam Centre for Higher Education, Tamil Nadu, India ' Department of Electronics and Communication Engineering, Mar Baselios College of Engineering and Technology, Kerala, India
Abstract: In digital video broadcasting either multi-frequency or single frequency network is used to transmit local and global broadcasting contents respectively. Multi-frequency network consumes large spectrum to transmit local information alone. Therefore an efficient technique is required to embed both local and global content in single constellation. In this paper, hierarchical modulation or multilayered modulation is employed to satisfy this requirement in which the task is achieved by layered constellation. The base layer carries the high priority global contents and the low priority information is carried by the enhancement layer. The performance of the system is highly determined by the detection rules and the coder chosen. The performance of hierarchical modulation system is analysed by framing decision rules for both high priority and low priority streams. In addition to derivation of probability of error of the system, the analysis of bit error rate of coded and uncoded system is done. Convolutional encoder with code rate 1/3, 1/2 and 2/3 is used in this paper.
Keywords: single frequency network; multi-frequency network; QPSK; QAM hierarchical modulation; multilayer modulation; digital video broadcasting.
International Journal of Wireless and Mobile Computing, 2019 Vol.16 No.1, pp.72 - 79
Available online: 16 Jan 2019 *Full-text access for editors Access for subscribers Purchase this article Comment on this article