tailieunhanh - Báo cáo hóa học: " Research Article Opportunistic Adaptive Transmission for Network Coding Using Nonbinary LDPC Codes"

Tuyển tập báo cáo các nghiên cứu khoa học quốc tế ngành hóa học dành cho các bạn yêu hóa học tham khảo đề tài: Research Article Opportunistic Adaptive Transmission for Network Coding Using Nonbinary LDPC Codes | Hindawi Publishing Corporation EURASIP Journal on Wireless Communications and Networking Volume 2010 Article ID517921 15 pages doi 2010 517921 Research Article Opportunistic Adaptive Transmission for Network Coding Using Nonbinary LDPC Codes Giuseppe Cocco Stephan Pfletschinger Monica Navarro and Christian Ibars Centre Tecnol Ogic de Telecomunicacions de Catalunya 08860 Castelldefels Spain Correspondence should be addressed to Giuseppe Cocco Received 31 December 2009 Revised 14 May 2010 Accepted 3 July 2010 Academic Editor Wen Chen Copyright 2010 Giuseppe Cocco et al. This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use distribution and reproduction in any medium provided the original work is properly cited. Network coding allows to exploit spatial diversity naturally present in mobile wireless networks and can be seen as an example of cooperative communication at the link layer and above. Such promising technique needs to rely on a suitable physical layer in order to achieve its best performance. In this paper we present an opportunistic packet scheduling method based on physical layer considerations. We extend channel adaptation proposed for the broadcast phase of asymmetric two-way bidirectional relaying to a generic number M of sinks and apply it to a network context. The method consists of adapting the information rate for each receiving node according to its channel status and independently of the other nodes. In this way a higher network throughput can be achieved at the expense of a slightly higher complexity at the transmitter. This configuration allows to perform rate adaptation while fully preserving the benefits of channel and network coding. We carry out an information theoretical analysis of such approach and of that typically used in network coding. Numerical results based on nonbinary LDPC codes confirm the effectiveness of our approach with respect to