tailieunhanh - Báo cáo hóa học: " Research Article A New OFDMA Scheduler for Delay-Sensitive Traffic Based on Hopfield Neural Networks"

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 A New OFDMA Scheduler for Delay-Sensitive Traffic Based on Hopfield Neural Networks | Hindawi Publishing Corporation EURASIP Journal on Wireless Communications and Networking Volume 2008 Article ID 817676 9 pages doi 2008 817676 Research Article A New OFDMA Scheduler for Delay-Sensitive Traffic Based on Hopfield Neural Networks Nuria García 1 Jordi Perez-Romero 2 and Ramon Agusti2 1 Grup de Recerca en Tecnologies i Estrat egies de les Telecomunicacions Departament de Tecnologies de la Informacio i les Comunicacions Universitat Pompeu Fabra Passeigde 8 08003 Barcelona Spain 2 Grup de Recerca en Comunicacions Mòbils Departament de Teoria del Senyal i Comunicacions Universitat Politecnica de Catalunya C Jordi Girona 31 08034 Barcelona Spain Correspondence should be addressed to Jordi Perez-Romero jorperez@ Received 1 May 2007 Revised 6 November 2007 Accepted 4 January 2008 Recommended by Luc Vandendorpe This paper introduces a novel joint channel and queuing-aware OFDMA scheduler for delay-sensitive traffic based on a hopfield neural network HNN scheme. It allows providing an optimum OFDMA performance by solving a complex combinational problem. The algorithm is based on distributing the available subcarriers among the users depending on the one hand on the time left for the transmission of the different packets in due time so that packet droppings are avoided. On the other hand it also accounts for the available channel capacity in each subcarrier depending on the channel status reported by the different users. The different requirements are captured in the form of an energy function that is minimized by the algorithm. In that respect the paper illustrates two different algorithms coming from two settings of this energy function. The algorithms have been evaluated for delay-sensitive traffic and they have been compared against other state-of-the-art algorithms existing in the literature exhibiting a better behavior in terms of packet-dropping probability. Copyright 2008 Nuria García et al. This is an open access .