WSEAS CONFERENCES. WSEAS, Unifying the Science

Main Page of the Journal                      All 2008                        Main Page of the WSEAS

Oct. 2007, Nov. 2007, Dec. 2007, 2008


Issue 10, Volume 6, October 2007
Print ISSN: 1109-2742
E-ISSN: 2224-2864








Title of the Paper:  Performance of Wideband Mobile Channel on Synchronous DS-CDMA


Authors: Hamed D. Al-Sharari

Abstract: Direct-sequence code-division multiple access (DS-CDMA) is currently the subject of much research as it is a promising multiple access capability for third and fourth generations mobile communication systems. The synchronous DS-CDMA system is well known for eliminating the effects of multiple access interference (MAI) which limits the capacity and degrades the BER performance of the system. In this paper, we investigate the bit error rate (BER) performance of a synchronous DS-CDMA system over a wideband mobile radio channel. The BER performance is affected by the difference in path length ΔL and the number of arriving signals N. Furthermore, the effect of these parameters is examined on the synchronous DS-CDMA system for different users’ number as well as different processing gain Gp. The promising simulation results showed the possibility of applying this system to the wideband mobile radio channel.

Keywords: Effect, Gain, Wideband, Synchronous, Direct –sequence, CDMA, BER.

Title of the Paper: Vulnerabilities and Security Strategy for the Next Generation Bandwidth Elastic PON


Authors: Stamatios V. Kartalopoulos, Di Jin

Abstract: The next generation WDM/TDM-PON is scalable and delivers elastically ultra-high data rates to many thousands of end-users, and therefore network security becomes of particular importance. We identify different levels of security and responsibilities in the communications network, we identify vulnerabilities in the optical access network and we describe the security features, monitoring and detecting of the next generation PON network.

Keywords: Optical Networks, PON, FTTH, Network Security

Title of the Paper: A Proxy Caching System for MPEG-4 Video Streaming with a Quality Adaptation Mechanism


Authors: Yoshiaki Taniguchi, Naoki Wakamiya and Masayuki Murata

Abstract: In this paper, we propose, design, implement, and evaluate a proxy caching system for MPEG- 4 video streaming services for heterogeneous users. In our system, a video stream is divided into blocks for efficient use of the cache buffer and the bandwidth. A proxy retrieves a block from a server, deposits it in its local cache buffer, and provides a requesting client with the block in time. It maintains the cache with limited capacity by replacing unnecessary cached blocks with a newly retrieved one. It also prefetches video blocks that are expected to be required in the near future. In addition, the proxy server adjusts the quality of block appropriately, because clients are heterogeneous, in terms of the available bandwidth, end-system performance, and so on. Through evaluations, we proved that our proxy caching system could provide users with a continuous and high-quality video streaming service in a heterogeneous environment.

Keywords: video streaming service, proxy caching, quality adaptation, MPEG-4, prototype, evaluation

[Journals], [Books], [Conferences], [Research], [Contact us], [Indexing], [Reports], [E-Library], [FAQ],
[Upcoming Conferences with Expired Deadline], [History of the WSEAS Conferences]

Copyright © WSEAS