Integrating Optical Wireless Services at the Access NetworkAuthors: Yuanqiu Luo, Ting Wang, Steve Weinstein, NEC Laboratories America; Milorad Cvijetic, NEC America, Inc.With the expansion of services offered over the Internet, a dramatic increase of bandwidth has been facilitated both in the backbone network and the local area network (LAN). Such a growing gap results in the serious bottleneck of the access network in between. It is desired to upgrade the current access network technologies to provide end users with low-cost and high-speed broadband access services. Optical fiber technology is considered as an attractive wired solution, and Worldwide interoperability for microwave access (WiMAX) is the promising wireless counterpart.Purposing to combine the benefits of optical fiber capacity and wireless mobility together, we propose a new architecture to integrate optical and wireless technologies at the access network. Compared with the current access technologies, such as DSL and Cable Modem, the benefits of such integration include higher bandwidth, longer service penetration, and compatibility with the FTTx deployment. Most important of all, the centralized management of optical and wireless transmission at the central office increases system capacity by employing dynamical network resource allocation between the optical and wireless part, and thus relaxing the tedious effort of radio frequency reuse planning and providing higher utilization.Several optical wireless integration cases at the access network are also proposed, among which two are of high interests to the service providers. The "optical fiber and WiMAX integration" uses the existing optical fiber connections to the neighborhood, and WiMAX antenna is employed at the end of optical fiber to deliver broadband services. The "PON and WiMAX integration" is compatible with the rapidly deployed PON architecture. It embeds WiMAX antennas at the optical network units (ONUs) to support wireless transmission.The integrated network performance has been evaluated from experiments using the OPNET Modeler network simulator. Performance metrics include the network throughput and the end-to-end packet delay of data, voice, and video services, respectively. Results from simulations show that the optical wireless integration increases access network capacity, promotes end user mobility, and the centralized management at the edge node decreases the access point complexity. The results also demonstrate that the "optical fiber and WiMAX integration" is a viable solution to the access network. It performs the best with respect to both throughput and end-to-end delays. The "PON and WiMAX integration" presents satisfactory network performance, implying that it is a low-cost alternative option to the access network.

© 2006 Optical Society of America

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