Ho-Ting Wu

Modern access networks are constructed widely by passive optical networks (PONs) to meet the growing bandwidth demand. However, higher bandwidth means more energy consumption. To save energy, a few research works propose the dual-mode energy saving mechanism that allows the ONU to operate between active and sleep modes periodically. However, such dual-mode energy saving design may induce unnecessary power consumption or packet delay increase in the case where only downstream data exist for most of the time. In this paper, we propose a new tri-mode energy saving scheme for Ethernet PON (EPON). The new tri-mode energy saving design, combining the dual-mode saving mechanism with the doze mode, allows the ONU to switch among these three modes alternatively. In the doze mode, the ONU may receive downstream data while keeping its transmitter close. Such scenario is often observed for real time video downstream transmission. Furthermore, the low packet delay of high priority upstream data can be attained through the use of early wake-up mechanism employed in both energy saving modes. The energy saving and system efficiency can thus be achieved jointly while maintaining the differentiated QoS for data with various priorities. Performance results via simulation have demonstrated the effectiveness of such mechanism. © (2015) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.

This paper proposes a new switching architecture to be used in all optical packet switching networks. The proposed switch is derived from an original 2 × ?2 two‐stage multi‐buffer switched delay line based optical switching node, known as an M‐Quadro node. By incorporating bypass lines into the M‐Quadro architecture and employing a novel switch control strategy, the optical packet switching node can effectively resolve packet contentions, thus reducing the packet deflection probability substantially. Furthermore, we show that such architecture is scalable for a generic multiple stages optical packet switch with a larger number of input/output ports.

Universal Mobile Telecommunication System (UMTS) uses wideband CDMA (WCDMA) radio access technique that supports quantized-bandwidth allocation mechanism. In such system, if the power density of a spread signal is much lower than that of the background noise, the recovery of the original signal may be impossible. Therefore, we need an admission control policy to grant the users' access to the system and to achieve high system utilization simultaneously. This paper addressed the problem of determining admission control policy for UMTS with a finite background noise constraint. We applied semi-Markov decision process (SMDP) theory to build the model of resource allocation and find the optimal policy by linear programming (LP). The results showed that the policy we found can achieve high utilization and low blocking probability

Ethernet passive optical networks (EPON) is being considered as promising solution for next-generation broadband access network. EPON has the features of low-cost Ethernet deployment and highspeed optical connections. The mission of IEEE 802.ah Task Force is to construct a solid structure for deployment where it defines the multi point control protocol (MPCP) and leaves details of dynamic bandwidth allocation (DBA) for vendors and researchers. ONU and OLT exchange REPORT and GATE messages to coordinate the transmission time and bandwidth allocation fro upstream traffic. Quality of service (QoS) is one of the main features required in EPON. Delay-sensitive applications, such as VoIP, video streaming, should be taken care. In this paper, we will investigate the ideas of predictive credit mechanism in EPON. If a suitable credit is assigned, some packets won't have to wait another cycle time to get transmitted. We have found that the packet delay can be shorter by sacrificing a little bandwidth in some scenarios. We have shown and proposed several predictive credit mechanisms and compared them to the mechanism without prediction