Efficient Resource Management Mechanism for 802.16 Wireless Networks Based on Weighted Fair Queuing

Wireless Networking continues on its path of being one of the most commonly used means of communication. The evolution of this technology has taken place through the design of various protocols. Some common wireless protocols are the WLAN, 802.16 or WiMAX, and the emerging 802.20, which specializes in high speed vehicular networks, taking the concept from 802.16 to higher levels of performance. As with any large network, congestion becomes an important issue. Congestion gains importance as more hosts join a wireless network. In most cases, congestion is caused by the lack of an efficient mechanism to deal with exponential increases in host devices. This can effectively lead to very huge bottlenecks in the network causing slow sluggish performance, which may eventually reduce the speed of the network. With continuous advancement being the trend in this technology, the proposal of an efficient scheme for wireless resource allocation is an important solution to the problem of congestion. The primary area of focus will be the emerging standard for wireless networks, the 802.16 or “WiMAX”. This project, attempts to propose a mechanism for an effective resource management mechanism between subscriber stations and the corresponding base station

Minimizing the Message Waiting Time in Single-Hop Multichannel Systems

In this paper, we examine the problem of packet scheduling in a single-hop multichannel systems, with the goal of minimizing the average message waiting time. Such an objective function represents the delay incurred by the users before receiving the desired data. We show that the problem of finding a schedule with minimum message waiting time, is NP-complete, by means of polynomial time reduction of the time table design problem to our problem. We present also several heuristics which result in outcomes very close to the optimal ones. We compare these heuristics by means of extensive simulations

Minimum Message Waiting Time Scheduling in Distributed Systems

In this paper, we examine the problem of packet scheduling in a single-hop multichannel system, with the goal ofminimizing the average message waiting time. Such an objective function represents the delay incurred by the users before receivingthe desired data. We show that the problem of finding a schedule with minimum message waiting time is NP-complete, by means ofpolynomial time reduction of the time table design problem to our problem. We present also several heuristics that result in outcomesvery close to the optimal ones. We compare these heuristics by means of extensive simulations

Optimizing resource allocation in next-generation optical access networks

To meet rapidly increasing traffic demands caused by the popularization of Internet and the spouting of bandwidth-demanding applications, Passive Optical Networks (PONs) exploit the potential capacities of optical fibers, and are becoming promising future-proof access network technologies. On the other hand, for a broader coverage area and higher data rate, integrated optical and wireless access is becoming a future trend for wireless access. This thesis investigates three next-generation access networks: Time Division Multiplexing (TDM) PONs, Wavelength Division Multiplexing (WDM) PONs, and WDM Radio-Over-Fiber (RoF) Picocellular networks. To address resource allocation problems in these three networks, this thesis first investigates respective characteristics of these networks, and then presents solutions to address respective challenging problems in these networks. In particular, three main problems are addressed: arbitrating time allocation among different applications to guarantee user quality of experience (QoE) in TDM PONs, scheduling wavelengths optimally in WDM PONs, and jointly allocating fiber and radio resources in WDM RoF Picocellular networks. In-depth theoretical analysis and extensive simulations have been performed in evaluating and demonstrating the performances of the proposed schemes