Channel Efficiency Aware Scheduling Algorithm for Real-Time Services in Wireless Networks

In this paper, we consider the problem of scheduling real time services over time-varying wireless links in broad-band wireless networks where an Adaptive Modulation and Coding (AMC) scheme is applied in the physical layer in order to decrease the packet error rate. It is well known that a properly chosen modulation and coding scheme can increase error robustness in the physical layer. However, this is at the expense of higher system complexity and decreased channel efficiency. We present a novel Near Maximum Weighted Bipartite Matching (NMWBM) scheduling algorithm, which schedules real time services in accordance with delay bounds and phys-cal layer modulation and coding modes. Numerical results set in the context of IEEE 802.16 networks show that NMWBM can improve system packet throughput and pro-vide higher channel efficiency compared to the existing Earliest Deadline First scheduling algorithm. NMWBM provides this improved performance while meeting delay bound and packet loss rate requirements of real time ser-vices in broadband wireless networks

Quality of service support in differentiated services packet networks

During the past few years, new types of Internet applications which require performance beyond the best-effort service that is provided by the current Internet have emerged. These applications include the transmission of voice and video, which require a fixed end-to-end delay bound in order for the end-user to perceive an acceptable level of service quality. The Differentiated Services (Diffserv) model has been proposed recently to enhance the traditional best-effort service, and provide certain Quality of Serviee (QoS) guarantees to these applications. Its current definition, however, does not allow for a high level of flexibility or assurance and, therefore, it can not be widely deployed. In this paper, we introduce a new protocol for a Diffserv architecture which provides a simple and efficient solution to the above problem. It is a complete protocol, in the sense that it deals with the issues of packet scheduling, admission control, and congestion control. We will show, through experimental results, that our proposed protocol can improve the flexibility and assurance provided by current solutions, while maintaining a high level of network utilization.published_or_final_versio

Profit-oriented resource allocation using online scheduling in flexible heterogeneous networks

In this paper, we discuss a generalized measurement-based adaptive scheduling framework for dynamic resource allocation in flexible heterogeneous networks, in order to ensure efficient service level performance under inherently variable traffic conditions. We formulate our generalized optimization model based on the notion of a “profit center” with an arbitrary number of service classes, nonlinear revenue and cost functions and general performance constraints. Subsequently, and under the assumption of a linear pricing model and average queue delay requirements, we develop a fast, low complexity algorithm for online dynamic resource allocation, and examine its properties. Finally, the proposed scheme is validated through an extensive simulation study.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/47990/1/11235_2006_Article_6525.pd

Transform-domain analysis of packet delay in network nodes with QoS-aware scheduling

In order to differentiate the perceived QoS between traffic classes in heterogeneous packet networks, equipment discriminates incoming packets based on their class, particularly in the way queued packets are scheduled for further transmission. We review a common stochastic modelling framework in which scheduling mechanisms can be evaluated, especially with regard to the resulting per-class delay distribution. For this, a discrete-time single-server queue is considered with two classes of packet arrivals, either delay-sensitive (1) or delay-tolerant (2). The steady-state analysis relies on the use of well-chosen supplementary variables and is mainly done in the transform domain. Secondly, we propose and analyse a new type of scheduling mechanism that allows precise control over the amount of delay differentiation between the classes. The idea is to introduce N reserved places in the queue, intended for future arrivals of class 1

コウコウリツカ コンピュータ ツウシン システム ニ カンスル ケンキュウ

博士(工学)大阪市立大