Queue Scheduling Scheme Research Articles

Design and Implementation of Low Latency Weighted Round Robin (LL-WRR) Scheduling for High Speed Networks

Today’s wireless broadband networks are required to provide QoS guarantee as well as fairness to different kinds of traffic. Recent wireless standards (such as LTE and WiMAX) have special provisions at MAC layer for differentiating and scheduling data traffic for achieving QoS. The main focus of this paper is concerned with high speed packet queuing/scheduling at central node such as base station (BS) or router to handle network traffic. This paper proposes novel packet queuing scheme termed as Low Latency Weighted Round Robin (LL-WRR) which is simple and effective amendment to weighted round robin (WRR) for achieving low latency and improved fairness. Proposed LL-WRR queue scheduling scheme is implemented in NS-2 considering IEEE 802.16 network [1] with real time video and Constant Bit Rate (CBR) audio traffic connections. Simulation results show improvement obtained in latency and fairness using LL-WRR. The proposed scheme introduces extra complexity of computing coefficient but its overall impact is very small.

Maximum Average Service Rate and Optimal Queue Scheduling of Delay-Constrained Hybrid Cognitive Radio in Nakagami Fading Channels

As a promising technique to improve achievable bandwidth efficiency, cognitive radio (CR) has attracted substantial research attention from both the academic and industrial communities. To improve the performance attained by the secondary user (SU), a novel hybrid CR system is proposed, which combines the conventional interweave and underlay paradigms to enhance the chance of the SU to access the spectrum. Queuing theory is invoked in this paper to analyze the impact of the primary user's maximum tolerable delay on the performance of the SU. Multiple queues are assumed for the SU, which is engaged in video communication. Apart from the Poisson traffic generation, we also model the classic Nakagami-m fading channel as a Poisson service process by utilizing the outage probability in the presence of cochannel interference. We optimize the hybrid interweave/underlay procedure to maximize the average service rate μS, max of the SU, as well as the queue's scheduling scheme, for the sake of minimizing the overall average delay (OAD). As a result, the OAD of the SU is reduced by up to 27% and 20%, compared with the proportion and round-robin schemes, respectively.

Fuzzy-Based Dynamic Distributed Queue Scheduling for Packet Switched Networks

Addressing the problem of queue scheduling for the packet-switched system is a vital aspect of congestion control. In this paper, the fuzzy logic based decision method is adopted for queue scheduling in order to enforce some level of control for traffic of different quality of service requirements using predetermined values. The fuzzy scheduler proposed in this paper takes into account the dynamic nature of the Internet traffic with respect to its time-varying packet arrival process that affects the network states and performance. Three queues are defined, viz low, medium and high priority queues. The choice of prioritizing packets influences how queues are served. The fuzzy scheduler not only utilizes queue priority in the queue scheduling scheme, but also considers packet drop susceptibility and queue limit. Through simulation it is shown that the fuzzy scheduler is more appropriate for the dynamic nature of Internet traffic in a packet-switched system as compared with some existing queue scheduling methods. Results show that the scheduling strategy of the proposed fuzzy scheduler reduces packet drop, provides good link utilization and minimizes queue delay as compared with the priority queuing (PQ), first-in-first-out (FIFO), and weighted fair queuing (WFQ).