Round Robin Packet Scheduler Research Articles

A Dynamic Round-Robin Packet Scheduling Algorithm

This paper puts forward a new dynamic round-robin (DYRR) packet scheduling algorithm with high efficiency and good fairness. DYRR algorithm introduces dynamic round-robin concept, that is, the allowance given to each of the flows in a given round is not fixed, but is related with the number of bytes sent of this and other flows of the last round scheduling. The time complexity of the DYRR algorithm is O(1). Results from performance simulation analysis shows that DYRR algorithm can effectively smooth output burst, realize fair scheduling, and have a good time delay characteristic.

Amplify-and-forward cooperation under interference-limited spatial reuse of the relay slot

Cooperative transmission has emerged as an effective tool to deal with channel impairments. In this work we study the applicability of amplify-and-forward cooperative transmission in the downlink of a TDMA cellular system where idle terminals act as relays. The base station may have a multiple antenna configuration, whereas all terminals are equipped with a single antenna. Although cooperation can be viewed as a virtual MIMO system, it further allows dealing with shadowing and pathloss. In order to improve the spectral efficiency loss incurred by the half-duplex relays, in this work we consider the reuse of the relay time slot by simultaneous transmissions from the active relays in the cell. We are able to model the interfering power received by each destination in that slot. The only system parameters adjusted to control the interference are the number of interfering relay terminals and a cell-wide .target SNR in the relay-destination link. This way, it is shown that cooperative transmission is able to provide significant gains in terms of throughput over the direct transmission under round-robin packet scheduling and uniform distribution of terminals by controlling the rate of each transmission (rate control).

Performance evaluation of prioritized scheduling with buffer management for differentiated services architectures

Differentiated services (DiffServ) is an architecture for the Internet in which various applications are supported using a simple classification scheme. Packets entering the DiffServ domain are marked depending on the packets' class. In this paper we introduce a versatile service and buffering scheme for different classes in a differentiated services Internet. The objective of this scheme is to introduce relative differentiation in terms of mean delay, throughput. In this scheme both high-buffer-priority (HPC) and low-buffer-priority (LPC) classes have reserved buffers. In addition, they have a shared buffer, where the priority of the shared buffer occupancy is to HPC traffic. Service priorities can be for high-buffer-priority traffic, low-buffer-priority traffic or round robin. An exact performance model for the proposed scheme is introduced. The performance model represents HPC and LPC traffic arrivals by a discrete batch Markov arrival process (D-BMAP). The model is used to obtain loss ratios, packet delays and throughputs for both HPC and LPC traffic. Performance results show that implementing buffer priorities, with a weighted round robin packet scheduling policy, results in low packet loss ratio and/or delay for the high-priority class without starving the low-priority class.

An Improved Round Robin Packet Scheduler for Wireless Networks

Scheduling algorithms are important components for providing quality-of-service (QoS) guarantees in wireless networks. The design of such algorithms need to take into account bursty errors and location-dependent channel capacity that are characteristics of wireless networks. In this paper, a new scheduling algorithm for packet cellular networks, wireless deficit round robin (WDRR), is proposed. WDRR is a round robin scheduler that has low implementation complexity and offers a low delay bound, tight fairness index, and good isolation property. In error-prone channels, the algorithm provides short-term fairness among sessions that perceive a clean channel, long-term fairness among all sessions, ability to meet specified throughput objectives for all sessions, and graceful service degradation among sessions that received excess service. Both analysis and simulation are used to verify the WDRR properties.