Distributed fair scheduling in a wireless LAN
MobiCom '00 Proceedings of the 6th annual international conference on Mobile computing and networking
Priority scheduling in wireless ad hoc networks
Proceedings of the 3rd ACM international symposium on Mobile ad hoc networking & computing
Distributed priority scheduling and medium access in ad hoc networks
Wireless Networks
Evaluation of Quality of Service Schemes for IEEE 802.11 Wireless LANs
LCN '01 Proceedings of the 26th Annual IEEE Conference on Local Computer Networks
MSWIM '03 Proceedings of the 6th ACM international workshop on Modeling analysis and simulation of wireless and mobile systems
A Practical Layer 3 Admission Control and Adaptive Scheduling (L3-ACAS) for COTS WLANs
Wireless Personal Communications: An International Journal
| Hi-index | 0.00 |
In IEEE 802.11e Enhanced Distributed Coordinator Function (EDCF) (In the recently approved IEEE 802.11e standard, EDCF is renamed to enhanced distributed channel access (EDCA). Throughout this paper, we use EDCF for consistency with early work in the literature.), per-flow service differentiation is achieved by maintaining separate queues for different traffic categories (TCs). However, due to its static Quality of Service (QoS) parameter setting, EDCF does not perform adequately under high traffic load (Romdhani et al., Proceedings of IEEE wireless communications and networking conference, 2003). We present an extended performance model of EDCF and analyze conditions for network getting overloaded. With this extended model, we show that the overall throughput of a network can be improved by changing the distribution of the number of active stations (an active station is one that has a pending packet to be sent) over a set of TCs. Hence, we propose to dynamically re-allocate flow priorities evenly in order to maintain high system performance while providing QoS guarantee for individual real-time flows. Our scheme has several interesting features: (1) performance of EDCF is improved; (2) low priority flows are not starved under high traffic load; (3) misuse of priority (misuse of priority means that a flow requests much higher priority than necessary) can be easily handled. Simulations are conducted for both infrastructure-based and Ad hoc models. Results show that dynamic priority re-allocation does not decrease throughput of real-time flows under low to medium loads, while considerable improvement over EDCF is obtained even under high loads, making it easy to support multimedia applications.