Scheduling of Real-time and Nonreal-time Traffics in IEEE 802.11 Wireless LAN

무선랜에서의 실시간 및 비실시간 트래픽 스케줄링

  • Published : 2003.06.01

Abstract

Media Access Control (MAC) Protocol in IEEE 802.11 Wireless LAN standard supports two types of services, synchronous and asynchronous. Synchronous real-time traffic is served by Point Coordination Function (PCF) that implements polling access method. Asynchronous nonreal-time traffic is provided by Distributed Coordination Function (DCF) based on Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA) protocol. Since real-time traffic is sensitive to delay, and nonreal-time traffic to error and throughput, proper traffic scheduling algorithm needs to be designed. But it is known that the standard IEEE 802.11 scheme is insufficient to serve real-time traffic. In this paper, real-time traffic scheduling and admission control algorithm is proposed. To satisfy the deadline violation probability of the real time traffic the downlink traffic is scheduled before the uplink by Earliest Due Date (EDD) rule. Admission of real-time connection is controlled to satisfy the minimum throughput of nonreal-time traffic which is estimated by exponential smoothing. Simulation is performed to have proper system capacity that satisfies the Quality of Service (QoS) requirement. Tradeoff between real-time and nonreal-time stations is demonstrated. The admission control and the EDD with downlink-first scheduling are illustrated to be effective for the real-time traffic in the wireless LAN.

Keywords

References

  1. Wireless : Merging onto the Information Superhighway, Sixth IEEE International Symposium v.2 Voice and data transmission over an 802.11 wireless network A.Visser;E.Zarki
  2. 1999 IEEE International Workshop on Mobile Multimedia Communications Measurement of Characteristics of Voice over IP in a Wireless LAN J.Feigin;K.Pahlavan
  3. IEEE Communications Magazine v.35 IEEE 802.11 wireless local area networks B.P.Crow;I.Widjaja;L.G.Kim;P.T.Sakai
  4. GLOBECOM'99 v.1b Performance evaluation of integrated video and data transmission with the IEEE 802.11 standard MAC protocol T.Suzuki;S.Tasaka
  5. VTC 1999 v.5 Performance comparison of voice over IEEE 8023.11 chemes R.Prasad
  6. Wireless Networks Scheduling of real-time traffic in IEEE 802.11 wireless LANs C.Coutras;S.Gupta;N.B.Shroff
  7. IEEE Standard 802.11-1997 Information Technoloty-Telcommunications And Information exchange Between Systems-Local And Metropolitan Area Networks-Specific Requirement-part 11 : Wireless LAN Medium Access Control (MAC) And Physical Layer (PHY) Specifications
  8. Delivering voice over IP networks D.Minoli;E.Minoli
  9. IEEE/AMC Trans on Networking v.4 no.3 Efficient Fair Queuing Using Deficit Round Robin M.Shreedhar;G.Varghese https://doi.org/10.1109/90.502236
  10. IEEE International Conference on Networks (ICON '99) Impact of polling strategy on capacity of 802.11 based wireless multimedia LANs R.S.Ranasinghe;L.L.H.Andrew;D.Everitt
  11. Journal of the Association for Computing Machinery v.20 no.1 Scheduling Algorithms for Multiprogramming in a Hard-Real-Time Evironment C.L.Liu;J.W.Layland https://doi.org/10.1145/321738.321743
  12. IEEE/ACM Transactions on Networking v.8 no.Issue 1 A Unified Wireless LAN Architecture for Real-time and Non-real-time Communication Services S.Choi;K.G.Shin https://doi.org/10.1109/90.836477
  13. GLOBECOM '00 v.1 A new scheduling mechanism to provide relative differentiation for real-time IP traffic S.Bodamer
  14. IEEE/AMC Transactions Networking v.8 no.6 Dynamic tuning of the IEEE 802.11 protocol to achieve a theoretical throughput limit F.Cali;M.Conit;E.Gregori https://doi.org/10.1109/90.893874
  15. IEEE Standard 802.11b-1999 Information Technology - Telecommunications And Information Exchange Between Systems-Local And Metropolitan Area Networks-Specific Requirments-Part 11 : Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) Specifications