tailieunhanh - Survey of admission control in IEEE 802.11e wireless LANs

The purpose of admission control is to limit the amount of traffic admitted into a particular service class so that the QoS of the existing flows will not be degraded, while at the same time the medium resources can be maximally utilized | Survey of admission control in IEEE wireless LANs 報告人：李宗穎 Outline Introduction Background for IEEE Admission Control for IEEE Conclusion Introduction (1/2) standard provides a very powerful platform for QoS supports in WLANs This report provide an extensive survey of advances in admission control algorithms/protocols in IEEE WLANs Introduction (2/2) The purpose of admission control is to limit the amount of traffic admitted into a particular service class so that the QoS of the existing flows will not be degraded, while at the same time the medium resources can be maximally utilized Background for EDCA (enhanced distributed channel access) Contention based HCCA (HCF controlled channel access) Centralized control NOT much research work on the admission control issue in HCCA Background for EDCA mode Admission Control Research Admission Control for EDCA Measurement-based Model-Based Admission Control for HCCA Do NOT covered in this report Distributed Admission Control (1/2) Step 1 : via beacons the QAP announces the transmission budget Step 2 : measure the amount of time occupied by the transmission of each AC during each beacon interval transmission budget for an AC is depleted new flow will not be able to obtain any transmission time existing flows will not be able to increase their transmission time [ref.] Y. Xiao and H. Li, “Evaluation of Distributed Admission Control for the IEEE EDCA,” IEEE Commun. Mag., vol. 42, no. 9, 2004, pp. S20–S24. [ref.] Y. Xiao and H. Li, “Voice and Video Transmissions with Global Data Parameter Control for the IEEE Enhance Distributed Channel Access,” IEEE Trans. Parallel Distrib. Sys., vol. 15, no. 11, 2004, pp. 1041–53. Distributed Admission Control (2/2) Shortcoming it is difficult to avoid network performance vibration because a station always adjusts its transmission parameters at every beacon interval this scheme . | Survey of admission control in IEEE wireless LANs 報告人：李宗穎 Outline Introduction Background for IEEE Admission Control for IEEE Conclusion Introduction (1/2) standard provides a very powerful platform for QoS supports in WLANs This report provide an extensive survey of advances in admission control algorithms/protocols in IEEE WLANs Introduction (2/2) The purpose of admission control is to limit the amount of traffic admitted into a particular service class so that the QoS of the existing flows will not be degraded, while at the same time the medium resources can be maximally utilized Background for EDCA (enhanced distributed channel access) Contention based HCCA (HCF controlled channel access) Centralized control NOT much research work on the admission control issue in HCCA Background for EDCA mode Admission Control Research Admission Control for EDCA Measurement-based Model-Based Admission .