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Throughput and fairness in a hybrid channel access scheme for ad hoc networks

Throughput and fairness in a hybrid channel access scheme for ad hoc networks. Yu Wang and J.J. Garcia-Luna-Aceves IEEE WCNC 2003 Speaker ： earl. Outline. Introduction Related Work Hybrid channel access scheme Simulation Conclusion References. Introduction.

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Throughput and fairness in a hybrid channel access scheme for ad hoc networks

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  1. Throughput and fairness in a hybrid channel access scheme for ad hoc networks Yu Wang and J.J. Garcia-Luna-Aceves IEEE WCNC 2003 Speaker：earl

  2. Outline • Introduction • Related Work • Hybrid channel access scheme • Simulation • Conclusion • References earl

  3. Introduction • To design an adaptive channel access scheme that makes use of both sender-initiated and receiver-initiated handshakes • Sender-initiated:use collision avoidance handshake (RTS,CTS,data,ACK) • Receiver-initiated:to poll its neighbors actively to see if they have packets for itself earl

  4. Related Work • The first receiver-initiatedMAC protocol [3] F. Talucci and M. Gerla, “MACA-BI (MACA by Invitation): A ReceiverOriented Access Protocol for Wireless Multihop Networks,” in Proc. OfPIMRC ’97, 1997 earl

  5. Related Work • Receiver-initiated schemes with proper collision avoidance procedures can outperformsender-initiated schemes due to reduced overhead of control packets [4] • [4] J. J. Garcia-Luna-Aceves and A. Tzamaloukas, “Receiver-initiated Collision Avoidance in Wireless Networks,” ACM Wireless Networks, vol. 8, pp. 249–263, 2002. earl

  6. Related Work • Fairness problem • The scheme 1 try to reduce the ratio between maximum throughput and minimum throughput of flows[6,10,11] • The scheme 2 used in fair queueing for wireline networks is adapted to multi-hop ad hoc networks [7–9, 12, 13] earl

  7. Hybrid channel access scheme • Collision-free RIMA protocol [4] • Introduce new types control packets (No-transmission-Request) • Enforce various collision-avoidance waiting periods • HCAS (hybrid channel access scheme) protocol • Only CTS packet is used as the polling packet • Use network allocation vector (NAV) earl

  8. Hybrid channel access scheme • A node operates alternately in two modes: • Sender-initiated (SI) : four-way RTS-CTS-data-ACK handshake is used in the SI mode • Receive-initiated (RI) : three-way CTS-data-ACK handshake is used in the RI mode earl

  9. HCAS-Sender The same RTS packet for more than one half of the times allowed in the IEEE802.11 MAC protocol Gets no response from the intended receiver Drop a few packet No CTS received • Set the RI flag in all the subsequent RTS packet • Requests the receiver to enter the RI mode Set the RI flag in all the data packet Sender earl

  10. HCAS-Receiver Receiver earl

  11. HCAS-Frame structure MAC frame format MAC Header 2 2 6 6 6 2 6 0-2312 4 位元組 Sequence Control Frame Control Duration/ID 資料 Addr 3 Addr 4 FCS Addr 1 Addr 2 Frame Control Protocol Version To DS From DS More Flag Power Mang. More Data Retry WEP Rsvd Type Subtype 2 2 4 1 1 1 1 1 1 1 1 位元 RTS Frame Frame Control Duration RA TA FCS MAC Header earl

  12. Simulation earl

  13. Simulation earl

  14. Simulation • Use GloMoSim 2.0 as the network simulator • The channel bit rate is 2Mbps • Direct sequence spread spectrum (DSSS) parameters earl

  15. Simulation(UDP) earl

  16. Simulation(UDP) earl

  17. Simulation(TCP) earl

  18. Simulation(TCP) earl

  19. Conclusion • A new hybrid channel-access schemesender-initiated and receiver-initiated • Better fairness may be achieved with almost no degradation in throughput earl

  20. References • scheme 1 achieve max-min fairness • [6] T. Ozugur, M. Naghshineh, P. Kermani, C. M. Olsen, B. Rezvani, and J. A. Copeland, “Balanced Media Access Methods for Wireless Networks,” in Proc. of ACM/IEEE MOBICOM ’98, pp. 21–32, Oct. 1998. • [10] B. Bensaou, Y. Wang, and C. C. Ko, “Fair Medium Access in 802.11 Based Wireless Ad-Hoc Networks,” in IEEE/ACM MobiHoc Workshop, Aug. 2000. • [11] X. Huang and B. Bensaou, “On Max-min Fairness and Scheduling in Wireless Ad-Hoc Networks: Analytical Framework and Implementation,” in ACM MobiHoc ’01, 2001 • Scheme 2 fair queueing • [7] T. Nandagopal, T. Kim, X. Gao, and V. Bharghavan, “Achieving MAC Layer Fairness in Wireless Packet Networks,” in ACM Mobicom 2000, (Boston, MA, U.S.), Aug. 2000. • [8] N. H. Vaidya, P. Bahl, and S. Gupta, “Distributed Fair Scheduling in a Wireless LAN,” in ACM Mobicom 2000, (Boston, MA, U.S.), Aug. 2000. • [9] H. Luo, S. Lu, and V. Bharghavan, “A New Model for Packet Scheduling in Multihop Wireless Networks,” in ACM Mobicom 2000, (Boston, MA, U.S.), Aug. 2000. • [12] H. Luo and S. Lu, “A Topology-Independent Fair Queueing Model in Ad Hoc Wireless Networks,” in IEEE ICNP 2000, (Osaka, Japan), Nov. 2000. • [13] H. Luo, P. Medvedev, J. Cheng, and S. Lu, “A Self-Coordinating Approach to Distributed Fair Queueing in Ad Hoc Wireless Networks,” in IEEE INFOCOM 2001, Apr. 2001 earl

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