MAC. MAC Protocol for Hidden Terminal Problem Alleviation using Transmission Pause Control in Wireless Multi Hop Networks

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1 THE INSTITUTE OF ELECTRONICS, INFORMATION AND COMMUNICATION ENGINEERS TECHNICAL REPORT OF IEICE. MAC IEEE82.11 DCF(Distributed Coordination Function) MAC MAC IEEE82.11 DCF Abstract MAC Protocol for Hidden Terminal Problem Alleviation using Transmission Control in Wireless Multi Hop Networks Shota FURUKAWA, Hiroo SEKIYA, Nobuyoshi KOMURO, and Shiro SAKATA Graduate School of Advanced Integration Science, Chiba University 1-33, Yayoi-cho, Inage-ku, Chiba, Japan When IEEE82.11 DCF (Distributed Coordination Function) is applied to wireless multi hop network, network throughput decreases and energy consumption increases due to the increase of packet collisions caused by hidden terminals. This paper proposes the MAC (Medium Access Control) protocol for hidden terminal problem alleviation using transmission pause control in wireless multi hop networks. In the proposed protocol, terminals pause packet transmissions until the buffer usage ratio is larger than the threshold. As a result, the number of contention terminal decreases because of transmission pause. Thus, the proposed protocol can reduce packet collision. Simulation results show that the proposed protcol can reduce packet collision between transmitting terminal and hidden terminal. It is also shown that the throughput of proposed protocol is better than that of IEEE82.11 DCF and. Key words Wireless Multi-Hop Networks, MAC, IEEE82.11 DCF, Hidden Terminal Problem, Transmission Control, Buffer Usage Ratio 1. LAN(Local Area network) MAC IEEE82.11 DCF(Distributed Coordination Function) [1] DCF IEEE82.11 DCF MAC(Medium Access Control) [2] - [4] RTS/CTS(Request to Send / Clear to Send) RTS/CTS RTS RTS CTS 1

2 RTS/CTS RTS RTS/CTS DCF QoS (Quality of Service) QoS IEEE82.11e EDCA (Enhanced Distributed Channel Access) [5] EDCA AC(Access Category) EDCA [6] EDCA/CA (EDCA / Contention Adaption) EDCA/CA TXOP(Transmission Opportunity) LAN TXOP EDCA/CA LAN EDCA/CA EDCA/CA MAC IEEE82.11 DCF [1] IEEE82.11 DCF LAN MAC DCF CSMA/CA(Carrier Sense Multiple Access with Collision Avoidance) DIFS(Distributed Inter Flame Space) DIFS BT(Backoff Timer) BT CW (Contention Window) Slot Time BT CW 2 BT BT DCF [3] RTS/CTS RTS RTS SIFS(Short Inter Flame Space) CTS RTS CTS CTS SIFS RTS/CTS RTS RTS/CTS 2. 2 EDCA/CA [6] LAN IEEE82.11e EDCA VO(Voice) VI(Video) [6] [7] [6] EDCA/CA EDCA/CA TXOP VO VI EDCA/CA LAN RTS/CTS EDCA/CA 3. MAC q length θ θ 2

3 θ θ Throughput (kbyte/s) θ = 1 θ = 2 θ = 3 θ = 35 θ = 4 θ Node1 Node2 Node3 3 θ Physical layer IEEE82.11a MAC protocol IEEE82.11 DCF Transport layer UDP Channel bit rate 54 Mbps transmission range 5 m CW min 15 CW max 123 Retransmission limit 7 PacketSize 128 bytes Packet Interval 2 ms Flow Rate 64 kbyte/s Collision Probability θ = 1 θ = 2 θ = 3 θ = 35 θ = q length = () (1) 5 4 θ q length > = θ ( ) (2) (1) 1 θ 1 θ Average delay (ms) θ = 1 4 θ = 2 θ = 3 3 θ = 35 2 θ = θ DCF RTS/CTS DCF (DCF with RTS/CTS) (Proposed)

4 7 4 Throughput (kbyte/s) Average delay (ms) DCF RTS/CTS DCF 8 DCF RTS/CTS DCF Collision Probability Energy Consumption ( joule) DCF RTS/CTS DCF 9 DCF RTS/CTS DCF s 1.65 W 1.4 W 1.15 W [7] 1 3 s 4. 2 θ θ θ 3 θ 4 θ 3 4 θ θ θ > 35 θ 5 θ 5 6 θ, θ 4 7 θ 4 ms( [8] 1) θ = DCF RTS/CTS DCF 7 6 DCF 7 RTS/CTS DCF 7 DCF RTS/CTS DCF RTS/CTS DCF 7 DCF 8 DCF RTS/CTS DCF 8 6 RTS/CTS 4

5 (a) (b) (a) (b) Time (s) (a) DCF 6 (b) Time (s) 11 1 (a) DCF 1 (b) 1 DCF 7 DCF DCF RTS/CTS DCF 9 RTS/CTS DCF DCF RTS/CTS DCF RTS/CTS DCF 8 RTS/CTS DCF (a) DCF

6 2 4 7 DCF 1 (b) 6 θ 11 (a) DCF 1 11 (b) 1 θ DCF DCF 5. QoS MAC [1] IEEE Computer Society LAN MAN Standards Committee., Wireless LAN medium access control (MAC) and physical layer (PHY) specifications, IEEE Std [2] A. Yamada, A. Fujiwara, Y. Matsumoto, Experimental evaluation of adaptive contention window control for layer-2 mesh networks,, RCS25-59, July 25. [3] M. Inaba, Y. Tsuchiya, H. Sekiya, S. Sakata, and K. Yagyu Analysis and Experiments of Maximum Throughput in Wireless Multihop Networks for VoIP Applications IEICE Trans. E92-B no.1 29 [4] L. Hanzo, and R. Tafazolli, A survey of QoS rouing solutions for mobile ad hoc networks, IEEE Commun. Surveys and Tutorials, vol. 9, no. 2, pp. 5-7, Second Quarter 27. [5] IEEE Standard 82.11: Wireless LAN medium access control (MAC) and physical layer (PHY) specifications: Medium access control (MAC) Quality of Service (QoS) Enhancements, IEEE 82.11e Std, 25. [6] J. C. Chen and K. W. Cheng, EDCA/CA: Enhancement of IEEE 82.11e EDCA by Contention Adaption for Energy Efficiency, IEEE Trans. Wireless Communications,VOL. 7, NO. 8, pp , August 28. [7] Y. W. Lan, J. H. Yeh, J. C. Chen, and Z. T. Chou, Performance enhancement of IEEE 82.11e EDCA by contention adaption, in Proc. IEEE VTC, pp , May 25. [8] ITU-T Recommendation Y : Network Performance Objectives for IP-Based Services, Feb. 22. MAC θ θ > 35 θ θ = DCF 1 1 DCF DCF 7 8 DCF