QQDCA: Adapting IEEE 802.11 EDCA for unicast transmissions at high topology dynamics

We present Multi-Queue Distributed Channel Access (QQDCA), an improved MAC scheme to mitigate the head-of-line (HOL) blocking problem observed in highly dynamic networks when Wireless LAN (WLAN) unicast (re-)transmissions are used. Focusing on Vehicular Ad Hoc Networks (VANETs) as a prime example, our novel MAC protocol can be used for all IEEE 802.11 based wireless networks having very dynamic topologies. In brief, failing unicast messages create a problem by blocking all remaining frames in the transmit queue until they are successfully acknowledged or the maximum retransmission counter expires. This HOL blocking has been identified as a rare or temporary phenomenon in the late 1990s already. However, it turned out that the problem is both much more frequent and persistent in VANETs due to their very dynamic nature. Here, it may take a substantial amount of time in which no other message can be sent. We present and discuss QQDCA to address this problem, analytically show its benefits, and evaluate the protocol in an extensive simulation study. QQDCA can reduce the delay induced by HOL blocking by up to 95 %.

[1]  Vinay Kolar,et al.  Avoiding head of line blocking in directional antenna [MAC protocol] , 2004, 29th Annual IEEE International Conference on Local Computer Networks.

[2]  Thomas Engel,et al.  Luxembourg SUMO Traffic (LuST) Scenario: 24 hours of mobility for vehicular networking research , 2015, 2015 IEEE Vehicular Networking Conference (VNC).

[3]  A. M. Abdullah,et al.  Wireless lan medium access control (mac) and physical layer (phy) specifications , 1997 .

[4]  Reinhard German,et al.  Bidirectionally Coupled Network and Road Traffic Simulation for Improved IVC Analysis , 2011, IEEE Transactions on Mobile Computing.

[5]  Christina Fragouli,et al.  Controlled multimedia wireless link sharing via enhanced class-based queuing with channel-state-dependent packet scheduling , 1998, Proceedings. IEEE INFOCOM '98, the Conference on Computer Communications. Seventeenth Annual Joint Conference of the IEEE Computer and Communications Societies. Gateway to the 21st Century (Cat. No.98.

[6]  Sathya Narayanan,et al.  CoopMAC: A Cooperative MAC for Wireless LANs , 2007, IEEE Journal on Selected Areas in Communications.

[7]  Soung Chang Liew,et al.  An adaptive round robin scheduler for head-of-line-blocking problem in wireless LANs , 2005, IEEE Wireless Communications and Networking Conference, 2005.

[8]  Ozan K. Tonguz,et al.  Broadcast storm mitigation techniques in vehicular ad hoc networks , 2007, IEEE Wireless Communications.

[9]  Falko Dressler,et al.  IEEE 802.11p unicast considered harmful , 2015, 2015 IEEE Vehicular Networking Conference (VNC).

[10]  Hongqiang Zhai,et al.  Opportunistic packet Scheduling and Media Access control for wireless LANs and multi-hop ad hoc networks , 2004, 2004 IEEE Wireless Communications and Networking Conference (IEEE Cat. No.04TH8733).

[11]  Reuven Cohen,et al.  Not All VANET Broadcasts Are the Same: Context-Aware Class Based Broadcast , 2018, IEEE/ACM Transactions on Networking.

[12]  Nj Piscataway,et al.  Wireless LAN medium access control (MAC) and physical layer (PHY) specifications , 1996 .

[13]  John M. Cioffi,et al.  Opportunistic CSMA/CA for achieving multi-user diversity in wireless LAN , 2009, IEEE Transactions on Wireless Communications.

[14]  Lili Qiu,et al.  ER: efficient retransmission scheme for wireless LANs , 2007, CoNEXT '07.

[15]  Satish K. Tripathi,et al.  Enhancing throughput over wireless LANs using channel state dependent packet scheduling , 1996, Proceedings of IEEE INFOCOM '96. Conference on Computer Communications.

[16]  Hongqiang Zhai,et al.  Opportunistic media access control and rate adaptation for wireless ad hoc networks , 2004, 2004 IEEE International Conference on Communications (IEEE Cat. No.04CH37577).

[17]  Reinhard German,et al.  A computationally inexpensive empirical model of IEEE 802.11p radio shadowing in urban environments , 2011, 2011 Eighth International Conference on Wireless On-Demand Network Systems and Services.