Models of 802.11 multi-hop networks: Theoretical insights and experimental validation

Wireless Multi-Hop CSMA/CA Networks are challenging to analyze. On the one hand, their dynamics are complex and rather subtle effects may severely affect their performance. Yet, understanding these effects is critical to operate upper layer protocols, such as TCP/IP. On the other hand, their models tend to be very complex in order to reproduce all the features of the protocol. As a result, they do not convey much insight into the essential features. We review two models of 802.11 protocols, which are simple enough to first explain why a trade-off needs to be found between fairness and spatial reuse (throughput) in saturated wireless networks (where all nodes have packets to transmit to their neighbors); and then to explain why non-saturated networks (where only some nodes, the sources, have packets to transmit to their destinations in a multi-hop fashion) that are more than 3 hops longs suffer from instability.We confront both models either to realistic simulations in ns-2 or to experiments with a testbed deployed at EPFL. We find that the predictions of both models help us understand the performance of the 802.11 protocol, and provide hints about the changes that need to be brought to the protocol.

[1]  Asuman E. Ozdaglar,et al.  Achievable rate region of CSMA schedulers in wireless networks with primary interference constraints , 2007, 2007 46th IEEE Conference on Decision and Control.

[2]  Konstantinos Psounis,et al.  The Achievable Rate Region of 802.11-Scheduled Multihop Networks , 2009, IEEE/ACM Transactions on Networking.

[3]  David Starobinski,et al.  Elucidating the Instability of Random Access Wireless Mesh Networks , 2009, 2009 6th Annual IEEE Communications Society Conference on Sensor, Mesh and Ad Hoc Communications and Networks.

[4]  Yuliy Baryshnikov,et al.  Space filling and depletion , 2004, Journal of Applied Probability.

[5]  David Starobinski,et al.  EZ-Flow: removing turbulence in IEEE 802.11 wireless mesh networks without message passing , 2009, CoNEXT '09.

[6]  Sem C. Borst,et al.  Insensitivity and stability of random-access networks , 2010, Perform. Evaluation.

[7]  Michele Garetto,et al.  Modeling Per-Flow Throughput and Capturing Starvation in CSMA Multi-Hop Wireless Networks , 2006, Proceedings IEEE INFOCOM 2006. 25TH IEEE International Conference on Computer Communications.

[8]  Ramesh Govindan,et al.  Online optimization of 802.11 mesh networks , 2009, CoNEXT '09.

[9]  Alexandre Proutière,et al.  Throughput of random access without message passing , 2008, 2008 42nd Annual Conference on Information Sciences and Systems.

[10]  Patrick Thiran,et al.  Understanding the Gap between the IEEE 802.11 Protocol Performance and the Theoretical Limits , 2006, 2006 3rd Annual IEEE Communications Society on Sensor and Ad Hoc Communications and Networks.

[11]  Olivier Dousse.  Revising buffering in multihop CSMA/CA wireless networks , 2007, 2007 4th Annual IEEE Communications Society Conference on Sensor, Mesh and Ad Hoc Communications and Networks.

[12]  Patrick Thiran,et al.  On the fairness of large CSMA networks , 2009, IEEE Journal on Selected Areas in Communications.

[13]  Vincenzo Mancuso,et al.  Measurement and Modeling of the Origins of Starvation in Congestion Controlled Mesh Networks , 2008, IEEE INFOCOM 2008 - The 27th Conference on Computer Communications.

[14]  Michele Garetto,et al.  Modeling media access in embedded two-flow topologies of multi-hop wireless networks , 2005, MobiCom '05.

[15]  Patrick Thiran,et al.  A Packing Approach to Compare Slotted and Non-Slotted Medium Access Control , 2006, Proceedings IEEE INFOCOM 2006. 25TH IEEE International Conference on Computer Communications.

[16]  A. Warrier,et al.  DiffQ: Practical Differential Backlog Congestion Control for Wireless Networks , 2009, IEEE INFOCOM 2009.

[17]  F.A. Tobagi,et al.  Modeling and performance analysis of multihop packet radio networks , 1987, Proceedings of the IEEE.

[18]  Basil S. Maglaris,et al.  Throughput Analysis in Multihop CSMA Packet Radio Networks , 1987, IEEE Trans. Commun..

[19]  Devavrat Shah,et al.  Network adiabatic theorem: an efficient randomized protocol for contention resolution , 2009, SIGMETRICS '09.

[20]  Ray Jain,et al.  The art of computer systems performance analysis - techniques for experimental design, measurement, simulation, and modeling , 1991, Wiley professional computing.

[21]  Johan van Leeuwaarden,et al.  Spatial fairness in linear random-access networks , 2012, Perform. Evaluation.

[22]  Isabelle Guérin Lassous,et al.  Experiments of Some Performance Issues with IEEE 802.11b in Ad Hoc Networks , 2005, Second Annual Conference on Wireless On-demand Network Systems and Services.

[23]  Koushik Kar,et al.  Throughput modelling and fairness issues in CSMA/CA based ad-hoc networks , 2005, Proceedings IEEE 24th Annual Joint Conference of the IEEE Computer and Communications Societies..

[24]  Konstantinos Psounis,et al.  The achievable rate region of 802.11-scheduled multihop networks , 2009, TNET.

[25]  Jean C. Walrand,et al.  A Distributed CSMA Algorithm for Throughput and Utility Maximization in Wireless Networks , 2010, IEEE/ACM Transactions on Networking.

[26]  S. Zachary,et al.  Loss networks , 2009, 0903.0640.

[27]  Fabrice Guillemin,et al.  Wireless multi-hop networks with stealing: Large buffer asymptotics , 2010, 2010 22nd International Teletraffic Congress (lTC 22).

[28]  Patrick Thiran,et al.  Self-Organization Properties of CSMA/CA Systems and Their Consequences on Fairness , 2009, IEEE Transactions on Information Theory.