On-Line AP Association Algorithms for 802.11n WLANs with Heterogeneous Clients

As the latest amendment of IEEE 802.11 standard, 802.11n allows a maximum raw data rate as high as 600 Mbps, making it a desirable candidate for wireless local area network (WLAN) deployment. In typical deployment, the coverage areas of nearby access points (APs) usually overlap with each other to provide satisfactory coverage and seamless mobility support. Clients tend to associate (connect) to the AP with the strongest signal strength, which may lead to poor client throughput and overloaded APs. Although a number of AP association schemes have been proposed for IEEE 802.11 WLANs in the literature, the challenges brought by the new features in 802.11n have not been thoroughly studied nor the impact of legacy 802.11a/b/g clients in 802.11n WLANS on AP association. To fill in this gap, in this paper, we explore AP association for 802.11n with heterogeneous clients (802.11a/b/g/n). We first present a bi-dimensional Markov model to estimate the uplink and downlink throughput of clients and formulate AP association into an optimization problem, aiming at providing each client a bandwidth proportional to its usable data rate. Based on this Markov model, we propose an on-line AP association algorithm under the condition that each client can acquire timely information of all clients associated with nearby APs. Furthermore, for WLANs with densely deployed APs, we provide another on-line AP association algorithm with lower complexity, which takes full advantage of 802.11n transmissions by simply associating different types of clients with different APs. We have conducted extensive simulations and experiments to validate the proposed algorithms. The results show that our algorithms can significantly improve both 802.11n throughput and aggregated network throughput under various network scenarios, compared to previous AP association schemes. Our experiments also confirm the effectiveness of the algorithms in enhancing network throughput, maintaining proportional fairness among clients, and balancing load among APs.

[1]  Wenchao Xu,et al.  A Game Theoretical Approach for Load Balancing User Association in 802.11 Wireless Networks , 2010, 2010 IEEE Global Telecommunications Conference GLOBECOM 2010.

[2]  JongWon Kim,et al.  Distributed Fair Access Point Selection for Multi-Rate IEEE 802.11 WLANs , 2008, CCNC.

[3]  Yang Richard Yang,et al.  Proportional Fairness in Multi-Rate Wireless LANs , 2008, IEEE INFOCOM 2008 - The 27th Conference on Computer Communications.

[4]  Seongkwan Kim,et al.  CARA: Collision-Aware Rate Adaptation for IEEE 802.11 WLANs , 2006, Proceedings IEEE INFOCOM 2006. 25TH IEEE International Conference on Computer Communications.

[5]  Rui Li,et al.  Cross layer association control for throughput optimization in wireless LANs with inter-AP interference , 2010, MSWIM '10.

[6]  Joy Kuri,et al.  An Estimated Delay Based Association Policy for Web Browsing in a Multirate WLAN , 2012, IEEE Transactions on Network and Service Management.

[7]  Fred Daneshgaran,et al.  On the throughput performance of multirate IEEE 802.11 networks with variable-loaded stations: analysis, modeling, and a novel proportional fairness criterion , 2010 .

[8]  David Schwab,et al.  Characterising the use of a campus wireless network , 2004, IEEE INFOCOM 2004.

[9]  Yuanyuan Yang,et al.  Enhancing Downlink Performance in Wireless Networks by Simultaneous Multiple Packet Transmission , 2006, IEEE Transactions on Computers.

[10]  Dipankar Raychaudhuri,et al.  SplitAP: Leveraging Wireless Network Virtualization for Flexible Sharing of WLANs , 2010, 2010 IEEE Global Telecommunications Conference GLOBECOM 2010.

[11]  J. Kuri,et al.  Online Client-AP Association in WLANs , 2006, 2006 4th International Symposium on Modeling and Optimization in Mobile, Ad Hoc and Wireless Networks.

[12]  Wenchao Xu,et al.  Channel Assignment and User Association Game in Dense 802.11 Wireless Networks , 2011, 2011 IEEE International Conference on Communications (ICC).

[13]  Magdalena Balazinska,et al.  Characterizing mobility and network usage in a corporate wireless local-area network , 2003, MobiSys '03.

[14]  Thomas Bonald,et al.  The impact of association on the capacity of WLANs , 2009, 2009 7th International Symposium on Modeling and Optimization in Mobile, Ad Hoc, and Wireless Networks.

[15]  Özgür Erçetin,et al.  Association games in IEEE 802.11 wireless local area networks , 2008, IEEE Transactions on Wireless Communications.

[16]  N. Papaoulakis,et al.  A Proactive, Terminal Based Best Access Point Selection Mechanism for Wireless LANs , 2008, 2008 IEEE Globecom Workshops.

[17]  Konstantina Papagiannaki,et al.  Measurement-Based Self Organization of Interfering 802.11 Wireless Access Networks , 2007, IEEE INFOCOM 2007 - 26th IEEE International Conference on Computer Communications.

[18]  Ren Ping Liu,et al.  WLAN Location Service with TXOP , 2013, IEEE Transactions on Computers.

[19]  Yuanyuan Yang,et al.  A novel contention-based MAC protocol with channel reservation for wireless LANs , 2005, 2nd International Conference on Broadband Networks, 2005..

[20]  Parameswaran Ramanathan,et al.  Joint association and power adaption in WiFi community networks , 2011, 2011 45th Annual Conference on Information Sciences and Systems.

[21]  Leandros Tassiulas,et al.  Contention and traffic load-aware association in IEEE 802.11 WLANs: Algorithms and implementation , 2011, 2011 International Symposium of Modeling and Optimization of Mobile, Ad Hoc, and Wireless Networks.

[22]  Chun-Ting Chou,et al.  Contention-Based Airtime Usage Control in Multirate IEEE 802.11 Wireless LANs , 2006, IEEE/ACM Transactions on Networking.

[23]  Suman Banerjee,et al.  802.11n under the microscope , 2008, IMC '08.

[24]  Paramvir Bahl,et al.  Cell Breathing in Wireless LANs: Algorithms and Evaluation , 2007, IEEE Transactions on Mobile Computing.

[25]  Seung-Jae Han,et al.  Fairness and Load Balancing in Wireless LANs Using Association Control , 2004, IEEE/ACM Transactions on Networking.

[26]  Soung Chang Liew,et al.  Proportional Fairness in Multi-Channel Multi-Rate Wireless Networks-Part I: The Case of Deterministic Channels with Application to AP Association Problem in Large-Scale WLAN , 2008, IEEE Transactions on Wireless Communications.

[27]  Lan Chen,et al.  Access Point Selection Strategy for Large-Scale Wireless Local Area Networks , 2007, 2007 IEEE Wireless Communications and Networking Conference.

[28]  Martin Heusse,et al.  Performance anomaly of 802.11b , 2003, IEEE INFOCOM 2003. Twenty-second Annual Joint Conference of the IEEE Computer and Communications Societies (IEEE Cat. No.03CH37428).

[29]  Wen-Tsuen Chen,et al.  An Efficient Multipolling Mechanism for IEEE 802.11 Wireless LANs , 2003, IEEE Trans. Computers.

[30]  S. Srikanth,et al.  Performance study of IEEE 802.11n WLANs , 2009, 2009 First International Communication Systems and Networks and Workshops.

[31]  Hyeonmok Ko,et al.  A joint approach to bandwidth allocation and AP-client association for WLANs , 2010, IEEE Local Computer Network Conference.

[32]  Srikanth V. Krishnamurthy,et al.  ACORN: An Auto-Configuration Framework for 802.11n WLANs , 2013, IEEE/ACM Transactions on Networking.

[33]  Younghwan Yoo,et al.  Airtime Fairness for IEEE 802.11 Multirate Networks , 2008, IEEE Transactions on Mobile Computing.