Improving Throughput and Fairness by Reducing Exposed and Hidden Nodes in 802.11 Networks

Two well-known problems that can cause performance degradations in IEEE 802.11 wireless networks are the exposed-node (EN) and hidden-node (HN) problems. Although there have been isolated and incidental studies of EN and HN, a comprehensive treatment has not been attempted. The contributions of this paper are threefold: First, we provide rigorous mathematical definitions for EN and HN in wireless networks (including wireless local area networks (WLANs) with multiple access points (APs) and ad hoc networks). Second, we relate EN to the nonscalability of network throughput and HN to unfair throughput distributions. Third, we provide schemes to eliminate EN and HN, respectively. We show that the standard 802.11 technology is not scalable because, due to EN, more APs do not yield higher total throughput. By removing EN, our schemes make it possible to achieve scalable throughput commensurate with the seminal theoretical results in [1] and [2]. In addition, by removing HN, our schemes solve the performance problems triggered by HN, including throughput unfairness/starvation and rerouting instability.

[1]  Mario Gerla,et al.  How effective is the IEEE 802.11 RTS/CTS handshake in ad hoc networks , 2002, Global Telecommunications Conference, 2002. GLOBECOM '02. IEEE.

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

[3]  Panganamala Ramana Kumar,et al.  RHEINISCH-WESTFÄLISCHE TECHNISCHE HOCHSCHULE AACHEN , 2001 .

[4]  Marwan Krunz,et al.  Power controlled dual channel (PCDC) medium access protocol for wireless ad hoc networks , 2003, IEEE INFOCOM 2003. Twenty-second Annual Joint Conference of the IEEE Computer and Communications Societies (IEEE Cat. No.03CH37428).

[5]  Mario Gerla,et al.  Effectiveness of RTS/CTS handshake in IEEE 802.11 based ad hoc networks , 2003, Ad Hoc Networks.

[6]  Soung Chang Liew,et al.  Offered load control in IEEE 802.11 multi-hop ad-hoc networks , 2004, 2004 IEEE International Conference on Mobile Ad-hoc and Sensor Systems (IEEE Cat. No.04EX975).

[7]  Shugong Xu,et al.  Does the IEEE 802.11 MAC protocol work well in multihop wireless ad hoc networks? , 2001, IEEE Commun. Mag..

[8]  Theodore S. Rappaport,et al.  Wireless communications - principles and practice , 1996 .

[9]  Giorgio Ventre,et al.  Network Simulator NS2 , 2008 .

[10]  Soung Chang Liew,et al.  Achieving scalable performance in large-scale IEEE 802.11 wireless networks , 2005, IEEE Wireless Communications and Networking Conference, 2005.

[11]  Soung Chang Liew,et al.  Removing hidden nodes in IEEE 802.11 wireless networks , 2005, VTC-2005-Fall. 2005 IEEE 62nd Vehicular Technology Conference, 2005..

[12]  Brahim Bensaou,et al.  On max-min fairness and scheduling in wireless ad-hoc networks: analytical framework and implementation , 2001, MobiHoc '01.

[13]  Soung Chang Liew,et al.  Re-routing instability in IEEE 802.11 multi-hop ad-hoc networks , 2004, 29th Annual IEEE International Conference on Local Computer Networks.

[14]  Rajeev Shorey,et al.  Performance of TCP and UDP protocols in multi-hop multi-rate wireless networks , 2004, 2004 IEEE Wireless Communications and Networking Conference (IEEE Cat. No.04TH8733).

[15]  Panganamala Ramana Kumar,et al.  Capacity bounds for ad hoc and hybrid wireless networks , 2004, CCRV.

[16]  Vaduvur Bharghavan,et al.  MACAW: a media access protocol for wireless LAN's , 1994, SIGCOMM 1994.

[17]  Jing Deng,et al.  Dual busy tone multiple access (DBTMA)-a multiple access control scheme for ad hoc networks , 2002, IEEE Trans. Commun..

[18]  K. Kanth,et al.  Performance enhancement of TCP on multihop ad hoc wireless networks , 2002, 2002 IEEE International Conference on Personal Wireless Communications.

[19]  Charles E. Perkins,et al.  Ad-hoc on-demand distance vector routing , 1999, Proceedings WMCSA'99. Second IEEE Workshop on Mobile Computing Systems and Applications.

[20]  Vaduvur Bharghavan,et al.  A power controlled multiple access protocol for wireless packet networks , 2001, Proceedings IEEE INFOCOM 2001. Conference on Computer Communications. Twentieth Annual Joint Conference of the IEEE Computer and Communications Society (Cat. No.01CH37213).