WSN07-1: Adjacent Channel Interference in Dual-radio 802.11a Nodes and Its Impact on Multi-hop Networking

We evaluate the performance impact of adjacent channel interference (ACI) in multi-hop wireless networks based on dual-radio 802.11a nodes. Although these nodes use chipsets that satisfy the transmit-mask requirements set by the IEEE 802.11 standard, the multi-hop performance is still significantly affected by ACI. That is, a node's transmitter can interfere with its own receiver on a different channel; as a result, multi-hop throughput is severely degraded. This degradation is especially pronounced for 802.11a. We use a spectrum analyzer with a signal combiner to quantify ACI under various conditions and propose solutions to mitigate the effect of such interference on multi-hop forwarding. Field experiments with multi-hop relay have validated these findings as well as the effectiveness of our solutions.

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

[2]  Nitin H. Vaidya,et al.  Medium access control protocols using directional antennas in ad hoc networks , 2000, Proceedings IEEE INFOCOM 2000. Conference on Computer Communications. Nineteenth Annual Joint Conference of the IEEE Computer and Communications Societies (Cat. No.00CH37064).

[3]  Robert Morris,et al.  Link-level measurements from an 802.11b mesh network , 2004, SIGCOMM 2004.

[4]  H.T. Kung,et al.  Parallel Use of Multiple Channels in Multi-hop 802.11 Wireless Networks , 2006, MILCOM 2006 - 2006 IEEE Military Communications conference.

[5]  H. T. Kung,et al.  Performance Measurement of 802.11a Wireless Links from UAV to Ground Nodes with Various Antenna Orientations , 2006, Proceedings of 15th International Conference on Computer Communications and Networks.

[6]  Robert Tappan Morris,et al.  Architecture and evaluation of an unplanned 802.11b mesh network , 2005, MobiCom '05.

[7]  Peter Steenkiste,et al.  A simple mechanism for capturing and replaying wireless channels , 2005, E-WIND '05.

[8]  Randeep Bhatia,et al.  Joint Channel Assignment and Routing for Throughput Optimization in Multiradio Wireless Mesh Networks , 2006, IEEE J. Sel. Areas Commun..

[9]  J.E. Mazo,et al.  Digital communications , 1985, Proceedings of the IEEE.

[10]  J. T. Robinson,et al.  Experimenting with a multi-radio mesh networking testbed , 2005 .

[11]  J.M. Gilbert,et al.  An integrated 802.11a baseband and MAC processor , 2002, 2002 IEEE International Solid-State Circuits Conference. Digest of Technical Papers (Cat. No.02CH37315).

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

[13]  P. Kumar,et al.  Capacity of Ad Hoc Wireless Networks , 2002 .

[14]  Kai-Ten Feng.  LMA: Location- and Mobility-Aware Medium-Access Control Protocols for Vehicular Ad Hoc Networks Using Directional Antennas , 2007, IEEE Transactions on Vehicular Technology.

[15]  Lili Qiu,et al.  Impact of Interference on Multi-Hop Wireless Network Performance , 2003, MobiCom '03.

[16]  Timothy X. Brown,et al.  Ad Hoc UAV Ground Network (AUGNet) , 2004 .

[17]  Yong Pei,et al.  On the capacity improvement of ad hoc wireless networks using directional antennas , 2003, MobiHoc '03.