On link asymmetry and one-way estimation in wireless sensor networks

Link asymmetry is one of the unique challenges that wireless sensor networks pose in the design of network protocols. We observe, based on testbed experiments, that a substantial percentage of links are asymmetric, many are even unidirectional. We also find that the reliability of synchronous acknowledgments is considerably higher than that of asynchronous messages. Thus the norm of estimating link quality bidirectionally via asynchronous beacons underestimates the link reliability of asymmetric links. This leads us to investigate how to exploit asymmetric links in order to improve network functions such as convergecast routing in sensor networks via one-way link estimation. We propose a new one-way link metric ETF (for the expected number of transmissions over forward links) and present a local procedure for its estimation. We use ETF to identify reliable forward links, and we use dynamic retransmission thresholding for error control. Via experiments on testbeds of CC1000 radios and CC2420 radios (an IEEE 802.15.4-compliant radio), we quantify the performance improvement in ETF as compared with ETX. We also study the performance improvement of ETF over ETX when no special mechanism is employed to discover asymmetric links or to control retransmissions.

[1]  Ramesh Govindan,et al.  Interaction of retransmission, blacklisting, and routing metrics for reliability in sensor network routing , 2004, 2004 First Annual IEEE Communications Society Conference on Sensor and Ad Hoc Communications and Networks, 2004. IEEE SECON 2004..

[2]  Gang Zhou,et al.  Models and solutions for radio irregularity in wireless sensor networks , 2006, TOSN.

[3]  Robert Tappan Morris,et al.  Link-level measurements from an 802.11b mesh network , 2004, SIGCOMM '04.

[4]  Robert Tappan Morris,et al.  a high-throughput path metric for multi-hop wireless routing , 2003, MobiCom '03.

[5]  David E. Culler,et al.  Taming the underlying challenges of reliable multihop routing in sensor networks , 2003, SenSys '03.

[6]  Vinayak S. Naik,et al.  A line in the sand: a wireless sensor network for target detection, classification, and tracking , 2004, Comput. Networks.

[7]  Philip Levis,et al.  The β-factor: measuring wireless link burstiness , 2008, SenSys '08.

[8]  Calvin Newport,et al.  The mistaken axioms of wireless-network research , 2003 .

[9]  Daniel Mossé,et al.  Providing a bidirectional abstraction for unidirectional ad hoc networks , 2002, Proceedings.Twenty-First Annual Joint Conference of the IEEE Computer and Communications Societies.

[10]  John S. Heidemann,et al.  RBP: robust broadcast propagation in wireless networks , 2006, SenSys '06.

[11]  Philip Levis,et al.  Understanding the causes of packet delivery success and failure in dense wireless sensor networks , 2006, SenSys '06.

[12]  V. Kulathumani,et al.  Kansei: a testbed for sensing at scale , 2006, 2006 5th International Conference on Information Processing in Sensor Networks.

[13]  Ramesh Govindan,et al.  Understanding packet delivery performance in dense wireless sensor networks , 2003, SenSys '03.

[14]  Deborah Estrin,et al.  Temporal Properties of Low Power Wireless Links: Modeling and Implications on Multi-Hop Routing , 2005 .

[15]  Mahesh K. Marina,et al.  Routing performance in the presence of unidirectional links in multihop wireless networks , 2002, MobiHoc '02.

[16]  Kang G. Shin,et al.  On accurate measurement of link quality in multi-hop wireless mesh networks , 2006, MobiCom '06.

[17]  Prasun Sinha,et al.  Learn on the Fly: Data-Driven Link Estimation and Routing in Sensor Network Backbones , 2006, Proceedings IEEE INFOCOM 2006. 25TH IEEE International Conference on Computer Communications.

[18]  Jitendra Padhye,et al.  Comparison of routing metrics for static multi-hop wireless networks , 2004, SIGCOMM '04.

[19]  KeshavSrinivasan.  A control-theoretic approach to flow control , 1991 .

[20]  Yehuda Afek,et al.  Distributed Algorithms for Unidirectional Networks , 1994, SIAM J. Comput..

[21]  Srinivasan Keshav.  A control-theoretic approach to flow control , 1991, SIGCOMM 1991.

[22]  Satish K. Tripathi,et al.  Signal stability-based adaptive routing (SSA) for ad hoc mobile networks , 1997, IEEE Wirel. Commun..

[23]  Marco Zuniga,et al.  An analysis of unreliability and asymmetry in low-power wireless links , 2007, TOSN.

[24]  Hongwei Zhang,et al.  On exploiting asymmetric wireless links via one-way estimation , 2007, MobiHoc '07.

[25]  AroraAnish,et al.  On link asymmetry and one-way estimation in wireless sensor networks , 2010 .