Poster: Motivating an Inter-networking Architecture forWSN/IoT

Laura Marie FeeneySwedish Institute of Computer Science

http://www.sics.se/∼lmfeeney

1. INTER-NETWORK INTERFERENCEGrowing commercial development of WSN/WBAN/IoT

solutions will eventually lead to their ubiquitous deploy-ment. Inevitably, there will be environments that containmany independent, co-located networks with overlapping ar-eas of wireless coverage. Examples of high density scenariosinclude transit stations and urban housing.Because these various networks and applications will be

owned by different people and because they mostly oper-ate in ISM bands, there is no trusted authority that cancoordinate their activity. Cross-technology interference hasbeen widely studied, e.g. between IEEE 802.11 and IEEE802.15.4, but very little work has addressed inter-network in-terference between co-located WSNs using the same commu-nication technology. However, the potentially large numberof co-located networks and fairly small number of channelssuggests that this will not be an unusual situation.The risk of external frames being received and misinter-

preted as local frames is studied in [2], which emphasized theneed for authentication on all frames. Interference betweenco-located IEEE 802.15.4 PANs is demonstrated in [3]. Thiswork reflects a similar interest in timing and interference in-teractions between networks that can receive and identify,but not decrypt, each other’s frames.The diversity of IEEE 802.15.4-based WSN protocols is

the motivating use case. These protocols use the same PHY/MAC in very different ways, from pure unslotted CSMAto the scheduled mesh in WirelessHART. Such significantdifferences in channel access mechanisms can lead to adverseinteractions between independent networks, which will notbe able to explicitly negotiate (or even infer) how to sharethe channel efficiently.Thus the long-term goal of this work-in-progress is to mo-

tivate the development of architecture and design principlesthat can mitigate problems of inter-network interference.As a specific example, consider two kinds of asynchronous

MAC layers. Figure 1 shows interactions between networksusing an X-MAC [1] type protocol (i.e. sender strobes, re-ceivers periodically listen) and an RI-MAC [4] type protocol

Permission to make digital or hard copies of part or all of this work for personal orclassroom use is granted without fee provided that copies are not made or distributedfor profit or commercial advantage, and that copies bear this notice and the full ci-tation on the first page. Copyrights for third-party components of this work must behonored. For all other uses, contact the owner/author(s). Copyright is held by theauthor/owner(s).MobiSys’14, June 16–19, 2014, Bretton Woods, New Hampshire, USA.ACM 978-1-4503-2793-0/14/06.http://dx.doi.org/10.1145/2594368.2601449.

RI−MAC

listen

listen

ACK

strobe

announce

announce

announce announce

announce

announce

listen listen

sender

sender

X−MAC

Figure 1: Interaction between X-MAC and RI-MAC(there are many variations of both protocols, the ba-sic structure is shown). Dotted lines show conflicts.

(i.e. sender listens, receivers periodically strobe). The fig-ure shows two specific collision scenarios in this case. If thenetworks have the same period, the listen intervals of X-MAC nodes and the RI-MAC node announcements shouldbe de-synchronized, as should correlated data transmissions.Mechanisms providing this functionality would increase re-silience in the presence of co-located networks.

2. REFERENCES[1] M. Buettner, G. V. Yee, E. Anderson, and R. Han.

X-MAC: a short preamble mac protocol for duty-cycledwireless sensor networks. In 4th ACM Conf onEmbedded Networked Sensor Systems (SenSys), 2006.

[2] L. M. Feeney. Exploring semantic interference inheterogenous sensor networks. In 1st ACM Workshopon Heterogeneous Sensor and Actor Networks, 2008.

[3] N. Nordin and F. Dressler. Effects and implications ofbeacon collisions in co-located IEEE 802.15. 4 networks.In IEEE Vehicular Technology Conf (VTC Fall), 2012.

[4] Y. Sun, O. Gurewitz, and D. B. Johnson. RI-MAC: Areceiver-initiated asynchronous duty cycle MACprotocol for dynamic traffic loads in wireless sensornetworks. In 6th ACM Conf on Embedded NetworkSensor Systems (SenSys), 2008.

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