Position and orientation of individual nodes in ad hoc sensor networks are useful for both service and application implementation. Services that can be enabled by availability of position include routing and querying. At application level, position is required in order to label the reported data in a sensor network, whereas position and orientation enable tracking. Nodes may have local capabilities such as the possibility of measuring ranges to neighbors, angle of arrival, or global capabilities, such as GPS and digital compasses. This article surveys methods used to infer locations in a multihop fashion in networks with or without the mentioned capabilities.

Angle of arrival (AOA) has previously been used for outdoor positioning in aircraft navigation and for services like E911. For indoor positioning, the best schemes to date rely either on extensive infrastructure, or on sampling of the signal strength on a dense grid, which is subject to changes in the environment, like furniture, elevators, or people. We present an indoor positioning architecture that does not require a signal strength map, simply requiring the placement of special VOR base stations (VORBA). While our incipient realization of the AOA using 802.11 uses a base station with a revolving directional antenna, a non mechanical implementation would yield comparable performance, even with quantized angles. Performance of positioning with VOR base stations is evaluated though experimentation, simulation, and theoretical analysis.

APS algorithms use the basic idea of distance vector routing to find positions in an ad hoc network using only a fraction of landmarks, for example GPS enabled nodes. All the nodes in the network are assumed to have the possibility of measuring: range, angle of arrival (AOA), orientation, or a combination of them. We give a lower bound for positioning error in a multihop network for a range/angle free algorithm, and examine the error characteristic of four classes of multihop APS algorithms under various condition, using theoretical analysis and simulations. Analysis of range/angle free, range based, angle based, and multimodal algorithms show a complex tradeoff between the capabilities used, the density of the network, ratio of landmarks, and the quality of the position obtained.

Proceedings of: ACM MobiArch 2011, The 6th ACM International Workshop on Mobility in the Evolving Internet Architecture, June 28, 2011, Washington, D.C.Host mobility has traditionally been solved at the network layer, but even though Mobile IP has been standardised for 15 years, it hasn’t been supported by operators. IP’s double role as a location identif er and communication endpoint identif er brings a number of functional and performance problems. We argue that the best place to handle mobility is at the transport layer. While this is not a new argument, we believe that the emerging standard of Multipath TCP (MPTCP) can be used to solve many issues related to mobility. MPTCP naturally implements make-before-break, can be incrementally deployed, is backwards compatible with standard TCP, and could even ease incremental adoption of IPv6. Using simulations and indoor experiments with WiFi and 3G, we show that MPTCP gives better throughput, achieves smoother handoffs, and can be tuned to lower energy consumption.This research was supported by Trilogy (http://www.trilogy-project.org), a research project (ICT-216372) partially funded by the European Community under its Seventh Framework Programme. European Community's Seventh Framework ProgramThis work was partly funded by POSDRU/89/1.5/S/62557Publicad