Abstract — This paper argues for the usefulness of an application-cooperative interactive management system for wireless sensor networks, and presents SNMS, a Sensor Network Management System. SNMS is designed to be simple and have minimal impact on memory and network traffic, while remaining open and flexible. The system is evaluated in light of issues derived from real deployment experiences. I.

This paper presents and evaluates two principles for wireless routing protocols. The first is datapath validation: data traffic quickly discovers and fixes routing inconsistencies. The second is adaptive beaconing: extending the Trickle algorithm to routing control traffic reduces route repair latency and sends fewer beacons. We evaluate datapath validation and adaptive beaconing in CTP Noe, a sensor network tree collection protocol. We use 12 different testbeds ranging in size from 20–310 nodes, comprising seven platforms, and six different link layers, on both interference-free and interference-prone channels. In all cases, CTP Noe delivers> 90 % of packets. Many experiments achieve 99.9%. Compared to standard beaconing, CTP Noe sends 73 % fewer beacons while reducing topology repair latency by 99.8%. Finally, when using low-power link layers, CTP Noe has duty cycles of 3 % while supporting aggregate loads of 30 packets/minute.

We propose using application specific virtual machines (ASVMs) to reprogram deployed wireless sensor networks. ASVMs provide

Wireless sensor networks have the potential to be tremendously beneficial to society. Embedded sensing will enable new scientific exploration, lead to better engineering, improve productivity, and enhance security.

In Wireless Sensor Networks, many applications like structure monitoring require collecting all data without loss from motes. End-to-end retransmission which is used in Internet for reliable transport layer, does not work well in Wireless Sensor Networks, since wireless communication, and constrained resources give new challenges. We looked at factors affecting reliability, and searched possible options. Information redundancy like retransmission, erasure code, and thick path are candidates. However, if loss is not randomly distributed, those methods does not work well. For example, when link fails, but routing table is not updated, all packets through that path will be dropped. Route fix, which tries alternative next hop after some failure, reduces correlated consecutive drops, so that information redundancy can perform well. Experiment on real testbed in Soda Hall shows that route fix with erasure code provides good reliability. And encoding and decoding of erasure code is efficient. More investigation of data (overhead, delay) will give deeper insight in comparing options. Keywords wireless sensor networks, reliable transfer, retransmission, erasure code, route fix 1.

An overall sensornet architecture would help tame the increasingly complex structure of wireless sensornet software and help foster greater interoperability between different codebases. A previous step in this direction is the Sensornet Protocol (SP), a unifying link-abstraction layer. This paper takes the natural next step by proposing a modular network-layer for sensornets that sits atop SP. This modularity eases implementation of new protocols by increasing code reuse, and enables co-existing protocols to share and reduce code and resources consumed at run-time. We demonstrate how current protocols can be decomposed into this modular structure and show that the costs, in performance and code footprint, are minimal relative to their monolithic counterparts. 1

We investigate how to efficiently and accurately simulate wireless packet delivery. Starting from recent experimental results that have quantified signal-to-noise ratio (SNR) curves, temporal variations in propagation strength, and the effects of hardware variations, we model packet delivery using SNR. We experimentally measure noise in many different environments and propose three algorithms to simulate noise from these traces. We evaluate these algorithms in comparison to existing simulation approaches used in EmStar, TOSSIM, and ns-2 using the Kantorovich-Wasserstein distance on conditional packet delivery functions. We demonstrate that using a closest-fit pattern matching (CPM) noise model can capture complex temporal dynamics which existing approaches do not, increasing packet simulation fidelity by a factor of 2 for good links and a factor of 3 for intermediate links. Furthermore, as our models are generated from real-world traces, they are not bound to specific environments and can be easily applied to new ones. 1.

We propose application specific virtual machines as a method to safely and efficiently program sensor networks.

This paper proposes a new sensornet protocol design goal: visibility. Visibility into behaviors at the network level will simplify debugging and ease the development process. We argue that increasing visibility is the responsibility of the network protocols themselves, and not solely the responsibility of existing debugging tools. We describe a quantitative visibility metric to evaluate and compare protocols, where visibility is defined as the energy cost of diagnosing the cause of a behavior in a protocol. The design and evaluation of Pull Collection Protocol, a novel multi-hop collection protocol, is an example of how to design for visibility without sacrificing throughput or node-level fairness. We also describe our optimizations for an existing protocol, Deluge, to increase its visibility and efficiency. 1

Varying interference levels make broadcasting an unreliable operation in low-power wireless networks. Many routing and resource discovery protocols depend on flooding (repeated per-node broadcasts) over the network. Unreliability at the broadcast-level can result in either incomplete flooding coverage or excessive re-flooding, making path maintenance either unreliable or expensive. We present RBP, a very simple protocol that bolsters the reliability of broadcasting in such networks. Our protocol requires only local information, and resides as a service between the MAC and network layer, taking information from both. We show that RBP improves reliability while balancing energy efficiency. RBP is based on two principles: First, we exploit network density to achieve near-perfect flooding reliability by requiring moderate (50-70%) broadcast reliability when nodes have many neighbors. Second, we identify areas of sparse connectivity where important links bridge dense clusters of nodes, and strive for guaranteed reliability over those links. We demonstrate, through both testbed experiments and controlled simulations, that this hybrid approach is advantageous to providing nearperfect reliability for flooding with good efficiency. Testbed experiments show 99.8 % reliability with 48 % less overhead than the level of flooding required to get equivalent reliability, suggesting that routing protocols will benefit from RBP.