Recent News
Project officially completed
2015-08-05
The project's results have been accepted by the Foundation for Polish Science and the project is now officially completed.Another TOSN paper accepted
2014-03-04
Our paper "Bringing Modern Unit Testing Techniques to Sensornets" has been accepted for publication in ACM Transactions on Sensor Networks. Read more...Student awarded
2013-12-09
Michal Gregorczyk, our former project member received a recognition at the XXX-th Polish Information Society's Contest for the Best Master's Thesis in Computer Science. The research presented in his thesis was conducted in the project.Funding finished
2013-07-01
The funding provided for the project by the Foundation for Polish Science has finished, which formally ends some period in the project. We may be seeking for new founding sources in the near future.Short promotional video available
2013-06-18
We have made a short videoclip promoting our project. Read more...Large mobile experiment
2013-06-06
Today, we counducted an experiment with a total of 81 mobile sensor nodes. The experiment involved lots of preparations, but produced a lot of data. We hope to process them soon.Large experiment scheduled
2013-06-03
On June 6th, we plan to conduct a large scale experiment involving 90 people wearing our mobile nodes and the additional 130 static nodes.20 more nodes arrived
2013-05-28
We have just received 20 more static nodes for our testbed. We plan to use the nodes in an upcoming experiment. More information soon...TOSN paper published
2012-08-29
Our paper, "A Case for Hierarchical Routing in Low-Power Wireless Embedded Networks," has been published in volume 8 issue 3 of ACM Transactions on Sensor Networks. Read more...Testbed technical report online
2012-07-28
A technical report about our 102-node testbed is available online. Read more...Master's students recruited again
2012-06-29
We have finished the 2012 recruitment process. We received 7 high-quality applications. Unfortunately, we had to limit the number of students admitted to the project. Read more...Presentation for Master's students
2012-05-25
We have scheduled a presentation advertising the project to Master's students. During the presentation students currently involved in the project will talk about their work. The presentation will take place on Thursday, May 31, 2012 at 12:15 in room 4070 of the Faculty of Mathematics, Informatics, and Mechanics of the University of Warsaw. Read more...Recruting students again
2012-05-10
The 2012 recruitment process of the Master's students who are willing to participate in the project has started. There are again two scholarships to get. Read more...WiMAN 2012 paper accepted
2012-04-28
Our paper, "Revisiting Gossip-based Ad-Hoc Routing" has been accepted for WiMAN 2012: The Sixth International Workshop on Wireless Mesh and Ad Hoc Networks. The workshop will be held at the end of July in Munich, Germany in collocation with ICCCN 2012: the 21st IEEE Int'l Conf. on Computer Communications and Networks. Read more...90 mobile nodes arrived
2012-04-23
We have just received a batch of 90 mobile sensor nodes. We are also finishing the software that will allow the mobile nodes to communicate with the 110 static ones.100+ nodes deployed
2012-03-12
We have finished deploying the first batch of 110 nodes. Currently, we are conducting long-term connectivity experiments and waiting for additional 90 mobile nodes.First nodes deployed
2012-02-06
We have just deployed 11 nodes in room 4280 on the third floor. 99 nodes are left to be deployed in 9 rooms during the next weeks.110 sensor nodes arrived
2011-12-22
Today, we received the first batch of 110 sensor nodes. Soon, we will start deploying them to create a 200-node testbed in the end.TOSN paper preprint online
2011-11-26
A preprint of our first paper "A Case for Hierarchical Routing in Low-Power Wireless Embedded Networks," which has been accepted for publication in ACM Transactions on Sensor Networks, is now available for download from the publication section. Read more...Master's students recruited
2011-07-07
We have finished the 2011 recruitment process. We received 9 high-quality applications. Unfortunately, we had to limit the number of students admitted to the project. Watch out for the next recruitment in 2012. Read more...Presentations for Master's students
2011-05-19
We have scheduled two presentations advertising the project to prospective and current Master's students. The presentations will take place on Thursday, June 2, 2011. The first one is at 12:15 in room 4070 and the second is at 13:15 in room 3120 of the Faculty of Mathematics, Informatics, and Mechanics of the University of Warsaw.Recruting Master's students
2011-05-17
The recruitment process of the Master's students who are willing to participate in the project has started. Read more...Project website operational
2011-05-13
The initial version of the project website has been finished. It is now online.Research Subject
One of the fundamental problems associated with making wireless sensor nodes a part of the Internet, which is also the subject of this project, is developing point-to-point routing protocols appropriate for sensornets. A routing protocol is responsible for finding paths in a network along which nodes can exchange data. In a typical network, a node can communicate directly only with a tiny subset of all nodes, called the node's neighbors: in the Internet, node A's neighbors are the nodes connected to A with network cables; in a sensornet, they are the nodes within A's radio range. Therefore, to send a data packet to a distant nonneighbor node, a node first transmits the packet to one of its neighbors. The selected neighbor then forwards the packet to one of its own neighbors, and so on, until the packet reaches the distant destination node. The task of a routing protocol is selecting at each forwarding node the next-hop node on the packet's path.
Main Problems
What makes the research subject interesting is the fact that sensornets have different routing requirements than traditional networks.
An individual sensor node is required to be tiny and inexpensive, and to work unattended for months. This can be achieved only if the node is simple and ultra-low power, which, however, entails severe constraints on the node's resources, including memory, processing, an communication bandwidth (see the table).
| Metric | Chronos | G-Node | TelosB |
|---|---|---|---|
| CPU Frequency | 20 MHz | 8 MHz | 16 MHz |
| RAM | 4 KB | 8 KB | 10 KB |
| ROM | 32 KB | 116 KB | 48 KB |
| Radio throughput | 500 kbps | 500 kbps | 250 kbps |
| Receive sensitivity | -112 dBm | -112 dBm | -94 dBm |
Due to such severely constrained resources, the information maintained by each sensor node for the purpose of routing (the routing state) has to be very small. Small routing state, however, makes it extremely difficult to ensure that packets are forwarded along short paths. Moreover, guaranteeing small routing state is difficult in large networks.
At the same time, most sensornet applications require hundreds or even thousands of nodes in a single network. To work in such a massive network, a routing protocol has to be scalable, which is problematic with resource-constrained nodes. For the same reason, the protocol should operate with minimal human attention. To begin with, it should be self-organized to a large extent, meaning that nodes should autonomously discover their neighbors and gradually build up their local routing state, Furthermore, whenever some nodes fail or run out of power, or some other nodes lose wireless connectivity due to changes in the environment, interference, or mobility, the nodes affected by such a change should automatically repair their local routing state. The negative effect of the change and the repair activities on routing should be local only, allowing the great majority of nodes to continue exchanging data without disruption. Again, selforganization, self-management, and robustness are difficult in a large network of resource-constrained nodes.
Our team is working on the solutions to the problems such as the ones above. In particular, we are currently building a wireless sensor network at the Institute of Informatics. I want to join...
