MAC protocol for wireless sensor networks
Fabio Pozzo, Ileana Ghizdavescu, Anders Grauballe, Mikkel Gade Jensen, Giuseppe Calí
Wireless sensor networks consist of spatially distributed autonomous small devices, often called "motes", which cooperatively monitor, collect and exchange data from the surrounding environment.
The new motes developed at Aalborg University integrate, besides a bluetooth module supporting a one-hop connection, a low cost Industrial, Scientific and Medical (ISM) band module which makes possible to establish multi-hop connection between the motes.
The purpose of this project is to design and implement a medium access control (MAC) protocol for the ISM module of the mote platform, allowing direct communication among the motes and proving a solution to overcome possible collissions between packets during transmission.
A collision avoidance scheme with acknowledgments and carrier sensing has been designed and implemented to minimize data loss and delay, with a minimal number of retransmissions.
To test the reliability of this wireless network and as an application proposal, two mobile phones are connected to the first and the last mote in the network via the bluetooth interface, allowing them to exchange messages through the network.
The next step towards a usefull sensor network is to give the motes sensing capabilities to monitor e.g. temperature or motion in a room. The measurements can be conveyed through the network and delivered to the mobile phone of the user to inform him about environmental conditions.