Body Area Sensor Network: MAC

Type: Semester thesis
Students: Michel Estermann
Advisor: Clemens Lombriser
Project: e-SENSE

In this semester project several medium access control (MAC) protocols designed for wireless networks in general and wireless sensor networks in particular are studied. With a communication test, the communication range, reliability and usability of the short range radio used in the Wearable Sensor Package created at the Electronics Laboratory of ETH Zurich has been tested and based on the results, a MAC protocol suitable for a Body Area Sensor Network (BASN) of such sensor packages was chosen. The primary goal of the MAC protocol for the BASN is energy conservation as the sensor packages should be able to collect data for a long time without the need to change or recharge the battery. The MAC protocol presented in this thesis is based on S-MAC and T-MAC. However the protocol is modified to overcome the limitations but also to exploit the features of the radio chip used. The sensor nodes follow a low duty-cycle schedule in order to conserve energy and neighbouring nodes form virtual clusters following an agreed common schedule as in S-MAC. To allow carrier sensing a common broadcast address and channel is used to exchange synchronization, request to send and clear to send messages. For the data transmission a negotiated and dedicated channel is used.