MAC specifications for a WPAN allowing both energy saving and guaranteed delay* - Part B: Optimization of the intra-star exchanges for MaCARI

Industrials have been increasingly interested in sensor and actuator networks to monitor and control their installations. The recent IEEE 802.15.4 standard has been developed to address vital issues of these networks, such as limited battery power and low processing capabilities. However, the standard does not meet all the requirements of industrial networks. For example, only some of the IEEE 802.15.4 nodes save energy, and the delay for a sensor to activate an actuator is not bounded. Our research on energy-efficient MAC protocol is divided into two parts: Part A consists in introducing a flexible, synchronized treebased MAC protocol called MaCARI and Part B deals with optimizations that can be performed within each star. This paper focuses on Part B, that is, on the intra-star MaCARI protocol. Our proposal is an incremental protocol with different options which increase respectively the previous one in terms of bandwidth and energy saving. A hardware prototyping of the last option has been done in order to validate our proposal.