IEEE802.15.4 based efficient beaconing MAC for real-time aerospace applications

In this paper a summary is given of the ongoing research work at Vikram Sarabhai Space Centre, Trivandrum on Wireless Instrumentation System (WIS) for Satellite Launch Vehicle applications. WIS is based on the physical layer (PHY) of IEEE802.15.4, Low Rate Wireless Personal Area Networks Standard (WPAN). However the researchers have pointed out the unsuitability of available 802.15.4 standard in terms of scalability, bandwidth efficiency, latency and interference issues. Since the IEEE802.15.4 beaconing Medium Access Control (MAC) can allocate a maximum of only seven Guaranteed Time Slots (GTS) for periodic data transmission, the number of sensor nodes will be limited and bandwidth under utilization problems can occur. In this paper, a new statically assigned GTS scheme is presented to allow more devices to share the bandwidth within the same period more efficiently. Experimental results reveal that proposed beaconing MAC with IEEE802.15.4 PHY works efficiently both in terms of guaranteed delay and bandwidth utilization and can be used for real-time aerospace applications even with a low speed micro controller.