Traffic-Adaptive CFP Extension for IEEE 802.15.4 DSME MAC in Industrial Wireless Sensor Networks

This paper presents a traffic-adaptive contention-free period (CFP) extension (TaCFPext) protocol for IEEE 802.15.4 deterministic and synchronous multichannel (DSME) medium access control (MAC), which aims to satisfy the traffic adaptability requirement of industrial wireless sensor networks (IWSNs). The legacy DSME standard has limitations in accommodating highly varying load IWSNs due its fixed multi-superframe structure. TaCFPext enables node adaptively use contention (CAP) as an extended CFP (extCFP) on demands loads distributed manner. starts when it determines that current is insufficient accommodate load. Then, selects CAP be used extCFP, allocated guaranteed time slot (extGTS). When decreases, extGTS deallocated before GTS CFP, extCFP returns again. An experimental simulation was performed verify superiority TaCFPext. results demonstrated outperforms aggregate throughput average delay under various conditions.