Research Article

Abstract:The unique features of wireless sensor networks (WSNs) make them suitable for a wide range of applications in many dierent areas. However, with many of the protocols and algorithms used in traditional wireless networks, it is usually neither feasible nor possible to apply them directly to WSNs due to the strict resource constraints of tiny sensor nodes. Moreover, application-specic approaches for communication protocols are usually imposed since WSN applications have distinct requirements. In this study, event-driven WSN applications, where a number of sensor nodes are randomly and densely deployed in remote and dicult to reach locations, are targeted. In such applications, energy eciency and latency are crucial design parameters since replacing or recharging the batteries of sensor nodes is extremely dicult, and any sensed data should be transmitted eventually. Considering this aspect, conventional time division multiple access-based medium access control (MAC) protocols are not well suited, although there are a few MAC protocols specically designed for event-driven WSNs. In this paper, we introduce a MAC protocol, named modied bit-map{assisted (M-BMA), for event-driven WSN applications, designed by employing a new active node determination method (ANDM) and dynamic time slot allocation approach. Utilizing the proposed ANDM, we present that the M-BMA well supersedes its classical counterpart, oering up to approximately 49 % better energy usage as well as up to about 68 % fewer message delays. Key words: WSN, MAC, active node, dynamic time slot allocation 1