Tuyển tập báo cáo các nghiên cứu khoa học quốc tế ngành hóa học dành cho các bạn yêu hóa học tham khảo đề tài: Analysis of TDMA scheduling by means of Egyptian Fractions for real-time WSNs | Torfs and Blondia EURASIP Journal on Wireless Communications and Networking 2011 2011 37 EURASIP Journal on . httpy content 2011 1 37 Wireless Communications and Networking a SpringerOpen Journal RESEARCH Open Access Analysis of TDMA scheduling by means of Egyptian Fractions for real-time WSNs Wim Torfs and Chris Blondia Abstract In Wireless Sensor Networks WSNs Time Division Multiple Access TDMA is a well-studied subject. TDMA has however the reputation of being a rigid access method and many TDMA protocols have issues regarding the entering or leaving of sensors or have a predetermined upper limit on the number of nodes in the network. In this article we present a flexible TDMA access method for passive sensors that is sensors that are constant bitrate sources. The presented protocol poses no bounds on the number of nodes yet provides a stable framing that ensures proper operation while it fosters that every sensor gets its data on time at the sink and this in a fair fashion. Even more the latency of the transmission is deterministic and thereby enabling real-time communication. The protocol is developed keeping in mind the practical limitations of actual hardware limiting the memory usage and the communication overhead. The schedule that determines when a sensor can send can be encoded in a very small footprint and needs to be sent only once. As soon as the sensor has received its schedule it can calculate for the rest of its lifetime when it is allowed to send. I. Introduction A Wireless Sensor Network WSN is an interesting type of network which can be used for several objectives. For instance data monitoring is such application where sensors send data at regular intervals. Such networks consist of devices that are considered to be small low cost and with limited resources such as a low amount of working and program memory low processing power and a low battery capacity. Such kind of networks are presumed to work in an unattended .
