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\iteman{io-port 06024797}
\itemau{Chin, Kwan-Wu; Klair, Dheeraj}
\itemti{$E^{2}$MAC : an energy efficient MAC for RFID-enhanced wireless sensor networks.}
\itemso{Pervasive Mobile Comput. 7, No. 2, 241-255 (2011).}
\itemab
Summary: The primary aim of any anti-collision protocols is to identify tags quickly, as doing so ensures that a Radio Frequency IDentification (RFID) reader incurs minimal energy wastage and achieves high identification rate. To date, researchers have proposed various protocols to minimize tag collisions and idle slots -- key factors that determine a reader's read rate and energy expenditure. Most of these protocols, however, are designed for single reader systems. To this end, we propose $E^{2}$MAC, an energy efficient, distributed Medium Access Control (MAC) protocol for identifying and monitoring tags in RFID-enhanced wireless sensor networks. $E^{2}$MAC exploits the low power capability of a ultra-wideband transceiver and distinct pulses to address the reader collision problem. In addition, it uses ResMon, an enhanced dynamic frame slotted Aloha protocol to read and monitor tags. Lastly, $E^{2}$MAC uses a novel load balancing algorithm to amortize the cost of reading and monitoring tags to multiple readers. These $E^{2}$MAC features ensure that the contention level at each reader is kept at a minimum and distributed fairly. As a result, $E^{2}$MAC has a high reading rate and low energy consumption. In addition, $E^{2}$MAC helps in minimizing the impact of the tag orientation problem, where a tag becomes unreadable if its antenna is parallel to a reader's field lines. In particular, the use of multiple readers increases spatial diversity and hence increases the likelihood that a tag is readable by at least one reader. Our simulation results show $E^{2}$MAC to have very low energy consumption, reading delay and per-reader collision. More importantly, system designers have the flexibility to lower these metrics further with additional readers, bigger frame sizes, or by dividing tags into small groups.
\itemrv{~}
\itemcc{}
\itemut{wireless sensor networks; RFID; tag reading; anti-collision; UWB; energy efficient}
\itemli{doi:10.1016/j.pmcj.2011.01.003}
\end