FINAL.La b RC-MAC : A Receiver-Centric MAC Protocol for Event-Driven Wireless Sensor Networks Pei Huang, Chen Wang, Li xiao Department of Computer Science and Engineering Michigan State University 학기 유비쿼터스 네트워크 발표 Presenter : Jiheon Kang IEEE Transaction on Computers,

FINAL.La b Outline Motivation Overview Design Details Performance Evaluation Conclusion & Critics 2

FINAL.La b Motivation Providing high throughput without sacrificing the energy efficiency (in heavy traffic load) Problem: Channel contention due to node’s simultaneous needs of data transmission Solution: Reduce collision, eliminate random backoff –Receiver-centric medium access scheduling –Distributed channel assignment 3

FINAL.La b Overview Operates as “pulling” data rather than the traditional pattern of “pushing” data (scheduling message, ID) Receiver is able to schedule its children’s data transmission by reusing the ACK(broadcast nature) 4

FINAL.La b Adapt to Low Duty Cycle 5

FINAL.La b Medium Access Scheduling 6 Heavy traffic load, high throughput and low latency are m ore critical than energy efficiency (Full Active mode) The total active period can be shortened if data are deli-v ered faster Attach bandwidth demand information to data packets

FINAL.La b Contention between Sets 7 Assign different parent-children sets different channel to gather data simultaneously - Common channel(duty-cycling), data gathering channel(full-active), data forwarding channel Dynamic adjustment of scheduling cycle length for fairness

FINAL.La b Performance Evaluation 8

FINAL.La b Performance Evaluation 9

FINAL.La b Conclusion 10 Improving the throughput and the fairness under heavy tr affic load Receiver-centric scheduling saves backoff time & reduce channel collision Multi-channel reduces the interference between parent-c hildren set