A Throughput-Adaptive MAC Protocol for Wireless Sensor Networks Zuo Luo, Liu Danpu, Ma Yan, Wu Huarui Beijing University of Posts and Telecommunications Beijing, China IEEE WiCOM 2010
Outline Introduction System model TA-MAC Simulation Conclusion
Introduction All medium access control (MAC) protocols for wireless networks try to make sure that no node should interfere with other nodes
Introduction An additional consideration for wireless sensor networks is to manage radio's activity to conserve energy While traditional MAC protocols must balance throughput, delay and fairness
Introduction Energy consumption on sensor – Collision – Overhearing – Idle listening
Introduction In recent research efforts, a duty cycle is used in sensor nodes to reduce energy waste caused by idle listening – S-MAC – T-MAC
Introduction S-MAC active sleep Time active sleep Sensor A Sensor B
Introduction Drawbacks in S-MAC – Energy wasted – Packet dropped
Introduction T-MAC Time active sleep Sensor A
Introduction Drawbacks in T-MAC – Packet latency – Packet dropped
Goal Propose a new TA-MAC protocol in this paper – Adaptive contention window – BS packet
System model Duty cycle and synchronization Four way handshake Active period (AP) Contention window Transmission time of RTS Transmission time of CTS Short period between RTS and CTS Transmission time of BS
TA-MAC Adaptive contention window – Buffer threshold
TA-MAC A B C D E F Time RTSCTS RTS CTS ABC D EF BS waiting BS PS DATA ACK R C C R D DA A R C C R D DA A
Simulation Simulation setup ParameterValue Topology10 Line / 10*10 grid Active period20 ms Frame length650 ms Data packet size100 bytes Transmitting energy10 mA Receiving and idle energy4 mA Sleeping energy20 μA
Simulation result Line topology
Simulation result Line topology
Simulation result Grid topology
Simulation result Grid topology
Conclusion In this paper the authors proposed two new mechanisms to improve throughput and latency for WSNs The simulation results shows that TA-MAC protocol achieves significant trade-off on throughput and energy efficiency
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