Energy-Efficient Protocol for Cooperative NetworksIEEE/ACM Transactions on Networking, Apr. 2011Mohamed Elhawary, Zygmunt J. Haas

Yong Zhou2012-07-19

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OutlineIntroductionCooperative ProtocolProtocol Robustness and Energy EfficiencySimulation ResultsConclusions

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Introduction Wireless sensor networks: limited energy resources

Cooperative transmission: • Virtual antenna array• Diversity gain• Energy efficient

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Cooperative Protocol - CwR

Cluster head, sending cluster, receiving cluster Path width Two phases: routing (AODV), recruiting-and-transmit

ting

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Assumptions

Sending nodes are synchronized Receiving power is the sum of all the signal p

owers coming from all the senders

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CAN

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Recruiting Phase

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BER-MISO

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Protocol Robustness (1) Denote the transmission pattern of nodes in a sendin

g cluster by a binary representation bm-1 … b1 b0 according to which node j transmits if bj = 1 and does not transmit if bj = 0.

Similarly, denote the reception status of nodes in a receiving cluster by a binary representation bm-1 … b1

b0 according to which node j correctly receives the packet if bj = 1 and receives the packet in error if bj = 0.

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Protocol Robustness (2)

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Protocol Robustness (3)

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Other Protocols Disjoint-paths:

One-Path

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Failure Probability

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Energy Consumption To make the comparison of energy consumption of

any two schemes meaningful, the failure probability needs to be kept equal for the compared schemes.

Thus, the needed transmission power for each case can be calculated according to the analysis of robustness.

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Power Ratio

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Conclusions Propose an energy-efficient cooperative protocol

Analyze the robustness and energy consumption of the protocol