Energy-Efficient Protocol for
Cooperative Networks
IEEE/ACM Transactions on Networking, Apr. 2011
Mohamed Elhawary, Zygmunt J. Haas
Yong Zhou
2012-07-19
Outline
Introduction
Cooperative Protocol
Protocol Robustness and Energy Efficiency
Simulation Results
Conclusions
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Introduction
 Wireless sensor networks: limited energy resources
 Cooperative transmission:
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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-andtransmitting
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Assumptions
 Sending nodes are synchronized
 Receiving power is the sum of all the signal
powers 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
sending 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
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