a dual-radio framework for mac protocol implementation in wireless sensor networks manjunath d, mun...
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ICC'2011
A Dual-Radio Framework for MAC Protocol Implementation in Wireless
Sensor Networks
Manjunath D, Mun Choon Chan, and Ananda A LNational University of Singapore
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Outline of This Talk
An overview of the background, problem, and the proposed solution
Analytical and experimental analysis of the proposed solution
Implementation and evaluation of our framework
Conclusions
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Background: Sensor Network MAC Protocols
Categories Synchronous protocols (e.g., SMAC [Infocom’02]) Asynchronous protocols
Sender-initiated techniques (e.g., BMAC [SenSys’04]) Receiver-initiated techniques (e.g., AMAC [SenSys’10])
Hybrids of synchronous and asynchronous techniques (e.g., SCP [SenSys’06])
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Problem
Even after a decade of research, sensor network MAC protocols still spend significant energy in idle-listening and/or control operations This is true even for the most recent AMAC
[Sensys’10]
Such idle-listening and control operations are inevitable These operations are part of the MAC functionality
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Proposed Solution
Our solution is based on the two key observations In typical sensor network MAC protocols,
there are two categories of operations Bandwidth-independent operations
• Durations of idle-listening and control operations are independent of the physical data rate
Bandwidth-dependent operations• Durations of transmission and reception of data packets are
functions of data rate
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Proposed Solution It is well-known that there are two types of
sensor network specific radio transceivers1. Time-wise energy efficient transceivers
2. Bit-wise energy efficient transceivers
ICC'2011
Parameter CC1000 CC2420Data rate 19.2 Kbps 250 Kbps
Tx Power 31.2 mW 52.2 mW
Rx/ID Power 22.2 mW 56.4 mW
Time-wise energy efficiency (Power)
Tx energy/bit 1625 nJ 208 nJ
Rx energy/bit 1156 nJ 225 nJ
Bit-wise energy efficiency
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Proposed Solution
Unlike existing multi-radio systems, we do not propose a new MAC protocol
We show that how a given MAC protocol can be re-implemented using dual radios so that in-evitable operations can be efficiently handled Bandwidth-independent operations are served on
time-wise energy efficient transceivers like CC1000 CC2420 like bit-wise energy efficient transceivers
are used to serve bandwidth-dependent operations
We demonstrate significant energy savings by re-implementing SMAC, BMAC, and SCP
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Proposed Solution: Analytical Analysis
In order to motivate the necessity for dual radios, we model BMAC, the most popular sensor network MAC protocol
We analyze by comparing energy consumption of single and dual-radio BMAC protocols
We mainly consider three parameters, number of nodes, load, and packet size
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Proposed Solution: Experimental Analysis
Methodology of the analysis We analyze a representative protocol from
each of the three categories of MAC protocols
Bandwidth-independent and bandwidth-dependent operations are analyzed separately
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Experimental Analysis of Bandwidth-Independent Operations
-60%
Synchronous protocols (SMAC [Infocom’02])
Power consumption of a node with 10% duty-cycling
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Asynchronous Protocols (BMAC [SenSys’04])Sender
Receiver
savings range from 37% to 46%
savings is about 60%
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Hybrid Protocols (SCP [SenSys’06])
Sender
Receiver
savings range from 50% to 55%
savings range from 69% to 81%
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Operation of RTS/CTS/DATA/ACK Exchange
Experimental Analysis of Bandwidth-Dependent Operations
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Dual-Radio Framework: Implementation
We re-implement BMAC and SCP by modifying their existing single-radio versions on TinyOS (1.x)
It is not necessary to re-implement SMAC separately Its dual-radio re-implementation results in a
operation similar to dual-radio SCP Moreover, SMAC and SCP protocols share same
synchronization procedure
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Dual-Radio Framework: Implementation
Energy saving operations are implemented on CC1000 Periodic radio wakeup, channel polling, and Tx
and Rx of preambles constitute these operations in BMAC
In SCP, such operations include achieving synchronization, radio wakeup, channel polling, and Tx and Rx of wakeup tones
Data is communicated on CC2420
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Dual-Radio Framework: Evaluation
Evaluations are carried out in two scenarios1. Using a classical set-up of a sender and a
receiver nodes
2. In a more realistic scenario of multiple nodes where not every node is in the vicinity of another
We compare dual-radio versions against single-radio versions running on CC2420
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Dual-Radio Framework: Evaluation
Evaluation results on a pair of sender and receiver nodes
state energy savings
Wake-up 55% to 64%
Idle/Rx 3% to 46%
Tx 44% to 45%
Total 36% to 47%
Dual-Radio BMAC
state energy savings
Wake-up 43% to 57%
Idle/Rx 44% to 50%
Tx 41% to 44%
Total 44% to 49%
Dual-Radio SCP/SMAC
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Dual-Radio Framework: Evaluation
Evaluation results of dual-radio BMAC on a setup of six nodes
Setup Wup (mJ) Id/Rx (mJ) Tx(mJ) Total (mJ)single-radio 102.33 3197.78 1569.67
dual-radio 62.28 1178.42 487.01 1733.97
dual-radio with power control
52.94 403.62 467.13
Sum of the energy consumed at all six nodes
-65%-81%
4874.03
928.99
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Conclusions
Idle-listening and control operations of sensor network MAC protocols are inevitable
Our dual-radio framework is efficient in serving such unavoidable operations
The framework is generic to all the mainstream categories of sensor network MAC protocols
The framework is easy-to-implement and significant savings of up to 81% is being observed