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TMMAC: An Energy Efficient Multi-Channel MAC Protocol for Ad Hoc

NetworksJingbin Zhang†, Gang Zhou†, Chengdu Huang‡, Sang H. Son†, John A. Stankovic†

†Department of Computer Science, University of Virginia

‡Department of Computer Science, University of Illinois

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Motivation

TMMAC: A TDMA based multi-channel MAC protocol using a single half duplex radio transceiver.

Why Multi-channel? Increase the bandwidth Most IEEE 802.11 devices can switch channels dynamically.

Why a single radio transceiver? Using multiple radio transceivers increases both the cost and energy

consumption Most IEEE 802.11 devices use a single half-duplex radio transceiver

Why TDMA? Increase the life time of the mobile devices Improve the throughput

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Contribution

Novel multi-channel MAC Energy efficient: 74% less per packet energy High throughput: 113% higher throughput Supporting broadcast efficiently.

Accurate analytical model. Dynamic ATIM window adjustment scheme.

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Outline

State of the Art TMMAC Design Analytical Model Dynamic ATIM Window Adjustment Performance Evaluation Conclusion

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State of the Art (1)

Special hardware support:Multiple radio transceivers: [Wu et al. 2000]

[Raniwala et al. 2005] [Adya et al. 2004]Busy tone: [Deng et al. 1998]FHSS: [Tang et al. 1999] [Tyamaloukas et al.

2000]

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State of the Art (2)

Single radio transceiver: Frequency negotiation: [So et al. 2004] [Fitzek et al. 2003]

[Li et al. 2003] [Jain et al. 2001]… Random number generators: [Bahl et al. 2004]:

MMAC [So et al. 2004] Time synchronization Beacon interval: ATIM window + Communication windo

w ATIM window: Frequency negotiation Communication window: Data transmission

802.11 DCF

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TMMAC Design: Overview

Similar to 802.11 PSM & MMAC: Time synchronization, Beacon interval (ATIM window + Communication

window) Different from MMAC:

Communication window is divided into time slots Both the frequency and the time are negotiated in the ATIM window ATIM window is dynamically adjusted

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TMMAC Design: Example (1)

Assumption: Two channels; The communication window contains 5 time slots

DA B C

0 0 0 0 0

0 0 0 0 0

0 0 0 0 0

0 0 0 0 0

0 1 0 0 0

0 0 0 1 0

0 0 0 0 0

0 0 0 0 0

0 0 0 0 0

0 0 0 0 0

0 0 0 0 0

0 0 0 0 0

Channel Usage Bitmaps (CUBs)

At the start of an ATIM windowSuppose node B has two packets to be sent to node C in this beacon interval.

Combined CUBs

0 1 0 0 0

0 0 0 1 0

0 1 0 0 0

0 0 0 1 0

0 1 0 0 0

0 0 0 1 0

Channel Allocation Bitmaps (CABs)

0 1 0 0 0

0 0 0 1 0

0 0 0 0 0

0 0 0 0 0

ATIM packet

OR

ATIM-ACK packetATIM-RES packet

E

Slot 2 Rec. in channel 1

Slot 4 Rec. in channel 2

Slot 2 Send in channel 1

Slot 4 Send in channel 2

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TMMAC Design: Example (2)

DA B C

0 1 0 0 0

0 0 0 1 0

0 1 0 0 0

0 0 0 1 0

0 1 0 0 0

0 0 0 1 0

0 1 0 0 0

0 0 0 1 0

0 0 0 0 0

0 0 0 0 0

E

Slot 2 Rec. in channel 1

Slot 4 Rec. in channel 2

Slot 2 Send in channel 1

Slot 4 Send in channel 2

Suppose node E has two packets to be sent to node D in this beacon interval.

ATIM packet

OR

0 1 0 0 0

0 0 0 1 0

0 1 0 0 0

0 1 1 1 0

Slot 2 Rec. in channel 1

Slot 3 Rec. in channel 2

0 0 0 0 0

0 1 1 0 0

ATIM-ACK packet

0 1 0 0 0

0 1 1 1 0

0 0 0 0 0

0 1 1 0 0

Slot 2 Send in channel 1

Slot 3 Send in channel 2

ATIM-RES packet

CABs

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TMMAC Design: Example (3)

DA B C

0 1 0 0 0

0 0 0 1 0

0 1 0 0 0

0 0 0 1 0

E

Slot 2 Rec. in channel 1

Slot 4 Rec. in channel 2

Slot 2 Send in channel 1

Slot 4 Send in channel 2

Suppose node C has one packets to broadcast to its neighbors in this beacon interval.

0 1 0 0 0

0 1 1 1 0

Slot 1 Rec. in channel 1

Slot 3 Rec. in channel 2

ATIM-BRD packet

0 1 0 0 0

0 1 1 1 0

0 0 0 0 0

0 1 1 0 0

Slot 2 Send in channel 1

Slot 3 Send in channel 2

0 0 0 0 0

0 0 0 0 1

0 1 0 0 0

0 1 1 1 1

CABs

Slot 2 Rec. in channel 1

Slot 4 Rec. in channel 2

Slot 5 Send in channel 2

0 1 0 0 0

0 0 0 1 1

1 1 0 0 0

0 1 1 1 1

Slot 2 Send in channel 1

Slot 4 Send in channel 2

Slot 5 Rec. in Channel 2

Slot 2 Rec. in channel 1

Slot 3 Rec. in channel 2

Slot 5 Rec. in channel 2

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Analytical Model

Analyze the saturation throughput of TMMAC in wireless LANs.

Built upon [Bianchi 2000], which is used to analyze the saturated throughput of 802.11.

Validated through simulations in GloMoSim.

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Impact of Time Synchronization Error2% at

maximum18% to

31%

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Motivation

There is no fixed optimal ATIM window size when the network is saturated.

A smaller ATIM window is preferred when the network is not saturated.

The dynamic ATIM window scheme used in 802.11 PSM is not applicable. [Jung et al. 2002]

Dynamic ATIM Window Adjustment

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Rules for Dynamic ATIM Window Adjustment (1)

A finite set of ATIM window sizes are used: {ATIM1, …, ATIMi, ATIMi+1, …, ATIMm} and ATIMi+1-ATIMi=lslot

The default channel is never used for data communication in the time slots before ATIMm.

The ATIM window size for the next beacon interval is piggybacked in the ATIM control packets.

Node A wants to send the packet to node B A knows B’s ATIM window size A does not know B’s ATIM window size

Dynamic ATIM Window Adjustment

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Rules for Dynamic ATIM Window Adjustment (2)

Decide whether the network is saturated.

If the network is saturated If the communication window is fully used

decrease the ATIM window size by one level If not Increase the ATIM window size by one level

If the network is not saturated, decrease the ATIM window size by one level

Dynamic ATIM Window Adjustment

>? Saturation threshold

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Simulation SettingsNumber of channels 3

Bit rate 2Mbps

Packet size 512 bytes

Channel switch delay 80us

Time synchronization error 0.1ms

Beacon interval 100ms

Network size 1000m by 1000m

Node number 200

Application layer CBR

Routing layer GF

MAC layer TMMAC, MMAC, 802.11

Communication Range 250m

Carrier sense range 500m

Performance Evaluation

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Evaluation Metrics

Aggregated ThroughputTotal throughput of all the nodes in the

network

Per packet energyThe value of total energy consumed by the

whole network divided by the total number of data packets successfully transmitted.

Performance Evaluation

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010

20304050

607080

90100

0 5 10 15 20 25 30 35 40Ti me ( second)

ATIM

Win

dow

Size

(ms

)

010

20304050

607080

90100

Numb

er o

f Pa

cket

s

ATI M Wi ndow Si zeNumber of Packets

Evaluation of Dynamic ATIM Window Adjustment (1)

Performance Evaluation

Traffic pattern

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0

2000

4000

6000

8000

10000

12000

1 2 3 4 5 6 7 8 9 10111213141516171819202122232425262728293031323334353637383940Ti me (Second)

Aggr

egat

e Th

roug

hput

(Kb

ps)

Dynami c ATI M (Per Packet Energy: 0. 0085 mWhr)ATI M=8. 57ms (Per Packet Energy: 0. 0105 mWhr)ATI M=20ms (Per Packet Energy: 0. 0128 mWhr)ATI M=31. 43ms (Per Packet Energy: 0. 0173 mWhr)

Evaluation of Dynamic ATIM Window Adjustment (2)

Performance Evaluation

Traffic pattern

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Performance vs. System Loads (1)

Aggregate throughput vs. packet arrival rate

113% more aggregated throughput

Performance Evaluation

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Performance vs. System Loads (2)

Per packet energy vs. packet arrival rate

74% less per packet energy

Performance Evaluation

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Performance vs. System Loads (3)

Aggregate throughput vs. packet arrival rate (6 channels)

84% more aggregated throughput

Performance Evaluation

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Conclusion

TMMAC exploits the advantage of both multiple channels and TDMA in an efficient way.

TMMAC achieves high communication throughput and low energy consumption.113% higher communication throughput74% less per packet energy

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Publication Jingbin Zhang, Gang Zhou, Sang H. Son, John A. Stankovic, Kamin Whitehouse, "Performance

Analysis of Group Based Detection for Sparse Wireless Sensor Networks," in Submission. Jingbin Zhang, Gang Zhou, Chengdu Huang, Sang H. Son, John A. Stankovic, "TMMAC: An E

nergy Efficient Multi-Channel MAC Protocol  for Ad Hoc Networks," 2007 IEEE International Conference on Communications (IEEE ICC'07), Glasgow, Scotland, 2007.

Jingbin Zhang, Ting Yan, John A. Stankovic, Sang H. Son, "Thunder: Towards Practical, Zero Cost Acoustic Localization for Outdoor Wireless Sensor Networks," ACM SIGMOBILE Mobile Computing and Communications Review (ACM MC2R), Special Issue on Localization Technologies and Algorithms, 2007.

Jingbin Zhang, Ting Yan, Sang H. Son, "Deployment Strategies for Differentiated Detection in Wireless Sensor Networks," Third Annual IEEE International Conference on Sensor Mesh and Ad Hoc Communications and Networks (IEEE SECON'06), Reston, VA, 2006.

Shan Lin, Jingbin Zhang, Gang Zhou, Lin Gu, Tian He, John A. Stankovic, "ATPC: Adaptive Transmission Power Control for Wireless Sensor Networks," 4th ACM International Conference on Embedded Networked Sensor Systems (ACM SenSys'06), Boulder, Colorado, 2006.

Jingbin Zhang, Gang Zhou, Sang H. Son, John A. Stankovic, "Ears on the Ground: An Acoustic Streaming Service in Wireless Sensor Networks," Fifth IEEE/ACM International Conference on Information Processing in Sensor Networks (IEEE/ACM IPSN'06, Demo Abstract), Nashville, TN, 2006.

Arsalan Avatoii, Jingbin Zhang, Sang H. Son, "Group-Based Event Detection in Undersea Sensor Networks," Second International Workshop on Networked Sensing Systems (INSS'05), San Diego, California, 2005.

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Questions?