BodyT2Throughput and Time Delay Performance

Assurance for Heterogeneous BSNs

Zhen Ren, Gang Zhou, Andrew Pyles, Mathew Keally, Weizhen Mao, Haining WangCollege of William and Mary

presented by 姚俊鹏

Outline

• Motivation• Problem Definition and Analysis• BodyT2 Design• Performance Evaluation• Conclusions

BSNbody sensor (mote)

aggregators

Data Center

Outline

• Motivation• Problem Definition and Analysis• BodyT2 Design• Performance Evaluation• Conclusions

Motivation-requirements(1)

• Applications that are performance-critical

• Requiring stringent throughput and time delay performance assurance

Smart healthcare Assisted living Emergency response

Interactive controlsAthletic performance evaluation

Motivation-research challenges

• Irregular BSN link quality.– Available resources must be adaptively rescheduled

according to efficiency and cost.

• Heterogenous BSN radio platforms.– Need to achieve the performance assurance in a

radio-agnostic manner.

Motivation-existing works

• Provide statistical throughput and/or time delay performance assurance.

• provide best effort solutions for enhancing throughput and/or reducing time delay.

• Provide either throughput or time delay performance assurance, but not both.

Based on an individual-polling scheme.

Motivation-goal

• Propose a novel and efficient radio agnostic solution for heterogeneous BSNs.

• Allows different data streams to request different throughput and time delay performance assurances.

Outline

• Motivation• Problem Definition and Analysis• BodyT2 Design• Performance Evaluation• Conclusions

Problem Definition and Analysis-outline

• Group-Polling v.s. Individual-Polling

• Throughput Assurance• Joint Assurance of Throughput and Time

Delay

Group-Polling vs Individual-Polling

• Individual-polling– Each data packet is preceded by a polling packet– Not appropriate for practical radio-agnostic system

deployment

• Group-polling– A packet train following a single polling packet

• Efficiency( fewer polling packets)• Catering to radio-agnostic BSN designs

VMAC ： abstracts common MAC behaviors with time-domain parameters: T(minPkt) and T(maxPkt)kPkt TT max

PktkPkt TTT maxmin

Throughput Assurance

• data steam specifies its throughput requirement

• decide the time schedule for each data stream

P problem

ib

Joint Assurance of Throughput and Time Delay

• data steam i on sensor mote k specifies its throughput requirement as– The requested time delay bound– The througput requirement– The priority

• Specify how much time each stream on mote uses

• NP-hard problem

),,( ,,, ikikik pdb

ikb ,

ikd ,

ikp ,

Outline

• Motivation• Problem Definition and Analysis• BodyT2 Design• Performance Evaluation• Conclusions

BodyT2 Design-outline

An empirical solution for practical system

deployment.

• Admission Control

• Time Resource Scheduling

• Enforcing Time Schedule on VMAC

Admission Control

• Required time for satisfying all streams’ requests

Pktk TTkPTTkD max),(),( Tnumber of data packets

number of polling packetsavailable time

Admission Control

• The minimum required time for sending data and polling packets for mote k

The maximum gap allowed

)2.(),(),(),( maxminmin Pktk TTkPTTkDTkS

)1.(),(

),(max

minPktk

k

TG

TTkDTTkP

)(),(),( maxPktkk TGTkPTTkDT

Admission Control

• necessary condition of admission control

• sufficient admission condition

k

kS )3.(1)1,(min

)4.(1))},({max),(( maxmin Pktk

kk

TTkPTTkD

accept decision is made;all data streams are finally rejected and removed

algorithm for scheduling the next packet train

The most recently scheduled packet train

We give mote k1’s packet train j a schedule if and only if we can foresee that any other mote(k2) can also have its packet train j scheduled.

jkjkjk ststst ,2,3,1

algorithm for scheduling the next packet train

• Time between A and D should be long enough to schedule B and C

)6.(),()),((3

1211123332 ,1,,,1min1,,3min k

jkjkkkjkjkkkjkjk etstTRetstkSTRetstkS

• Make sure enough room to schedule packet train A)7.()),(( ,max1,,1 11111 cjkPktkkjkjk tetTTRetetkD

• Make sure A and previous packet train j-1 is bounded by Gk1

)8.()),((1111111 max1,,11,, kPkekkjkjkjkjk GTTRetetkDetet

)5.()),(( max1,,1,, 11 Pktkkjkjkjkjk TTRetetkDstet

Time Resource Scheduling

• Sequentially computes the time allocated to each packet train.

• QoS data– requires throughput and time delay guarantee

• The best effort data– does not

Enforcing Time Schedule on VMAC

• Located on both the aggregator and motes.

• Extended VMAC– Checks the remaining allocated time– Checks the specified time delay constraint for each

packet.– Notifies the aggregator to terminate packet train if no

packet to send.

VMAC on aggregator

• Sends polling message with the allocate time length

).( ,,max,,, ' jkjkPktjkjkjk etstTstetPL

• Indicate time period for motes’ best effort communication

._ max, Pktjk Ttimecurentst

VMAC on motes

• Compute the amount data of each stream

• Organize data into packet train with earlier deadlines

• Check before send packet– remaining allocated time <– deadline > current time +– only QoS data packet remaining

>>termination of the packet train

PktTmax

kT

Outline

• Motivation• Problem Definition and Analysis• BodyT2 Design• Performance Evaluation• Conclusions

Performance Evaluation-outline

• TelosB Mote Lab Tests

• Real Body Experiments

Performance Evaluation-settings(1)

• Is compared with – The state-of-the art BodyQoS.– The best effort solution in the TinyOS 2.x.

• Performance metrics– The percentage of delivered throughput– The data packet deadline miss ratio– The average energy consumed

Performance Evaluation-settings(2)

• Interference settings

Performance Results of TelosB Mote Lab Tests

• Delivered Throughput– A higher timely delivered throughput ratio– A more stable throughput delivery ratio– Gain more performance when interference increases.

Performance Results of TelosB Mote Lab Tests

• Deadline miss ratio– Achieves an extremely low deadline miss ratio– Remains almost constantly when interference

increases.

Performance Results of TelosB Mote Lab Tests

• Energy consumption per delivered byte– Uses less energy than BodyQoS– Energy consumption remains stable when

interference increases.

Performance Results of Real Body Experiments in Android

Performance Results of Real Body Experiments in Android

Outline

• Motivation• Problem Definition and Analysis• BodyT2 Design• Performance Evaluation• Conclusions

Conclusions

• Proposes a novel approach to provide joint assurance in a radio-agnostic manner

• Based on group-polling scheme• Prove the joint throughput and time delay

assurance is NP-hard.• Demonstrate that BodyT2 achieves superior

performance over existing solutions

Thank you!

Any Questions?