doc.: ieee 802.15- submission project: ieee p802.15 working group for wireless personal area...

doc.: IEEE 802.15-<doc#>

Submission

Project: IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANs)Project: IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANs)

Submission Title: [The MAC Protocol Requirements for BAN]Date Submitted: [14 January 2008]Source: [Maulin Patel] Company [Philips]Address [345 Scarborough Rd., Briarcliff Manor, NY 10510]Voice:[+1 914-945-6156], FAX: [+1 914-945-6330], E-Mail:[[email protected]]

Abstract: [This document presents key requirements for the MAC protocols of BAN]

Purpose: [To stimulate discussion on the MAC protocol requirements for BAN]

Notice: This document has been prepared to assist the IEEE P802.15. It is offered as a basis for discussion and is not binding on the contributing individual(s) or organization(s). The material in this document is subject to change in form and content after further study. The contributor(s) reserve(s) the right to add, amend or withdraw material contained herein.Release: The contributor acknowledges and accepts that this contribution becomes the property of IEEE and may be made publicly available by P802.15.


Submission

Introduction

• Low power MAC protocols typically – Trade-off throughput, delay, QoS and scalability

– For energy efficiency

• In the case of BAN applications energy efficiency is certainly a major issue, however, delay guarantee, fault-tolerance, QoS support and scalability are equally important


Submission

Key observations: Data traffic• Dominant traffic is periodic data• Typically, the data is transferred between a pair of

devices– Glucose sensor and insulin pump

– Ipod and headset

• Data traffic is asymmetric– From ECG sensors to an aggregator

– Cell phone to hearing aid

• Dissimilar applications do not communicate– Entertainment applications need not communicate with healthcare

applications

– ECG devices need not communicate with Camera-pill

– Nerve-stimulator need not communicate with insulin pump


Submission

Key observations: Network characteristics• Transmission range

– Typically 3 meter– Extendable up to 5 meters

• Most devices are in direct communication range of each other– Network diameter is very small– In scenarios where direct communication is not possible due to

body shadowing, 2 hops would be sufficient to reach any device

• Global topology information is easily available• Hidden and exposed terminal problems are less

likely• Spatial reuse is almost impossible


Submission

Key observations: Frequency band• Lower frequency bands (MICS/MEDS, 400 MHz)

– Suitable for implanted devices • Better propagation characteristics

• Limited throughput

• Not suitable for high data rate applications

• Higher frequency bands (e.g. 2.4, 5 GHz) – Suitable for wearable devices– Not suitable for implanted devices due to heavy path loss

• Challenge: Single unified QoS enabled MAC protocol for wearable and implantable devices– To comply with the duty cycle requirement of MICS/MEDS band

• Management and control overhead at higher frequencies

• Use MICS/MEDS band primarily for data communication


Submission

Energy Efficiency• Energy efficiently is the fundamental design goal

• Energy can be saved by – Minimizing idle listening

– Duty cycling the receiver between the listen and the sleep state

• Dynamic and adaptive duty cycling that can match the latency requirement and traffic load while maintaining low power operation

Time

SleepAwake/Listen

Wake up interval


Submission

Energy Efficiency (Cont’d)• To improve energy efficiency minimize

– Overhearing

– Collisions

– Control overhead

• Make reservation based access as a primary mode of medium access– Dominant traffic is periodic data

– Knowledge of global topology can be easily acquired

– Reservation complements QoS

• Shift in the design philosophy from primarily contention based to primarily reservation based


Submission

Scalability• Scalability is a key design goal• Duty cycle should be scalable from

0.001% upto 100%• Network size should be scalable up to

256 devices• Support for frequent and quick device

joining is required– Emergency room usage– Trauma unit


Submission

Co-existence• Multiple BAN applications can co-exist on the

same channel– Glucose sensor and insulin pump– ECG sensors and aggregator– Camera-pill and image collector

• Different applications need not communicate at application level

• MAC level coordination is required for harmonized coexistence

• Synergy among different applications is the key for desired QoS


Submission

Co-existence (Cont’d)

• Multiple BAN may move in and out of range of each other due to mobility – Hospital wards, emergency rooms, subways, music

concerts, theaters etc.

• Simultaneous coordinated operation of multiple co-located BANs on the same channel

• MAC protocol support for seamless network merging and partitioning

• Support for medium reservation across devices and networks is highly desirable


Submission

QoS• Support for

– Real time communication– Alarm/urgent messages– Reliable connection in crisis situation– Congestion control – Admission control

• MAC level support for channel migration • Robustness, reliability and fault tolerance are

key differentiators for BAN– Strong error correction codes– Reservation based access– Acknowledgements, retries– Ability to isolate and recover from failures


Submission

QoS• Medical applications demand strict QoS

guarantee• IEEE 802.11e defines 4 access categories

– Voice, Video, Background and Best Effort • BAN requires new access categories

– Delay guarantee– Bandwidth guarantee– Higher priority for medical applications– Higher priority for low energy/small buffer size devices

• i.e. implants

• Judicious mix of reservation based and contention based access policies are required to support medical and CE applications


Submission

Conclusion

• BAN MAC has unique requirement– Energy efficiency– Scalability– QoS– Reliability– Co-existence– Fault tolerance

• Novel techniques are needed to address these requirements

doc.: ieee 802.15- submission project: ieee p802.15 working group for wireless personal area...

Documents