1. doc.: IEEE 802.15-<doc#>
<month year>
doc.: IEEE <doc#>
<May 2009>
Project: IEEE P Working Group for Wireless Personal Area Networks (WPANs)
Submission Title: [Versatile MAC for Body Area Network ]
Date Submitted: [4 May, 2009]
Source: [J.S Yoon, Gahng S. Ahn, Myung J Lee, Seong-soon Joo] Company [CUNY, ETRI]
Address [140th St. and Convent Ave, New York, NY, USA ]
Voice:[ ], FAX: [], ,
Re: [Versatile MAC for BAN proposal responding to TG6 Call for Proposals ( tg call-proposals) ]
Abstract: [This document describes a Versatile MAC that is being proposed to the TG6 group ]
Purpose: [Discussion in Task Group ]
Notice: This document has been prepared to assist the IEEE P 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 P
<J.S.Yoon>, <CUNY, ETRI>
<author>, <company>

2. Versatile MAC for Body Area Networks
<month year>
doc.: IEEE <doc#>
<May 2009>
Versatile MAC for Body Area Networks
June S Yoon, Gahng S Ahn, Myung J Lee, Seong S. Joo
CUNY, ETRI
<J.S.Yoon>, <CUNY, ETRI>
<author>, <company>

3. doc.: IEEE 802.15-<doc#>
<month year>
doc.: IEEE <doc#>
<May 2009>
Outline
Motivation
Challenges
Versatile MAC Overview
Functionalities of Each Period
AD, CAP, Beacon, DTP, Options
Energy saving
Prioritization
Performance
Conclusion
<J.S.Yoon>, <CUNY, ETRI>
<author>, <company>

4. To design a simple MAC protocol to support various QoS for
<May 2009>
Motivation
To design a simple MAC protocol
to support various QoS for
Body Area Networks
<J.S.Yoon>, <CUNY, ETRI>

5. MAC Design Challenges QoS Assurance Flexibility Energy efficiency
<May 2009>
MAC Design Challenges
QoS Assurance
High reliability and guaranteed latency requirement for real time data, especially vital signs
Need deterministic structure
Special care for emergency reaction alarm
Flexibility
Support various types (periodic, non-periodic, medical, entertainment…) of traffic, data rate and PHYs
 Instantly adaptable to application’s requirements
Energy efficiency
Less energy consumption especially for implanted device
Need efficient active/inactive scheduling
<J.S.Yoon>, <CUNY, ETRI>

6. Versatile MAC Overviews
<May 2009>
Versatile MAC Overviews
<J.S.Yoon>, <CUNY, ETRI>

7. Versatile MAC Features
<May 2009>
Versatile MAC Features
Versatile
Best breed of Contention based and TDMA
Supports various (burst, periodic, continuous) types of traffic
Straightway reservation
Fast reservation and prompt adaption
Latency reduction for delay sensitive real time data
Emergency data transmit slot
Highly adaptable to abrupt emergency data
Support high QoS and reliability
Priority supported
Simple, easy to implement
<J.S.Yoon>, <CUNY, ETRI>

8. BSF (BAN Superframe) Ad (Advertisement) CAP Beacon
<May 2009>
BSF (BAN Superframe)
Ad (Advertisement)
Synch, interval, address
CAP
Reservation, Non-periodic data
Beacon
Synch, length of slot, reservation status announcement
DTP (Data Transmit Period)
DTS (Data Transmit Slot)
Continuous, Periodic data
ETS (Emergency Data Transmit Slot)
Emergency data & Periodic data
<J.S.Yoon>, <CUNY, ETRI>

9. <month year>
Flexible BSF
BSF flexibly adjusts its length in accordance with requirements of sensor nodes
<J.S.Yoon>, <CUNY, ETRI>

10. Functionalities of Each Period
<May 2009>
Functionalities of Each Period
<J.S.Yoon>, <CUNY, ETRI>

11. <May 2009>
Advertisement
The beginning of BSF (BAN Superframe) followed by contention access period
Ban Coordinator (BC) broadcasts it at the beginning of BSF and it contains basic information such as
Synchronization
BC ID
Ad Interval, length of periods
A newly joined node adjusts its clock, gets information on BC and BSF
<J.S.Yoon>, <CUNY, ETRI>

12. CAP Contention access period Data Transmission
<May 2009>
CAP
Contention access period
Backoff and CCA to avoid collision
Prioritized back-off and CCA to serve higher priority first
Data Transmission
Command frames exchange for DTS reservation
Non-periodic data including alarm and periodic data failed to reserve DTS can be sent
BC collects all the DTS requests and sort them according to their priorities and slot availability
Allocate from first available slot based on the priority order to prevent DTS shortage
Lower priority slots may be preempted by higher priority data
<J.S.Yoon>, <CUNY, ETRI>

13. Beacon BC Broadcasts beacon before DTP
Notifies sync, interval, length, DTS reservation status
All the nodes that reserved DTS should listen beacon every AI to check reservation status changes
Sequential ‘Ad-CAP-Beacon’ enables straightway slot reservation and prompt accommodation to changes
<J.S.Yoon>, <CUNY, ETRI>

14. Straightway Reservation & Transmission Why ? How?
<month year>
Straightway Reservation & Transmission Why ? How?
In a life critical situation, e.g. patient in ER, wounded soldier in battle field, urgent reporting after initial placement of sensors is as important as emergency alarm
Place Ad  CAP  Beacon in a row enables urgent transmission
<J.S.Yoon>, <CUNY, ETRI>

15. <May 2009>
Data Transmit Period
TDMA Period for the latency-critical continuous and periodic data
BC allocates DTS first and then ETS if no more DTS is available
Since ETS is dedicated slot for Emergency data, the node assigned to ETS performs CCA before its transmission so as to avoid collision with Emergency data
<J.S.Yoon>, <CUNY, ETRI>

16. ETS for Emergency Alarm
<May 2009>
ETS for Emergency Alarm
ETS (Emergency Data Transmit slot)
Contention access period
Number of slot is configurable and evenly distributed throughout DTP period
If any, emergency data is transmitted at ETS while a node assigned to this slot performs CCA
Emergency alarm can be sent in CAP, ETS, and CAP Extension whichever available first
Enables urgent transmission for abrupt Emergency alarm
<J.S.Yoon>, <CUNY, ETRI>

17. Options ECAP (CAP Extension) Batch ACK Delayed ACK
<May 2009>
Options
ECAP (CAP Extension)
The duration between the ends of DTP and next advertisement
If power is not a concern for BC, it can stay awake and extend CAP
All kinds of data can be transmitted including retransmission
Batch ACK
Ack at the last active slot for all data transmission in DTP
Delayed ACK
Ack for multiple-slot transmission from a same source
<J.S.Yoon>, <CUNY, ETRI>

18. <May 2009>
Prioritization
<J.S.Yoon>, <CUNY, ETRI>

19. BAN Data Prioritization
<May 2009>
BAN Data Prioritization
Prioritization based on QoS (latency) requirement
Priority 0: Emergency reaction alarm (CAP, ETS)
Emergency vital signs, Battery depletion, ...
Priority 1: Medical Continuous data (DTS)
Latency critical data
E.g. EEG/ECG/EMG
Priority 2: Medical Routine data (DTS)
Reliability critical but lesser latency requirement
E.g. Temperature, Blood pressure
Priority 3 : Non-medical Continuous data (DTS)
Video, audio
Priority 4 : Non-medical, non-time sensitive (CAP)
Priority classes are dictated by the applications
<J.S.Yoon>, <CUNY, ETRI>

20. Prioritized DTS Allocation
<May 2009>
Prioritized DTS Allocation
For Priority classes 1, 2, and 3
Priority based allocation (1)
Higher priority data served first in case of contention among different priority traffics
Priority based allocation (2)
Higher priority data can preempt lower priority if no DTS is available
This change immediately becomes effective through straightway reservation
<J.S.Yoon>, <CUNY, ETRI>

21. <May 2009>
Access Policy in CAP
Perform random back-off first then CCA before access channel
Back-off classes
Class 0: Priority 0 (Emergency alarm)
Class 1: Priority 1 and 2 (Medical)
Class 2: Priority greater than 2 (Non-Medical)
Back-off interval
The lower the priority the longer the back-off duration
<J.S.Yoon>, <CUNY, ETRI>

22. Access Policy in ETS Alarm may share ETS with Priority 1~3 data
Priority 1~3 data perform CCA first to avoid collision
Alarm also performs CCA for the case of contending among multiple alarms
CCA Duration of slot owner (fixed)
= unitCCAduration x N
Random CCA for alarm
CCA Duration of alarm
= [0, unitCCAdurtion x (N-1)]
<J.S.Yoon>, <CUNY, ETRI>

23. <May 2009>
Energy Saving
Inherent advantage of TDMA architecture for power saving over non-TDMA structure.
Coordinator
Goes into inactive If no activity is scheduled after CAP or DTP
Sensor (continuous data)
Once DTS reservation is done, the node stays inactive period except for beacon and its reserved transmit time
Sensor (routine data)
Wakeup only for report and transmit during CAP or CAP Extension whichever available first
Sensor (Alarm)
Wakeup only for report and transmit during CAP, CAP Extension or ETS whichever available first
<J.S.Yoon>, <CUNY, ETRI>

24. Summary of Versatile MAC Functionalities
<May 2009>
Summary of Versatile MAC Functionalities
<J.S.Yoon>, <CUNY, ETRI>

25. <May 2009>
Simulation
<author>, <company>

26. Simulation Scenario Simulation time: 5 min. Star topology
<May 2009>
Simulation Scenario
Simulation time: 5 min.
Star topology
1 BAN Coordinator and child nodes
Superframe size
Slot size: 7.68ms
AI: 128 slot
CAP: 8 slot
Ad & Beacon: 1 slot each
Data rate: 250Kbps
Channel model: CM3, 2.405Ghz
IEEE : BO=6, SO=3
<J.S.Yoon>, <CUNY, ETRI>

27. <May 2009>
Comparison: Reservation delay (From data generation to slot assign confirm by beacon)
Difference: 119 slots
<J.S.Yoon>, <CUNY, ETRI>

28. <May 2009>
Comparison: Emergency Alarm delay (From alarm generation to arrival at coordinator)
Simulation time: 5 min
Poisson pkt arrival rate:
- 1pkt/10sec
Frame size: 144 bit
Number of node:
-1,2,3,4,5,7,10
Number of ETS:1,3,7
15.4: BO=6, SO=3
<J.S.Yoon>, <CUNY, ETRI>

29. Throughput Simulation time: 5 min No. of ETS: 3 No. of node: 25 nodes
<May 2009>
Throughput
Simulation time: 5 min
No. of ETS: 3
No. of node: 25 nodes
-15 Periodic data node:
1pkt/sec (3.2Kbit)
- 5 Alarm: (Poisson) 1 pkt/min
(16bit)
- 5 Non-perodic data node:
(Poisson) 1pkt/5sec (32bit)
<J.S.Yoon>, <CUNY, ETRI>

30. Conclusion Versatile MAC Straightway reservation
<May 2009>
Conclusion
Versatile MAC
CAP: Contention period
DTP: TDMA period, Enables high QoS
Straightway reservation
Fast reservation, adaptation
Latency reduction
Emergency data transmit slot
Highly adaptable to abrupt emergency data
Support high QoS and reliability
Priority supported
Simple, easy to implement
A little modification to IEEE
<J.S.Yoon>, <CUNY, ETRI>