1. 14 July, 2008
Project: IEEE P Working Group for Wireless Personal Area Networks (WPANs)
Submission Title: [Distributed and beacon-enabled multiple access control for WBAN]
Date Submitted: [14 July, 2008]
Source: [Youjin Kim, Hyungsoo Lee, Seung Hyong Rhee, Wangjong Lee, Hyukjoon Lee, Suwon Park]
Company [ETRI/KWU] Address [161, Gajeong-dong, Youseong-gu, Daejeon, Korea]
Voice:[ ], FAX: [ ],
Re: []
Abstract: [Unique requirements of WBAN MAC have been discussed so far. In this document, some preliminary simulation results are provided and a new way of multiple access control is suggested in order to satisfy the WBAN MAC requirements.]
Purpose: [To present some preliminary results, and also to suggest a framework for the WBAN MAC and have a discussion]
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
<Kim, Rhee et al. >, <ETRI/KWU>

2. Distributed and Beacon-enabled Multiple Access Control for WBAN
14 July, 2008
Distributed and Beacon-enabled Multiple Access Control for WBAN
ETRI/KWU
<Kim, Rhee et al. >, <ETRI/KWU>

3. Outline Reservation vs. LBT
14 July, 2008
Outline
Reservation vs. LBT
Which one is better for multiple access control for WBAN?
A framework for WBAN MAC
How to satisfy the unique requirements?
Distinctive features of proposed MAC
Control channel with beacons
Distributed reservation by outbody devices
Unified multiple access in different bands
Channel aggregation for high-throughput applications
<Kim, Rhee et al. >, <ETRI/KWU>

4. Design Challenges for WBAN MAC
14 July, 2008
Design Challenges for WBAN MAC
Requirements of WBAN MAC
QoS assurance
Reliability and robustness
Co-existence
Energy efficiency
Great variety of traffic characteristics
Additional requirements
Unified MAC for both MICS and ISM
Scalability with a large number of devices
Security
<Kim, Rhee et al. >, <ETRI/KWU>

5. How to access the channels?
14 July, 2008
How to access the channels?
MICS
402
405
[MHz]
300 KHz
Channels in MICS band
Narrow band
Non-overlapping
Multiple access is controlled by LBT among
Medical devices
METAIDS (Meteorological aids service) devices
<Kim, Rhee et al. >, <ETRI/KWU>

6. Reservation vs. LBT (1 channel)
14 July, 2008
Reservation vs. LBT (1 channel)
Attribute
Value
Superframe
5ms
CTA
2ms
Bandwidth
0.3Mb
Traffic
CBR
Packet Size
10 bytes
<Kim, Rhee et al. >, <ETRI/KWU>

7. Reservation vs. LBT: Observation 1
14 July, 2008
Reservation vs. LBT: Observation 1
Reservation outperforms LBT in most cases by avoiding collisions
<Kim, Rhee et al. >, <ETRI/KWU>

8. Reservation vs. LBT (2 channels)
14 July, 2008
Reservation vs. LBT (2 channels)
<Kim, Rhee et al. >, <ETRI/KWU>

9. Reservation vs. LBT: Observation 2
14 July, 2008
Reservation vs. LBT: Observation 2
Due to the listening periods, the throughput of LBT is degraded
<Kim, Rhee et al. >, <ETRI/KWU>

10. Channel Plan One fixed channel for control
14 July, 2008
Channel Plan
One fixed channel for control
The remaining band is for data transfer
Dynamic and distributed spectrum allocation
MICS
402
405
[MHz]
Control channel
Data channels
<Kim, Rhee et al. >, <ETRI/KWU>

11. 14 July, 2008
Control Channel
The first (outbody) device select a channel for the control purpose
It avoids channels in use by listening
Control channel
MICS
402
405
[MHz]
Metaids in use
<Kim, Rhee et al. >, <ETRI/KWU>

12. Beacon Slots One beacon slot for one data channel
14 July, 2008
Beacon Slots
One beacon slot for one data channel
Outbody devices reserve data channels via beacons
Control channel
Data channels
frequency
time
Beacon superframe
<Kim, Rhee et al. >, <ETRI/KWU>

13. 14 July, 2008
Channel Aggregation
Outbody devices may reserve several channels via beacons
Various traffic types can be satisfied by the channel aggregation
frequency
time
Beacon superframe
Data channels
Control channel
<Kim, Rhee et al. >, <ETRI/KWU>

14. Is Channel Aggregation Better?
14 July, 2008
Is Channel Aggregation Better?
Attribute
Value
Superframe
12.4ms
Data Transmit Period
11.5ms
Bandwidth
0.9Mb / 0.3Mb
Traffic
CBR
Packet size
10 bytes
<Kim, Rhee et al. >, <ETRI/KWU>

15. Simulating the Channel Aggregation
14 July, 2008
Simulating the Channel Aggregation
High-throughput applications can benefit by channel aggregations
<Kim, Rhee et al. >, <ETRI/KWU>

16. Distributed Reservation among Outbody Devices
14 July, 2008
Distributed Reservation among Outbody Devices
Control channel
frequency
outbody
inbody
<Kim, Rhee et al. >, <ETRI/KWU>

17. Superframe Structure Communications initiated by outbody device
14 July, 2008
Superframe Structure
Communications initiated by outbody device
Inbody device first listens to the control channel, and then goes to the designated channel
Data superframe BP
In → Out
Sleep BP
In → Out
time
time
Beacon superframe
<Kim, Rhee et al. >, <ETRI/KWU>

18. Unified Access Control in Different Bands
14 July, 2008
Unified Access Control in Different Bands
Non-overlapping channels are also assumed in ISM band
Same way of multiple access control in both bands
MICS
402
405
[MHz]
300 KHz
ISM
2400
2483.5
[MHz]
several MHz
<Kim, Rhee et al. >, <ETRI/KWU>

19. Single MAC for Two PHYs: Example
14 July, 2008
Single MAC for Two PHYs: Example
WBAN MAC
WBAN MAC
MICS PHY
ISM PHY
MICS PHY
ISM PHY
outbody
inbody
MICS 1 2 3 4 5 6 7
402
405
[MHz]
ISM 11 12 13 14 15 16 17
2400
2483.5
[MHz]
<Kim, Rhee et al. >, <ETRI/KWU>

20. Advantages of the Beacon-enabled MAC
14 July, 2008
Advantages of the Beacon-enabled MAC
The beacon-enable MAC satisfies most requirements of WBAN MAC
Requirements of WBAN MAC
QoS assurance
Reliability and robustness
Co-existence
Energy efficiency
Great variety of traffic characteristics
Debatable, but also strongly preferred
Unified MAC for both MICS and ISM
Scalability with a large number of devices
Security
<Kim, Rhee et al. >, <ETRI/KWU>

21. Synchronous Power Management: IEEE 802.15.4
14 July, 2008
Synchronous Power Management: IEEE B B
GTS 2
GTS 1
inactive
Contention Access Period(CAP)
Contention Free Period(CFP)
BI (Beacon Interval)
aBaseSuperframeDuration * 2BO symbols
15.4 devices
May be in a sleep state during beacon intervals
Should periodically listen the beacons
Weak points of synchronous mechanism
One may scan a whole beacon interval in order to catch a beacon
Lower duty cycle requires expensive reference crystals
<Kim, Rhee et al. >, <ETRI/KWU>

22. Asynchronous Power Management
14 July, 2008
Asynchronous Power Management
Node 1
listen
sleep
listen
sleep
listen
Node 2
listen
sleep
listen
sleep
Wakeup schedules can differ
A couple of asynchronous mechanisms are studied in literature
B-MAC
WiseMAC
<Kim, Rhee et al. >, <ETRI/KWU>

23. Efficient Asynchronous Power Saving
14 July, 2008
Efficient Asynchronous Power Saving
(Inbody) device scans only the beacon superframe, not the long superframe at its wakeup state
Control channel
frequency
time
dev1
dev2
<Kim, Rhee et al. >, <ETRI/KWU>

24. doc.: IEEE 802.15-<doc#>
<month year>
doc.: IEEE <doc#>
14 July, 2008
References
F. Shu and G. Dolmans, MAC Design Issues and Wake-up Radio for Wireless BANs, IEEE , May 2008
M. Patel, The MAC Protocol Requirements for BAN, IEEE , Jan. 2008
S. Lee and Y. Yoon, MAC requirements for the BAN, IEEE , July 2007
“MAC and PHY specifications for low-rate wireless personal area networks,” IEEE Std , IEEE, 2003
<Kim, Rhee et al. >, <ETRI/KWU>
<author>, <company>