1. January 2006
Project: IEEE P Working Group for Wireless Personal Area Networks (WPANs)
Submission Title: [Mobility Issues and Their Solutions for Mesh Networks]
Date Submitted: [19 January, 2006]
Source: [Ho-In Jeon (1), Yong-Bae Kim (2), Bum-Joo Kim (2), Yongsik Shin (3)]
Company: [Dept. EE, Kyung-Won University (KWU) (1), LeiiTech Inc. (2), SKTelecom (3)]
Address: [San 65, Bok-Jung-Dong, Sung-Nam-Shi, Kyung-Gi-Do, Republic of Korea]
Voice 1:[ ], Voice 2:[ ] FAX: [ ],
Re: [This work has been supported partly by ITRC.]
Abstract: [This document addresses Mobility Issues and Their Solutions for Mesh Networks.]
Purpose: [Final Proposal for the IEEE Standard]
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
Ho-In Jeon, (Kyung-Won University), Yongsik Shin (SKTelecom)

2. Mobility Issues and Their Solutions for Mesh Networks
January 2006
Mobility Issues and Their Solutions for Mesh Networks
Ho-In Jeon, Yong-Bae Kim, and Bum-Joo Kim
Kyung-Won University, HNRC of IITA, Republic of Korea
Yongsik Shin
SKTelecom, Republic of Korea
Ho-In Jeon, (Kyung-Won University), Yongsik Shin (SKTelecom)

3. doc.: IEEE 802.15-<doc#>
<month year>
doc.: IEEE <doc#>
January 2006
Contents
Introduction
Issues of Mesh Networks
A Scenario for the operation of Mesh Network
Mobility Support of Mesh Networks
Node Mobility
Whole PAN Mobility
Solutions for the Mobility Issues
Features of the proposed Scheme
Conclusion
Ho-In Jeon, (Kyung-Won University), Yongsik Shin (SKTelecom)
<author>, <company>

4. Issues of Mesh Networks
<month year>
doc.: IEEE <doc#>
January 2006
Issues of Mesh Networks
Beacon Scheduling for Collision Avoidance
Short Address Allocation Algorithms
Routing Algorithm: Proactive or Reactive
Power-Efficient Operational Mode
QoS Support
Adoption of RTS/CTS for Data Transmission
Mobility Support for Mesh Devices and Mesh PANs
Ho-In Jeon, (Kyung-Won University), Yongsik Shin (SKTelecom)
<author>, <company>

5. U-Home with Mesh Network
January 2006
U-Home with Mesh Network
Utility Room
Washer
Gas
Meter PC
Mesh
Mesh
Room #3
VPhone
Gas
Oven
PDA
DTV
Room #2
Bath-
room
Refrig.
DTV PC
Microwave
Oven
Oven
Kitchen
STB
DCam.
: IEEE1394 or UWB Connectivity
: IEEE802.11x, 15.3, ZigBee/15.4, 15.5 Mesh
Mesh
Mesh
VPhone
Living Room
Door
Phone
DTV
ZigBee/15.4
802.11a/g/n/e,
IEEE
Mesh PNC
Meter
Reader
PVR
Room #1 PC
Power
Meter
DCam.
Room #4
DTV
VDSL MODEM
DAM
PDA
Water
Meter
PVR
Phone
Jack
HS/ MMRG
Printer
Phone
Jack
AP or PNC
PDA
DCam.
Cable, Satellite, Terrestrial
FTTH
DSLAM
ONU
Internet
Ho-In Jeon, (Kyung-Won University), Yongsik Shin (SKTelecom)

6. Why Mobility Issues for Mesh Networks
<month year>
doc.: IEEE <doc#>
January 2006
Why Mobility Issues for Mesh Networks
Users carry mesh nodes that are capable of being PNC.
PNC as well as mesh nodes transmits beacons
The PNC can have more than one mesh device that have been associated with it, forming a mesh PAN
When he returns back to his house, the U-terminal is assumed to behave like a universal remote controller.
The whole PAN is moving causing some problems.
Here are some scenarios for the mobility support
Most important services for the U-Home services.
Ho-In Jeon, (Kyung-Won University), Yongsik Shin (SKTelecom)
<author>, <company>

7. A Scenario for Mesh Network Operations
January 2006
A Scenario for Mesh Network Operations 4 9 1 2 6 5 2 9 1 6
PNC 3 4 8 7
Issues to be resolved
Association and Reassociation Procedure
Beacon Scheduling
Short Address Allocations
Creation and Update of Neighborhood Table
Ho-In Jeon, (Kyung-Won University), Yongsik Shin (SKTelecom)

8. PNC Formation of the Mesh
January 2006
PNC Formation of the Mesh 1 1
PNC
Device 1 first scans passively first and actively next.
When it finds that there is no device that he can associate with, it becomes the PNC.
Once a device becomes a PNC, it starts to transmit its beacon at the beginning of the superframe.
Ho-In Jeon, (Kyung-Won University), Yongsik Shin (SKTelecom)

9. Joining of Device 2 to the Mesh
January 2006
Joining of Device 2 to the Mesh 1 2 2 1
PNC
Dev. 2 hears the beacon form PNC and gets associated with it.
When associated, it gets PANID, Short Address, and other sets of information from PNC and determines when to send its beacon.
Dev. 1 and 2 listen to beacons of each other and store information about their neighbor in the Neighborhood Table.
Ho-In Jeon, (Kyung-Won University), Yongsik Shin (SKTelecom)

10. Association Relations and Beacon Tx
January 2006
Association Relations and Beacon Tx
Solid blue line represents the Parent-Child relations based on associations.
Red line represents directly reachable.
Every mesh device except leaf nodes transmits beacon during the BOP (Beacon-Only Period) to save BOP usage.
Beacon scheduling has been applied. 2 1
PNC 3
Superframe
Active Period
Inactive Period
BOP
CAP 1 2 3
Ho-In Jeon, (Kyung-Won University), Yongsik Shin (SKTelecom)

11. Association and Direct Links Relations
January 2006
Association and Direct Links Relations 4 9 1 2 6 5 2 9 1 6
PNC 3 4 8 7
BOP
CAP 1 2 3 4 5 6 8 7 9
Ho-In Jeon, (Kyung-Won University), Yongsik Shin (SKTelecom)

12. Association and Direct Links Relations
January 2006
Association and Direct Links Relations 2 5 9 1
PNC 6 8 4 3 7
Blue Line: Association Relations
Red Line: Direct Communication Capable
Association Policy
New nodes are associated with the nodes which are as close to the PNC and possible
If RSSI is not high enough for reliable communications, then it can choose other node as its parent.
Ho-In Jeon, (Kyung-Won University), Yongsik Shin (SKTelecom)

13. Differences from Current Baseline
January 2006
Differences from Current Baseline
The Baseline Document for HR mesh does not perform association process, and thus no PNC concept.
A new device does not know when the superframe has started.
There is no information whether a new device may send his beacon prior to the first beacon transmission time.
No common PAN_ID guaranteed.
The proposed mesh network starts from PNC having parent-child relations and direct communication links.
The superframe structure is determined by the PNC.
Every node knows exactly when the superframe started.
Consistent PAN-ID
Ho-In Jeon, (Kyung-Won University), Yongsik Shin (SKTelecom)

14. The Mobility Scenarios
January 2006
The Mobility Scenarios
Only one non-PNC device is moving
A Coordinator having its children is moving
The whole PAN is moving and joining the other WPAN
PNC to PNC Connection
PNC to Coordinator Connection
Coordinator to Coordinator Connection
Coordinator to End Device Connection
End Device to End Device Connection
Ho-In Jeon, (Kyung-Won University), Yongsik Shin (SKTelecom)

15. One non-PNC Device is Moving
January 2006
Issues
Fast Reassociation needed
Short address assigned can be retained
PNC
coordinator
device
Ho-In Jeon, (Kyung-Won University), Yongsik Shin (SKTelecom)

16. The Coordinator is Moving
January 2006
The Coordinator is Moving
Issues
Beacon Conflicts
Beacon rescheduling
Orphan node treatment
PNC
coordinator
device
Ho-In Jeon, (Kyung-Won University), Yongsik Shin (SKTelecom)

17. The problem when the Coordinator is moving
January 2006
The problem when the Coordinator is moving
Node 7
Node 2
Node 1
Orphan
: Beacon
: CAP
PNC
Node 1
Node 7
Node 2
Beacon Conflict due to the movement of the Coordinator
Ho-In Jeon, (Kyung-Won University), Yongsik Shin (SKTelecom)

18. PNC to PNC Connection PAN_1 PAN_2 I2 J2 G2 D2 A2 C2 H2 B2 F2 E2 E1 B1
January 2006
PNC to PNC Connection
Coordinator
PNC2
End Device
PAN_2 I2 J2 G2 D2 A2 C2 H2 B2 F2 E2 E1
End Device B1
Coordinator F1
PNC G1 C1 A1 J1
End Device H1 D1
PAN_1 I1
Ho-In Jeon, (Kyung-Won University), Yongsik Shin (SKTelecom)

19. PNC to Coordinator Connection
January 2006
PNC to Coordinator Connection E1
End Device
PNC2 B1
Coordinator
End Device
Coordinator B2 E2 F2 I2 J2 K2 H2 D2 C2 A2 F1
PNC G1 C1 A1 J1
End Device H1 D1 I1
PAN_1
PAN_2
Ho-In Jeon, (Kyung-Won University), Yongsik Shin (SKTelecom)

20. POS PAN_1 PAN_2 Coordinator to Coordinator Connection A2 C2 H2 I2 J2
January 2006
Coordinator to Coordinator Connection
PNC
POS
PNC
Coordinator
End Device A2 C2 H2 I2 J2 E2 F2 K2 D2 B2 A1
Coordinator B1 C1 D1 K1 H1 E1 F1
End Device
Coordinator
End Device J1
PAN_1
PAN_2
Ho-In Jeon, (Kyung-Won University), Yongsik Shin (SKTelecom)

21. Coordinator to Device Connection
January 2006
Coordinator to Device Connection
PNC
Coordinator
End Device E2 B2 A2 C2 K2 F2 H2 I2 D2 J2
POS
PNC A1
Coordinator B1 C1 D1 E1 F1 K1 H1
End Device
Coordinator
End Device
PAN_2
PAN_1 J1
Ho-In Jeon, (Kyung-Won University), Yongsik Shin (SKTelecom)

22. Device to Device Connection
January 2006
Device to Device Connection
PNC
Coordinator
End Device A2 E2 B2 C2 D2 H2 I2 J2 F2 K2
PNC A1
Coordinator B1 C1 D1 E1 I1 F1 K1 H1
End Device
Coordinator
End Device
POS J1
PAN_2
PAN_1
Ho-In Jeon, (Kyung-Won University), Yongsik Shin (SKTelecom)

23. Mobility Issues Revisited
January 2006
Mobility Issues Revisited
Mobile_PAN
Moving
Fixed_PAN
PNC
device
Assumptions of Mobile_PAN : Every device that belongs to Mobile PAN moves together in the most practical case
PNC
Coordinator
Device
Ho-In Jeon, (Kyung-Won University), Yongsik Shin (SKTelecom)

24. Cases for Device Mobility
January 2006
Cases for Device Mobility
When the two PANs are using same channel
Mobile PAN and Fiexed PAN causes beacon conflict
Data conflict due to the beacon conflict
The Beacon Rescheduling is needed.
The two PANs naturally merge.
When the two PANs are using different channels
They behave like the other WPAN does not even exist.
Some scanning mechanism is needed for the combination of the two WPANs
Ho-In Jeon, (Kyung-Won University), Yongsik Shin (SKTelecom)

25. Different Channel Cases
January 2006
Different Channel Cases
Estimated time required to merge two PANs that are using two different channels
There are 16 Channels for 2.4GHz band
Scan-Duration for 1 channel = aBaseSuperframeDuration x (2n+1)  ; n = 0~14
minScanDuration = 960 x 2 = 1920 [Symbols] = [msec]
maxScanDuration = 960 x (214+1) = [Symbols] = 2, [sec]
It takes 11 hours maximum for scanning 16 channels
Ho-In Jeon, (Kyung-Won University), Yongsik Shin (SKTelecom)

26. New Search Command for Solutions
January 2006
New Search Command for Solutions
Command Frame
Identifier
Command Name
0x01
Association request
0x02
Association response
0x03
Disassociation notification
0x04
Data request
0x05
PAN ID conflict notification
0x06
Orphan notification
0x07
Beacon request
0x08
Coordinator realignment
0x09
GTS request
0x0a
SearchNewPan request
0x0b
SearchNewPan response
0x0c-oxff
Reserved
Name
Description
ScanType
0x00 = energy detection scan
0x01 = active scan
0x02 = passive scan
0x03 = orphan scan
0x04 = search other PAN
Ho-In Jeon, (Kyung-Won University), Yongsik Shin (SKTelecom)

27. Timing Charts for Searching PAN
January 2006
Timing Charts for Searching PAN
Mobile PAN Higher Layer
Mobile PAN MAC
Fixed PAN MAC
MLME-SCAN.request
SearchNewPAN command
Acknowledgement
Scan Duration
SearchNewPAN response
Acknowledgement
MLME-BEACON- NOTIFY.indication
MLME-SCAN.confirm
Ho-In Jeon, (Kyung-Won University), Yongsik Shin (SKTelecom)

28. Solutions by Using Beacon Payload
January 2006
Solutions by Using Beacon Payload
Name
Type
Value
Search_superframe
boolean
True or False
SearchPanDuration
integer
0x0e
NewPanExist
NewPanChannel
bitmap
32bit
NewPanId
0xffff
Ho-In Jeon, (Kyung-Won University), Yongsik Shin (SKTelecom)

29. Conclusions The PNC formation follows the way similar to IEEE 802.15.4
January 2006
Conclusions
The PNC formation follows the way similar to IEEE
Most applications require mobility of mesh nodes.
Beacon scheduling is assumed to be done.
Mobility causes some problems.
Some scenarios have been identified, and some solutions are presented using new Search Command.
More efforts will be made and presented in the near future.
Ho-In Jeon, (Kyung-Won University), Yongsik Shin (SKTelecom)

30. Acknowledgment This work has been supported partly by HNRC of IITA.
January 2006
Acknowledgment
This work has been supported partly by HNRC of IITA.
Ho-In Jeon, (Kyung-Won University), Yongsik Shin (SKTelecom)