320 likes | 444 Views
Project: IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANs) Submission Title: [Mobility Issues and Their Solutions for Mesh Networks ] Date Submitted: [19 January , 200 6] Source: [Ho-In Jeon (1), Yong-Bae Kim (2), Bum-Joo Kim (2), Yongsik Shin (3)]
E N D
Project: IEEE P802.15 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:[ +82-31-753-2533], Voice 2:[ +82-19-9101-1394] FAX: [+82-31-753-2532], E-Mail:[jeon1394@kornet.net] 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 IEEE802.15.5 Standard] 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. Ho-In Jeon, (Kyung-Won University), Yongsik Shin (SKTelecom)
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)
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)
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 Issues of Mesh Networks Ho-In Jeon, (Kyung-Won University), Yongsik Shin (SKTelecom)
Mesh Mesh PC U-Home with Mesh Network Gas Meter Washer UtilityRoom Room #3 Mesh Mesh VPhone Gas Oven PDA Room #2 Bath- room DTV Refrig. DTV PC Microwave Oven Oven Kitchen STB DCam. : IEEE1394 or UWB Connectivity : IEEE802.11x, 15.3, ZigBee/15.4, 15.5 Mesh Door Phone Living Room VPhone ZigBee/15.4 802.11a/g/n/e, IEEE802.15.3 MeshPNC DTV Meter Reader PVR Room #1 Power Meter PC DCam. Room #4 DTV VDSLMODEM PDA DAM Water Meter PVR Printer Phone Jack HS/MMRG Phone Jack AP or PNC PDA DCam. Cable, Satellite, Terrestrial Internet FTTH DSLAM ONU Ho-In Jeon, (Kyung-Won University), Yongsik Shin (SKTelecom)
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 hishouse, 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. Why Mobility Issues for Mesh Networks Ho-In Jeon, (Kyung-Won University), Yongsik Shin (SKTelecom)
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 andReassociation Procedure • Beacon Scheduling • Short Address Allocations • Creation and Update ofNeighborhood Table Ho-In Jeon, (Kyung-Won University), Yongsik Shin (SKTelecom)
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)
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)
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 CAP BOP 1 2 3 Ho-In Jeon, (Kyung-Won University), Yongsik Shin (SKTelecom)
Association and Direct Links Relations 4 9 1 2 6 5 2 9 1 6 PNC 3 4 8 7 CAP BOP 1 3 4 5 6 2 8 7 9 Ho-In Jeon, (Kyung-Won University), Yongsik Shin (SKTelecom)
Association and Direct Links Relations 2 5 9 1 6 PNC 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 RSSIis not high enough for reliable communications, then it can choose other node as its parent. Ho-In Jeon, (Kyung-Won University), Yongsik Shin (SKTelecom)
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)
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)
One non-PNC Device is Moving • Issues • Fast Reassociation needed • Short address assigned can be retained device coordinator PNC Ho-In Jeon, (Kyung-Won University), Yongsik Shin (SKTelecom)
The Coordinator is Moving • Issues • Beacon Conflicts • Beacon rescheduling • Orphan node treatment device coordinator PNC Ho-In Jeon, (Kyung-Won University), Yongsik Shin (SKTelecom)
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)
I2 D2 H2 J2 G2 A2 C2 PNC2 Coordinator End Device F2 B2 E2 End Device PAN_2 PNC to PNC Connection E1 End Device B1 Coordinator F1 PNC A1 G1 C1 J1 End Device H1 D1 PAN_1 I1 Ho-In Jeon, (Kyung-Won University), Yongsik Shin (SKTelecom)
A2 D2 C2 B2 Coordinator I2 H2 K2 F2 E2 Coordinator End Device J2 End Device PNC to Coordinator Connection E1 End Device PNC2 B1 Coordinator F1 PNC A1 G1 C1 J1 End Device H1 D1 I1 PAN_1 PAN_2 Ho-In Jeon, (Kyung-Won University), Yongsik Shin (SKTelecom)
PNC A2 B2 Coordinator D2 C2 I2 H2 K2 F2 E2 End Device End Device J2 Coordinator to Coordinator Connection PNC POS A1 Coordinator D1 C1 B1 H1 K1 E1 F1 Coordinator End Device End Device J1 PAN_1 PAN_2 Ho-In Jeon, (Kyung-Won University), Yongsik Shin (SKTelecom)
A2 Coordinator B2 D2 C2 I2 H2 K2 E2 F2 Coordinator End Device End Device J2 Coordinator to Device Connection PNC POS PNC A1 Coordinator D1 C1 B1 K1 E1 H1 F1 Coordinator End Device End Device PAN_2 PAN_1 J1 Ho-In Jeon, (Kyung-Won University), Yongsik Shin (SKTelecom)
PNC A2 Coordinator D2 C2 B2 I2 H2 K2 E2 F2 Coordinator End Device End Device J2 Device to Device Connection PNC A1 Coordinator D1 C1 B1 I1 H1 K1 E1 F1 Coordinator End Device End Device POS J1 PAN_2 PAN_1 Ho-In Jeon, (Kyung-Won University), Yongsik Shin (SKTelecom)
Mobility Issues Revisited Mobile_PAN Moving Fixed_PAN device PNC • 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)
Mobile PAN Colocated in the Fixed PAN Fixed_PAN Mobile_PAN PNC device PNC Coordinator Device Ho-In Jeon, (Kyung-Won University), Yongsik Shin (SKTelecom)
Rearrange of the Parameters Fixed_PAN PNC Coordinator Device Ho-In Jeon, (Kyung-Won University), Yongsik Shin (SKTelecom)
Cases for Device Mobility • When the two PANs are using same channel • Mobile PAN andFiexed 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)
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] = 30.72 [msec] • maxScanDuration = 960 x (214+1) = 15729600 [Symbols] = 2,516.73 [sec] • It takes 11 hours maximum for scanning 16 channels Ho-In Jeon, (Kyung-Won University), Yongsik Shin (SKTelecom)
New Search Command for Solutions Ho-In Jeon, (Kyung-Won University), Yongsik Shin (SKTelecom)
Timing Charts for Searching PAN Mobile PANMAC Mobile PANHigher Layer Fixed PANMAC 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)
Solutions by Using Beacon Payload Ho-In Jeon, (Kyung-Won University), Yongsik Shin (SKTelecom)
Conclusions • The PNC formation follows the way similar to IEEE 802.15.4 • 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)
Acknowledgment • This work has been supported partly by TTA and SKTelecom. Ho-In Jeon, (Kyung-Won University), Yongsik Shin (SKTelecom)