1. doc.: IEEE 802.15-07-0794-00-WNG0 Submission July 2007 Jin-Seok Bae (KATS), Jaehwang Yu (SKT), and Ho-In Jeon (KWU) Slide 1 Project: IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANs) Submission Title: [ Enhancement of IEEE 802.15.4 MAC for QoS and Mobility Support in Beacon- Enabled Mesh Networks ] Date Submitted: [18 July, 2007] Source: [Jin-Seok Bae (1), Woo-Jin Shim, Yong-Gil Park, Jaehwang Yu (2), and Ho-In Jeon (3)] Company: [Korean Agency for Technology and Standards (KATS) (1), SKTelecom (2), and Dept. Electronic Engineering, Kyung-Won University (KWU) (2)] Address: [San 65, Bok-Jung-Dong, Sung-Nam-Shi, Kyung-Gi-Do, Republic of Korea] Voice 1: [ +82-31-753-2533], Voice 2:[ +82-10-4708-5328] FAX: [+82-31-753-2532], E-Mail: [jeon1394@kornet.net] Re: [This work has been supported by KATS and SKTelecom.] Abstract:[This document proposes an enhancement of IEEE 802.15.4 MAC that can support QoS and mobility of nodes not only in the star but also in the Mesh Network by using different Access Category and corresponding backoff times for the channel access. If the network is running in the beacon mode, we can allocate a dedicated time slot for the PQP (Prioritized QoS Period) for the specific QoS implementations.] Purpose:[Technical Contributions on the IEEE 802.15 WNG Task Group] 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.

2. doc.: IEEE 802.15-07-0794-00-WNG0 Submission July 2007 Jin-Seok Bae (KATS), Jaehwang Yu (SKT), and Ho-In Jeon (KWU) Slide 2 Enhancement of IEEE 802.15.4 MAC for QoS and Mobility Support in Beacon-Enabled Wireless Mesh Networks Jin-Seok Bae (1), Woo-Jin Shim, Yong-Gil Park, Jaehwang Yu (2), and Ho-In Jeon (3) (1) KATS (Korea Agency for Technology and Standards) (2) SKTelecom, (3) Kyung-Won University Republic of Korea

3. doc.: IEEE 802.15-07-0794-00-WNG0 Submission July 2007 Jin-Seok Bae (KATS), Jaehwang Yu (SKT), and Ho-In Jeon (KWU) Slide 3 Contents Introduction Some Scenarios Requiring Mesh Mobility and QoS A Proposal on the Enhancement of IEEE 802.15.4 for the support of beacon-enabled synchronized Mesh Network with QoS and Mobility MAC Enhancement Synchronized TDMA with Beacon –BOP, PQP, CAP with AC, CFP, and DSP –Beacon Scheduling –Addressing for mobility Conclusion

4. doc.: IEEE 802.15-07-0794-00-WNG0 Submission July 2007 Jin-Seok Bae (KATS), Jaehwang Yu (SKT), and Ho-In Jeon (KWU) Slide 4 Introduction The primary performance metrics of IEEE 802.15.4 LR-WPAN are cost and power consumption. For the sake of reducing implementation complexity, IEEE 802. 15.4 supports CFP as an optional feature for star network only. When IEEE 802.15.4 is applied to implement mesh network, there is no way that CFP can be implemented because of lack of overall network synchronization. One of possible remedies for this limitation is to adopt new superframe structure having BOP with beacons scheduled. This concept of BOP will provide a perfect synchronization for all the mesh network nodes within one superframe. Then we can introduce TDMA-based channel access with QoS and mobility support.

5. doc.: IEEE 802.15-07-0794-00-WNG0 Submission July 2007 Jin-Seok Bae (KATS), Jaehwang Yu (SKT), and Ho-In Jeon (KWU) Slide 5 Services Requiring Mesh Mobility and QoS U-Home Services U-Healthcare U-Parking Lot U-Subway Station Management U-Underground Facility Management And there are a lot more!

6. doc.: IEEE 802.15-07-0794-00-WNG0 Submission July 2007 Jin-Seok Bae (KATS), Jaehwang Yu (SKT), and Ho-In Jeon (KWU) Slide 6 U-Home Requiring Mesh Mobility and QoS DCam. PVR VPhone DTV DAM HS/ MMRG Internet FTTH DTV PVR VPhone Refrig. DCam. PC DTV STB PDA Living Room Room #1 Room #3 Room #2 Kitchen Door Phone Water Meter Gas Meter WiBEEM Oven Cable, Satellite, Terrestrial PC AP or PNC : WiBEEM PDA DCam. Printer PC PDA Room #4 DTV Power Meter Reader Phone Jack Gas Oven Microwave Oven DSLAM Phone Jack Bath- room Utility Room WiBEEM MPC ONU VDSL MODEM : IEEE1394 Washer WiBEEM Association Point

7. doc.: IEEE 802.15-07-0794-00-WNG0 Submission July 2007 Jin-Seok Bae (KATS), Jaehwang Yu (SKT), and Ho-In Jeon (KWU) Slide 7 Home Network services requiring mesh but not QoS –AMR –Home Appliance Control –Light Switch Control –Home Viewer Service Home Network services requiring mesh and QoS –Gas Valve Shutdown –u-Healthcare Service u-Home Service with u-Healthcare

8. doc.: IEEE 802.15-07-0794-00-WNG0 Submission July 2007 Jin-Seok Bae (KATS), Jaehwang Yu (SKT), and Ho-In Jeon (KWU) Slide 8 Access Mechanism of IEEE 802.15.4 The superframe is managed by the PAN coordinator and is bounded by beacon messages sent by the PAN coordinator Each beacon contains information about synchronization Network devices that heard the PNC must attempt to do it between two successive beacons If any node cannot hear the beacon of PNC, while it can talk to his neighbors (mesh network), there is no way that they are synchronized with the beacons transmitted by the PNC, and thus it operates in the non-beacon mode.

9. doc.: IEEE 802.15-07-0794-00-WNG0 Submission July 2007 Jin-Seok Bae (KATS), Jaehwang Yu (SKT), and Ho-In Jeon (KWU) Slide 9 Parameterized QoS in IEEE 802.15.4 The PAN coordinator can assign dedicated portions of the superframe to a specific network device requesting it –These segments of time are called GTSs –This is considered to be parameterized QoS –Only star topology can support this QoS When mesh network is implemented, any node that cannot hear the beacon of the PNC cannot synchronize. 1514131211109876543210 GTS #1 GTS #2 Beacon CAP CFP Inactive Beacon 210

10. doc.: IEEE 802.15-07-0794-00-WNG0 Submission July 2007 Jin-Seok Bae (KATS), Jaehwang Yu (SKT), and Ho-In Jeon (KWU) Slide 10 Mesh Network based on IEEE 802.15.4 Mesh network based on the IEEE 802.15.4 –It cannot operate in the beacon mode due to beacon conflicts. –Prioritized QoS can be implemented by applying different backoff times for different traffic of different AC at the CAP. –No Parameterized QoS can be supported. –DRP (Distributed Reservation Protocol) may not be adopted because there is no synchronization mechanism. Possible Remedies –Allow a new mechanism that can provide synchronization over beacons. –Adopt a new time slot such as PQP (Prioritized QoS Period) based on the User Priority.

11. doc.: IEEE 802.15-07-0794-00-WNG0 Submission July 2007 Jin-Seok Bae (KATS), Jaehwang Yu (SKT), and Ho-In Jeon (KWU) Slide 11 Possible QoS with Enhanced 802.15.4 MAC Parameterized QoS –The parameterized QoS requires short total end-to-end over- the-air delays for voice and/or multimedia traffic –Delay-sensitive traffic requires parameterized QoS implemented in GTS in the beacon mode. –The non-beacon mode network cannot provide this. Prioritized QoS –May adopt User Priority or AC (Access Category) to allow relevant waiting time. –Different backoff time for different access category during he CAP: This mechanism can be done in non-beacon mode. –Introduction of totally new period for PQP (Prioritized QoS Period): This approach requires beacon mode.

12. doc.: IEEE 802.15-07-0794-00-WNG0 Submission July 2007 Jin-Seok Bae (KATS), Jaehwang Yu (SKT), and Ho-In Jeon (KWU) Slide 12 New Superframe Structure for QoS BOP CAPCFP DSP Beacon #1 SD (Superframe Duration) BI (Beacon Interval) BOPL BOPL = BTTSL × maxBeaconNumber [symbols] SD = aBaseSuperframeDuration × 2 SO [symbols] = 960 × 2 SO [symbols] BI = aBaseSuperframeDuration × 2 BO [symbols] = 960 × 2 BO [symbols] Beacon #1 Beacon #2 Beacon #n PQP PQP = PQPL × aBaseSuperframeDuration [symbols] CFP = CFPL × aBaseSuperframeDuration [symbols] CFP

13. doc.: IEEE 802.15-07-0794-00-WNG0 Submission July 2007 Jin-Seok Bae (KATS), Jaehwang Yu (SKT), and Ho-In Jeon (KWU) Slide 13 39 38 37 21 22 23 24 25 26 27 28 29 30 31 32 33 35 36 34 20 19 18 1 2 3 4 5 6 7 8 9 MPC 10 11 12 13 14 16 17 15 40 1 2 3 4 5 6 7 8 9 10 13 11 6 12 9 9 14 11 8 10 11 15 5 12 5 16 11 6 9 13 7 7 8 7 12 10 15 14 Beacon Scheduling Done for 40 Nodes CFP PQP Deep Sleep BOP 1 2 34 5 6 78 9 10 12 1113 14 1516 1 2 3456 7 10 11 8 9 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 3031 32 3334 35 36 37 38 39 40 BTTSL BTTS CAP

14. doc.: IEEE 802.15-07-0794-00-WNG0 Submission July 2007 Jin-Seok Bae (KATS), Jaehwang Yu (SKT), and Ho-In Jeon (KWU) Slide 14 Beacon Frame Format and Payload for QoS

15. doc.: IEEE 802.15-07-0794-00-WNG0 Submission July 2007 Jin-Seok Bae (KATS), Jaehwang Yu (SKT), and Ho-In Jeon (KWU) Slide 15 MAC and NWK FC Fields for QoS Bits : 0-234567-910-1112-1314-15 Frame Type Security Enabled Frame Pending Ack. Request Intra- PAN Reserved Destination Addressing Mode QoS Priority Source Addressing Mode Bits : 0-1 Frame type 2-5 Protocol version 6 Discover route 7 Fragmentation 9 Security 12-15 Reserved 8 Multicast Flag MAC Frame Control Field NWK Frame Control Field 10-11 QoS Priority

16. doc.: IEEE 802.15-07-0794-00-WNG0 Submission July 2007 Jin-Seok Bae (KATS), Jaehwang Yu (SKT), and Ho-In Jeon (KWU) Slide 16 Proposed Prioritized Channel Access in CAP Each channel access function contends with –AIFS[AC] (instead of LIFS) and CW[AC] (instead of CW) Busy Medium SIFS AIFS[AC] Backoff Window Slot Time Defer Access Select Slot and decrement backoff as long as medium stays idle AIFS[AC] Contention Window from [0,CW[AC]] Immediate access when medium is idle >= AIFS[AC] Next Frame

17. doc.: IEEE 802.15-07-0794-00-WNG0 Submission July 2007 Jin-Seok Bae (KATS), Jaehwang Yu (SKT), and Ho-In Jeon (KWU) Slide 17 Backoff Times with UP for New MAC PriorityAccess CategoryDesignated Backoff Time at the CAP Lowest Highest 026 – 35 126 – 30 2 11 – 25 3 11 – 20 4 11 – 15 5 0 – 10 6 0 – 7 7 0 – 5 BOP CAPCFP DSP Beacon #1 Beacon #2 Traffic with UP of 6 and 7 only can access the channel in this tile slot. PQP

18. doc.: IEEE 802.15-07-0794-00-WNG0 Submission July 2007 Jin-Seok Bae (KATS), Jaehwang Yu (SKT), and Ho-In Jeon (KWU) Slide 18 Conclusions Introduced the needs for mobility and QoS based on IEEE 802.15.4. Suggested new superframe structure that can support Mobility and QoS for Mesh Network –Parameterized QoS with –Prioritized QoS –High Speed Mobility with fast update of beacon information Enhancement of IEEE 802.15.4 MAC based on BOP and PQP provides QoS mechanism for prioritized QoS. It is backward compatible to legacy IEEE 802.15.4. The overall mesh network system is working with TDMA-based accurate allocation of time period.

19. doc.: IEEE 802.15-07-0794-00-WNG0 Submission July 2007 Jin-Seok Bae (KATS), Jaehwang Yu (SKT), and Ho-In Jeon (KWU) Slide 19 Acknowledgment This work has been supported by KATS and SKTelecom.