1. doc.: IEEE 802.15-0503r0 Submission July 2008 L. Winkel, M. Bahr, Siemens AGSlide 1 Project: IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANs) Submission Title: [ Preliminary Proposal for Factory Automation ] Date Submitted: [ 15 July, 2008 ] Source: [ Ludwig Winkel, Michael Bahr ] Company [ Siemens AG ] Address [Siemensallee 74, Karlsruhe, Germany] Voice:[+49-721-595 6098], FAX: [+49-721-595 893 6098], E-Mail:[ludwig.winkel@siemens.com] Re: [response to Call for Preliminary Proposals doc 15-08/0373r1] Abstract:[Preliminary proposal to IEEE 802.15.4e for wireless sensor/actuator networks applicable for factory automation.] Purpose:[amending 802.15.4-2006 for matching the requirements for factory automation] 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 802.15-0503r0 Submission July 2008 L. Winkel, M. Bahr, Siemens AGSlide 2 Preliminary Proposal for Factory Automation Ludwig Winkel (Siemens AG) Michael Bahr (Siemens AG)

3. doc.: IEEE 802.15-0503r0 Submission July 2008 L. Winkel, M. Bahr, Siemens AGSlide 3 Overview Support of factory automation and process automation Proposal for Factory Automation –Motivation –Proposed MAC solution Considerations for Process Automation –Mesh Support

4. doc.: IEEE 802.15-0503r0 Submission July 2008 L. Winkel, M. Bahr, Siemens AGSlide 4 Support of Process Automation and Factory Automation process automation (PA) and factory automation (FA) are related but quite inde- pendent use cases with different requirements use of same wireless communication technology (IEEE 802.15.4) is beneficial configurability of IEEE 802.15.4e –common base functionality –configurable for process automation use cases –configurable for factory automation use cases

5. doc.: IEEE 802.15-0503r0 Submission July 2008 L. Winkel, M. Bahr, Siemens AGSlide 5 MAC Proposal for Factory Automation

6. doc.: IEEE 802.15-0503r0 Submission July 2008 L. Winkel, M. Bahr, Siemens AGSlide 6 Use Cases of Factory Automation automotive – robots – suspension tracks – portable machine tools –milling, turning –robot revolver filling cargo – airport logistics – post packaging industry special engineering conveyor technique

7. doc.: IEEE 802.15-0503r0 Submission July 2008 L. Winkel, M. Bahr, Siemens AGSlide 7 Requirements and Assumptions high determinism high reliability low latency: –transmission of sensor data in  10 ms –low round-trip time many sensors per gateway –might be more than 100 sensors per gateway assume controlled envi- ronment (factory floor) configuration for optimal performance network management and frequency planning for avoidance of co- existence issues

8. doc.: IEEE 802.15-0503r0 Submission July 2008 L. Winkel, M. Bahr, Siemens AGSlide 8 Why IEEE 802.15.4? coexistence with IEEE 802.11 WLAN –3 non-overlapping channels for IEEE 802.11 –4 channels for IEEE 802.15.4 sufficient range worldwide acceptance worldwide standard North America (similar worldwide)

9. doc.: IEEE 802.15-0503r0 Submission July 2008 L. Winkel, M. Bahr, Siemens AGSlide 9 Network Topology star topology gateway devices –sensors: unidirectional data exchange from devices to gateway –actuators: bidirectional data exchange between devices and gateway

10. doc.: IEEE 802.15-0503r0 Submission July 2008 L. Winkel, M. Bahr, Siemens AGSlide 10 General Concept IEEE 802.15.4 PHY frames Time Division Multiple Access –Superframe with timeslots of fixed length –shared group timeslots with CSMA –addressing based on timeslot location or short address –modified MAC frame no channel hopping

11. doc.: IEEE 802.15-0503r0 Submission July 2008 L. Winkel, M. Bahr, Siemens AGSlide 11 PHY Frame Format IEEE 802.15.4 PHY frame format different preamble values –differentiate IEEE 802.15.4e FA devices from other IEEE 802.15.4 devices

12. doc.: IEEE 802.15-0503r0 Submission July 2008 L. Winkel, M. Bahr, Siemens AGSlide 12 Time Division Multiple Access Superframe –starts with beacon –followed by n timeslots of equal, fixed length Timeslots –one device per timeslot (dedicated timeslot) –determinism (re-)synchronization through beacon –allows sleep mode / power save of devices time slot time

13. doc.: IEEE 802.15-0503r0 Submission July 2008 L. Winkel, M. Bahr, Siemens AGSlide 13 Shared Group Timeslots more than one device per timeslot carrier sense multiple access within shared group timeslot 1 or more continous timeslots concatenated to a shared group timeslot all timeslots in single shared group timeslot  network with carrier sense multiple access mixture between fixed, deterministic timeslots and shared group timeslots possible time slot time

14. doc.: IEEE 802.15-0503r0 Submission July 2008 L. Winkel, M. Bahr, Siemens AGSlide 14 Structure of Superframe existence of management timeslots configurable during setup number of (timeslots for) sensors and actuators configurable during setup sensors time actuators

15. doc.: IEEE 802.15-0503r0 Submission July 2008 L. Winkel, M. Bahr, Siemens AGSlide 15 MAC Frame Format implicit addressing through slot number –omits MAC header fields very short PSDU increases efficiency dramatically –turnaround time / latency main criteria –every bit counts: data payload is very short assume 2 byte data payload 3 more bytes mean a 30% increase in latency! FCS for error recognition

16. doc.: IEEE 802.15-0503r0 Submission July 2008 L. Winkel, M. Bahr, Siemens AGSlide 16 Transmission Modes 3 transmission modes –Discovery –Configuration –Online transmission mode is signalled in beacon

17. doc.: IEEE 802.15-0503r0 Submission July 2008 L. Winkel, M. Bahr, Siemens AGSlide 17 Discovery Mode first step in network setup (addition of new devices) device sends its current configuration to gateway till ACK

18. doc.: IEEE 802.15-0503r0 Submission July 2008 L. Winkel, M. Bahr, Siemens AGSlide 18 Configuration Mode second step in network setup used for re-configuration of network gateway sends new configuration to device

19. doc.: IEEE 802.15-0503r0 Submission July 2008 L. Winkel, M. Bahr, Siemens AGSlide 19 Configurable Parameters structure of superframe (management timeslots, sensor timeslots, actuator timeslots) number of timeslots duration of timeslots shared group timeslots transmission channel

20. doc.: IEEE 802.15-0503r0 Submission July 2008 L. Winkel, M. Bahr, Siemens AGSlide 20 Online Mode transmission of the actual data for factory automation (productivity data) gateway acknowledges receipt of data from sensors in beacon gateway signals direction of transmission for actuator timeslots in beacon –transmission with or without acknowledgement or with block acknowledgement

21. doc.: IEEE 802.15-0503r0 Submission July 2008 L. Winkel, M. Bahr, Siemens AGSlide 21 Use of Single Channel avoids „unproductive“ channel switch times allows addressing by timeslot better support of roaming (e.g. conveyor belts) very good coexistence with other wireless networks (e.g. WLAN on different channels)

22. doc.: IEEE 802.15-0503r0 Submission July 2008 L. Winkel, M. Bahr, Siemens AGSlide 22 Considerations on Process Automation see also 15-08/409r2

23. doc.: IEEE 802.15-0503r0 Submission July 2008 L. Winkel, M. Bahr, Siemens AGSlide 23 Mesh Support applicable for process automation IEEE 802.15.4 header extensions for mesh support –additional addresses (source, destination) –sequence number –TTL („transmissions to live“) framework for chosing path selection mechanisms –path selection protocol –link metrics

24. doc.: IEEE 802.15-0503r0 Submission July 2008 L. Winkel, M. Bahr, Siemens AGSlide 24 Frame Forwarding received frames for other nodes are forwarded to the next hop according to aquired forwarding information frame forwarding capability required, realization implementation specific

25. doc.: IEEE 802.15-0503r0 Submission July 2008 L. Winkel, M. Bahr, Siemens AGSlide 25 Summary configurable distinction between factory automation and process automation propose highly efficient TDMA-based MAC scheme for factory automation –IEEE 802.15.4 PHY –very short latency through short data packets in short dedicated timeslots of fixed length –shared group timeslots –configurability mesh support for process automation