doc.: IEEE /0571r1 Submission November 2008 M. Bahr, N. Vicari, L. Winkel, Siemens AGSlide 1 Project: IEEE P Working Group for Wireless Personal Area Networks (WPANs) Submission Title: [Proposal for Factory Automation ] Date Submitted: [ 10 November, 2008 ] Source: [ Ludwig Winkel, Michael Bahr, Norbert Vicari ] Company [ Siemens AG ] Address [Siemensallee 74, Karlsruhe, Germany] Voice:[ ], FAX: [ ], Re: [response to Call for Proposals doc 15-08/0373r1] Abstract:[ Proposal to IEEE e for wireless sensor/actuator networks applicable for factory automation.] Purpose:[amending for matching the requirements for factory automation] 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

doc.: IEEE /0571r1 Submission November 2008 M. Bahr, N. Vicari, L. Winkel, Siemens AGSlide 2 Proposal for Factory Automation Michael Bahr (Siemens AG) Norbert Vicari (Siemens AG) Ludwig Winkel (Siemens AG) presentation 15-08/0571r1 text 15-08/0572r0

doc.: IEEE /0571r1 Submission November 2008 M. Bahr, N. Vicari, L. Winkel, 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

doc.: IEEE /0571r1 Submission November 2008 M. Bahr, N. Vicari, L. Winkel, 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 ) is beneficial configurability of IEEE e –common base functionality –configurable for process automation use cases –configurable for factory automation use cases

doc.: IEEE /0571r1 Submission November 2008 M. Bahr, N. Vicari, L. Winkel, Siemens AGSlide 5 MAC Proposal for Factory Automation

doc.: IEEE /0571r1 Submission November 2008 M. Bahr, N. Vicari, L. Winkel, 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

doc.: IEEE /0571r1 Submission November 2008 M. Bahr, N. Vicari, L. Winkel, 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

doc.: IEEE /0571r1 Submission November 2008 M. Bahr, N. Vicari, L. Winkel, Siemens AGSlide 8 Why IEEE ? coexistence with IEEE WLAN –3 non-overlapping channels for IEEE –4 channels for IEEE sufficient range worldwide acceptance worldwide standard North America (similar worldwide)

doc.: IEEE /0571r1 Submission November 2008 M. Bahr, N. Vicari, L. Winkel, 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 –management devices (temporary)

doc.: IEEE /0571r1 Submission November 2008 M. Bahr, N. Vicari, L. Winkel, Siemens AGSlide 10 General Concept IEEE 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 Roaming capability (no channel hopping)

doc.: IEEE /0571r1 Submission November 2008 M. Bahr, N. Vicari, L. Winkel, Siemens AGSlide 11 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

doc.: IEEE /0571r1 Submission November 2008 M. Bahr, N. Vicari, L. Winkel, Siemens AGSlide 12 Shared Group Timeslots more than one device per timeslot carrier sense multiple access within shared group timeslot 1 or more continuous 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 further details in 15-08/0827r0

doc.: IEEE /0571r1 Submission November 2008 M. Bahr, N. Vicari, L. Winkel, Siemens AGSlide 13 Structure of Superframe existence of management timeslots configurable during setup number of (timeslots for) sensors and actuators configurable during setup

doc.: IEEE /0571r1 Submission November 2008 M. Bahr, N. Vicari, L. Winkel, Siemens AGSlide 14 MAC Frame Format implicit addressing through slot number –omits MAC address fields in MAC header very short MAC header of 1 byte very short PSDU increases efficiency dramatically –turnaround time / latency main criteria –every byte counts: data payload is very short assume 1 byte data payload 3 more bytes mean a 30% increase in latency! FCS for error recognition

doc.: IEEE /0571r1 Submission November 2008 M. Bahr, N. Vicari, L. Winkel, Siemens AGSlide 15 Shortened Frame Control Frame Type –corresponds to frame type subfield of IEEE –set to b100 –indicates frames with shortened MAC header Sub Frame Type –indicates frame type with shortened MAC header –beacon, command, ack, data frame

doc.: IEEE /0571r1 Submission November 2008 M. Bahr, N. Vicari, L. Winkel, Siemens AGSlide 16 Transmission modes 3 transmission modes –Discovery –Configuration –Online Transmission mode is signalled in beacon

doc.: IEEE /0571r1 Submission November 2008 M. Bahr, N. Vicari, L. Winkel, Siemens AGSlide 17 Beacon Frame Payload Online Mode Discovery / Configuration Mode

doc.: IEEE /0571r1 Submission November 2008 M. Bahr, N. Vicari, L. Winkel, Siemens AGSlide 18 Discovery mode First step in network setup (addition of new devices) Device sends its current configuration to gateway till ACK

doc.: IEEE /0571r1 Submission November 2008 M. Bahr, N. Vicari, L. Winkel, Siemens AGSlide 19 Configuration mode Second step in network setup Used for re-configuration of network Gateway sends new configuration to device

doc.: IEEE /0571r1 Submission November 2008 M. Bahr, N. Vicari, L. Winkel, Siemens AGSlide 20 Online mode Exchange of sensor data from sensors to gateway

doc.: IEEE /0571r1 Submission November 2008 M. Bahr, N. Vicari, L. Winkel, Siemens AGSlide 21 Configurable parameters Short MAC address Structure of superframe (management time slots, sensor time slots, actuator time slots) Number of time slots Duration of time slots Shared group time slots Assigned time slots Transmission channel

doc.: IEEE /0571r1 Submission November 2008 M. Bahr, N. Vicari, L. Winkel, Siemens AGSlide 22 Online mode Transmission of the actual data for factory automation (productivity data) Gateway acknowledges receipt of data from sensors in beacon (group acknowledgement) Gateway signals direction of transmission for actuator timeslots in beacon –Transmission with or without acknowledgement or with block acknowledgement

doc.: IEEE /0571r1 Submission November 2008 M. Bahr, N. Vicari, L. Winkel, Siemens AGSlide 23 Use of Single Channel Operation under the assumption of wireless channel planning 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)

doc.: IEEE /0571r1 Submission November 2008 M. Bahr, N. Vicari, L. Winkel, Siemens AGSlide 24 Considerations on Process Automation see also 15-08/409r2

doc.: IEEE /0571r1 Submission November 2008 M. Bahr, N. Vicari, L. Winkel, Siemens AGSlide 25 Mesh support Applicable for process automation IEEE 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

doc.: IEEE /0571r1 Submission November 2008 M. Bahr, N. Vicari, L. Winkel, Siemens AGSlide 26 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

doc.: IEEE /0571r1 Submission November 2008 M. Bahr, N. Vicari, L. Winkel, Siemens AGSlide 27 Summary Configurable distinction between factory automation and process automation Propose highly efficient TDMA-based MAC scheme for factory automation –IEEE PHY –very short latency through short data packets in short dedicated timeslots of fixed length –shared group timeslots –configurability Mesh support for process automation

doc.: IEEE /0571r1 Submission November 2008 M. Bahr, N. Vicari, L. Winkel, Siemens AGSlide 28 References 15-08/0503r0 Preliminary Proposal for Factory Automation –presentation of preliminary proposal for factory automation at July 08 IEEE e meeting 15-08/0571r1 Proposal for Factory Automation –presentation of proposal for factory automation at Sept/Nov 08 IEEE e meeting 15-08/0572r0 Proposal for Factory Automation –text of proposal for factory automation 15-08/0827r0 Shared Group Timeslots –presentation with further details on Shared Group Timeslots