doc.: IEEE Submission January 2009 M.Bahr, N.Vicari, L.Winkel (Siemens AG)Slide 1 Project: IEEE P Working Group for Wireless Personal Area Networks (WPANs) Submission Title: Proposal for Factory Automation & MAC TG4e MAC Categories Date Submitted: 19 January 2009 Source: [Michael Bahr, Norbert Vicari, Ludwig Winkel] Company [Siemens AG] Address [Otto-Hahn-Ring 6, München, Germany] Voice: [ ], FAX: [], [bahr at siemens dot com] Re: [response to Call for Proposals doc 15-08/0373r1] Abstract:[Presentation of Proposal for Factory Automation with respect to TG4e MAC behavior categories] 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 Submission January 2009 M.Bahr, N.Vicari, L.Winkel (Siemens AG)Slide 2 Proposal for Factory Automation & TG4e MAC Categories Michael Bahr (Siemens AG) Norbert Vicari (Siemens AG) Ludwig Winkel (Siemens AG)

doc.: IEEE Submission January 2009 M.Bahr, N.Vicari, L.Winkel (Siemens AG)Slide 3 MAC Behavior Categories ACK Channel diversity –Hopping (adaptive, black lists, etc) –agility Superframe –GTS –TDMA Low Power –Low duty cycle Overhead reduction –Short MAC headers MESH support –Path diversity Time synchronization –Relative –Access to absolute time Resource Scheduling Portability –Fast association/ disassociation –Associationless Beacon scheduling Scalability taken from Jan 08, 2009 by Pat Kinney

doc.: IEEE Submission January 2009 M.Bahr, N.Vicari, L.Winkel (Siemens AG)Slide 4 Proposal for Factory Automation Goals Requirements usage in factory automation possible 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 –trade-off with latency Assumptions assume controlled envi- ronment (factory floor) configuration for optimal performance network management and frequency planning for avoidance of co-existence issues

doc.: IEEE Submission January 2009 M.Bahr, N.Vicari, L.Winkel (Siemens AG)Slide 5 Proposal for Factory Automation Main Ideas: 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 Submission January 2009 M.Bahr, N.Vicari, L.Winkel (Siemens AG)Slide 6 Proposal for Factory Automation Main Ideas: General Concept IEEE PHY frames Time Division Multiple Access –superframe with timeslots of fixed (base) length (can be brief) –shared group timeslots with CSMA –flexible configuration of superframe structure –addressing based on timeslot location or short address –modified MAC frame with very short header new frame type for differentiation reduces overhead  reduced latency Roaming capability

doc.: IEEE Submission January 2009 M.Bahr, N.Vicari, L.Winkel (Siemens AG)Slide 7 MAC Category: Superframe TDMA 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 Submission January 2009 M.Bahr, N.Vicari, L.Winkel (Siemens AG)Slide 8 MAC Category: Superframe Shared Group Timeslots more than one device per timeslot (modified) carrier sense multiple access within shared group timeslot guaranteed access for designated device 1 or more continuous timeslots concatenated to a shared group timeslot all timeslots in single shared group timeslot  network with CSMA mixture between fixed, deterministic timeslots and shared group timeslots possible further details in 15-08/0827r0

doc.: IEEE Submission January 2009 M.Bahr, N.Vicari, L.Winkel (Siemens AG)Slide 9 MAC Category: Superframe Structure existence of management timeslots configurable during setup number of (timeslots for) sensors and actuators configurable during setup

doc.: IEEE Submission January 2009 M.Bahr, N.Vicari, L.Winkel (Siemens AG)Slide 10 MAC Category: Low Power gateway considered powerful devices can go to power save during time slots that are not assigned to them sensors may go to power save during periods of inactivity –resynchronization through beacon

doc.: IEEE Submission January 2009 M.Bahr, N.Vicari, L.Winkel (Siemens AG)Slide 11 MAC Category: Overhead Reduction Very Short 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 FCS for error recognition

doc.: IEEE Submission January 2009 M.Bahr, N.Vicari, L.Winkel (Siemens AG)Slide 12 MAC Category: Overhead Reduction 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 Submission January 2009 M.Bahr, N.Vicari, L.Winkel (Siemens AG)Slide 13 MAC Category: Ressource Scheduling Transmission Modes 3 transmission modes, signalled in beacon –Discovery –Configuration –Online Discovery: network setup, addition of new devices Configuration: (re-)configuration of network and devices further details see 15-08/0571r1

doc.: IEEE Submission January 2009 M.Bahr, N.Vicari, L.Winkel (Siemens AG)Slide 14 MAC Categories: Ressource Scheduling 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 Submission January 2009 M.Bahr, N.Vicari, L.Winkel (Siemens AG)Slide 15 MAC Category: Time Synchronization only relative time synchronization to gateway needed –synchronization to start of superframe achieved through beaconing –(re)synchronization to configured superframe structure with each received beacon

doc.: IEEE Submission January 2009 M.Bahr, N.Vicari, L.Winkel (Siemens AG)Slide 16 MAC Categories: Portability & Scalability Portability Roaming between gateways associationless during operation associations established during network discovery and network configuration (transmission modes) Scalability support for up to 127/255 devices per gateway tradeoff between number of devices and superframe length

doc.: IEEE Submission January 2009 M.Bahr, N.Vicari, L.Winkel (Siemens AG)Slide 17 MAC Categories: Miscellaneous (not in the focus of this FA proposal) transparent to channel diversity mesh support not in focus of proposal –strong latency requirements more difficult to fulfill with multi- hop transmissions –see mesh support more in the area of process automation –mesh operation not forbidden, but not explicitly supported standard ACK is not touched –special ACK with shortened MAC header in new frame type defined beacon scheduling (in mesh) –not in focus of proposal –beacon collision avoidance between different gateways done by network management software or different channels

doc.: IEEE Submission January 2009 M.Bahr, N.Vicari, L.Winkel (Siemens AG)Slide 18 MAC Behavior Categories  ACK  Channel diversity –Hopping (adaptive, black lists, etc) –agility  Superframe –GTS –TDMA  Low Power –Low duty cycle  Overhead reduction –Short MAC headers  MESH support –Path diversity  Time synchronization –Relative –Access to absolute time  Resource Scheduling  Portability –Fast association/ disassociation –Associationless  Beacon scheduling  Scalability taken from Jan 08, 2009 by Pat Kinney o – not in focus of this FA proposalx – focus of this FA proposaly    – in scope of this FA proposal

doc.: IEEE Submission January 2009 M.Bahr, N.Vicari, L.Winkel (Siemens AG)Slide 19 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 September 08 IEEE e meeting 15-08/0572r0 Proposal for Factory Automation –text of proposal for factory automation 15-08/0827r0 Shared Group Timeslots –further specification of proposed shared group timeslots