Doc.: IEEE 802.15-09/0667r0 Submission September 2009 Michael Bahr, Siemens AGSlide 1 Project: IEEE...
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September 2009 Michael Bahr, Siemens AG Slide 1 doc.: IEEE 802.15- 09/0667r0 Submiss ion Project: IEEE P802.15 Working Group for Wireless Personal Area Project: IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANs) Networks (WPANs) Submission Title: [ Factory Automation Subgroup Report ] Date Submitted: [22 September 2009 ] Source: [ Michael Bahr ] Company [ Siemens AG, Corporate Technology ] Address [ Otto-Hahn-Ring 6, 80200 Munich, Germany ] Voice:[ +49-89-636-49926 ], FAX: [ ], E-Mail: [ bahr et siemens dod com ] Re: [ Request for draft text for proposal for factory automation] Abstract: [ The document contains the status of the factory automation subgroup and an introduction to the draft text provided for the low latency networks proposal. ] Purpose: [] 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.
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Transcript of Doc.: IEEE 802.15-09/0667r0 Submission September 2009 Michael Bahr, Siemens AGSlide 1 Project: IEEE...
September 2009
Michael Bahr, Siemens AGSlide 1
doc.: IEEE 802.15-09/0667r0
Submission
Project: IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANs)Project: IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANs)
Submission Title: [ Factory Automation Subgroup Report ]Date Submitted: [22 September 2009 ]Source: [ Michael Bahr ] Company [ Siemens AG, Corporate Technology ]Address [ Otto-Hahn-Ring 6, 80200 Munich, Germany ]Voice:[ +49-89-636-49926 ], FAX: [ ], E-Mail: [ bahr et siemens dod com ]
Re: [ Request for draft text for proposal for factory automation]
Abstract: [ The document contains the status of the factory automation subgroup and an introduction to the draft text provided for the low latency networks proposal. ]
Purpose: []
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.
September 2009
Michael Bahr, Siemens AGSlide 2
doc.: IEEE 802.15-09/0667r0
Submission
Factory Automation Subgroup Report
Michael Bahr (Siemens AG, Corporate Technology)
September 2009
Michael Bahr, Siemens AGSlide 3
doc.: IEEE 802.15-09/0667r0
Submission
Factory Automation Subgroup
• Michael Bahr (Siemens AG)• Zafer Sahinoglu, editor (Mitsubishi Electric Research Labs)• Rudy Belliardi (Schneider Electric)• Paul Dixon (HiSilicon Technologies Co., LTD.)• Jose Gutierrez (Emerson )• Ryoji Ono (Mitsubishi Electric)• Rene Struik (Certicom) • Ludwig Winkel (Siemens AG)
September 2009
Michael Bahr, Siemens AGSlide 4
doc.: IEEE 802.15-09/0667r0
Submission
Subgroup Status
Draft text:• further completion and polishing of draft text• submitted draft text 15-09/0401r3 to TG4e editor• in normative text, transition of terminology from Factory Automation
Network to Low Latency Network• editor: Zafer Sahinoglu (Mitsubishi Electric Research Labs)
TG 4e preliminary draft:• text for low latency networks included in preliminary TG 4e draft• still some tbds
Next steps• fill remaining tbds• discuss text for this in subgroup• conference calls
September 2009
Michael Bahr, Siemens AGSlide 5
doc.: IEEE 802.15-09/0667r0
Submission
Factory Automation Draft Text Introduction
September 2009
Michael Bahr, Siemens AGSlide 6
doc.: IEEE 802.15-09/0667r0
Submission
Proposal for Factory AutomationGoals
Requirements
• usage in factory automation possible
• high determinism / low latency: – transmission of sensor data
in 10 ms for 15 devices• roaming• coexistence with IEEE 802.11• scalability in number of sensors
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
September 2009
Michael Bahr, Siemens AGSlide 7
doc.: IEEE 802.15-09/0667r0
Submission
Proposal for Factory AutomationMain 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)
Device
DeviceDevice
Device
Device
Device
Device
Gateway
Mgmt
(temporary)Device
DeviceDevice
Device
Device
Device
Device
Gateway
Mgmt
(temporary)
September 2009
Michael Bahr, Siemens AGSlide 8
doc.: IEEE 802.15-09/0667r0
Submission
Proposal for Factory AutomationMain Ideas: General Concept
• IEEE 802.15.4 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 (1 octet)
• new frame type for differentiation
• reduces overhead reduced latency
• Roaming capability
September 2009
Michael Bahr, Siemens AGSlide 9
doc.: IEEE 802.15-09/0667r0
Submission
TDMA Superframe
time
Beacon TN 1 TN 2 TN 3 TN nBeacon TN 1 TN 2 TN 3 TN n
Superframe
Beacon TN 1 TN 2 TN 3 TN nBeacon TN 1 TN 2 TN 3 TN n
Superframe
Slot
• Superframe– starts with beacon– followed by n base timeslots of equal, fixed length
• Timeslots– one device per timeslot (dedicated timeslot)– multiple devices per timeslot (shared group timeslot)– determinism
• (re-)synchronization through beacon– allows sleep mode / power save of devices
September 2009
Michael Bahr, Siemens AGSlide 10
doc.: IEEE 802.15-09/0667r0
Submission
Shared Group Timeslot
tSlotStart tSlotTxOwner tSlotTxGW
tSlotEnd
Shared Group Timeslots
• more than one device per timeslot• (simplified) carrier sense multiple access within shared group timeslot• guaranteed access for designated device, contention-based access for
other devices• 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
September 2009
Michael Bahr, Siemens AGSlide 11
doc.: IEEE 802.15-09/0667r0
Submission
Beacon
time
Sr+1 ... Sn A1 ... Amdown-
linkup-link
S1 Sr
management time slots
sensortime slots
actuatortime slots
Superframe
retransmissiontime slots
macFAmgmtTS macFAnumTimeSlots
macFAnumRetransmitTSmacFAnumActuatorTSmacFAnumSensorTS
Structure of Superframe
• existence of management timeslots configurable during setup• number of (timeslots for) sensors and actuators configurable
during setup• first sensor time slots may be reserved for dynamic
retransmissions• time slot for GACK configurable
September 2009
Michael Bahr, Siemens AGSlide 12
doc.: IEEE 802.15-09/0667r0
Submission
Very Short MAC Frame Format
PreambleFrame Length
SFD
FCSData Payload
PSDU
4 1
2
1Octets:
variable
MAC Layer
PHY Layer
Shortend Frame Control
1
• 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
September 2009
Michael Bahr, Siemens AGSlide 13
doc.: IEEE 802.15-09/0667r0
Submission
Frame Type Sub Frame Type
3 6-7
SecurityEnabled
Bits: 0-2
ACKRequest
Frame Version
54
Shortened Frame Control
• Frame Type– corresponds to frame
type subfield of IEEE 802.15.4-2006
– set to b100– indicates frames with
shortened MAC header
• Sub Frame Type– indicates frame type with
shortened MAC header– beacon, command, ack,
data frame
September 2009
Michael Bahr, Siemens AGSlide 14
doc.: IEEE 802.15-09/0667r0
Submission
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
Discovery Mode
start
Configuration Mode
OnlineMode
reconfiguration
addition of new device
mode resetmode reset
September 2009
Michael Bahr, Siemens AGSlide 15
doc.: IEEE 802.15-09/0667r0
Submission
• not part of this proposal, but would be useful• would fall into the scope of IEEE 802.15.4f/g• Problem (depending on sensitivity of receiver)
– transmissions on channel x might be received on channel (x-1), not only as interference!, due to receiver sensitivity.
– devices on channel (x-1) might consider such a transmission as belonging to their channel
– consequences for channel access
• Proposed solution– different PHY preamble depending on channel devices (chips) cannot
synchronize to received transmission on neighboring channels
channel 15
channel 16
channel 17
transmission on channel 16
devices on channel 15 recognize transmission on channel 16 as interference erronously may lead to situation where devices on channel 15 refrain from transmitting data
Worst Case: Only after channel 16 is empty, devices on channel 15 start transmitting data
A Related PHY Preamble Issue
September 2009
Michael Bahr, Siemens AGSlide 16
doc.: IEEE 802.15-09/0667r0
Submission
Changes to Standard Section 5
• 5 General Description– 5.3 Network Topologies
• added network concept for low latence networks
– 5.5. Functional Overview• 5.5.1 Superframe structure
– added description of superframe structure for low latency networks– new behavior defined when using frames with 1-octet MAC header
• 5.5.2 Data transfer model
• 5.5.3 Frame structure
September 2009
Michael Bahr, Siemens AGSlide 17
doc.: IEEE 802.15-09/0667r0
Submission
Changes to Standard Section 7
• 7.1 MAC sublayer service specification– MCPS.DATA– existing MLME primitives to be reviewed– new MLME-SFCF-SUPERFRAME-CONFIGURATION primitives
• 7.2 MAC frame formats– new frame type b100– contains four subtypes: data, ack, beacon, command– defined general frame format (7.2.1a) and individiual frame formats (7.2.2a)
• different types of acknowledgement (e.g. group ack (GACK))
• 7.3 MAC command frames– new command frames defined
• Discover Response• Configuration Response• Configuration Request• CTS Shared Group• Request to send (RTS)• Clear to Send (CTS)
September 2009
Michael Bahr, Siemens AGSlide 18
doc.: IEEE 802.15-09/0667r0
Submission
Changes to Standard Section 7
• 7.4 MAC constants and PIB attributes– new MAC constants defined
• macFAlowlatencePAN
• macFAnumTimeSlots
• macFAnumSensorTS
• macFAnumRetransmitTS
• macFAnumActuatorTS
• macFAmgmtTS
– probably missed some
September 2009
Michael Bahr, Siemens AGSlide 19
doc.: IEEE 802.15-09/0667r0
Submission
Changes to Standard Section 7
• 7.5 MAC functional description– 7.5.1 Channel access
• new clause „Superframe structure with beacons with shortened frame control”– superframe definition– timeslot description– channel access in dedicated and shared group timeslots
– 7.5.1.4 CSMA-CA algorithm• extension with simplified scheme for shared group timeslots (tbd)
– 7.5.7a Transmission modes in factory automation networks• new clause describing discover, configuration, and online modes
– 7.5.2 Starting and maintaining PANs– 7.5.3 Association and disassociation– 7.5.4 Synchronization– 7.5.5 Transaction handling– 7.5.6 Transmission, reception, and acknowledgement
• need to be reviewed and extended if necessary
• 7.7 Message sequence charts– to be done
September 2009
Michael Bahr, Siemens AGSlide 20
doc.: IEEE 802.15-09/0667r0
Submission
Changes to Standard Annex
• Annex D PICS proforma– to be done at the end
• Annex Fa (informative)– motivation and lyrical explanation for factory automation networks
September 2009
Michael Bahr, Siemens AGSlide 21
doc.: IEEE 802.15-09/0667r0
Submission
References
• 15-09-0411-02 „ Factory Automation Draft Text Introduction”
• 15-09-0401-03 „Draft Text for Factory Automation“• 15-09-0228-00 “Proposal for Factory Automation“• 15-08-0254-01 “Proposal for Factory Automation“• 15-08-0827-00 „Shared Group Timeslots”• 15-08-0420-00 „Extending the MAC Superframe of
802.15.4 Spec”• 15-09-0199-00 „ Factory Automation Sub-Group
Deliverables”• 15-09-0024-00 „Proposal for Factory Automation & MAC
TG4e MAC Categories”
