doc.: ieee 802.15-08-0312- 15-08-0312-00-004e submission may, 2008 chol su kang, kuor-hsin chang...
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May, 2008
Chol Su Kang, Kuor-Hsin Chang (Dust Networks, Freescale)Slide 1
doc.: IEEE 802.15-08-0312-15-08-0312-00-004e
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: [Enhancement to IEEE 802.15.4-2006 for Industrial Markets]Date Submitted: [8 May, 2008]Source: [Chol Su Kang, Kuor Hsin Chang] Company [Dust Networks, Freescale]Address [30695 Huntwood Avenue, Hayward, CA 94544; 890 N. McCarthy Blvd, Suite 120, Milpitas, CA 95035]Voice:[+1 510 400 2900, +1 408 904 2705], FAX: [+1 510 489 3799, +1 408 904 2732]E-Mail:[ckang@dustnetworks.com, Kuor-Hsin.Chang@freescale.com]
Re: [n/a]
Abstract: [This document proposes requirements and features of Industrial Markets for IEEE802.15.4 MAC]
Purpose: [This document is a response to Item a) better support the industrial markets in IEEE P802.15.SG4e Call for Application]
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.
May, 2008
Chol Su Kang, Kuor-Hsin Chang (Dust Networks, Freescale)Slide 2
doc.: IEEE 802.15-08-0312-15-08-0312-00-004e
Submission
Channel Hopping TDMA for Industrial Monitoring and Control Applications
Chol Su Kang - Dust Networks
Kuor Hsin Chang - Freescale
May, 2008
May, 2008
Chol Su Kang, Kuor-Hsin Chang (Dust Networks, Freescale)Slide 3
doc.: IEEE 802.15-08-0312-15-08-0312-00-004e
Submission
Target Applications
• Equipment and process monitoring
• Non-critical control
• Diagnostics/predictive maintenance
• Asset management
May, 2008
Chol Su Kang, Kuor-Hsin Chang (Dust Networks, Freescale)Slide 4
doc.: IEEE 802.15-08-0312-15-08-0312-00-004e
Submission
Requirements
• Reliability and robustness
• Long operational life for battery powered devices (> 5 years)
• Co-existence
• Flexible and scale-able
• Coverage
May, 2008
Chol Su Kang, Kuor-Hsin Chang (Dust Networks, Freescale)Slide 5
doc.: IEEE 802.15-08-0312-15-08-0312-00-004e
Submission
Oil Refinery – Double Coker Unit
• Scope limited to Coker facility and support units spanning over 1200ft
• No repeaters were needed to ensure connectivity
• Electrical/Mechanical contractor installed per wired practices
• >5 year life on C-cell
GW
400m
May, 2008
Chol Su Kang, Kuor-Hsin Chang (Dust Networks, Freescale)Slide 6
doc.: IEEE 802.15-08-0312-15-08-0312-00-004e
Submission
TDMA
• Each device-to-device communication happens within a scheduled timeslot
• All timeslots are contained within a cycle
• Cycle of timeslots repeats in time
• CCA before transmit in each and every timeslot
Cycle
Unallocated Slot Allocated Slot
Tx
RxRX startup
Transmit Packet: Preamble, SFD, Headers, Payload, CRC
RX packet Verify CRC
Calculate ACK CRC
TransmitACK
RX startup or TX->RX
RX ACK
RX/TX turnaround
CCA: RX startup, listen, RX->TX
timeslot
May, 2008
Chol Su Kang, Kuor-Hsin Chang (Dust Networks, Freescale)Slide 7
doc.: IEEE 802.15-08-0312-15-08-0312-00-004e
Submission
TDMA Basics
• Schedule link activity• Time synchronization required for devices in
the network:– Specification on time difference tolerances– Time synchronization mechanisms
• Transmission starts at a specified time after the beginning of a slot:– Allow the source and destination to set their
frequency channel– Allow the receiver to begin listening
May, 2008
Chol Su Kang, Kuor-Hsin Chang (Dust Networks, Freescale)Slide 8
doc.: IEEE 802.15-08-0312-15-08-0312-00-004e
Submission
Channel Hopping
• Combined with TDMA to enhance reliability
11121314151617181920212223242526
802.
15.4
Ch
ann
els
CyclenCyclen-1Cyclen-2 Cyclen+1 Cyclen+2
May, 2008
Chol Su Kang, Kuor-Hsin Chang (Dust Networks, Freescale)Slide 9
doc.: IEEE 802.15-08-0312-15-08-0312-00-004e
Submission
Channel Hopping
• Frequency Diversity– Reduce the effect of Interference and
Multipath Fading
• Channel Diversity– One time slot can be used by multiple links
at the same time
• Within a network, each device has identical channel lists
May, 2008
Chol Su Kang, Kuor-Hsin Chang (Dust Networks, Freescale)Slide 10
doc.: IEEE 802.15-08-0312-15-08-0312-00-004e
Submission
CA
DA
B
C
Link = (Time Slot , Channel Offset)
A
Time
Chan.offset
BA
BA
One SlotD
• The two links from B to A are dedicated• D and C share a link for transmitting to A• The shared link does not collide with the dedicated links
BC
FE BE
BF
May, 2008
Chol Su Kang, Kuor-Hsin Chang (Dust Networks, Freescale)Slide 11
doc.: IEEE 802.15-08-0312-15-08-0312-00-004e
Submission
Channel Hopping
• Each link rotates through k available channels over k cycles.– Ch # = Chan Hopping Seq. Table ( ( ASN + Channel Offset) % Number_of_Channels )
• Blacklisting can be defined globally and locally.
Time
Ch
ann
el O
ffset
Cycle N Cycle N+1 Cycle N+2
CA
DA
BA
BA
(ch 15)
BC
BE
BF
CA
DA
BA
BA
(ch25)
BC
BE
BF
BA
BA
(ch18)
BC
ASN=N*4 ASN=N*4+1 ASN=(N+1)*4ASN=N*4+2ASN=N*4+3
May, 2008
Chol Su Kang, Kuor-Hsin Chang (Dust Networks, Freescale)Slide 12
doc.: IEEE 802.15-08-0312-15-08-0312-00-004e
Submission
Built-In Flexibility and Scalability• Trade performance and power
– Sample & reporting rate– Latency– High bandwidth connections
• Tradeoffs can vary with– Time– Location– Events
• Use power intelligently if you’ve got it– Highest performance with powered infrastructure
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