mode2 webinar

8/11/2019 mode2 webinar

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Copyright © DASH7 Alliance

Welcome to:

Mode 2 Webinar

JP Norair

18 August 2010

[email protected]

mailto:[email protected]





About the Presenter

• JP Norair

! [email protected]! skype: jpnorair

! twitter: jpdash7

• Chair of DASH7 Technology Working Group

• Chief architect of Mode 2 spec

• Leader of OpenTag project(Open source DASH7 firmware stack)

• Day job: Developer and consultant for

products using DASH7 and related

technologies (signals & systems)






Webinar Agenda

Introduction! Mission Statement

! Applications

! Design Philosophy

Technical Specs! Air Interface

! Data Interface

! Special Features

Use C! Powe

! Syste

! Partin




Mission Statement

DASH7 Mode 2Shall be a holistic technology solution

Meeting market needs of the next ten yea

For extremely versatile wireless networkWith low power and light data requireme


http://slidepdf.com/reader/full/mode2-webinar 5/47Copyright © DASH7 Alliance

Mode 2 in a Nutshell

Mode 2




Anna Cate Smith

DASH7’s Low Latency Uniquely Enables Message

Broadcasts or Multicasts) for Social Media, Mobile

Advertising and Other Apps for Things That Move




Origins

Genesis Research & Design




Research & Design Process

Outreach Working Group Technology Working Group

• Intelligent supply chain

• TPMS & other automotive

• Rights & entitlementmanagement

• Building automation &

smart energy

• Access Control

• Mobile Advertising

• etc.

• Low comm latency

• Event driven model

• Extreme low power• Excellent signal coverage

& propagation

• Ability to assess location

• Ability to use sensors

• etc.

• Yes, most of them!

• Emphasize:

- event driven

- “sessionless”

• Mo




The Power ScaleMode 2 beats the competition on power use

0 - 1 µW 1 - 10 µW 10 - 100 µW 0.1 - 1 mW 1 - 10 mW 10 - 100 mW 0.1 - 1 W 1

Runnin

3G Mod

RunningGPS chip

Upper limit for

energy harvesting

Upper limit for Multiyear battery

Li-Thionylself-discharge

Background

RF energy




Achieving Low Power

• Like all DASH7 technology, Mode 2 is designed

from the start to run on cheap batteries for

years, or alternatively, energy harvesting.

• Avoid features that blow the power budget

! Mesh (worst offender)

! Fast Frequency Hopping

! Low SNR (high data rate, high power transmit)

• Find other ways to solve the problems

! Intrinsic Long Range / High SNR

! Don’t bother trying to figure a way to develop

low-power multihop/mesh. It has been

attempted for years without much success.

! Instead, focus on low latency.

Mode 2 was designed to ru

one of these for a long, long




DASH7 Alliance Introduction

• 50+ Companies

• 23 Countries

• 10 Working Groups

• 1 Global Frequency

• 1 ISO Standard

• 1




DASH7 Alliance 2010-2011 Calendar



http://www.dash7.org/join

http://www.dash7.org/join




Agenda

Technical Specs

! Air Interface

! Data Interface

! Special Features

433 MHz

FSK / GFSK

Multichannel

28-200 kbps

Unicast &

Low L

Event-

Just 10 commands

No Application Profiles

Supports IPv6

Supports Crypto

256 byte

65 KB lon




Mode 2 PHY Feature-rich, yet uniform in design

• Designed for optimized synthesis into HW

! Packet = Preamble, Sync Word, Data

! Single Bit period across entire packet

! Uses filtered FSK (nominally GFSK)

• Designed to support different regulatory

environments, dynamically.

! Configuration of Output Power

! Configuration of available channels (up to 8)

! Out of channel power limitations

• Basic PN9 encoding, and optional FEC for

cases when max SNR budget is important.

• Similar enough to Mode 1 PHY that devices

could reasonably support both old and new

modes.




Mode 2 Transport ChannelsSupports Legacy Mode 1 PHY and Mode 2 Adjustable/Adaptable Data Rate

• Mode 2 devices su

physical channels,

• Physical channels

transport channels

• 216 kHz transport



• Control of which tr

device uses is thro

file system defaults

433.25MHz 433.50 433.75 434.00 434.25 434.50 434.75

-75

-50

-25

dB

1

Physical Channels

2 3 4 5 6 7 8

I

.

.

Transport

Channel0E

Transport

Channel10

Transport

Channel03

TransportChannel

02

Above: some example transport channels.

The Mode 2 spec defines 19 transport channels.




Revised MACWake-on, event-driven, and perfect for today’s digital RF SoC’s

• Wake-on design: ideal for asynchronous

communication in uncertain environments.

! Supports external events

(e.g. sensor alarms)

! CSMA method allows reasonably good

channel efficiency without high complexity

or recurring network handshakes.

! Synchronizer Packet method for power

efficient wakeup-request-respond

• Mostly session-less, but with:

! Filtering of adjacent networks

! Ad-hoc encoding opts. (crypto, FEC, etc)

! Data fragmentation is in protocol domain




What Exactly is Wake-on?

• Devices stay idle until some event occurs

• Returned data is never old/out-of-date

• Connectionless:

! Network synchronization is ad-hoc, not persistent

! Bursty data only: no multiplexed, streamed data

• Many kinds of wake-on events exist

! External triggers

! Internal triggers

! Active channel scan




Mode 2 Wake-on EventsMode 2 wake-on events are all internal to the device, except for Synchronizer Detect

Timed Sequences

These events may be purely sequential or keyed onto a real-time-clock (e.g. “on the 8’s”)

“External” Events

Momentary events that are triggered instantaneously by the application




• Mode 2 contains configurable strings that dictate the time sequences for:

! Sleep state active channel scan sequence (usually a slow rate)

! “Hold” state active channel scan sequence (usually a faster rate)

! Beacon transmit sequence

• Some internal processes can use the same concept

• All sequences can be locked onto a real-time-clock scheduler, in which case the sequence do

until the real-time-clock trigger occurs (e.g. “on the 8’s”)

• Example sequence is shown below (active scan), scanning three channels every 2000 ms.

Timed Sequence Method




And now:

Data, Packets, and Protocol




Packet Types

Fixed:6 bytes

up to

256 bytes

up to 65K255 frames of

256 bytes each

All frames contain CRC

Common packet str

one or more frames pe




Basic Packet Dialogs“Session” is reduced to bare minimum

• Request with optional response/ACK

• Uses default settings of the given channel

! Encoding (configurable)

! Data rate (configurable)

! Crypto (configurable)

Request Response(s) Synchronizer Request

• Synchronizer packets initialize s

! Wakes responders

! Synchronizes listen period for

! Specifies encoding/data rate/

• Session ends when dialog ends

Passive Session (e.g. Beacon) Active Session




Data Packet Dialogs An extension for bulk data transfer and encapsulating arbitrary protocols

Synchronizer(optional)

Handshake

• Protocol-based session

! May follow passive or active session

! ACK stage optional

• Handshake is managed with Mode 2 protocol

Data Frame commands

• Bulk transfer with no inherent protocol

! Batch data upload/download

! Arbitrary protocol encapsulation

! Over-the-air firmware update

• In order to maintain low complexity, there are

some limitations:

! Unicast or Anycast only

! No multihopping

Data Frame Sess




Addressing/Routing TypesSupports all major routing and addressing types

Broadcast Unicast Multicast

Requests

Responses

Beacons

Long Data Packets

Basic Queries

Sequential Queries

Multihop routing

• • •

•

•

•

•

•




Protocol Functionality

• Based mostly on search & transfer of UDB

Element data, which is kind of like XML

• Extra functionality (e.g. IPv6, sensor access)

can be managed through the UDB for

common operations or Data Packets for

complex operations.

UDB Data Access

Data Packet Handshaking

Crypto Key Exchange




Mode 2 Data Design

• Ultra-lightweight File System

! UDB: for searchable, small data

! RDB: for unstructured, larger data

• Each file contains configurable file permissions

(i.e. root/admin/guest)

• UDB has features that allow storage of default settings

• RDB is for user data

!

Very uncomplicated! File size up to 65 KB

! Random access




UDB: Universal Data Block For configuration registers and small data

• Data Attributes

! Element size up to 255 bytes

! Up to 256 Elements (files)

! All data is searchable/query-able by multicast

! All data is readable/writeable

! Elements can also be read/written/queried in batch

• Typical Contents

! Standardized & Interoperable Configuration Data

! Standardized & Interoperable Application Data! User Data

• “Application Profiles” are merely UDB configuration

combinations.




UDB Configuration: Ridding WSN of Application Profiles

Giving a Mode 2 device new a

is like teaching someone kung fu — in

Same basic device, different mem

• Estimated stack size: 8 to 32 KB, dependingon total availability of features.

• 80% of feature-set for under 16 KB (est.)

• Stack is sufficiently compact that all Mode 2

devices can basically be the same, apart

from configuration.




Mode 2 Device ClassesWay Beyond “tag & reader”

• Gateway

! Line power or rechargeable battery

! Near-zero latency

! Well-suited as a master controller for

routing, addressing, multihopping

• Subcontroller

! Rechargeable or non-rechargeable battery

! Typical worst case latency: 100 ms

!

Well-suited for aggregating data fromEndpoints and dumping to gateways

• Endpoint

! Multi-year battery or energy harvesting

! Typical worst case latency: 2 s

! Leaf node / Slave / Tag

Network Latency

P o w e r C o n s u m p t i o n Core featu

Differenc

class is in




Agen

Use C

! Powe

! Syste

! Partin




Chaos in Wireless Networks

• Mode 2 is designed to work incredibly well in

chaotic environments, although it can work well

in less chaotic environments, too.

• High Chaos

! Devices are moving around all the time

! Network gateways move, too

! Absolutely no way to maintain a connection

• WSN networks can be expensive to implement

with 802.15.4 because it is incapable of doingits job amidst chaos.

• Rethink how cost-effective your build-out can

be with a technology like DASH7 Mode 2




• In the next few slides, wireless networks are

diagrammed by the power of their components.

• High Power Components

• Fixed-location

• Multiple hours per battery charge, or no battery at all

• Medium Power Components

• Usually mobile

• Multiple days per battery charge

• Low Power Components

• Usually mobile

• Multiple years per battery charge.

Organizing IT Equipment by Power Use

circle: fixed

triangle: mobile

Supply Chain Network




Supply-Chain Network Fixed Gateways, Mobile Devices: Medium-High Chaos

Day-to-day, devices

move into, out-of, and

within the network

• Military Sup

• Perishable M

Example App

Inventory Management Network




Inventory Management Network Fixed Gateways and Devices: Low Chaos

• Possibility of devices

• Possible us

• Low netwo

• Water/irrig

• Tire pressu

• Lighting co

• Utilities mo

Example Ap

Attributes

Peer-to-Peer Real Time Location




Peer-to-Peer Real Time LocationFixed and Mobile Devices, but Fixed Gateways Only: Medium Chaos

• Moderate to large network population

• Fixed devices provide location

capabilities to mobile devices.

• Moderate network turnover

• Building automation and access control

• Manufacturing, assembly, repair,

operations

• Fleet management

Example Applications

Attributes

Just-in-Time Networks™




Just in Time NetworksMobile and Fixed Devices of Mixed Types: High Chaos.

• Moderate t

number of

• Mobile Rea

connection

• Mega ad-h

DASH7 dev

“the cloud”

gateway is

• Mobile adv

• “Social Wir

• Loyalty Pro

Example Ap

Attributes




Parting Notes

Some RF Chips that Work Well with Mode 2




Some RF Chips that Work Well with Mode 2There are many more on the way, too

ADF7023 CC1101 / CC430 SX1212 SX1230

Developer

Availability

Standard Data Rate

Turbo Data Rate

TX Filter support

RX Filter support

HW PHY support

RX Current (2.4V)

Analog TI Semtech Semtech

Q4 2010 Now Now Now

• • • •

• • •

• • •

• • • •

• • • •

13 mA 15 mA 2.5 mA 15 mA

Your Next Project Should use DASH7 Mode 2




Your Next Project Should use DASH7 Mode 2 Yet Another Nail in the Coffin for 802.15.4 as a WSN Technology

• Mode 2

! Standardized

! Interoperable

! Open source

! Designed to meet and exceed market

requirements that took dozens of

companies years to collect.

• 802.15.4, ZigBee, 15.4g, etc.

! “Alphabet Soup” of non-comp

! Weak interoperability

! Largely closed source

! An academic exercise designe

understanding real market req




Resources for Developers

What Where

OpenTag

HW Dev Kits

Product Testing

Open source firmware stack indevelopment for DASH7 Mode 2

sourceforge.net/opentag

Purchasable kits for starting

embedded design

www.ariradesign.com

www.ti.com/cc430 $

Interoperability and Compliancetesting & certification

dash7.org(via MetLabs)

Com Assoc

http://www.ti.com/cc430

http://www.ti.com/cc430




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