dash7 alliance university working group magazine - may 2012

UWGM A G A Z I N E 2012

MAY

2

8th

F i r s t i s s u e o f U n i v e r s i t y W o r k i n g G r o u p ( U W G ) t e c h n i c a l m a g a z i n e

DASH7 Localization

RFID tags for ubiquitous applications

OpenNode-433

How to get started with OpenTag

Unifying the world of 433MHz

Inside this issue...

Message from the President, DASH7 Alliance by Pat Burns

1

Message from UWG Co‐chairs by Chanaka Lloyd, Pere Tuset

4

How to get started with OpenTag 5 by Hwa‐kyung Lee Small form‐factor DASH7 RFID tags for ubiquitous applications 9 by Chanaka Lloyd OpenNode‐433, a 433 MHz development platform 12 by Pere Tuset DASH7 applications 20 by Javier Palafox Opportunistic Infrastructure‐Based DASH7 Mode 2 Localization 24 by Maarten Weyn DASH7 UWG families 29 Get in touch with UWG 31

DASH7 Alliance University Working Group

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Message from the president

Pat Burns President, DASH7 Alliance

I was invited to contribute something erudite for the first UWG magazine, and I

wanted to be part of another historic DASH7 moment. First, I have to comment

on how awesome our University Working Group is turning out for the DASH7

Alliance. While we have engaged with various universities around the world since

the founding of the alliance in 2009, it has only been in the last year that we've

seen such terrific contributions and energy from this group, perhaps due to the

"launch" of the UWG program last May, which has resulted in a large number of

student members. Obviously, some of the most important technology

innovations in history have achieved real momentum from contributions at the

University level and DASH7 appears to be no different. At least one of our

members is studying the correlation between beer consumption and DASH7

developer productivity and I'm told that UWG members are showing the

strongest correlations … this is shocking to me and I am awaiting a deeper

analysis of this news.

The availability of the Mode 2 spec, OpenTag, and the maturity of the alliance

made the formation of the UWG last spring more viable than, say, what might

have been possible in 2010. And really, the beta release of OpenTag in

September 2011 marks an important milestone where many students have

found it easy to get involved with DASH7. Finally, last month we "open sourced"


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the Mode 2 draft 12 spec, effectively opening the spec up to everyone in the

world – no alliance membership required. So we have done just about

everything imaginable to make DASH7 accessible to college kids short of shipping

dev kits with a complimentary bong. Now the world is watching to see if this

next generation is going to put up big innovations or if they are, as many suspect,

just expert video gamers.

At least a few of our UWG members are going to graduate at some point from

school—professional students may be lurking among them—but most will be

forced to actually, you know, get a job. For those that have not already found

job opportunities as a result of participating in the alliance, here are some

thoughts on post‐university DASH7 business opportunities.

One word: phones. All the 90's‐era network theory you may have been taught

in school should be unlearned in the case of DASH7, where mobile handsets are

what will drive massive adoption of wireless sensor networks. Today, WSN is a

ridiculous hodgepodge of proprietary technologies or semi‐complete stacks

masquerading as "standards". Sooner than later, developers will grow weary of

trying to force‐fit WiFi or Bluetooth into WSN apps where they frankly just don't

belong. DASH7 has an enormous opportunity to fill the white space between

those technologies and others like NFC or GPS since a) the number of sensors in

the world is growing exponentially, b) those sensors will be overwhelmingly

connected wirelessly, and c) the means for collecting sensor data will take place

at a frequency below 1 GHz and most likely below 600 MHz. In terms of global

standards, DASH7 is one of the few (or perhaps the only?) standards that can

meet the optimal mix of frequency, protocol required to support massively

scalable public WSN infrastructure.

Another word: interoperability. Customers can't get too excited about WSN's if

it means spending $$$ on systems integration to interconnect dozens of

proprietary networks. Interoperability is an essential element to widespread

adoption of WSNs around the world and the myopia of the existing WSN industry

to this is a poorly‐kept secret and something that a young graduate can

exploit. A related point on interoperability is the growing importance of public


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networks: while most WSN systems today are "closed loop" networks, the

skyrocketing use of "Bring Your Own Device" (BYOD) in enterprise environments,

the access by many employees of public networks like Twitter, and the blurring

of lines between employees, contractors, vendors, and customers means "closed

loops" will increasingly need to find ways to be more "open".

A related word: ease of use. Yes, this sounds like another gassy cliché but like

interoperability, the industry has not found the collective ability to make it easy

to deploy and maintain WSN solutions. Mostly, deploying is a massive labor

challenge (device costs pale in comparison) and maintenance is a "special"

skill. Better to think in terms of how the smallest of companies might view

adopting WSN technology—not unlike the way they bring devices they already

understand like an iPad to the office—like consumers. Basically, the

consumerization of WSN. Sounds far‐ fetched to some of you, but BYOD—and

increasingly, Bring Your Own Application—is the default operating mode at the

world's finest companies. And the winning BYOD platforms are those that are

easiest to deploy, use, and maintain. The most rapidly growing WSN

technologies will be the ones that are most consumer friendly, not unlike

Bluetooth or WiFi for their respective use cases.

So, phones, interoperability, and ease of use. Those are my words of DASH7

advice for the career‐minded college readers of this soon‐to‐be‐famous

magazine. BTW ‐ If you are reading this and are not a member of the DASH7

Alliance UWG, I strongly suggest getting involved. The price is right, the

networking is excellent, and the learning opportunities (and job opportunities, it

seems, abound, but no promises). I recently stepped down as Chairman of the

Alliance after 3+ years and this is a terrific group with some amazing stuff in the

works. My own venture, Blackbird Technology, aims to be an important part of

the DASH7 ecosystem in the months and years ahead, but I know that some of

the most exciting work we are going to see is cooking in a dorm or lab right now

or in the near future.


4

Message from UWG Co‐chairs

Chanaka Lloyd Co‐chair UWG

Pere Tuset Co‐chair UWG

Congratulations! You are reading the first issue of the UWG Magazine, a

technical magazine to publish the research work of DASH7 UWG members.

After the DASH7 winter meeting (December 2011) in Mataró, Spain, we decided

to come up with our own technical magazine. We wanted to provide the

researchers and academics involved in the UWG a facility to publish their work,

and to let the other members and non‐members interested in DASH7 know of

the ongoing research work.

At the infancy of this magazine, it is only a biannual publication. So, we’ll come

back to you in December with more interesting DASH7 research outcome.

Enjoy…and please provide us with your feedback – we value it!


5

How to get started with OpenTag

Hwa‐kyung Lee

UWG Member ENS Lab, Pusan National University, South Korea

What’s OpenTag?

OpenTag, an open source firmware library with demo application for implementing ISO 18000‐7 Mode2 on embedded hardware, is now available in beta2. OpenTag is written entirely in C and can be ported to 8, 16, or 32 bit platforms.

What are main modules & where can you find them?

Before we start using OpenTag, it is helpful that you the understand components of the project structure. I’ll explain this based on CCSv5 (Code Composer Studio). Below is a picture of the project file. And I added some explanations to it.

I’ll introduce one simple example. That is “The way to use LED”. Now I’m using EM430RF board of TI.

So at first, you must select the board specific code. In my case, I chose the “board_EM430RF.h” file, because LED port number can be different with each board.

Next, you need to initiate ports that you will use. The function name is

User Main

Board specific code

System event manager

Fully abstracted

HW‐specific code(MCU)

HW‐specific code(Radio)


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“platform_init_gpio”. It’s in “platform_CC430.c” file.

Finally, when you call some functions that can control DOUT, your LED will be On/Off. The functions isdescripted below.

OT_TRIG1_PORT and OT_TRIG1_PIN definitions are changed by board specific code that I already explained.

Let’s turn on the LED. Just insert “platform_trig1_high()” function at the main function. After that, complie the code and run it. The outcome is below.

I changed “board_EM430RF.h” because it isn’t exactly fit in my evaluation board.

When you change this port and pin description, you should look into the specification or schematic of board.

And, there is another example. That is “Beacon Transmission”.

Before we start it, we need to make some packet frames and transmit sessions. For this, we must know “sys_event_manager” function in “OTkernel/~Native/System.c” file.

“sys_event_manager” takes the role of managing system events such as checking new session, initializing transmission or reception events, etc.

This function divides events into seven categories. And for

ot_uint sys_event_manager(ot_uint elapsed){ do{ switch(sub_clock_tasks(elapsed)){ caseTASK_idle: … caseTASK_processing: …

caseTASK_radio: … caseTASK_session: … caseTASK_hold : … caseTASK_sleep: … caseTASK_beacon: … default :…

} }

}

#define OT_TRIG1_PORTNUM 1 #define OT_TRIG1_PIN GPIO_Pin_0

void platform_trig1_high () {OT_TRIG1_PORT‐>DOUT |= OT_TRIG1_PIN;} void platform_trig1_low () {OT_TRIG1_PORT‐>DOUT&= ~OT_TRIG1_PIN;} void platform_trig1_toggle () {OT_TRIG1_PORT‐>DOUT ^= OT_TRIG1_PIN;}

void platform_init_gpio (){ //

OT_TRIG1_PORT‐>DOUT &= ~(OT_TRIG1_PIN); OT_TRIG1_PORT‐>REN &= ~(OT_TRIG1_PIN); OT_TRIG1_PORT‐>DIR |= OT_TRIG1_PIN; OT_TRIG1_PORT‐>DS |= OT_TRIG1_PIN;

}


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transmitting beacon, we need to enter TASK_beacon.

“sub_clock_tasks” function assign category. TASK_idle has the lowest priority and TASK_processing has the highest priority. For achieving TASK_beacon, other higher conditions are disabled. That is the first thing you have to do.

Next, when the event enters to TASK_beacon, “sysevt_beacon” is executed. This function adds new TX session and make frame packet for beacon. It leads beacon event to TASK_session. Finally, it will go to TASK_radio, then radio state moves to TX.

Like this way, you can do many things in the OpenTag.

If you want to make an application that work on OT, you develop it at the user main code in App_Code.

The applications that you make are managed by system event manager in OTkernel/~Native/. It creates events, initiates them, and manages the time of events.

The event’s key work is receiving or transmitting some information. You need to control radio state, buffer etc. And, you can find it in OTradio.

ot_uintsub_clock_tasks (ot_uint elapsed)){ Task_Index output = TASK_idle; #If (M2_FEATURE(BEACONS)==ENABLED) …output= TASK_beacon;

#endif #If (M2_FEATURE(ENDPOINT)==ENABLED) …output= TASK_sleep;

#endif #If (SYS_RECEIVE ==ENABLED) …output= TASK_hold;

#endif If (session_refresh(elapsed) ) …output= TASK_session;

If (sys.evt.RFA.event_no != 0 ) …output= TASK_radio;

If (sys.mutex == SYS_MUTEX_PROCESSING)

…output= TASK_processing; returnoutput; } }


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And you need to make packets for communication. OTlib has many modules for OT. It has many data structures, frame making functions, mpipe, API and so on.

What are tools required for OpenTag development?

OpenTag Beta2 gives 3 kinds of project files. CB(Code Blocks), CCS (Code Composer Studio), RIDE7 (Raisonance Integrated Development Environment). If you want to use cc430 platform then you use CCS or CB. And, for other information about compiler, please enter homepages below.

CCS:http://www.ti.com/tool/ccstudio?247SEM CB:http://www.codeblocks.org/ RIDE7:http://www.raisonance.com/

Where to get help?

SourceForge. http://sourceforge.com/projects/Opentag

Dash7 Alliance – OpenTag

http://dash7.org/index.php?option=com_content&view=article&id=130&Itemid=193

Wiki of Indigresso

http://www.indigresso.com/wiki/doku.php

About the author:

Hwa‐kyung Lee is Master Degree Student in computer science and engineering at Pusan National University, South Korea. Her research interests are Active RFID and Energy harvesting. Now she is working on PCB design and implementing OpenTag applications.


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Small form‐factor DASH7 RFID tags for

ubiquitous applications

Chanaka Lloyd Co‐chair UWG PhD student IMSAS, University of Bremen, Germany

UWG participation

September 2011: that’s the month

that I became one of the co‐chairs in

the University Working Group (UWG)

of DASH7. And that’s the month that

I began pursuing DASH7 as one of

my research interest.

DASH7 being rather a new research

avenue, and with my research

interests set on embedded systems,

it was immediately clear to me how I

could participate in UWG with

research in electronics.

After my participation in the DASH7

winter meeting (December 2011) in

Mataró, Spain, I was able to

convince many other researchers in

the University of Bremen to join

hands in DASH research. In addition,

my institute, IMSAS (Institute for

Microsensors, ‐actuators and ‐

systems) initiated a collaborative

research program with ENS Lab, PNU

(Pusan National University), South

Korea. We officially initiated the

program with couple of internships

for Javier Palafox and myself in PNU

from January to April 2012. That’s

where the small form‐factor, self‐

reliant, active RFID was designed.

Ubiquitous application

At present day, the requirement for

wireless sensor nodes is immense,

but the application‐specific supply of

wireless sensors for such demand is

low or too expensive to adopt. Most


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of the applications have one thing in

common: ubiquitous data collection.

Applications need to collect specific

parametric data (say, temperature,

humidity, acceleration, color, airflow,

etc.) to make certain decisions, but

they also demand such data

collection at a low price and low

maintenance. DASH7 is inherently

capable of offering the solution to

satisfy such requirements.

HVAC systems, Littoral applications,

Infrastructure monitoring, People

flow, etc. are some of the

applications which demand

ubiquitous data collection.

Self‐reliant DASH7 RFID tag

The completed 433 MHz DASH7 RFID

design is meant for ubiquitous

applications. A feature that is high in

demand for any RFID tag is low

maintenance. For that, tags need to

be robust during operation and

capable of operating unattended for

long periods; therefore, they need to

be self‐reliant, meaning the ability to

harvest energy and recharge its own

power unit.

Also, in most cases, tags need to be

discreet, or small, in appearance.

The design under discussion was

deliberately made to be small in size

to satisfy that purpose. Standard

0603 components were used for the

embedded design. In addition, it has

a CC430F5137 16‐bit microcontroller

with 32 KB flash memory; onboard

temperature sensor with provision

to connect a variety of other sensors

(e.g. thermal airflow sensors);

Max17710 charger/protector for

energy harvesting module; solar

panel, with provision for the

attachment of thermal and vibration

harvesters; 8 Mbit external flash

storage for data logging; LED

indicators (can be disabled); and,

dual power system of Thinergy™

MEC201 battery and coin cell

battery for applications where

energy harvesting is not feasible. In

addition, it has a JTAG port

connectible via a FPC flat cable for

reading/writing and programming

the tag

The design uses the concept of

layered design. It has 4 layers: main

electronics with the microcontroller

layer, antenna layer, solar panel and

battery (MEC201 or coin battery).

The 4 layers stack up on each other

making it a little over 1 cm. length


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and width of the design is approx. 3

x 3.5 cm.

Production and field trials

The tag is currently being produced,

and system testing is planned in the

coming months.

IMSAS is involved in the Intelligent

Container project

(http://www.intelligentcontainer.co

m/). Its research involves the testing

of WSNs inside containers full of

fresh bananas. The tag is expected

to undergo a round of extensive

testing in November‐December 2012.

Future demonstrations

Tag will be demonstrated in the

coming DASH7 meetings in order to

exemplify the variety of applications

that is made possible by such a small

tag design with energy harvesting

capabilities. So, stay tuned with

DASH7 and UWG news if you are

interested in observing the work of a

state‐of‐the‐art tag in operation.

About the author:

Chanaka Lloyd is a PhD student in the Institute for Microsensors, ‐actuators and ‐systems (IMSAS),

University of Bremen, Germany. He has a MSc in information and automation engineering from

the University of Bremen, Germany and a BSc in electrical engineering from the University of

Moratuwa, Sri Lanka. His doctoral studies are in airflow pattern profiling inside refrigerated

containers transporting fresh produce. His research interests include miniature wireless

embedded systems, application specific DASH7 RFID tags and energy‐harvesting for self‐

sustainable active RFID tags.


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OpenNode‐433: A development platform for

Wireless Sensor Networks at the 433 MHz band

using DASH7 Mode 2

Pere Tuset and Xavier Vilajosana‐Guillén

Distributed, Parallel and Collaborative Systems (DPCS) Group Universitat Oberta de Catalunya

Introduction

For the last decade the development of Wireless Sensor Networks (WSN) has been tightly linked to the evolution of the IEEE 802.15.4 standard [1], which appeared back in 2003. IEEE 802.15.4 defines the physical and data‐link layers of the OSI communications model and is targeted at Low‐Rate Wireless Personal Area Networks (LR‐WPAN), e.g. low‐cost and low‐power embedded devices that require ubiquitous low‐speed and short‐range wireless communications. Different wireless technologies already use the IEEE 802.15.4 standard as the physical and data‐link layers of their communications

stack, e.g. ZigBee, WirelessHART and ISA100.11a.

At the physical layer the first revision of the standard (IEEE 802.15.4‐2003 [1]) proposed the use of two different frequencies from the Industrial, Scientific and Medic (ISM) band, namely 915 MHz and 2.45 GHz, and the European 868 MHz band. The 2.45 GHz band, which is available worldwide, is divided into sixteen 5 MHz channels (11‐26) and offers a data rate of 250 kbps using an Offset Quadrature Phase Shift Keying (OQPSK) modulation scheme with Direct Sequence Spread Spectrum (DSSS). The 915 MHz band, only available in North America (Region 1), offers ten 2 MHz


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channels (1‐10) with a data rate of 40 kbps using a Binary Phase Shift Keying (BPSK) modulation scheme with DSSS. Finally, the 868 MHz band, which is only available in Europe, offers a single 2 MHz channel (0) with a data rate of 20 kbps using a BPSK modulation scheme with DSSS. Later on, the second revision of the standard (IEEE 802.15.4‐2006 [1]) improved the available channels and data rates of the 868/915 MHz bands. The 915 MHz band now has thirty channels available and both the 868 MHz and 915 MHz bands can operate at data rates of 100 kbps and 250 kbps respectively thanks to the use of OQPSK modulation with DSSS.

At the data‐link layer the IEEE 801.15.4‐2003 standard defines the services required to enable nodes join and leave the LR‐WPAN network, as well as to transmit data frames between them while sharing the wireless medium gracefully. The standard also defines the types and format of the data frames that are exchanged during communication between nodes (e.g. data, beacon, acknowledgment, command). Two device types, Reduced Function Devices (RFD) and Full Function Devices (FFD), are also defined in the standard. On the one hand RFD are equipped with sensor and actuators and can only communicate with FFD.

On the other hand, FFD are equipped with all the data‐link layer functions (as well as sensors and actuators) and, thus, can either act as simple network nodes or as network coordinators. Using these devices two different network topologies can be built, star and mesh networks. On the one hand, in a star network one FFD acts as the Personal Area Network (PAN) coordinator and both FFD and RFD can only talk to the PAN coordinator in order to exchange data between them. On the other hand, in a mesh network all FFD nodes can exchange data between them at any time, which enables to extend the network coverage by means of using multi‐hop communications (e.g. by using a combination of packet forwarding at the data‐link layer and packet routing at the network layer).

DASH7 Mode 2: Wireless Sensor Networks at the 433 MHz band

Experience has proven that for certain WSN applications neither the 2.45 GHz band nor the 868/915 MHz bands defined by the IEEE 802.15.4 standard physical layer are sufficient to cover the different uses cases that exist. For example, the 2.45 GHz band suffers from bad signal propagation characteristics, especially in indoor environments where metal surfaces or liquids are present. In addition, WSN devices at


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the 2.45 GHz band have to cope with broadband interference from other ubiquitous wireless technologies operating at the same band, e.g. IEEE 802.11 (Wi‐Fi) and IEEE 802.15.1 (Bluetooth), which degrades its overall performance. While the 868/915 MHz bands have better signal propagation characteristics than 2.45 GHz, these bands are only available in Europe and the United States respectively, which certainly limits the potential impact of developed products. Moreover, the European 868 MHz band must cope with interference from television broadcasting and mobile broadband systems, which can also degrade its performance.

Equally important, the data‐link layer of the IEEE 802.15.4 standard is not well suited for certain wireless communication scenarios that are of interest in the WSN domain. The star topology is limited to single‐hop communications, e.g. two nodes communicating through the PAN coordinator, and limits the overall range of the network, rendering it not viable for scenarios where large areas need to be covered. Yet despite the potential benefits of mesh topology, the range of the network can only be extended by means of forwarding packets, thereby forcing neighbor nodes to waste valuable (battery) energy in

the process, making it difficult to maintain the low‐power profile required by such types of network.

Taking all of the above into account, DASH7 Mode 2 [2] appears as a promising wireless technology to enable next generation WSN applications. Not only does it operate at the 433 MHz band, yielding better signal propagation in harsh environments and being freely available worldwide, but it also offers a complete communications stack (from physical to application layer) capable of handling bursty, light‐data, asynchronous and transient usage models for both fixed and mobile nodes while being simple, reliable and maintaining a low‐power profile.

OpenNode‐433: A development board for WSN at the 433 MHz band

Looking to the past it seems clear that, apart from simulations, the huge advances seen in the WSN field during the last decade have been in part thanks to having a unified development platform. T hat is, both the hardware and the software that are needed to build and evaluate real‐world deployments. For instance, thanks to these real‐world deployments researchers have been able to develop adaptive data‐link layer protocols that are more robust to time‐varying frequency selective


15

interference at the physical layer, e.g. by using Frequency Hopping Spread Spectrum (FHSS) like in IEEE 802.15.4e [3].

On the hardware side one of the most prominent development platforms has been the TelosB [4], designed at University of California at Berkeley (UCB) in 2004 and later commercialized by Crossbow Technologies. The TelosB mote features a Texas Instruments MSP430 16‐bit microcontroller with 10 Kbytes of RAM and 48 Kbytes of Flash respectively. The wireless communications part of TelosB is addressed with a Texas Instruments CC2420 transceiver fully compatible with IEEE 802.15.4 standard operating at the 2.45 GHz band and with a maximum transmit power of 0 dBm. Additionally, TelosB comes with temperature, humidity and light sensors, as well as a 2xAA battery holder that enables the nodes to operate autonomously.

Figure 1 ‐ A TelosB board

On the software side the de facto

embedded operating system for WSN has been TinyOS [5], also developed at University of California at Berkeley (UCB). Another player to take into account in the embedded operating system for WSNs domain is ContikiOS [6], which was developed by Adam Dunkels at the Swedish Institute of Computer Science. Both TinyOS and Contiki are developed in C, distributed under an open source license (BSD License) and are targeted at microcontrollers with low processing power, small available memory and limited energy availability. In addition to the embedded operating system they include support for different upper‐layer protocols, e.g. Low‐Power Internet Protocol version 6 (6LoWPAN) and the COnstrained Application Protocol (COAP).

Unfortunately, at the moment of writing this article the situation is not fully satisfactory for WSN at the 433 MHz band using DASH7 Mode 2. Part of the puzzle is already solved, e.g. OpenTag [7], an open source implementation of the DASH7 Mode 2 protocol, is already available and is currently being extensively tested. Nevertheless, the other part of the puzzle, e.g. the development board, has not been yet properly addressed. It is true that some development boards already exist, e.g. the DASH7 Mode 2 development kit provided by


16

Agaidi [8], but none include all the components required to develop a complete WSN prototype, e.g. sensors, battery holder and programming interface, among many others. Thus, in order to ease research and development of WSN at the 433 MHz band based on DASH7 Mode 2 and OpenTag, the Distributed, Parallel and Collaborative Systems (DPCS) group of Universitat Oberta de Catalunya (UOC) [9], member of the DASH7 Alliance University Working Group (UWG), together with Wayra Networks [10], member of the DASH7 Alliance, have designed OpenNode‐433, a fully‐featured development board that is intended to become to DASH7 Mode 2 and OpenTag what the TelosB mote and TinyOS operating system have been to the development of WSN using the IEEE 802.15.4 standard at the 2.45 GHz band.

From a technical point of view, the OpenNode‐433 board is based on a 32‐bit Cortex‐M3 microcontroller, which can operate up to 72 MHz and comes with 20 Kbytes of RAM and 128 Kbytes of Flash memory respectively. On the communications side the first version of OpenNode‐433 will be based on the Texas Instruments CC1101 transceiver, which can operate at the Sub‐1GHz band (e.g.

315 MHz, 433 MHz, 868 MHz and 915 MHz) with a transmit power up to 10 dBm. Future versions of the OpenNode‐433 board will be designed with other wireless transceivers, such as the Semtech SX123x or the Melexis MLX72013, to enable for DASH7 Mode 2 compatibility testing among different transceivers. One interesting aspect of the board is that the antenna is not soldered; instead, a 50 Ohm SMA female connector is available to enable connecting different types of antennas for testing purposes. In addition to that, OpenNode‐433 comes with temperature, humidity and acceleration sensors, as well as four external pins to interface other types of sensors with the internal 12‐bit Analog‐to‐Digital Converter (ADC). Last but not least, the board comes with a 2xAAA battery holder, a mini‐USB connection and a power supply connection, which enables it to operate autonomously, connected to a computer or connected to a power supply. Overall the OpenNode‐433 board measures around 6,5x3x3 centimeters and weights less than 75 grams (with 2xAAA batteries included and antenna excluded).


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Figure 2 ‐ An OpenNode‐433 board

Taking into account the technical specifications of OpenNode‐433 it seems unnecessary to remark that the board is fully compatible with the DASH7 Mode 2 specification, meaning that all the devices (Blinker, Endpoint, Subcontroller and Gateway) can be implemented. For instance, one node can be programmed as a Blinker and operate autonomously from batteries, whereas another node can be programmed as a Gateway and be powered from the computer through the USB port and serve as an interface to other networks, i.e. the Internet. Nevertheless, at the moment of writing OpenTag, the main implementation of the DASH7 Mode 2 protocol, has not yet been ported to OpenNode‐433, but that is expected to change over the course of this summer.

Conclusions and future work

Until today most research and development in WSN has taken place at the 2.45 GHz band using the

IEEE 802.15.4 standard mainly because of the availability of development boards, e.g. TelosB. Nevertheless, neither the 868/915 MHz bands nor the 2.45 GHz band are well suited for all the use cases in the WSN domain. An alternative to IEEE 802.15.4 for WSN applications is DASH7 Mode 2. Not only does it use the 433 MHz band, with better propagation characteristics and worldwide availability, but it also provides a data‐link layer that is well‐suited to handle bursty, light‐data, asynchronous and transient usage models for both fixed and mobile nodes while being simple, reliable and maintaining a low‐power profile.

Unfortunately, research and development based on the DASH7 Mode 2 standard has been impaired due to the lack of a fully‐featured development board available to developers. To improve this situation we are introducing OpenNode‐433, a development board that is fully compatible with the DASH7 Mode 2 standard and OpenTag. Thus, we expect the board to become a reference board for DASH7 Mode 2 and OpenTag research, development and compatibility testing in the near future. The OpenNode‐433 board will be available from Wayra Networks beginning the third quarter of 2012 with a price will that


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is similar to development boards for the IEEE 802.15.4 standard.

Nevertheless, despite the leap forward that having both a full‐featured development board (OpenNode‐433) and an open source stack implementation (OpenTag) for DASH7 Mode 2 represents, there are still many aspects that need to be further investigated in order to have a proper knowledge of the uses cases in which it can be successfully used. For instance, propagation characteristics of the 433 MHz band in different environments, both indoor and outdoor, for the different channel types defined by DASH7 Mode 2 need to be investigated to have empirical models that can be used in real‐world deployments. Hopefully all these matters will start to be properly addressed now that a reference development board and software stack is available to the DASH7 community. One important player for that to happen can be the University Working Group (UWG), which is currently starting to address all these matters in order to provide better understanding of the technology, as well as designing new services that are based on it.

References

[1] IEEE 802.15.4‐2003 Standard. Available on‐line at [http://www.ieee802.org/15/pub/T

G4.html].

[2] DASH7 Mode 2 Draft 12 Specification. Available online at [http://www.dash7.org/].

[3] IEEE 802.15.4e Standard. Available on‐line at [http://www.ieee802.org/15/pub/TG4e.html].

[4] J.Polastre, R. Szewczyk, D. Culler. Telos, enabling ultra‐low power wireless research. Proceedings of the 4th international symposium on information processing in sensor networks.

[5] TinyOS, an operating system for tiny embedded networked sensors. Available online at [http://www.tinyos.net/].

[6] ContikiOS, the operating system for the Internet of Things. Available online at [http://www.contiki‐os.org/].

[7] OpenTag, full‐featured communications stack for DASH7 Mode 2. Available online at [http://sourceforge.net/projects/opentag/].

[8] Agaidi DASH7 Mode 2 development kit. Available online at [http://www.agaidi.com/].

[9] Distributed, Parallel and Collaborative Systems (DPCS) Group, Universitat Oberta de Catalunya (UOC). Available online at


19

[http://dpcs.uoc.edu].

[10] Wayra Networks. Available online at [http://www.wayranetworks.com/].

Acknowledgments

The authors of the paper want to acknowledge Fernando Luis and Joan Tobeña, from Wayra Networks for their invaluable collaboration in the development and production of OpenNode‐433.

About the authors:

Pere Tuset‐Peiró is a PhD candidate at the Distributed, Parallel and Collaborative Systems (DPCS) group of Universitat Oberta de Catalunya (UOC), part‐time lecturer at Escola Universitària Politècnica de Mataró (EUPMt) and co‐chair of the DASH7 Alliance University Working Group (UWG). For his PhD thesis, he is working on low‐power wireless communication technologies at 433 MHz band, including DASH7 Mode 2.

Dr. Xavier Vilajosana‐Guillén is an associated professor at the Computer Science, Multimedia and Telecommunication Department of Universitat Oberta de Catalunya (UOC). Currently, he is a Fullbright visitor at University of California at Berkeley (UCB) where he does research in the Berkeley OpenWSN project, which intends to build an open implementation of hardware and software for the Internet of Things.


20

DASH7 applications

Javier Palafox

PhD student UWG member IMSAS, University of Bremen, Germany

“Let the future tell the truth, and

evaluate each one according to his

work and accomplishments. The

present is theirs; the future, for

which I have really worked, is mine.”

Nikola Tesla, Serbian Inventor and

Engineer

With the already existing wireless

technologies in the market, it might

come as a surprise that yet another

wireless‐networking scheme, called

Dash7, is joining the fray.

The main figures of merit of DASH7

devices that make them ideal for

wireless sensor networking

applications resides on the excellent

wave propagation on unlicensed

433MHz, their low energy

consumption and their low

dependency from a fixed

infrastructure. The only

disadvantage of Dash 7 is that it

cannot handle high‐bandwidth data

transfers.


21

So, what applications are best suited

to adopt DASH7 technology? And

more importantly, what is the

reason for its adoption by the

developers and consumers?

DASH7 is designed to provide multi‐

year battery life, low device costs,

transmit/receive over very long

ranges, and for applications that

does not require high data rate or

complex routing algorithms. Six

segments — Building Automation,

Smart Energy, Location‐Based

Services, Mobile advertising,

Automotive and Logistics — are

accounted promising.

Location‐Based Services

Commercial products can take

advantage of the small footprint,

low power, long range, and low cost

of DASH7. It is being used today for

developing new location‐based

services using a range of DASH7‐

enabled devices including

smartcards, tickets, and other

conventional products.

The practicality of “check‐in” of

other technologies is limited in

urban environments and the

coverage usually fails indoors. As an

example Agaidi is developing Dash7‐

based and easy‐to‐use devices that

do not need wired charging at

Helsinki airport.

Location‐based services like

Foursquare, Novitaz, or Facebook

can exploit DASH7 and award loyalty

points.

Mobile advertising

Retailers are in the forefront of RFID

adoption. They have been realizing

the benefits from the long distance

mobile advertising and mobile

coupons.

They can attract prospective

customers by sending information

about their products with the help

of RFID tags. Just like in blockbuster

movie Minority Report’s futuristic

view; a billboard could display an ad

that is customized particularly for

that person.

The RFID chips are being built into

credit cards and cell phones as a

means of storing data that is

accessible by contact‐free sensors.

Advertising groups view it as a way

to make advertising more relevant

to the user.


22

Automotive

Using 2.4 GHz in work environments

with large amounts of metallic

clutter is not a good idea. DASH7

capabilities of transmission over

metallic obstacles, together with

multi‐year battery‐life seem

promising as the next‐generation

automotive wireless systems. An

example of it is the tire pressure

monitoring system. DASH7‐based

TPMS will provide more accurate tire

pressure readings, resulting in

greater fuel economy, reduced tire

wear and tear, and greater safety.

Logistics

Food retailers are focusing on

improving the cold‐chain by making

sure the product quality is good at

the end‐point with the help of

sensors.

RFID tags used today for such things

are passive devices. Dash7 tags are

active, meaning that they make use

of small batteries instead. Projects

such as “The Intelligent Container”

developed in the University of

Bremen

(http://www.intelligentcontainer.co

m) are using wireless sensor

networks in the interior of

containers to monitor temperature

and other environmental factors

that can impact the integrity of

sensitive products. Wave

propagation through paths with high

humidity and water‐rich goods has

been shown to be an important

factor. Dash 7 excellent propagation

through water is being adopted as a

solution to this problem.

Dash 7 will assist logistics providing

businesses with unprecedented

visibility into their everyday

operations.

Building Automation and Smart

energy

DASH7's signal propagation

characteristics, that allow it to

penetrate walls, windows and doors,

make it the best wireless‐based

technology for this purpose.


23

Additionally, the low current draw of

Dash7‐enabled devices makes them

suitable to harvest energy from the

environment easily. A sensor may

take the required energy from the

sun or from the power wire; shades

of Nikola Tesla!

Dash7‐enabled in‐home devices can

be integrated with lighting, HVAC

control devices, alarm systems,

curtain controls, etc.. Smart power

consumption and water meters can

communicate with gateways and

react to improve facility

management resulting in reduced

maintenance and human resource

costs.

About the author:

Javier Palafox has a Master of Science degree in information and automation engineering from

the University of Bremen. Previously, he has earned several years of industry experience working

in industrial automation. Currently, he is pursuing a PhD in the Institute for Microsensors, ‐

actuators and ‐systems (IMSAS).His research interests include intelligent and energy‐efficient data

processing algorithms on sensor nodes. In addition, he is very interested in DASH7 energy‐

harvesting and high transmission range capabilities.


24

Opportunistic Infrastructure‐Based

DASH7 Mode 2 Localization

Weyn Maarten and Dennis Laurijssen, Christoph Plas, Dragan Subotic

e‐Lab, Artesis University College of Antwerp, Belgium

The e‐Lab research group Artesis University College, working on Ambient Intelligence, has been focusing on localization technologies and algorithms during the last six years.

Every technique and technology used for localization has its own specific properties and advantages, but also its specific disadvantages. One of the common disadvantages of many existing localization systems is the need for dedicated devices and proprietary infrastructure. Multi‐modal systems which use the data coming from different systems and sensors will be the only possibility to allow affordable localization in different situations.

The future of localization systems

will most likely evolve towards

systems that can adapt and cope

with any available information

provided by mobile clients without

the need to install any additional

dedicated infrastructure. This type

of localization is called opportunistic

localization. It is defined as: "An

opportunistic localization system is a

system, which seizes the opportunity

and takes advantage of any readily

available location related

information in an environment,

network and mobile device for the

estimation of the mobile device

absolute or relative position without

relying on the installation of any

dedicated localization hardware

infrastructure."

In the past, the seamless


25

combination of Wi‐Fi, GPS, Bluetooth and cellular data with

inertial sensori and afterwards

Zigbeeii has been examined.

Although the opportunistic integration of these technologies does enable a lot of applications and services, some other applications are still not feasible. These limitations can be caused by the technical capabilities of the technology or the related cost.

The quest for … Dash7

Three applications, coming from partnering companies, led to the search for another technology. The first one was flow monitoring of people in an office building (who is sitting on which desk). They required a system which could be set up in one day, monitor for another day and be broken down in a few hours. On top of this the cost should be minimal.

After this request, the quest for a matching technology started. Wi‐Fi was not ideal, since you need the infrastructure, and if it is already there you need to interact with it. Moreover Wi‐Fi tags still cost more than €40. RFID based solutions mostly need wired readers, which are also costly if you need a lot of them (in order to be able to differentiate every desk). A logical direction was to look for a Wireless Sensor Network solution. But most Zigbee modules still range around €10 and you have to cope with closed stacks. These closed stacks do not always allow signal strength measurement between devices. These measurements are a necessity in order to enable signal strength based localization.

And then, there was Dash7! More specifically Dash7 Mode 2. The use of e.g. TI’s CC430 enabled the creation of < €15 modules. D7M2 is made for ultra‐low power RF communication, for localization we are only interested in regular signal strength measurements. The different device classes (blinker, endnode, subcontroler, gateway), perfectly match the different types of devices which are needed for localization.

The low cost, very small footprint, low power consumption and a communication range with a


26

theoretical maximum of 10km are features which could bring us a step closer to realizing the concept of the “Internet of Things”.

People motion monitoring

A second application was the tracking of people and shopping carts in malls.

Currently the motion tracking of people is already being monitored by for example Bluetooth; this gives a sample size of about 15% of the people, since only a limited amount of people are wearing a devices with active Bluetooth. A probably easier method is to track the shopping carts or shopping baskets. But this can only be done by using ultra‐low power tags with a very low cost. The use of passive RFID asks for expensive readers. Again here, Dash7 could be the solution.

Small animals, small tags

The third application was the tracking of very small birds (tomtits).

There, average weight is only 20 gram and the weight of a tracking device can only be 5% of their weight.

Currently, expensive VHF transmitters are used, which enables manual tracking for about a month. Ideally the researchers want to track the birds during their whole existence. The ultimate goal of the research of Dash7 at Artesis is to enable this localization using D7M2. The same hardware can afterwards be used to make small, easy integratable localization tags for other applications.

From questions to answers

To enable three of the above mentioned applications, 3 signal strength based localization methods are being investigated.

The mobile node is a blinker node, with a time interval set depending on the application, ranging from every second, to a few times a day.

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29

DASH7 UWG families…

e‐Lab, Artesis University College of Antwerp, Belgium

Focusing on Ambient Intelligent and context awareness the e‐Lab group of the Artesis University College of Antwerp, Belgium, continually strives to extend its knowledge in related technologies. Dr. Maarten Weyn has been working on localization algorithms and the seamless combination of different technologies during the past years.

From left: Plas, Weyn, Laurijssen, Subotic

Dash 7 Mode 2 can enable some applications where other technologies had difficulties in providing an affordable solution. Currently, the research in the e‐Lab on Dash 7 is being executed by Maarten Weyn and two master students Dennis Laurijssen and Christophe Plas. This group has recently been extended by Dragan Subotic who will be working on Dash 7 for the next year.

To ensure some funding for this research a national IWT innovation project together with our spin‐off AtSharp is currently being submitted for review, as well as a PhD project on the miniaturization of self‐sustainable localization tags.

More information: [email protected]


30

DASH7 UWG families…

Embedded Network Systems Lab, PNU, South Korea

ENS Lab was founded in 1994 and is led by professor Sang‐Hwa Chung. ENS Lab is in Computer Engineering Department at the Pusan National University in Busan, South Korea. Presently, there are 5 PhD students and 9 Master students. And, to‐date 6 PhD and 40 masters degrees have been awarded.

This research laboratory studies a wide range of issues in the aspects of embedded systems and networking. ENS Lab’s current research is as follows:

Dash : Development of Dash7 tags and readers with OpenTag

Active RFID: Development of global logistics information synchronization technology and CSD(Container Security Device)

WLAN Mesh Network: Development of Mesh network based on IEEE 802.11a/b/g/n

Prof. Sang‐Hwa Chung

Sang‐Hwa Chung received the BSc degree in electrical engineering from Seoul National University in 1985, the MSc degree in computer engineering from Iowa State University in 1988, and the PhD degree in computer engineering from the University of Southern California in 1993. He was an Assistant Professor in the Electrical and Computer Engineering Department at the University of Central Florida from 1993 to 1994. He is currently a professor in the Computer Engineering Department at Pusan National University, South Korea. His research interests are in the areas of Dash7, Active RFID, and embedded wireless networking.


31

Get in touch with UWG

UWG offers many advantages for you as an academic. Above all, it provides you

with the opportunity to collaborate with academics with vested interest in

DASH7, coming from different backgrounds of research and geographies. UWG

members are involved in collaborative DASH7 research projects…and young

researchers have the opportunity of finding internships among UWG universities,

too.

The best way to contact us is email. If you have questions, just drop an email to

one of the co‐chairs of UWG:

Chanaka Lloyd Pere Tuset [email protected]

[email protected]

You can register yourself as UWG (also known as URP – University relations

Program) member in the DASH7 homepage. Follow the steps below:

http://www.dash7.org/ > About the Alliance > University Relations Program

Join DASH7Join UWGJoin the research

DASH7 Alliance, Inc.275 Tennant Avenue

Morgan Hill, CA 95037Phone: +1 408 778 8372

Editors:Chanaka LloydPere Tuset

Designer: Zuolin Xu

dash7 alliance university working group magazine - may 2012

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