QUARTER 2 2007
www.nordicsemi.no
THE WIRELESS QUARTER
p FRWD Technologies
computer targets
outdoor enthusiasts
u nRF24AP1 ready for
network challenge
p Adding wireless to
portable devices has
never been easier
u Nordic in the press
p People & faces
REMOTE CONTROL
Controller navigates iPod’s stored
content from up to 30 metres away
}
Swiss consumer electronics
specialist Zicplay has specified
a pair of nRF24L01 transceivers
for each of its shirt pocket-sized
EWOO™ iPod™ wireless remote
control and docking stations.
The controllers feature a large
1.8-inch colour LCD screen,
intuitive circular navigation scroll
wheel, and enable full iTunes™
wireless navigation of both music
and video content from up to 30
metres away. This includes access
to menu, song, artist and playlist
functionality and organisation
employed on the iPod itself.
The EWOO is supplied in two
parts – a dock that can house
and charge both the EWOO and
any iPod with a Dock Connector,
plus the actual 60 gram remote
controller. An optional USB dongle
further allows users to remotely
control the iTunes library located
on their Mac or PC. At the back of
the dock are analogue and digital
(optical) audio – plus video (S-video)
– line outs designed for users to
connect to their home audio-visual
equipment and/or computer.
The wireless control of each
EWOO is based on a matched
pair of Nordic nRF24L01 2 Mbit/s,
2.4 GHz transceivers – one in the
remote and one in the iPod docking
unit. These underpin the two-way
radio comms required to access
content in an iTunes library such
as ‘live’ song play information.
The nRF24L01 transceivers
provide excellent co-existence
performance with other 2.4 GHz
systems such as Wi-Fi, Bluetooth
and cordless phones. In addition,
the ultra-low power characteristics
of the nRF24L01 mean under
normal use (45 minutes active
navigation per day) the EWOO
offers around 10 days of battery life
before its built-in polymer lithium
battery cells need to be recharged.
“Although we did consider using
standard 2.4 GHz technologies
– including Bluetooth, ZigBee and
Wi-Fi – none matched Nordic’s
proprietary solution for power
consumption, bandwidth and
overall implementation cost,” says
Alexandre Colot, Chief Technical
Officer at Zicplay. “The nRF24L01
consumes about three times less
power than that consumed by
the ‘low power’ LCD screen in our
application and the nRF24L01 also
absorbs so much of the RF design
complexity that it requires only a
low cost 8-bit microcontroller to
support it. This has all helped us
to build a high value handset that
weighs just 60 grams [by using
small batteries] – about the same
weight as a chicken’s egg – yet will
typically run for around 10 days
between recharges.”
“The nRF24L01 transceivers provide the EWOO with a
robust 30 metre wireless link even when obstructions are
in the way or if the user moves to an adjacent room”
WELCOME TO THE WIRELESS QUARTER
This is the fourth issue of Nordic’s quarterly newsletter. It is designed to keep you updated on the latest news and
developments at Nordic and is supplied free-of-charge.
PLEASE FORWARD THIS NEWSLETTER TO ANY COLLEAGUES OR CUSTOMERS WHO MAY FIND IT USEFUL
To subscribe (or un-subscribe) please e-mail: [email protected]
iPod™ and iTunes™ are registered trademarks of Apple Inc.
In this issue
www.nordicsemi.no
ANT UPDATE
“We’ve seen an
accelerated adoption
of our 2.4 GHz
technologies in the
various segments of
the ultra-low power
wireless category
that Nordic leads”
Svenn-Tore Larsen
Dear Reader,
I am delighted to welcome you to the latest issue of Nordic
Semiconductor’s quarterly newsletter.
The company has just completed its 2006 annual report and I’m
pleased to say that over the past 12 months we have seen a significant
acceleration in the adoption rate of our 2.4 GHz technologies in the
various market segments that comprise the ultra-low power wireless
category. This is a category that Nordic has worked hard to create and
define, as well as establish itself as the global leader. The category’s
defining characteristics include one-year battery lifetimes from small
batteries (AA, AAA and coin cell) in 10 metre range wireless products.
Examples include both new and 27 MHz replacement business for
wireless keyboards and mice, from flagship multimedia products to
simpler, low cost Chinese developed 27 MHz alternatives. Indeed, Nordic
transceivers are now to be found within wireless keyboard and mice
products from almost all of the world’s leading vendors. (Page 3 of this
issue includes the latest update from Fujitsu Siemens Computers.)
Other booming segments within the ultra-low power wireless
category include sportswatch computers, health and wellness devices,
lifestyle products and industrial monitoring. In fact Nordic’s technology
is being designed into so many new products that we plan to increase
the number of pages in the Wireless Quarter to accommodate them.
As we look forward to 2007 you can expect to see a series of major
new product launches from Nordic. Our next generation of ultra-low
power transceivers, however, will include more than just radios. Our
proprietary devices will contain several additional vital functions that
modern ultra-low power applications require in order to deliver even
greater end-value to our customers and in turn their end users.
To support such developments, Nordic has increased its proportion of
software engineers during 2006 and has developed hardware solution
platforms that can be configured for optimum niche products in several
different segments with the help of software. To date this includes the
nRD24H1 two-way RF remote controller and nRD24V1 wireless VoIP
headset reference design platforms that were featured on pages 4 and 5
of the previous Q1 07 issue of the Wireless Quarter.
As such, Nordic’s leading position within the ultra-low power wireless
category has never been stronger and more consolidated. And for that I
must again extend gratitude to the continued support of our customers
without whom none of this would be possible.
Yours sincerely,
Svenn-Tore Larsen
Chief Executive Officer
2 NORDIC WIRELESS QUARTER Q2 2007
nRF24AP1 and ANT ready for
Wireless Sensor Network challenge
By Brian Macdonald, Director ANT
}
In the last issue of The Wireless Quarter we described how the
compelling combination of Nordic Semiconductor’s nRF24AP1 and
the ANT protocol has proved a great success with companies looking to
add 2.4 GHz wireless networking capabilities to their products, notably
to date in a range of current sport and health monitoring products.
However, greater successes are yet to come because the nRF24AP1
and ANT are also the ideal solution for the burgeoning Wireless Sensor
Network (WSN) sector. This sector is in its infancy, but analysts are
predicting enormous growth over the next decade. To be competitive
with traditional wired systems, WSNs – such as automated light and
heat control networks – must be very reliable, feature ultra-low power
consumption (because many of the network nodes have to be batterypowered and will often be hard to access) and above all, cheap to
purchase, install and maintain.
To meet these constraints, the radio must be engineered to spend
most of its time in an ultra-low power sleep mode (consuming just
microamps), wake up quickly, transmit for the shortest possible time
(because consumption rises to tens of milliamps during transmission)
and then quickly go back to sleep. The protocol is critical in ensuring the
radio operates with these ultra-low power consumption characteristics.
Average power consumption for a typical WSN node is in the microamp
range when employing the nRF24AP1 and ANT.
The main competition comes from a protocol based on a standard
ratified by the US-based IEEE (ZigBee 802.14.4). The backers of this
standard suggest that they have a modest sized protocol stack.
But in truth, this protocol is still relatively complex, weighing in
at no less than an order of magnitude larger than ANT. This increases
the microcontroller burden compared with ANT, demanding
microcontrollers that are more powerful and pushing up system cost by
60 percent. ANT requires just 2 to 4 kByte of host microcontroller system
resources compared to 32 kByte for the IEEE standard solution.
In operation, the nRF24AP1 and ANT’s ultra-low power consumption
makes the competition look distinctly power hungry. In similar
applications with similar usage patterns, Nordic transceivers using coin
cell-type batteries can extend battery life up to ten years compared to
just four months for the IEEE standard solution.
Fortunately, design engineers look beyond the marketing hype; as
Thomas Embla Bonnerud, Product Manager Standard Components with
Nordic puts it: “Designers have been quick to recognise that the protocol
is the critical component ensuring their Wireless Sensor Network
solution is fast to market, on budget and operates reliably within
exacting power constraints.”
The designers’ ability to carefully consider the specs puts Nordic
Semiconductor and ANT in a leading position to be the natural choice
for the highly efficient radios crucial to the success of the forthcoming
generation of WSNs.
NEWS
SPORTS INSTRUMENTS
IN BRIEF
1. Note: Figures based on room temperature measurements – in extreme hot or cold environments actual performance may vary.
FRWD Technologies computer targets
demanding outdoor sports enthusiasts
}
Finnish Outdoors Sports
Computer specialist, FRWD
Technologies, has placed the
nRF2401A and nRF24E1 2.4 GHz
transceivers at the heart of its W
Series wristwatch display-based GPS
intelligent sports computer.
The instrument, which displays
live training data and stores it for
later analysis, is targeted primarily
at demanding outdoor sports.
The W Series instruments come
in two versions – the W100 and
W600 – and combine GPS route,
speed and distance tracking
(accurate to ±3 metres 90 percent
of the time), a sea level referenced
altimeter and barometer (air
pressure), wireless heart rate
monitoring (W600 only, to ±1 bpm
accuracy) and 3-D post training or
event route-performance analysis.
The W100 comprises FRWD
recorder unit (weighing just 85
grams incl. 3 x AAA NiMH batteries)
with 16 MByte Flash memory, 50
gram wrist display (that boasts a
“Training Effect” feature to quantify
the impact exercise is having on
the user), armstrap, FRWD Replayer
Pro PC software and manuals (on
CD), plus a USB wireless dongle.
In addition, the W600 includes
Wireless utility meters are
smart and automated
a heart rate monitor chest strap
with AAA battery recharger. The
Replayer software allows users to
re-live a race or even compare their
performance to that of a friend in a
virtual simulation.
A Nordic nRF2401A transceiver
is used within the W Series PC
wireless dongle and wristwatch
display, and an nRF24E1 within the
recorder unit. Under continuous
usage conditions, the recorder
unit operates for around 12 hours
in Outdoor mode (GPS enabled)
and 24 hours in Indoor mode (GPS
turned off) from a 3 x AAA 1.5-V
battery source. The wristwatch
display will operate for around one
year in normal Watch mode or 500
hours in continuous measurement
mode (RF comms always on) from a
CR2032 (3 V lithium coin cell)1.
In operation, the recorder and
wristwatch display automatically
pair wirelessly at the touch of a
button. “We selected the Nordic
nRF24xxx transceivers because
you just could not do coin cell
wireless using standard wireless
solutions like Bluetooth,”
explains Ville Kampman, CTO of
FRWD Technologies. “And other
proprietary wireless vendors
couldn’t match the nRF24xxx’s
performance or Nordic’s design
expertise.”
Energy metering specialist
Landis+Gyr Enermet has specified
nRF24L01 transceivers to provide
automated, wireless connectivity
between its latest Enermet
E120Gi GPRS and Enermet E120i
smart utility meters. These allow
energy providers to wirelessly
collect consumption data via local
RF connectivity and GPRS. This
improves cost efficiency, while
giving domestic end users better
visibility of energy consumption.
Development kit targets
surveillance and control
KEYBOARD AND MOUSE
Finnish university startup Atific is
employing four 2.4 GHz nRF2401A
transceivers in its “Helicopter” multiradio Wireless Sensor Network (WSN)
development kit platforms (full size
image on page 5 of this issue). The
platforms are designed to act as nodes
for the development of wireless sensor
mesh networks. Prime application
targets include demanding indoor
surveillance and control where
security, network throughput and
robust interference resistance are of
paramount importance.
Wireless keyboard and laser mouse offer robust link
Skype phone chipsets
optimised for nRF24L01
}
Leading European IT provider
Fujitsu Siemens Computers is
using a set of three nRF24L01 2.4
GHz transceivers to provide the RF
link in its LX850 wireless keyboard
and laser mouse that – because no
driver is necessary – can connect to
almost any PC with a
USB interface.
Communicating
via a USB stick
connected to the user’s PC, the
nRF24L01 transceivers endow the
LX850 with a range of at least 10
metres and provide a reliable link
even when obstructions such as
people, desks and chairs are located
between the keyboard, mouse and
USB stick. This allows multiple
LX850 units to be used in close
proximity in busy environments
such as offices and makes the
product virtually immune to
interference from other 2.4
GHz technologies
such as
Wireless
Local
Area Networks (WLANs) and
Personal Area Networks (PANs).
Keyboard battery life is one
year or more from a pair of AAA
1.5 V cells and the mouse features
a rechargeable double AA 1.5 V
NiMH battery pack that lasts three
months between recharges.
The LX850 wireless keyboard
comes in an attractive, slim blacksilver coloured design with soft
touch keys and includes additional
multifunctional buttons to provide
fast access to favourite applications.
The LX850 laser mouse includes six
user-assignable mouse buttons plus
a four-way “Tilt Wheel” function.
Taiwan’s Holtek Semiconductor has
developed a pair of microcontrollerbased wireless Skype™ phone
controller chipsets that include
– and are optimised for – Nordic’s
2.4 GHz nRF24L01 transceivers.
These endow Holtek’s HT82A850/1R
chipset-based Skype handsets (or
other applications such as toys and
PC wireless comms) with a range of
at least 10 m and robust interference
resistance. Also, as the HT82A851R is
pre-certified to the USB Audio Device
Class, no additional software drivers
are needed. This means users can
plug their Skype phone into almost
any PC USB port and it will work.
NORDIC WIRELESS QUARTER Q2 2007 3
www.nordicsemi.no
WIRELESS DESIGN
Simplifying wireless design for portables
Nordic Semiconductor’s ultra-low power transceivers and custom protocols are the
ideal solution for easing the challenge of adding wireless links to portable devices
M
any designers are wary of
adding wireless connectivity
to their products because they
perceive it to be complex.
After all, silicon radios feature RF,
analogue and digital functions and
are complicated products. However,
most silicon radio vendors have
produced integrated transceivers
that make the process somewhat
easier. But it’s still not just a
case of dropping a chipset
onto the PCB; the designer
still has to be aware of all
the issues that will affect the
performance of their design.
The first step is to decide on
what wireless capability the
product needs. Over specifying
costs money and battery power,
and adds complexity. For example,
most portable wireless links only
need to operate over a few metres,
so it is unwise to use a chip that can
operate at up to tens of metres as that
increases cost and power consumption.
It also pays to accurately determine the
bandwidth requirements – if bandwidth
isn’t needed, it shouldn’t be specified.
The designer is also under pressure to
shrink the electronics to fit the compact
profile demanded by consumers of mobile
devices. That means that there just isn’t the
space to add big transceivers and peripheral
components onto an already crowded PCB.
While most silicon radio vendors have
done a good job of integration, the chips
typically demand some form of supervisory
microcontroller and an array of support
components. Nordic helps the designer
resolve the space constraints by offering
variants of its 2.4 GHz transceivers – such as
the nRF24E1 and nRF24E2 – with integrated
microcontroller.
Portable devices must be independent
of mains power and therefore draw
their power from batteries. The designer
faces a tough challenge working within
the constraints of this modest power
4 NORDIC WIRELESS QUARTER Q2 2007
Importance of protocol
Nordic’s ultra-low power transceivers are the
ideal solution for coin-cell powered devices
such as sports watches communicating with
heart rate monitors
budget. If the product features a powerful
microprocessor and a backlit screen, for
instance, then 50 to 60 percent of the
battery power has already been allocated.
Yet, consumers want mobile phones and
MP3 players with batteries that last for as
long as possible (at least tens of hours on a
single charge). To achieve this any wireless
connectivity has to be very efficient to
minimise its load on the batteries.
Nordic Semiconductor’s chips have
been specifically designed to run at ultralow power and typically exhibit at least
twice the battery life compared with
competing 2.4 GHz technologies – such as
The efficiency of the radio’s
protocol is measured by the
ratio of overhead to payload
(i.e. useful data). When
combined with the radio’s
bandwidth, this largely
determines the battery life of
the transceiver.
Bluetooth 1.2, for example,
typically uses a 160-bit packet
(other packet sizes are possible),
of which only 32 bits are the
data payload, with the overhead
of 128 bits comprising access codes
and headers, primarily to ensure
interoperability. That’s an efficiency
of 20 percent. To transmit exactly the
same amount of data a ZigBee device
would use a packet of 152 bits (again, other
packet sizes are feasible), with an efficiency
of 21 percent.
Compare this to Nordic’s nRF24L01, for
example, which is specifically designed
for ultra-low power consumption: It uses
lightweight protocols customised to the
application. In one example, the protocol
uses an 80-bit packet with an overhead
of 48 bits and a payload of 32 bits – that’s
an efficiency of 40 percent. In other
words, the device requires half as many
packets as Bluetooth to transmit the same
information, halving the device’s power
consumption (or alternatively, doubling
its bandwidth for useful data for the same
power consumption).
Engineered for ultra-low power
Transmission rapidly consumes battery
power. The freedom to select a customised
protocol allows the designer to engineer
the radio to spend most of its time in an
ultra-low power sleep mode (consuming
PHOTO COURTESY OF FRWD TECHNOLOGIES
Integrated controller saves space
Bluetooth – in an identical application,
while providing the same bandwidth
and range. Nordic’s chips also
outperform ZigBee on power
consumption while offering
superior bandwidth and a
lower price.
TECHNICAL BRIEFING
mouse communicating with a PC, Nordic
Semiconductor’s transceivers are an
excellent alternative.
Moreover, technology based on
standards has other disadvantages.
First, competitors have easy access to the
same technology, making it difficult to
differentiate the product in a fiercely
competitive global market. Second, to
employ the standard you have to meet the
standard – and that commits the designer
to costly non-recurring engineering (NRE)
charges in initial design and testing for
interoperability. Finally, by their very
nature, standards have to be a ‘one-sizefits-all’ solution offering little opportunity
for design flexibility. For example,
there are limits to how much the power
consumption can be reduced and the
bandwidth boosted in an RF product.
Nordic’s
transceivers
are integrated
and compact,
relatively simple
to design-in,
use an efficient
protocol, are
extremely power
frugal and
feature adaptive
frequency
hopping
PHOTO COURTESY OF ATIFIC
The ideal solution for reliable
communications
“Nordic Semiconductor’s chips have been specifically designed to run
at ultra-low power and typically exhibit at least twice the battery life
compared with competing 2.4 GHz technologies”
just microamps), wake up quickly,
transmit for the shortest possible time
(as consumption then rises to tens of
milliamps) and then go back to sleep fast.
Bluetooth and ZigBee can’t match this
ultra-low power performance because the
protocol is strictly defined by the standard
(although certain “profiles” can be
added for specific applications) to ensure
interoperability. The designer is therefore
unable to ‘tune’ the protocol to allow the
Bluetooth or ZigBee radio to enter an ultralow power sleep mode more quickly.
Bluetooth’s inefficient protocol stems
from the fact that it was designed to allow
users to connect several devices from
different manufacturers into a piconet. In
such a piconet (which can comprise up to
8 devices), each device is assigned a 48-bit
identity number. The first device identified
(usually within two seconds) becomes the
master, and sets the 1600 frequencies to be
used each second across the 2.4 GHz band.
All other devices in the piconet ‘lock’ or
synchronise to this sequence.
It doesn’t take much thought to realise
that most wireless applications only need
point-to-point communications rather
than a piconet. Nordic Semiconductor’s
transceivers can use custom protocols to
suit a specific application because they
don’t need to adhere to the Bluetooth
standard’s requirement to support a
piconet. (That doesn’t mean that Nordic’s
products can’t be used to form networks
– transceivers such as the nRF24AP1 can be
networked together to form many-noded
star, cluster and mesh topologies.)
Beyond the standard
For products that demand long battery life,
and reliable wireless communications with
low duty cycles, Nordic Semiconductor’s
transceivers are an ideal solution. There
are scores of applications where these
design criteria apply. Examples include
wireless games controllers and wireless
communication between a heart rate
sensor and sports computers.
Designers should also consider the
level of support they will get from the
supplier. They may need help with testing
or antenna positioning, for example.
Alternatively, if the PCB layout isn’t
optimised from an RF perspective, the
radio may be more prone to interference. If
the customer is buying from a distributor
they should make sure the provider
understands silicon radios – there’s much
more to it than just selling a chipset.
Nordic Semiconductor prides itself on
customer technical support. The company
employs many field applications engineers
who are expert in RF design and its
practical application.
Bluetooth and ZigBee demonstrate how
the electronics community can collaborate
to create operating standards that ensure
interoperability across global markets.
Both are excellent technologies that work
well in the defined sectors for which each
was originally designed. You only have to
attach a Bluetooth headset to your mobile
phone to experience this very practical RF
technique in action and to appreciate its
benefits. But if a manufacturer is making
both ends of the link, for example, an
MP3 player streaming wireless audio to a
pair of wireless headphones or a wireless
NORDIC WIRELESS QUARTER Q2 2007 5
www.nordicsemi.no
ELECTRONICS WEEKLY
Svenn-Tore Larsen, CEO of Nordic Semiconductor was
interviewed by the UK’s leading electronics newspaper
Electronics Weekly. Here’s what Svenn-Tore had to say
Electronics Weekly: Will Wibree kill
Bluetooth?
Svenn-Tore Larsen: I can’t
conceive of any wireless
technology that’s going to
kill Bluetooth. Bluetooth
shipments are likely to
be 500 million this year
and may reach a billion
by 2008. I’d call that an
unassailable position.
But what Nokia and Nordic Semiconductor
have seen is that Bluetooth does have
weaknesses that prevent it ever being used
in applications with small batteries – like
the coin cell devices used in watches and
similar products – in its present form.
That’s Wibree’s niche, and the reason why
all the Wibree initiative members, some of
whom also make Bluetooth chips, are saying
it’s complementary. In fact, the group is
planning chips that integrate Bluetooth and
Wibree on the same die.
EW: Why do we want another low-power
wireless initiative?
STL: Because we need it. There are plenty
of low power proprietary radios out there,
including ours, but we’re all pulling in
different directions. We’re fragmenting
the market instead of growing it. ZigBee
is OK for what it offers but is far from a
universal low power solution, and doesn’t
suit consumer applications. We need to
learn from the success of Bluetooth and
come up with an interoperable solution
that, ideally, links back to Bluetooth
devices but can run for months or years on
small batteries. There are plenty of people
saying it’s a waste of time, but that’s what a
lot of people also said about the Internet in
its early days.
EW: Is the market for Wibree really there?
STL: Nordic Semiconductor and others have
carved a pretty good niche selling silicon
radios into applications such as wireless
mice, health sensors, sports sensors and
the like. That market is still in its infancy
but is growing rapidly. But once you’ve got
a really cheap way to add an interoperable
wireless link to anything that’s battery
powered the potential is huge. Designers
will come up with thousands of ways to use
that link, especially if the information can
be transmitted to a mobile phone and stored.
People who say there’s no market for Wibree
just aren’t thinking imaginatively enough.
EW: How will this affect your proprietary
wireless products?
STL: It’s inevitably going to affect that
business in the longer term. But our
penetration is such that we can grow the
proprietary business for years yet. But yes,
we’re taking a risk with Wibree. Nordic
Semiconductor’s technical expertise,
particularly at the physical layer, could
conceivably become available to everybody
via an open standard. Our confidence comes
from what’s happened with Bluetooth
– from where dozens of companies fighting
for market share when the standard was
first available, you’ve now got two or three
big suppliers reaping the rewards. When it
comes to Wibree we’ve got a huge
head start with design and
applications expertise,
customer relationships
and mature
Svenn-Tore Larsen: “When it comes to Wibree
we’ve got a huge head start with design and
applications expertise, customer relationships
and mature distribution”
6 NORDIC WIRELESS QUARTER Q2 2007
This article was
originally published
in the 10 January
2007 issue of
Electronics Weekly
(EW). EW is the UK’s
premier electronics
newspaper with a
registered circulation
of 26,700 qualified
subscribers
distribution. We’d have to go badly wrong
not to end up as one of the big suppliers
when the market shakes out.
EW: Where are the most clever applications
of your products coming from globally?
STL: Probably Asia, which is our largest
market. The engineers there have no
pre-conceived notions; so don’t just
automatically opt for Bluetooth when they
need a short-range wireless link. When
they see what they can do with an ultra-low
power link with decent bandwidth they get
really excited. Often it’s not so much the
way the link’s being used that’s innovative,
it’s the form factor. A tiny transceiver with
small batteries lets the designers come up
with devices that can be embedded virtually
invisibly. That said, Europe, especially
Scandinavia, and the US are both areas that
come up with great products. A personal
favourite is an alarm clock from an Austrian
company that uses a wireless link from
a transceiver worn on the user’s wrist to
monitor sleep phases and determine the
best time to wake the person up. But even
this is only the start.
One of Nokia’s objectives is for Wibree-enabled
devices to link wirelessly with handsets
PHOTO COURTESY OF NOKIA
Securing the future in
ultra-low power wireless
PRESS ARTICLES
NIKKEI ELECTRONICS ASIA
Proprietary alternative
for low-cost wireless
HO M E
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SITE M A P
HOME > Nikkei Electronics Asia > Issue >
SEARCH
Monthly Special:
Non-Standard Solutions as
Wireless Communications
Alternatives
for
Low-Cost
Nikkei Electronics Asia -- January 2007
Some would claim low-cost wireless is wrapped-up by Bluetooth and ZigBee, but look deeper and
one will find proprietary RF alternatives could be better suited for some of the manufacturers'
products.
Shortcomings of Standards
Bluetooth is ideal for widely compatible communications on a personal area network (PAN)
comprising various mobile devices; adhering to the standard does indeed eliminate much of the
design challenge. A standard design is assured that the device will communicate with another built
to the same standard and will have the desired range and data transfer rate. Similarly the ZigBee
standard excels for products used on networks comprising scores of nodes where infrequent, yet
reliable communications are needed, and batteries are expected to last for years.
'To Develop SoC Incorporating WLAN Capability,'
Renesas Invests in Key Stream
Hitachi's 1/10 Size Pressure Sensor LSI with
Stacked MEMS, CMOS Circuit Runs with 1/2
Power Consumption
Fujitsu Develops G-PON Transceiver Able to
Operate at -40 to +85 Degrees and Receive
Optical Signals with More Than 1000x Power
Indian Automotive Electronics Market Reflects
Burgeoning Indian Economy
KT, C-CUBE Consortium Complete IPTV Trial
Supported by NDS Solutions
Fujitsu Releases Optical Transceivers Capable of
GPON Transmission
However, adhering to these standards does come at a price: the silicon is relatively expensive, and
there is significant data packet overhead simply to ensure trouble-free communications between
NE Asia Online Part Search
radios from different manufacturers, which increases data transfer time and consumes power.
Furthermore, much of the design effort and testing for 802.15 solutions is needed to ensure
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compliance with the standards. This makes sense when ensuring interoperability between mobiles,
notebook PCs or wireless sensors from many manufacturers, but if the application is destined for a
one-to-one dedicated link such as wireless mouse to keyboard, it becomes an unnecessary expense.
Nordic’s nRF24xxx transceivers are a compelling
alternative to standards-based solutions for ultralow power wireless, says John Leonard
Y
ou could be forgiven for thinking
that low-cost wireless means IEEE
802 in its Bluetooth (IEEE 802.15)
and ZigBee (IEEE 802.15.4) guises.
But while they undoubtedly get most of the
publicity – both are backed by aggressive
Special Interest Groups comprising a who’s
who of electronics industry heavyweights
– they aren’t the only wireless games in town.
Let’s compare Bluetooth and ZigBee with
Nordic’s nRF24E1. The Bluetooth 1.2 protocol
allows data to be transferred between one
master and up to seven slaves (in a PAN
or “piconet”) at nominal rates of up to 1
Mbit/s. However, the actual data payload is
usually reduced due to the overhead of a
communications protocol defining the type
of each unit with address and other header
information to ensure compatibility with
other Bluetooth devices. In practice the data
rate would be closer to 720 kbit/s.
Slaves may also go into lower power
“sniff”, “hold” or “park” modes. In sniff
mode a device listens only periodically,
during specific sniff slots, but does retain
the synchronisation. Hold and park modes
require less power, but do mean the device
loses synchronisation for at least 1600 hops
and has to wait for a new link to be set up.
This can take several seconds.
The Bluetooth standard includes a
range of “profiles”. Because of commercial
pressures from members of the Bluetooth
SIG most profiles are suited to media and
file transfer applications on mobile phones.
Consequently, development using Bluetooth
profiles is not trivial for simpler applications.
ZigBee is developed for low power, low
data rate wireless monitoring and control
applications across a large number of
distributed nodes. The standard is defined by
IEEE 802.15.4 and is a simple data protocol
offering high reliability. This includes
acknowledgement of each transmission
burst. ZigBee doesn’t require Bluetooth’s
synchronisation, decreasing power
Bluetooth
The Bluetooth 1.2 protocol allows data to be transferred between one master and up to seven
clients (in a PAN or piconet) at nominal rates of up to 1Mbps. However, the actual data payload is
usually reduced due to the overhead of a communications protocol defining the type of each unit
with address and other header information to ensure compatibility with other Bluetooth devices. In
practice the data rate would be closer to 720kbps.
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Because Bluetooth operates on the same licence-free ISM band as other wireless technologies (for
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example Wi-Fi), interference can compromise data rates because corrupted packets need to be
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re-transmitted.
The devices in a Bluetooth piconet each have a unique 48-bit identity number. The first device
identified (usually within 2s) becomes the master, and sets the 1,600 frequencies to be used each
master transmits in even slots, the client responds in odd slots. Active client devices in the piconet
are assigned an address, and listen for slots addressed to themselves.
Clients may also go into lower power sniff, hold or park modes. In sniff mode a device listens only
periodically, during specific sniff slots, but does retain the synchronization. In hold, a device listens
only to determine if it should become active. In park, a device gives up its address. Although hold
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and park modes extend battery life, it does mean the device loses synchronization for at least 1,600
hops and has to wait for a new link to be set up. This can take several seconds and is a drawback
when the user requires a constant fast response.
ZigBee Limitations
ZigBee is a more recent RF standard specifically developed for low-power, low data rate wireless
monitoring and control applications across a large number of distributed nodes. The standard is
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second across the band. All other devices in the piconet lock or synchronize to this sequence. The
This article was
originally published in
the January 2007 issue
of Nikkei Electronics Asia
(NEA). NEA is a regional
edition of Nikkei
Electronics. NEA has a
registered circulation
of 26,943 qualified
subscribers in Hong
Kong, Taiwan, Korea,
Singapore, India and
Malaysia
������
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Figure 1: Interference between co-located wireless mice is limited because low RF output
restricts signal strength at co-located receiver
requirements considerably. ZigBee operates
in the ISM 2.4 GHz band (16 channels at 5
MHz spacing), but also supports European
868 MHz (single channel) and US 915 MHz
(10 channels spaced at 2 MHz) operation.
Maximum data rate is quoted at 250 kbit/s.
The proprietary advantage
Nordic’s nRF24E1 offers many advantages
over Bluetooth and ZigBee in terms of cost
and power. The nRF24E1 consumes 75
percent less power than a Bluetooth chip in a
comparable point-to-point application while
offering the same 1 Mbit/s bandwidth. The
chip is also considerably less expensive.
All three wireless technologies have
mechanisms to reduce interference.
Bluetooth uses a frequency-hopping spread
spectrum (FHSS) approach to ensure all 79,
1-MHz channels are covered equally over time
to avoid consistent channel interference.
ZigBee is geared more towards handling
intermittent narrowband interference with
the use of a direct sequence spread sprectrum
(DSSS) across its 16 bands, and so in the
presence of other 802.11b/g devices is more
prone to interference, and may have to wait
for the other device to stop transmitting.
Nordic’s device takes a hybrid approach.
To minimise current consumption and
complexity it does not use a spread spectrum
scheme, simply transmitting on a single
frequency until a packet corruption
threshold is reached if there is interference.
Channel relocation involves a simple,
single-Byte SPI instruction to the device.
The availability of 79 1-MHz channels also
allows one-time relocation away from the
other device’s transmission frequency for
static applications. For the wireless mouse,
the co-channel rejection is typically -6
dBm. Consequently, as long as the distance
from mouse (TX) to USB dongle (RX) is
half that from the interference source,
communication should be uninterrupted as
6 dB equals a doubling of ‘RF distance’ (fig.1).
TO SEE THE ORIGINAL ARTICLE GO TO: techon.nikkeibp.co.jp/article/HONSHI/20070103/126029
NORDIC WIRELESS QUARTER Q2 2007 7
www.nordicsemi.no
THE PEOPLE & FACES
Behind Nordic Semiconductor
Stein Ormholt
Distribution Asset Manager
“Distributors
are crucial to
the ongoing
success of Nordic’s
business and my
job is to make
them very much
part of Nordic’s
ongoing sales and
customer care
programmes”
Hi. My name is Stein Ormholt and as Nordic’s distribution
asset manager my job is to support and liaise with our
distribution partners on a global basis. This means that
although I am based in Oslo, I spend around 40 percent of
my time travelling.
I joined Nordic in February 2006 having spent the
previous 25 years working for a Norwegian distributor. This
gave me a deep insight into the distribution business that
has proved invaluable when building relationships with
Nordic’s distributors and understanding how they work and
the challenges they face.
Nordic’s distributors serve two key roles for the company.
The first role is to extend the sales reach and benefit of using
Nordic’s technology to every company around the world
– large and small, local and global. The second role is to
manage the allocation and shipment of Nordic components
to customers.
This means our distributors are crucial to the ongoing
success of our business. My job is therefore to make them
very much a part of Nordic’s ongoing sales and customer
care programmes.
This includes conducting continuous, ongoing reviews
to ensure our distributors have the right support from
us and the right commercial and technical resources in
place to serve Nordic’s end customers; preparing accurate
forecasting of future orders to ensure we always have
adequate allocation of parts and can ensure timely delivery
for both existing and new customer projects; and keeping
our distributors fully updated of the latest Nordic product
developments that may be relevant to customers.
One of the things I really like about my job is the variety of
projects and people I work with and the fact that although
I can plan most days, there is always the excitement of
handling something unexpected now and then. It keeps you
on your toes, if nothing else.
Outside of work I enjoy the usual Norwegian activities
– including snow boarding and skiing in the winter and
cycling outdoors in the summer with the occasional swim
in some of the many beautiful fjords we enjoy having near
Oslo. The amount of travel I do is also not an issue because
my son is now a fully grown 20-year old studying in Bergen
and my wife says she quite enjoys having some time away
from me. I dare not speak for myself, however!
Stein Ormholt
Markus Bakka Hjerto
Quality Engineer
“My job demands
extremely close
attention to detail
and refusing
to ever allow
anything to get in
the way of Nordic
achieving its
extremely strict
quality policy”
Hi. My name is Markus Bakka Hjerto and as a quality engineer
I am responsible for ensuring that Nordic’s work methods (the
formal name is “methodologies”) are optimised to ensure
component end quality.
This demands an extremely close attention to detail
and refusing to ever allow anything to get in they way of
the company achieving its extremely strict quality policy.
This includes – but is by no means limited to – continually
meeting the requirements of our ISO 9001: 2000
accreditation.
The reality is that any semiconductor company that even
hints it is capable of maintaining a 100 percent perfect
manufacturing and development process 365 days a year
without a single failure, will probably lie about other things
as well.
In the real world, manufacturing and development
processes have variations and it’s my job to closely monitor
these and to build methodologies and systems that can
either prevent – or detect and correct – errors before they are
allowed to grow into bigger problems down the line.
Moreover, if an error occurs, it’s my job to rapidly
track down the root cause and implement the necessary
preventative actions to ensure it doesn’t occur again. An
important aspect here, however, is to work proactively; always
searching for any weak points that may have been missed and
building solutions to problems that – if I do my job correctly
– will never actually have an opportunity to occur.
One of the things I really like about my job is being
entrusted with the space I need to focus on the important
challenges without unnecessary external interference. That
doesn’t mean I don’t enjoy working with other people – you
couldn’t do my job unless you positively thrived on working
with lots of different people across an entire organisation
– but it does mean I am left to get on with focusing on what’s
really important for the company and given the support I
need to do that.
Outside of work, I love listening to a huge variety of music
and watching movies that come from all over the world and
in particular discovering hidden ‘gems’ that have not been
given mainstream recognition. I also like cycling, playing
squash and Telemark skiing (or “free heel skiing” where the
skis have a binding that only connects the tip of the boot on
the ski to allow greater flexibility of movement).
Markus Bakka Hjerto
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