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Gigaset elements GmbH

Düsseldorf, 03.2013

Technical White Paper: Choosing DECT ULE for Gigaset elements products

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Disclaimer: This document is preliminary, subject to final graphical artwork and updates according to

Gigaset elements CI.

Abstract This whitepaper explains the reasons, why Gigaset has chosen DECT ULE as primary wireless technology for

the Gigaset elements product range, it discusses the currently available technologies, compares important

requirements and discusses honestly and obviously the advantages and disadvantages of the different

technologies. The objective of this whitepaper is not to discuss wireless technologies in general or to

belittle other technologies, it shall explain, how Gigaset came to the mentioned conclusion.

A summary table at the end of this whitepaper summarizes the discussions within this whitepaper.

Technology focused and Customer focused ............................................................................................ 1

Available technologies ............................................................................................................................. 2

Range and Home Coverage ...................................................................................................................... 7

Reliability and Interference .................................................................................................................... 12

Further technical requirements ............................................................................................................. 18

Gigaset expertise and partnering ........................................................................................................... 22

Summary Table ...................................................................................................................................... 24

Technology focused and Customer focused General discussions can be divided between technology-focused and customer-focused.

Technology focused discussions emphasize the comparison between technical data, engineering figures

and factsheets between different technologies. Many technical comparisons are tuned in that way, that

the preferred technology is promoted and the obvious disadvantages of competing technologies are

emphasized. These comparisons are therefore always challengeable, since in all cases the engineering

figures can be interpreted differently and assumptions can be taken in another way to emphasize the

preferred technology.

Whitepaper: Choosing DECT ULE for Gigaset elements products

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Gigaset puts the benefit, the satisfaction and the excitement of the end-customer into the focus of

Gigaset’s deliberations. Despite a few technology-agnostics end-customers, the customer does not care

about technology. Technology has to support the requirements of the customer. It should be invisible and

may surprise the customer by offering exceptionally good solutions for the customer’s demand.

This whitepaper follows this rule of putting the customer demand into the center of the discussions.

Available technologies A nearly unlimited amount of proprietary and semi-standardized wireless technologies exist within the field

of the short-range wireless connections, Gigaset has 20 years of experience with deployment of wireless

technologies into homes over the whole world.

For the deployment of a new kind of application and a real mass-market adoption it is significantly

important, that the underlying wireless technology does not generate risks on customer dissatisfaction or

customer complaints. This would endanger the deployment plans for a broad acceptance of new

sensor/actuator applications and corresponding services.

The following overview is one of numerous possibilities to cluster and compare the different technologies

for in-home use.

Shared frequency and global frequency ranges

Nearly all wireless technologies are operating in one of the

ISM (Industrial, Scientific and Medical) frequency bands, the

only exception is DECT, which is operating nearly worldwide

in an exclusive frequency band.

The ISM bands are regulated worldwide; the regulations are

summarized by the International Telecommunication Union

(ITU) within the ITU Radio Regulation 5.150. The allocation

of the ISM frequency-bands depends sometimes on the

region. For Home Networking technologies the frequency

ranges 868 MHz ISM band is valid in Region 1 and 3. In Region 2 devices have to operate in the 915 MHz

frequency band. The other relevant ISM frequency range is the 2,4 GHz and in the 433 MHz frequency

band.

Overview of technologies per frequency range

The figure below shows the frequency bands and the different technologies, which reside in these

frequency bands. The proliferation of different technologies sharing the ISM bands is obvious. This cannot

be stressed enough. Only the DECT technology with its derivates has a globally exclusive frequency band.

The technology names DECT, CAT-iq and ULE in the figure below are names for the same technology,

operating in different modes.

Figure 1: ITU regions concerning international frequency allocation (incl. ISM)


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Global Frequency Band

433MHz

868(EU)/915(US)MHz

1900MHz

2400MHz

DECT 2,4 GHz Cordless Phones

Microwave

Bluetooth

This is only an excerpt, there are many more suppliers !

Zaura

This is only an excerpt, there are many more suppliers !

Figure 2: Global overview of frequency bands and technologies

Technologies in 433 MHz ISM frequency band

This is the band where remote controls, car-keys, switchable power plugs and many similar wireless

applications reside, the technologies are optimized for cost and not reliability.

This band is already very crowded, and the figure above shows as an excerpt the following competitors,

offering modules and chips for this band: Dash 7 Alliance, Shenzhen Friendcom Technology Development

Co., Ltd, Reindeer Technologies Pvt. Ltd., HK Shan Hai Group Limited, Radiometrix, Shenzhen AND

Technologies Co. Ltd, Yancheng E&C Electronic Co., Ltd. Shenzhen Jizhuo Technology Co., Ltd., Shenzhen E-

Chips Technology Co., Ltd.

Worth mentioning is the Dash 7 Alliance, it is based on an order from U.S. Department of Defense to 4 US

companies for RFID-like sensors to control the worldwide logistics of the U.S. forces and their material all

over the world.

Technologies in 868/915 MHz ISM frequency band

This is also a free band, therefore multiple proprietary standards for all kind of cost effective wireless

applications, mainly remote controls Man-to-Machine or Machine-to Machine and sensor-networks are

already operating within this band.

As an excerpt, technologies from the following companies and alliances are shown in the figure above:

Wavenis Alliance (Coronis Systems), Wave2M Alliance, Z-Wave (Sigma Designs), EnOcean (EnOcean GmbH,

EnOcean Alliance), One-NET Open Source, KNX Alliance, TinyOne™ from Telit, RC1180 from Radiocrafts,

XBee®868 from Digi, TRM-868 from Linx Technologies, Zaura© from Zilog, Zigbee 868 Alliance, ME50-868

from Silicon Labs, AMB8420 from Amber Wireless, VT-CC1101PA-868 from V-chip Microsystems.Inc.


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Over the years a lot of different technologies from many competitors have been established to operate

within this band, for differentiation reasons those competitors have established different proprietary

operation techniques within the same band, today multiple products are on the market with different

approaches on making use of the band, empirical experience show, that with ongoing proliferation of

wireless applications within this band the risk increases, that the applications do not operate well within

this band.

To overcome this enormous variety there are several attempts to place an industry-standard or a de-facto

standardization, examples for this is the Wavenis Alliance, which became later the Wave2M Alliance, which

has been initially established by the company Coronis Systems. Another Alliance is the KNX standard in

868MHz which comes from the KNX Alliance, a Consortium from companies mainly from electrical switch

and control industry.

The company Zensys A/S has established the Z-Wave Initiative with the objective to better market their 868

MHz communication chipsets. In 2008 Zensys has been acquired by Sigma Designs, however Z-Wave is not

an open standard, it stays a proprietary technology owned by Sigma Designs and Sigma Designs sells the

chipsets and also licenses designs, stack software, and APIs to chip manufacturers.

New Consortia are continuously coming up like for example EnOcean Alliance, which has been established

in 2008 by EnOcean GmbH, a German spin-off from the company Siemens AG.

The DECT band 1880-1900 MHz

The DECT Technology (Digital Enhanced Communications Technology) has been developed and

standardized by the European Telecommunication Standardization Institute (ETSI), the band is regulated

and protected by national regulative authorities and adopted nearly worldwide.

This band is different from the ISM bands, since an etiquette1

The ETSI has developed two derivates of the technology, this is the CAT-iq technology, which defines a

certain set of mandatory protocol elements to enable interoperability between telephone sets from

different vendors and secondly ULE, which is optimized for sensor applications with battery lifetime of

multiple years, but there is no difference in the underlying etiquette on using the band, further industry

alliances are promoting these derivatives.

on how to use this band is defined and

therefore this band is worldwide exclusive for the DECT Technology.

Technologies in 2400 MHz ISM frequency band

This is the broadest ISM band and is therefore the only band, where broadband wireless technologies are

possible. As already mentioned the relevant technologies within this band are the Wi-Fi and the Bluetooth

technology, but since this band is a free ISM band, multiple technologies are operating in this band. An

excerpt of the technology providers within this band are shown within the figure above:

1 The word “etiquette” is used here to define a common method, how the corresponding frequency band is used. The etiquette defines a common behavior for the technical usage of the band and therefore reduces interference within that frequency band.


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Wi-Fi Alliance, Bluetooth SIG, Dynastream Innovations Inc, ZigBee Alliance, Laird Technologies, HART

Communications Foundation, Shenzhen Micreal Development Technology Limited, Shenzhen Jiachen

Technology Ltd., Xin Wei Heng Ye Electronics Technology Co., Ltd., JIEXING Weiye Electronic Co., Ltd,

Shenzhen Epona Tech Ltd.. Shenzhen Pengji Photoelectricity Ltd..

Examples for applications from the latter proprietary technology providers are 2,4GHz TV-to-TV or PC-to-TV

video-streaming applications.

Today the dominant technology within this band is the Wi-Fi technology, also called IEEE 802.11, since it

has been developed and standardized by the Institute of Electrical and Electronics Engineers (IEEE) and is

worldwide adopted. Later the Wi-Fi Alliance has established certain rules for this technology to enable

interoperability between devices from different vendors.

The second most relevant technology is the Bluetooth technology.

Microwave ovens also operate within this frequency band at a frequency of 2,45 GHz and this is NOT the

resonant frequency of a water molecule. The 2,45 GHz frequency is a compromise between penetrating

food and being absorbed by food. The RF-shielding of the microwaves is not 100%, so that a small amount

of leakage can disturb wireless communication nearby an operating microwave oven.

Established Mass Market technologies

The relevant technologies within this cluster are Wi-Fi, DECT and Bluetooth.

• Wi-Fi is established as “Internet-Access” technology, it is a so called “best effort data” technology

and mainly implemented in Internet Routers, portable computers and Smartphones with about 5

Billion Chipsets sold up to date.

Wi-Fi is based on the standard IEEE802.11, the initial base standard has been released in 1997.

Wi-Fi Low Power is a further development of the Wi-Fi technology with the focus on lower power

consumption and on new applications with longer battery lifetime.

• Bluetooth is established as “PAN (Personal Area Network)” technology and is mainly implemented

in Mobile Phones, Smartphones, wireless Headsets, Handsfree in Cars, and wireless Audio

Loudspeakers with about 10 Billion Chipsets sold up to date. The Bluetooth technology has been

created by Ericsson in 1994 and the Bluetooth SIG, a consortium from major global players in the

CE industry has developed the corresponding standard out of this, the initial release of the

standard was in 1999.

Bluetooth LE (Low Energy) is a further development of the Bluetooth Standard with the focus on

new applications with long battery lifetime.

• DECT is a established as generic access technology providing high-quality voice services, even

though it has been designed for data service also, it is today mainly implemented into Cordless

Phone Base Stations and Cordless Phones Terminals, wireless PABXes and Internet Routers with

about 2 Billion Chipsets sold up to date.

The ETSI has developed this standard, the initial base standard has been released in 1992.

DECT ULE (Ultra Low Energy) is a further development of the DECT Standard with the focus on new


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applications with long battery lifetime.

Network Topology:

The different technologies are designed for different network topologies, the discussion of these network

designs also shows the development history and the intended application fields of the technology. The

figure below shows 3 different network topologies. There are more than these 3 topologies, for example

the KNX and the KNX-RF technology uses a “star topology within a bus technology”, which is not discussed

here. All nodes of a KNX system are connected via a bus technology, KNX has been an established

technology for more than 15 years and is a consolidation of the 3 European home-network technologies

European Installation Bus (EIB), European Home System (EHS) and BatiBUS.

KNX is established within the electric installer market and less relevant for end-customer and thus not

relevant for Gigaset elements.

Coordinator Node/Router Node

Peer to Peer Mesh NetworkStar Network

Figure 3: Network topologies

Peer to Peer:

The Bluetooth technology is the most noted technology which uses this topology for data exchange

between mobile phones or for streaming voice or audio data from mobile phones or Smartphones to

Headsets, Car-Handsfree devices or to wireless audio equipment. The Bluetooth technical standard

describes more topologies like Scatternets, Piconets-cells and more. Furthermore Bluetooth is used for

further multiple applications, but by far the most popular applications uses peer-to peer topology.

Wi-Fi is also able to use Peer to Peer modes to exchange data between two notebooks or other devices,

but in reality most people do not know how to establish this mode and therefore this mode is less relevant.

Star Network

Wi-Fi and DECT are the most noted technologies which use the Star topology.

In Wi-Fi networks the Internet Router acts as the Coordinator and routes the connected devices - which can

be Smartphones, Notebooks or Wi-Fi modules - into the Internet.

In DECT networks the DECT Base Station acts as the coordinator and gives the connected devices access to

the network. Today this principle is followed by the DECT cordless telephone system, existing of a base

station and one or more cordless handsets, offering mainly telephony and also data services.


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All other technologies like ZigBee, Z-Wave, Wave2m, and Bluetooth are able to use this topology also. Here

it is often used to provide nodes access to the internet.

Mesh Network

Technologies like ZigBee, Z-Wave, and Wave2M are able to enable mesh networks, thus reflecting the

initial requirement to support battery-driven, wireless sensor fields for industrial use. Those technologies

are able to establish routings over different sensor nodes in the network. Mesh networks as with these

technologies reflect the vision that a comprehensive deployment of many sensors and actuators with this

technology is achieved within an industrial sensor field or within a home network.

Next to this initial requirement for mesh networking for industrial use this functionality is used as

argument to overcome range limitations because of link budget limitations, the argument is “when you do

not have the range you need, you can use additional routers within the network.”

Mesh network technologies have intelligent self-routing functionalities, but need some kind of network

planning or need a huge deployment of multiple sensors/actuators: Sensor/actuator nodes with routing

functionalities have to be placed at special places within the range of other devices, this hinders

deployments in a mass market, where the average customer is not interested in technological details.

Technology has to support the requirements of the customer. It should be invisible and may surprise the

customer by offering exceptionally good solutions for the customer’s demand.

Range and Home Coverage Range is one major criterion for the decision on a wireless technology. This reflects the end-user

requirement to easily place sensors and actuators within his home himself without the need to

troubleshoot or without the need to plan a sensor network.

Any home network technology must be capable of reliably transmitting over distances the size of a typical

house. The link budget is a relevant and accepted benchmark to compare wireless technologies. The link

budget is simply reflecting the power of a transmitter and the sensitivity of a receiver. The higher the link

budget is, the better the range of the technology.

Link budget can be explained using the example of human communication. If two humans want to

communicate over a distance, the range of this communication is dependent on how loud the one person

shouts (transmitter power) and how sensitive the other person can listen (receiver sensitivity). Since the

sensitivity of humans is somehow limited, the one person has to shout louder, to increase the range.


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In wireless technology the sensitivity is limited due to physical limitations and the transmitting power is

limited due to national regulations concerning frequency allocation and interference protections. Link

budgets are expressed in Decibel (dB).

If a technology has 6 dB less link budget than another, it means, that this technology offers only 1/2 of the

range and if a technology has 20 dB less link budget than another, it means, that this technology offers only

1/10 of the range.

In addition, the absolute Free Space Loss limits the range of a technology and depends on the operating

frequency. If a technology reaches 30 meter range at 1900 MHz frequency, it would reach with same

transmit power only 23 meter at 2400 MHz frequency, only because of free space loss within the higher

frequency!

The following table shows the Link Budget and free space loss of different technologies. The higher the Link

Budget, the better and the lower the Free Space Loss the better.

Example

Technology

Frequency Link Budget Free Space Loss @1m

Wave2M 868/915 MHz 121 dB 31,5 dB

ZigBee 2400 MHz 106 dB 40 dB

Bluetooth1) 2400 MHz 89 dB 40 dB

Z-Wave 868/915 MHz 101 dB 31,5 dB

DECT 1900 MHz 122 dB 38 dB

Wi-Fi BPSK 2400 MHz 115 dB 40 dB

Wi-Fi 64QAM2) 2400 MHz 86 dB 40 dB Table 1: Overview of Link Budgets of different technologies: 1) BT LE uses Class 3 or Class 2, class 2 has been considered 2): OFDM, CREST factor reduction (PA linearity requirements for OFDM) considered; 108 MB/s with MIMO technology

The Wi-Fi technology is represented over two lines. Wi-Fi is a high-bandwidth technology, but switches

dynamically down to low bandwidth, when Receiving Power or Quality of Service drops. The low bandwidth

mode would also be used to support sensors and the lines above reflect the daily experience with Wi-Fi in

homes today. When the range is extended, data throughput drops and even in the low bandwidth mode,

Wi-Fi has less than half of the range than DECT, in addition to the higher free-space loss.

Regarding a table like this, engineers can always and have always used the technical specification of a


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wireless standard to calculate possible ranges or theoretically reachable performances, but the only

decision basis to decide for a wireless technology for mass market use is the reality. Today many

measurements and practical experiences are available on the 3 established technologies Wi-Fi, DECT and

Bluetooth. A broad experience for the upcoming technologies like ZigBee, Z-Wave and Wave2M is not

available due to the fact, that these technologies have not yet had a breakthrough in the deployment for

mass market applications. It is furthermore questionable whether these technologies will reach a

breakthrough since multiple technologies compete on similar application fields within the same band.

This table confirms the daily experience in today’s homes: The only mature technology today, which is able

to cover a whole house is the DECT technology, hence the link budget of around 120 dB is required to

cover a home, theoretically also the emerging Wave2M is interesting if range would be the only decision

criteria.

Comparing to Wi-Fi

A new Wi-Fi standard 802.11n has been established in 2009 and is considered as the preferred mode for

Wi-Fi today with mode 802.11b and 802.11g as legacy. This technology claims to have better data

throughput than the earlier available standards 802.11b and 802.11g. Internet Routers with 802.11n can

also be re-configured in that way that range is improved instead of data throughput. Especially the range

topic has to be proven in reality within the coming years, and the fact has to be considered, that still many

802.11g and even 802.11b routers remain in the households for the next years. The Internet Routers with

802.11n are normally configured for improved data throughput. An 802.11n sensor network cannot rely,

that end-customers reconfigure their Internet Routers from optimum throughput to optimum range. Re-

configuring the Internet Router to improved range generates also a conflict at the end-customer with his

requirement to get highest possible data throughput.

The range problems of Wi-Fi in a household are less relevant with the current applications today, since Wi-

Fi is used to give internet access to Notebooks or Smartphones within the home. When the End-User

detects, that he is outside the Wi-Fi range, he improves his position within the house or simply moves

nearer to the Wi-Fi Internet Router.

With a sensor or actuator, this is not possible, since the position of this device is fixed and cannot be

changed.

Furthermore it is complicated and risky for the end-user to install a Wi-Fi sensor node at the range border.

It is a fact, that because of irregularity in propagation, diffraction, polarization, reflections and delay spread

it may be that a Wi-Fi sensor node is reachable at installation time, but is not always reachable after that.

Due to nature of an ISM band and validated by customer experience the environment of RF propagation

changes drastically as soon as a new application in the same band operate, as an example the 2,4 GHz

windows sensor might fail operating, when the customer installs a Wi-Fi video streaming application into

his living room or he buys a new TV set with Wi-Fi connection to the Internet.


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Comparing to Bluetooth

For the Bluetooth applications today range is less relevant, since the Bluetooth Headset is always near the

Bluetooth mobile phone, the Bluetooth Handsfree is always near the Bluetooth mobile phone, the

Bluetooth Loudspeaker Box is always near the Bluetooth media player.

Most Bluetooth chips today are “Class 2” Devices with an RF Transmitter Power of 4dBm. “Class 3” devices

are also available with 0dBm. Also the “Class 1” devices with 20dBm have been announced, but these

classes have not extensively been developed and are therefore not mature. Since the above mentioned,

relevant applications do not require these higher power. The Bluetooth LE technology supporting sensor

networks uses the 0 dBm class 3, many companies are developing new kind of applications using Bluetooth

LE and exciting applications in combination with a mobile phone as link to the Internet are being

developed, the range and power consumption is therefore optimized for low range connectivity and cannot

be used for stationary wireless sensors within the home.

Comparing to other technologies

Other 2,4 GHz technologies like for example ZigBee have a worse link budget and also a worse free space

loss, so it is obvious that other 2,4 GHz technologies are not able to cover a whole house.

Other 868/915 MHz technologies like for example Z-Wave or Wave 2M have a worse link budget, but a

better free space loss, long-year experiences and measurements as with DECT Cordless Phones do not exist

with these technologies, but it could be believed, that these technologies, dependant on their technology

implementation and RF performance could reach the range of a DECT device, therefore the range alone

might not be sufficient to support a decision for a technology.

Some technologies, for example the ZigBee technology claim, to overcome range limitations with their

ability, to form a “mesh network”, enabling these technologies to use mesh network elements (repeater

nodes) to extend the range of a sensor or actuator.

The figure below explains this approach.

An usual purchase of the end-customer is a sensor node [ND] for his Base Station [BS], which enables the

connection to the Internet. The curves in the figure represent schematically the ranges of the DECT and the

ZigBee technology, DECT with its Star-Network topology and with its range connects the node [ND] directly

via the Base Station [BS] to the Internet, while the ZigBee Base Station [BS] is not able to reach the node

[ND] directly. When the customer places a so called router node [RT], the base station can reach the node

[ND] by hopping via the router node [RT]. Router, node and base station form a mesh network.


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ZigBee Case DECT ULE Case

BS

RT

ND

BS

ND

Legend: BS: Base Station RT: Node/Router ND: Node

Figure 4: Increasing ZigBee range by a Router Node

From a technological point of view the ZigBee mesh method is acceptable, but it includes a risk since

this method is not at all proven in mass market deployments. This method of mesh networks are

acceptable for a deployment of a sensor network for example in a production plant, where you have a

team of engineers, who install, maintain and troubleshoot the sensor network.

Two further issues are worth considering, firstly the hot node through all the traffic may need to flow in

this mesh network and secondly it is unpredictable how messages are routed so latency can become

unpredictable.

For a mass market deployment with end-customers this is dangerous, since the end-user in the mass

market has no access to consulting technicians, and the setup of a supporting center would not result in a

positive business case for that business.

From a customer point of view the ZigBee mesh method is not applicable, since in this case the customer

has to - after having found that the sensor node [ND] does not work as expected, educate himself to find

that the range is not sufficient. The end-user then has to go back to the shop to purchase a new system

element, the Router [RT] and has to educate himself where to position the router within his home.

This means that the customer has to do a network planning, a method, which is done normally by

experienced technicians and the broad majority of the customers do simply not understand network

planning.

Gigaset experience from more than 30 years consumer electronic deployment in mass market is, that in the

above mentioned case the majority of customers simply put the products back into the packaging and

bring them back to the dealers for refund, complaining about the bad product and about the company

brand.

Most important is that the setup and installation of a sensor has to be “super easy” and “self explaining”,


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otherwise the average customer is over-challenged. This would certainly result in a failure of the system in

the market.

Reliability and Interference It bears repeating that the wireless interference

situation in homes cannot be emphasized enough,

if it would be possible to invent special spectacles,

which are able to visualize electromagnetic waves

in homes like in the figure on the right, we would

have more comprehension for this important fact.

Some can conceive the homes as a dense thicket

of electromagnetic waves, which come from

different sources, especially in the broad 2400

MHz frequency band devices like smartphones,

tablets, computers, play stations, and CE devices

proliferate homes with continuous communication

and the band is shared by different technologies,

the 868/915 MHz band has the issue, that it is very narrow and it is also shared by different technologies all

using the band in a different manner.

Additional wireless applications, especially Wi-Fi operating in the 2400 MHz area is coming into the homes

within newly purchased TV sets, Setup Boxes, AV Players, Streaming Devices, which cause instability to an

existing Wi-Fi network.

Due to nature of an ISM band the environment of RF propagation changes drastically as soon as a new

application in the same band operate, as an example the 2400 MHz windows sensor stops operating

reliably, as the customer installs a Wi-Fi video streaming application into his living room or he buys a new

TV set with Wi-Fi connection to the Internet.

The world is now at the starting point of sensor networks at home, with hundreds of millions of sensor

nodes up to billions of sensor nodes in the homes within the next decades. Therefore it makes sense to

decide for a technology that has proven maturity and offers problem-free communication.

For the increasing proliferation of wireless sensors and wireless technologies in future homes, flats and

apartments it is important to decide for an appropriate technology, which is able to support the

increasing high traffic densities and the continuous purchase of wireless applications by the customer.

These technical parameters are also one of the most important decision criteria for a technology decision.

It reflects the user experience with wireless devices that “sometimes the device does not work as

Figure 5: Example for real interference measurements for wireless devices (Source: Morrisville State College)


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expected”. Examples for this are:

• The RF remote control, which controls lights and shutter, does sometimes not switch on the light

or turn down the shutters. In reality this is less problematic, since if there is no action on key press,

the user presses the key again, sometimes changes his position and presses the key again.

• The Smartphone does not see the Wi-Fi Internet Router anymore or the Bluetooth mobile phone

does not see the wireless headset. Sometimes the wireless device does not find for whatever

reason the Wi-Fi Router or the peer device which usually always works, but not at the specific time.

In nearly all cases this is a temporary failure and the reason for the failure cannot be found in most

cases, in reality this is annoying, but it is less problematic, since for now the internet connection is

not available or the exchange of the phone number will be done later, in most times the

technology seems to work after some time again.

• There are some applications, where a wireless technology has to guarantee highest possible

reliability, for example, when the aged and infirm grandmother falls over, the appropriate sensor

must indicate this.

• When a wireless sensor detects a burglary, the wireless technology must indicate this to the

security provider.

Etiquette and Reliability of wireless communication

The topic “etiquette” is related, but different to the topic “interference” and is a widely underestimated,

but very important topic for wireless communication, especially since now the world starts into the era of

massive deployment of wireless sensors in hundreds of millions of homes, flats and apartments. Now the

industry needs to take the right decision for a wireless technology which can support the massive

deployment of wireless sensors in the homes and associated proliferation in the wireless frequency bands.

The figure below discusses this topic by using the comparison of a crowded road or motorway.


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868/915 MHzshared band

withoutcommon etiquette

DECT exclusive Band

with common etiquette

2400 MHz shared band

withoutcommon etiquette

Figure 6: Etiquette within a frequency band, explained using road comparison.

This figure shows different roads with cars, lorries and trucks from the aerial view.

This figure shows different roads, which are crowded, on these roads there are different cars, lorries and

trucks driving, the roads. Cars, lorries and trucks are shown from a aerial view.

The 868/915 MHz frequency band can be compared with the road on the left side of the figure, there

are multiple cars sharing this road and driving on this road. Some are driving faster, others are driving

slower, some drive in the opposite direction than the others, some cars suddenly take over, and other cars

continuously change lanes, other stay on the lanes. It is obvious, that when someone drives with a car on

this road, he cannot distinguish, whether he reaches his destination or whether the car crashes with other

cars. This allegory is very similar to the reality within this frequency band. Within the coming years, there is

no common etiquette within the band.

One application works, when there is only one technology operating in that band, but as soon as more

proprietary or semi-standardized technologies stuff this band in the near future, wireless communication

becomes uncertain in this band.

The 2400 MHz shared band can be compared with the road on the right side of the figure. The road is

broader, but multiple lorries and trucks stuff the road, some are bigger, others are less big,some use two

lines, other use one line, some drive faster, others drive less fast, suddenly new trucks appear on the road

(which is an allegory to the CSMA technique with Wi-Fi), some of the smaller cars continuously change

lanes or use other techniques to avoid collision with the big trucks and lorries.

This metaphor reflects the reality in a crowded 2400 MHz band, which is dominated by different WLAN

Radios, each sharing the same band and having only room for 3 (802.11b), 4(802.11g) or 2(802.11n)

carriers within that band, the same band is used for both uplink and for downlink of different WLAN


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radios and wireless payload packages, wanting to move into the street has problems to reach its

destination.

The DECT band can be compared with the road in the middle of the figure, since the band is exclusive for

DECT, all Cars follow the same etiquette, and the same rules apply for all cars, so every car can foresee the

behavior of the other cars. All cars have the same rules for changing the lanes, all cars are driving at the

same speed, and the road is like a motorway with a guardrail in the middle, so that cars driving into the one

direction (uplink) cannot collide with cars driving into the other direction (downlink).

This is similar to the reality in dense DECT environments, and the reason for this is also clear, since DECT

has been initially developed to provide high quality real-time communication in highly stuffed office

environment. Here very high density of traffic (measured in “Erlang”) is normal, DECT has been designed to

support a traffic density of up to 10.000 Erlang/km² (by way of comparison: GSM reaches 200 Erlang/km²).

One of the biggest advantages of the technology is the Dynamic Channel Selection, so no network

planning is required and the system re-organizes itself dynamically when the customer installs a new

application, reflecting the customer requirement that the system should simply work.

Interference issues in the 2400 MHz band

The 2400 MHz band has one major challenge, according to ABI Research and validated by other

researchers, the total Wi-Fi shipments reached 5 billion in 2012 and will ramp-up to total 20 Billion

shipments in 2017, this is understandable since also CE devices, which haven’t had Internet Access up to

now, like TV sets and others are going to implement Wi-Fi now.

This has major impact to this band, because of the dramatic proliferation of Wi-Fi signals the Quality of

Service of Wi-Fi operating applications will more often fail and other technologies operating within this

band will have huge problems on even interoperating within this band.

The figure to the right shows as an

example the frequency scheme of Wi-

Fi (U.S. version, IEEE 802.11b) and the

ZigBee frequency scheme. The ZigBee

channels are blue colored and the Wi-

Fi channels are indicated using the

semi-circles. It can be seen, that most

of the more narrow ZigBee channels

reside within the broader Wi-Fi channels, which means that ZigBee transmission and Wi-Fi transmission

might fail, when Wi-Fi is active in the same frequency area as ZigBee. ZigBee has several methods

implemented to avoid interference with Wi-Fi, for example detecting active Wi-Fi transmission, and moving

away from that area or using mesh network methods to avoid Wi-Fi collisions.

Figure 7: ZigBee and Wi-Fi Interference (Source: RTC Magazine)


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This works normally but it is a matter of fact, that on a regular basis collision cases occur so that data

transmission fails and has to be repeated or data could become lost.

This becomes even worse because the channels

of different Wi-Fi technologies do not overlap

and this generates additional interference issues.

Everybody can validate the common scenario

with his own Smartphone, that already today you

can see multiple Wi-Fi Access Devices from

neighbors in an apartment building, and these

Wi-Fi Access devices interfere already today and

it will become worse with increasing Wi-Fi

proliferation, Wi-Fi communication on Fairs

already fails today completely because of the

interference.

It is obvious, that the requirement for “Wi-Fi

interference avoidance” methods for other

technologies operating within the same band as

Wi-Fi will become more and more challenging.

Reliability measures:

Interference is not the only challenge for the reliability of a wireless technology. The figure below shows

the indoor propagation of a wireless technology.

As mentioned previously, if it would be possible to invent special spectacles, which are able to visualize

electromagnetic waves in homes, we would have more comprehension for this important fact.

Important for the deployment of wireless technologies for new applications is, that the wireless

transmission does not generate additional risks for the acceptance of the application.

Within the past 20 years, Gigaset has developed the DECT technology to a today highly reliable and

coexistent technology which can be applied to new application fields. Today a new technology, which is

intended to be deployed for a new mass market will meet high challenges because of the increasing

amount of wireless technologies at home and especially because of the increasing proliferation of wireless

broadband applications.

Figure 8: Channel Layout of the different Wi-Fi derivates (Source: Wikipedia)


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Figure 9: Indoor Propagation of wireless technology (Source: R.Struzak)

Using existing Infrastructure and known technologies

The advantage of the Wi-Fi technology today is the fact that Wi-Fi clients are able to connect to existing Wi-

Fi Internet Routers. This might change in the near future, since vendors of Internet Access Routers start to

integrate DECT2

But until the critical mass of Internet Routers has been generated and until data profiles are added to the

DECT integrations, all other technologies than Wi-Fi have to add an IP Gateway to their product offering.

into the Internet Access Router, so that the DECT technology is next to the Wi-Fi

technology the second relevant wireless technology within the Internet Access Router, Network Operators

are pushing these kinds of Devices. The Deutsche Telekom for example has announced in 2010 that they

push 130.000 Internet Routers per month with integrated Wi-Fi and DECT into the market.

Today there exist DECT base stations in the households, but these devices support only voice services and

the majority is not connected to the Internet, this is also going to be changed and Gigaset is forcing

additional IP connectivity into their devices.

Bluetooth is also available at homes, mainly integrated in the mobile phones and Smartphones, but

Bluetooth reflect another business model here. With Bluetooth LE (Low Energy) the Bluetooth Special

Interest Group forces to connect sensor networks via the Bluetooth enabled Mobile Phone or Smart Phone

to the Internet and the corresponding services. This model does not support the installation of stationary

sensors within the home.

The other technologies are not yet present at home and currently no relevant activities are seen which

could increase the amount of Internet Access Gateways with technologies like ZigBee, Z-Wave or Wave2M

to a critical mass.

2 When DECT is integrated into Internet Routers, it is sometimes also referred to as CAT-iq. CAT-iq is trademark of the DECT Forum and defines specific certification rules for application specific protocols, but CAT-iq and DECT are identical from a technology and regulative point of view.


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The use of existing infrastructure at home reflects the customer requirement of having lower costs for their

initial product purchasing, and here the existing Wi-Fi connection is a plus. On the other side it is

questionable whether the average user is able to connect Wi-Fi modules, which are integrated in

appliances or Consumer Electronics devices to the existing Internet Access gateway, since in most cases the

customer has to initiate the binding procedure and has to enter the Security keys.

It may be also a customer vale, when he gets a plug&play Base Station together with the initial sensor

purchase, where the sensors are already bundled and the customer can setup the system as easy as a

cordless phone at home.

Gigaset has recognized over years of customer insights, that a relevant topic for the adoption of new

applications is, whether the end customer trusts the underlying technologies, which he knows from other

applications. The majority of end-customers does not understand and does not care which technologies

are used, these topics are discussed by technology-agnostic end customers in internet fora and other

communication channels and from specialized journalists in different media.

This is not a technical issue; it is more an issue of acceptance of new technologies.

Gigaset experience is, that the promotion of new technologies, which are not yet proven in the market and

not known, are more challenging than promoting known technologies, which have been recognized from

other applications. DECT, Wi-Fi and Bluetooth have advantages here.

It has to be stated, that regarding reliability the DECT technology is obviously most advanced, because of

the simple fact, that it has been applied and further developed within the past 20 years for providing

cordless telephony service at home:

• in Germany it was a regulative requirement that the phone rings within 200 milliseconds after an

incoming call is indicated at the home phone

• it is still an essential requirement throughout Europe and abroad that it has always been

mandatory to enable an emergency call

• the home-phone must always ring, when a call comes in and the home-phone must always dial-out

• so because of the requirements of the telephony service of highest reliability the DECT technology

has been designed and further developed for highest possible reliability and low latency and within

the past 20 years it has become a matter of course, that DECT phones simply work, but this is

because of the high reliability and the low latency of the wireless technology.

Further technical requirements

Battery operations

The technologies ZigBee, Z-Wave and Wave2M have been especially designed to operate for multiple years


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with a battery. The established technologies Bluetooth, DECT and Wi-Fi have not had appropriate

technologies to meet these requirements.

Since 2008 the DECT technology has embedded the DECT ULE (Ultra Low Energy) and Bluetooth has started

around 2007 the Bluetooth LE (Low Energy) technology, Wi-Fi chipset vendors have started in 2009 with

Low Power Wi-Fi Chipsets.

The primary strategy to achieve multiple year battery operation is not to reduce the energy for transport of

data, because this is not possible. Physics teaches us that certain “Energy per transmitted Bit” is required to

transport data via an RF interface. You might send the data faster within a shorter period of time or you

might send the data less fast and take more time for this, but the energy per Bit is theoretically

independent from the transmission technology and modulation schemes.

The primary strategy is to sleep most of the time: All technologies have a “deep sleep mode”, where most

of the building blocks are sleeping and the sensor node consumes only few µA and thus is able to life for

years out of a single battery.

When data is required to be sent, the technologies have strategies implemented to wake up quickly, find

the wireless communication peer as fast as possible, send the data and then to fall quickly back into the

deep sleep mode.

The decisive factor for the battery lifetime is not the RF technology, but the application. An application,

which transmits data every 5 minutes over the air will have a lower battery life time than an application,

which sends data only once a day, therefore the focus is to design the application in that way, that the RF

technology is used as little as possible. Usually an application only sends data, when it is triggered by the

sensor hardware or when a timer has expired, so that the RF interface is activated only few times a day.

Battery to battery communication

One topic, which is called the “battery to battery communication”, has to be mentioned. In a system we

have generally two types of nodes: the sensors and the actuators. A sensor node can remain in deep sleep

mode, and when a sensor trigger occurs, it wakes up, sends data out to e.g. the internet and falls back to

deep sleep mode. An actuator is different; it can be triggered via the wireless interface from e.g. the

internet to perform a certain action. Therefore an actuator needs to stay attentive and needs to listen

regularly to the air, whether any commands or info is received via the wireless interface.

This means that current technologies have to stay awake and listen and therefore currently those

technologies cannot be battery operated, they currently need a power supply.

There are solutions possible to enable also actuators to become battery operated: One solution, which is

realized in proprietary 868/915 MHz technologies use a very narrow-band RF interface, and it is possible to

send a wake-up signal to that RF interface. In addition the RF receiver is so designed, that it can scan with

very low current consumption the receiver interface.

Gigaset as a technology leader in RF technologies is prepared to contribute to solutions for a battery to

battery communication within the DECT ULE technology and is expecting solutions for the DECT technology


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to enable this mode also.

Bandwidth

The statement, that sensor networks transmit only few portions of data is incorrect.

It is correct, that most of the time the sensor nodes only send low amount of data, which contain only few

bytes of information, but from time to time, higher bandwidth is required and the wireless technology

needs to support this. Gigaset is aware of requirements, which demand already today the need for a

certain bandwidth within the sensor nodes; these are required for actually following use cases:

• New technologies in several Gigaset sensor nodes, which cannot be disclosed yet, require the

functionality of Software Update over the Air, means that the system needs to send new firmware

into the sensor nodes to update them, therefore firmware update functionality is required.

• Requirements exist, that presence sensors are able to shoot a photo or start a short video after

having detected a presence or a movement.

The following table gives an overview of different technologies regarding data rate and support for the

mentioned applications:

Technology Frequency

MHz

Gross

Data Rate

Effective

Data Rate

Download of

100kByte

Software

Update

Upload of

VGA (640x480)

JPEG photo

basic quality

Video

support

MPEG4

Wave2M 868/915 19 kb/s1) 8 kb/s 128 sec 230 sec NO

ZigBee 2400 250 kb/s 127 kb/s2) 8,1 sec 14,5 sec Low

Bluetooth 2400 1 MB/s 434 kb/s 2,4 sec 4,2 sec OK 240p

Z-Wave 868/915 40 kb/s 10 kb/s3) 102 sec 184 sec NO

DECT 1900 1 MB/s 384 kb/s 2,7 sec 4,8 sec OK 240p

Wi-Fi BPSK 2400 1 MB/s 480 kb/s 2,1 sec 3,8 sec OK 240p

Wi-Fi 64QAM 2400 54 MB/s 13,7 Mb/s 0,1 sec 0,1 sec Good 1080p Table 2: Data rates and applications of wireless technologies 1): Gross data rate of up to 150 kbps, but most application use 19 kb/s, 50 kHz channel bandwidth, effective rate estimated 2): Jennic Application Note: JN-AN-1035 : Calculation 2006 3) Mikhail Galeev, Motorola eetindia.com & Mark E. Hazen, EWT Editor

Cost

Bill of Material and Conversion Costs are very important decision criteria for Gigaset, to decide for a certain

technology. This reflects the important customer requirement, to pay a fair price for the purchased

equipment.

Since the start of the European de-regulation in the 1990’s, Gigaset as important European brand and with


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the Siemens AG history, has developed a high competence for combining cost efficiency, quality and

innovations in its Consumer Electronics (CE) products. With the development and production of CE devices

in the German Factory in Bocholt, Gigaset has proven to compete with matchable Chinese products.

There are three relevant requirements for the Bill of Material and the chipset costs:

1. Performance requirements and memory requirements, since chip area and memory area are major

cost driver in wireless systems.

2. Maturity and Mass market adoption: High component volumes enable to spread the overhead

costs and hence reducing the overall price for a technology.

3. System concept: Can the application firmware run on the same Microcontroller, which controls

also the RF or is a separate Microcontroller with additional memory required ?

ZigBee, Bluetooth and DECT all have similar hardware and software requirements.

For example, the ZigBee software stack is around 100 Kbytes while DECT stacks have similar size – so

memory costs are similar for both technologies.

This means that the maturity of the technology and the volume of manufacturing are the main cost

differentiators for these technologies. DECT’s status as a mature, high volume technology is reflected by

current pricing. Today’s single-chip DECT SoCs are priced well below the ZigBee SoCs $2-3 range, and 300

Million DECT chips sold each year represent a healthy multi-vendor market guaranteeing low component

pricing and wide availability.

In general, Wi-Fi based solutions have a higher cost impact, because the Wi-Fi modules provide the physical

and the MAC layer of the wireless transport mechanism. A Wi-Fi module needs to be connected to a Host

processor, which then takes the data from the module and puts data into the module. The other

technologies are scalable systems, where the RF technology is an integral part of the overall system and

thus enabling lower cost of the overall system.

868/915 MHz System are generally cheaper, since they have a relative simple RF design and require less

performance and memory because of their low data rates.

Standardized technology has a general advantage over proprietary technologies, since standardization

enables chipset vendors to reach higher volumes with their chips than with proprietary technologies.

Especially emerging technologies promote the cost position, which can be achieved in future chipsets,

but having high cost position at current, because amortization of Chipset Development has to be reached

first. This is a big disadvantage for emerging technologies, next to the obvious risk, that emerging

technologies may not fulfill the promoted feature set.

Security

Security and Cryptographic is the most important topic for Gigaset’s approach to develop new sensor

networks, nothing is worse than if a burglar can get a dirty hack from the internet or from dark sources to

deactivate an alarm system or to unlock the door of a customer.

The following figure gives an overview of the relevant security fields.


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Figure 10: Overview of security architectures for Wireless sensor networks [source: Hani Alzaid, WSN security]

It can be deduced from this figure that Gigaset takes maximum care to develop the optimum security

architecture for their networks, aligned with the available resources within the Gigaset system.

Therefore the built-in security mechanisms of a certain technology are not the decisive factor for Gigaset to

decide for a certain technology. If a technology offers certain security mechanisms, which meets the

demanding requirements of Gigaset, then these may be implemented in the overall security concept. If

additional security or cryptographic levels are required, then these will be developed on top of the existing

software blocks of a technology.

In general Gigaset follows the strategy to use openly available security and cryptographic algorithms, which

are checked and challenged continuously by worldwide researchers and hackers.

Gigaset expertise and partnering With few discussion partners Gigaset experiences interesting dialogs like the following:

Discussion Partner: “Which wireless technology are you using for your sensor solution ?”

Gigaset: “ We are using DECT Ultra Low Energy !”

Discussion Partner: “DECT ? We don’t know this technology, what is that ?”

Gigaset: “You might know that from cordless telephones.”

Discussion Partner: “Yes, OK, but is this a technology for sensor networks ??”

Some companies do even not have the DECT technology on their radar, one main reason for this is, that all

the other wireless sensor network technologies experience heavy promotion by the technology vendors.

For DECT, a promotion like this does not exist, nearly all 300 million chipsets per year are sold to big

manufacturing companies, who make CE products using this technology.

Gigaset belongs to the leading DECT vendors and has furthermore a respectable quality brand in the

Consumer Electronics market space.


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The following figure shows the history of Gigaset as technology vendor and innovation leader:

Gigaset Communications has always beenLeader and Trendsetter in cordless DECT business

1941 1993 2003 2007 1877 2001 1997 2008 2009 2011

Though Gigaset has experience in many wireless technologies, as Wi-Fi and Bluetooth and further

proprietary technologies, it is one of the main drivers of the DECT technology. Gigaset has launched the first

DECT Phone ever in 1993 (under the predecessor brand Siemens Gigaset) and has since then further

developed the technology and the standard. In 2008, Gigaset engineers have managed to use a massive

steel frame as DECT Antenna, 2 years before other companies have issued similar applications.

Therefore it is obvious, that Gigaset – different from other companies – has also put DECT ULE to the

evaluation list for wireless sensor technology evaluation.

Gigaset is willing to help partners with the provision of the

Gigaset DECT ULE module “MD50”, which can be integrated into

Partner’s application, whereby partners will benefit from the

technology competence, the cost advantages and from the

quality of Gigaset technology – made in Germany.

Figure 11:Gigaset DECT ULE OEM module


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Summary Table As mentioned in the abstract, this table gives a summary of this whitepaper, which are explained in detail

within the referenced subclause,

Subclause Heading

and technology feature

Wave2M ZigBee Bluetooth Z-Wave DECT WiFi

BPSK

WiFi

64QAM

Range ++ – – – + ++ – – –

Interference , Reliability – – – – – – ++ – 2) – 2)

Etiquette, Reliability – – – – ++ – 2) – 2)

Existing infrastructure – – +3) – + ++ ++

Battery operations ++ ++ + ++ + + – –

Bandwidth – – – + – – + + ++

Cost1) + – ++ + ++ – –

Security + + + + + + +

Gigaset expertise – – + – ++ + + Table 3: Summary table of the subclauses in this whitepaper 1) Real today’s cost position is considered, not a reachable future cost position 2) Advantages for Wi-Fi are the high bandwidth and the Wi-Fi interference avoidance of other technologies 3) Via Smartphones / Mobile Phones

abstract - vogelfiles.vogel.de/vogelonline/vogelonline/companyfiles/6662.pdf · technical white...

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