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4G LTE Opportunities & Challenges

in DTT arena DigiTAG Workshop Istanbul

14-15 November 2013

Stan Baaijens, CEO Funke

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Why 4G LTE (Long Term Evolution)

The unrelenting growth of smartphone and tablet use and associated new forms of communication, both free and paid, are pushing mobile data traffic to new heights

Demand for broadband Internet on mobile has not stopped growing in recent years and there is every indication that it will continue to do so in the near future which Telcos push to enter new markets (tv in this case)

The goal of LTE is to increase the capacity and speed of wireless data networks using new DSP (digital signal processing) techniques and modulations that were developed around the turn of the millennium

Users want increasingly faster and more efficient mobile access to the Net, a desire that has culminated in the creation of LTE (Long Term Evolution) or defined for some as an evolution of the 3GPP UMTS (3G) standard, for others as a new concept of dynamic architecture (4G).

However it is clear is that LTE will be a key factor for the deployment of mobile internet for two main reasons:

Users want a data connection that downloads and uploads at a faster speed Manufacturers and operators want a less complex standard that reduces costs

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4G LTE Opportunities

Users want increasingly faster and more efficient mobile access to the Net, a desire that has culminated in the creation of LTE (Long Term Evolution) or defined for some as an evolution of the 3GPP UMTS (3G) standard, for others as a new concept of dynamic architecture (4G).

However it is clear is that LTE will be a key factor for the deployment of mobile internet for two main reasons:

Users want a data connection that downloads and uploads at a faster speed

Manufacturers and operators want a less complex standard that reduces costs

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4G LTE Challenges

LTE uses frequencies belonging to the sub-band from 791 to 862 MHz:

791Mhz to 821Mhz: Downstream

832Mhz to 862Mhz: Upstream

The small separation between the band reserved for TV and the LTE band (just 1Mhz), as well as the

transmitting power it uses (up to 67 dBm of PIRE) make downstream the signal with the most

interference of the two. This signal must be blocked, using antennas with special technologies (Funke

INERT technology) and filters, before any amplifier in the trunk installation. And it will protect the

installation from interference that can filter through the capturing system

However, the damage that can be caused by the signal transmitted by 4G LTE mobiles is not negligible.

As this signal (upstream) is much less powerful than the previous one, it has the disadvantage of being

close to the input points: Televisions, antenna, stb, , outlets, cables in bad condition

For that reason, we have to guarantee the correct 4G LTE FREE devise and the use of user filters

connected to receivers (TV, STB) to prevent the entry of interference in the distribution network via these elements.

Broadcasting Downlink Uplink

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Interferences recognized by 4G LTE signal

The use of LTE devices such as LTE mobile telephones or LTE base stations can cause

interference to the digital terrestrial (DVB-T/T2)- and / or digital cable (DVB-C/T2) TV of the

LTE user himself or that of his neighbors, when the frequencies coincide. Interference is

expected to digital terrestrial (DVB-T/T2) l- and / or digital cable (DVB-C/C2) TV reception

(source: http://aps2.toshiba-tro.de/kb0/TSB21038P0000R01.htm)

The research is undertaken by Excentis states that

the required distance to avoid interference varies between different models of consumer premises equipment, but for some models a distance of even more than 6

meters is required

The report cites an example where 35% of LTE devices used in urban areas will have to operate at "high power" and at these levels would likely cause interference if the user

came within 3 meters of in home consumer equipment (source: http://www.cellular-

news.com/story/45575.php)

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4G LTE Resolutions DVB-T /T2 devices and the corresponding antenna (aerial) are designed to receive radio signals in the 800

MHz band. A too strong LTE-800 signal can interfere and affect the DVB-T signal or even superimpose it.

Possible effects are

picture and sound interferences (single pixel failures or sound disruptions), a frozen picture and in the worst case, a complete loss of the signal.

Compared to analogue broadcasting, interferences when using digital broadcasting appear suddenly and can appear through a insignificantly degradation of the reception situation.

Interferences can arise from irradiations of LTE-base stations and LTE-end devices (e.g. a USB surf stick,

modem or mobile phone). Mostly the interference of the end devices is more problematic because it's nearer

to the DVB-T/T2 recipient. In addition a LTE-end device does not constantly send data.

Whether interferences appear depend on a multiplicity of different factors. Not only the signal strength of

DVB-C or DVB-T must be considered, also the broadcast- and recipient situation of LTE. In addition the used

devices, cables and antennas are very important.

Example of DVB-T/T2 interferences

Source http://aps2.toshiba-tro.de/kb0/TSB21038P0000R01.htm 7

Interferences within household

When interferences appear in households, which are using a LTE-end device, it should

be more or less simple to find a remedy:

First of all the end device should be located preferably far away from the

disturbed TV-recipient or the antenna should be rearranged, ideally in another

room.

Furthermore it's important to have a good reception quality of the end device,

best would be if it's located near a window.

A better connection quality between the base station and the end device is

decreasing the transmission power.

Source: http://aps2.toshiba-tro.de/kb0/TSB21038P0000R01.htm 8

4G LTE interferences from outside

Should the DVB-T/T2 signal will be received via a antenna which is installed on the outside, another

antenna type can solve interferences which are caused from LTE-800 (change of the Omni-directional

antenna to a directional antenna).

Compared to a Omni-directional antenna, a directional antenna can be directly aligned to the DVB-

T/T2 broadcasting tower (this does not help, when the LTE-800 transmitter is located in the same

direction).

If the DVB-T/T2 signal will be received via a indoor antenna, the location of the antenna can be

modified. If this does not improve the situation which normally an antenna with a very good LTE

latest technology and a good filter should solve the problem), a directional antenna can put things

right.

A comparatively simple and effective solution can be a LTE-cut filter between the DVB-T/T2 antenna

and the TV. Corresponding filters should allow to pass through the TV-signal and block completely

the LTE-signal. Regarding the little frequency spacing between LTE-800 and DVB-T/T2, this solution

does only work with some restrictions.

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Interferences through LTE signals

Overload : a system gets overloaded if the sum of the signal power at

the input exceeds a certain threshold.

Since this is depending on the cumulative effect of a number of different

signal levels, the severity of the interference will vary depending on

geographic region

If a system is in overload the ability to cope with adjacent channel

interference falls

Degradation of receiver Signal to Noise ratio.

The input spectrum of different signals

The input spectrum of antenna and LNA, showing the LTE signals with relative high

input level and one DVB-T/T2 signal with moderate level plus one weak DVB-T/T2 level

4G LTE SIGNALS w Weak DVB-T/T2 w Moderate DVB T/T2

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The red trace demonstrates the output signal of a LNA with a high IP3 figure = +34dBm,spectrum looks ok

Black trace demonstrates the input spectrum Spectrum looks good, no distortions or harmonics

Red trace = signal

after amplification

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Black trace = input

signal

The blue trace shows the ouput signal from a LNA with IP3=+22 dBm -> LNA is now overloaded, DVB-T/T2 channels are destroyed through distorsion/noise of LNA

The green trace shows the output from an LNA with a IP3=+34 dBm,spectrum looks ok Be aware that the whole receiving UHF band is affected during overload!

Increased noise floor,so

degrading STB Signal to

noise ratio..

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Black trace: Input

signal

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How to solve the challenge? Newest INERT 4G LTE Technology

cheapest and best available solution

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Relevance of filtering becomes more important now as the spectrum becomes

over-crowded, often with (very close by) adjacent with relatively high power, like

4G LTE, GSM...

Since 4G LTE is very close by (in frequency), steepness of gain curve must be high

and fall-off frequency reproducible (in mass production).

As explicit Funke IP, our compact PCB implementation is very well suitable to full

fill these requirements.

Can be adapted by design - for future LTE requirements (e.g. 700 [MHz])

Standard available solution

ANT

LNA FILTER CABLE

Simple ,but not effective, amplifier is still under pressure

STB

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ANT

The structure on the antenna is

created in such way that it

rejects 4G LTE interference

without introducing loss for the

wanted receiving range by EM

filtering

LNA FILTER

CABLE STB

FILTER FILTER

Very high IP3 LNA with

still a low noise figure

low loss filtering,for

further rejection 4G LTE

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OPTIMAL SOLUTION

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Standard DTT transmitted signal

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LTE 4G and DTT signal reception

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LTE 4G Funke INERT Technology

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4G LTE INERT technology tested at IRT Germany

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To conclude

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DTT reception (in 4G LTE network)

With the new technology there are always opportunities and challenges

Today DTT signal intermixed with 4G LTE

4G LTE signals typically have high levels (high power) compared to DTT signal power

which causes interferences

Both DTT and 4G LTE are absorbed by antenna

Pre-amp saturated, in particular when its IP3 is low, it means that antenna is

overloaded and blocks due to too strong signals when IP3 is low

Outputted signal is distorted, causing demodulator errors in STB, it results that the

tv screen is blocked (frozen)

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DTT solution within 4G LTE arena

Demand for broadband & watching tv on the move

4G LTE is real and active in many countries already in 800MHz

There are/will be some interference issues in DTT

Newest 4G LTE INERT technology available brings the solution - antenna

is insensitive to 4G LTE signals or 4G LTE signal is NOT picked up by the

antenna

Important that electrical signal is free of 4G LTE components and as such

within operational limits of pre-amp and STB

Grab the opportunities given and limit the challenges !