4G LTE Opportunities & Challenges
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Transcript of 4G LTE Opportunities & Challenges
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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
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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.
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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.
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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
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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])
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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 !