4G LTE Opportunities & Challenges in DTT arena

Transcription

1 4G LTE Opportunities & Challenges in DTT arena DigiTAG Workshop Istanbul November 2013 Stan Baaijens, CEO Funke 1

2 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 2

3 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 3

4 4G LTE Challenges LTE uses frequencies belonging to the sub-band from 791 to 862 MHz: 791Mhz to 821Mhz: Downstream 832Mhz to 862Mhz: Upstream Broadcasting Downlink Uplink 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. 4

5 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: 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: 5

6 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 6

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 7

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. Source: 8

9 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. 9

10 The input spectrum of different signals Weak DVB-T/T2 w Moderate w DVB T/T2 4G LTE 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 10

11 Red trace = signal after amplification Black trace = input signal 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 11

12 Increased noise floor,so degrading STB Signal to noise ratio.. 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! 12

13 How to solve the challenge? Newest INERT 4G LTE Technology cheapest and best available solution 13

14 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]) 14

15 Standard available solution ANT LNA FILTER CABLE STB Simple,but not effective, amplifier is still under pressure 15

16 OPTIMAL SOLUTION 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 low loss filtering,for further rejection 4G LTE Very high IP3 LNA with still a low noise figure FILTER LNA FILTER FILTER CABLE STB 16

17 Standard DTT transmitted signal 17

18 LTE 4G and DTT signal reception 18

19 LTE 4G Funke INERT Technology 19

20 4G LTE INERT technology tested at IRT Germany 20

21 To conclude 21

22 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) 22

23 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! 23