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LTE

Prevent LTE Mobile Broadband interference with your TV Picture

In European countries the frequency band 790-862MHz (channel 61-69) is gradually being discontinued for DTT use (Digital Terrestrial TV). In the future this frequency band is used for mobile broadband services using LTE (Long Term Evolution) and/or LTE Advanced technology.

LTE technology operating in the 790-862MHz frequency band raises challenges within installed DTT and CATV (Cable TV) networks, which historically are developed to operate within these frequencies:

DTT (Digital Terrestrial TV)

  • Challenge with Frequency Separation: LTE transmissions (starting from channel 61) are close to DTT channel 60, with potential neighbor and near channel interference
  • Solution: High performance Band Stop Filters to reject LTE signals, and new antennas customized to receive up to channel 60 only.
  • Challenge with Amplifier/TV-tuner Overload: Problems are expected primarily in rural areas where LTE transmission levels are expected to be highest, potentially overloading DTT mast amplifiers and TV-tuners located close to the LTE transmitter.
  • Solution: Sharp Band Stop Filters, low noise/high input amplifiers, and new antennas customized to receive up to channel 60 only. Important to place filter as close to antenna as possible and before antenna amplifier, TV-tuner, set-top-box and TV.

CATV (Cable TV)

  • CATV is considered a closed network and channel 61-69 will continue to be used in CATV networks. In other words, CATV channels will have to co-exist with channel 61-69 LTE transmissions.
  • Solution: Strong shielding in CATV networks is critical and important and is something that CATV network operators historically have been well aware of. Studies do however indicate that higher shielding could be required (new higher shielding classes Class A+, Class A++ have been defined).

DTT and CATV - Common Challenge

  • Challenge with In-house Shielding of TV Network. “A chain is no stronger than its weakest link” and the TV network goes all the way up to the connector on the back of the TV (being it Coax, HDMI or other connector). LTE transmissions will find the weakest link in your TV-network chain, where shielding is lowest, and the LTE interference will enter the network. This is why interference free TV picture quality, requires proper shielded cables, taps and splitters, outlets, drop cables and connectors.
  • Ensure to use high shielded cable (Class A or A+) and high shielded connectors (Class A or A+) throughout your installation.
  • In other words, an interference free TV viewing experience also requires a quality shielding in-house network.

Triax has developed a range of products, which will protect your network from LTE Mobile Broadband interference.

Look for the “LTE Protected – by Triax” logo, to ensure that your product meets the Triax requirements giving you a perfect TV picture experience.

 

LTE and LTE Advanced explained

DTT transmissions will be transmitted up to channel 60 (790MHz). Only a 1MHz “Guardband” (790-791MHz) separates DTT and LTE transmissions.

791-821MHz is the “Downlink” frequency area used by the LTE transmission base stations to transmit/broadcast LTE. The “Downlink” frequency area is where the highest transmission levels are expected.

821-832MHz is a frequency area not used for LTE. It is a spectrum with free use for wireless microphones.

832-862MHz is the “Uplink” frequency area used by the LTE terminals (LTE phone, LTE modem, dongle etc.) to respond to the base station transmission.

See below illustration of the LTE frequency spectrum with “Downlink” and “Uplink” areas highlighted.