What exactly is LTE?

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stantorres

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I understand the basic concept around TDMA, CDMA, P25, DMR, etc. There is a carrier, a certain number of kilohertz wide, there is digital modem sounding stuff which is 1's and zero's. The data is either organized in time slots or by code slots.

I'm told that LTE is very different. Super wide, something about a noisefloor.

What is LTE? Can it be monitored?

I ask in the context that I believe all public safety radios will eventually be VoIP over LTE.

I am NOT talking about cellular phones or encrypted. I'm talking about listening to the local fire department, just like we do now, once they migrate to LTE.
 

mmckenna

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I understand the basic concept around TDMA, CDMA, P25, DMR, etc. There is a carrier, a certain number of kilohertz wide, there is digital modem sounding stuff which is 1's and zero's. The data is either organized in time slots or by code slots.

I'm told that LTE is very different. Super wide, something about a noisefloor.

What is LTE? Can it be monitored?

I ask in the context that I believe all public safety radios will eventually be VoIP over LTE.

I am NOT talking about cellular phones or encrypted. I'm talking about listening to the local fire department, just like we do now, once they migrate to LTE.
It's a very wideband data stream. I'll let you google the details.
Not monitor-able with consumer equipment.

As for public safety radios eventually being VoIP over LTE, I think there's a bit of a misconception about LTE, FIrstNet and how it applies to public safety users.

FirstNet, using the LTE waveform, is intended to be a data service primarily. While there are plans to include a Push To Talk service on it, it's not the primary role. Even FirstNet will tell you that while it may be able to replace LMR radio systems at some point in the future, they are not expecting public safety to ditch their two way radio systems any time soon.

The LTE data stream will be encrypted, just like the consumer services are. Even if someone comes out with a device that will monitor FirstNet, there's the encryption/laws that have to be overcome.

Your scanner is safe for a while.
 

Ubbe

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I beleive Motorola are working with Ericsson since 4 years back to design a public service LTE net. Ericsson have left the 2-way radio market so there are no longer a competitor conflict.

It will be a seperate net much like the current public service nets but will have a huge data capacity that the current systems lack. These last months the 700MHz band have been cleared from terrestial television channels to make room for future uses here in Sweden. The bid for the 700-800MHz range have not started yet but all mobile phone services already have the 800MHz and upwards to use.

/Ubbe
 

bchappuie

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LTE is a modulation technique that is kinda a mix of CDMA and TDMA. In most if not all LTE networks, it is a carrier for IP, which inherently uses IPV6 which is encrypted with IPSEC by default. There is no way to decode it over the air. Qualcomm will ensure that. They own the code used by all wireless carriers today. First Net is being sold to LEC's as a high speed data network, with features already in wireless carriers network, such as VOIP, and PTT, however only data will have capability for preemption and prioity on the network. WPS may be introduced on VOIP calls for priority.
 
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DaveNF2G

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The original meaning of LTE was "Long Term Evolution", a generic term for systems that would take a longer time to develop and build out than even the "Slow Growth" category then permitted by the FCC. As has occurred with other common words (privacy, interoperability, P25, etc.), the generic abbreviation has been attached by some companies to specific products.
 
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The original meaning of LTE was "Long Term Evolution", a generic term for systems that would take a longer time to develop and build out than even the "Slow Growth" category then permitted by the FCC. As has occurred with other common words (privacy, interoperability, P25, etc.), the generic abbreviation has been attached by some companies to specific products.


Eh, more of a set standards to provide capable handsets with backwards compatibility much like P25. LTE relies largely on software defined infrastructure though so it can be modified for long term evolution. Similar to how P25 Phase 2 infrastructure is capable of interfacing with Phase 1 subscribers as the signaling on the control channel is backwards compatible.

VoLTE solutions for are still 5-10 years from even being practical solutions for many agencies as the existing infrastructure simply doesn’t exist currently, the 2100 ms latency is considered too great for public safety grade voice due to the current way audio is processed via DSP, etc.

It’ll be awhile before the cost of a truly equivalent Technology is comparable to both the end user and the system owner when it comes to the quality of voice being passed reliably over a network.


Sent from my iPhone using Tapatalk
 
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