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SVLTE and Tri-band LTE – Provider/Device Capabilities


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This came about from someone’s post over on XDA and my response to it (link) in which I promised to check its accuracy with the gurus here. Basically, the poster interpreted the lack of SVDO/SVLTE on the Sprint HTC One M8 as an “oversight,” and I respectfully disagreed, but it raised a few questions that I haven’t been able to answer.

1.) Will Sprint be transmitting LTE on more bands nationwide than the other carriers?
2.) If the answer to question 1 is “yes,” then does tri-band LTE come at the cost of SVLTE because Sprint tri-band phones will be switching between bands more frequently so the network can distribute the load?

Here’s my rationale:

1.) Knowing that NV rollout is nationwide, and knowing that the end-goal is to have 2600 and 1900 MHz on all towers as well as 800 MHz LTE on 80% of the towers, it’s safe to say that Sprint will have tri-band LTE across the country.  From what I understand, AT&T, T-Mobile, and Verizon might only have 1 or 2 bands per market (maybe more in certain places for AT&T/T-Mobile):
 

AT&T: 700/AWS/1900/2300 MHz
Sprint: 800/1900/2500 (2600) MHz
Verizon: 700/AWS MHz
TMUS: 700/AWS/1900 MHz

Sources:
List of LTE networks - Wikipedia
AT&T Mobility - Wikipedia
Sprint - Wikipedia
Verizon - Wikipedia
T-Mobile USA - Wikipedia
 
2.) Since the other carriers have fewer bands in a given region, the phones will be switching between them less, leaving extra room (for lack of a better word) for SVLTE on certain devices.  Since we’re talking about the HTC One M8, let’s use it as an example.  Here are the frequencies for each of the carrier-specific models:
 

AT&T: 700/850/AWS/1800/1900/2600 MHz
Sprint: FDD 800/1900 MHz , TDD 2600 MHz
Verizon: 700/AWS/1800/2600 MHz
TMUS: 700/AWS MHz

Source: M8 spec page

AJ referenced this issue with the radio paths which may be related to this (not for the M8, but possibly still applicable):
 

Now, one reason for that could be largely, even exclusively Sprint specific because Sprint is running CDMA2000 and LTE in the same PCS 1900 MHz band.  Off the top of my head, I can think of no other operator in the world running CDMA2000 and LTE in the same frequency band.  So, for SVLTE devices, that presents a filter challenge.  Both of the two separate radio paths are transmitting/receiving at similar PCS frequencies, and they are only centimeters, even millimeters apart inside the handset.  Keeping CDMA1X 1900 from interfering with LTE 1900 and vice versa becomes a challenge or a shortcoming of SVLTE devices.


…which prompted the following question in that same thread which remains unanswered:
 

But if thats the case in a triband phone wouldn't it be easier to handle than on a single band hone since during a call say 1900, just have the phone use LTE band 41 or fallback to 800Mhtz for LTE to preserve SVLTE (while not causing 1900 issues)?

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No provider has SVLTE capable devices except Verizon (on new devices).  AT&T and Tmo do not have SVLTE.  They fallback to their 3G network to do voice and data together.  Verizon is the only one who has decided to run dual transmission paths for LTE and pay the price accordingly to allow SVLTE.  This is not a network issue, it is a device issue.

 

The more bands you add, it becomes more and more difficult and expensive to try to keep dual path transmission for LTE and a 3G voice technology to be used together.  And it becomes really difficult when one of those bands is TDD (supposedly).

 

Robert

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This is turning into a place where trolls can bash Sprint, and extol the virtues of Tmo.  I am closing the thread and posts have been removed.  This is OLD NEWS, and has been discussed to death throughout our forums.  No one is saying anything new, including me.  

 

If someone needs simultaneous voice and data, they will need a Sprint Uniband device or another provider.  Period.

 

Robert

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