1. zehkaiser's Avatar
    Sorry if this has been discussed a lot, but I'm having trouble finding reliable and consistent information.

    I have been told that T-Mo plans to have their full LTE network upgraded by the middle of this year. It was explained that when this is done, every tower will have LTE and all lower techs (2/3/4G). Is this true? And are there any reliable sources to back up this claim?

    Posted via CB10
    04-02-15 09:50 PM
  2. raino's Avatar
    What they're said to be doing by the end of this year is converting the bulk of their 1900 MHz 2G spectrum to LTE. They'll still leave some 2G around (for people with older phones and what not.) It's a pretty ambitious goal, and if Neville Ray (their CTO) can pull off...hats off to him. Here is a press release: T-Mobile Celebrates 1st Anniversary of LTE Rollout By Launching Major Network Upgrade Program | T-Mobile Newsroom

    Here is more: https://www.telegeography.com/produc...twork-for-lte/

    As far as having "LTE and all lower techs (2/3/4G)" on the same tower goes, I'm not sure if this is possible. Of course, they can always throttle speeds but when they do that, your phone still shows LTE...but you know based on speed that it's anything but.
    04-02-15 10:04 PM
  3. gariac's Avatar
    What they're said to be doing by the end of this year is converting the bulk of their 1900 MHz 2G spectrum to LTE. They'll still leave some 2G around (for people with older phones and what not.) It's a pretty ambitious goal, and if Neville Ray (their CTO) can pull off...hats off to him. Here is a press release: T-Mobile Celebrates 1st Anniversary of LTE Rollout By Launching Major Network Upgrade Program | T-Mobile Newsroom

    Here is more: https://www.telegeography.com/produc...twork-for-lte/

    As far as having "LTE and all lower techs (2/3/4G)" on the same tower goes, I'm not sure if this is possible. Of course, they can always throttle speeds but when they do that, your phone still shows LTE...but you know based on speed that it's anything but.
    Each mode has its own modulation, so it wouldn't be a matter of throttling. I think they just divide up the spectrum into segments for each mode.

    I've spent much of today in 4g. Maybe they are messing with the LTE network. I booted the phone and it didn't help.

    Posted via CB10
    raino likes this.
    04-03-15 03:29 AM
  4. zehkaiser's Avatar
    Thanks for the article! Unfortunately, it's what I suspected. They're upgrading MOST of their towers. Also, there's no mention of adding 3/4G with LTE.

    Posted via CB10
    04-03-15 06:29 AM
  5. modifier's Avatar
    As far as having "LTE and all lower techs (2/3/4G)" on the same tower goes, I'm not sure if this is possible. Of course, they can always throttle speeds but when they do that, your phone still shows LTE...but you know based on speed that it's anything but.
    1900MHz 2G and 1900MHz LTE coexist on towers now and don't impede each other's signals or speeds. You can test your local LTE tower by switching your phone to 2G service to see if the tower downgrades you gracefully (and vice versa). Similarly, VoLTE calls won't be affected if a legacy 2G user lands on the same cell site.

    Try it and let us know your results.

    [CB10 / Q10]
    raino likes this.
    04-03-15 09:28 AM
  6. raino's Avatar
    1900MHz 2G and 1900MHz LTE coexist on towers now and don't impede each other's signals or speeds. You can test your local LTE tower by switching your phone to 2G service to see if the tower downgrades you gracefully (and vice versa). Similarly, VoLTE calls won't be affected if a legacy 2G user lands on the same cell site.
    How would I know if I'm still on the same tower when dropping from LTE to 2G? From what you're saying it sounds like I would get dropped to bona fide 2G which these towers support, and not throttled-down LTE.

    What you're saying makes sense because not everyone is going to upgrade to LTE phones at the same time, not to mention the people who use non-TMO supported phones and can't do voLTE.

    Is this possible only on the 1900 MHz towers or the 1700 ones as well (except instead of 2G, I'd be switching my phone to 3G/'4G' mode?)
    04-03-15 01:45 PM
  7. gariac's Avatar
    The tower ID for 2g and LTE is different. I don't think there is a foolproof way to tell if you are on the same tower unless you had all the relevant network information. But I would expect the 2g RSSI to be within a few dBm of the LTE tower. I think LTE has a greater TX power.

    Posted via CB10
    04-03-15 08:09 PM
  8. modifier's Avatar
    How would I know if I'm still on the same tower when dropping from LTE to 2G? From what you're saying it sounds like I would get dropped to bona fide 2G which these towers support, and not throttled-down LTE.
    You'd have to be near the tower in question and confirm tower IDs. If you're only testing data speeds then I might have misunderstood your question since throttled LTE data can be caused by any number of reasons. Being on the same tower as one broadcasting 2G isn't one of them since most towers broadcast legacy 2G as it's used for emergency purposes and to support older handsets.

    Is this possible only on the 1900 MHz towers or the 1700 ones as well (except instead of 2G, I'd be switching my phone to 3G/'4G' mode?)
    If a 1700 MHz antenna is set to broadcast LTE and 3G for legacy purposes then I suspect this test would work the same. You'd have to pay close attention to tower IDs and confirm that you're truly at 1700 in both cases.

    [CB10 / Q10]
    raino likes this.
    04-04-15 11:35 AM
  9. raino's Avatar
    If you're only testing data speeds then I might have misunderstood your question since throttled LTE data can be caused by any number of reasons. Being on the same tower as one broadcasting 2G isn't one of them since most towers broadcast legacy 2G as it's used for emergency purposes and to support older handsets.
    No, no I actually meant real 2G--where the phone shows 2G and not LTE. So you and gariac answered my question. Either way, whether it's throttled down LTE or true 2G, the answer is 'confirm tower ID.'

    If a 1700 MHz antenna is set to broadcast LTE and 3G for legacy purposes then I suspect this test would work the same.
    So is this something TMO's been doing that's you guys know of, like you do about the dual network 1900 MHz towers? It would make sense to make 1700 MHz towers dual network only in those theoretical places where they don't have any PCS spectrum, just AWS spectrum--currently deployed as a UMTS network. Then they could keep 3G as the secondary legacy network on those towers whereas 2G on PCS is the legacy in most places.
    04-05-15 07:52 PM
  10. gariac's Avatar
    I am under the impression that these cellular companies can do anything in the bands they own. For instance there is a UMTS band 2 and LTE band 2. I think (but don't know for a fact) that they can split the band to do both modulation modes.

    When you look up these cellular licenses in the FCC database, there is no emission code.

    Posted via CB10
    04-05-15 09:47 PM
  11. raino's Avatar
    I am under the impression that these cellular companies can do anything in the bands they own. For instance there is a UMTS band 2 and LTE band 2. I think (but don't know for a fact) that they can split the band to do both modulation modes.
    I'm interested in what modulation (if any) they have planned for the current UMTS 1900 towers. Are they going to refarm to LTE and keep HSPA+ on them or drop the second mode to true 2G? Would it be costlier to down-modulate existing HSPA+ on these UMTS 1900 towers to 2G than it would be to keep them HSPA+ on one mode and LTE on the other?

    It's a much simpler question with UMTS 1700: are they planning to modulate or not--since there's no GSM 1700 phone band or mode.
    04-05-15 10:48 PM
  12. gariac's Avatar
    I'm interested in what modulation (if any) they have planned for the current UMTS 1900 towers. Are they going to refarm to LTE and keep HSPA+ on them or drop the second mode to true 2G? Would it be costlier to down-modulate existing HSPA+ on these UMTS 1900 towers to 2G than it would be to keep them HSPA+ on one mode and LTE on the other?

    It's a much simpler question with UMTS 1700: are they planning to modulate or not--since there's no GSM 1700 phone band or mode.
    I don't think they "down modulate", mostly because I don't know what that means. ;-) But my guess is they litterally have a modulator for 2g in addition to LTE, or they can use one modulator to do both. They just have to chop up the band for each type of radio.

    If you recall at one time the iphone (unknown flavor) could only do edge on Tmo. When TMobile got the iphone, they used some secret fu to give them 3G. Like they allocated a part of the 2G band and let it do 3G.


    Posted via CB10
    04-06-15 01:07 AM
  13. modifier's Avatar
    I assume most if not all carriers are planning to support LTE + legacy on the same pole whether that be 2G or 3G. I don't know of a good reason not to run a dual broadcast since LTE phones aren't the norm. Even if a carrier adds an antenna somewhere, there's a good chance it will broadcast LTE + legacy since the cost to run both isn't any higher to my knowledge.

    Think of it like a wireless router capable of 802.11a, b, g, n, and ac using the same antennas and two main frequencies. A user on b shouldn't affect one on g, n, or ac despite being on the same spectrum. Even if you want n or ac only, legacy options are thrown in for free.

    [CB10 / Q10]
    raino likes this.
    04-06-15 09:33 AM
  14. gariac's Avatar
    I assume most if not all carriers are planning to support LTE + legacy on the same pole whether that be 2G or 3G. I don't know of a good reason not to run a dual broadcast since LTE phones aren't the norm. Even if a carrier adds an antenna somewhere, there's a good chance it will broadcast LTE + legacy since the cost to run both isn't any higher to my knowledge.

    Think of it like a wireless router capable of 802.11a, b, g, n, and ac using the same antennas and two main frequencies. A user on b shouldn't affect one on g, n, or ac despite being on the same spectrum. Even if you want n or ac only, legacy options are thrown in for free.

    [CB10 / Q10]
    If they are chopping up the band (frequency slices) to supply legacy modulation, they are reducing capacity in the primary mode (presumably LTE).

    There may be a legal requirement to support the old modes. There were a few lawsuits when the US went from analog to digital cellular. There were a lot of "telematics" built around analog cellular. These systems had contracts for service, and going from analog to digital basically killed the service. My recollection is the city of San Jose had some sort of sprinkler control on analog cellular and sued to recoup the cost of scrapping the system. I had a car using analog cellular telematics/voice and received a number of warning notices that the system would no longer work.



    Posted via CB10
    04-06-15 12:21 PM
  15. raino's Avatar
    If they are chopping up the band (frequency slices) to supply legacy modulation, they are reducing capacity in the primary mode (presumably LTE).
    Just to be clear, when we say 'chopping up,' we don't mean reserving, say, 5x5 for 2G on a 20x20 channel? In other words, the entire 20x20 will be simultaneously available for LTE and 2G?
    04-06-15 12:55 PM
  16. modifier's Avatar
    Just to be clear, when we say 'chopping up,' we don't mean reserving, say, 5x5 for 2G on a 20x20 channel? In other words, the entire 20x20 will be simultaneously available for LTE and 2G?
    Reserved != chopped up. You're probably thinking about a different animal here.

    GSM is a modified form of TDMA and gets "chopped up" no matter what. Overlapping IP-based traffic (IMS / LTE) with legacy time-division digital shouldn't divide a modem any worse than if all clients on a tower were of the same type (ie: all GSM or all LTE). The magic telephony box (sarcasm) inside the tower can only handle a finite amount of traffic before it kicks new users off and forces them onto a different tower regardless. That's why so many towers are being built.

    Bandwidth is generally akin to how the cable companies do it. With more users in an area -- or on a tower in this case -- data can slow down due to the inability to handle high amounts of packet traffic (yes, "chopped up" data) or because the carrier only allots X amount of total bandwidth for all users despite having the payload. Recall what the iPhone did to AT&T's bandwidth in big cities and you'll get the basic picture.

    But, having 2G/EDGE and VoLTE/LTE on the same 1900MHz aerial stick typically should not affect each other outside of normal demand limitations.

    [CB10 / Q10]
    04-06-15 06:03 PM
  17. gariac's Avatar
    I understand the 2g TDMA. (The TDMA caused a rather recognizable QRM in radios and other electronic devices, especially condenser microphones.)

    I think they are actually reserving a slice of spectrum, so 15MHz might be 14.5MHz in real life.

    Again think back to how they hacked the system to get the iphone working on 3g. Unfortunately that is a tough thing to Google.

    Legacy support is a pain.

    Posted via CB10
    modifier likes this.
    04-06-15 08:22 PM
  18. modifier's Avatar
    Agreed. Legacy support is a huge pain. The transition from AMPS/NAMPS to TDMA/CDMA/FDMA was enough of a headache.

    Now that cellular handsets are approaching ubiquity and have surpassed being viewed as only a luxury item, the roadmap has a more concise direction with vendors finally striving for a common path in LTE.

    VoLTE should be the nail in CDMA's proverbial coffin and make handset radios relatively universal, save for their respective LTE bands. Then it's just a matter of radio chipset firmware and antenna tweaking.

    It will take time but I predict devices with full interoperability between carriers worldwide. There will be one version of a phone with no more sub models.

    Raino may be out of a job at that point since his BB model lists will be rendered obsolete except for legacy device support purposes. :P

    [CB10 / Q10]
    raino likes this.
    04-07-15 12:03 AM
  19. raino's Avatar
    Again think back to how they hacked the system to get the iphone working on 3g. Unfortunately that is a tough thing to Google.
    I think that was planned refarming--sped up perhaps by the need to accommodate the iPhone. I'm not sure if they did this modulating thing then, but there wouldn't have been a pressing need IMO because 1) you can make calls on UMTS, and 2) A lot of these places already had existing UMTS 1700 coverage, so customers without the iPhone wouldn't have been too negatively affected by the refarm.
    04-07-15 12:44 AM
  20. raino's Avatar
    VoLTE should be the nail in CDMA's proverbial coffin and make handset radios relatively universal, save for their respective LTE bands.

    It will take time but I predict devices with full interoperability between carriers worldwide. There will be one version of a phone with no more sub models.

    Raino may be out of a job at that point since his BB model lists will be rendered obsolete except for legacy device support purposes. :P
    Man...I'm all for progress, but with each generation, the fragmentation increases. Four global GSM bands, at least six UMTS bands, a million LTE bands. This does not bode well for portability of phones. So raino will stay gainfully employed at his $0/year CB job

    Seriously though...it would be nice if future US phones come with all major LTE bands (yes, including Sprint's...) But will Sprint and Verizon voluntarily open their LTE networks up to BYOP?
    lift likes this.
    04-07-15 12:59 AM
  21. gariac's Avatar
    Man...I'm all for progress, but with each generation, the fragmentation increases. Four global GSM bands, at least six UMTS bands, a million LTE bands. This does not bode well for portability of phones. So raino will stay gainfully employed at his $0/year CB job

    Seriously though...it would be nice if future US phones come with all major LTE bands (yes, including Sprint's...) But will Sprint and Verizon voluntarily open their LTE networks up to BYOP?
    Supposedly what the iphone buyers do is get an unlocked Verizon iphone,then run it on ATT or TMobile. Supposedly it has all the GSM bands. That is, they don't really want to use Verizon, but the phone has better resale value because the phone could be put back on Verizon by the buyer.

    Apple is really working hard to make a world phone. The only problem is none of the radios work well.

    Posted via CB10
    04-07-15 02:28 AM
  22. modifier's Avatar
    Man...I'm all for progress, but with each generation, the fragmentation increases. Four global GSM bands, at least six UMTS bands, a million LTE bands. This does not bode well for portability of phones. So raino will stay gainfully employed at his $0/year CB job
    LTE is fragmented because spectrum is harder to find now as you're aware. You probably won't see a single global LTE band (or whatever it's called by then) unless an untapped frequency is decided upon and phones are designed to use it safely and efficiently. It's certainly possible but I can't say what that number would be.

    Seriously though...it would be nice if future US phones come with all major LTE bands (yes, including Sprint's...) But will Sprint and Verizon voluntarily open their LTE networks up to BYOP?
    If phones become truly universal then consumer demand could be the tipping point on convincing Red and Yellow to allow BYODs. LTE alone may be what does it for VZW sooner than later. As we all know, consumers are becoming smarter by way of the Internet. EE degrees are no longer needed for curious individuals to read and get a basic grasp on radio requirements. Social media would then become the catalyst.

    I agree that CDMA carriers won't likely go without a fight. Free market and consumer demand would have to prevail here.

    [CB10 / Q10]
    04-07-15 05:22 AM
  23. gariac's Avatar
    LTE is fragmented because spectrum is harder to find now as you're aware. You probably won't see a single global LTE band (or whatever it's called by then) unless an untapped frequency is decided upon and phones are designed to use it safely and efficiently. It's certainly possible but I can't say what that number would be.


    If phones become truly universal then consumer demand could be the tipping point on convincing Red and Yellow to allow BYODs. LTE alone may be what does it for VZW sooner than later. As we all know, consumers are becoming smarter by way of the Internet. EE degrees are no longer needed for curious individuals to read and get a basic grasp on radio requirements. Social media would then become the catalyst.

    I agree that CDMA carriers won't likely go without a fight. Free market and consumer demand would have to prevail here.

    [CB10 / Q10]
    But the CDMA carriers have gone LTE. So if I follow your thoughts here, you mean the old school CDMA carriers, basically Verizon, will never adopt BYOD. Probably true, because why should Verizon play nice when they have the most coverage.

    Even though our BlackBerry GSM phones can see Verizon LTE, I'm not holding my breath that we can ever roam on them.

    Posted via CB10
    lift likes this.
    04-07-15 11:54 AM
  24. modifier's Avatar
    But the CDMA carriers have gone LTE. So if I follow your thoughts here, you mean the old school CDMA carriers, basically Verizon, will never adopt BYOD. Probably true, because why should Verizon play nice when they have the most coverage.

    Even though our BlackBerry GSM phones can see Verizon LTE, I'm not holding my breath that we can ever roam on them.

    Posted via CB10
    Yeah, I'm just saying that CDMA carriers going LTE is what will help make devices universal. They've gone LTE but haven't yet gone VoLTE across the country. Once both GSM and CDMA carriers are on the same type of service, the only thing left will be individual flavors of spectrum. That's where devices could truly be universal. BB is already starting to include quite a number of bands and less sub-variants. The shift is beginning.

    Roaming across all carriers is likely a pipe dream since that's how the big two squeeze the little two and any associated MVNOs. But, that would certainly be easier from a device standpoint if all future devices include a complete number array of LTE bands.

    I'd love to see universal roaming. I hadn't even thought of that aspect until you mentioned it, mainly due to my pessimistic views on carriers playing in each others' sandboxes. Perhaps LTE will change that.

    Probably not.

    [CB10 / Q10]
    04-07-15 10:44 PM
  25. gariac's Avatar
    The problem with roaming, at least tmob on AT$T, is Tmob pays many times the retail cost for data. I don't recall the exact number. Tmob just wanted the charge to be retail, which sounds generous to me.


    Posted via CB10
    04-08-15 12:42 AM

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