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Thread: Threshold for phone switching to better signal cell

  1. #1
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    Threshold for phone switching to better signal cell

    So I get the fact that a cell carrier will put me onto a band that has more capacity than another band that may have greater signal strength or download speeds but less capacity. I get that. But what I don't get is why my phone will insist on staying with a band (like band 4) when signal strength is so poor that I am literally losing connections at -125db, and not change to a band (like band 12) with greater coverage that may be coming in at -110db or better.

    This seems to happen all the time. I see it using CellMapper to view the cell that I am connected to and the neighboring cells that I am not connected to.

    The threshold to change to a better signal appears to be set too high. Why does the signal strength need to be so poor that I am dropping calls before the switch is made? Maybe the phone should switch before getting to -125db or something?

    Is this just a Tmobile thing or do all the carriers work this way? Do any of the others switch before signal strength gets to -125db?

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    Quote Originally Posted by californiajay View Post
    So I get the fact that a cell carrier will put me onto a band that has more capacity than another band that may have greater signal strength or download speeds but less capacity. I get that. But what I don't get is why my phone will insist on staying with a band (like band 4) when signal strength is so poor that I am literally losing connections at -125db, and not change to a band (like band 12) with greater coverage that may be coming in at -110db or better.

    This seems to happen all the time. I see it using CellMapper to view the cell that I am connected to and the neighboring cells that I am not connected to.

    The threshold to change to a better signal appears to be set too high. Why does the signal strength need to be so poor that I am dropping calls before the switch is made? Maybe the phone should switch before getting to -125db or something?

    Is this just a Tmobile thing or do all the carriers work this way? Do any of the others switch before signal strength gets to -125db?
    At&t uses RSRQ to determine when to switch I believe. It goes by quality of the signal. It's usually somewhere around -110 dbm.

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    I have found this to be just like rush hour... i use iphone, sometimes the best thing to do is take off LTE and just hang around in 4G, sometimes is faster than LTE because like you said.. capacity.. but i found it to be true in rush hour.
    In android (not all) you can force all kinds of combos.. like 4G or LTE in certain bands. I hope this is still true, I havent use android in years.
    You can do this if you are stationary.. but if you are moving all over the city, just live it normal on both OS

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    Threshold depends on a few factors. At the least, there is a minimum for signal. Ive found through use and TMobiles upgrades (which pushed against mins). HSPA -113dBm, LTE band 2 -120dBm (may have changed), band 12 -126dBm and band 4 -140dBm

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    AT&T... your world, throttled.

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    Here is an area where TMobile claims only band12... But i can only get band 4 Name:  1555794084251.jpg
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Size:  34.4 KB

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    Quote Originally Posted by formercanuck View Post
    Threshold depends on a few factors. At the least, there is a minimum for signal. Ive found through use and TMobiles upgrades (which pushed against mins). HSPA -113dBm, LTE band 2 -120dBm (may have changed), band 12 -126dBm and band 4 -140dBm
    I want to change this to -110. -140 is just silly. Anything below around -122 that my phone reports is pretty much unusable for me. I was breaking up on a call this morning before it switched to the tower almost right in front of me. I know the carriers seek to minimize switching, but this is ridiculous, especially if it continues as B71 continues to roll-out.

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    Quote Originally Posted by Falcon_73 View Post
    I want to change this to -110. -140 is just silly. Anything below around -122 that my phone reports is pretty much unusable for me. I was breaking up on a call this morning before it switched to the tower almost right in front of me. I know the carriers seek to minimize switching, but this is ridiculous, especially if it continues as B71 continues to roll-out.
    You can file a ticket, as I did. You will have to get past the first level or 2 of techs to get someone that actually knows what they're talking about. It took an escalation or 2 to tell them that I had 1 bar outside my house at -118dBm when I was 1000' away from the nearest cell, and speed test was failing to connect. TMobile engineers were able to drop the handoff threshold to -116 (or -114dBm) and then it handed off from band 2 of 3 miles away to band 4 1000' away.

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    Quote Originally Posted by Falcon_73 View Post
    I want to change this to -110. -140 is just silly. Anything below around -122 that my phone reports is pretty much unusable for me. I was breaking up on a call this morning before it switched to the tower almost right in front of me. I know the carriers seek to minimize switching, but this is ridiculous, especially if it continues as B71 continues to roll-out.
    This is exactly my point. 2 days ago, I literally couldn't understand a word from a friend who on Tmobile was breaking up so badly, I finally just had to hang up after telling him (and hoping he could hear me) that his phone was breaking up and I couldn't hear anything he was saying. The other night, my wife kept dropping calls along a major Southern California freeway. She has told me so many times that she wants to go back to AT&T and is about to do so. Every now and then I must take her for appointments at a Kaiser in the area. There is absolutely no coverage whatsoever inside that building, none...even though there is a Tmobile tower considerably closer to the building than a Verizon tower. But I see people inside the waiting room using Verizon like there is no problem at all.

    It just seems as though, even though Tmobile is doing so much to deploy 600mhz, they are reluctant to let anyone actually use it. I have been through 600mhz areas many times now, never once having connected to a 600mhz signal, even when my phone was over -120db.
    What exactly is the point of owning the spectrum? Was it just to hold for 5G.

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    Just an update:
    This morning I am seeing anywhere between -105 and -120db on my normal band 4 connection, which usually comes in around -87db. Download speeds are at 0.01mbps on band 4 and I cannot access any data from my apps. Apparently, whatever they have done or are doing right now has killed that band. Hopefully it is temporary.
    According to Cellmapper, there is a -85db signal on band 12 from the same tower. For the umpteenth time, I ask why the phone insists on staying connected to band 4. It's getting old.

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    Quote Originally Posted by formercanuck View Post
    You can file a ticket, as I did. You will have to get past the first level or 2 of techs to get someone that actually knows what they're talking about. It took an escalation or 2 to tell them that I had 1 bar outside my house at -118dBm when I was 1000' away from the nearest cell, and speed test was failing to connect. TMobile engineers were able to drop the handoff threshold to -116 (or -114dBm) and then it handed off from band 2 of 3 miles away to band 4 1000' away.
    Thanks, I will give it a try.

    And yes, this is getting old. It's not the days where it was pretty much just B4 for LTE. This shouldn't be so hard! I once had a Nokia Windows Phone that would allow me to disable bands. Wish I had that now.

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    Quote Originally Posted by Falcon_73 View Post
    Thanks, I will give it a try.

    And yes, this is getting old. It's not the days where it was pretty much just B4 for LTE. This shouldn't be so hard! I once had a Nokia Windows Phone that would allow me to disable bands. Wish I had that now.
    My LG has something similar. I can select a specific band.

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    Another update:
    This morning, I've got an AT&T SIM card in my phone. What I am seeing is eye opening. What AT&T seems to do different from Tmobile is that it will select the band to use based primarily on signal strength and secondly, signal quality (RSRQ). During the past hour of monitoring this, I have only seen once where the phone was not connected to the band with the best signal strength and that was the one time in which the second best had a noticeably higher RSRQ. Every other time, as I look down the list of neighboring cells in Cellmapper, the signal strength gets lower and lower on down the list. With Tmobile, more often than not the cell with the best signal (and even one or two more) will just not be chosen to connect to. It just seems to prefer band 4 no matter what, unless the signal strength is so bad that it becomes completely useless.
    I am tempted to give tier 2 tech support a call and give that a try as suggested, or just switch to AT&T.

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    So I spoke with tier 2 tech support. They had me once again run through some routine stuff which I knew wasn't going to accomplish anything but did so anyway.
    Bottom line is that it seems Tmobile's network chooses which band is to be used and unless the phone allows that to be overridden, it just will not change. It's selection seems to be based on certain prority bands, network congestion, and lastly signal strength. AT&T seems to put the highest priority on signal strength.
    What I did see this morning as I was talking with the tech support rep was that the phone did go to band 12 during the call, but only during the call. You may say that this is all well and good since it insures that a better signal is used during the call, however I would say well yes, but if it's on a band with -125db waiting for a call, the phone may never even ring since the reception is so bad. I HAVE actually had that happen to me a couple of times.

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    Verizon will often switch to a stronger Band 13 during a call, then switch back to a weaker Band 4 when idle.
    Check out my Reno Area Wireless Information & Cellular Guide website for cell site location maps, pictures & more https://RenoWirelessInfo.com

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    Quote Originally Posted by RenoWirelessGuru View Post
    Verizon will often switch to a stronger Band 13 during a call, then switch back to a weaker Band 4 when idle.
    T-Mobile must have some form of band preference, I just don't know what they are using. +90% of the time, it is on either band 4 or 2. Once in a while it will camp on band 12, but pretty rarely. If it was using RSRP, it would be on band 12 the majority of the time. Band 4 and 2 have similar RSRP/RSRQ where I am, while band 12 has close to -10dBm better signal and 3-4dBm better RSRQ.
    With band 12 having only 5MHz of spectrum, I suspect that they have methods to 'not use' band 12 often (i.e. unless band 4 / 2 go beyond a certain level). Band 2 typically has to be worse than ~-120dBm. Band 4, I'm not sure, but the threshold for service is -140dBm.

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