by Robert Herron
Sprint 4G Rollout Updates
Wednesday, July 18, 2012 - 12:59 PM MDT
As many of you already know, the ability to connect and keep connected to LTE signals in Sprint's launch markets has been problematic for Sprint customers. What's going on?
Here at our forums at S4GRU, we have been busy talking with our members and trying to figure out the issue since LTE markets started going live last Thursday. Some members were able to connect early and often. Some had problems and were able to eventually connect. Some have been unable to stay connected. Some have never connected, even standing right next to a live LTE site.
We have now complied a lot of data from our members and have drawn some observational conclusions. There are two main issues, connecting to LTE can be a challenge on some devices (especially the EVO LTE), and the signal thresholds are not optimum to keep connected to LTE before getting pushed back to the 3G EVDO network.
I am in a confirmed LTE area with a strong signal but cannot connect
Some LTE devices just do not want to connect to LTE. With the EVO LTE, some of our members have complained that they even stood next to a confirmed operating LTE site and the 4G icon would not appear. For most of these folks though, cycling from CDMA/LTE mode, back to CDMA only mode and then back to CDMA/LTE mode forces the phone to look for a LTE signal. This has worked for most people I have talked with who have an EVO LTE and know they are in a strong LTE signal area. This also seems to help some other LTE devices sometimes.
There most likely is an issue where these devices are not scanning for LTE service like they should be. When you go out of CDMA/LTE mode and then come back in, the first thing the device does is scan for LTE service. Hopefully, Sprint will get an OTA out that fixes this issue soon.
I can connect to LTE but it goes back to 3G EVDO
Other members have discussed how they can connect to 4G LTE, whether automatically or by forcing it (as described above), but it goes back to 3G EVDO. They cannot keep a Sprint LTE connection. This may happen right away, or this may happen as they drive down the road, or after they pick up the device.
By the best we can tell, this is being caused by the LTE signal thresholds programmed in the device(s). When your device is in CDMA/LTE mode, it seeks LTE first. If it finds LTE, it should connect, but if it doesn't have a strong enough signal, it shunts the user off to 3G, sometimes in seconds. The devices have a minimum LTE signal programmed in them (it appears to be somewhere in the midrange and could be slightly different between devices).
If the LTE minimum signal that is programmed is maintained, the device stays connected to LTE, no problems in most instances. So if you have a strong LTE signal after you connect, you will most likely keep it. However, if you have a midrange LTE signal, you will likely get bumped back down to 3G EVDO if you should move farther away from the signal, or maybe even pick up the device. Most devices will drop a few dBm of signal when being held, and it could be enough to move you back down to 3G.
If you have a weak LTE signal, then you are almost doomed. You will not likely be able to stay connected to LTE for very long and most likely be shunted back to 3G pretty quickly. An exception to this we noted is if you are also in a weak 3G area. But if you have a strong 3G signal and a weak LTE signal, you are most likely not going to be able stay connected with the current thresholds programmed.
What can Sprint do?
I know this is very frustrating for most of you. We all want it to work flawlessly. But this is part of the process. Sprint needs our constructive feedback so they can make changes. There are drawbacks to being early adopters.
That is the point of this article. To wrap up some meaningful and thoughtful feedback from our members into a single comprehensive piece and give to Sprint for them to work on. As well as educate our members and readers into some of the information we have been able to determine.
Sprint, please work with your OEM's right away on OTA's to adjust the thresholds for keeping LTE signals, as well as addressing the cycling through CDMA only mode to get devices to make initial LTE connection. One key point that I hear over and over again is that LTE customers would rather have a weak LTE signal than a strong 3G signal. Weak LTE still performs better than even good 3G in most instances.
If anyone from Sprint would like to reach out to me and provide any updates of what they are doing to address the problem, I would love to receive a PM, email or Direct Message on Twitter. I will then be happy to provide an update for our members and readers.
What can we do now?
With WiMax devices, we could actually change the WiMax signal threshold ourselves. However, we have not been able to locate anywhere in the LTE devices where that can be done. So we are in a waiting position to see if Sprint will help us.
If you absolutely cannot connect to LTE or stay connected to LTE, you can force your device into LTE only mode. If you do this, you will lose access to 3G EVDO and 1x services while in this mode. But it is reversible at any time. It requires your device's MSL code, though. You can get your MSL code by using some apps like MSL Reader, or by using a Terminal Emulator with some models. You can search the web for ways to get your MSL code of your particular device. Some people can even get it from Sprint CSR's.
Once you have your MSL code, go into your phone dialer and enter ##DATA# (*#*#DATA#*#* on the Galaxy Nexus). A menu will open and ask you to select Edit or View. Select Edit. Enter your MSL number. Now in each device, there may be some variability in the next steps. Select the Others button, then choose HDR/1X selection. Select LTE Only mode. Now you will only be able to connect to LTE, no 3G or 1x. However, you will not be able to make/receive phone calls or text in this mode. Data only.
Once in LTE Only mode, you will only be able to connect to LTE signals. Even weak LTE signals. And you will not have to worry about getting shoved off into 3G. This will allow you to test your LTE, and make sure your LTE is indeed working in your device. You could stay parked in this mode if you wanted to. You just wouldn't be able to use the phone or text. To restore to normal, just go back in the same way and select LTE/CDMA or LTE/CDMA/EVDO, depending on your device.
If going into LTE only mode you are still unable to connect to LTE, then you are either not in LTE coverage like you thought you were, or your device has a problem.
This is all we know at this time. We will update with more information as we learn it. Thank you to all who helped gather this information from the field. You guys are what make S4GRU an awesome place!