Discussion on Device selection of 800MHz Carriers

[Zander]

There are bunch of towers by me that should have a 800Mhz band in north Chicago suburbs but still my phone only sees Band 1.I Think channel 775. GALAXY 3 has SMR support most likely 800 is off. Can't wait to try it out. I think SMR should be channel 476 Band 10.

[S4GRU]

 

There are bunch of towers by me that should have a 800Mhz band in north Chicago suburbs but still my phone only sees Band 1.I Think channel 775. GALAXY 3 has SMR support most likely 800 is off. Can't wait to try it out. I think SMR should be channel 476 Band 10.

 

800 is a lower priority. You only need it when you have a low 1900 signal, like inside a basement or far away from a tower. Your device will only scan for 800 SMR CDMA when the 1900 CDMA carrier have a poor EcIo ratio.

 

There are testing PRL's you can install that will force scan for 800 carriers. You can download one of these to see if 800 Channel 476 is being broadcast in your area. But these PRL's would not be good as a daily driver. We have one in the S4GRU DL Center.

 

Robert via CM9 Kindle Fire using Forum Runner

[TheForce627]

When I connect to channel 476 on my gnex it shows band class 0. I know it should be 10 but I wonder why it doesnt show it

[ipatella]

800 is a lower priority. You only need it when you have a low 1900 signal, like inside a basement or far away from a tower. Your device will only scan for 800 SMR CDMA when the 1900 CDMA carrier have a poor EcIo ratio.

 

There are testing PRL's you can install that will force scan for 800 carriers. You can download one of these to see if 800 Channel 476 is being broadcast in your area. But these PRL's would not be good as a daily driver. We have one in the S4GRU DL Center.

 

Robert via CM9 Kindle Fire using Forum Runner

 

Robert the sheer amount of information I learn from you is amazing.

 

So with LTE and EVDO-A being on 1900 I can expect the same amount of bars at all locations I'm currently having trouble with, correct?

[ydoucare]

I'm just wondering what kind of threshold there will be for 1900 that will allow the phone switch to 800, for example, is it going to try to hang on for dear life to 1900? The 1900 signal can fluctuate quite a bit for me at home, anywhere from -85ish to -100.

[tongboy]

I'm just wondering what kind of threshold there will be for 1900 that will allow the phone switch to 800, for example, is it going to try to hang on for dear life to 1900? The 1900 signal can fluctuate quite a bit for me at home, anywhere from -85ish to -100.

 

My personal experience with my evo lte is you need to loose pretty much all the pcs signal before it switches to the SMR band. Once my phone acquired the SMR band it held onto it for a while even when I moved into an area that I could get pcs. Eventually it switched back.

 

Sent from my EVO LTE

[CriticalityEvent]

Robert the sheer amount of information I learn from you is amazing.

 

So with LTE and EVDO-A being on 1900 I can expect the same amount of bars at all locations I'm currently having trouble with, correct?

I'm just wondering what kind of threshold there will be for 1900 that will allow the phone switch to 800, for example, is it going to try to hang on for dear life to 1900? The 1900 signal can fluctuate quite a bit for me at home, anywhere from -85ish to -100.

My personal experience with my evo lte is you need to loose pretty much all the pcs signal before it switches to the SMR band. Once my phone acquired the SMR band it held onto it for a while even when I moved into an area that I could get pcs. Eventually it switched back.

 

Sent from my EVO LTE

 

 

Check this thread out!

 

http://s4gru.com/ind...at-signal-edge/

 

 

/shameless self-promotion

[digiblur]

 

800 is a lower priority. You only need it when you have a low 1900 signal, like inside a basement or far away from a tower. Your device will only scan for 800 SMR CDMA when the 1900 CDMA carrier have a poor EcIo ratio.

 

There are testing PRL's you can install that will force scan for 800 carriers. You can download one of these to see if 800 Channel 476 is being broadcast in your area. But these PRL's would not be good as a daily driver. We have one in the S4GRU DL Center.

 

Robert via CM9 Kindle Fire using Forum Runner

 

Actually this is not true anymore in the 24xxx/25xxx PRL series. So for now it looks like they are letting the LTE devices use 800SMR band first. I am sure this will change later though.

 

Sent from my C64 w/Epyx FastLoad Cartridge

[S4GRU]

 

Actually this is not true anymore in the 24xxx/25xxx PRL series. So for now it looks like they are letting the LTE devices use 800SMR band first. I am sure this will change later though.

 

Sent from my C64 w/Epyx FastLoad Cartridge

 

This makes sense in Chicago. Since Chicago is a spectrum constrained market, they need the extra carrier for offload. However, they will likely have it be different in other markets as they start adding them to the PRL's. And eventually they will have to make the adjustment for Chicago too. Otherwise, people in basements and edge of service will not be able to get on an 800 carrier because it will be already full of people who are well within 1900 coverage, but hogging the 800.

 

Robert via CM9 Kindle Fire using Forum Runner

[WiWavelength]

Otherwise, people in basements and edge of service will not be able to get on an 800 carrier because it will be already full of people who are well within 1900 coverage, but hogging the 800.

 

That could be. However, Sprint could allow mobiles to idle on the SMR 476 CDMA1X carrier channel but set up traffic channels on PCS CDMA1X carrier channels for those mobiles that are well within range of PCS 1900 MHz propagation.

 

AJ

[S4GRU]

That could be. However, Sprint could allow mobiles to idle on the SMR 476 CDMA1X carrier channel but set up traffic channels on PCS CDMA1X carrier channels for those mobiles that are well within range of PCS 1900 MHz propagation.

 

AJ

 

Hmm. This is a concept I am unfamiliar with. Maybe you can expand a little on that for us when you get a chance.

 

Robert

[WiWavelength]

Hmm. This is a concept I am unfamiliar with. Maybe you can expand a little on that for us when you get a chance.

 

A mobile invokes the hashing algorithm -- as I described in my recent article -- for idle carrier channel selection. Then, the mobile sends/receives all access/paging traffic on that CDMA1X carrier channel. But for actual CDMA1X voice/data traffic, the base station controller (BSC) can decide to set up that voice/data traffic on a different CDMA1X carrier channel and redirect the mobile to that channel. The BSC can make the determination to redirect the mobile to a different CDMA1X carrier channel because of differences in carrier channel loading. For example, the BSC might redirect a mobile with high path loss to a more lightly loaded CDMA1X carrier channel because that could allow the mobile to reduce its transmit power. After its voice/data traffic ceases, the mobile then rehashes back to its original CDMA1X carrier channel.

 

Does that make sense so far?

 

AJ

[S4GRU]

A mobile invokes the hashing algorithm -- as I described in my recent article -- for idle carrier channel selection. Then, the mobile sends/receives all access/paging traffic on that CDMA1X carrier channel. But for actual CDMA1X voice/data traffic, the base station controller (BSC) can decide to set up that voice/data traffic on a different CDMA1X carrier channel and redirect the mobile to that channel. The BSC can make the determination to redirect the mobile to a different CDMA1X carrier channel because of differences in carrier channel loading. For example, the BSC might redirect a mobile with high path loss to a more lightly loaded CDMA1X carrier channel because that could allow the mobile to reduce its transmit power. After its voice/data traffic ceases, the mobile then rehashes back to its original CDMA1X carrier channel.

 

Does that make sense so far?

 

AJ

 

Perfect sense. I know it may be hard to believe, but I did not know this. Thanks.

 

Robert

[WiWavelength]

Perfect sense. I know it may be hard to believe, but I did not know this. Thanks.

 

While carrier channel redirection is fairly standard network management, I am just thinking aloud how Sprint might apply that to CDMA1X 800. What I suggest could be way off. I will elaborate further in my next post.

 

AJ

[WiWavelength]

To continue where I left off last night, Sprint might -- and I do stress might -- decide to have all mobiles idle on SMR 476 (or SMR 526 in markets with other ESMR incumbents). Even though voice traffic is not the primary focus that it once was, voice traffic could still overwhelm the single CDMA1X 800 carrier. So, when setting up a traffic channel, a Sprint BSC could use open loop power estimation (e.g. 800 MHz > 1900 MHz by ~7 dB) to determine if a particular mobile would have sufficient signal strength to support the traffic channel on CDMA1X 1900 instead. If so, the BSC would redirect the mobile to a traffic channel on one of several CDMA1X 1900 carriers. Conversely, if the mobile would lack sufficient signal strength to carry the traffic channel at PCS 1900 MHz, the BSC would set up the traffic channel on the single CDMA1X 800 carrier.

 

Why might Sprint do this? Psychology. Most subs judge signal strength not by actual ability to make/receive calls but by number of signal bars on their idle handsets as they move about during their daily lives. If Sprint were to push out new PRLs and have all band class 10 capable handsets idle on CDMA1X 800, that would be an immediate booster shot for signal strength -- whether measured by signal bars or dBm -- and could help to improve Sprint's perception as a carrier with strong coverage.

 

AJ

[WiWavelength]

To add yet a few more thoughts, Sprint could have mobiles all camp on CDMA1X 800 with selective traffic channel redirection to CDMA1X 1900 on a market by market basis. For example, digiblur's Baton Rouge former Gulf Coast PCS affiliate market -- with its wildly optimistic site spacing -- would be a great candidate to have mobiles idle on CDMA1X 800 at all times. Sprint could accomplish this by way of new PRLs or via idle mobile redirection.

 

Speaking of idle mobile redirection, if anyone is interested, ask me about the PCS 1900 MHz "bridge" that VZW engineered, using idle mobile redirection to CDMA1X 1900 across a boundary between two VZW Cellular 850 MHz A block and B block licenses. It was an idea that I formulated years ago but have found realized only once.

 

Also, as this discussion is running far afield from Chicago, we may want to "redirect" it to a new thread. Or it might warrant a technical article on The Wall.

 

AJ

[ragweed03]

After reading this interesting thread I started wondering if by some chance I have picked up on a 800 Mhz signal on my Evo 4G LTE. I noticed that Robert stated, "You only need it when you have a low 1900 signal, like inside a basement or far away from a tower. Your device will only scan for 800 SMR CDMA when the 1900 CDMA carrier have a poor EcIo ratio." Well for instance, I am at work right now and in the direct center of the building. I am in a room with no windows in the center of the building. Around the outside of the room is a hallway lined with offices with windows. I get one bar of Sprint with a -105 dBm signal to two bars of MetroPCS or Verizon signal with a signal of -100 to -103 dBm. With that said, tongboy stated earlier, "My personal experience with my evo lte is you need to loose pretty much all the pcs signal before it switches to the SMR band. Once my phone acquired the SMR band it held onto it for a while even when I moved into an area that I could get pcs. Eventually it switched back." I guess there is no 800 mHz signal on towers in downtown Fort Worth or for some reason my phone just isn't connecting to it. Any thoughts?

[iansltx]

Another piece of food for thought: better signal in 800 should make for decreased transmit power requirements, right? And switching idle carriers due to low signal would use up more power as well.

 

So if Sprint pushes out a PRL that, for all phones with SMR CDMA support, keeps those phones idling on the SMR channel when possible, those devices end up using marginally less power than if they idled at PCS. They would also be less likely to miss calls/texts due to coverage holes, though this is balanced by the finite amount of paging space on a single CDMA 1x carrier I suppose. Calls would still end up on a PCS carrier whenever possible, but battery life should be positively impacted.

 

AJ, correct me if I'm far afield on my understanding of the system or its ramifications. Also, I assume that I'm visualizing the VZW A-PCS-B bridge/idle carrier selection process correctly but elaboring about it wouldn't hurt...though it probably should be in another thread

 

Side note: I wonder how much capacity a 1x channel has for SMS messages. I assume one per slot cycle per code (so around 34 per slot cycle overall?), but I could be very wrong here.

[S4GRU]

I guess there is no 800 mHz signal on towers in downtown Fort Worth or for some reason my phone just isn't connecting to it. Any thoughts?

 

So far, there is only CDMA 800 confirmed deployed by Sprint in the Chicago market. We list those sites in the NV Sites Complete thread. We have also had member reported sightings of 800 in Baltimore, DC and LA. But these have not been accepted complete from Sprint, yet.

 

Robert

[Kevster1321]

 

 

So far, there is only CDMA 800 confirmed deployed by Sprint in the Chicago market. We list those sites in the NV Sites Complete thread. We have also had member reported sightings of 800 in Baltimore, DC and LA. But these have not been accepted complete from Sprint, yet.

 

Robert

Do you know if the latest prl has 800mhz for all markets or just Chicago market.

[S4GRU]

Do you know if the latest prl has 800mhz for all markets or just Chicago market.

 

The last PRL update I'm aware of only included 800 1x support in Chicago and Dallas. But we have yet to see any confirmation of live CDMA 800 in DFW, yet.

 

Robert

[digiblur]

Do you know if the latest prl has 800mhz for all markets or just Chicago market.

 

Chicago and Dallas only.

[Kevster1321]

Thanks

[ydoucare]

800 has been active again here for the past few days and when it is active, my phone never switches to 1900, it's always 800 no matter what I do.

[WiWavelength]

800 has been active again here for the past few days and when it is active, my phone never switches to 1900, it's always 800 no matter what I do.

 

I may stand vindicated.

 

 

AJ