Sprint LTE site IDs and signal metrics

[WiWavelength]

Tonight, I tracked four live LTE sites along the K-7 corridor in the western suburbs of Kansas City. The four sites from north to south are as follows:

• KC03XC117 (K-7 and 83rd St)
  
• KC03XC166 (K-7 and K-10)
  
• KC13XC367 (K-7 and 119th St)
  
• KC60XC066 (downtown Olathe)
  

Much like PN offsets, serving cell IDs are sequential, their trailing two digits following a clockwise pattern among the three sectors (N/SE/SW) on each site. The serving cell IDs for the three sectors of the four sites are as follows:

• 04C07D01/04C07D02/04C07D03
  
• 04C09001/04C09002/04C09003
  
• 04C13F01/04C13F02/04C13F03
  
• 04C1A901/04C1A902/04C1A903
  

Now that multiple, adjacent sites (rather than single, isolated sites) have gone live, very strong signal close in to a site with direct line of sight averages around -85 dBm RSRP and -6 dB RSRQ.

 

Finally, I intentionally drove out of the live LTE footprint to observe the fallback to eHRPD (EV-DO). I did this twice and observed that the drop threshold for LTE seems to be set approximately -123 dBm RSRP.

 

AJ

[pii100]

Wow 38db of margin before switching to ehrpd if my math is working this late.

[gr8nuguy]

that pretty impressive. That means i should get fairly good signal here in my basement, only being .8 miles from the tower

[Dkoellerwx]

I drove that same stretch this afternoon, but did not connect to LTE. Could it be they hadn't been switched on yet when I was there?

[WiWavelength]

that pretty impressive. That means i should get fairly good signal here in my basement, only being .8 miles from the tower

 

Perhaps, but I would not count on it in your basement. While driving on city streets through some moderately dense neighborhoods within a mile of the closest live LTE site, I was a bit underwhelmed by LTE signal strength and quality. On the other hand, CDMA1X and EV-DO were solid. So, LTE will likely be a bit more fragile than is EV-DO.

 

AJ

[WiWavelength]

I drove that same stretch this afternoon, but did not connect to LTE. Could it be they hadn't been switched on yet when I was there?

 

I had to cycle airplane mode in order to connect to LTE. Once I did, I retained LTE or quickly regained LTE as long as I stayed within the live LTE footprint.

 

AJ

[Dkoellerwx]

 

 

I had to cycle airplane mode in order to connect to LTE. Once I did, I retained LTE or quickly regained LTE as long as I stayed within the live LTE footprint.

 

AJ

 

I was cycling the CDMA/LTE - CDMA Only function, but it didn't seem to help. A couple hours later I did find several LTE towers on Prairie Star (95th) between Woodland and Lackman. Lost it as soon as I went north from there.

[WiWavelength]

I was cycling the CDMA/LTE - CDMA Only function, but it didn't seem to help. A couple hours later I did find several LTE towers on Prairie Star (95th) between Woodland and Lackman. Lost it as soon as I went north from there.

 

Well, Sprint does not have any sites along Prairie Star Pkwy. So, the only sites that you likely could have acquired are north along Renner Rd or south along Woodland Rd. But I cannot vouch that those sites have live LTE, as I did not venture that far east during my drive testing.

 

AJ

[Dkoellerwx]

I'd say its pretty close to Prairie Star

 

The next one was at 95th and 435, on the SE side of the intersection.

[WiWavelength]

I'd say its pretty close to Prairie Star

 

The next one was at 95th and 435, on the SE side of the intersection.

 

No, sorry, none of those are Sprint sites. That app (or the sites themselves) is not giving you accurate locations.

 

AJ

[Dkoellerwx]

Oh, huh. Certainly seemed to line up with an actual tower most of the time. Oh well.

[WiWavelength]

Oh, huh. Certainly seemed to line up with an actual tower most of the time. Oh well.

 

From my familiarity with the area, I can assure you that Sprint does not have sites where depicted on that app screen nor where you describe. Additionally, our interactive maps confirm my empirical observations. As a sponsor, you have access to many of our maps. Below is the link to the Kansas market site map:

 

http://s4gru.com/index.php?/topic/530-network-vision-site-map-arkansas-kansas-missouri-oklahoma-markets/

 

AJ

[boomerbubba]

No, sorry, none of those are Sprint sites. That app (or the sites themselves) is not giving you accurate locations.

 

AJ

 

Sounds like this market includes examples of towers that squawk offset coordinates for each sector, rather than simply the coordinates of the tower. Dkoellerwx's screen was obviouly from Netmonitor, which reports the coordinates the phone picks up from the base station broadcasts.

[wyndd123]

What app are u guys useing for the cell towers

[boomerbubba]

@WiWavelength:

 

What handset, operating system and application are you using to report the LTE signal strength?

[WiWavelength]

@WiWavelength:

 

What handset, operating system and application are you using to report the LTE signal strength?

 

I use HTC's own LTE Engineering screen. I am not a fan of third party apps for this purpose. Or, at least, I have never found any app particularly to my liking.

 

AJ

[boomerbubba]

I use HTC's own LTE Engineering screen. I am not a fan of third party apps for this purpose. Or, at least, I have never found any app particularly to my liking.

 

AJ

 

Thanks. Just to confirm, your handset is running Ice Cream Sandwich?

[WiWavelength]

Thanks. Just to confirm, your handset is running Ice Cream Sandwich?

 

Correct. However, HTC's FieldTrial.apk, which contains the various engineering screens, has not changed significantly since at least Froyo.

 

AJ

[boomerbubba]

Correct. However, HTC's FieldTrial.apk, which contains the various engineering screens, has not changed significantly since at least Froyo.

 

AJ

 

Thanks again. The reason I asked about Ice Cream Sandwich is that I have read various places that at the operating system and Android API level, which probably affects most applications, ICS devices report LTE dBm signals in a different manner than Gingerbread devices do, and the reported dBm might differ by about 10 dB. (This does not apply to EVDO or 1X levels.)

 

Do the dBm levels that the HTC FieldTrial app report for LTE signal match those reported under the Settings -> About Phone -> Etc..... screen?

[WiWavelength]

Thanks again. The reason I asked about Ice Cream Sandwich is that I have read various places that at the operating system and Android API level, which probably affects most applications, ICS devices report LTE dBm signals in a different manner than Gingerbread devices do, and the reported dBm might differ by about 10 dB. (This does not apply to EVDO or 1X levels.)

 

Do the dBm levels that the HTC FieldTrial app report for LTE signal match those reported under the Settings -> About Phone -> Etc..... screen?

 

boomerbubba, the issue is really a debate between two signal metrics: RSSI vs RSRP. Both use dBm as the unit of measurement, but they differ in ways that can make RSSI report signal levels ~25 dB greater than that of RSRP.

 

RSSI, which is a more traditional measurement that has long been used for various airlinks, measures all RF energy in the channel. RSRP, which is an LTE specific measurement, measures only the average power of many reference signals in the channel.

 

HTC's FieldTrial.apk reports RSRP (and RSRQ, but I will not go into that metric right now), while Android ICS may report RSSI. On the latter count, I am not sure. And I do not live within the current LTE footprint, so I cannot presently compare and contrast the reported signal levels. I can say that VZW has made a push to standardize RSSI for LTE signal reporting; thus, it would not surprise me if Android has followed that lead.

 

Due in part to your relevant questions, Robert and I have decided that now would be a good time to write up an article on LTE signal metrics. So, I will start working on turning this post into a full fledged article to be published on The Wall, ideally tomorrow afternoon.

 

AJ

[boomerbubba]

boomerbubba, the issue is really a debate between two signal metrics: RSSI vs RSRP. Both use dBm as the unit of measurement, but they differ in ways that can make RSSI report signal levels ~25 dB greater than that of RSRP.

 

RSSI, which is a more traditional measurement that has long been used for various airlinks, measures all RF energy in the channel. RSRP, which is an LTE specific measurement, measures only the average power of many reference signals in the channel.

 

HTC's FieldTrial.apk reports RSRP (and RSRQ, but I will not go into that metric right now), while Android ICS may report RSSI. On the latter count, I am not sure. And I do not live within the current LTE footprint, so I cannot presently compare and contrast the reported signal levels. I can say that VZW has made a push to standardize RSSI for LTE signal reporting; thus, it would not surprise me if Android has followed that lead.

 

Due in part to your relevant questions, Robert and I have decided that now would be a good time to write up an article on LTE signal metrics. So, I will start working on turning this post into a full fledged article to be published on The Wall, ideally tomorrow afternoon.

 

AJ

 

I look forward to that article. I must say, I was confused just looking at the RSRP LTE signal levels you reported in your original post, which to my untutored mind seemed surprisingly weak. But I am probably used to the RSSI signal levels more commonly reported for 3G and 1X.