bmoses Posted August 20, 2015 Share Posted August 20, 2015 Yes. A -88 dBm signal is almost four times stronger than a -93 dBm signal. Other factors besides RSRP -- such as RSRQ, SINR, and MIMO -- may have changed in that distance. For a 5 MHz FDD band 25 carrier at 3 miles distance from the serving site, that should be cell edge, and 5 Mbps would be great speeds, honestly. AJ wow..... that just blows my mind that it really is that fragile. i would have thought you wouldn't start seeing 5 meg or less until -105 or worse. i assume the curve drops fast and then trails off from there? i ask because i'm sitting at -107 and 4.4SNR right now and just pulled 3 meg down. this is from the same tower that i was referencing in the above scenario. Quote Link to comment Share on other sites More sharing options...
WiWavelength Posted August 20, 2015 Share Posted August 20, 2015 i assume the curve drops fast and then trails off from there? Exactly. The path loss is exponential/logarithmic. Even with direct line of sight, a 20 W signal, for example, has already been attenuated to milliwatts just 100 m from the antenna. AJ 1 Quote Link to comment Share on other sites More sharing options...
Stew503 Posted August 20, 2015 Share Posted August 20, 2015 Exactly. The path loss is exponential/logarithmic. Even with direct line of sight, a 20 W signal, for example, has already been attenuated to milliwatts just 100 m from the antenna. AJ I get -114 on B41 in my living room and get 20mb down. If I step outside I get 60mb down. Sent from my LGLS991 using Tapatalk Quote Link to comment Share on other sites More sharing options...
bmoses Posted August 20, 2015 Share Posted August 20, 2015 I get -114 on B41 in my living room and get 20mb down. If I step outside I get 60mb down. Sent from my LGLS991 using Tapatalk that would be the difference between a 20 mhz pipe on B41 and a 5 mhz pipe on B25. plus B41 is using beamforming and what not that improves edge of cell performance. Quote Link to comment Share on other sites More sharing options...
bretton88 Posted August 23, 2015 Share Posted August 23, 2015 amen to this! optimization needs to happen so bad around here (here being des moines)! and not just cranking up the power on B26 and optimizing it, B25 needs it too. i find places all over the metro (on B25) where running a speedtest near a tower nets a 20+ meg download yet going down the road a bit will drop you down to 5 meg or less. i'm convinced that the rootmetrics report speeds were more due to bad optimization affecting the results then they were from towers being overloaded.It's more that there are still a lot of drops to 3G, especially here in eastern Iowa in areas that B26 should be able to cover. I really hate not being able to hold onto a -112 B25 signal and dropping to 3G, it happens a lot here in cedar rapids. 1 Quote Link to comment Share on other sites More sharing options...
RAvirani Posted August 23, 2015 Share Posted August 23, 2015 It's more that there are still a lot of drops to 3G, especially here in eastern Iowa in areas that B26 should be able to cover. I really hate not being able to hold onto a -112 B25 signal and dropping to 3G, it happens a lot here in cedar rapids. Yea if only our phones held on to weak LTE like -112... Quote Link to comment Share on other sites More sharing options...
payturr Posted August 23, 2015 Share Posted August 23, 2015 Yea if only our phones held on to weak LTE like -112... They do. Technically they should be able to hold onto LTE signals as low as -130. I've seen a friend's phone on VZW do it before. If the phone drops after -112, it's the phone's software holding it back. 1 Quote Link to comment Share on other sites More sharing options...
BlueAngel Posted August 23, 2015 Share Posted August 23, 2015 They do. Technically they should be able to hold onto LTE signals as low as -130. I've seen a friend's phone on VZW do it before. If the phone drops after -112, it's the phone's software holding it back. I used to be able to hold onto B41 down to around ~125dBm but now it cuts off after maybe ~114dBm it really sucks. B41 is more than usable at that signal strength. Quote Link to comment Share on other sites More sharing options...
payturr Posted August 24, 2015 Share Posted August 24, 2015 I had usable B41 this morning at -132. That was something. 1 Quote Link to comment Share on other sites More sharing options...
Fraydog Posted August 24, 2015 Share Posted August 24, 2015 I had usable B41 this morning at -132. That was something. 8T8R? Anyway, that's impressive considering that -120 cuts off LTE for a lot of devices. Quote Link to comment Share on other sites More sharing options...
RAvirani Posted August 24, 2015 Share Posted August 24, 2015 8T8R? Anyway, that's impressive considering that -120 cuts off LTE for a lot of devices. I mean I've seen devices hold on as low as -140 LTE but the programming doesn't let them normally. I really wish the phone programming had it holding on until ~130 or so because LTE on B41 is still very usable at that signal. From my experience, 1900 is good until about -120 too. Quote Link to comment Share on other sites More sharing options...
SkyGuy98 Posted August 30, 2015 Share Posted August 30, 2015 It's more that there are still a lot of drops to 3G, especially here in eastern Iowa in areas that B26 should be able to cover. I really hate not being able to hold onto a -112 B25 signal and dropping to 3G, it happens a lot here in cedar rapids. Yea if only our phones held on to weak LTE like -112... They do. Technically they should be able to hold onto LTE signals as low as -130. I've seen a friend's phone on VZW do it before. If the phone drops after -112, it's the phone's software holding it back. That's Iowa for you- widespread (but slow) 3G EV-DO that penetrates everywhere, and spotty but fast LTE B25/26 (When you can catch it). I wish we could keep the signal for longer, but the towers need lots of tuning and good 'ol Apple loves our batteries too much to let us use a weak LTE signal *Sigh* . Quote Link to comment Share on other sites More sharing options...
bucdenny Posted August 31, 2015 Share Posted August 31, 2015 I mean I've seen devices hold on as low as -140 LTE but the programming doesn't let them normally. I really wish the phone programming had it holding on until ~130 or so because LTE on B41 is still very usable at that signal. From my experience, 1900 is good until about -120 too. The problem is you need a functional upload connection on LTE. If it ain't functional you won't be able to receive any calls on a tri-band device. Quote Link to comment Share on other sites More sharing options...
RAvirani Posted August 31, 2015 Share Posted August 31, 2015 The problem is you need a functional upload connection on LTE. If it ain't functional you won't be able to receive any calls on a tri-band device. That's Iowa for you- widespread (but slow) 3G EV-DO that penetrates everywhere, and spotty but fast LTE B25/26 (When you can catch it). I wish we could keep the signal for longer, but the towers need lots of tuning and good 'ol Apple loves our batteries too much to let us use a weak LTE signal *Sigh* . I have AT&T iPhones and I see them holding LTE as far as -125 on B17, functioning fine... Quote Link to comment Share on other sites More sharing options...
bucdenny Posted August 31, 2015 Share Posted August 31, 2015 I have AT&T iPhones and I see them holding LTE as far as -125 on B17, functioning fine... AT&T doesn't use CDMA for voice. Sprint Triband LTE devices uses Circuit Switched Fallback (CSFB) to fallback on CDMA. If you don't have a working data connection (download and upload) on weak LTE signal... your SOL on an incoming voice call. B41 with RSRP of -125 which I have experienced myself issues with incoming calls because of a weak LTE signal that needs to be able to communicate back to the network. Here is an article on CSFB which Sprint is dependent on for voice functionality: http://s4gru.com/index.php?%2Fblog%2F1%2Fentry-357-nexus-5-and-lg-g2-experience-temporary-sprint-lte-connectivity-issues-due-to-circuit-switched-fallback-technology%2F Quote Link to comment Share on other sites More sharing options...
RAvirani Posted September 1, 2015 Share Posted September 1, 2015 AT&T doesn't use CDMA for voice. Sprint Triband LTE devices uses Circuit Switched Fallback (CSFB) to fallback on CDMA. If you don't have a working data connection (download and upload) on weak LTE signal... your SOL on an incoming voice call. B41 with RSRP of -125 which I have experienced myself issues with incoming calls because of a weak LTE signal that needs to be able to communicate back to the network. Here is an article on CSFB which Sprint is dependent on for voice functionality: http://s4gru.com/index.php?%2Fblog%2F1%2Fentry-357-nexus-5-and-lg-g2-experience-temporary-sprint-lte-connectivity-issues-due-to-circuit-switched-fallback-technology%2F Also, AT&T falls back to HSPA+ to take calls and since I see DBMs like -125 on AT&T LTE a lot and calls go through just fine, their phones must be able talk to the network just fine. Maybe it's that lower frequencies like B17 (700mhz) work better at those DBMs? Quote Link to comment Share on other sites More sharing options...
anthony.spina97 Posted September 1, 2015 Share Posted September 1, 2015 Also, AT&T falls back to HSPA+ to take calls and since I see DBMs like -125 on AT&T LTE a lot and calls go through just fine, their phones must be able talk to the network just fine. Maybe it's that lower frequencies like B17 (700mhz) work better at those DBMs?Or the fact that AT&T uses 10 MHz wide carriers rather than 5 Mhz wide carriers. -Anthony Quote Link to comment Share on other sites More sharing options...
RAvirani Posted September 1, 2015 Share Posted September 1, 2015 Or the fact that AT&T uses 10 MHz wide carriers rather than 5 Mhz wide carriers. -Anthony But we use 20mhz B41? Quote Link to comment Share on other sites More sharing options...
Fraydog Posted September 1, 2015 Share Posted September 1, 2015 Or the fact that AT&T uses 10 MHz wide carriers rather than 5 Mhz wide carriers. -Anthony In some parts of America people are detecting AT&T using 15x15 using PCS. 1 Quote Link to comment Share on other sites More sharing options...
anthony.spina97 Posted September 1, 2015 Share Posted September 1, 2015 But we use 20mhz B41? Yes, but TDD works differently than FDD. The problem that users on Sprint have with 20 MHz B41, which is TDD, the theoretical max upload speeds are lower than that of a 10 MHz B17 carrier. Which means that when at cell edge, say -125 dBm like you used in your example, the 10 MHz FDD carrier will have a higher upload speed than the 20 MHz TDD carrier, which means the FDD carrier can communicate to the tower better than the TDD carrier can. You could use the argument that one is 700 MHz vs 2.5/2.6 GHz so one propagates much better than the other, but when you're talking in terms of when either signal is -125 dBm, IIRC, they are at an equally terrible signal strength, so both perform the same (if they were both using the same LTE technology). -Anthony 2 Quote Link to comment Share on other sites More sharing options...
RAvirani Posted September 2, 2015 Share Posted September 2, 2015 Yes, but TDD works differently than FDD. The problem that users on Sprint have with 20 MHz B41, which is TDD, the theoretical max upload speeds are lower than that of a 10 MHz B17 carrier. Which means that when at cell edge, say -125 dBm like you used in your example, the 10 MHz FDD carrier will have a higher upload speed than the 20 MHz TDD carrier, which means the FDD carrier can communicate to the tower better than the TDD carrier can. You could use the argument that one is 700 MHz vs 2.5/2.6 GHz so one propagates much better than the other, but when you're talking in terms of when either signal is -125 dBm, IIRC, they are at an equally terrible signal strength, so both perform the same (if they were both using the same LTE technology). -Anthony What time ratio does sprint use for TD-LTE? Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.