No simultaneous voice and date on iPhone 5?

I have recently noticed this similar issue.

Problem description:

Phone=iphone5, purchased brand new Dec 2012, no mishandling since use.

First tests (let's call this series of tests Tests_A) of surf and talk: right after getting new iphone5, end of Dec 2012.

Tests_A result: surf and talk working ok, but did not use Speedtest.net app to get download/upload speed.

Antenna shows 4 bars, LTE.

Tests_A setup: LTE enabled. During voice call, phone switched to 4G, which is normal. Internet access via Safari browser, Map, and other apps give acceptable feedback timewise.

Tests_A LTE Speedtest results were not that spectacular, in terms of the advertized LTE speeds: getting around 12 to 16 Mbps downlink. Don't remember exact uplink speed, up it's around 3 ~ 5Mbps.

Tests_B done Aug. 25, 2013 and Aug. 26, 2013.

Same iphone5, phone has not been dropped, has not suffered any abuses.

Antenna shows 4 bars, LTE.

LTE enabled.

I noticed that recently, in the same household, my LTE download and upload speeds have dramatically gone up.

Now I would get from 25Mbps to 30Mbps downlink, 15 to 18Mbps uplink, in same houshold, same spot in the same room.

However, I have also noticed that when a voice call is in progress, the internet access speeds while the call is in progress has deteriorated to about 1/4 of what 4G packet speeds should be.

When a voice call is in progress, Speedtest.net and CoverageMap would report very low downlink speeds of less than 1Mbps and sometimes 0Mbps for uplink. And if I try to run Speedtest.net a 2nd time during the same voice call, the app would return test failed null (didn't even get past ping test).

Yes, LTE is "supposed" to fallback to 3G/4G during a voice call, and I've seen first hand that this feature worked as advertized back in 2012 when I first got the phone.

What I'm reporting here, like some of the other people here, that this feature still works but the data transmission speed is much slower than our expectations.

I have reported this condition using at&t's "Mark the spot" app yesterday.

My observations:

Antenna reception has changed.

Used to be, Dec 2012, early months of 2013,

If LTE is disabled, iphone field mode would show antenna readout of approx -76db for 4G.

If LTE is enabled, iphone field mode would display antenna readout of approx -82db for LTE.

This is also the time period when Speedtest.net gives not-that-great LTE

download speeds of approx 12Mbps,

upload speeds of approx 5Mbps.

Recently, starting this Summer 2013, I noticed that antenna reception has changed.

If LTE is disabled, iphone field mode show antenna readout of approx -92 db for 4G.

If LTE is enabled, iphone field mode show antenna readout of approx -92 db for LTE.

Hmm... 4G and LTE antenna readout now identical everytime I enable or disable LTE.

(I have power cycled the iphone, reset network settings too)

And now, Speedtest.net shows improved downlink and uplink speeds when LTE is enabled.

So, all is good, and I'm a happy at&t customer.

But yesterday I thought of trying out the talk and surf feature again and found out that while LTE speeds have improved, the fallback to 3G/4G packet transmission speeds have deteriorated dramatically too.

I also tested this with my wife's iphone5, purchased brand new in Oct. 2013, same usag history (gentle handling, no drops or knocks on the iphone).

Same results of extreme packet slowness during voice call.

If LTE is disabled, Speedtest.net is run by itself (4G), not at the same time as a voice call:

downlink = 4.87Mbps

uplink = 0.83Mbps

(ran test just now, LTE disabled, 4G showing, -93db for antenna readout)

If Speedtest.net is run during a voice call (LTE disabled, show 4G):

downlink ==> 608.4 kbps

uplink ====> 104.4 kbps 

I have also swapped several phone cases and gotten similar results of dramatic packet slowdown during voice call.

During my evening walk I tested again when I was outside the house, approx 1 mile away, and got the same slowdown during voice call.

If you ask me, I think the LTE base station serving my household got upgraded and at the same time at&t removed the hsdpa/hsdpa+ base station to be used elsewhere. Why? It is overkill to have hpda equipment located in an area served by LTE base stations.

This may explain the reduction in 3G/4G antenna reception, going from -76db in Dec 2012 to -92db Summer 2013. While the number of bars may be the same, ie 4 bars, the decibel readout shows a reduction in reception.

I'm perfectly ok with this, referring to at&t moving equipment around. They gave me much faster LTE at the same time removing the older equipment.

I'm also ok with the current standalone 4G Speedtest results (standalone meaning no simultaneous voice call going on at time of speed test). What I don't get is why the cliff like drop in packet transmission rates during a voice call?

The speeds I've been getting during a voice call is almost like EDGE, even though the iphone still displays 4G.

Granted, talking and surfing simultaneously doesn't take place very often, but this feature is the ONE reason that I picked at&t over the others. Now I'll have to keep quiet in front of my friends to whom I've bragged about at&t's "Talk and Surf".

This "Talk and Surf" feature still works now, but it's much slower than our expectations of going from LTE to hsdpa+ speeds. We're seeing LTE going down to EDGE speeds.

I also understand that for some posters, they don't see this slow down. You'll have to run speedtest to see the slow down. When you're using apps during a voice call, the network speed is not consistent. It's more of like "come on, come on, come on!" when you're trying to display a restaurant's location on Maps when you're on a call with a friend, trying to set up a lunch get together.

Maybe we'll have to reply "I'll call you back later while I look up the restaurant." instead of what Steve Jobs showed during the first iphone demo.

Sorry, my mistake. Steve Jobs wasn't looking up the restaurant while he was on a call.

I reviewed the 2007 Apple Keynote again yesterday and saw that Steve sent an email with an attached photo during his call.

So is this limited to the iphone only?

Yes, for now only iphone5. You can search on the web to see if the newly released iphone5s allows simultaneous voice and data for CDMA based carriers (Verizon,Sprint). I'm not 100% sure, but I do remember reading web articles about how the new iphone5s also does not do talk and surf for Verizon/Sprint. Should be same for iphone5c.

Other phones, such as Samsung Galaxy S3 or S4 may be able to do simultaneous talk and LTE <--- note LTE speed, not fall back to slower 3G data because these phones have extra antenna(s). But we must not assume just because a phone is Android it can do this. You will need to research the phone's specs or ask the sales person a direct question.

But I have noticed that the carriers don't seem to be advertizing this talk and surf feature.

Just my thinking: evey user is a paid customer, and the carriers have a commitment to provide for accessibility. So if one user is in a voice call, he is already allocated the radio access bearer for 1 call. Now if he starts a data call, there needs to be extra resources, perhaps the air bandwidth (not 100%, just thinking out loud), resources on the base station, to handle this extra data call in addition to the existing voice call.

So now if the carrier gives 1 whole extra full capacity bandwidth for data to a user doing data calls at the same time this user already has an allocated channel for voice, won't the carrier run out of resources more quickly if everybody does talk and surf at the same time?

---

@bluemustang wrote:

Yes, for now only iphone5. You can search on the web to see if the newly released iphone5s allows simultaneous voice and data for CDMA based carriers (Verizon,Sprint). I'm not 100% sure, but I do remember reading web articles about how the new iphone5s also does not do talk and surf for Verizon/Sprint. Should be same for iphone5c.

 

Other phones, such as Samsung Galaxy S3 or S4 may be able to do simultaneous talk and LTE <--- note LTE speed, not fall back to slower 3G data because these phones have extra antenna(s). But we must not assume just because a phone is Android it can do this. You will need to research the phone's specs or ask the sales person a direct question.

 

But I have noticed that the carriers don't seem to be advertizing this talk and surf feature.

 

Just my thinking: evey user is a paid customer, and the carriers have a commitment to provide for accessibility. So if one user is in a voice call, he is already allocated the radio access bearer for 1 call. Now if he starts a data call, there needs to be extra resources, perhaps the air bandwidth (not 100%, just thinking out loud), resources on the base station, to handle this extra data call in addition to the existing voice call.

 

So now if the carrier gives 1 whole extra full capacity bandwidth for data to a user doing data calls at the same time this user already has an allocated channel for voice, won't the carrier run out of resources more quickly if everybody does talk and surf at the same time?

 

 

---

research the term VoLTE

Yes, VoLTE will be launched some time later this year.

http://www.dslreports.com/shownews/ATT-Plans-to-Offer-VoLTE-This-Year-125018

We shall see how talk and surf perform under VoLTE in real life for us at our locations of use.

---

@bluemustang wrote:

Yes, VoLTE will be launched some time later this year.

http://www.dslreports.com/shownews/ATT-Plans-to-Offer-VoLTE-This-Year-125018

 

We shall see how talk and surf perform under VoLTE in real life for us at our locations of use.

---

launch maybe, 100 percent rollout, at least 5 or more years