Mystery 3G data usage: A-GPS? WIFI!?

theCzar

I have a Nokia N85 and an O2 contract (active life 40). I was recently perusing my bills (my usage is usually light and I don't often delve into the details) and I've found that I have many very small data transmissions, less than 10kb at a time.

Since I rarely use anything but the phone's wifi for connecting to the internet, I'm at a loss as to what is accounting for these data packets.

Here in Ireland, the cost is negligible but I travel a lot and the costs can add up, see below, cost at the end, over 3 euros for 19kb:

Roaming Data Usage 14/04/09 Data Roaming 10.0 KB 2.48
Roaming Data Usage 16/04/09 Data Roaming 9.0 KB 0.66

The only thing I can imagine is happening is that when I use the A-GPS and it pings the local tower to get an approx position, am I then paying to ship that ping packet all the way to the land of my fecking fathers? Is Opera mini or Nokia's internet app doing some fiddling on the side while I establish a wifi link?

PS I am prompted when opening Nokia maps to go online yay/nay and I always click nay, having preloaded the maps.

EDIT: with some research (which in hindsight i should have done first), I have found AGPS does indeed cost money, which is probably what my charges are caused by. If a Mod wants to delete this thread, feel free. Or leave it for future noobs to not search for before posting the same question in a new thread (Albeit less eloquently)

Random

We'll leave the thread. The next person who searches will find it

mobius42

theCzar wrote: »

EDIT: with some research (which in hindsight i should have done first), I have found AGPS does indeed cost money, which is probably what my charges are caused by.

That's it alright. A-GPS is assisted GPS. It offloads some of the GPS calculations to an online server to reduce the time it takes to get a lock. It's odd that the Nokia maps calculation still accesses this despite you telling it not to.

towel401

mobius42 wrote: »

That's it alright. A-GPS is assisted GPS. It offloads some of the GPS calculations to an online server to reduce the time it takes to get a lock. It's odd that the Nokia maps calculation still accesses this despite you telling it not to.

A-GPS is an ingenious way of getting people to pay for a free service its a shame so many phones have A-GPS instead of a proper GPS

Rsaeire

towel401 wrote: »

A-GPS is an ingenious way of getting people to pay for a free service its a shame so many phones have A-GPS instead of a proper GPS

I agree with your comment regarding pricing. It defeats the purpose of using GPS, when the A-GPS feature is used instead, as most people would not be aware of the charges associated with it and therefore be turned away from GPS/A-GPS entirely.

On the flip side you have people using GPS, waiting for a lock and getting tired when it takes over a minute. As a result of this, I can fully understand why the manufacturers have been putting A-GPS in their handsets and pushing the feature. I guess the moral of this story is, people are impatient.

Davy

And if you have a data plan for the net anyway it doesn't even effect you. Over time im sure most people will have some sort of data package.

towel401

Rsaeire wrote: »

I agree with your comment regarding pricing. It defeats the purpose of using GPS, when the A-GPS feature is used instead, as most people would not be aware of the charges associated with it and therefore be turned away from GPS/A-GPS entirely.

On the flip side you have people using GPS, waiting for a lock and getting tired when it takes over a minute. As a result of this, I can fully understand why the manufacturers have been putting A-GPS in their handsets and pushing the feature. I guess the moral of this story is, people are impatient.

very much so. even ordinary GPS works fairly well in the cities but a cold start takes a few minutes. if the software controlling the GPS on the phone was written a bit better there would be no need for AGPS. Too bad D-GPS and the likes never caught on - a phone with D-GPS would be nice

Davy wrote: »

And if you have a data plan for the net anyway it doesn't even effect you. Over time im sure most people will have some sort of data package.

that is just about the worst reason ever to get a data plan

Davy

Davy wrote: »

that is just about the worst reason ever to get a data plan

Thats not what i said:

if you have a data plan for the net anyway it doesn't even effect you.

towel401

Davy wrote: »

Thats not what i said:

until you go abroad like the OP did and you're not on 3 like home or something similar. the idea behind the system is ridiculous and the phone networks are making a killing out of something that used to be free.

mobius42

towel401 wrote: »

until you go abroad like the OP did and you're not on 3 like home or something similar. the idea behind the system is ridiculous and the phone networks are making a killing out of something that used to be free.

That's not strictly true. They don't charge you for using A-GPS, it just requires a data connection. It was invented with the intention of reducing the time to get a GPS lock, not as some money making scheme. The GPS chip will work without a data connection, just more slowly. However, on most phones, the maps are not stored locally, so without a data connection you can't use it. Domestic data has drastically reduced in price in recent years, so it's not a big issue there.

The real issue here is the crazy cost of data when roaming. Hopefully, the EU will do something about roaming data like they did with calls and texts. For example, O2 have a roaming data offer of 50MB, but it costs €50!:eek:

Sam Vimes

mobius42 wrote: »

That's it alright. A-GPS is assisted GPS. It offloads some of the GPS calculations to an online server to reduce the time it takes to get a lock. It's odd that the Nokia maps calculation still accesses this despite you telling it not to.

I don't think that's how it works. No online server does calculations for the phone, what happens is the phone gets a rough idea of its location based on the coordinates of the nearest cell towers which makes getting a lock faster

mobius42 wrote: »

That's not strictly true. They don't charge you for using A-GPS, it just requires a data connection.

I don't think that's true either

If it uses the data connection then the operators of course charge for it

mobius42 wrote: »

However, on most phones, the maps are not stored locally, so without a data connection you can't use it.

They're not stored by default but with most if not all phones you can pre-load maps by downloading them to your computer and transferring them to the phone so a data connection is not absolutely necessary as long as you're prepared

mobius42

Sam Vimes wrote: »

I don't think that's how it works. No online server does calculations for the phone, what happens is the phone gets a rough idea of its location based on the coordinates of the nearest cell towers which makes getting a lock faster

It does use cell towers, but it also offloads calculations and does other things using an assistance server: http://en.wikipedia.org/wiki/AGPS

Sam Vimes wrote: »

I don't think that's true either

If it uses the data connection then the operators of course charge for it

I meant that you are not charged to access the assistance server by whoever runs it, not that operators don't charge for the data it uses.

Sam Vimes

mobius42 wrote: »

It does use cell towers, but it also offloads calculations and does other things using an assistance server: http://en.wikipedia.org/wiki/AGPS

That's the same page I read but I really should have read the whole thing

It seems we're both right:

That assistance generally falls into two categories: a) information used to more quickly acquire satellites, or b) calculations done remotely:

mobius42 wrote: »

I meant that you are not charged to access the assistance server by whoever runs it, not that operators don't charge for the data it uses.

Ah it all makes sense now

kirving

I have an N85 as well and have it set to confirm all internet connections. Occasionally, after the phone being left down or in my pocket, I'll notice a confirmation message asking to I want to connect to "Meteor Data".

I just press no when it happens, but when I press yes, no application is launched or anything like that. This is with A-GPS tracking off by the way.

I have no idea why it happens. Shoddy firmware on the n85 probably...

glornadtonn

Well I'm glad this thread wasn't deleted!!

Just wondering if anyone knows what kind of data useage does using A-GPS incur for say a 1 hour trip (in Ireland)? i.e. how often does the phone fix it's position at 10kb a fix? (I'm assuming from the original post that it uses 10kb to fix its position)