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  1. #1
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    Network Based module and cell-based positioning confusion

    Once more your help is needed...

    This time it's about the Network Based module and cell-based positioning. I am a bit confused about the two.

    I wrote a test program that lists the available modules of my phone and also if the module is available, using RPositionServer::GetNumModules(), RPositionServer::GetModuleInfoByIndex() and TPositionModuleInfo::IsAvailable().

    When I run the program on my Nokia E51 2 modules are found: "Bluetooth GPS" and "Network Based" and both are unavailable. For the Bluetooth one I can understand it, I don't have a Bluetooth GPS but why is the Network Based module unavailable?

    What do I need to use cell-based positioning? I thought it could be used on all cell-phones as long as they support the LBS API.


    Please guide me into the light.

  2. #2
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    Re: Network Based module and cell-based positioning confusion

    Nope. The network-based LBS needs LBS support from the network operator.

    Without network operator support, all you can get is the cell ID of the cell/basestation you are currently connected to, and just having that is not very useful. You would have to separately obtain coordinates of where the basestation physically resides, and in order to know in which direction from the basestation you are - roughly - you would have to know how the basestation antenna is directed, and its sector width. And you'd need other data like timing info, signal strength, etc., for more accurate estimation. And for proper triangulation, you'd need to be able to ascertain also other nearby towers and have the same data from them, before you'll get very close to your true position.

    So, the only way for decent accuracy is that your network operator supports LBS, or that you have a real GPS receiver (built-in or an external Bluetooth receiver).

    Ask your network operator whether they support network based LBS at all. If not, ask if others in the area do. Don't try to build an application that depends on the availability of LBS support by network operators (most don't, so depending on it is fairly useless, but of course you can try to sell such an application to operators with such support; nobody else is likely to buy).

  3. #3
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    Re: Network Based module and cell-based positioning confusion

    I'm confused again...

    I contacted one of the operators here in Belgium, Proximus, and asked if their network supported cell-based positioning. They answered that it did: the normal, GPRS, supported it. But, I asked, what about the GSM network? Yes, the guy answered, the user doesn't have to enable anything, it will work.

    Maybe I didn't understand him correctly. It was difficult communicating because the guy was obviously native french-speaking and I am dutch-speaking. And although his Dutch was quite good, perhaps the technical stuff didn't come over correctly.

    So, is it possible to do positioning using plain GSM (if the network supports it), or do you need at least a 2G connection?

  4. #4
    Nokia Developer Moderator
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    Re: Network Based module and cell-based positioning confusion

    It is one thing for a positioning module to be installed, another thing for it to be available (enabled) and quite another think for it to be able to provide the service.

    If I understand you correctly you read the two positioning modules above as unavailable by calling the TPositionModuleInfo::IsAvailable(). Well, according to the API's documentation:

    Return values:

    ModuleId() returns a unique identifier that specifies the position module.

    IsAvailable() indicates if the positioning module is available for use. In general, a module is unavailable if it has been taken off-line by the user via the control panel, or if there is a hardware problem.

    TechnologyType() returns a bit mask of values indicating what are the primary technologies used to obtain position information. This can be a combination of terminal and/or network based mechanism. It also indicates if the primary mechanism has been assisted.
    So, to begin with, is the Network Based Positioning module enabled on your phone's settings? Until this is clarified any other discussion about operators and their support is futile.
    -- Lucian

    If you are not yet a DVLUP member it is time to correct that mistake :) Click here to join: http://www.dvlup.com/lucian/Invite

  5. #5
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    Re: Network Based module and cell-based positioning confusion

    ltomuta is right. You can enable network-based positioning from Tools | Settings | General | Positioning | Positioning methods. Enable "Network based" option there.
    Antony Pranata
    http://www.antonypranata.com/
    http://www.s60tips.com/

  6. #6
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    Re: Network Based module and cell-based positioning confusion

    I checked the settings and "Network Based" was already checked.

    Tools | Settings | General | Positioning | Positioning server | Access point was set to 'none'; I had following choices: none (checked), Mobistar Internet, Mobistar MMS, Mobistar Pro-internet, Orange World, TV Video.
    Tools | Settings | General | Positioning | Positioning server | Server address was set to h-slp.mnc010.mcc206.pub.3gppnetwork.org

    I checked Mobistar Internet and Mobistar MMS and ran my test app again. Result: still no change. And now I don't have the option to put the access point to 'none' any more.

    Do I need a server, and thus an internet connection, to use network based positioning?

    So what are the requirements (network, phone, etc) for cell-based positioning?

  7. #7
    Nokia Developer Moderator
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    Re: Network Based module and cell-based positioning confusion

    Of course you need a server and a valid access point.

    Where have you got that slp.mnc010.mcc206.pub.3gppnetwork.org from?
    -- Lucian

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  8. #8
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    Re: Network Based module and cell-based positioning confusion

    Quote Originally Posted by ltomuta View Post
    Where have you got that slp.mnc010.mcc206.pub.3gppnetwork.org from?
    It was set like this by default, I haven't touched it.

    Quote Originally Posted by ltomuta View Post
    Of course you need a server and a valid access point.
    Ah, ok, I think I'm starting to get it.

    I thought network based positioning used only the GSM infrastructure. That it got its information just from cell towers. But instead, you need an internet connection to get a location.

    Am I correct?

    I haven't found a site or document explaining in detail how it works. Maybe you know?

  9. #9
    Nokia Developer Moderator
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    Re: Network Based module and cell-based positioning confusion

    The phone can get some positioning info, like a cell id, but how do you map that to a useful position estimate? Some network based server would have to accept your request, convert the info you have into location and then send the location info back to you.

    A search for "pub.3gppnetwork.org" retrieves some interesting discussions regarding the plans for those mnc<MNC>.mcc<MCC>.pub.3gppnetwork.org subdomains but I could not find a statement about the existence of a service behind the URL(s).
    Last edited by ltomuta; 2008-09-12 at 17:15.
    -- Lucian

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  10. #10
    Nokia Developer Expert
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    Re: Network Based module and cell-based positioning confusion

    Quote Originally Posted by NickDeGraeve View Post
    I checked the settings and "Network Based" was already checked.

    Tools | Settings | General | Positioning | Positioning server | Access point was set to 'none'; I had following choices: none (checked), Mobistar Internet, Mobistar MMS, Mobistar Pro-internet, Orange World, TV Video.
    Tools | Settings | General | Positioning | Positioning server | Server address was set to h-slp.mnc010.mcc206.pub.3gppnetwork.org

    I checked Mobistar Internet and Mobistar MMS and ran my test app again. Result: still no change. And now I don't have the option to put the access point to 'none' any more.

    Do I need a server, and thus an internet connection, to use network based positioning?

    So what are the requirements (network, phone, etc) for cell-based positioning?
    The address you have is an auto-generated address as specified by OMA. If the device does not have server address, it have to auto-generate one, using MNC and MCC for the device.

    Change the server settings to : supl.nokia.com

    and it should work. This is the address of Nokias own SUPL Server, which does support network based positioning.

    Br, Jesper Sandberg.

  11. #11
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    Re: Network Based module and cell-based positioning confusion

    My apologies for not getting back earlier.

    I've done some investigating and this is how I understand things now:

    The Network Based module needs 2 thing to work: 1. an operator that supports it; 2. a connection to a server.

    These conditions make using this method of positioning not an option. Few operators support it and and I don't want my application to use any external servers or connections.

    The alternative is to develop my own system of positioning. To achieve a workable level of accuracy any method needs the signal strength of not only the currently connected tower but of all visible ones.

    From what I understand only the info of the current tower is available with Symbian SDK, via the ETEL3RDPARTY API. (link) If I need also the info of the other towers I will need an SDK from the cell phone manufacturer I'm targeting. For example Nokia provides such an SDK if you pay a fee and become a partner. (link)


    Is my analysis correct? Do you have anything to add?

  12. #12
    Nokia Developer Moderator
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    Re: Network Based module and cell-based positioning confusion

    Have you tried Jesper's suggestion from the post above?
    -- Lucian

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