Samsung's problem with CDMA


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  1. infamousjax

    infamousjax Well-Known Member This Topic's Starter

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    I'm not sure what their problem is, but it seems like Samsung certainly has a big problem with their Android phones on CDMA networks.

    The pattern seems to run with the radio having problems. It started with the Moment where the phone's radio would constantly have dropped connections and lock-ups, and the phone going into Airplane mode randomly.

    The Intercept has it's fair share of radio issues as well, however, I can't list the exact problems as I've never owned one.

    Now, with the Epic, I'm afraid that this pattern continues.

    After a lot of research, tinkering, and just general speculation, I think that what's happened is that Samsung has "jimmy-rigged" GSM radios to work with CDMA networks. This would explain the problems that are seen in the Moment, Intercept, and now the Epic 4G's data upload cap, and maybe even the time without a signal problem as the phone could be searching for GSM networks. It even show's that the Epic's preferred network in the advanced settings is WCDMA -- which IS a GSM network.

    Don't get me wrong, i love my Epic 4G, but I have a lot of problems with the damn radio. Calls are great no matter what the signal bars show, but the problem comes with the 3G data. My phone will be at full signal in my house, and then suddenly drop down to no signal for no apparent reason. Sometimes when I run a speed test, I get speeds as slow as 30-50kbps/sec download which is absolutely horrendous.

    The good news is this appears to be a software problem and can be fixed if Samsung wants. Let's hope they do, as being a previous Moment owner this kind of issue is very disheartening.

    Before you think about flaming -- Please realize that this just speculation, and was hoping for some your input and/or experiences with the same issues that I'm having.
     

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  2. RickJ

    RickJ Well-Known Member

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    This might be of interest Difference Between WCDMA and GSM | Difference Between | WCDMA vs GSM

     
  3. gtl408

    gtl408 Well-Known Member

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    Thanks for bringing this up. That was one thing I did notice between the Epic and its brothers on the AT&T and T-Mobile networks. While the Captivate/Vibrant signal indicators would jump around, I never found the actual data speeds to fluctuate as much as it does with the Epic. Now that the Fascinate has finally been released, I posted the following to see what Fascinate owners are getting with their speed tests: http://androidforums.com/samsung-fascinate/172795-whats-your-3g-speed.html#post1556774

     
  4. jim2point0

    jim2point0 Well-Known Member

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    It's a huge problem. You can't do jack crap with 150 KB upload. I didn't think it would be an issue at first... but then I started to really test it out. The Epic has SO much potential. If they'd just fix the issues before my 30 days are up.... I'll keep it.
     
  5. Bitbang3r

    Bitbang3r Well-Known Member

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    I find it hard to believe Samsung has CDMA issues that are of its own making. I mean, for god's sake, this is a company whose home market is basically 100% CDMA and has been making phones for Sprint and Verizon since literally the last century. I'm not saying there aren't problems, but rather that if there are, they're at least as likely to be due to Android itself (which WAS designed first and foremost for GSM, and had CDMA grafted on almost as an afterthought, and mostly by trying to make it look like GSM to the rest of the OS). As far as the chips and hardware are concerned, I doubt there's another company on *earth* with more experience designing and building CDMA phones than Samsung.

    Case in point: suppose that whomever wrote the lower-level native library used by Android for socket connections designed its buffering and flushing algorithm around the way GSM networks work, then at some later point, someone hacked his or her original code to thunk CDMA into working with the same base library. Now... suppose that library flushes every 5,000 bytes, but EVDO has a frame size of 6,000 bytes. If that person were in a hurry, he might have designed it to just buffer 5,000 bytes and auto-flush, then buffer the next 1,000 bytes and flush when commanded. If whomever wrote the higher-level code (say, a Sprint employee) knew that 6,000 was the most efficient size for an EVDO chunk, he'd most likely design HIS code to deal with 6,000-byte chunks... but in reality, due to the thunking layer, it would be flushing and handshaking twice as often.

    Now, this is an entirely contrived example with made-up numbers, but it hopefully illustrates the point: if one layer of the phone's network stack was optimized (or hardwired) for GSM, and CDMA differs in some way that causes more frequent buffer-flushing or other protocol activity, that would definitely explain the worse performance. It wouldn't even have to be something blatant or major... maybe there's something that can be discerned instantly on a GSM network, but takes 200ms to read on a CDMA network. A naive higher-level driver that thunks to the GSM code would have its performance killed.

    Actually, if uploads literally max out at 153kbit, that almost sounds like someone at Sprint or Samsung cut and pasted a chunk of code written for 1xRTT, then hacked it a bit to work with EVDO before spending the other 99% of his development time optimizing it for 4G WiMax performance. Or possibly even INSERTED a chunk of code intended to simulate 1xRTT for some experiment, then forgot to remove/disable it until it was too late.
     
  6. gtl408

    gtl408 Well-Known Member

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  7. Stoney62

    Stoney62 Well-Known Member

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    Wondering how they figure customers should run WIMAX on 150kbps upload?
     
  8. Eazail70x7

    Eazail70x7 Well-Known Member

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    My uploads on 4g are always above 1mbps. If they weren't capping 4g upload speeds at 1mbps, it would be higher. I seen it shoot way past 1mbps but the cap brings it back down. This is the same as on the Evo and all of Sprints 4g devices.

    3g is a whole different story. It seems to have a upload speed capped at 150kbps

    http://androidforums.com/samsung-fascinate/173290-charging-time.html

    It looks like the Fascinate may have the tws issue also?? ^^^
     
  9. Droidasaurus X

    Droidasaurus X Member

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    It's not Android or else the Fascinate would have similar problems. I get what you're trying to say but that doesn't seem to be the case here. It looks most definitely like a Sprint or Samsung cap using software. More than likely Sprint since neither of the other three Galaxy S phones have this problem.
     
  10. jersey221

    jersey221 Well-Known Member

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    a gsm radio wouldnt work with cdma.
     
  11. Bmerz

    Bmerz Well-Known Member

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    Well, all I can say is; if it is Sprint putting a deliberate cap on us, then I know what they can do with that 4G extra $10 fee they are charging us! :mad: I knew I shouldn't have left Tmo, but I didn't like their phone line-up and loved everything spec wise on the Epic, so I decided to give Sprint a chance.

    Thankfully, I am on my 30-days - and if there's no fix before Sept 27th, then I guess it'll be hello again to Tmo. I don't want to go back to Tmo, but I cannot justify paying $50 more for a phone, and an extra $10 for (so-called 4G that I don't have) on a buggy phone, and Sprint's greed.

    So I hope that this issue is not Sprint's doing, or if it is - that it's not deliberate. I guess time will tell, although I don't have much time left... *sighs*
     

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