View Poll Results: Do you get static in your BT headset during calls if WiFi is on?

Voters
6. You may not vote on this poll
  • Yes

    4 66.67%
  • No

    2 33.33%
Results 1 to 10 of 10
  1.    #1  
    This is something that has been mentioned in the past in a couple of threads:
    Static when talking on phone

    Heavy static when using a Motorola H680 headset?

    But I figured it's time to capture this one in a poll.
  2. #2  
    I usually don't crosspost...but when I've already summed my thoughts up so nicely....


    Quote Originally Posted by Ebag333 View Post
    Radio interference can (and does) happen on any device.

    In fact, HP has a quite interesting PDF on this topic. They have a few excellent statements that sum up the problem quite well:


    Because both Wi-Fi™ and Bluetooth™ wireless technology share spectrum and will often be located in close physical proximity to one another, there is concern for how they may interfere with one another.

    ...

    Since Wi-Fi wireless local area networks (WLANs) and Bluetooth are complementary technologies, they will often be used in close proximity to one another. Neither Wi-Fi nor Bluetooth was originally designed with mechanisms in place to deal with the interference that each creates for the other.

    ...

    How Bluetooth and Wi-Fi Interfere

    Wi-Fi and Bluetooth both occupy a section of the 2.4 GHz ISM band that is 83 MHz-wide. Bluetooth uses Frequency Hopping Spread Spectrum (FHSS) and is allowed to hop between 79 different 1 MHz-wide channels in this band.

    Wi-Fi uses Direct Sequence Spread Spectrum (DSSS) instead of FHSS. Its carrier does not hop or change frequency and remains centered on one channel that is 22 MHz-wide. While there is room for 11 overlapping channels in this 83 MHz-wide band, there is only room for three non-overlapping channels. Thus there can be no more than three different Wi-Fi networks operating in close proximity to one another.

    When a Bluetooth radio and a Wi-Fi radio are operating in the same area, the single 22 MHz-wide Wi-Fi channel occupies the same frequency space as 22 of the 79 Bluetooth channels which are 1 MHz wide. When a Bluetooth transmission occurs on a frequency that lies within the frequency space occupied by a simultaneous Wi-Fi transmission, some level of interference can occur, depending on the strength of each signal.

    They then go on to discuss some of the various ways that each tries to deal with it, and some of the other factors. It's really quite a fascinating whitepaper.

    http://www.hp.com/rnd/library/pdf/Wi...oexistance.pdf


    It's not really a "bug" with the device, since it can (and does) occur between any bluetooth and wireless device (like in my case with a bluetooth mouse and my wireless access point).

    I actually noticed some problems with my wireless mouse when my access point was sitting within 3 feet of the mouse/receiver. Since I've moved my wireless to the other side of the house, not only does my mouse have a lot less problems, but the range was hugely increased (from less than 2 feet to over a dozen feet).
    And to sum up my already summed up thoughts:


    It's a moot point.
  3. #3  
    yeah, it actually makes the other person sound like a robot, then i just disable the wifi and it's normal again.
  4. #4  
    Me as well. I rarely use WiFi, but it definitely has static issues.
  5. #5  
    what Ebagg said makes sense. I don't get static but the caller breaks up, this does not happen all the time. I think due to what channel each is on as bt will change channels, some interfere and some don't.
    Still waiting for Hitachi to reintroduce the G1000 with a VGA screen and more memory. I still miss that crash prone beauty.
  6.    #6  
    Yes this is very much a known issue. Perhaps BT 3.0 (whatever comes in the future) can provide a resolution.

    The poll results are always interesting.
  7. #7  
    This is something I don't get. What Ebag posted makes sense, but it also doesnt (at least not anymore).

    All of the bluetooth profiles transmit their data and are subject to the same level of interference. They don't have issues though, because they represent the data digitally and have error detection and retransmit mechanisms in place. Why is the HS (headset) profile different than A2DP, HF, AVRCP, BPP, FTP, etc? Maybe when bluetooth was first spec'ed they were concerned about introducing latencies or something, but in this day and age, given the low requirements of HS, it just doesn't make sense.

    While you might still suffer from digital hiccups or drop-out if you aren't within range or are running into retransmit timeouts, there really is no good reason that headsets should be allowing static these days. As darnell said, perhaps 3.0 introduces a more advanced headset profile.
  8. #8  
    Quote Originally Posted by zbop View Post
    This is something I don't get. What Ebag posted makes sense, but it also doesnt (at least not anymore).

    All of the bluetooth profiles transmit their data and are subject to the same level of interference. They don't have issues though, because they represent the data digitally and have error detection and retransmit mechanisms in place. Why is the HS (headset) profile different than A2DP, HF, AVRCP, BPP, FTP, etc? Maybe when bluetooth was first spec'ed they were concerned about introducing latencies or something, but in this day and age, given the low requirements of HS, it just doesn't make sense.

    While you might still suffer from digital hiccups or drop-out if you aren't within range or are running into retransmit timeouts, there really is no good reason that headsets should be allowing static these days. As darnell said, perhaps 3.0 introduces a more advanced headset profile.
    Well, first all, it's not me saying it. I'm merely copying and pasting what people much smarter than me are saying.

    I figure if it's something they're doing for a living, there's a fair chance they know more about it than I do.

    Anyway, if you want a more in depth explanation here's a very detailed white paper on it.

    Long story short, what I'm gathering from it is that the impact is usually below 25%.

    http://www.eurescom.de/~pub-delivera...LTandWLAN.html

    (Yes the paper is geared towards the European market and references some European regulations, but the specs--and basic ideas/math--are essentially the same for the US market.)




    Here's another one that was linked from ZDNet:
    http://rfdesign.com/mag/410rfdf1.pdf

    This one talks more about the challenges of Bluetooth and Wifi in the same device, and how to resolve that.

    The interesting graphs are on page two though.

    With just Bluetooth on, and the receiving BT device 0 meters away from the phone/laptop/etc, throughput is roughly 550 kb/s. The instant you turn on Wifi the throughput drops to just over 300 kb/s.

    At a distance of 10 meters, with WiFi off Bluetooth throughput is still above 500 kb/s. With WiFi on, Bluetooth throughput is nearly zero.

    Again the white paper mentions an interference of about 25% of the time.



    Anyway, long story short, WiFi can have a huge impact on Bluetooth. While most of us aren't using our headsets 10m away from our phone, 1-2m isn't uncommon and really even up to 3-5m is going to happen. From the graph in the second white paper, that puts our throughput somewhere around 150-200 kb/s. Seems like a lot, but keep in mind that's down from over 500 kb/s.


    Now add in some other factors, like your body between the phone and the headset (headset in right ear, phone in left pocket). The human body is amazingly efficient at blocking radiation, and will have a very large negative impact on the throughput of bluetooth. That could bring your throughput down to 0, even if the distance is only a few meters.

    And of course as we all know, poor connection/signals can have all sorts of negative impacts, from dropping the calls/connections completely, to stuttering, to static, to shifts in vocal tone (that's always interesting ), etc etc etc.
  9. #9  
    Ebag, I think you completely missed my point...

    I'm not disagreeing with what you posted, merely making commentary on what's wrong with the current HS profile implementation.

    Does wifi interfere with bluetooth? (yes)
    Do certain bluetooth headsets have static as a result? (yes)
    Should the current HS profile be improved so that static doesn't occur? (yes)

    Static is an artifact of analog signals and reception, and exists in older technologies such as broadcast TV, FM radio, and early cell phone implementations; it has no place in a digital world. The other bluetooth profiles have already addressed signal interference, so there is no reason that a future HS profile shouldn't address it as well.
  10. #10  
    Quote Originally Posted by zbop View Post
    Ebag, I think you completely missed my point...
    Apparently.

    Oh well. It's still interesting reading!

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