Can this account for shockingly unreliable browsing?
I can pull down maybe a page or two and then it seems to only connect and get data very occasionally, while my 770 can be merrily browsing the same sites using the same WLAN at the same time.
Can this account for shockingly unreliable browsing?
I can pull down maybe a page or two and then it seems to only connect and get data very occasionally, while my 770 can be merrily browsing the same sites using the same WLAN at the same time.
Your access point may not play nice with power saving mode (PSM) - you can reduce or disable the level of power saving in Connections->Advanced. PSM was added in later versions of OS2007 and caused problems for some routers (the minority fortunately) - OS2008 adds a GUI option to disable/reduce PSM if it isn't compatible with the users wireless router.
Can this account for shockingly unreliable browsing?
If you have buggy or misconfigured wlan router than yes. Powes saving mode support should be nowadays pretty normal thing but still some APs don't support it correctly or have it misconfigured by default. For misconfiguration look for parameters "Beacon interval" and "DTIM interval". Don't set it too high, something like 100 1 or 100 2 or 200 1 should be fine.
AFAIK devices in power saving mode wake up once per (DTIM*beacon interval) to check for new packets. On my AP I have beacon interval 100(ms) and DTIM set to 2 so the tablet periodically wake up each 200ms to get packets waiting for it in AP's buffer. So if the device is not sleeping when someone is sending packet to it, it will get the packet directly off the net and react immediately (like seen in those ping tests with power saving off or not effective). If not, access point will buffer it for the device and wake it as configured and resend all waiting packets in one go.
As for those ping tests - well this is pretty artificial test. If you really have such traffic (1 packet per second) and still require minimal latency then disable power saving or set sleep timeout interval above one second. And if traffic is continuous like this your device will not turn wi-fi chip off at all and will die in hour or so (but with low latency :-).
The worse latency seen in test proves that the tablet managed to sleep between those 1 second packets (and waked up in next beacon*DTIM period) which is a good thing for battery. This is actually a feature, not bug. It allows you listen to internet radio, browse web etc. while the wi-fi chip still manages to sleep most of the time.
If you want additional details, google for "wlan PSM" "wlan powersaving mode" or search also this forum or maemo lists for PSM timeout, or PSM interval.
Your access point may not play nice with power saving mode (PSM) - you can reduce or disable the level of power saving in Connections->Advanced. PSM was added in later versions of OS2007 and caused problems for some routers (the minority fortunately) - OS2008 adds a GUI option to disable/reduce PSM if it isn't compatible with the users wireless router.
Where is this GUI option in 2008? I haven't been able to find it anywhere. I have noticed that several other configuration options from 2007 are now missing as well. While my WAP supports PSM just fine, I am kinda curious about what effect the higher latency is having on overall bandwidth and if that in turn is having negative effects on media streaming, (ORB) in particular.
I am kinda curious about what effect the higher latency is having on overall bandwidth and if that in turn is having negative effects on media streaming, (ORB) in particular.
Theoretically wlan chip should never go to sleep if you are pumping a lot of data through it and trying to get maximum bandwidth. Anyway, overall wlan bandwidth is not very good. IMHO it is mostly caused by inefficient code in wlan driver which causes it to eat all the cpu resources on heavy wlan transfers. That's especially bad for media streaming, as video player has less cpu resources left on decoding. The higher is video bitrate, the more cycles get eaten by wlan driver thus starving the decoder. This looks like a purely software problem and hopefully it can be fixed later.
Some tests show that Nokia 770 wlan chip can transfer up to 2MB/s over McBSP bus, but I'm not sure if it can sustain such rate over a long period of time or can just do occasional burst transfers. A lot of things still need to be investigated and we don't have a complete picture yet.
PS. Please don't treat this post as a source of reliable information. It just reflects my current (definitely incomplete) vision of the problem and may be wrong.
Where is this GUI option in 2008? I haven't been able to find it anywhere. I have noticed that several other configuration options from 2007 are now missing as well. While my WAP supports PSM just fine, I am kinda curious about what effect the higher latency is having on overall bandwidth and if that in turn is having negative effects on media streaming, (ORB) in particular.
control panel --> connectivity -->connections --> (select connection) --> next, next, advanced --> other tab
Theoretically wlan chip should never go to sleep if you are pumping a lot of data through it and trying to get maximum bandwidth. Anyway, overall wlan bandwidth is not very good. IMHO it is mostly caused by inefficient code in wlan driver which causes it to eat all the cpu resources on heavy wlan transfers. That's especially bad for media streaming, as video player has less cpu resources left on decoding. The higher is video bitrate, the more cycles get eaten by wlan driver thus starving the decoder. This looks like a purely software problem and hopefully it can be fixed later.
Remember how Flash would (and still does) stutter while a Flash video is downloading, yet it plays fine once the download is complete? I wonder if this is due to the download over WiFi unecessarily sapping CPU cycles - I realise that some CPU cycles will be needed to download the Flash data, but I was surprised to see that enough cycles were taken to screw up Flash playback.
As a test I just disabled PSM on my N800/OS2008 (Linksys WRT54GS access point Beacon/DTIM set to 100ms/1ms respectively) and it seems (it's hard to quantify this scientifically) that browsing is faster with PSM disabled - pages seemed to download their resources much more quickly, the progress bar displaying "139/142" (or whatever) seemed to churn through each resource with much less delay. Anyone able to confirm this? My battery just died on me!
Any improvements to WiFi performance would be greatly appreciated - I feel that there is some "fat" in the WiFi stack which could be trimmed to the benefit of us all.
But the wi-fi driver is closed-source, propriaretary code.. therefore it must be good, no?
My opinion is that it's either too badly written that they're ashamed of showing it, or the device is so crappy that they're ashamed of showing it. However usually it's both
