Weird finding with E4200 - speed with mobile devices

[Plef5204]

I've run across a really weird issue with my Linksys E4200.

Ordinarily, this thing is a rock star.....with my current setup, it's moving files at up to 10 Mbps between computers in my house.....it'll move a gig of files in about a minute.

I'm *very* happy with that performance.

However, I've found something weird......I've noticed that when I connect my iPhone 4 or my ASUS Transformer TF101 to it (both wireless N devices), I get extremely slow file transfer speeds.....maybe 1 Mbps. And it fluctuates significantly. Sometimes it goes as high as 2 Mbps.

This is whether I'm moving files off my computer, or simply trying to stream from the web. It results in stuttering video when trying to watch Netflix etc. and that doesn't happen on the PC itself (which is connected wirelessly).

It also causes trouble with Skype.

I thought maybe the problem was the devices, but I have now tested them at work with our WNDR3700, and they connect at over 5 Mbps.

So it's something between them and the E4200.....any ideas?

Plef5204

 

[overdrive31]

All tablets and smartphones have only single stream wireless N. If you are using 40MHz channel bonding on the 2.4GHz, you should drop back to 20MHz. The speeds you're happy with without hiccups, could they be on the 5GHz band perhaps? Are there any wireless G devices on the network? When transferring data wireless to wireless the bandwidth gets split in half, add the factor of just single stream N, then if using 40MHz which can cause more problems than anything in 2.4GHz, I wouldn't be surprised as to the results.

 

[Plef5204]

I tried setting my 2.4 band to 20 instead of 40, and the speed of my iPhone and Transformer doubled. So, looks like that was the ticket.

Now, both of our Windows laptops only connect to 2.4 N, rather than the 5 GHz band.....previously, I could move files from a laptop in place spot of the house to the desktop PC (that connects to the 5GHz band), very quickly.....as I'd mentioned about 10 Mbps.

Does this change now mean the laptops won't connect as quickly for streaming of files?

The desktop serves as the main media PC. All our photos, music etc. are hosted on that desktop. So have I improved the performance of our tablet and iPhones, at the expense of our laptops? Or will that not be an issue?

And, btw, thank you for the suggestions.

Plef5204

 

[overdrive31]

Just leave 2.4GHz @ 20MHz and everything will perform just fine, 40MHz crowds the spectrum by 2/3 and causes too many problems. The laptops with MIMO(2 or more antennas) should get almost double the speed of the tablets and smartphones. The increased speed results you got from the tablets and smartphones should hold true for the laptops as well, and if not you can move them to the 5GHz which is 40MHz friendly.

 

[Dr Strangelove]

Oke pokey... I've just checked this out of interest myself, as I have a Linksys E4200v1 and use WiFi with estrong file explorer (Android) to my 802.11g XPERIA X10i from/to my QNAP NAS (gigabit LAN).

And if anything should be rotted, it should be my mobile phone.

I just tethered my XPERIA X10i using USB to my Notebook with a Wifi connection from the XPERIA X10i to the E4200.

My 2.4GHz WiFi interface is 40Mhz (2 channels) wide.

You won't catch me putting it back to 20Mhz

Mind you this means nothing to my 802.11g (54Mbps) mobile phone as it'll max any transfer at around ~24Mbps (theoretical) on a good day

I tried to be tricky by using the command prompt ftp, but it timed out all the time. It could log in and navigate folders but failed on any ls or get commands. Probably an IP port issue

So, plan B. I just did a Windows 7 drag and drop from my NAS to my Notebook via my mobile phone.

I was getting a transfer rate of ~1.73MB/s. That's approx 13Mbits/sec.

I'm sitting right under the E4200v1 so the transfer rate is as good as it'll get for me.

On my XPERIA X10i I do stream videos. In fact I'm watching the Avatar DVD (*.vob) from my NAS to my phone via the E4200v1 now. Using MX Video Player. BSPlayer is another good Video player for Android.

It's streaming at around 6Mbits/sec. Not the best picture (X10i uses an Adreno 200 GPU with a 1GHz CPU) and I'm guessing it's around ~20-25fps, BUT I am streaming a 720p DVD via the E4200v1 to my X10i and it is visually watchable with the frames being sync on the audio track.

This degrades noticeable if I'm more than 5metres+ from the router and walls/distance come into play.

I am using Tomato firmware on my Linksys E4200v1.. did I forget to say that eariler...

These are just my observations and don't attempt to provide a solution.


Update:

Just some additional stats for reference:

Using a Sony Ericsson XPERIA X10i 802.11g Android 2.3.3. FTP using AndFTP

QNAP TS-112 'baby' NAS

Using Linksys E4200 (Tomato fw) 40Mhz 2.4GHz and 100mW Power.

FTP download from NAS is as follows:

5m [1 wall] ~10.3Mbps
15m[3-4walls] ~4-5Mbps ~-70-75dBm

FTP with Linksys RE1000 range extender inserted with mobile phone indicating 12Mbps connection speed:

15m[3-4walls] ~6Mbps ~-50-55dBm

Watching a 720p DVD (*.vob) streamed from NAS at 15m[3-4walls] on XPERIA X10i gave considerable breakup, artifacts and 'missed' frames using Android MX Video Player.
Only a slight improvement with RE1000 where some of the 'stalls' and breakup is eliminated. To describe it, it'd be like watching a 'moving/visual' VERY high quality comic book picture. X10i is a VERY old Android phone with a VERY weak GPU (Adreno 200)

Devices (Alienware notebook) with strong(ish) WiFi transmitter operate faster without the Linksys RE1000 range extender in place. RE1000 is ONLY used to give my 802.11g phone more bars at the other end of the house. Unplugged when not needed.

Modern Android phones with 802.11n should give better throughput.

Notebook FTP transfers using 802.11n.

15m[3-4walls] ~64-80Mbps transfer using 40Mhz(802.11n) -60dBm
1m ~110-130Mbps transfer using 40Mhz(802.11n) -32dBm

Streaming the same 720p DVD on a Alienware M11XR1 using only the Intel built in GPU at 15m[3-4walls] 802.11n ~60dBm gives perfect playback with 5.1 surround sound.

I could be wrong but one only needs approx 12Mbps to stream a 720p DVD. Maybe up to 24Mbps for Full-HD and multiple audio channels. These number come down with compressed formats.

Thank you sfx2000 for valid point re: 802.11n 20MHz and mobiles [see below]

 

[sfx2000]

Keep in mind that most handhelds - iPhone 4, my HTC Thunderbolt 4G, etc...

While they are 802.11n, they're single stream, and... they only support 20MHz channels.

More importantly, I know that the iPhone will actively set the 40MHz Intolerant bit in the 802.11 framing, so many 11n 2.0 AP's will automatically reduce the channel to 20MHz.

You might get higher Wifi connection rates, but rarely does that translate into improved performance at the network layer.

 

[overdrive31]

Keep in mind that most handhelds - iPhone 4, my HTC Thunderbolt 4G, etc...

While they are 802.11n, they're single stream, and... they only support 20MHz channels.

More importantly, I know that the iPhone will actively set the 40MHz Intolerant bit in the 802.11 framing, so many 11n 2.0 AP's will automatically reduce the channel to 20MHz.

You might get higher Wifi connection rates, but rarely does that translate into improved performance at the network layer.

If it were all {automatic}, he would never had gotten positive results after manually changing to 20MHz only, as per instructed. The general rule, even recommended by most all manufacturers, is to only use 2.4GHz @ 20MHz setting on a router/ap. Oh, and not all handhelds use just 20MHz, many support 40MHz just in the 5GHz band. Think about it, why would manufacturers impose a limit to just 20MHz on the 2.4GHz band in their handheld products to begin with, then also recommend usage of only 20MHz on the 2.4GHz band of a router/ap.

 

[sfx2000]

Oh, and not all handhelds use just 20MHz, many support 40MHz just in the 5GHz band. Think about it, why would manufacturers impose a limit to just 20MHz on the 2.4GHz band in their handheld products to begin with, then also recommend usage of only 20MHz on the 2.4GHz band of a router/ap.

power - most critical path on the handheld front - 40MHz PA's pull more power for a given level of Rx/Tx... in the future, consider more streams, not more bandwidth...

NIC to CPU bandwidth - some use DMA, many use SDIO - no need for more that 20MHz of bandwidth, the skinny pipe there is the SDIO interface to the CPU and memory...

OEM's use SDIO vs. DMA due to much less demands on CCA layers and lines to route, and SDIO is good enough to ship...

 

[overdrive31]

Yes power usage is one factor to consider especially in such an portable device, but I would have to argue that reliability is just as important to consider by a manufacturer. Thanks for the in-depth explanations however. It all boils down to theoretical feature aspects vs. the actual observed performance. Isn't it a little evident that 40MHz channel bonding just doesn't belong on the 2.4GHz radio, seeing more and more routers coming that are only 20MHz capable in 2.4GHz. It's about damn time! Should have been that way from the start.

Case in point using 2.4GHz:

Plef w/ 40MHz = pathetic results, Plef w/ 20MHz = positive results

Dr w/ 40MHz = pathetic results, Dr w/ 20MHz = refuses to participate/see the light