How to get a stable WLAN-connection with a Lenovo x121e?

Question

I have permament problem when using WLAN with my Lenovo ThinkPad x121e. The wireless network adapter in use is this one:

lspci:

01:00.0 Network controller: Realtek Semiconductor Co., Ltd. RTL8188CE 802.11b/g/n WiFi Adapter (rev 01)

The connection normally works OK for some time and then starts to slow down and eventually disconnects. Sometimes the connection is reestablished seconds later, sometimes it takes 30 or more seconds, sometimes it does not reconnect at all.

This problem occures with every driver I tried up to now. Especially the kernel driver

Linux ThinkPad 3.0.0-14-generic #23-Ubuntu SMP Mon Nov 21 20:28:43 UTC 2011 x86_64 x86_64 x86_64 GNU/Linux

and Realteks driver that can be found here. The driver I'm using at the moment is the one found in this ppa: ppa:tista/x120e.

Here is another link to www.thinkwiki.org that hints at a "Low Power State" (LPS) option in realtek's driver but it seems that it cannot be disabled in the current driver.

Is there a way to get a more stable WLAN with this setup?

Some more system information:

lshw -class network:

   description: Wireless interface
   product: RTL8188CE 802.11b/g/n WiFi Adapter
   vendor: Realtek Semiconductor Co., Ltd.
   physical id: 0
   bus info: pci@0000:01:00.0
   logical name: wlan0
   version: 01
   serial: 38:59:f9:db:e6:83
   width: 64 bits
   clock: 33MHz
   capabilities: pm msi pciexpress bus_master cap_list ethernet physical wireless
   configuration: broadcast=yes driver=rtl8192CE driverversion=0006.0321.2011 firmware=56 ip=192.168.178.35 latency=0 link=yes multicast=yes wireless=802.11bgn
   resources: irq:17 ioport:3000(size=256) memory:f0200000-f0203fff

iwconfig wlan0:

wlan0     802.11bgn  ESSID:"xxx"  Nickname:"rtl8192CE"
      Mode:Managed  Frequency=2.452 GHz  Access Point: A2:05:43:2F:6E:8E   
      Bit Rate=65 Mb/s   
      Retry:on   RTS thr:off   Fragment thr:off
      Power Management period:0us  mode:All packets received
      Link Quality=100/100  Signal level=0 dBm  Noise level=-120 dBm
      Rx invalid nwid:0  Rx invalid crypt:0  Rx invalid frag:0
      Tx excessive retries:0  Invalid misc:0   Missed beacon:0

ifconfig wlan:

wlan0     Link encap:Ethernet  HWaddr 38:59:f9:db:e6:83  
      inet addr:192.168.178.35  Bcast:192.168.178.255  Mask:255.255.255.0
      inet6 addr: fe80::3a59:f9ff:fedb:e683/64 Scope:Link
      UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
      RX packets:117385 errors:0 dropped:0 overruns:0 frame:0
      TX packets:85652 errors:0 dropped:0 overruns:0 carrier:0
      collisions:0 txqueuelen:1000 
      RX bytes:115417879 (115.4 MB)  TX bytes:10463799 (10.4 MB)
      Interrupt:17 Memory:ffffc900037a8000-ffffc900037a8100 

Solution 1

I finally fixed this problem by compiling and installing the latest drivers from Linux Wireless in Ubuntu 12.04, in my case the "compat-wireless-3.5.1-1-snpc.tar.bz2" package: http://wireless.kernel.org/en/users/Download/stable/

One needs the header files for his kernel and the build-essentials package. I recommend also to run the script "driver-select" with the option rtlwifi before compiling because one doesn't need the other drivers and it reduces building time:

sudo apt-get install linux-headers-$(uname -r) build-essential

tar jvxf compat-wireless-3.5.1-1-snpc.tar.bz2
cd compat-wireless-3.5.1-1-snpc
./scripts/driver-select rtlwifi
make
sudo make install

But the downside is you have to rebuild the driver after every kernel update.

I'm running the driver for two days now with excessive closing and opening the lid and didn't get any disconnects.

Solution 2

The problem could be caused by channel hopping (and the new Linux kernel).

I fixed it mostly with compile the driver by my own and install it. 2nd thing I did was to scan for networks if the network is breaking.

I entered in terminal watch sudo iwlist wlan0 scan.

With this the driver kept awake. Another fix I used is to press Fn+F5 to disable wifi and then I do the same a few seconds later.

One more thing I tried:

sudo modprobe -r rtl8192ce
sudo modprobe rtl8192ce

This reloads the driver for wifi. I also ping sometimes the router, this keeps my wifi connection stable.

Solution 3

I did the same: disabled the WLAN port in the BIOS, removed the Realtek card and added a Intel Centrino 6200 to the WWAN port. I used a MiniPCIe adapter half->full (costs less than 5Eur) to secure the card in place.

Solution 4

This link gave me the hint to try the option ips=0 for the module rtl8192ce to turn off all power saving with the wlan adapter. Up to now this gives me the best behaviour - no drop outs, no disconnects. This surely will have an efect on power consumption - we will see. I'm using the build in drivers with kernel 3.0.0-15 for now.

Solution 5

I ended up replacing the WLAN card as I was unable to get a stable connection.

For those wanting to do the same: The trick is to plug the card into the spare mini PCIe slot and not the WLAN card slot. This way the BIOS will not complain about unsuproted hardware. The spare slot is meant for a WWAN/UMTS card, but the WLAN antenna cables reach it just fine. It is really simple to do its just 3 screws for the panel and one for the card, plus the antenna plugs.

I bought a Intel Centrino Advanced - N 6200 card (half lenght PCIe) for 20€ and it works perfectly. Though I recomend using a full lenght PCI express card as thats what the slot is made for (I had to fix mine with tape, wich is a lot mare stable than it sounds).

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Comments

[Thomas]

Is it possible to do this from the client-side?

[Nomadic]

I did not find an option to force the realtec card to use only g network.

[Thomas]

I cannot switch to g-only, just to bg-only (without effect - problems are still there)

[Uli]

Thanks for the tip, I'll look for such an adapter. This should probably be a comment, not an answer though

[Thomas]

I'm giving it a try - seems to work quite well for now, let's see how it does for the next days.

[Thomas]

Seems to work fine

[Thomas]

The is the linux-backports-modules-cw-3.3-precise-generic package. I'm giving it a try.

[ocos]

I tried to keep the card working properly, but in the end I could never maintain a stable connection. So I ended up changing wireless cards.

[cauon]

So what you're trying to tell us? Please give a brief conclusion.

[Menachem]

askubuntu.com/questions/205575/…

[Earthliŋ]

I tried the same thing with an Intel Centrino 6205 card without any success. Do you have the AMD or the Intel model? What version is your BIOS?

[Uli]

@user1205935 AMD modell, I'll have to check BIOS later. What didn't work for you? Did the BIOS complain about unsuported Hardware even when it was in the WWAN/UMTS slot?

[Uli]

@user1205935 Well reading what you wrote there The problem might be that you didn't remove the old card, which I did. You can try with the tips postet here: todayifoundout.com/index.php/2010/02/…

[Earthliŋ]

Thanks. I'll have to find some tools for that, then. Curious that a WWAN card is allowed to go there, but a WiFi card doesn't even make it to the BIOS...

[Tobias Schula]

Now I’m on 12.10 on my notebook and the wireless behaves a lot better with stock kernel and drivers, but it still randomly disconnects or doesn’t connect at all when the signal strength is low or when you are in a network with a lot of clients.

[Sergey Telshevsky]

I'm not able to download compat-wireless-3.5.1.1-snpc.tar.bz2 every link pointing to the orbit-lab.org is forbidden for me except their homepage and links from it, how may I get this file?