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Old 11-20-2010, 02:22 PM   #1
shane601
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BCM4313 cannot achieve 802.11n speed


I can only get speeds of 8Mb/s wifi with my new Dell Studio XPS 1645 with the Broadcom STA proprietary driver.

Is there a way to change the bitrate so that I can use full speed of Wireless N?


I've tried using iwconfig to specify the bitrate without an effect.
iwconfig eth1 rate 54M auto
iwconfig eth1 rate 300M auto


I'm using Ubuntu 10.10 64bit 2.6.35-22

$ dmesg | grep BCM
Code:
[   18.283393] eth1: Broadcom BCM4727 802.11 Hybrid Wireless Controller 5.60.48.36
$ lspci -nn| grep BCM
Code:
05:00.0 Network controller [0280]: Broadcom Corporation BCM4313 802.11b/g LP-PHY [14e4:4727] (rev 01)
$ iwconfig
Code:
eth1      IEEE 802.11  ESSID:"********"  
          Mode:Managed  Frequency:2.437 GHz  Access Point: E0:CB:4E:3B:A0:CE   
          Bit Rate=8 Mb/s   Tx-Power:24 dBm   
          Retry min limit:7   RTS thr:off   Fragment thr:off
          Encryption key:off
          Power Management:off
          Link Quality=5/5  Signal level=-42 dBm  Noise level=-91 dBm
          Rx invalid nwid:0  Rx invalid crypt:0  Rx invalid frag:0
 
Old 11-20-2010, 05:12 PM   #2
business_kid
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They are not speed kings. Get used to it.
(Sent on a 4312)
 
Old 11-20-2010, 05:19 PM   #3
minrich
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According to your lspci output the BCM4313 doesn't support 'n' only b/g.

HTH
 
Old 11-20-2010, 05:46 PM   #4
shane601
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Seems like the driver may be incorrectly recognizing it. According to Dell the card Dell 1501 Half Mini-Card (4313bgn).

Regardless I should at least get 54Mb/s. Is there some config option for iwconfig to force 802.11g?
 
Old 11-20-2010, 06:09 PM   #5
minrich
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Are you connecting to your own wifi router? If so, and without knowing who made it, you should be able to set it to only use 'n' (that is if it is capable of 'n' speeds). You could ascertain this by running the command:

iwlist wlan0 scan

You may have to change 'wlan0' to the interface name that you get returned from: ifconfig -a

HTH
 
Old 11-20-2010, 08:48 PM   #6
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You need to ensure your router supports the speed you want to use.
 
Old 11-21-2010, 04:30 AM   #7
business_kid
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All these theoretical comments are wonderful.

What is also true is that unless you are sitting on your router, none of these speeds are guaranteed. As a techie who has spent time supporting tvs and other radio systems, I'm in a position to underline that.
I had a guy once who couldn't get any output (on a 2ghz channel) from one room to the next. I eventually discovered the wall between them was 2 feet thick (0.55metres) :-/. Many others (less notably stupid) people also failed, for various reasons. The product was a video sender, which sent sound & video from a satellite scart to a second telly in the house. My approach was always the same. Put router & laptop on the same table top, & experiment with speed. Then back off distance & repeat.
 
Old 11-21-2010, 11:09 AM   #8
shane601
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I understand that I'm not _guaranteed_ a super-fast connection but I should get better than 802.11b speeds.

At home I am next to a computer that gets decent 802.lln speeds (on an asus usb-n-13 Ubuntu 10.04). Also I've tried within 1 meter of my router.

At work I sit next another Ubuntu 10.10 workstation using wireless n on an older Dell Studio XPS. His card is intel based so he had to enable 802.11n in /etc/modprobe.d/intel-5300-iwlagn-disable11n.conf
I have modified this file as well, without any changes.

Before installing Ubuntu I believe that I was able to get very fast speeds from Windows 7 install (I was uninstalling the windows software that supposedly corrupts grub2 boot.)

Any other ideas?
 
Old 11-21-2010, 11:39 AM   #9
shane601
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Here is a iwlist from my BCM4313 card:
Code:
eth1      Scan completed :
          Cell 01 - Address: E0:CB:4E:3B:A0:CE
                    ESSID:"********"
                    Mode:Managed
                    Frequency:2.437 GHz (Channel 6)
                    Quality:5/5  Signal level:-44 dBm  Noise level:-85 dBm
                    IE: IEEE 802.11i/WPA2 Version 1
                        Group Cipher : TKIP
                        Pairwise Ciphers (2) : CCMP TKIP
                        Authentication Suites (1) : PSK
                    Encryption key:on
                    Bit Rates:1 Mb/s; 2 Mb/s; 5.5 Mb/s; 11 Mb/s; 18 Mb/s
                              24 Mb/s; 36 Mb/s; 54 Mb/s; 6 Mb/s; 9 Mb/s
                              12 Mb/s; 48 Mb/s
Here is a iwlist from my ASUS N-13 card in another computer. (aprox 15 meters away)
Code:
ra0       Scan completed :
          Cell 01 - Address: E0:CB:4E:3B:A0:CE
                    Protocol:802.11b/g/n
                    ESSID:"********"
                    Mode:Managed
                    Frequency:2.437 GHz (Channel 6)
                    Quality:78/100  Signal level:-59 dBm  Noise level:-92 dBm
                    Encryption key:on
                    Bit Rates:144 Mb/s
                    IE: IEEE 802.11i/WPA2 Version 1
                        Group Cipher : TKIP
                        Pairwise Ciphers (2) : CCMP TKIP
                        Authentication Suites (1) : PSK
 
  


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