Ubuntu-Wireless bağlantı sorunu

[Exom]

Hem forumda hem de google'da epey bir araştırma yaptım ancak sorunumu çözemedim.
Sorunum wireless bağlantımın sürekli kesiliyor olması.Bağlantı koptuktan sonra adaptörün usb girişinin fişini çekiyorum bir süre bekledikten sonra internete tekrar bağlanıyorum.Bir iş gününde aşağı yukarı 10-15 kez bu durumu yaşıyorum.Yardımcı olursanız sevinirim.Şimdiden teşekkürler.

İs:Ubuntu 7.10
Wireless adaptor:Edimax 7318ug

dhclient.conf:

# Configuration file for /sbin/dhclient, which is included in Debian's
#    dhcp3-client package.
#
# This is a sample configuration file for dhclient. See dhclient.conf's
#    man page for more information about the syntax of this file
#    and a more comprehensive list of the parameters understood by
#    dhclient.
#
# Normally, if the DHCP server provides reasonable information and does
#    not leave anything out (like the domain name, for example), then
#    few changes must be made to this file, if any.
#

send host-name "<hostname>";
#send dhcp-client-identifier 1:0:a0:24:ab:fb:9c;
#send dhcp-lease-time 3600;
#supersede domain-name "fugue.com home.vix.com";
prepend domain-name-servers 212.156.4.1, 212.156.4.4;
request subnet-mask, broadcast-address, time-offset, routers,
    domain-name, domain-name-servers, host-name,
    netbios-name-servers, netbios-scope;
#require subnet-mask, domain-name-servers;
timeout 30;
#retry 60;
#reboot 10;
#select-timeout 5;
#initial-interval 2;
#script "/etc/dhcp3/dhclient-script";
#media "-link0 -link1 -link2", "link0 link1";
#reject 192.33.137.209;

#alias {
#  interface "eth0";
#  fixed-address 192.5.5.213;
#  option subnet-mask 255.255.255.255;
#}

#lease {
#  interface "eth0";
#  fixed-address 192.33.137.200;
#  medium "link0 link1";
#  option host-name "andare.swiftmedia.com";
#  option subnet-mask 255.255.255.0;
#  option broadcast-address 192.33.137.255;
#  option routers 192.33.137.250;
#  option domain-name-servers 127.0.0.1;
#  renew 2 2000/1/12 00:00:01;
#  rebind 2 2000/1/12 00:00:01;
#  expire 2 2000/1/12 00:00:01;
#}

lspci çıktısı:

00:00.0 Host bridge: Intel Corporation 82945G/GZ/P/PL Memory Controller Hub (rev 81)
00:01.0 PCI bridge: Intel Corporation 82945G/GZ/P/PL PCI Express Root Port (rev 81)
00:1b.0 Audio device: Intel Corporation 82801G (ICH7 Family) High Definition Audio Controller (rev 01)
00:1c.0 PCI bridge: Intel Corporation 82801G (ICH7 Family) PCI Express Port 1 (rev 01)
00:1c.2 PCI bridge: Intel Corporation 82801G (ICH7 Family) PCI Express Port 3 (rev 01)
00:1d.0 USB Controller: Intel Corporation 82801G (ICH7 Family) USB UHCI Controller #1 (rev 01)
00:1d.1 USB Controller: Intel Corporation 82801G (ICH7 Family) USB UHCI Controller #2 (rev 01)
00:1d.2 USB Controller: Intel Corporation 82801G (ICH7 Family) USB UHCI Controller #3 (rev 01)
00:1d.3 USB Controller: Intel Corporation 82801G (ICH7 Family) USB UHCI Controller #4 (rev 01)
00:1d.7 USB Controller: Intel Corporation 82801G (ICH7 Family) USB2 EHCI Controller (rev 01)
00:1e.0 PCI bridge: Intel Corporation 82801 PCI Bridge (rev e1)
00:1f.0 ISA bridge: Intel Corporation 82801GB/GR (ICH7 Family) LPC Interface Bridge (rev 01)
00:1f.2 IDE interface: Intel Corporation 82801GB/GR/GH (ICH7 Family) SATA IDE Controller (rev 01)
00:1f.3 SMBus: Intel Corporation 82801G (ICH7 Family) SMBus Controller (rev 01)
01:00.0 VGA compatible controller: nVidia Corporation NV43 [GeForce 6600] (rev a2)
03:00.0 Ethernet controller: Broadcom Corporation NetLink BCM5789 Gigabit Ethernet PCI Express (rev 11)
04:06.0 RAID bus controller: Integrated Technology Express, Inc. IT/ITE8212 Dual channel ATA RAID controller (rev 13)

iwconfig çıktısı:

iwconfig
lo        no wireless extensions.

eth0      no wireless extensions.

wmaster0  no wireless extensions.

wlan0     IEEE 802.11g  ESSID:"bağlandığım ağın adı"  
          Mode:Managed  Frequency:2.437 GHz  Access Point: 00:13:64:22:54:E3   
          Retry min limit:7   RTS thr:off   Fragment thr=2346 B   
          Link Signal level=-64 dBm  
          Rx invalid nwid:0  Rx invalid crypt:0  Rx invalid frag:0
          Tx excessive retries:0  Invalid misc:0   Missed beacon:0

etc/network/interfaces dosyası:

auto lo
iface lo inet loopback

auto rausb0
iface rausb0 inet dhcp

[tasy]

modemin ayarlarından kira süresi olabilir. mesela bir ipe 3 saat müddet verir ve o makine 3 saat sonra internete giremez. böyle birşey olabilir. Benimki sadece bir fikir