Conexão wifi muito lenta Ubuntu 15.04

Question

Eu comprei recentemente um laptop e instalei o novo Ubuntu nele, inicialização dupla com o Windows 8. No Windows eu tenho uma conexão wi-fi muito decente e o sinal é sempre alto. No entanto, no Ubuntu no mesmo local em minha casa eu só tenho 1 ou 2 bares. Eu tentei postar seu número, mas parece que não tenho extensões sem fio no iwconfig

eth0      no wireless extensions.

wlan0     IEEE 802.11abg  ESSID:"amiraratoud"  
          Mode:Managed  Frequency:2.412 GHz  Access Point: 94:FB:B3:F9:94:2D   
          Retry short limit:7   RTS thr:off   Fragment thr:off
          Power Management:on

lo        no wireless extensions.

Resultados de

e lspci:

00:00.0 Host bridge: Intel Corporation Broadwell-U Host Bridge -OPI (rev 09)
00:02.0 VGA compatible controller: Intel Corporation Broadwell-U Integrated Graphics (rev 09)
00:03.0 Audio device: Intel Corporation Broadwell-U Audio Controller (rev 09)
00:04.0 Signal processing controller: Intel Corporation Broadwell-U Camarillo Device (rev 09)
00:14.0 USB controller: Intel Corporation Wildcat Point-LP USB xHCI Controller (rev 03)
00:16.0 Communication controller: Intel Corporation Wildcat Point-LP MEI Controller #1 (rev 03)
00:1b.0 Audio device: Intel Corporation Wildcat Point-LP High Definition Audio Controller (rev 03)
00:1c.0 PCI bridge: Intel Corporation Wildcat Point-LP PCI Express Root Port #1 (rev e3)
00:1c.1 PCI bridge: Intel Corporation Wildcat Point-LP PCI Express Root Port #2 (rev e3)
00:1c.2 PCI bridge: Intel Corporation Wildcat Point-LP PCI Express Root Port #3 (rev e3)
00:1c.3 PCI bridge: Intel Corporation Wildcat Point-LP PCI Express Root Port #4 (rev e3)
00:1c.4 PCI bridge: Intel Corporation Wildcat Point-LP PCI Express Root Port #5 (rev e3)
00:1f.0 ISA bridge: Intel Corporation Wildcat Point-LP LPC Controller (rev 03)
00:1f.2 SATA controller: Intel Corporation Wildcat Point-LP SATA Controller [AHCI Mode] (rev 03)
00:1f.3 SMBus: Intel Corporation Wildcat Point-LP SMBus Controller (rev 03)
08:00.0 Network controller: Broadcom Corporation BCM43142 802.11b/g/n (rev 01)
09:00.0 Ethernet controller: Realtek Semiconductor Co., Ltd. RTL8101E/RTL8102E PCI Express Fast Ethernet controller (rev 0a)
0a:00.0 3D controller: NVIDIA Corporation Device 1347 (rev a2)

Resultados da rede

e lshw -class:

  *-network               
       description: Wireless interface
       product: BCM43142 802.11b/g/n
       vendor: Broadcom Corporation
       physical id: 0
       bus info: pci@0000:08:00.0
       logical name: wlan0
       version: 01
       serial: d8:5d:e2:b8:12:0f
       width: 64 bits
       clock: 33MHz
       capabilities: pm msi pciexpress bus_master cap_list ethernet physical wireless
       configuration: broadcast=yes driver=wl0 driverversion=6.30.223.248 (r487574) ip=*.*.*.* latency=0 multicast=yes wireless=IEEE 802.11abg
       resources: irq:18 memory:c6100000-c6107fff
  *-network
       description: Ethernet interface
       product: RTL8101E/RTL8102E PCI Express Fast Ethernet controller
       vendor: Realtek Semiconductor Co., Ltd.
       physical id: 0
       bus info: pci@0000:09:00.0
       logical name: eth0
       version: 0a
       serial: 94:57:a5:d6:b7:0f
       size: 10Mbit/s
       capacity: 100Mbit/s
       width: 64 bits
       clock: 33MHz
       capabilities: pm msi pciexpress msix bus_master cap_list ethernet physical tp mii 10bt 10bt-fd 100bt 100bt-fd autonegotiation
       configuration: autonegotiation=on broadcast=yes driver=r8169 driverversion=2.3LK-NAPI duplex=half firmware=rtl8107e-2_0.0.2 02/26/15 latency=0 link=no multicast=yes port=MII speed=10Mbit/s
       resources: irq:49 ioport:4000(size=256) memory:c6004000-c6004fff memory:c6000000-c6003fff