Wi-Fi продолжает отключаться

У меня dell vostro 2520. Когда я пытаюсь загрузить огромные файлы или когда я просто смотрю видео на YouTube, отключается Wi-Fi. У меня была такая же проблема на предустановленных Windows 8 тоже. Я думал, что если я установлю Ubuntu 14.04, это решит проблему, поэтому я стер Windows и установил Ubuntu, но проблема все еще существует.

это вывод lspci:

00:00.0 Host bridge: Intel Corporation 2nd Generation Core Processor Family DRAM Controller (rev 09)
00:02.0 VGA compatible controller: Intel Corporation 2nd Generation Core Processor Family Integrated Graphics Controller (rev 09)
00:16.0 Communication controller: Intel Corporation 7 Series/C210 Series Chipset Family MEI Controller #1 (rev 04)
00:1a.0 USB controller: Intel Corporation 7 Series/C210 Series Chipset Family USB Enhanced Host Controller #2 (rev 04)
00:1b.0 Audio device: Intel Corporation 7 Series/C210 Series Chipset Family High Definition Audio Controller (rev 04)
00:1c.0 PCI bridge: Intel Corporation 7 Series/C210 Series Chipset Family PCI Express Root Port 1 (rev c4)
00:1c.3 PCI bridge: Intel Corporation 7 Series/C210 Series Chipset Family PCI Express Root Port 4 (rev c4)


00:1c.5 PCI bridge: Intel Corporation 7 Series/C210 Series Chipset Family PCI Express Root Port 6 (rev c4)
00:1d.0 USB controller: Intel Corporation 7 Series/C210 Series Chipset Family USB Enhanced Host Controller #1 (rev 04)
00:1f.0 ISA bridge: Intel Corporation HM75 Express Chipset LPC Controller (rev 04)
00:1f.2 SATA controller: Intel Corporation 7 Series Chipset Family 6-port SATA Controller [AHCI mode] (rev 04)
00:1f.3 SMBus: Intel Corporation 7 Series/C210 Series Chipset Family SMBus Controller (rev 04)
07:00.0 Network controller: Broadcom Corporation BCM43142 802.11b/g/n (rev 01)
09:00.0 Ethernet controller: Realtek Semiconductor Co., Ltd. RTL8111/8168/8411 PCI Express Gigabit Ethernet Controller (rev 07)

    this is the wifi section from the output of lshw command:

    *-network
    description: Wireless interface
    product: BCM43142 802.11b/g/n
    vendor: Broadcom Corporation
    physical id: 0
    bus info: pci@0000:07:00.0
    logical name: wlan0
    version: 01
    serial: 9c:2a:70:bd:d9:fb
    width: 64 bits
    clock: 33MHz
    capabilities: bus_master cap_list ethernet physical wireless
    configuration: broadcast=yes driver=wl0 driverversion=6.30.223.248 (r487574) ip=XXX.XXX.X.X latency=0 multicast=yes wireless=IEEE 802.11abg
    resources: irq:19 memory:f7c00000-f7c07fff