我只能看到一个网络，信号强度非常弱，我也无法连接到该网络。详情请见下文。
~$ cat /etc/*release* | grep -i distrib
DISTRIB_ID=Ubuntu
DISTRIB_RELEASE=14.04
DISTRIB_CODENAME=trusty
DISTRIB_DESCRIPTION="Ubuntu 14.04 LTS"
$ lspci | grep -i bcm
08:00.0 Network controller: Broadcom Corporation BCM43142 802.11b/g/n (rev 01)
$ lshw -c network
WARNING: you should run this program as super-user.
*-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: 9c:ad:97:cb:e8:9d
width: 64 bits
clock: 33MHz
capabilities: bus_master cap_list ethernet physical wireless
configuration: broadcast=yes driver=wl0 driverversion=6.30.223.141 (r415941) latency=0 multicast=yes wireless=IEEE 802.11abg
resources: irq:18 memory:b5500000-b5507fff
*-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: 08
serial: 8c:dc:d4:6e:a2:f3
size: 10Mbit/s
capacity: 100Mbit/s
width: 64 bits
clock: 33MHz
capabilities: 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=rtl8106e-2_0.0.1 04/23/13 latency=0 link=no multicast=yes port=MII speed=10Mbit/s
resources: irq:60 ioport:4000(size=256) memory:b5404000-b5404fff memory:b5400000-b5403fff
*-network
description: Ethernet interface
physical id: 1
logical name: usb0
serial: e2:23:b0:d2:86:80
capabilities: ethernet physical
configuration: broadcast=yes driver=rndis_host driverversion=22-Aug-2005 firmware=RNDIS device ip=192.168.42.181 link=yes multicast=yes
WARNING: output may be incomplete or inaccurate, you should run this program as super-user.
$ rfkill list
0: phy0: Wireless LAN
Soft blocked: no
Hard blocked: no
1: brcmwl-0: Wireless LAN
Soft blocked: no
Hard blocked: no
$ ifconfig
eth0 Link encap:Ethernet HWaddr 8c:dc:d4:6e:a2:f3
UP BROADCAST MULTICAST MTU:1500 Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:0 (0.0 B) TX bytes:0 (0.0 B)
lo Link encap:Local Loopback
inet addr:127.0.0.1 Mask:255.0.0.0
inet6 addr: ::1/128 Scope:Host
UP LOOPBACK RUNNING MTU:65536 Metric:1
RX packets:1777 errors:0 dropped:0 overruns:0 frame:0
TX packets:1777 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:171412 (171.4 KB) TX bytes:171412 (171.4 KB)
usb0 Link encap:Ethernet HWaddr e2:23:b0:d2:86:80
inet addr:192.168.42.181 Bcast:192.168.42.255 Mask:255.255.255.0
inet6 addr: fe80::e023:b0ff:fed2:8680/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:10720 errors:1 dropped:0 overruns:0 frame:1
TX packets:12968 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:5448768 (5.4 MB) TX bytes:2178541 (2.1 MB)
wlan0 Link encap:Ethernet HWaddr 9c:ad:97:cb:e8:9d
inet6 addr: fe80::9ead:97ff:fecb:e89d/64 Scope:Link
UP BROADCAST MULTICAST MTU:1500 Metric:1
RX packets:8 errors:0 dropped:0 overruns:0 frame:2664
TX packets:66 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:1393 (1.3 KB) TX bytes:15322 (15.3 KB)
Interrupt:18
~$ sudo apt-get install bcmwl-kernel-source
Reading package lists... Done
Building dependency tree
Reading state information... Done
bcmwl-kernel-source is already the newest version.
0 upgraded, 0 newly installed, 0 to remove and 385 not upgraded.
请帮助我解决 Wi-fi 问题。如果您需要更多信息，请在此处发表评论。
答案1
可能不是最好的解决方案：你可以尝试增加 wifi 适配器的功率，正如它所写这里。 （不过要小心。）
答案2
在 Linux Mint 17.1 上使用 Broadcom 43142 卡时，我的 Asus K555LN 的 WIFI 信号弱且不稳定。
只需运行此命令即可解决问题，如此线程中建议的那样Ubuntu 14.04 (Trusty Tahr) 上的 Broadcom BCM43142 驱动程序
# (sudo rmmod b43 ; sudo rmmod bcma ; sudo rmmod wl ; sudo modprobe wl ; sudo modprobe lib80211_crypt_tkip)