在 Ubuntu 16.04 中重启后 WiFi 不工作

Question

我最近从Ubuntu 14.04 LTS升级到Ubuntu 16.04 LTS。我纠正了phpmyadmin和MySQL-Server的一些问题。但是每当我重新启动系统时，我就会失去互联网连接。尽管 WiFi 显示已启用，但在System Settings > Networks 中看到时，它显示所有路由器都超出范围。

我尝试停止然后使用笔记本电脑上的 WiFi 按钮重新启动 WiFi。但它没有用。

我也尝试从这个答案中给出的终端执行此操作。它也没有奏效。命令如下：

sudo service network-manager restart

另外，试过这个答案。它也没有用。命令如下：

sudo systemctl restart NetworkManager.service

的输出sudo lshw -class network如下：

*-network               
       description: Ethernet interface
       product: RTL8101/2/6E PCI Express Fast/Gigabit Ethernet controller
       vendor: Realtek Semiconductor Co., Ltd.
       physical id: 0
       bus info: pci@0000:08:00.0
       logical name: eth0
       version: 07
       serial: 14:58:d0:c1:1e:d0
       size: 10Mbit/s
       capacity: 100Mbit/s
       width: 64 bits
       clock: 33MHz
       capabilities: pm msi pciexpress msix vpd 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-1_0.0.1 06/29/12 latency=0 link=no multicast=yes port=MII speed=10Mbit/s
       resources: irq:58 ioport:3000(size=256) memory:b2600000-b2600fff memory:b2400000-b2403fff
  *-network
       description: Wireless interface
       product: RT3290 Wireless 802.11n 1T/1R PCIe
       vendor: Ralink corp.
       physical id: 0
       bus info: pci@0000:09:00.0
       logical name: wlan0
       version: 00
       serial: b0:10:41:7f:5c:b5
       width: 32 bits
       clock: 33MHz
       capabilities: pm msi pciexpress bus_master cap_list ethernet physical wireless
       configuration: broadcast=yes driver=rt2800pci driverversion=3.13.0-77-generic firmware=0.37 ip=192.168.1.102 latency=0 link=yes multicast=yes wireless=IEEE 802.11bgn
       resources: irq:16 memory:b2510000-b251ffff