Wireless technologies are the building blocks used to create networks that provide devices with access to the internet and other network resources. The most common application of these technologies is for creating Wireless Local Area Networks (WLANs) and providing mobile internet access through cellular networks.

Mobile devices connecting via wireless networks Figure 1: Wireless Network Connectivity

Wireless Local Area Networks (WLAN)

A WLAN is a network that allows devices to connect and communicate wirelessly within a limited area, such as a home, school, or office building. The most common technology used for WLANs is Wi-Fi.

flowchart TB
    INTERNET(("🌐 Internet"))
    MODEM["📟 Modem"]
    AP["📡 Access Point\n(Wireless Router)\nBroadcasts SSID"]

    subgraph DEVICES["Connected Devices"]
        LAPTOP["💻 Laptop\nWireless NIC"]
        PHONE["📱 Smartphone"]
        TABLET["📱 Tablet"]
        TV["📺 Smart TV"]
    end

    INTERNET --> MODEM --> AP
    AP -.->|"📡 Wi-Fi Signal"| DEVICES

    style AP fill:#1565c0,color:#fff

Figure 1: Wireless Local Area Network (WLAN) Architecture

Key Components of a WLAN:

  1. Access Point (AP): The central device that broadcasts the wireless signal. In most homes, this functionality is built into a wireless router. The AP connects to the wired network infrastructure (e.g., a cable or fiber modem) to gain access to the internet.

  2. Wireless Network Interface Card (NIC): A component inside a device (like a laptop, smartphone, or smart TV) that allows it to communicate with a wireless network. Every device on a WLAN needs a wireless NIC.

  3. SSID (Service Set Identifier): The public name of a wireless network. When you open your device and see a list of available Wi-Fi networks, you are seeing a list of SSIDs being broadcast by nearby access points.

WLAN Security

Because wireless signals are broadcast through the air, security is a major concern. Unauthorized users could potentially access the network or eavesdrop on data being transmitted. To prevent this, WLANs use security protocols that encrypt the data and require a password for access.

  • WEP (Wired Equivalent Privacy): An early and now obsolete protocol with major security flaws.
  • WPA (Wi-Fi Protected Access): An interim improvement over WEP.
  • WPA2: For many years, this was the standard for securing wireless networks.
  • WPA3: The current and most secure protocol, offering stronger encryption and better protection against attacks.

Mobile Internet Access

Wide-area wireless networks, primarily cellular networks, provide internet access to mobile devices like smartphones and tablets.

  • Cellular Data: When you are not connected to Wi-Fi, your smartphone uses the cellular network (e.g., 4G LTE or 5G) to connect to the internet. This allows for continuous connectivity while on the move.

  • Mobile Hotspot (Tethering): Most smartphones have a feature that allows them to act as a portable wireless router. The phone uses its cellular data connection to access the internet and then shares that connection with other nearby devices (like a laptop) by creating its own small Wi-Fi network.

Public Wireless Hotspots

A hotspot is a physical location that offers internet access over a WLAN. These are commonly found in public places like cafes, airports, hotels, and libraries. While they offer great convenience, they also come with security risks.

  • Open Networks: Many public hotspots are “open,” meaning they do not require a password and do not use encryption. When you use an open network, any data you send or receive could potentially be intercepted by a malicious actor on the same network (a “man-in-the-middle” attack).
  • Best Practices: When using public Wi-Fi, it is crucial to avoid sending sensitive information (like passwords or financial details) and to use a Virtual Private Network (VPN). A VPN encrypts all of your internet traffic, creating a secure tunnel that protects your data even on an open network.