Wireless Networking Protocols | CompTIA A+ 220-1001 | 2.4

In this video we will be discussing wireless networking protocols such as:Β  802.11a/b/g/n/ac wireless networks, frequencies, channels, MIMO, Bluetooth, NFC, RFID, Zigbee, Z-Wave, 3G, 4G, 5G, LTE.

WiFi Standards

The 5 WiFi standards:

  • 802.11b: maximum speed of 11Mbps operating in the 2.4GHz frequency band with a maximum indoor range of 35m.
  • 802.11a: maximum speed of 54Mbps using the 5GHz frequency band with a maximum indoor range of 35m.
  • 802.11g: maximum speed of 54Mbps operating in the 2.4GHz frequency band with a maximum indoor range of 45m.  It is backward compatible with 802.11b.
  • 802.11n: maximum speed of 150Mbps when using a single 20MHz channel, or it can run at up to 300Mbps with channel bonding (40MHz channel).  Operates in the 2.4GHz frequency by default, but it can also support 5GHz frequencies as well.  802.11n has a maximum indoor range of 70m. Supports MIMO (multiple input multiple output) antennas to improve performance and range, although not all devices include multiple antennas.
  • 802.11ac: uses only the 5GHz band and supports up to 80MHz-wide channels compared to 20MHz for 802.11b/g and 40MHz for 802.11n using channel bonding.  Supports multiuser MIMO (MU-MIMO).  The speed of 802.11ac is up to 433Mbps per stream when 80MHz-wide channels are used.
Wireless Ethernet Standards

Wireless Frequency Differences

Wireless routers can use either the 2.4GHz or the 5GHz frequency band and a lot of wireless routers offer both frequencies that can be configured separately. Some routers are even capable of switched between the two frequencies automatically if a signal becomes weak.  Each has advantages & disadvantages such as:

  • The 2.4GHz band performs at slower speeds but has a longer range
    • Lower frequencies tend to travel better through obstacles such as walls & floors
  • The 2.4GHz is used more often but has more channels that do overlap that can cause interference
  • The 5GHz band performs at faster rates but typically has a shorter range
  • The 5GHz band is less used and has more channels that do not overlap
2.4GHz vs. 5GHz Wireless Bands

Understanding MIMO (Multiple Input & Multiple Output)

MIMO is a method for multiplying the capacity of a radio link using multiple transmission and receiving antennas to exploit multipath propagation. MIMO has become an essential element of wireless communication standards including IEEE 802.11n & 802.11ac. Some smartphones and tablets simply use the term MIMO (multiple input multiple output) if they support two or more 802.11n or 802.11ac streams. MIMO devices are available in the following configurations:

  • 1×1:  One transmit, one receive antenna
  • 2×2:  Two transmit, two receive antennas
  • 2×3:  Two transmit, three receive antennas
  • 3×2:  Three transmit, two receive antennas
  • 3×3:  Three transmit, three receive antennas

The number of transmit antennas typically corresponds to the number of data streams (spatial streams) the device can support.  In the case of a router that supports both 2.4GHz and 5GHz signals, the specifications include this information for each band. Devices that have different numbers of receiving antennas and sending antennas may be identified by the number of data streams it can send and receive.  For example, a device with a 2×3 antenna configuration can also be identified as having a 2×3:2 configuration (two send antennas, three receive antennas, and send/receive support for two data streams).


Bluetooth is a wireless technology standard used for exchanging data between fixed and mobile devices over short distances using short wavelength UHF (ultra high frequency) radio waves in the industrial, scientific & medical radio bands, from the 2.4GHz band, and building personal area networks (PANs).  Bluetooth runs in virtually the same 2.4GHz frequency used by IEEE 802.11b, 802.11g, and 802.11n wireless networks but uses a spread-spectrum frequency-hopping signaling method to help minimize interference. Bluetooth can be used to do the following:

  • Connect to wireless speakers, mice, keyboards, printers, and game controllers
  • Transfer files between devices
  • Control home security or automation devices
  • Integrate your smartphone with your car’s audio or navigation system

Bluetooth versions:

  • Version 1.2 offers a data transfer rate of 1Mbps
  • Version 2 offers 3Mbps
  • Version 3.0 + HS offers speeds up to 24Mbps because it uses Bluetooth only to establish a connection, and the actual data transfer happens over an 802.11 link
    • Feature is known as Alternative MAC/PHY (AMP)
  • Version 4.0 (Bluetooth Smart) is designed for use with very low-power applications such as sensors
  • Version 4.1 (software update to 4.0) enables Bluetooth to perform multiple roles at the same time & to work with LTE cellular devices
  • Version 4.2 includes additional features to support IoT
  • Version 5.0 was designed specifically with IoT in mind
Bluetooth Power/Distance Classes

The most common Bluetooth devices are Class 2 devices such as printers, headsets, computer dongles, etc. To connect a Bluetooth device to a mobile device, Bluetooth needs to be enabled. Then the Bluetooth device needs to be synchronized (paired or linked) to the mobile device.  Sometimes the synchronization process requires a PIN code.  Once synchronized, the device needs to be connected.  Finally, the Bluetooth connection should be tested.

Configuring a Bluetooth Headset on an Android-Based Device

Steps to connect a Bluetooth headset to a typical Android-based device:

  1. Go to Settings > Connections and then enable Bluetooth.
  2. Tap Bluetooth for Bluetooth Settings screen.
  3. Prepare the headset by simply powering it on to begin the pairing process (this step can vary).
  4. Tap Scan if the headset is not already scanning & keep holding the button on the headset until the Android device finds it.
  5. On the Android device, tap the device to pair with.
  6. Enter a PIN code, if prompted to do so.  Many devices come with the default pin 0000.

To disconnect the device but retain the pairing, turn off the device.  To unpair the device, tap the settings (gearbox) icon on the screen and tap Unpair.  To use it again, pair it again.

Android Bluetooth Screen

Configuring a Bluetooth Headset on an iOS Device

Steps to connect a Bluetooth headset to a typical iOS device:

  1. Go to Settings and then tap Bluetooth.
  2. Tap Bluetooth to initiate the iOS device to search for other devices.
  3. Prepare the headset by simply powering it on to begin the pairing process (this step can vary).
  4. Tap the device name, and it automatically connects.
  5. Enter a PIN code, if prompted to do so.

To remove the device, tap it.  One the next screen, tap Forget This Device.  To stop using the device but keep it paired, tap Disconnect. Be mindful that most Bluetooth devices can be connected to only one mobile device at a time.

iOS Bluetooth Screen


Near-field communication is a set of communication protocols that enable 2 electronic devices, one of which is usually a portable device such as a smartphone, to establish communication by bringing them within 4 cm of each other.  NFC enables smartphones to be used for payment services such as Apple Pay, Samsung Pay, and Android Pay. NFC also enables file transfer between supported devices. To transfer files between smartphones with NFC, both smartphones must have NFC enabled and an NFC file transfer utility (sometimes referred to as “tap and go”) enabled, such as S Beam (Samsung smartphones) or Android Beam (Android smartphones).  Once that is enabled, simply tap the phones together to transfer files. NFC can also be used with compatible printers for tap-to-print capabilities.

RFID (Radio Frequency Identification)

RFID uses electromagnetic fields to automatically identify and track tags attached to objects. An RFID tag consists of a tiny radio transponder; a radio receiver and transmitter. When triggered by an electromagnetic interrogation pulse from a nearby RFID reader device, the tag transmits digital data, usually an identifying inventory number, back to the reader. This number can be used to inventory goods. There are two types:

  • Passive tags: Powered by energy from the RFID reader’s interrogating radio waves.
  • Active tags: Powered by a battery and thus can be read at a greater range from the RFID reader (up to hundreds of meters).

Examples of RFID technology:

  • Security badges that allow doors to be unlocked in a secure environment, giving access to some while denying use to others.
  • Some items for sale have RFID tags used for identifying the item name & price. The badges on the items broadcast their information to a checkout reader which could allow for customers to simply walk out of the door and the items are counted, priced, and paid for by just simply walking past the reader.
  • Passports & other identification documents could also have RFID information embedded in them as well (think of RFID-chipped dog collars to locate missing dogs.

Zigbee and Z-Wave

Zigbee is a low-power, low data rate, and close proximity (PAN…personal area network) wireless ad hoc network. Zigbee is intended to be simpler and less expensive than other wireless PANs, such as Bluetooth or more general wireless networking such as WiFi. Applications include wireless light switches, home energy monitors, traffic management systems, and other consumer and industrial equipment that requires short-range low-rate wireless data transfer. Zigbee operates at the 2.4GHz frequency. Z-Wave is a more recent version of Zigbee that uses less power and operates on the much lower 908.42MHz frequency.  Zigbee and Z-Wave are not interoperable.

3G, 4G, 5G, and LTE

3G, 4G, 5G, & LTE networks are provided from cell towers. The G stands for “generation” and each new generation of network service provides advanced signaling and available services. Most cell phones in use now support 3G, 4G, and LTE. 5G for the most part is still in the development & testing phase.

3G, 4G, 5G, & LTE Comparison