Wireless Technologies & Limitations

 

Wireless LAN/Wi-Fi

"Wi-Fi" is a trademark of the Wi-Fi Alliance and the brand name for products using the IEEE 802.11 family of standards. It is also known as wireless LAN (WLAN) and can refer to as any of the established 802.11 standards: 802.11a, 802.11b, 802.11g, 802.11n and 802.11ac. New wireless standards will continue to evolve.

The wireless technology is fast evolving, and consumer needs to be aware of their PC & router capability and limitation, so as to avoid misunderstanding and mismatch in performance expectation and surfing experience.

A device enabled with Wi-Fi, such as a personal computer, video game console, smart phone, or digital audio player, can connect to the Internet via a wireless router that connects to a modem.

The 802.11 family consists of a series of over-the-air modulation techniques that use the same basic protocol.

802.11 Standard 802.11b 802.11g  802.11a 802.11n 802.11ac
Frequency 2.4GHz 2.4GHz 5GHz 2.4GHz 5GHz 5GHz
Allowable MIMO streams     No No No up to 4 streams up to 4 streams up to 8 streams
Data-rate Per Stream 11Mbps 54Mbps 54Mbps 72.2Mbps (20MHz bandwidth) 72.2Mbps (20MHz bandwidth) 433 Mbps (80MHz bandwidth)
150Mbps (40MHz bandwidth) 150Mbps (40MHz bandwidth) 866.7Mbps (160MHz bandwidth)

Factors affecting wireless network connection (speed performance or coverage) 

Wireless signals travel through the atmosphere, they are sensitivity to different types of interference compare to wired network.

  • Physical objects: The number of walls the Wireless signal can pass through is determines by density of the materials used in a building’s construction. Concrete and steel walls are difficult for a signal to pass through. These structures will weaken or at times completely prevent wireless signals.
  • 2.4Ghz Frequency Interference:   
    • Cordless Phone - operates the same frequency as the Wi-Fi standards and can cause a significant decrease in speed, or sometimes the total blocking of the Wi-Fi signal.
    • Microwave Oven - operates by emitting a very high power signal in the 2.4GHz band. Often emits a very "dirty" signal across the entire 2.4GHz band.
    • Wireless Routers – Wireless Network that share the same wireless channel will reduce the wireless speed performances.
  • Shared bandwidth: The bandwidth of wireless network is shared among all the wireless users, so the more users you have, the slower the network becomes. Downloading torrents, for example, might cause other users to experience a slowdown in network speed.
  • Distance: If you're sitting near a wireless router or access point, you will experience a faster network speed. But if another person is sitting far from the wireless router or access point, the network speed of both computers will drop  drastically. 
  • Mixed Network (802.11b/g/n): By connecting to 802.11n wireless adapter alone, you'll be able to get a good network speed. However, once an 802.11g or 802.11b user joins the network, your network connection speed may be slowed by half or more.
  • Locations: Where an AP or wireless router is placed also makes the difference. Place the devices in higher ground to reduce the impact of physical objects.

Actions to improve wireless access

1. Wireless Settings for best throughput between PC and Router:

  • Wireless settings:
    • 802.11 Mode: Mixed 802.11 n/b/g
    • Channel Width: 20/40Mhz (Auto)
  • Wireless Encryption:
    • WPA Mode: Auto (WPA or WPA2)
    • Cipher Type: AES

2. Data Point (Access Point)

  • Deploying Access Points around your home, particularly in existing areas of poor or no coverage, reduces the average distance between a wireless device and its nearest access point, thus increasing the average speed.

3. Wireless Settings for best throughput between PC and Router:

a. Wireless settings:

802.11 Mode: Mixed 802.11 n/b/g
Channel Width: 20/40Mhz (Auto)

b. Wireless Encryption:

WPA Mode: Auto (WPA or WPA2)
Cipher Type: AES

4. Data Point (Access Point)
Deploying Access Points around your home, particularly in existing areas of poor or no coverage, reduces the average distance between a wireless device and its nearest access point, thus increasing the average speed. 

Basic maintenance and troubleshooting of wireless network

1. Change the wireless channel to less “Crowded” channels.

2. Or reboot the router if “Enable Auto Channel Scan” is enabled, the router will scan and assign a new channel during the boot up.

3. Or move the wireless network frequency from 2.4GHz to 5GHz for 802.11a/n.

4. Lastly, user can reset the device to factory default setting by:

a. Hardware Reset

With the router powered on, use a paperclip to hold the button down for 10 seconds.

b. Web GUI Reset

Tool > System

        *Factory reset will erase all the present settings on the router.

NOTE:

  • Generally, the information shared below should be applicable to other models/brands, if they provide the same features/options. The images/information stated here are based on DLInk’s wireless router model DIR865L Please refer to your own router manufacturer to confirm if similar features or recommended actions are supported.

Data Security Risks

As wireless signal may go beyond your home, outsider may be able to access to your wireless LAN if it is not protected (eg. using wireless encryption). Wired Equivalent Privacy (WEP), is the most common wireless encryption-standard, may be more easily breakable even when correctly configured. Wi-Fi Protected Access (WPA and WPA2) encryption, which became available in devices in 2003, aimed to solve this problem.

Dual Band

Dual band refers to the capability to transmit on the 5GHz band of 802.11a and also the 2.4GHz band used by 802.11b, 802.11g, and 802.11n. Ordinary Wi-Fi equipment only supports one signal band, whereas dual-band gear contains two different types of wireless radios and can support connections on both 2.4GHz and 5GHz links.

Dual-band Wi-Fi is a feature of some wireless routers and network adapters.

Dual Band Routers

Ordinary routers only support one wireless signal band, while dual-band routers can support connections on both 2.4GHz and 5GHz links.

Some 802.11n Wi-Fi routers also allow simultaneous dual band communication with both 2.4GHz and 5GHz clients at the same time. These routers provide maximum flexibility in setting up a home network. It allows 802.11b/g/n clients to run on the 2.4GHz side, 802.11a and 802.11n clients can run at 5GHz.

Dual Band Adapters

Dual-band Wi-Fi network adapters likewise contain two wireless radios. These adapters can be configured to use either 802.11a via one radio, or the 802.11b/g/n family via the other, but not both.