Non 3GPP Wireless Access Technologies: WiFi & WiMAX

Trusted & Un-trusted Non-3GPP Access Technologies (e.g. WiMAX & WiFi)

As you (should really) know that SAE (System Architecture Evolution), also know as EPC (Evolved Packet core), the common core network defined in 3GPP Rel 8, supports all types of access networks, be it radio or fixed line, 3GPP such as PSTN, 2G, 3G, 4G LTE or non 3GPP technologies such as WiMAX, WiFi, etc.

SAE further subdivides Non 3GPP technologies into two types:

• Trusted Non 3GPP, e.g WiMAX
• Un-Trusted Non 3GPP, e.g. WiFi

Why is this classification? Let’s try to answer, but you need understand the basics first:

As wireless transmission became popular, IEEE formed a committee in 1990 called 802.11 to establish standards for WLAN (Wireless LAN). The committee produced its first WLAN standard called 802.11, followed by a long list of standards with various enhancements. Below is a summary of the relevant ones. The two most commonly known WLAN set of standards are WiFi & WiMAX.

WiFi:     The group of standards 802.11a, 11b, 11g, & 11n is called WiFi. It’s coverage is within few meters and hence WiFi is commonly used in a building. It is commonly used in mobile phones, home/small LAN networks & related home appliances.

802.11a – (rectified: 1999), 54 Mbps max speed, working at 5 GHz frequency band, it uses regulated (Licensed) radio spectrum hence developing it incurs licensing fees. It’s use is more popular in office equipment.

802.11b – (1999), 11 Mbps max speed, unregulated 2.4 GHz band, so interference is possible. No license required hence cost is low. Signal range is good and is not easily obstructed because of its use of low band frequency. It is more popular in home appliances.

802.11g – (2003), 54 Mbps max speed, 2.4 GHz band: a newer standard which provides benefits from both of its predecessors. May face some interference from other home appliances due to the use of same unregulated radio spectrum as of 802.11b.

802.11n – (2009) 100+ Mbps, improvements over 802.11g, makes use of MIMO (multiple antennas).

WiMAX: A wireless access technology (similar to local loop), designed for long range, perhaps for miles so can cover a whole city. Oficially called WirelessMAN, it is:

–          Developed by 802.16 committee (not 802.11)

–          Developed for MAN (Metropolitan Area Network) rather than LAN.

–          It has three licensed radio spectrums: 2.3 GHz, 2.5 GHz & 3.5 GHz, but may also work in an unlicensed spectrum of 5.x GHz.

WiMAX has two flavors:

– 802.16-2004 (also known as 802.16d or fixed wireless): It is the originally developed standard, & does not support mobility.

– 802.16-2005 (also known as 802.16e or mobile wireless): It supports mobility. Maybe used for a moving mobile, theoretical data rates up to 70 Mb/s but practically around 10 Mb/s.

What about Bluetooth for LAN???

Bluetooth: Uses unlicensed 2.4 GHz band, formed by 802.15 committee. But Low data rate of approx 1 Mb/s & low range of up to 10 meters only makes it almost impossible to use for WLAN. Commonly used in low powered devices such as mobiles, laptops, etc due to its low cost of manufacturing.

Now, do you understand why is WiMAX is trusted but not WiFi?

The answer is simple, WiMAX uses licensed radio spectrum! So only licensed Service Providers can us it which are trusted. Whereas WiFi is used by any Joe Blog. As a matter of fact WiFi is used in almost every building nowdays freely to setup a home wireless network.

Link to more detailed article: http://compnetworking.about.com/cs/wireless80211/a/aa80211standard.htm