Communication Networks/Wireless Internet

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Communication Networks

There are 2 different protocols that are prominent in the field of wireless internet: WiFi and WiMAX.

Contents 1 WiFi (IEEE 802.11) 1.1 802.11a 1.2 802.11b 1.3 802.11g 1.4 802.11n 2 WiMax (IEEE 802.16)

[edit] WiFi (IEEE 802.11)

Wifi simply stands for Wireless Fidelity.

[edit] 802.11a

What is 802.11a and history of 802.11a?

It is a Wireless LAN standard from the IEEE(Institute of Electronics and Electrical Engineers). It was released on October 11th in 1999.

Speed:

It can achieve a maximum speed of 54Mbps. Although the typical data rate transfer is at 22Mbps. If there is a need the data rate will be reduced to 48, 36, 24, 18, 12, 9 then 6Mbps respectively. This usually occurs as the distance between the access point or the wireless router and the computer gets further and further away.

Frequency:

It operates under the 5Ghz frequency band. The advantage of this is that it has lesser interference compared to the 802.11b and 802.11g standards, which operate at 2.4Ghz. It means that quite a number of electronic equipment use this frequency band such as microwaves, cordless phones, bluetooth devices etc. Therefore, the more electronic equipment that use the same frequency band, the more interferences it will cause among the equipment that are using that frequency band.

Interoperability:

802.11a will not operate readily with 802.11b or 802.11g due to the different frequency bands unless the equipment implements the both standards. E.g. Equipment that use both 802.11a and 802.11g standards.

Number of Channels

It has 12 non-overlapping channels. 8 are for indoor(within the area) and the other 4 are for point to point.

[edit] 802.11b

What is 802.11b and its history

It is also something like 802.11a. It is of course a wireless standard made by IEEE and guess what it was implemented on the same month and year as 802.11a which was in 0ctober 1999.

Speed

802.11b has the lowest speed after 802.11 legacy. It can reach a maximum speed of only 11 Mbps.

Frequency

[edit] 802.11g

[edit] 802.11n

[edit] WiMax (IEEE 802.16)