A comparison of wi-fi and wimax with case studies - Florida State ...
A comparison of wi-fi and wimax with case studies - Florida State ...
A comparison of wi-fi and wimax with case studies - Florida State ...
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4.3. The Physical Layer <strong>and</strong> MAC Layer<br />
In the follo<strong>wi</strong>ng section, the IEEE 802.16-2004 <strong>and</strong> IEEE 802.16e-2005 <strong>wi</strong>ll be discussed.<br />
IEEE 802.16e-2005 inherits the <strong>fi</strong>xed-BWA ability from IEEE 802.16-2004 <strong>and</strong> re-edits the<br />
PHY <strong>and</strong> MAC layer to combine <strong>fi</strong>xed-BWA <strong>wi</strong>th mobility. According to the WiMax forum,<br />
there are four usage scenarios: nomadic, portable, simple mobility <strong>and</strong> full mobility. The<br />
applications <strong>of</strong> IEEE 802.16-2004 are to provide an air-interface for <strong>fi</strong>xed <strong>and</strong> nomadic<br />
transmission, while IEEE 802.16e-2005 is to provide an air-interface for portable <strong>and</strong> mobile<br />
transmission. [50][59][94] – [96]<br />
Nomadic<br />
The user can use his/her devices <strong>wi</strong>th a local <strong>fi</strong>xed service <strong>and</strong> reconnect to a different <strong>fi</strong>xed<br />
service in another place.<br />
Portable<br />
Provide service for 3G-phones, PDA or notebook.<br />
Simple mobility<br />
Allowed the end users move in the speed up to 60 km/hr <strong>wi</strong>th less than 1 second<br />
interruptions.<br />
Full mobility<br />
Provide up to 120 km/hr mobility service <strong>wi</strong>th less than 50 ms latency <strong>and</strong> less than 1%<br />
packet loss.<br />
4.3.1. IEEE 802.16-2004<br />
4.3.1.1. Physical Layer<br />
There are several key technologies used in IEEE 802.16-2004 (<strong>fi</strong>xed-WiMax). The <strong>fi</strong>xed-<br />
WiMax is based on OFDM-PHY. It has a strong ability to protect against multipath fading <strong>and</strong><br />
support multipath <strong>and</strong> NLOS transmission. The blueprint <strong>of</strong> the operation theory is derived from<br />
the 802.11a. The 802.16 WG changed some parameters to <strong>fi</strong>t its own dem<strong>and</strong>s. The <strong>fi</strong>gure 4-1<br />
shows the fundamental structure <strong>of</strong> IEEE 802.16 bottom layers.<br />
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