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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This class is used for UGS or rtPS connections. The sleep <strong>wi</strong>ndows <strong>and</strong> listen <strong>wi</strong>ndows are<br />
all <strong>fi</strong>xed-length <strong>and</strong> cross each other one by one in order. The BS tells the MS the <strong>wi</strong>ndow size<br />
before entering this power-saving mode.<br />
3. Power-saving class type 3<br />
This mode is used for multicast traf<strong>fi</strong>c or MAC management traf<strong>fi</strong>c. Different from other<br />
classes, it has only a single sleep <strong>wi</strong>ndow. Before entering this mode the BS decides the <strong>wi</strong>ndow<br />
size <strong>and</strong> the start time; then noti<strong>fi</strong>es the MS. The power-saving operation is inactive, after the<br />
sleep <strong>wi</strong>ndow has passed.<br />
4.3.2.2.2.2. Idle Mode<br />
Idle mode is also an optional scheme <strong>of</strong> WiMax power management, <strong>and</strong> it can save more<br />
power than sleep mode. With this scheme, several BS’s are assigned to a paging group <strong>and</strong> a MS<br />
can move <strong>wi</strong>thin this area <strong>and</strong> receive broadcast DL transmission from a BS <strong>wi</strong>thout s<strong>wi</strong>tching or<br />
registering to the network. When a MS is in idle mode, it listens to the network periodically for<br />
determining in which paging group it is <strong>and</strong> running the paging group update. MS also noti<strong>fi</strong>es<br />
the network <strong>of</strong> its appearance while running the paging group update. When a BS needs to<br />
connect <strong>wi</strong>th the MS in idle mode, all the BSs in the paging group, where the MS is, have to join<br />
the paging process. Once the MS receives the paging message, it <strong>wi</strong>ll end the idle mode <strong>and</strong> start<br />
to connect to the network.<br />
In idle mode, a MS has two statuses;, MS paging-unavailable interval <strong>and</strong> MS paging-listen<br />
interval. When a MS is in MS paging-unavailable interval, it cannot be paged but can power<br />
down or run other operations not related <strong>wi</strong>th connection <strong>wi</strong>th BS, such as scanning. In the MS<br />
paging-listen interval, the MS listens to the serving BS for broadcast paging message to see<br />
whether it is paged or not. If it is paged, it ends the idle mode <strong>and</strong> if not, it goes into next MS<br />
paging-unavailable interval.<br />
4.4. The future <strong>of</strong> WiMax<br />
The new member <strong>of</strong> 802.11, 802.11n, is on the way. 3G is also becoming more popular.<br />
Therefore, WiMax de<strong>fi</strong>nitely has to cooperate <strong>wi</strong>th them on a some certain level. WiMax is a<br />
<strong>wi</strong>de range <strong>wi</strong>reless communication; Wi-Fi is short range <strong>and</strong> 3G is also <strong>wi</strong>de range but <strong>wi</strong>th<br />
narrower b<strong>and</strong><strong>wi</strong>dth. Figure 4-7[54] Since they are all <strong>wi</strong>reless communication type systems, the<br />
market <strong>wi</strong>ll be overlapped partially. The services dem<strong>and</strong>ed most from end users are e-mail,<br />
sharing <strong>fi</strong>les, video <strong>and</strong>/or audio transmission <strong>and</strong> etc…. [54]<br />
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