1. Wireless LANs
B 第七組 彭宇正
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2. Outline What is Wireless LAN Topology Wireless LAN Standards
Comparison
Conclusion
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3. Outline What is Wireless LAN Topology Wireless LAN Standards
Comparison
Conclusion
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4. What is Wireless LAN
A wireless LAN or WLAN is a wireless local area network that uses radio waves as its carrier.
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5. Outline What is Wireless LAN Topology Wireless LAN Standards
Comparison
Conclusion
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6. Topology Infrastructure network BSS AP BSS : Basic Service Set
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7. Topology
Infrastructure network
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8. Topology
ad hoc network
BSS
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9. Topology
ad hoc network
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10. Outline What is Wireless LAN Topology Wireless LAN Standards
Comparison
Conclusion
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11. Wireless LAN Standards
Freq.
Data Rate
Distance
Modulation Scheme
IEEE a (Wi-Fi)
5 GHz
54 Mbps
30m
OFDM
IEEE b (Wi-Fi)
2.4 GHz
11 Mbps
100m (indoor)
400m (outdoor)
DSSS with CKK
IEEE g (Wi-Fi)
20Mbps↑:OFDM
20Mbps↓:DSSS
IEEE
(WiMAX)
2 ~11 GHz
70 Mbps
4~6 miles
(<30 miles)
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12. Wireless LAN Standards
Freq.
Data Rate
Distance
Modulation Scheme
Bluetooth
2.45 GHz
1 Mbps
0.1 ~ 100m
FHSS
HomeRF
2.4 GHz
10 Mbps
50m
IrDA
(850~900nm IR LED )
4 Mbps
20cm ~ 1m
UWB
3.1 ~ 10.6 GHz
1 Gbps
10 m
OFDM
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13. Outline What is Wireless LAN Topology Wireless LAN Standards
Comparison
Conclusion
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14. Comparison
IEEE a/b/g
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15. Comparison IEEE 802.11a/b/g IEEE 802.11b Lowest cost
Data Rate
Bluetooth
IrDA
HomeRF
IEEE b
IEEE a/g
IEEE
UWB
Slow
Fast
IEEE b
Lowest cost
Signal range is best
Slowest maximum speed (11Mbps)
Fewer simultaneous users
Appliances may interfere on the unregulated frequency band
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16. Comparison IEEE 802.11a/b/g (continued) IEEE 802.11a
Data Rate
Bluetooth
IrDA
HomeRF
IEEE b
IEEE a/g
IEEE
UWB
Slow
Fast
IEEE a
Fastest maximum speed (54Mbps)
More simultaneous users
Prevent signal interference
Highest cost
Signal range is shorter
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17. Comparison IEEE 802.11a/b/g (continued) IEEE 802.11g
Data Rate
Bluetooth
IrDA
HomeRF
IEEE b
IEEE a/g
IEEE
UWB
Slow
Fast
IEEE g
Fastest maximum speed (54Mbps)
More simultaneous users
Signal range is best
Costs more than b
Appliances may interfere on the unregulated signal frequency
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18. Comparison IEEE 802.11a/b/g (continued)
Range
Rate
Cost
Anti-interference
802.11a X O
802.11b
802.11g
IEEE b/g becomes more popular.
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19. Comparison IEEE 802.16 Large signal range (4 ~ 6miles) High speed
Data Rate
Bluetooth
IrDA
HomeRF
IEEE b
IEEE a/g
IEEE
UWB
Slow
Fast
802.11b
802.16
Large signal range (4 ~ 6miles)
High speed
Compatible with IEEE b
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20. Comparison Bluetooth / HomeRF
Data Rate
Bluetooth
IrDA
HomeRF
IEEE b
IEEE a/g
IEEE
UWB
Slow
Fast
Data Rate
Bluetooth
IrDA
HomeRF
IEEE b
IEEE a/g
IEEE
UWB
Slow
Fast
Bluetooth is designed for wireless personal area networks (WPANs).
The HomeRF is designed to carry voice and data within the home.
(ex: SimpleFi …)
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21. Comparison Bluetooth / HomeRF Data Rate Bluetooth Motorola SimpleFi
IrDA
HomeRF
IEEE b
IEEE a/g
IEEE
UWB
Slow
Fast
Motorola SimpleFi
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22. Comparison Bluetooth / HomeRF (continued) Low power (B:30mA)
Data Rate
Bluetooth
IrDA
HomeRF
IEEE b
IEEE a/g
IEEE
UWB
Slow
Fast
Low power (B:30mA)
Low speed (B:1Mbps , H:10Mbps)
Why HomeRF failed?
The standard is not open.
Management.
Intel !!
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23. Comparison IrDA PPP Simple Low power (0.2~0.3mA) Cheap ($2 ~ $3)
Data Rate
Bluetooth
IrDA
HomeRF
IEEE b
IEEE a/g
IEEE
UWB
Slow
Fast
PPP
Simple
Low power (0.2~0.3mA)
Cheap ($2 ~ $3)
Very short signal range
(ex: mobile phone, notebook, PDA)
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24. Comparison IrDA Data Rate Bluetooth Slow IrDA HomeRF IEEE 802.11b
IEEE a/g
IEEE
UWB
Slow
Fast
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25. Comparison UWB Ultra Wideband Extremely high data rate
Bluetooth
IrDA
HomeRF
IEEE b
IEEE a/g
IEEE
UWB
Slow
Fast
Ultra Wideband
Extremely high data rate
Lowest power dissipation
Short signal range
(ex:PC、DVD 、DVR 、digital camera、HDTV 、PDA 、MD、MP3)
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26. Comparison
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27. Comparison
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28. Outline What is Wireless LAN Topology Wireless LAN Standards
Comparison
Conclusion
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29. Conclusion
More and more wireless tech. will be invented in the future.
The data rate will also fast.
Put the right thing in the right place.
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