Wireless Network Technology: Difference between revisions
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==WiMax== | ==WiMax== | ||
1. WiMax MAC is very similar to bluetooth - there is a master/slave, AP/client relationship and the MAC layer creates dedicated time slots for clients which can enlarge and constrict. Very different to the contention based CSMA/CA model in WiFi which causes the typical collision and unfairness problems. | 1. WiMax MAC is very similar to bluetooth - there is a master/slave, AP/client relationship and the MAC layer creates dedicated time slots for clients which can enlarge and constrict. Very different to the contention based CSMA/CA model in WiFi which causes the typical collision and unfairness problems. | ||
2. Working group in progress for mesh standard for WiMax. If they keep the master/client relationship with central arbitration ... mesh becomes tricky - I've seen the complexity with Bluetooth scatternets where you have to have multiple time sync points - I wonder if they will keep to the same MAC scheme for mesh. Searched all IEEE papers - no one has let this cat out of the bag | 2. Working group in progress for mesh standard for WiMax. If they keep the master/client relationship with central arbitration ... mesh becomes tricky - I've seen the complexity with Bluetooth scatternets where you have to have multiple time sync points - I wonder if they will keep to the same MAC scheme for mesh. Searched all IEEE papers - no one has let this cat out of the bag | ||
3. WiMax is is mainly defined at the MAC layer, it can run on many different PHY layers although OFDM seems to be the favoured choice at the moment. | 3. WiMax is is mainly defined at the MAC layer, it can run on many different PHY layers although OFDM seems to be the favoured choice at the moment. | ||
4. There are two frequency bands being defined for WiMax 10 to 66GHz and 802.16a added support for 2 to 11GHz in the unlicensed frequency bands. | 4. There are two frequency bands being defined for WiMax 10 to 66GHz and 802.16a added support for 2 to 11GHz in the unlicensed frequency bands. | ||
5. Claim distances of 50km but real world tests haven't gone beyond 5 to 8 km | 5. Claim distances of 50km but real world tests haven't gone beyond 5 to 8 km | ||
6. Claim data rates of up to 70 Mbit/s but real world tests show data rates between 500kbit/s and 2 Mbit/s | 6. Claim data rates of up to 70 Mbit/s but real world tests show data rates between 500kbit/s and 2 Mbit/s | ||
Revision as of 15:41, 17 November 2005
Wirless PAN
PAN or Personal Area Network describes connectivity of devices in the immediate space of the user. For example, the enablement of communication between a handheld device like a cellular phone and a nearby pc.
Bluetooth
UWB
Wireless LAN
LAN or Local Area Network, for example, an office area.
Wifi
IEEE 802.11
Wireless MAN
MAN or Metropolitan Area Network describes networks large enough to service a city.
WiMax
1. WiMax MAC is very similar to bluetooth - there is a master/slave, AP/client relationship and the MAC layer creates dedicated time slots for clients which can enlarge and constrict. Very different to the contention based CSMA/CA model in WiFi which causes the typical collision and unfairness problems.
2. Working group in progress for mesh standard for WiMax. If they keep the master/client relationship with central arbitration ... mesh becomes tricky - I've seen the complexity with Bluetooth scatternets where you have to have multiple time sync points - I wonder if they will keep to the same MAC scheme for mesh. Searched all IEEE papers - no one has let this cat out of the bag
3. WiMax is is mainly defined at the MAC layer, it can run on many different PHY layers although OFDM seems to be the favoured choice at the moment.
4. There are two frequency bands being defined for WiMax 10 to 66GHz and 802.16a added support for 2 to 11GHz in the unlicensed frequency bands.
5. Claim distances of 50km but real world tests haven't gone beyond 5 to 8 km
6. Claim data rates of up to 70 Mbit/s but real world tests show data rates between 500kbit/s and 2 Mbit/s
WiBro
Wireless WAN
WAN or Wide Area Network describes large networks that typically cover areas as large as an entire country.
2.5G
GPRS
General Packet Radio System
EDGE
HSDPA
3G
CDMA
CDMA - Code Division Multiple Access
CDMA-2000
W-CDMA
4G
4G is a network of networks, it is a solution looking for a problem. Terminal has to accommodate converged radio networks. “The user wants to google cnn anytime, anywhere at the right cost having all security considered…” (IWS2005, summary of exec round table discussion on 4G).
Also described as an IP Ubiquitous Network.