Characteristics of selected wireless link standards
Indoor
10-30m
Outdoor
50-200m
Mid-range outdoor
200m – 4 Km
Long-range outdoor
5Km – 20 Km
.384
.056
200
54
5-11
4
1
IS-95,
CDMA, GSM
2G
UMTS/WC
DMA, CDMA2000
3G
802.15
802.11b
802.11a,g
UMTS/WCDMA-HSPDA, CDMA2000-1xEVDO
3G cellular enhanced
802.16 (WiMAX)
802.11a,g point-to-point
802.11n
Data rate (Mbps)
data
Elements of a wireless network
network infrastructure
infrastructure mode
- base station connects mobiles into wired network
- handoff: mobile changes base station providing connection into wired network
Elements of a wireless network
ad hoc mode
- no base stations
- nodes can only transmit to other nodes within link coverage
- nodes organize themselves into a network: route among themselves
Wireless Networks Taxonomy | |
Infrastructure-based
|
Infrastructure-less
|
Single hop
|
Base station connected
|
No wired network; one
| | |
to larger wired network
|
node coordinates the
| | |
(e.g., WiFi wireless LAN, and cellular
|
transmissions of the others (e.g., Bluetooth,
| | |
telephony networks)
|
and ad hoc 802.11)
|
Multi-hop
|
Base station exists, but
|
No base station exists,
| | |
some nodes must relay
|
and some nodes must
| | |
through other nodes (e.g., wireless sensor
|
relay through others (e.g., mobile ad hoc
| | |
networks, and wireless
|
networks, like vehicular
| | |
mesh networks)
|
ad hoc networks)
| Going Wireless: Widespread Deployment - Worldwide cellular subscribers
- 1993: 34 million
- 2005: more than 2 billion
- 2009: more than 4 billion
- More than landline subscribers
- Wireless LANs
- Wireless adapters built in to most laptops, and even PDAs
- > 286,000 known WiFi locations in > 134 countries
- Probably many, many more (e.g., home networks, corporate networks, …)
http://www.economist.com/daily/chartgallery/displaystory.cfm?story_id=14896700
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