|
Hints and Tips
Navigating
yourself through the wireless maze -
1G analog cellular system : early 1980’s (some still running)
2G digital cellular system : early 1990’s (will operate for next 10
years)
2.5 transition phase
3G latest cellular networks with data rates in access of 384 kbps
3G is a term coined by the global cellular community to indicate the next
generation of mobile service capabilities, e.g. higher capacity and enhanced
network functionalities, which allow advance services and applications,
including multimedia.
4G at research stage – complete global wireless network (about 2010)
IMN 2000 (International Mobile Telecommunications-2000 is global
definition of 3G covering key issues such as frequency spectrum use and
technical standards. WCDMA - Wideband Code Division Multiple Access is the
over-all digital cellular technology standard for 3G.
The aim of these standards is to achieve:
• High transmission data rates for indoor and outdoor operations
• Symmetrical and asymmetrical data transmission
• Circuit-switch and packet-switch services such as IP (Internet Protocol)
traffic and realtime video
• Voice quality comparable to wire-line quality
• Greater capacity and improved spectrum efficiency
• Several simultaneous services to end-users and terminal for multimedia
sevices
• economies of scale through open global standards to meet the needs of the
mass market
• a seamless evolution from 2G through 2.5G to 3G
• all radio access options should work with all network options.
However 3 quite separate, incompatible systems have been developed as
approved 3G networks.
CDMA2000 (Code Division Multiple Access – 2000)
- dominant in North America, Latin America, Asia
UTMS (Universal Mobile Telecommunications System)
- countries with GSM networks – Europe and Asia
TDMA (Time Division Multiple Access)
- China
The problem is being solved with dual/multi phones – eventually phones will
be able to do handovers between networks
Table showing the range of options available
|
|
Purpose |
Freq. |
Range |
Speed |
Devices |
Not Compatible with |
|
Wireless Local Area Networks8022.11 is umbrella term for this family of protocols |
|
|
|
|
|
|
|
802.11a
|
Wireless internet access |
5GHz |
25 – 75 ft indoors |
Up to 54 Mbps |
Laptops PDAs Cell phones |
802.11b/g but can co-exist as there is no signal overlap |
|
80211b Wi-Fi (Wireless Fidelity- trade mark of WECA*) most popular as the 2.4 GHz band is universally available. |
Wireless internet access. Products certified as Wi-Fi are interoperable with each other. |
2.4GHz |
Up to 150 ft indoors |
Up to 11 Mbps |
Laptops PDAs Cell phones |
802.11a |
|
802.11g |
Wireless internet access |
2.4GHz |
Up to 150 ft indoors |
Up to 54 Mbps |
Laptops |
802.11.a |
|
|
|
|
|
|
|
|
Bluetooth |
Wirelessly connect peripherals |
2.4 GHz |
Up to 33 ft |
720 Kbps |
Printers cameras, cell phones etc |
|
|
|
|
|
|
|
|
|
|
GSM (2G) (Global System for Mobile Communications) |
Digital cellular telephone system - standard in Europe |
900 MHz 1,800 MHz 1,900 MHz |
Determined by host network |
Determined by host network |
GSM enabled cell phones, PDAs, pagers |
CDMA TDMA |
|
GPRS (2.5G) (General Packet Radio Service) |
Interface overlaid on existing GSM networks to give always - on Internet connection |
Determined by host network |
Determined by host network |
Theoretically up to 171 Kbps, realistically 40 – 50 Kbps |
GPRS enabled cellular phones and networks |
CDMA |
3 GSMEDGE (Enhanced Data GSM Environment) UMTS |
Third generation GSM network |
1,920 -1,980 MHz 2.110 – 2,170 MHz |
Determined by host network |
2 Mbps data rate |
3GSM enabled cell phones, PDAs, pagers |
CDMA |
|
CDMA (2G, 2.5G) (Code Division Multiple Access) |
Digital telephone system used mainly in US |
800MHz, 900MHz, 1,700MHz, 1,800MHz, 1,900MHz |
Coverage area of host network |
14.4 Kbps 64 Kbps |
Mobile phones on CDMA networks |
GSM TDMA |
CDMA2000 |
Third generation CDMA network |
Any existing band |
Coverage area of host network |
144 Kbps (future estimated at 4.8 Mbps) |
Mobile phones on CDMA2000 networks |
GSM TDMA |
TDMA(Time Division Multiple Access) |
Digital cellular telephone systems |
800 MHz 1,900 MHz |
Coverage area of host network |
64 Kbps – 120 Kbps data rates |
TDMA cellular phones |
GSM CDMA |
OMA (the Open Mobile Alliance was formed in June 2002 as an initiative to
encourage cooperation and information sharing in the communications
industry.
Frequency allocation
CDMA
• new cellular frequencies postponed after 9.11 for 3 years – (radio
spectrum needed by the Pentagon) – backward compatibility
UMTS
• Countries with GSM networks have agreed to free new frequency ranges for
3G - using FDD (Frequency Division Duplex) and later TDD (Time Division
Duplex) – not meant to be backward compatible, but dual phones should make
this possible
*WECA (Wireless Ethernet Compatibility Alliance) certifies the
interoperability of Wi-Fi (IEEE802.11b) and aims to promote it as the global
WLAN standard
IEEE802.11 The Institute of Electrical and Electronic Engineers is
responsible for developing the 802.11 family of specifications for WLAN
(Wireless Local Area Networking)
.