Generations
of mobile communication: 1G, 2G,
3G, 4G, 5G
The
large number of different mobile phone or cell phone systems that are talked
about today can be very confusing. Whilst not all are in use today, some of the
older systems have been superseded and some of the newer systems have not all
been rolled out yet, nevertheless many different names and technologies are
talked about. The table below gives a summary of the main systems that have
been used, are being used or are due for introduction.
Cellphone
System
|
Generation
|
Channel
Spacing
|
Access
Method
|
Comments
|
AMPS
|
1G
|
30
kHz
|
FDMA
|
Advanced
Mobile Phone System, this analogue system first developed and used in the USA
|
NAMPS
|
1G
|
10
kHz
|
FDMA
|
Narrow
band version of AMPS chiefly used in the USA and Israel based on a 10 kHz
channel spacing.
|
TACS
|
1G
|
25
kHz
|
FDMA
|
Analogue
system originally in the UK. Based around 900 MHz, this system spread world wide.
After the system was first introduced, further channels were allocated to
reduce congestion, in a standard known as Extended TACS or ETACS
|
NMT
|
1G
|
12.5
kHz
|
FDMA
|
Nordic
Mobile Telephone. This analogue system was the first system to be widely used
commercially being launched in 1979. It was used initially on 450 MHz and
later at 900 MHz. It was used chiefly in Scandinavia but it was adopted by up
to 30 other countries including Oman.
|
NTT
|
1G
|
25
kHz
|
FDMA
|
Nippon
Telegraph and Telephone. The system used in Japan, using a 900 MHz frequency
band, and 55 MHz transmit receive spacing. (A high capacity version is known
as HICAP).
|
C450
|
1G
|
20
kHz
|
FDMA
|
The
system adopted in West Germany (East Germany was separate at this time). It
used a band in the region of 450 MHz along with a 10 MHz receive / transmit
spacing.
|
GSM
|
2G
|
200
kHz
|
TDMA
|
Originally
called Groupe Speciale Mobile, the initials later stood for Global System for
Mobile communications. It was developed in Europe and first introduced in
1991. The service is normally based around 900 MHz although some 850 MHz
allocations exist in the USA.
|
DCS
1800
|
2G
|
200
kHz
|
TDMA
|
1800
MHz derivation of GSM and is also known as GSM 1800.
|
PCS
1900
|
2G
|
200
kHz
|
TDMA
|
1900
MHz derivation of GSM, and is also known as GSM 1900.
|
TDMA
|
2G
|
30
kHz
|
TDMA
|
Although
it was originally known as US Digital Cellular (USDC) and was introduced in
1991. It is sometimes called North America Digital Cellular and also known by
its standard number IS-54 that was later updated to standard IS136. It is a
2G digital system that was designed to operate alongside the AMPS system.
|
PDC
|
2G
|
25
kHz
|
TDMA
|
Pacific
or Personal Digital Cellular. The system found only in Japan where it has
gained very widespread use. It has many similarities with IS-54 although it uses
a different speech coder and a 25 kHz bandwidth.
|
GPRS
|
2.5G
|
200
kHz
|
TDMA
|
General
Packet Radio Service. A data service that can be layered onto GSM. It uses
packet switching instead of circuit switching to provide the required
performance. Data rates of up to 115 kbps attainable.
|
EDGE
|
2.5
/ 3G
|
200
kHz
|
TDMA
|
Enhanced
Data rates for GSM Evolution. The system uses a different form of modulation
(8PSK) and packet switching which is overlayed on top of GSM to provide the
enhanced performance. Systems using the EDGE system may also be known as
EGPRS systems.
|
CdmaOne
|
2G
|
1.25
MHz
|
CDMA
|
This
is the brand name for the system with the standard reference IS95. It was the
first CDMA system to gain widespread use. The initial specification for the
system was IS95A, but its performance was later upgraded under IS95B which
the cdmaOne specification actually uses. Apart from voice it also carries
data at rates up to 14.4 kbps for IS95A and under IS95B data rates of up to
115 kbps are supported.
|
CDMA2000
1X
|
2.5G
|
1.25
MHz
|
CDMA
|
This
system supports both voice and data capabilities within a standard 1.25 MHz
CDMA channel. CDMA2000 builds on cdmaOne to provide an evolution path to 3G.
The system doubles the voice capacity of cdmaOne systems and also supports
high-speed data services. Peak data rates of 153 kbps are currently
achievable with figures of 307 kbps quoted for the future, and 614 kbps when
two channels are used.
|
CDMA2000
1xEV-DO
|
3G
|
1.25
MHz
|
CDMA
|
The
EV-DO stands for Evolution Data Only. This is an evolution of CDMA 2000 that
is designed for data only use and its specification is IS 856. It provides
peak data rate capability of over 2.45 Mbps on the forward or downlink , i.e.
from the base station to the user. The aim of the system is to deliver a low
cost per megabyte capability along with an always on connection costed on the
data downloaded rather than connection time.
|
CDMA2000
1xEV-DV
|
3G
|
1.25
MHz
|
CDMA
|
This
stands for Evolution Data and Voice. It is an evolution of CDMA2000 that can
simultaneously transmit voice and data. The peak data rate is 3.1 Mbps on the
forward link. The reverse link is very similar to CDMA2000 and is limited to
384 kbps.
|
UMTS
|
3G
|
5
MHz
|
CDMA
/ TDMA
|
Universal
Mobile Telecommunications System. Uses Wideband CDMA (W-CDMA) with one 5 MHz
wide channel for both voice and data, providing data speeds up to 2 Mbps.
|
TD-SCDMA
|
3G
|
1.6
MHz
|
CDMA
|
Time
Division Synchronous CDMA. A system developed in China to establish their
position on the cellular telecommunications arena. It uses the same bands for
transmit and receive, allowing different time slots for base stations and
mobiles to communicate. Unlike other 3G systems it uses only a time division
duplex (TDD) system.
|
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