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03/14/2011

The 3rd Generation (3G) of cellular networks have as goal to offer service's datas with high taxes of transmission. The initial objectives established by IMT-2000 (UIT) were 2 Mbit/s in "indoor" environment and low mobility.

The following table presents both standards to 3G networks.

	UMTS	CDMA 2000
Radio Interface	WCDMA	EV-DO
Band per carrier	5 MHz	1.25 MHz
Evolution of the operators that use it	GSM	CDMA
Agency that defines the standardization	3GPP	3GPP2

It's following below both standards (details). To consult technologies 1G, 2G and 2,5G of cellular click here (in portuguese).

UMTS (WCDMA)

The Universal Mobile telecommunications System (UMTS) is used to assign the standard of 3rd generation established to the networks of cellular operators as evolution to GSM operators and use as radio interface: Wideband CDMA (WCDMA) and its evolutions.

-	WCDMA	HSDPA	HSUPA	HSPA	HSPA+	LTE	LTE-A
Specification (Releases)	Rel-99	Rel-5	Rel-6	Rel-7 and 8	Rel-7 and 8	Rel-8 and 9	Rel-10
Taxable datas Max. possible (Dw/Up)*	384/384 (Kbit/s)	7,200/384 (Kbit/s)	7.2/5.8 (Mbit/s)	40/10 (Mbit/s)	42/11.5 (Mbit/s)	100/50 (Mbit/s)	1/0.5 (Gbit/s)
Spec. Published	Mar/00	Mar/02	Mar/05	-	Mar/09	Mar/10	-
Begins the Commercial Operation	Dec/02	Dec/05	-	-	Jun/09	Dec/09	-

* Up: Up Link (ERB->Cellular); Dw: Down Link (Cellular->ERB)

4G Technology 4G: LTE Advanced

ITU established the especifications for a technology to be called as 4G. A determined technology is considered 4G when its is recognized as an IMT-Advanced(4G) system.

In October/2009, LTE-Advanced was evaluated as a candidate to 4G, and in October/2010 ITU announced officially LTE-Advanced as an IMT-Advanced(4G) system.

High Speed Downlink Packet Access (HSDPA) is a service of datas packets, based on WCDMA, that optimizes the transmission of datas in the direction of cellular telephony ( Dw ). High Speed Uplink Packet Access ( HSUPA) will do Dw. With HSPA will be possible to use the channels of HSUPA to VoIP.

Time of latency

Beyond tax data many releases will try to improve the time of latency, time in which the answer of data takes a while to come back. The following table presents a comparison of latency times to many technologies. (Source: UMTS Forum)

milliseconds	GPRS	EDGE*	WCDMA	HSDPA	HSUPA
Latency	700	300	200	130	100

* Rel 4

WCDMA and HSDPA available are based on Frequency Division Duplex (FDD), where two different bands are used to transmission and reception. The specifications of 3GPP also include a version with Time Division Duplex (TDD) where the trasmission and the reception use the same frequency band of alternating form. A part of TDD is the Time Division-Synchronous CDMA ( TD-SCDMA) developed to be used in China.

The next step to the HSPA previous by 3GPP is a project called Long Term Evolution (LTE) based in Orthogonal Frequency Division Multiplex Access (OFDMA) and has as objective taxes datas of 100 Mbit/s in the down link with a band of 20 MHz.

The release 5 and the following also define IP Multimedia Subsystem (IMS) plataform of services to multimedia application implemented in the "core" IP of the network to provide uniform services for more different standards of radio interface.

Consult Teleco's tutorials: UMTS, HSDPA.

Frequencies

Most part of WCDMA systems are being implemented in the bands of 1920-1980MHz/2110-2170 MHz allocated by UIT to 3G. Also there are implantations in the bands 850 MHz and 1900 MHz. Some vendors also developed WCDMA to the band 900 MHz

Sites with UMTS informations

3GPP	Responsible by UMTS standardization
ETSI	Developed the norms to GSM. It's possible to download the norms without payment.
GSM World	Site of the GSM world association. GSM statistics in the World.
3Gamericas	GSM association site in the Americas. Technical and Statistics information of the technologies.
UMTS	UMTS Forum. Informations about UMTS and WCDMA system.
GSA	Site of the Global Mobile Suppliers Association. Statistics of 3G in the world.
3GToday	Site with information about 3G systems

CDMA 2000 (EV-DO)

The following table presents the evolution of EV-DO through many revisions of it specification.

	EV-DO
Specification (Revisions)	Rev 0	Rev A	Rev B
Tax datas Max. possible (Dw/Up)*	2,400/153 (Kbit/s)	3.1/1.8 (Mbit/s)	73/27 ** (Mbit/s)
Average of Tax datas (real)	400 a 700 (Kbit/s)	-	-
Begins the Commercial Operation	2002	Oct/06	-

* Up: Up Link (ERB->Celular); Dw: Down Link (Celular->ERB)

** Theoretician Tax using 15 carriers (20 MHz)

In the 1x EV-DO (Rev 0) is used just 1,25 MHz for datas. Since the Rev. A this carrier can be also used to VOIP. The Revision B allows the joint of many carriers (1 till 15).

3GPP2	Responsible for the standardization of CDMA 2000.
TIA	Developed the norms to CDMA.
3GToday	Site with informations about 3G systems.
CDG	CDMA Development Group, international trust of companies that give suport to CDMA.