Mobile Technology General Info

2G

2G (or 2-G) is short for second-generation wireless telephone technology. Second generation 2G cellular telecom networks were commercially launched on the GSM standard in Finland by Radiolinja (now part of Elisa Oyj) in 1991.[1] Three primary benefits of 2G networks over their predecessors were that phone conversations were digitally encrypted; 2G systems were significantly more efficient on the spectrum allowing for far greater mobile phone penetration levels; and 2G introduced data services for mobile, starting with SMS text messages.

2G technologies can be divided into TDMA-based and CDMA-based standards depending on the type of multiplexing used. The main 2G standards are:

• GSM (TDMA-based), originally from Europe but used in almost all countries on all six inhabited continents. Today accounts for over 80% of all subscribers around the world. Over 60 GSM operators are also using CDMA2000 in the 450 MHz frequency band (CDMA450)

• IS-95 aka cdmaOne (CDMA-based, commonly referred as simply CDMA in the US), used in the Americas and parts of Asia. Today accounts for about 17% of all subscribers globally. Over a dozen CDMA operators have migrated to GSM including operators in Mexico, India, Australia and South Korea.

• PDC (TDMA-based), used exclusively in Japan

• iDEN (TDMA-based), proprietary network used by Nextel in the United States and Telus Mobility in Canada

• IS-136 a.k.a. D-AMPS (TDMA-based, commonly referred as simply 'TDMA' in the US), was once prevalent in the Americas but most have migrated to GSM.

2G services are frequently referred as Personal Communications Service, or PCS, in the United States.

GSM frequency usage around the world

Quad-band

The term quad-band describes a device that supports four frequency bands: 850 and 1900 MHz, mostly used in Canada and the United States, and the common 900 and 1800 MHz bands.

System	Band	Uplink (MHz)	Downlink (MHz)	Channel number
GSM-850	850	824.2–849.2	869.2–894.2	128–251
P-GSM-900	900	890.0–915.0	935.0–960.0	1–124
E-GSM-900	900	880.0–915.0	925.0–960.0	975–1023, 0-124
R-GSM-900	900	876.0–915.0	921.0–960.0	955–1023, 0-124
T-GSM-900	900	870.4–876.0	915.4–921.0	dynamic
DCS-1800	1800	1,710.2–1,784.8	1,805.2–1,879.8	512–885
PCS-1900	1900	1,850.2–1,909.8	1,930.2–1,989.8	512–810

The Americas

In North America, GSM operates on the primary mobile communication bands 850 MHz and 1,900 MHz. In Canada, GSM-1900 is the primary band used in urban areas with 850 as a backup, and GSM-850 being the primary rural band. In the United States, regulatory requirements determine which area can use which band.

GSM-1900 and GSM-850 are also used in most of South and Central America, and both Ecuador and Panama use GSM-850 exclusively (Note: Since November 2008, a Panamanian operator has begun to offer GSM-1900 service). Venezuela and Brazil use GSM-850 and GSM-900/1800 mixing the European and American bands. Some countries in the Americas use GSM-900 or GSM-1800, some others use three: GSM-850/900/1900, GSM-850/1800/1900, GSM-900/1800/1900 or GSM-850/900/1800. Soon some countries will use GSM-850/900/1800/1900 MHz like the Dominican Republic, Trinidad & Tobago and Venezuela.

In Brazil, the 1,900 MHz band is paired with 2,100 MHz to form the IMT-compliant 2,100 MHz band for 3G services. The result is a mixture of usage in the Americas that requires travelers to confirm that the phones they have are compatible with the band of the networks at their destinations. Frequency compatibility problems can be avoided through the use of multi-band (tri-band or, especially, quad-band) phones.

Africa, Europe, Middle East and Asia

In Africa, Europe, Middle East and Asia, most of the providers use 900 MHz and 1800 MHz bands. GSM-900 is most widely used. Fewer operators use DCS-1800 and GSM-1800. A dual-band 900/1800 phone is required to be compatible with almost all operators. At least the GSM-900 band must be supported in order to be compatible with many operators. However, Thailand has also approved for some time now the use of the GSM-1900 band in an attempt to alleviate network congestion.

2.5G (GPRS)

2.5G ("second and a half generation") is used to describe 2G-systems that have implemented a packet-switched domain in addition to the circuit-switched domain. It does not necessarily provide faster services because bundling of timeslots is used for circuit-switched data services (HSCSD) as well. The first major step in the evolution of GSM networks to 3G occurred with the introduction of General Packet Radio Service (GPRS). CDMA2000 networks similarly evolved through the introduction of 1xRTT. The combination of these capabilities came to be known as 2.5G. GPRS could provide data rates from 56 kbit/s up to 115 kbit/s. It can be used for services such as Wireless Application Protocol (WAP) access, Multimedia Messaging Service (MMS), and for Internet communication services such as email and World Wide Web access. GPRS data transfer is typically charged per megabyte of traffic transferred, while data communication via traditional circuit switching is billed per minute of connection time, independent of whether the user actually is utilizing the capacity or is in an idle state. 1xRTT supports bi-directional (up and downlink) peak data rates up to 153.6 kbit/s, delivering an average user data throughput of 80-100 kbit/s in commercial networks.[3] It can also be used for WAP, SMS & MMS services, as well as Internet access.

2.75G (EDGE)

GPRS1 networks evolved to EDGE networks with the introduction of 8PSK encoding. Enhanced Data rates for GSM Evolution (EDGE), Enhanced GPRS (EGPRS), or IMT Single Carrier (IMT-SC) is a backward-compatible digital mobile phone technology that allows improved data transmission rates, as an extension on top of standard GSM. EDGE was deployed on GSM networks beginning in 2003—initially by Cingular (now AT&T) in the United States.

EDGE is standardized by 3GPP as part of the GSM family and it is an upgrade that provides a potential three-fold increase in capacity of GSM/GPRS networks.

3G

3G, short for 3rd Generation, is a term used to represent the 3rd generation of mobile telecommunications technology. This is a set of standards used for mobile devices and mobile telecommunication services and networks that comply with the International Mobile Telecommunications-2000 (IMT-2000) specifications by the International Telecommunication Union.[1] 3G finds application in wireless voice telephony, mobile Internet access, Fixed Wireless Internet access, video calls and mobile TV.

Several telecommunications companies market wireless mobile Internet services as 3G, indicating that the advertised service is provided over a 3G wireless network. Services advertised as 3G are required to meet IMT-2000 technical standards, including standards for reliability and speed (data transfer rates). To meet the IMT-2000 standards, a system is required to provide peak data rates of at least 200 kbit/s (about 0.2 Mbit/s). However, many services advertised as 3G provide higher speed than the minimum technical requirements for a 3G service. Recent 3G releases, often denoted 3.5G and 3.75G, also provide mobile broadband access of several Mbit/s to smartphones and mobile modems in laptop computers.

The following common standards comply with the IMT2000/3G standard:

• EDGE, a revision by the 3GPP organization to the older 2G GSM based transmission methods, utilizing the same switching nodes, base station sites and frequencies as GPRS, but new base station and cellphone RF circuits. It is based on the three times as efficient 8PSK modulation scheme as supplement to the original GMSK modulation scheme. EDGE is still used extensively due to its ease of upgrade from existing 2G GSM infrastructure and cell-phones.

• • EDGE combined with the GPRS 2.5G technology is called EGPRS, and allows peak data rates in the order of 200 kbit/s, just as the original UMTS WCDMA versions, and thus formally fulfills the IMT2000 requirements on 3G systems. However, in practice EDGE is seldom marketed as a 3G system, but a 2.9G system. EDGE shows slightly better system spectral efficiency than the original UMTS and CDMA2000 systems, but it is difficult to reach much higher peak data rates due to the limited GSM spectral bandwidth of 200 kHz, and it is thus a dead end.

• • Evolved EDGE, the latest revision, has peaks of 1 Mbit/s downstream and 400kbit/s upstream, but is not commercially used.

• UMTS - The Universal Mobile Telecommunications System, created and revised by the 3GPP. The family is a full revision from GSM in terms of encoding methods and hardware, although some GSM sites can be retrofitted to broadcast in the UMTS/W-CDMA format.

• • W-CDMA is the most common deployment, commonly operated on the 2,100 MHz band. A few others use the 850, 900 and 1,900 MHz bands.

• The CDMA2000 system, or IS-2000, including CDMA2000 1x and CDMA2000 High Rate Packet Data (or EVDO), standardized by 3GPP2 (differing from the 3GPP), evolving from the original IS-95 CDMA system, is used especially in North America, China, India, Japan, South Korea, Southeast Asia, Europe and Africa

UMTS frequency bands

The UMTS frequency bands are radio frequencies used by third generation (3G) wireless Universal Mobile Telecommunications System networks.

Deployments by region

In general, the various UMTS bands are deployed as follows:

• Band I (W-CDMA 2100) in Europe, India, Africa, Israel, Asia, Australia (all carriers' metropolitan networks), New Zealand (ITU Region 1), Thailand (TOT (Thailand)), and Brazil (part of ITU Region 2)
• Band II (W-CDMA 1900) in North America and South America (ITU Region 2).
• Band IV (W-CDMA 1700 or Advanced Wireless Services) in the United States (T-Mobile USA), Canada (WIND Mobile, Mobilicity, Vidéotron) and Chile (VTR Movil, Nextel Chile)
• Band V (W-CDMA 850) in Australia (NextG|Telstra NextG, Vodafone Hutchison Australia Vodafone), Hong Kong (SmarTone), Thailand (True move and DTAC), New Zealand (XT Mobile Network), Brazil, Canada, the USA, Guatemala, Costa Rica, Dominican Republic (Claro),Venezuela, other parts of South America, Israel (Pelephone, , parts of Asia (ITU Region 2 and ITU Region 3), Poland (Sferia)
• Band VIII (W-CDMA 900) in Europe, Asia, Australia (Optus and Vodafone regional/country 3G networks), New Zealand (Vodafone NZ), Thailand (Advanced Info Service), Dominican Republic (Orange Dominicana), Venezuela (Digitel GSM), Poland (Play (telecommunications) and Aero2 HSPA+ Internet only)

For more info see Wikipedia [1]