3G

"G" History

   The first generation (1G) began in the early 1980's with the commercial deployment of Advanced Mobile Phone Service (AMPS) cellular networks. Early AMPS networks used Frequency Division Multiplexing Access (FDMA) to carry analog voice over channels in the 800 MHz frequency band.

    The second generation (2G) emerged in the 1990's when mobile operators deployed two competing digital voice standards. In North America, some operators adopted IS-95, which used Code Division Multiple Access (CDMA) to multiplex up to 64 calls per channel in the 800 MHz band. Across the world, many operators adopted the Global System for Mobile communication (GSM) standard, which used Time Division Multiple Access (TDMA) to multiplex up to 8 calls per channel in the 900 and 1800 MHz bands.

     To get from 2G to 3G, mobile operators had make evolutionary upgrades to existing networks while simultaneously planning their new mobile broadband networks. This lead to the establishment of two distinct 3G families: 3GPP and 3GPP2.

   The 3rd Generation Partnership Project (3GPP) was formed in 1998 to foster deployment of 3G networks that descended from GSM. 3GPP technologies evolved as follows.



• General Packet Radio Service (GPRS) offered speeds up to 114 Kbps.


• Enhanced Data Rates for Global Evolution (EDGE) reached up to 384 Kbps.


• UMTS Wideband CDMA (WCDMA) offered downlink speeds up to 1.92 Mbps.


• High Speed Downlink Packet Access (HSDPA) boosted the downlink to 14Mbps.


• LTE Evolved UMTS Terrestrial Radio Access (E-UTRA) is aiming for 100 Mbps.



GPRS deployments began in 2000, followed by EDGE in 2003. While these technologies are defined by IMT-2000, they are sometimes called "2.5G" because they did not offer multi-megabit data rates. EDGE has now been superceded by HSDPA (and its uplink partner HSUPA). According to the 3GPP, there were 166 HSDPA networks in 75 countries at the end of 2007. The next step for GSM operators: LTE E-UTRA, based on specifications completed in late 2008.



A second organization – the 3rd Generation Partnership Project 2 (3GPP2) -- was formed to help North American and Asian operators using CDMA2000 transition to 3G. 3GPP2 technologies evolved as follows.

• One Times Radio Transmission Technology (1xRTT) offered speeds up

   to 144 Kbps.

• Evolution – Data Optimized (EV-DO) increased downlink speeds up to

   2.4 Mbps.

• EV-DO Rev. A boosted downlink peak speed to 3.1 Mbps and reduced

   latency.

• EV-DO Rev. B can use 2 to 15 channels, with each downlink peaking

   at 4.9 Mbps.

• Ultra Mobile Broadband (UMB) was slated to reach 288 Mbps on the

   downlink.

   In fact, LTE and UMB are often called 4G (fourth generation) technologies because they increase downlink speeds an order of magnitude. This label is a bit premature because what constitutes "4G" has not yet been standardized. The ITU is currently considering candidate technologies for inclusion in the 4G IMT-Advanced standard, including LTE, UMB, and WiMAX II. Goals for 4G include data rates of least 100 Mbps, use of OFDMA transmission, and packet-switched delivery of IP-based voice, data, and streaming multimedia.