ayomm86
2012-06-03, 03:50 PM
3G is a short term for third-generation wireless, and refers to near-future developments in personal and business wireless technology, especially mobile communications. This phase is expected to reach maturity between the years 2003 and 2005. The third generation, as its name suggests, follows the first generation (1G) and second generation (2G) in wireless communications. The 1G period began in the late 1970s and lasted through the 1980s. These systems featured the first true mobile phone systems, known at first as "cellular mobile radio telephone." These networks used analogue voice signalling, and were little more sophisticated than repeater networks used by amateur radio operators. The 2G phase began in the 1990s, and much of this technology is still in use. The 2G cell phone features digital voice encoding. Examples include CDMA, TDMA, and GSM. Since its inception, 2G technology has steadily improved, with increased bandwidth, packet routing, and the introduction of multimedia. The present state of mobile wireless communications is often called 2.5G. Ultimately, 3G is expected to include capabilities and features such as: · Enhanced multimedia (voice, data, video, and remote control) · Usability on all popular modes (cellular telephone, e-mail, paging, fax, videoconferencing, and Web browsing) · Broad bandwidth and high speed (upwards of 2 Mbps) · Routing flexibility (repeater, satellite, LAN) · Operation at approximately 2 GHz transmit and receive frequencies · Roaming capability throughout Europe, Japan, and North America While 3G is generally considered applicable mainly to mobile broadband deals, it is also relevant to fixed wireless and portable wireless. The ultimate 3G system might be operational from any location on, or over, the earth's surface, including use in or by: · Homes · Businesses · Government offices · Medical establishments · The military · Personal and commercial land vehicles · Private and commercial watercraft and marine craft · Private and commercial aircraft (except where passenger use restrictions apply) · Portable (pedestrians, hikers, cyclists, campers) · Space stations and spacecraft Proponents of 3G technology promise that it will "keep people connected at all times and in all places." Researchers, engineers, and marketeers are faced with the challenge of accurately predicting how much technology consumers will actually be willing to pay for. (Recent trends suggest that people sometimes prefer to be disconnected, especially when on vacation.) Another concern involves privacy and security issues. As technology becomes more sophisticated and bandwidth increases, systems become increasingly vulnerable to attack by malicious ****ers (known as *****ers) unless countermeasures are implemented to protect against such activity. Cdma2000 and UMTS were developed separately and are 2 separate ITU approved 3G standards. Cdma2000 1xRTT, cdma2000 1xEV-DO (EVolution, Data Only) and future cdma2000 3x were developed to be backward compatible with cdmaOne. Both 1x types have the same bandwidth, chip rate and it can be used in any existing cdmaOne frequency band and network. Backward compatibility was a requirement for successful deployment for USA market. It is easy to implement because operators do not need new frequencies. UMTS was developed mainly for countries with GSM networks, because these countries have agreed to free new frequency ranges for UMTS networks. Because it is a new technology and in a new frequency band, whole new radio access network has to be build. The advantage is that new frequency range gives plenty of new capacity for operators.