Monday, August 24, 2009

3G Required


imperative, enabling network engineers to embark on massive 3GTo achieve this level of wireless connectivity over wide areas – a continent or oceans, for example, basic core networks must be interconnected. Cooperation among industry 3G groups has been harmonization efforts to promote IMT-2000 compatibility worldwide. These efforts include developing software and hardware upgrades to core networks that prepare for highbandwidth multimedia services; as well as developing systems to harmonize two different emerging 3G CDMA operating solutions. Both will ultimately talk to each other across the global network space.

The two solutions include W-CDMA (wideband CDMA), a standard that supports fixed network speeds up to 2 MHz, and is endorsed by European standards groups and NTT DoCoMo, the largest wireless carrier in Japan, which has led the first 3G tests and commercial implementations. The second 3G operating solution is CDMA-2000, which is an evolution of the North American IS-95 CDMA standard (also supported under the IMT-2000 3G specification.). Ultimately, both standards will accommodate the high data rates (up to 2 Mbps for fixed apps) specified in IMT- 2000 in both fixed and mobile modes. Figure 3 illustrates the commonly used wireless air interfaces as currently defined in the ITU’s IMT- 2000 Harmonization specification.

The five primary air links have been integrated into the core carrier specification. The five evolved standards are:

1. IMT-DS (W-CDMA direct spread spectrum)
2. IMT-MC (cdma2000 multi-carrier)
3. IMT-TC (TDD-SCDMA time-code division multiplex)
4. IMT-SC (TDMA IS-136 single carrier EDGE)
5. IMT-FT (DECT frequency time division)

In practical terms, the expectation today is that Fixed Wireless Access will become a mainstay of developing countries without adequate wired infrastructure. In developed countries, however, 3G residential wireless represents a new horizon for competitive access providers. The advent of cable modems and DSL has raised the bar substantially for data services, which means that users now readily expect a wireless connection to provide somewhere between 1.5 Mbps and 2 Mbps. In the US, some of the alternative providers are considering broadband, fixed wireless options. But these fixed systems are economical only when shared among small to medium-size businesses, and many have stringent line of sight requirements and suffer from weather-induced impairments. Theresidential and business marketplace is still ripe for a wireless access alternative such as fixed 3G which can be deployed in many different spectrum bands, offers superior in-building penetration, and provides better noise immunity and signal strength than other fixed wireless options.

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