Information Technology Reference
In-Depth Information
The city of Tempe, Arizona implemented a mesh network to provide broadband wireless
access for residents, visitors, students, and mobile workers on their laptop, PDA, or smart-
phone. The network has not been widely accepted—it has 1,000 outdoor access points but
only 500 subscribers.
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3G Wireless Communications
The International Telecommunications Union (ITU) established a single standard for cel-
lular networks in 1999. The goal was to standardize future digital wireless communications
and allow global roaming with a single handset. Called IMT-2000, now referred to as 3G,
this standard provides for faster transmission speeds in the range of 2-4 Mbps. Originally,
3G was supposed to be a single, unified, worldwide standard, but the 3G standards effort
split into several different standards. One standard is the Universal Mobile Telephone System
(UMTS), which is the preferred solution for European countries that use Global System for
Mobile (GSM) communications. GSM is the
de facto
wireless telephone standard in Europe
with more than 120 million users worldwide in 120 countries. Another 3G-based standard
is Code-Division Multiple Access (CDMA), which is used in Australia, Canada, China, India,
Israel, Mexico, South Korea, the United States, and Venezuela. The wide variety of 3G
cellular communications protocols can support many business applications. The challenge
is to enable these protocols to intercommunicate and support fast, reliable, global wireless
communications.
3G wireless communication is useful for business travelers, people on the go, and people
who need to get or stay connected. Although Wi-Fi is an option, 3G is preferable to mobile
users concerned about the availability, cost, and security associated with the use of public
Wi-Fi networks.
4G Wireless Communications
4G stands for fourth-generation broadband mobile wireless, which is expected to deliver
more advanced versions of enhanced multimedia, smooth streaming video, universal access,
portability across all types of devices, and eventually, worldwide roaming capability. 4G will
also provide increased data transmission rates in the 20-40 Mbps range.
Pine Cellular, Pine Telephone, and Choctaw Electric are deploying Nortel 4G technology
to provide homes and businesses in southeastern Oklahoma with reliable, wireless high-speed
Internet. The network will provide low-cost, broad coverage and deliver wireless services to
rural areas where construction of a wired network is less economical. The 4G services will be
provided at no charge to the local police and fire departments and public schools.
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Worldwide Interoperability for Microwave Access (WiMAX)
Worldwide Interoperability for Microwave Access (WiMAX)
is the common name for a
set of IEEE 802.16 wireless metropolitan area network standards that support various types
of communications access. In many respects, WiMAX operates like Wi-Fi, only over greater
distances and at faster transmission speeds. A WiMAX tower connects directly to the Internet
via a high-bandwidth, wired connection. A WiMAX tower can also communicate with an-
other WiMAX tower using a line-of-sight, microwave link. The distance between the
WiMAX tower and an antenna can be as great as 30 miles. WiMAX can support data com-
munications at a rate of 70 Mbps. Fewer WiMAX base stations are required to cover the
same geographical area than when Wi-Fi technology is used. Mobile WiMAX refers to sys-
tems built based on the 802.16e standard and provides both fixed and mobile access over the
same network infrastructure. Fixed WiMAX is based on the 802.16-2004 standard designed
to deliver communications to homes and offices, but it cannot support mobile users. WiMAX
is considered a 4G service.
In mid-2008, Sprint Nextel combined its wireless broadband unit with Clearwire to
create a new communications company whose goal is to build the first national WiMAX
network bringing coverage to 120 million people by the end of 2010. AT&T and Verizon
Wireless have chosen a different direction and plan to upgrade their wireless networks with
chips, and other equipment, Sprint is working with Intel, Motorola, Nokia, and Samsung
Worldwide Interoperability for
Microwave Access (WiMAX)
The common name for a set of IEEE
802.16 wireless metropolitan area
network standards that support dif-
ferent types of communications
access.
