The 10 Hottest Technologies
telecoms-mag.com
"Smart Antennas: Baseline IQ
The move from analog to digital cellular phones improved voice transmission quality and
allowed network operators to offer users more features. The challenge now, as spelled out
by the ITU, is to develop third-generation (3G) wireless systems with sufficient capacity
(up to 384 kbps for mobile applications and up to 2 Mbps for stationary applications) that
would let subscribers make phone calls, surf the Web, exchange e-mail and conduct video
conferences simultaneously. Thus, a need for smart antennas. The move to 3G will require
smart antennas more so than in today?s networks,? said Sandeep Chandel, Nortel Networks
product manager for RF capacity and performance.
Just as the popularity of the Internet is forcing ISPs to increase backbone capacity, the
burgeoning number of wireless phone users is straining the capacity of cell sites. Since
interference is the key threat that limits the capacity of a cell, the simple, albeit
expensive, solution is to add more base stations. In other words, if one base station serves
an area within a 4,000-foot radius, then by splitting that cell into smaller cells through the
addition of more base stations, an operator could reduce the area served by the base station
to a 1000-foot radius. Market research firm Allied Business Intelligence estimates that
wireless subscribers worldwide will number 667 million by the end of 2003. According to
ABI analyst Larry Swasey, operators will deploy 2.5 million base stations by year-end
2003 to keep up with the growing number of subscribers. This is one reason why Texas
Instruments, a leading provider of silicon for handsets, recently started focusing on the
DSP market for base stations.
Conventional base stations waste energy because only a small amount of the signal reaches
the intended recipient. Also, when a base station listens for signals, it not only receives the
desired signal but also interference from other signals. Smart antennas, on the other hand,
are able to listen to a particular subscriber and deliver energy to that subscriber more
efficiently. Martin Cooper, chairman of smart antenna maker ArrayComm and putatively
the father of the cell phone, uses this analogy to explain the concept behind smart
antennas: Even in a crowded room a person is able to filter out irrelevant conversations
and pick up on the voice of a particular individual. ?Similarly, with smart antennas you try
to listen only to people you want to listen to, and you talk back to them,? Cooper said.
?Five years from now any new base station coming into the market will use smart
antennas.?
Companies such as ArrayComm, Metawave and Andrew Corp. hope to either license their
technologies to the established infrastructure vendors or sell their products to network
operators. For instance, Metawave has developed a smart antenna, SpotLight 2000, that
works with both analog and digital systems. It is preparing for a trial of its antenna in
China Telecom?s GSM networks. Metawave claims its antennas result in a 50-percent
boost in capacity in a CDMA system and 100-percent capacity boost in an analog system.
Meanwhile, Ericsson has underway a research and evaluation project of its Wideband
CDMA (WCDMA) system with two GSM network operators in Germany. In contrast to
ETSI, which has specified the CDMA air interface for 3G systems, ANSI will permit any of
the three (CDMA, TDMA and GSM) interfaces.
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