Scientists shatter limit on over-the-air

Scott Cronk n7fsp@linux.n7fsp.ampr.org
Tue, 13 Oct 1998 04:46:51 -0700 (PDT)


 Scientists shatter limit on over-the-air
 transmissions

 Lucent Technologies has developed a fundamentally
 new technology that the company claims can boost
 the capacity of fixed wireless links by as much as
 10 to 20 times, without increasing the bandwidth.
 Its called BLAST, and Newslines David Black, KB4KCH
 tells us that BLAST may even be applicable to ham
 radio use.

 Sometimes taking another look at what is already
 understood can be valuable.  That's what the Murray
 Hill, New Jersey, technology company did and BLAST
 was born by revisiting a 50 year old mathematical
 theory.

 According to Lucent, the central idea behind BLAST
 is to exploit, rather than mitigate, multipath
 effects.  Lucent says that helps achieve very high
 bandwidth efficiency a lot higher when you treat
 multipath as an ally instead of an adversary.

 Researchers say it's possible to have several
 transmissions occupying the same frequency with
 each transmission having its own, essentially
 co-located, transmitting antenna.  At the receiving
 end, multiple antennas are again used and there's
 a special computerized signal processing algorithm
 in use.

 The algorithm separates the mutually interfering
 transmissions from each other.  As a result, Lucent
 says the capacity of a given frequency band
 increases proportionally to the number of antennas.

 BLAST may be several years away from being
 available and even longer in amateur radio.  Still,
 it could mean increased efficiency in packet radio
 backbone links and intertied digital voice repeater
 circuits.   BLAST may also encourage
 experimentation in completely new modes of amateur
 radio communications.  The benefits could include
 greater throughput for emergency, health and
 welfare and public service communications.

 If you'd like more information about BLAST, you can
 find it at the Lucent Bell Lab's website.  That
 address is in the printed version of this week's
 Newsline report.

 From Birmingham, Alabama, David Black, KB4KCH, for
 Newsline.


 A BLAST prototype has been built to test the theory.
 The device uses an array of eight transmitting and
 twelve receiving antennas.  During its first weeks
 of operation, it achieved unprecedented wireless
 capacity of over ten times the capacity of today's
 competing systems.

 To read more about this remarkable technology, see:

      http://www.bell-labs.com/projects/blast/

 and

 http://www.bell-labs.com/news/1998/september/9/1.html

 (Via CGC Communicator and Lucent Technology Website)