Single chip allows multi-mode handsets

Fri, 11 May 2001 08:50:15 "GMT"

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Total Telecom - http://www.totaltele.com

Single chip allows multi-mode handsets

By Elizabeth Biddlecombe, Total Telecom

10 May 2001

http://www.totaltele.com/view.asp?ArticleID=39817&Pub=tt
A Silicon Valley company was last week showing the first ever
multi-mode RF transmitter which it says will enable manufacturers to
develop phones using one chipset for different transmission standards.
The TimeStar chipset  from Tropian supports first, second and 2.5
generation mobile technologies such as AMPS, GSM, TDMA, EDGE and GPRS
so that the one, streamlined and low cost handset can be used to roam
across network types.  This is a Holy Grail for operators who want to
enable customers to use the one handset wherever they are in the
world. "The intention is that the user can roam anywhere in the world
and use a broadband data or a good voice link regardless of what
technology it is", said Alden Lofquist, director of sales for
Cupertino, California-based Tropian.  "Handset manufacturers need to
cover as many different operator standards as possible so that they
can sell to a maximum number of people with a minimum number of
variations in handsets. Once a major manufacturer comes out with a
single radio to transmit multiple modes and frequencies they will have
the price and performance advantage that will force their competitors
top find a similar solution at a similar price."
Tropian claims amongst other things that the multi-mode performance is
as or more efficient than single-mode solutions. TimeStar is enabled
by the use of Polar Impact technology which means that whereas other
systems process the signal in an analogue way, TimeStar processes the
signal in digital form end to end.  "Rather than being a transmitter
that is optimised for each mode, be it voice or data, the various
standards are stored as a digital lookup table in the same way that a
printer changes font", explained Lofquist. 
Tropian has been working on the technology for near on three years,
with an initial task was to prove that the methodology would work. It
now has seven patents for the technology.
The TimeStar transmitter is currently being evaluated by baseboard,
handset, PDA and modem manufacturers while PrairieComm and Infineon
have publicly announced support. Mass production is scheduled for the
beginning of next year. At present only a transmitter is available
though there is a reference design for a receiver. A combined
transceiver will be available on a single chip in a year's time.
Chipsets addressing third generation technologies are not yet
available.