A NEW type of antenna for cellphone handsets could slash the number of base station masts needed for the upcoming 3G mobile phone network. Finding sites for these masts is a major headache for the cellphone networks.
Cellphone base stations usually transmit a large number of signals simultaneously, each one intended for a different phone. So each phone within each cell has to pick out the call destined for it amid the welter of interfering signals. The stronger each individual signal is, the harder this is to do. But make the signals too weak and the antenna won鈥檛 be able to pick them up.
The new antenna, developed by Californian company Innovics Wireless, eases the problem by allowing the cellphone networks to transmit at lower power. It does this by combining the signal it receives directly from the base station with the reflections of the same signal. A conventional cellphone normally only tunes into the strongest signal it can find.
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The smart antenna also uses a trick familiar to car drivers stuck in traffic jams listening to a radio, says Innovics Wireless spokesman Michael Orr. If reception is bad, he says, nudging the car an inch or two forwards can often improve it. Innovics uses the same principle, only you don鈥檛 have to move the handset as it has two antennas built in. This allows the handset to make use of variations in the signal strength over a small distance鈥攊n this case the distance between the antennas.
Commercial trials are due to begin in December. The new antennas could start appearing in 3G handsets as early as next March.