Research shows that you can send and receive on the same channel
You can’t shout and hear the other guy at the same point of time. And if two people in a conversation are both shouting, nobody can make out a thing. No, we are not talking about the nightly verbal mara-mari on some primetime Indian TV news channels.
This is a problem that telecommunications people have lived with for 150 years. The conventional wisdom is: “It is generally not possible for a radio to receive and transmit on the same frequency band, because of the interference.” That is why, on mobile phones or with large communication transceivers, you need two separate frequencies, one to transmit and another to receive.
Last week, the spotlight was on a young Indian researcher in the US, an alumnus of IIT Kanpur and Stanford University, whose work might change decades-old assumptions which say full-duplex or two way radio communications need two channel’s frequencies. Ichalkaranji, Maharashtra — born Dinesh Bharadia, 28, now at MIT, has been named winner of the Marconi Society’s Young Scholar Award 2016, for his work that drastically improves efficiency by sending and receiving on the same channel. How does he do it By cancelling the self-interference — the electrical equivalent of nullifying the sound of your own shout, to make out what the other person is saying. Dinesh sees his work making a difference in India, where mobile cell towers are thinly spread leading to those notorious call drops: “This technology can be used to build cheap and efficient full-duplex relays which can listen to signal from the mobile tower and transmit it at the same time. By deploying these relays, we can save on expensive cellular tower infrastructure.” The challenge is to shrink his hardware till it fits on a mobile phone. Hopefully, full-duplex radio will soon let us talk and listen in a, easier, clearer and cheaper way.
