Query regarding GSM frequencies,.???

[gmkumar08]

Today, i had my project external and have been asked a few questions. I answered them but am not sure about them. The questions are -

It is known that GSM works in the frequency range 800/900 MHz. Now does that mean the tower transmits at 800 MHz and the mobile receives the same and while calling does the mobile transmits at 800 MHz and the tower receives the same. Also, when we are moving, and hand off takes place, does one tower communicates with the neighbouring tower for this hand off action. If yes, then does it also communicates in the same frequency of 800 MHz.

Can someone explain these to me,.please,.thanks a lot,..

 

[betwixt]

As far as I know, hand-off is done by landline.
GSM also uses 1710MHz to 1880 MHz. Both are time division multiplexed. One transmitter in each cell sends a signal to allocate a time slot for all the handsets in range and each handset uses only it's allocated slot to 'talk' to the cell base station. That way, several handsets can share the same frequency without interfering with each other.

Brian.