In a wireless network with many users, it is known that dirty paper coding
achieves the sum-rate capacity in the downlink. But this requires the base-station
to be fully informed about the channel states of all the active users in the network.
Thus the amount of feedback from the mobiles to the bases station is large.

 In this reseach we are interested in schemes that exploit the mutiusers diversity gain
and only require a low bit-rate feedback from the mobiles to the bases station.

When both the bases station and the mobiles are equiped with only one antenna, then
the best transmit strategy in downlink is to transmit to the user with the highest channel
gain. This requires that all the users report their channel gain to the base station.
We have proved that even if the feedback rate is reduced to one bit per user, still most
of the mutiuser diversity advantage can be obtained provided that the quantization
threshold is chosen judiciously by the base-station.