The efficient utilisation of bandwidth (or the spectgraf efficiency) has always been a major problem in mobile communication, which is measured in terms of bits per second per Hz of bandwidth. At the same time, one would like to have a certain fidelity at these small power levels even when the channel is noisy, which is given in terms of BER, Bit Error Rate.
As we know, both power as well as bandwidth are a scarce commodity in mobile communication, and therefore it is very important to find out ways and means so that errors that occur in the channels can be corrected.