 By exploiting the structure of the interfering signals, multiuser detection can increase spectral efficiency, receiver sensitivity, and the number of users the system can sustain.Because of the mistaken belief in some quarters of the spread spectrum community that little could be gained from receivers more sophisticated than the single-user matched filter, multiuser detection did not start developing until the early 1980s.Verdu showed that the near-far problem suffered by CDMA was not inherent to this multiplexing technology and could be overcome by an optimum receiver that demodulates all users simultaneously.