Adaptive modulation and coding is a technique that controls modulation order and channel coding rate with respect to the feedback channel quality information. If the channel quality information is good, the high order modulation and high rate channel coding will be used. The channel quality information of user $ k $ is given by $ \mathrm{CQI}_k = P_k/N_k $ where $ P_k, N_k $ are the signal and noise power of user $ k $ estimated at the receive side.