Adaptive Modulation and Coding for Interference Alignment With Imperfect CSIT

In this paper, interference alignment (IA) based on imperfect channel state information (CSI) is investigated. As the accuracy of the CSI at the transmitter side is crucial for IA, we analyze the statistics of the imperfect CSI and design an adaptive scheme based on the available imperfect CSI. We consider a multiple-input-multiple-output (MIMO) interference channel where the transmit and receive spaces are determined by IA. Using practical modulation schemes, we consider the maximization of a weighted sum of the average rates provided that a certain set of bit-error-rate and power constraints is satisfied by dynamically adapting coding, modulation, and power settings. The problem in such a general form is intractable. Therefore, we resort to some approximations and provide simulations to show the accuracy of the approximations in the regimes with practical interest.