Cellular Interference Alignment with Imperfect Channel Knowledge

Interference alignment is evaluated as a technique to mitigate inter-cell interference in the downlink of a cellular network using OFDMA. The sum mutual information achieved by interference alignment together with a zero-forcing receiver is considered, and upper and lower bounds are derived for the case of imperfect channel knowledge. The sum mutual information achieved by interference alignment when the base stations share their information about the channels is shown to compare favorably to the achievable sum-rate of methods where the base stations do not cooperate, even under moderately accurate knowledge of the channel state.