A practical precoding scheme for multicell MIMO channels with partial user's data sharing

In this work1, we consider a setting where K Transmitters (TXs) equipped with multiple antennas aim at transmitting to their K respective Receivers (RXs) also equipped with multiple antennas. Without exchange of the user's data symbols, this represents a conventional Interference Channel (IC), while it is a so-called MIMO Network Channel if the user's data symbols are fully shared between all the TXs. The focus of this work is on the intermediate case where the user's data symbols can be arbitrary shared to the TXs such that only a subset of the TXs has access to the data symbols to transmit to a given RX. We show that we can build a virtual IC so as so have the transmission in that IC equivalent to the transmission in the original setting. In this virtual IC, it is then possible to apply any of the numerous algorithms (Interference Alignment algorithms) initially tailored for the IC. Finally, we let the routing matrix be optimized subject to a constraint on the total number of symbols shared and use a greedy algorithm to find the user's data allocation. We show by simulations that sharing only few user's data symbols is sufficient to achieve most of the performance.