On the degrees of freedom of multiantenna interfering broadcast channels

Abstract

The degrees of freedom (DoF) of multiantenna interfering broadcast channels is studied in which the first base station (BS) with M1 antennas wishes to send independent messages to its N1 serving users and the second BS with M2 antennas wishes to send independent messages to its N2 serving users. Each user is assumed to be equipped with a single antenna. For max(M1, M2) ≤ min(N1, N2), the sum DoF is shown to be upper bounded byThe results characterize the optimal sum DoF if M1N2 = M2N1 and further characterize the asymptotically optimal sum DoF when both N1 and N2 tend to infinity. Specifically, the optimal sum DoF converges to M1 + M2 as N1 and N2 tend to infinity.