Base Station Cooperatively Scheduled Transmission in a Cellular MIMO TDMA System

The capacity and robustness of cellular MIMO systems is very sensitive to other-cell interference, which will in practice necessitate network level interference reduction strategies. As an alternative to traditional static frequency reuse patterns, this paper investigates cooperatively scheduled transmissions among neighboring base stations. We analytically show that cooperatively scheduled transmission, which is well within the capability of present systems, can achieve an expanded multiuser diversity gain in terms of ergodic capacity as well as almost the same amount of interference reduction as conventional frequency reuse. From a theoretical standpoint, an interesting aspect of this analysis comes from an altered view of multiuser diversity in the context of a multi-cell system. Previously, multiuser diversity capacity gain has been known to grow as O(log log K), from selecting the maximum of K exponentially-distributed powers. Because the positions of the users are important in a multi-cell system, we find instead that the gain is O(radic(1og K)), from selecting the maximum of a compound lognormal-exponential distribution.