DoF region for two-cell multiuser MIMO uplink channels

In this paper, we present a method for obtaining achievable Degree-of-Freedom (DoF) region for the uplink channels of two-cell cellular networks by interference alignment without symbol extension. Based on quotient singular value decomposition (QSVD), the method gets all possible divisions of signal and interference subspaces at each receiver. These subspaces from different receivers are then synthesized to result in transmit subspace for each transmitter, the dimension of which is the achievable DoF. Compared to existing methods, the proposed one can be applied to cellular systems with arbitrary number of terminals and transmit and receive antennas.