Base station cooperation in multi-cellular system using multi-stream communications

In multiple transmitter multiple receiver (MTMR) communication represented by multi-cellular systems, receivers (UTs: user terminals) might be located far from their target transmitter (BSs: base stations), and suffered from attenuation of the desired signal and strong interferences from nontarget transmitters. As a solution to this problem, this paper considers multi-cellular system using the cooperation of BSs in which multi-stream transmission based on MIMO (multiple input multiple output) structure is adopted. Here studied is two types of BS cooperation, the first is the case all the BSs share only CSI (channel state information), and the second is the case data is also shared among BSs (virtual array). The performance of several algorithms including the multi-stream version of partial zero forcing (PZF) algorithms are evaluated, and it is shown that the cooperation is useful also in multi-stream transmission.