Topological Interference Alignment Techniques Research For MIMO Networks

The topological interference alignment(TIA)is to design the interference alignment(IA)scheme under the condition that there is only the topology information about the network known to the transmitters.The topology information consists of a coarse knowledge of the channel state information which only justifies the interference links as strong or weak.Compared to the IA scheme under the perfect channel state information(CSI),the TIA is much more practical and it has a significant impact on exploring the potential ability of the wireless communication system.For the general multiple input multiple output(MIMO)interference channel(IC)and MIMO interference broadcast channel(IBC),this thesis proposes the concrete TIA schemes,and then analyzes the achievable degrees of freedom(Do F)of the system.For general MIMO IC system,a matrix completion based TIA scheme has been proposed in this thesis,and its core idea is to construct the partially connected model for the MIMO IC according to the topology information about the network at first,and then map it into a partially connected model of the corresponding single input single output(SISO)IC.Meanwhile,the solution to the TIA problem of SISO IC can be obtained based on the matrix completion method.At last,this thesis jointly designs the precoding matrix and decoding matrix for the MIMO IC and utilizes the time extension and the transpose operator to achieve the goal of TIA.For general MIMO IBC system,two TIA schemes have been proposed in this thesis,one is user compression based TIA scheme and the other is base station extension based TIA scheme.The core idea of the MIMO IBC TIA scheme is to construct the partially connected model of the MIMO IBC network according to the topology information at first.Then the partially connected model of the MIMO IBC can be transformed into that of a MIMO IC based on the user compression method or the base station extension method.Furthermore,the partially connected model of MIMO IC can be mapped into that of a SISO IC.At last,based on the solution to the SISO IC TIA problem to jointly design the concrete TIA scheme for the original MIMO IBC networks.Especially,the inter-cell interference is eliminated by the jointly design of the precoding matrix and decoding matrix based on the topology information,while the intra-cell interference is eliminated according to the zero-forcing scheme at the transmitters.In addition,this thesis analyzes the achievable Do F of the networks after employing the TIA schemes,and the Do F results can be treated as a Do F inner bound of the system which gives insights to the TIA research about the MIMO networks,especially a significant impact on the achievable Do F under the topology information.