Interference Management Schemes with Finite Time Extension for X Networks

Abstract

In this dissertation, we research on the wireless communication network from the<br/> viewpoint of mitigating the condition of channel state information (CSI) and time extension<br/> required by interference alignment (IA).<br/> First, we investigate degrees of freedom (DoF) of the M by N single input single<br/> output (SISO) X channel with alternating channel state information at the transmitter<br/> (CSIT). It is known that the sum DoF of 2-user SISO X channel with synergistic alternating<br/> CSIT is the same as the sum DoF of 2-user (M = N = 2) SISO X channel<br/> with perfect CSIT [20]. As an extension of the 2-user case, achievable schemes of the<br/> M by N SISO X channel with synergistic alternating CSIT are proposed. It is shown<br/> that the proposedM_x0002_N X channel schemes with synergistic alternating CSIT achieve<br/> the sum DoF 2M=(M +1), which is better than the weighted sum DoF of the conventional<br/> schemes for M by N. The DoF of the proposed scheme with M = N = K is<br/> strictly better than the best known DoF for the K-user X channel with delayed CSIT.<br/> Secondly, we study an IA scheme with finite time extension and selection criterion<br/> with low computational complexity for X channel. We propose an IA scheme with a<br/> chain structure by Latin square in the K by 3 MIMO X channel. Since the proposed<br/> scheme can have more possible beamformers than the conventional schemes, its performance<br/> can be improved by the beamformer selection for a given channel. Also, we<br/> propose the CN based selection criterion with low computational complexity and verify<br/> its performance in terms of symbol error rate (SER) and sum-rate.<br/> Finally, we propose a resource allocation scheme and an interference cancellation<br/> scheme using Alamouti codes in a channel environment, where the device to device<br/> (D2D) communication and the uplink cellular mobile communication systems coexist.<br/> In such communication environment, users of two different systems should use<br/> time and frequency resources in a divided manner. In the proposed resource allocation