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Interference Management With Limited Channel Knowledge

Posted on:2016-06-28Degree:DoctorType:Dissertation
Country:ChinaCandidate:S X PengFull Text:PDF
GTID:1108330467998471Subject:Information and Communication Engineering
Abstract/Summary:PDF Full Text Request
With growth of the scale and requirement for wireless communication system, the interference has become the major issue that limits the performance of wireless networks. Efficient interference management will play a crucial role for the next generation wireless communication system. However, the existing theories and schemes of interference management still have many problems. Especially, when available channel state information is limited, many current results on the channel capacity and interference management schemes in wireless communication system will face great challenges. In this dissertation, we are devoted to address the performance limit and interference management schemes of the multi-user wireless network when available channel state information is limited, including design of the numerical interference alignment with local chanel state information from communication pairs, spatial degree of freedom for the interference channel with local channel state information at transmitters, interference management schemes with limited-rate precoding matrix feedback. The contents of this dissertation are listed as follows.We propose a distributed signal subspace interference alignment algorithm for single beam K-user (K>3) MIMO interference channel based on sum rate maximization and game theory. A framework of game theory is provided to study relationship between interference signal subspace and altruistic-egoistic bayesian game cost function. We demonstrate that the asymptotic interference alignment under the proposed scheme can be realized through a numerical algorithm using local channel state information at transmitters and receivers. Simulation results show that the proposed scheme can achieve the total degree of freedom that is equivalent to the Cadambe-Jafar interference alignment algorithms with perfect channel state information. Furthermore, proposed scheme can effectively minimize leakage interference in desired signal subspace at each receiver and obtain a moderate average sum rate performance compared with the several existing interference alignment schemes.We discuss inner bound and outer bound for the total number of spatial degrees of freedom (DoF) of the K-user MIMO interference channel with only local channel state information at each transmitter (CSIT) when channel extensions is disabled over time and frequency dimensions. We firstly provide a constructive proof of achievability of the DoF based on zero forcing for two-user MIMO interference channel with M1, M2antennas at transmitter1,2and N1, N2antennas at the corresponding receivers when only local channel state information (CSI) is available at the transmitters. Then the total achievable DoF and interference management scheme for3-user interference channel with specific antenna configuration is presented by comparing the number of equations and the number of variables. We apply interference zero-forcing scheme and signal subspace analysis to generalize the idea of interference management for this special case to the common3-user and K-user MIMO symmetric interference channel and establish that the the inner bound on total spatial DoF min(K min(M,,N,),max(M,,N,))is achievable in K-user MIMO symmetric interference channel with Mt transmitter antennas and Nr receiver antennas. We also provide the proof of an outer bound on spatial DoF for the K-user MIMO symmetric interference channel with only local CSI at each transmitter and indicate that the inner bound and outer bound are tight when the number of receiver antennas is not less than the number of transmitter antennas.The sufficient conditions of spatial interference alignment operating under a realistic limited feedback are provided for a K-user MIMO interference channel. The transmit precoder’s matrix index is fed back to the corresponding transmitter through an error-free non-interfered link. We investigate the number of feedback bits required for achieving the maximum theoretical multiplexing gain for the spatial interference alignment schemes considered and demonstrate the feasibility of spatial interference alignment under the limited feedback constraint investigated. It is shown that in order to maintain the same spatial multiplexing gain as that of the idealized scheme relying on perfect channel state information, the number of feedback bits per receiver scales as Nd>di(M-di)log2P, where M and dt denote the number of transmit (receive) antennas and the number of data steams for user i, P is the total transmit power. Finally, the analytical results are verified by simulations for realistic practical interference alignment schemes relying on limited precoding matrix feedback indices.
Keywords/Search Tags:Wireless communication network, Multiple antennas, Interference alignment(IA), Signal subspace, Local channel state information (Local CSI), Limitedfeedback
PDF Full Text Request
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