Intelligent Subcarrier Allocation In MIMO-OFDM System And Other Cell Interference Suppression

MIMO systems make high data rate transmission possible in its decomposed spatial subchannels, on the other hand, OFDM technology facilitates efficient spectrum utilization. Radio Resource Management of MIMO-OFDM systems becomes key technology in next generation wireless communication, moreover, other-cell interference(OCI) bounds improvement of system capacity. Holding optimizing system capacity in mind, this dissertation mainly focus on the subcarrier allocation in multiuser MIMO-OFDM system and interference suppression in cellular MIMO systems. Theory research, simulation and comparison are provided. The main work includes the following:Two exclusive subcarrier allocation strategies'capacity, which are base on maximum Frobenius norm and determinant of channel matrix respectively, are investigated in multiuser MIMO-OFDM system. In view of exclusive subcarrier allocation strategies only allocate subcarrier in frequency, a space-frequency(SF) adaptive subcarrier allocation scheme is proposed,which optimized user combination in both of transmit antenna and subcarrier to maximize system capacity. Simulation results witness the capacity enhancement and multiuser diversity of the proposed scheme against exclusive allocation scheme. The enhancement grows linearly with number of transmit antenna. To further reduce complexity of the proposed scheme, Genetic Algorithm(GA) is introduced for SF subcarrier allocation. The first modified algorithm apply GA directly to the SF scheme, the second one selects transmit antennas with maximum Frobenius norm in the receivers and feed back these antenna indexes to the transmitter, GA searches user combination in the transmitter. Numerical results shows the GA based algorithm reduce the complexity evidently with litter capacity loss, and the second algorithm has lower complexity. An other-cell interference(OCI) suppressed block diagonalization (BD) scheme is proposed. This scheme doesn't need channel state information(CSI) of interfering cells, and needs only the covariance of interference and noise, which can be estimated by receivers, to design pre-coding matrix to suppress interference. Simulation results show that the OCI suppressed BD gains higher sum capacity compared with the one with no OCI suppression. However, due to not eliminating OCI, a sum capacity gap between the proposed scheme and BD with no interference is witnessed, and the gap become bigger when INR increases.Conclude above, the scheme proposed for subcarrier allocation in MIMO-OFDM systems and OCI suppression in cellular MIMO systems provide reference in next generation mobile communication.