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In future cellular radio such as IMT-advanced systems, we will encounter a difficulty in sending uplink signals. This is because transmit power is limited by a battery in a terminal and we need higher transmit power to accommodate a wider frequency bandwidth in a higher frequency band. Virtual MIMO-based cooperative communication is expected to be a key technology to solve this problem. Especially,...
In the paper, performance of multiuser multiple-input multiple-output eigenbeam-space division multiplexing (E-SDM) systems in the downlink transmission is evaluated in both uncorrelated and correlated time-varying fading environments based on computer-generated data. In the ideal case, using the block diagonalization (BD) scheme, inter-user interference can be completely eliminated at each user;...
In a frequency-selective MIMO channel, the optimum beam- forming is achieved by using eigenvectors, i.e., eigenbeam- space division multiplexing (E-SDM), in the frequency domain. However, the calculation load of eigenvalue decomposition increases in proportion to the number of FFT points. In addition, eigenvectors without consideration of frequency continuity increase the delay spread of the effective...
MIMO measurement campaigns were conducted in indoor environments. Based on the measured data, this paper examines the channel auto-correlation and Doppler spectrum in a case where a receiver is moving with respect to a fixed transmitter in the propagation environments with static scatterers. The bit error rate (BER) performance of 4 times 4 MIMO eigenbeam-space division multiplexing(E-SDM) system...
In a frequency-selective MIMO channel, the optimum transmission is beamforming based on eigenvectors, i.e., eigenbeam-space division multiplexing (E-SDM), at each frequency point. However, the calculation load of eigenvalue decomposition at the transmitter increases in proportion to the number of frequency points. In addition, frequency-independent eigenvectors increase the delay spread of the effective...
Performance of multiple-input multiple-output (MIMO) systems applying the eigenbeam-space division multiplexing (E-SDM) technique may be degraded in time-varying fading environments due to a channel change during the time interval between the transmit weight matrix determination and the actual data transmission. We have proposed some channel prediction methods to compensate for the channel change...
MIMO channel characteristics and spatial multiplexing are investigated from the viewpoint of antennas and propagation in this paper. We conducted 4x4 MIMO channel measurement campaigns in an indoor propagation environment. Using the measured data, we examined the detail of the MIMO channels. The MIMO channels and eigenvalues are largely different for MIMO array orientations in an LOS environment....
MIMO space division multiplexing in an OFDM system (MIMO-OFDM) can achive high-data-rate transmission without additional frequency spectra. Furthermore, eigenbeam-space division multiplexing (E-SDM) which is also called the singular value decomposition (SVD) algorithm can provide maximum throughput in the MIMO channel when channel state information (CSI) is available at the transmitter. When the uplink...
Eigenbeam space division multiplexing systems in a multiple-input multiple-output channel require resource adaptation (a modulation scheme and transmit power allocation for each stream) optimized based on criteria such as throughput maximization. We propose a technique to simplify transmit resource control for the purpose of implementing the algorithm on an actual system. The proposed technique uses...
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