Kazuyoshi Oshima

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This paper proposes a novel downlink spatial scheduling algorithm in multiuser MIMO systems, which selects good combination of terminals and base station(BS)’s transmit beams so that the BS’s beams nullify inter-stream interference at the selected terminals. In the derivation process, we reveal new property that the optimization problem of downlink spatial(More)
This paper presents uplink spatial scheduling with adaptive transmit beamforming, where terminals perform system-based transmit beamforming in multiuser multi-input multi-output (MIMO) systems. In the presented spatial scheduling, the base station (BS) selects appropriate combination of terminals and their transmit beamforming among possible terminals. In(More)
This paper proposes a pilot-based channel state information (CSI) feedback in time-division duplex (TDD) / multi-input multi-output (MIMO) system, which enables the transmitter to perform transmit beamforming considering the receiver’s interference. In the proposed method, the receiver sends reverse-link pilot signals spatially prefiltered by linear(More)
This paper presents downlink spatial scheduling which nullifies interference among multiplexed signals perfectly in multiuser MIMO systems. Under the base station’s zero-forcing transmit beamforming, each terminal can receive packet of interest without interference from the other multiplexed packets. The scheduling algorithm successively selects appropriate(More)
This paper studies a multiband mobile communication system to support both high data rate services and wide service coverage, using high and low frequency resources with different propagation characteristics. In the multiband system, multiple frequency bands are managed by a base station and one of the frequency bands is adaptively allocated to a terminal(More)