The Experts below are selected from a list of 90 Experts worldwide ranked by ideXlab platform

Hidekazu Taoka - One of the best experts on this subject based on the ideXlab platform.

  • muting Based partially non orthogonal block diagonalization in multiuser mimo with limited channel state information feedback
    Vehicular Technology Conference, 2011
    Co-Authors: Yuki Tajika, Kenichi Higuchi, Hidekazu Taoka
    Abstract:

    This paper investigates a precoding method in downlink multiuser Multiple-input Multiple-output (MIMO) transmission employing Multiple Base Station (BS) cooperation where the sets of user equipment basically feedback the instantaneous channel state information (CSI) only to the nearest BS, but the users near the cell edge additionally feedback the instantaneous CSI to the second nearest BS among the cooperating BSs. The proposed precoding method is categorized into multi-cell processing, in which the transmission information sent to a user is shared by the cooperating BSs in order to utilize fully the degrees of freedom of the spatial channel, and is Based on block diagonalization of the channel matrix. However, since some elements of the channel matrix are unknown, we allow inter-user interference to users with limited instantaneous CSI feedback. More specifically, in the proposed method, the elements corresponding to the unknown instantaneous CSI in the overall channel matrix are muted by setting these elements to zero, and the standard generation procedure of the block diagonalization precoding matrix is performed on the muted channel matrix. The proposed method efficiently utilizes the degrees of freedom of the spatial channel compared to the case with full orthogonal transmission at the cost of increased inter-user interference. Simulation results show that the proposed method decreases the transmission power for a given capacity requirement compared to the case with full orthogonal transmission.

Yuki Tajika - One of the best experts on this subject based on the ideXlab platform.

  • muting Based partially non orthogonal block diagonalization in multiuser mimo with limited channel state information feedback
    Vehicular Technology Conference, 2011
    Co-Authors: Yuki Tajika, Kenichi Higuchi, Hidekazu Taoka
    Abstract:

    This paper investigates a precoding method in downlink multiuser Multiple-input Multiple-output (MIMO) transmission employing Multiple Base Station (BS) cooperation where the sets of user equipment basically feedback the instantaneous channel state information (CSI) only to the nearest BS, but the users near the cell edge additionally feedback the instantaneous CSI to the second nearest BS among the cooperating BSs. The proposed precoding method is categorized into multi-cell processing, in which the transmission information sent to a user is shared by the cooperating BSs in order to utilize fully the degrees of freedom of the spatial channel, and is Based on block diagonalization of the channel matrix. However, since some elements of the channel matrix are unknown, we allow inter-user interference to users with limited instantaneous CSI feedback. More specifically, in the proposed method, the elements corresponding to the unknown instantaneous CSI in the overall channel matrix are muted by setting these elements to zero, and the standard generation procedure of the block diagonalization precoding matrix is performed on the muted channel matrix. The proposed method efficiently utilizes the degrees of freedom of the spatial channel compared to the case with full orthogonal transmission at the cost of increased inter-user interference. Simulation results show that the proposed method decreases the transmission power for a given capacity requirement compared to the case with full orthogonal transmission.

  • partially non orthogonal block diagonalization Based precoding in multiuser mimo with limited channel state information feedbacks
    Personal Indoor and Mobile Radio Communications, 2010
    Co-Authors: Yuki Tajika, Ryosuke Kimura, Masahiro Watanabe, Kenichi Higuchi
    Abstract:

    We consider a precoding method in downlink multiuser Multiple-input Multiple-output (MIMO) transmission with Multiple Base Station (BS) cooperation where some of the instantaneous channel state information (CSI) is not available at the BSs. The proposed precoding method is Based on block diagonalization of the channel matrix. However, since some elements of the channel matrix are unknown, we allow a partially non-orthogonal transmission. More specifically, we allow inter-user interference to users with limited instantaneous CSI feedback from the channel where the instantaneous CSI of that user is not obtained at the BSs. The other inter-user interferences are set to zero Based on the block diagonalization of the channel matrix. The proposed method efficiently uses the degree of freedom of the spatial channel compared to the case with full orthogonal transmission at the cost of increased inter-user interference to the users with limited instantaneous CSI feedback. Simulation results show that the proposed method increases the capacity for a given transmission power or decreases the transmission power for a given capacity requirement compared to the case with full orthogonal transmission.

Kenichi Higuchi - One of the best experts on this subject based on the ideXlab platform.

  • muting Based partially non orthogonal block diagonalization in multiuser mimo with limited channel state information feedback
    Vehicular Technology Conference, 2011
    Co-Authors: Yuki Tajika, Kenichi Higuchi, Hidekazu Taoka
    Abstract:

    This paper investigates a precoding method in downlink multiuser Multiple-input Multiple-output (MIMO) transmission employing Multiple Base Station (BS) cooperation where the sets of user equipment basically feedback the instantaneous channel state information (CSI) only to the nearest BS, but the users near the cell edge additionally feedback the instantaneous CSI to the second nearest BS among the cooperating BSs. The proposed precoding method is categorized into multi-cell processing, in which the transmission information sent to a user is shared by the cooperating BSs in order to utilize fully the degrees of freedom of the spatial channel, and is Based on block diagonalization of the channel matrix. However, since some elements of the channel matrix are unknown, we allow inter-user interference to users with limited instantaneous CSI feedback. More specifically, in the proposed method, the elements corresponding to the unknown instantaneous CSI in the overall channel matrix are muted by setting these elements to zero, and the standard generation procedure of the block diagonalization precoding matrix is performed on the muted channel matrix. The proposed method efficiently utilizes the degrees of freedom of the spatial channel compared to the case with full orthogonal transmission at the cost of increased inter-user interference. Simulation results show that the proposed method decreases the transmission power for a given capacity requirement compared to the case with full orthogonal transmission.

  • partially non orthogonal block diagonalization Based precoding in multiuser mimo with limited channel state information feedbacks
    Personal Indoor and Mobile Radio Communications, 2010
    Co-Authors: Yuki Tajika, Ryosuke Kimura, Masahiro Watanabe, Kenichi Higuchi
    Abstract:

    We consider a precoding method in downlink multiuser Multiple-input Multiple-output (MIMO) transmission with Multiple Base Station (BS) cooperation where some of the instantaneous channel state information (CSI) is not available at the BSs. The proposed precoding method is Based on block diagonalization of the channel matrix. However, since some elements of the channel matrix are unknown, we allow a partially non-orthogonal transmission. More specifically, we allow inter-user interference to users with limited instantaneous CSI feedback from the channel where the instantaneous CSI of that user is not obtained at the BSs. The other inter-user interferences are set to zero Based on the block diagonalization of the channel matrix. The proposed method efficiently uses the degree of freedom of the spatial channel compared to the case with full orthogonal transmission at the cost of increased inter-user interference to the users with limited instantaneous CSI feedback. Simulation results show that the proposed method increases the capacity for a given transmission power or decreases the transmission power for a given capacity requirement compared to the case with full orthogonal transmission.

J H Winters - One of the best experts on this subject based on the ideXlab platform.

  • the diversity gain of transmit diversity in wireless systems with rayleigh fading
    IEEE Transactions on Vehicular Technology, 1998
    Co-Authors: J H Winters
    Abstract:

    In this paper, we study the ability of transmit diversity to provide diversity benefit to a receiver in a Rayleigh fading environment. With transmit diversity, Multiple antennas transmit delayed versions of a signal to create frequency-selective fading at a single antenna at the receiver, which uses equalization to obtain diversity gain against fading. We use Monte Carlo simulation to study transmit diversity for the case of independent Rayleigh fading from each transmit antenna to the receive antenna and maximum likelihood sequence estimation for equalization at the receiver. Our results show that transmit diversity with M transmit antennas provides a diversity gain within 0.1 dB of that with M receive antennas for any number of antennas. Thus, we can obtain the same diversity benefit at the remotes and Base Stations using Multiple Base-Station antennas only.

Jinho Choi - One of the best experts on this subject based on the ideXlab platform.

  • Opportunistic Beamforming With Single Beamforming Matrix for Virtual Antenna Arrays
    IEEE Transactions on Vehicular Technology, 2011
    Co-Authors: Jinho Choi
    Abstract:

    Opportunistic beamforming is a promising technique for downlink channels in cellular systems. When opportunistic beamforming is to support Multiple users at a time, it is important to form Multiple beams with as little interference as possible. In the conventional approach with limited feedback of channel state information from users, the best beamforming matrix can be selected from a set of Multiple beamforming matrices. Thus, at each time when a different set of users are selected by a scheduler, a new beamforming matrix has to be found, which may require excessive complexity. To avoid this problem, in this paper, we propose an opportunistic beamforming approach with a single fixed beamforming matrix for Stationary users. Since the beams are fixed, we only need to perform user selection (and power allocation if necessary). It is also shown that the proposed approach is suited for a distributed virtual antenna array built by Multiple Base Station or access point units, since the intercorrelation between the users' channel vectors in this case allows effective opportunistic beamforming Based on user classification in conjunction with a single beamforming matrix.