Ntt Docomo, Inc.

Ansuman Adhikary

Haralabos Papadopoulos

A method and apparatus is disclosed herein for channel state information dissemination for multi-user (MU) multiple-input multiple-output (MIMO) (MU-MIMO) transmission schemes based on outdated channel state information. In one embodiment, a method for disseminating channel state information (CSI) coefficients from a first user terminal, where each CSI coefficient corresponds to the CSI previously observed by the first user terminal during transmission resource blocks used by a base station to communicate information to a second set comprising at least one user terminal and not including the first user terminal, comprises: broadcasting by the base station the channel state information (CSI) of each user terminal in the second set of user terminals, on the subset of transmission resources used by the base station to communicate information to each user terminal in the second set; receiving observations of these transmissions by the first user terminal; performing, at first user terminal, eavesdropper channel selection of a subset of CSI coefficients between the base station and the eavesdropping first-user terminal for uplink CSI feedback, the subset chosen out of the set of CSI coefficients between base station and the first user-terminal on the transmission resources used by the base station to communicate information to each user terminal in the second set; scheduling the subset of the selected CSI coefficients for uplink transmission; and transmitting the subset of the selected CSI coefficients via the uplink transmission.

Method and apparatus for efficient channel state information dissemination for MU-MIMO transmission schemes based on outdated channel state information

A method and apparatus is disclosed herein for scheduling and MU-MIMO transmission based on outdated channel state information. In one embodiment, the multi-user (MU)-MIMO wireless communication system has a multi-antenna transmitter and L user terminals, and the method comprises scheduling a pair of user packets for a round-2 transmission to form one MAT session using outdated channel state information at the transmitter (CSIT), including a first packet destined for a first user terminal and a second packet destined for a second user terminal, based on knowledge of user channels from transmissions to some or all L user terminals into and based on a utility function, combining eavesdropped observations from two of the plurality of round-1 transmissions, the eavesdropped observations including information indicative of round-1 eavesdropped channels feedback from the first and second user terminals, and transmitting the combined observations of the pair of user packets as part of the round-2 transmission.

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Los Angeles, CA, United States of America

Ansuman Adhikary