NTT DoCoMo

About: NTT DoCoMo is a based out in . It is known for research contribution in the topics: Base station & Mobile station. The organization has 4032 authors who have published 8655 publications receiving 160533 citations.

Base station and user equipment

Abstract: The present disclosure relates to techniques for implementing efficient beam forming in 3D MIMO. One aspect of the present invention relates to abase station, comprising: a beam forming unit configured to form multiple directional beams in accordance with a predetermined beam arrangement; a transmission and reception unit configured to transmit reference signals in the formed multiple directional beams; and a feedback information acquisition unit configured to acquire feedback information from user equipment receiving the reference signals.

Enhanced local access in mobile communications with fdd resource allocation

Abstract: A hybrid user equipment and small-node device data offloading architecture is provided. In this hybrid architecture, the small-node device includes a backhaul link to a telecommunication network and/or the Internet. The user equipment can send and receive data through the small-node device using the backhaul link according to a half-duplex FDD radio resource assignment in a wireless link between the user equipment and the small-node device.

Handover resource optimization

Abstract: A method for maintaining a quality of service in a wireless communication network is introduced. A reservation is created in a first data path between a home agent and a first foreign agent for data flow between the home agent and a wireless terminal. When the wireless terminal associates with a second foreign agent, a quality of service supportive second data path may be created between the first foreign agent and the second foreign agent. The data flow may be routed over the first and second data paths to maintain the quality of service for the data flow. A wireless communication network may include first downstream and reverse tunnels coupling a home agent and a first foreign agent, each tunnel having a reservation to maintain a quality of service. Second downstream and reverse tunnels may couple a home agent and a second foreign agent. All or part of the resources reserved by the first tunnels may be shared with the second tunnels when a wireless terminal hands over from the first foreign agent to the second foreign agent.

Method for varying transmit power patterns in a multi-cell environment

Abstract: A method and apparatus is disclosed herein for varying transmit power patterns in a multi-cell wireless transmission environment. In one embodiment, the method comprises varying transmit power coordination patterns for base stations in the wireless communication system to jointly vary base station power over a set of virtual channels over base stations within a cluster and across clusters of base stations; and jointly transmitting by groups of the base stations to one or more user terminals in their respective clusters based on the transmit power coordination patterns.

Techniques for Multi-User MIMO with Two-Way Training

Abstract: We consider forward-link multiuser MIMO transmission, whereby K users are served by a base station with a large number of (potentially distributed) transmit antennas. We address the problem of channel state information (CSI) mismatch between the transmitter and the receivers with a two-way training scheme. In a quasi-static setting, the proposed scheme requires only K pilot symbols for uplink training and as little as one symbol for downlink training. In particular, we show that the performance of the system where the receiver has perfect channel knowledge can be approached with a small value of downlink training symbols. We consider two variants of linear MMSE precoders that take into account the quality of the channel state information at the transmitter and demonstrate that robust high sum-rate systems can be designed that rely on single-antenna receivers, provided that a large enough number of antennas is used for transmission. Finally, we sketch an example of implementations for the equal rate case.