Ntt Docomo, Inc.

Hidekazu Murata

Takahiro Asai

Yukihiko Okumura

Satoshi Suyama

Jiyun Shen

Susumu Yoshida

Jaturong Sangiamwong

To suppress reduction in system performance for mobile communications (group mobility) in a plurality of terminals existing inside the same moving object, a radio communication system for a plurality of user terminals existing inside a moving object and a radio base station is described. The user terminal receives a signal transmitted from the radio base station, and transmits the signal transmitted from the radio base station to a common reception apparatus disposed inside the moving object. The common reception apparatus detects a signal for each user terminal, based on signals transmitted from the plurality of user terminals, and transmits the detected signal to each user terminal. The user terminal receives the signal for the user terminal detected in the common reception apparatus to demodulate. Thus, for group mobility, it is possible to cancel interference among user terminals to improve the multiplexing effect, while suppressing communication overhead.

Radio communication system, common reception apparatus and user terminal

A radio communications apparatus is disclosed which includes a generator which generates a transmit frame; and a transmitter which transmits the transmit frame via multiple transmit antennas. In the radio communications apparatus, the transmit frame includes a predetermined number of resource elements having a predetermined frequency bandwidth and a predetermined symbol period, and the generator generates the transmit frame such that the number of transmit antennas which are identifiable from a location of the resource element taken up by a pilot signal in a certain transmit frame is less than the number of transmit antennas which are identifiable from the location of the resource element taken up by the pilot signal in a retransmission transmit frame of the certain transmit frame.

Radio communications apparatus, radio communications method, and radio communications system for reducing overhead of a transmit frame

Growing community of inventors

Kyoto, Japan

Hidekazu Murata