Ntt Docomo, Inc.

Agency for Science, Technology and Research

Tetsushi Abe

Satoshi Nagata

Kazuaki Takeda

Nobuhiko Miki

Yoshihisa Kishiyama

Daisuke Nishikawa

Yusuke Ohwatari

Hiroyuki Ishii

Mikio Iwamura

Hiromasa Fujii

Naoto Ookubo

Shigeru Tomisato

Hideaki Takahashi

Hitoshi Yoshino

Hirohito Suda

Takahiro Asai

Hidekazu Taoka

Yuki Inoue

Hui Shi

Sangiamwong Jaturong

Takefumi Yamada

Auer Gunther

Takehiro Nakamura

Anil Umesh

Motohiro Tanno

Zhongding Lei

Yuta Sagae

Naoto Okubo

Yasufumi Morioka

Francois Po Shin Chin

Tadashi Matsumoto

Yuuya Saitou

Zubin Bharucha

Sai Ho Wong

Alexander Tyrrell

To enable a mobile terminal apparatus to correctly demodulate a data signal in the case of applying Coordinated Multi-Point transmission (CoMP), particularly, JP-CoMP, a radio communication method of the invention is characterized in that a radio base station apparatus generates information for demodulation of a data signal in a mobile terminal apparatus in applying Coordinated Multi-Point transmission, and transmits the information for demodulation to a mobile terminal apparatus that performs Coordinated Multi-Point reception, and that the mobile terminal apparatus receives the information for demodulation of a data signal, and demodulates the data signal subjected to Coordinated Multi-Point reception using the information for demodulation.

Radio base station apparatus, mobile terminal apparatus, radio communication method and radio communication system

To provide a user terminal, radio base station apparatus, radio communication system and radio communication method that support increases in the number of users, a user terminal is provided with a reception section that receives a downlink control signal multiplexed into radio resources from the starting OFDM symbol to a predetermined OFDM symbol in a subframe, and a downlink control signal subjected to frequency division multiplexing with a downlink data signal into radio resources after the predetermined OFDM symbol, a retransmission check section that performs a retransmission check on the downlink data signal based on the downlink control signal subjected to frequency division multiplexing to output a retransmission response signal, and a selection section that selects a radio resource of an uplink control channel used in transmission of the retransmission response signal.

User terminal, radio base station apparatus, radio communication system and radio communication method

A radio communication method for a radio base station, apparatus that controls transmission of an aperiodic SRS (Sounding Reference Signal) by a mobile terminal apparatus is described. The radio communication method includes selecting a specific bit information piece to report to the mobile terminal apparatus, from a table having four bit in formation pieces including one bit information piece to indicate not to trigger the aperiodic SRS and three bit information pieces to indicate to transmit the aperiodic SRS using first to third default SRS parameters respectively, the four bit information pieces all being defined in a 2-bit bit field in downlink control information to be transmitted in one subframe, and transmitting, to the mobile terminal apparatus; the first to third default SRS parameters by higher layers and the specific bit information piece by a downlink control channel.

Radio base station apparatus, mobile terminal apparatus and radio communication method

The present invention is designed such that it is possible to optimize the effect of improving the efficiency of use of radio resources even when the number of user terminals to be multiplexed over the same radio resources is further increased. A user terminal performs downlink communication with a radio base station using a PDCCH resource region and a PDSCH resource region. The user terminal detects the starting position of the radio resources where the PDSCH and the PDCCH are frequency-division-multiplexed in the PDSCH resource region in the time direction, and receives the PDCCH that is frequency-division-multiplexed over the radio resources starting from the detected starting position.

User terminal, radio base station, downlink control channel receiving method and mobile communication system

The present invention is designed to provide a radio base station apparatus, a mobile terminal apparatus, a radio communication system and a radio communication method which can cope with an increased number of users. A radio base station apparatus is provided with: a signal generating section that generates a first downlink control signal and a second downlink control signal for a mobile terminal apparatus; a first multiplexing section that multiplexes the first downlink control signal on a control region up to a predetermined number of symbols from the top of a subframe; a second multiplexing section that frequency-division-multiplexes the second downlink control signal on radio resources from the next symbol in the control region to the last symbol of the subframe; and a transmission section that transmits the first downlink control signal multiplexed on the control region and the second downlink control signal multiplexed on the radio resources.

Radio base station apparatus, mobile terminal apparatus, radio communication system and radio communication method

The present invention provides a base station apparatus, a mobile terminal apparatus and a communication control method which can improve the accuracy of channel quality estimation. A communication control method includes the steps of: allocating a CSI-RS (Channel State Information-Reference Signal), which is a reference signal for downlink channel estimation, in resources for the CSI-RS that are defined for CSI-RS transmission; setting muting resources in the resources for the CSI-RS; and reporting parameters to specify the CSI-RS, including at least a transmitting subframe cycle, a subframe offset and transmission power, to a mobile terminal apparatus.

Base station apparatus, mobile terminal apparatus and communication control method

The present invention is designed to provide a radio communication system which can control uplink transmission power adequately even in an HetNet environment. A radio communication system having a first radio base station apparatus and a second radio base station apparatus that is configured to able to communicate with the first radio base station apparatus is provided; and, in this radio communication system, the first radio base station apparatus has a first communication quality measurement section that measures the received quality of an uplink reference signal transmitted from a user terminal, and generates first received quality information, and a reporting section that reports the first communication quality information to the second radio base station apparatus, and the second radio base station apparatus has a second communication quality measurement section that measures the received quality of the uplink reference signal transmitted from the user terminal, and generates second communication quality information, a correction value determining section that determines a correction value for the transmission power of the user terminal on the uplink based on the first communication quality information and the second communication quality information, and a reporting section that reports the determined correction value to the user terminal.

Radio communication system, radio base station apparatus, user terminal and radio communication method

The present invention is designed to minimize the increase of user terminal power consumption even when downlink control channels are extended. A radio base station apparatus having: an allocation section that allocates downlink control information in a first control region from a top of a radio frame to a predetermined OFDM symbol and in a second control region that is frequency-divided with a data region in a region that is time-divided with the first control region, and also allocates decoding control information that indicates a user terminal to perform a decoding process for the second control region, in the first control region; and a transmission section that transmits the downlink control information and the decoding control information; and a user terminal having: a receiving section that receives the downlink control information and the decoding control information from the radio base station apparatus; and a decoding section that controls the decoding process for the second control region based on the decoding control information received, are provided.

A radio base station apparatus that reports SRS (Sounding Reference Signal) transmission control information to a mobile terminal apparatus and controls transmission of an SRS by the mobile terminal apparatus is described. The radio base station includes an SRS setting section configured to select bit information to report to the mobile terminal apparatus, from a table having bit information to indicate not to trigger the SRS and bit information to indicate to trigger the SRS using a default SRS parameter and a reporting section configured to report the bit information for the mobile terminal apparatus using a downlink control channel.

The present invention is designed to reduce the increase in the amount of the calculation process in a mobile station and the amount of CSI feedback data, and also prevent the amount of overall system capacity from decreasing. This radio communication system () has a radio base station () which can form a plurality of beams that are vertically sectorized. The radio base station (), using an array antenna (), forms at least the first beam that is directed to the cell edge side and a second beam that is directed to the cell center side, in parallel. A mobile station () measures channel quality by extracting reference signals from each of the first beam and the second beam, generates a communication quality feedback signal including channel quality measured from at least one of the beams, and feeds this back to the radio base station () via the uplink.

Radio base station, user terminal, radio communication system and radio communication method

The present invention is designed to reduce interference from a macro base station to a small transmission power node. The present invention is characterized in providing a micro base station which forms, in a macro cell where a macro base station transmits a signal to a macro terminal, a micro cell where the micro base station transmits a signal to a micro terminal under control with low power, and this micro base station generates a PDCCH which includes downlink or uplink resource allocation information, and, in a non-transmission period in which the macro base station stops transmitting signals while leaving minimal quality measurement signals, shifts the transmission starting symbol of the PDCCH to a position where the PDCCH does not overlap the quality measurement signals.

Micro base station, user terminal and radio communication method

It is an object of the present invention to adequately report the SRS transmission timing and SRS parameters to a mobile terminal apparatus, when an aperiodic SRS is adopted, and efficiently use radio resources to be used for SRS transmission. A radio base station apparatus that reports SRS transmission control information to a mobile terminal apparatus and controls transmission of an SRS by the mobile terminal apparatus, and the radio base station apparatus has an SRS setting section that selects bit information to report to the mobile terminal apparatus, from a table having bit information to indicate not to trigger the SRS and bit information to indicate to trigger the SRS using a default SRS parameter, and a reporting section that reports the bit information for the mobile terminal apparatus using a downlink control channel.

In order to reduce radio resources allocated to PDCCHs and improve the data rate even when a plurality of component carriers are aggregated into a wide band, the present invention provides a base station apparatus having: a downlink control information generation section () configured to generate downlink control information (DCI) to demodulate PDSCHs that are sent independently in respective component carriers (CCs) allocated to a user terminal; and a transmitting section configured to transmit a PDCCH containing the downlink control information (DCI). The downlink control information (DCI) generated by the downlink control information generation section () is added with identification information (CIF) that is used to demodulate the PDSCHs assigned to the component carriers and is capable of identifying each of the component carriers.

Base station apparatus and communication control method

In order to transmit a paging to a user terminal with high quality, transmit a CSI-RS effectively and perform UL HARQ efficiently in HetNet, the present invention provides a radio communication method having the steps of: a micro base station which is arranged in a macro cell and forms a smaller micro cell than the macro cell, transmitting, to a user terminal, a signal having a CSI-RS subframe including a CSI-RS and a paging subframe including modification notification information indicating modification in system information and a control signal indicating not to measure a CSI-RS when the CSI-RS subframe and the paging subframe collide with each other; and the user terminal determining a CSI-RS subframe to measure the CSI-RS based on the control signal when the CSI-RS subframe and the paging subframe collide with each other.

User terminal, radio base station and radio communication method

A user equipmentaccording to the present invention is provided with a RSSI measuring unitthat, with regard to a predetermined sub-frame, is configured to measure a radio quality of a serving cell and a neighboring cell for all OFDM symbols within the predetermined sub-frame and that, with regard to sub-frames other than the predetermined sub-frame, is configured to measure the radio quality of the serving cell and the neighboring cell for OFDM symbols containing a reference signal within the sub-frames.

Growing community of inventors

Tokyo, Japan

Tetsushi Abe