Ntt Docomo, Inc.

Tokyo Institute of Technology

Hiromasa Fujii

Hirohito Suda

Hitoshi Yoshino

Takahiro Asai

Hiroki Harada

Shunji Miura

Jiyun Shen

Tomoyuki Ohya

Shigeru Tomisato

Takefumi Yamada

Tetsu Tanaka

Takatoshi Sugiyama

Hiroshi Suzuki

Yukihiko Okumura

Tetsushi Abe

Hidetoshi Kayama

Hiroto Yasuda

Junichiro Hagiwara

Satoshi Suyama

Noriyuki Maeda

Kazuhiko Fukawa

Hui Shi

Tadashi Matsumoto

Hiromitsu Asakura

Masaharu Hata

Ohya Tomoyuki

Tomoyuki Oya

A CRS base station () includes a transmitting section configured to transmit a synchronization establishment signal, a receiving section configured to receive a random access signal corresponding to the synchronization establishment signal, a determining section configured to determine whether or not the random access signal received by the receiving section has been transmitted from an MCS terminal () and an interference reduction processing section configured to perform interference reduction processing on the MCS terminal () when the determining section determines that the random access signal has been transmitted from the MCS terminal ().

User terminal

The present invention provide a transmitting/receiving device that includes a sensing period information setting part for, in an interfering system that shares at least a part of a frequency band with an interfered system, setting sensing period information that shows a sensing period for a signal using a shared frequency band; and a transmission prohibition period information notifying part for notifying a terminal in the interfering system of transmission prohibition period information for prohibiting transmission processing in the interfering system until an end of the sensing period, a maximum transmission period for one transmission by the terminal in the interfering system prior to a start point of the sensing period.

Transmitting/receiving device, wireless terminal device and wireless communication method for suppression of intra-system interference

A wireless station in a second communication system, with at least a portion of a first frequency band used in a first communication system and a portion of a second frequency band used in the second communication system being shared or neighboring, the wireless station including a waveform characteristic quantity extracting unit that extracts a waveform characteristic quantity which shows a statistical characteristic of a signal received from the first communication system; a communication parameter determining unit that determines communication parameters to be used for the wireless station in the second communication system depending on a determination result of whether the extracted waveform characteristic quantity is of a predetermined waveform characteristic quantity for reducing an interference; and a transmission and reception unit that transmits and receives a wireless communication signal in the second communication system in accordance with the determined communication parameters.

Wireless station, interference avoidance method, and system for interference avoidance

Radio base station and frequency band sharing method

A signal detection apparatus includes: a unit configured to select a particular detection target signal from among plural candidates of detection target signals; a unit configured to calculate a cyclic autocorrelation value at a center coordinate point specified by at least a cyclic parameter and a shift parameter of the particular detection target signal; a unit configured to calculate a cyclic autocorrelation value of each of (L&#x2212;1) coordinate points belonging to a common area that is used commonly for different detection target signals; a unit configured to calculate a test statistic of the particular detection target signal; and a unit configured to determine presence or absence of the particular detection target signal according to a comparison result between the test statistic and a threshold, wherein the test statistic is calculated by using the cyclic autocorrelation value in each of the (L&#x2212;1) coordinate points belonging to the common area.

Signal detection apparatus and signal detection method

The invention has a step where a transmitting station in a second radio communication system determines whether transmission of a second radio communication system signal using a shared frequency band is possible or not based on load information of a first radio communication system broadcast from a base station in the first radio communication system, a step where the transmitting station in the second radio communication system calculates predicted interference power caused in a receiving station in the first radio communication system by the second radio communication system signal transmitted using the shared frequency band, and a step where the base station in the first radio communication system increases an allowable interference level of a first radio communication system signal transmitted using the shared frequency band based on the predicted interference power broadcast from the transmitting station in the second radio communication system.

Radio station, transmitting station, and frequency band sharing method

The second radio communication system selects one or more of the sub-carriers Sto be used in accordance with a condition of the sub-carriers S. The second radio communication system transmits a radio signal by using the sub-carriers Sselected. In the selection of sub-carrier, the sub-carrier Slocated between the plurality of sub-carriers Sradiated in the frequency band BW

Radio communication system

A radio communication apparatus includes: a receiving unit configured to receive a cognitive signal including system information of each of a plurality of systems; a metric unit configured to prepare metric information indicating relationship degree between the radio communication apparatus and a communication system to which the radio communication apparatus does not belong; a condition determination unit configured to determine whether a restriction should be imposed on transmission by the radio communication apparatus based on the system information and the metric information; and a transmission unit configured to transmit a signal using predetermined radio resources when transmission by the radio communication apparatus is not prohibited.

Radio communication apparatus and radio communication method in communication system

Disclosed is a signal generation device that employs a transmission method using inverse Fourier transform. The signal generation device includes: a modulation unit which modulates transmission data to obtain modulation data; a serial-parallel conversion unit which converts the modulation data input in series to parallel data of a predetermined size smaller than the size of inverse Fourier transform; a duplication unit which selects and duplicates all or a portion of the parallel data to obtain duplication data; a first time-axis shift unit which shifts the duplication data along the time axis to obtain time-axis shift data; and an inverse Fourier transform unit which carries out inverse Fourier transform on the parallel data obtained by the serial-parallel conversion unit and the time-axis shift data obtained by the first time-axis shift unit.

Signal generation device and signal generation method

When a frequency band is shared between a large cell system having a large cell base station and a small cell system having a small cell base station, the large cell base station dynamically controls dedicated resources for the large cell base station and shared resources for both the large cell base station and the small cell base station based on predetermined information, broadcasts allocation information of dedicated resources for the large cell base station and shared resources for both the large cell base station and the small cell base station, to the small cell base station belonging to the own cell, and the small cell base station belongs to at least one large cell base station and determines resource assignment in the own cell based on the resource allocation information broadcast from the large cell base station.

Radio communication method and radio base station

A signal detection apparatusfor determining whether a detection target signal is included in a received radio signal, includes: a waveform feature amount calculation unitconfigured to calculate a waveform feature amount Rrepresenting a waveform feature; a test statistic calculation unitconfigured to calculate test statistic Zof each detection target signal by using the waveform feature amount; and a signal decision unitconfigured to determine presence or absence of each detection target signal by comparing the test statistic Zof each detection target signal with a threshold &#x393;, wherein, under a condition where a specific detection target signal is removed, the test statistic calculation unit calculates a test statistic for a detection target signal which is not removed, and the signal decision unit determines presence or absence of the detection target signal by comparing the calculated test statistic with the threshold.

Signal detection apparatus and signal detection method for use in radio station of radio communication system

The present invention is to provide a communication channel with a low inter-cell interference while suppressing variation in the amount of inter-cell interference. Provided is a base station arranged in a radio communication system configured to implement a frequency division multiple access method by using a frequency division multiplexing method as a modulation method, and configured of cells each divided into an inner region and an outer region. The base station includes an allocation controller configured to perform subchannelization using a perfectly-orthogonal channel in the outer region of the cell, and to perform subchannelization using a quasi-orthogonal channel in the inner region of the cell.

Radio communication apparatus and radio communication method

A transmitter which transmits information in transmission frame to a receiver, the transmission frame including multiple transmission symbols and guard intervals obtained by replicating a fixed time period of a transmission symbol, generates a transmission frame by making phases of one transmission symbol out of two transmission symbols and a guard interval thereof continuous with phases of the other transmission symbol and a guard interval thereof, when the two continuous transmission symbols are the same.

Transmitter and method for configuring transmission frame

A disclosed radio communication apparatus includes an intermediate band detecting unit detecting an intermediate band which is a band between a first frequency band and a second frequency band which are allocated to a same mobile communication system or different mobile communication systems, a use status detecting unit detecting an uplink/downlink multiplexing method used in each of the first frequency band and the second frequency band, and a determination unit determining, based on the intermediate band and the uplink/downlink multiplexing method, the uplink/downlink multiplexing method usable in the intermediate band and a guard band in which use of frequencies are prevented, the guard band being included in the intermediate band.

Growing community of inventors

Yokosuka, Japan

Hiromasa Fujii