Fujitsu Corporation

Takato Ezaki

Dai Kimura

Daisuke Jitsukawa

Yoshihiro Kawasaki

Tsuyoshi Shimomura

Kazuya Kobayashi

Yuya Harada

Kazuto Sato

Shin Hosokawa

Shunsuke Iizuka

A communication apparatus that communicates with a terminal device using a multi-input multi-output (MIMO) data transfer method includes: a memory; and a processor coupled to the memory and configured to: estimate a reception signal to interference ratio (SIR) of a wireless propagation path between the communication apparatus and the terminal device; acquire an SIR offset value for a transmission rank based on a state of occurrence of transfer errors; and switch the transmission rank based on the reception SIR and an SIR offset value for the transmission rank.

Communication apparatus, wireless communication system, and transmission rank switching method

A re-transmission control method of downlink data to be transmitted from a radio base station to a radio terminal includes: by the radio terminal, transmitting information regarding decoding performance of the radio terminal to the radio base station; receiving the downlink data from the radio base station; transmitting a re-transmission request of the downlink data to the radio base station in a case where an error in the downlink data is detected; receiving a re-transmission configuration based on the information regarding decoding performance of the radio terminal, from the radio base station in a physical downlink control channel (PDCCH), after transmission of the re-transmission request; receiving the downlink data re-transmitted from the radio base station; and decoding the re-transmitted downlink data in accordance with the re-transmission configuration.

Re-transmission control method, radio terminal, and radio base station

A wireless communication system includes a terminal; and a base station configured to perform uplink scheduling. The terminal transmits to the base station, a signal that includes a scheduling request and a buffer state index value of the terminal. The base station performs scheduling for the terminal, based on the buffer state index value.

Wireless communication system, base station, and terminal

A base station including: a memory, and a processor configured to: determine whether each random access signal is detected or not by comparing each of specified characteristics of each of radio resources prepared for each random access signal with a detection threshold, each of the specified characteristics relating to each reception power of each of the radio resources prepared for each random access signal, the radio resources being divided into first radio resources and second radio resources, the first radio resource being prepared for dedicated random access signals each transmitted from each terminal in response to each request signal transmitted from the base station, and determine the detection threshold based on each of the specified characteristics of each of unused first radio resources, each of the unused first radio resource being each of the first radio resources for which each request signal has not been transmitted from the base station.

Base station and control method

A communication apparatus includes a memory, and a processor coupled to the memory and configured to receive a first reception signal and a second reception signal in a first period, calculate a first phase rotation quantity between the first reception signal and the second reception signal, receive a third reception signal and a fourth reception signal in a second period, calculate a second phase rotation quantity between the third reception signal and the fourth reception signal, determine whether to compensate for a frequency offset of a fifth reception signal based on a difference between the first phase rotation quantity and the second phase rotation quantity, and when it is determined to compensate for the frequency offset of the fifth reception signal, compensate for the frequency offset of the fifth reception signal.

Communication apparatus, communication method and communication system

A processor performs a process that includes decoding, from among a radio signal received by the radio signal receiving apparatus, control data that includes information indicating frequency bands that a mobile station apparatus is capable of dealing with, component carriers and scenarios for carrier aggregation, receiving the decoded control data, calculating, in accordance with the received control data, a transmission-bandwidth adjacency level value indicating a policy on component-carrier allocation to the mobile station apparatus, determining, in accordance with the calculated transmission-bandwidth adjacency level value, a component carrier to be allocated to the mobile station apparatus from among the component carriers and the frequency bands that the mobile station apparatus is capable of dealing with; and generating a transmission signal that includes information indicating the determined component carrier.

Base station apparatus, radio communication system, and radio communication controlling method

A terminal apparatus includes a downlink transceiver that receives downlink data via a base station governing a first cell and exchanges with the base station governing the first cell, control information that is for receiving the downlink data; and an uplink transceiver that transmits uplink data via a base station governing a second cell that is different from the first cell and exchanges with the base station governing the second cell, control information that is for transmitting the uplink data.

Terminal apparatus, communication system, and communication method

A baseband receiving unit receives a signal transmitted from a wireless communication terminal device and including a plurality of symbols arranged in a time direction. A scheduling unit estimates the frequency offset based on a first signal that is for measuring quality and that is mapped to a first symbol placed at a predetermined position in the transmitted signals received with the baseband receiving unit, and a second signal that is for demodulation and that is mapped to a second symbol placed at a position different from the first symbol in the transmitted signal.

Base station apparatus, wireless communication system, wireless communication terminal device, and method for controlling wireless communication system

A base station apparatus includes an area setting module that sets a part of an area of resources used for communication with a radio communication terminal devices as a search area, a plurality of selecting modules that each select a resource included in the search area and belonging to a group allocated to the scheduler of each of the selecting modules out of groups divided based on logical positions of resources, and an L1 function module that transmits a signal including control information by using the resource selected. The radio communication terminal device includes an acquiring module that receives the signal and searches the search area in the received signal to acquire control information addressed to the radio communication terminal device, and a communication module that communicates with the radio base station based on the control information acquired.

Radio communications system, radio base station apparatus, and method for controlling radio communications system

A communication apparatus including: a receiver to receive signals including reference signals at each of a plurality of different reception intervals; and a processor to estimate phase differences between the signals based on the reference signals, to determine a plurality of phase difference candidates for each of the reception intervals based on the phase differences, to select, from among a plurality of combinations of the phase difference candidates for the reception intervals, a combination of the phase difference candidates between the signals, and to estimate a frequency deviation of the signals based on the phase difference candidates included in the combination.

Communication apparatus and communication method

A reception apparatus used by a Code Division Multiple Access (CDMA) system base station includes a path detection unit performing path detection on a selected user equipment. Also included is a deriving unit using the detected path timing to despread incoming signals from said selected user equipment and deriving one or more multipath components. Also included is a providing unit Rake combining said one or more multipath components to provide a demodulation signal. Also included is a scheduling unit selecting one or more user equipments at predetermined intervals according to one or more judgment criteria and reporting to the path detection unit. The one or more judgment criteria includes criteria for selecting the user equipment with the demodulation signal which has a higher fading frequency.

Reception apparatus, path detection apparatus, method thereof, and computer product used in CDMA system base station

A receiving apparatus includes a memory that stores parameters corresponding to lines based on a first time interval and a second time interval in a coordinate space in which first phase rotation in a reception signal is defined as a first axis and second phase rotation in a reception signal is defined as a second axis; a selecting device that selects a line that is closest to a coordinate point in the solution space, the coordinate point being represented by a first observation value of the first phase rotation and a second observation value of the second phase rotation; an acquiring device that acquires the parameters corresponding to the line from the memory; and an estimating device that estimates, based on the parameters, the first observation value, and the first time interval or the parameters, the second observation value, and the second time interval, frequency deviations of the reception signals.

Receiving apparatus, frequency deviation calculating method, and medium storing computer program therein

In a wireless communication system including a wireless terminal, a first wireless base station, a second wireless base station which supports a wireless channel which is not supported by the first wireless base station and an upper level apparatus which accommodates the wireless base stations, the upper level apparatus monitors interference power in the wireless base station and carries out, where a result of the monitoring exceeds a predetermined threshold value, suppression control of transmission power of the wireless terminal which communicates with the second wireless base station using the wireless channel which is not supported by the first wireless base station.

Method for controlling an uplink power in a wireless communication system and an apparatus in the system

A base station used in a communication system wherein user terminals are classified into cell center terminals and cell edge terminals, based on reception quality and includes a receiving unit that receives cell edge band information transmitted from another base station and indicative of a cell edge band allocated to a cell edge terminal in a nearby cell; a determining unit that determines a cell edge band for a cell of the base station, based on the cell edge band information for a plurality of nearby cells and received by the receiving unit; and a communicating unit that, via the cell edge band determined by the determining unit, communicates with the cell edge terminals in the cell of the base station.

Base station, communication system, and communication method

A procedure of receiving includes estimating a phase offset of a received signal and calculating one or more phase offsets which result in the estimated phase offset of the received signal and which have different phase rotation directions and/or different phase rotation amounts from one another; compensating for the phase offset of the received signal, using each of a plurality of phase offsets that are the estimated phase offset and the calculated phase offsets, and demodulating and decoding the plurality of compensated received signals; and selecting a decoding result that is the most likely to be the received signal among a plurality of results of the decoding corresponding one for each of the plurality of phase offsets.

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Yokohama, Japan

Takato Ezaki