Hitachi, Ltd.

Nec Corporation

Hitachi Astemo Ltd.

Hitachi Communication Technologies, Ltd.

Tsinghua University

Sony Computer Entertainment Inc.

Godo Kaisha IP Bridge 1

Satoshi Tamaki

Takashi Yano

Seishi Hanaoka

Tomonori Yamamoto

Rintaro Katayama

Toshiyuki Saito

Hirotake Ishii

Mikio Kuwahara

Takeshi Kato

Koki Uwano

Katsuhiko Tsunehara

May Takada

Kenzaburo Fujishima

Tsuyoshi Tamaki

Lei Li

Shinya Sasaki

Shigenori Hayase

Zhisheng Niu

Hajime Kanzaki

Koichiro Furueda

Go Ono

Ryouichi Tanaka

Fumiteru Sato

Shigeyuki Ejiri

Moemi Fujio

Pinai Linwong

Takuji Kawahatsu

Shiro Tanabe

Akira Sato

Keima Yamada

Naomi Yonezawa

In a wireless communication device, which is mounted on a vehicle and performs wireless communication with a wireless communication device as a communication target using a plurality of frequency channels, the plurality of frequency channels includes a first channel and a second channel, and the first channel uses at least a radio signal of a polarization plane orthogonal to a polarization plane of a radio signal in the second channel.

Wireless communication device, communication control method, and wireless communication system

The present invention provides a wireless communication system capable of performing communication between wireless communication apparatuses respectively mounted on vehicles performing platooning is characterized in that a frequency channel used in data transmission and reception between an own vehicle and a preceding vehicle adjacent to the own vehicle, and a frequency channel used in data transmission and reception between the own vehicle and a succeeding vehicle adjacent to the own vehicle are different from each other.

Wireless communication system and wireless communication apparatus

Communication quality such as a delay time is stabilized when a plurality of communication devices on the same mobile object simultaneously perform communication. A wireless communication system that is mounted on a mobile object is a wireless communication system including a first communication device and a second communication device that are mounted on a first mobile object. When information is shared by mobile objects by transmitting packets based on information acquired from a network within the first mobile object to a communication device mounted on a second mobile object, the first communication device and the second communication device transmit packets having the same content by adopting the same communication method and using different channels, and a signal transmission timing from the second communication device is set to be later than a transmission timing from a communication device from the first communication device.

Wireless communication system, wireless station, and mobile object information sharing method

Interference applied to neighbor cells during terminal handovers can be reduced in wireless communication systems containing base stations having different cell sizes. A serving cell makes handover judgment criteria easier based on pre-acquired cell size information on its own cell and cell size information of neighbor cells in order to facilitate terminal handovers from a base station with a large cell size to a base station with a small cell size. The serving cell finds evaluation function values based on the propagation state (e.g. reference signal received power) between the terminal and target cell, and the interference and load information exchanged between the base stations, and selects the terminal for handover by comparing the evaluation function value with the handover criteria value. The system selects a target cell having a good effect in lowering interference such as a cell with large reference signal received power acquired from a terminal, to serve as the handover destination.

Mobility control method mitigating inter cell interference and base stations which adopt the method

A radio communication system using an orthogonal frequency division multiplexing system, including: a baseband unit; and one or plural remote radio units coupled with the baseband unit through an interface; wherein the baseband unit includes a first sample frequency conversion part that performs a first sample frequency conversion processing that down-samples a transmitting signal transmitted through the interface, wherein the remote radio unit includes a second sample frequency conversion part that performs a second sample frequency conversion processing that up-samples a signal received through the interface, and wherein the baseband unit further includes an inverse fast fourier transform part that generates the transmitting signal by an inverse fast fourier transform, and a transmitter characteristic compensation part that conducts frequency characteristic compensation of the first sample frequency conversion processing and the second sample frequency conversion processing for a signal that has not been subjected to the inverse fast fourier transform.

Transmitting device, receiving device, and signal processing method in radio communication system

This invention provides a mobile communication system which expanded the operation limitation of the heretofore adopted mobile communication systems and improved the spectrum efficiency greatly. A data transmission method for use in the mobile communication system of the present invention includes means for channel pluralizing by which to expand the Shannon limit and means for interference reduction by which to expand the interference limit. More specifically, a transmitting module comprises M units of modulators and L units of transmitting antennas, generates L units of signals by multiplying M units of modulated signals by a complex matrix consisting of M&#xd7;L units of elements, and transmits the L units of signals from the L units of transmitting antennas.

Data transmission method for a mobile communication system

Transmission power relative to a propagation path having a variation in gain is controlled to increase communication channel capacity, and a data rate is controlled in accordance with the variation of the increased communication channel capacity. In order to increase the communication channel capacity, the transmission power is determined so that the sum of noise power (=received noise power/propagation path gain) converted into one at a transmitter and the transmission power becomes constant. As a result, contrary to the background art, the transmission power is controlled to be reduced when the propagation path gain decreases and to be increased when the propagation path gain increases.

Transmission power control method for a wireless communication system

A discontinuous change in a transmission timing in a time domain, which is caused by a transmission timing adjustment processing of an OFDMA uplink or the like, brings about a discontinuous rotation of a signal phase in a frequency domain, resulting in reduced communication quality. A wireless communication system of the present invention allows the signal phase of the frequency domain in a receiving station to be continuous before and after the timing adjustment processings by controlling a signal sequence in a transmission signal after conversion in the time domain in synchronization with the timing adjustment processing.

Timing adjustment method, receiving station, and transmitting station in wireless communication system, and wireless communication system

A cellular radio communication system includes a first mobile terminal, a base station that performs radio communication with first mobile terminals, a second mobile terminal, and a second base station that performs radio communication with second mobile terminals. In the downlink communication, the base station selects a high data rate mode when the radio interference from the base station to the second mobile terminals that are located close to an edge of a communication area of the second base station is small. The base station selects an interference mitigation mode in the downlink communication when the radio interference from the base station to the second mobile terminals that are located close to the edge of the communication area of the second base station is large. Thus, inter-cell interference control can be performed in collaboration with base stations in the radio communication system without having communication interface between the base stations.

Base station

In a time slot in which a first base station for performing a multicast transmission executes the multicast transmission, a second base station which does not perform the multicast transmission does not perform a unicast data transmission. The time slot in which the first base station performs the multicast transmission is notified to the second base station from a multicast control apparatus for performing scheduling of the multicast transmission to the first base station. Information to receive the multicast transmission is notified from the second base station to a terminal connected to the second base station.

Wireless communication system, base station and network control apparatus

Ameliorate deterioration in quality of communication caused by intercell interference with respect to a multicarrier communications protocol, such as OFDM. A method of positioning an error correction-coded signal is changed with a data symbol that is transmitted simultaneously with a pilot signal and a data symbol that is not simultaneous with the pilot symbol. Else, a modulation protocol is changed with a data symbol that is transmitted simultaneously with a pilot signal and a data symbol that is not simultaneous with the pilot symbol. It would further be permissible to lower either a signal amplitude or a power level of a data symbol that is transmitted simultaneously with a pilot signal.

Signal mapping method and communication device

A communication device includes pilot signal sending part and transmit power control part and holds a criterion value indicating target channel quality for mobile stations within the area covered by the base station. It creates quality data from reports from one or plural mobile stations, stores the quality data, creates a first representative value indicating average channel quality for the mobile station(s) from the stored quality data, and changes the transmit power depending on the result of comparison between the first representative value and the criterion value. It creates a second representative value indicating distribution of low channel quality from the stored quality data and updates the criterion value depending on the result of comparison between the second representative value and the criterion value.

Transmit power control method for reducing cellular interference in cellular radio communication system and radio base station device for implementing the same

Freedom for relationship between division of a signal processing unit and a pilot signal is improved in a multi-carrier communication system such as OFDM. An encoded signal is divided into resource blocks and the signals are arranged independently of the arrangement of a pilot signal. The signal arranged at the same position as the pilot signal causes a puncture upon transmission.

Encoded signal arrangement method in multi-carrier communication and communication device

Resources are assigned in units of resource blocks each composed of one or more subcarriers, inter-cell interference adjustment control information is notified to each other among base stations, a transmit power limitation on each of the resource blocks in a cell is decided based on the inter-cell interference adjustment control information; and the decision of the transmit power limitation is changed sequentially beginning at a resource block having a transmit power limitation different from the transmit power limitation on an adjacent resource block.

Growing community of inventors

Kokubunji, Japan

Satoshi Tamaki