Hitachi, Ltd.

Hitachi-kokusai Electric Inc.

Yunjian Jia

Kenzaburo Fujishima

Takashi Yano

Hitoshi Ishida

Katsuhiko Tsunehara

Tsuyoshi Tamaki

Shigenori Hayase

Keisuke Yamamoto

Mikio Kuwahara

Masaaki Shida

Hideya Yoshiuchi

Peng Yang

Zhisheng Niu

Jie Gong

Sheng Zhou

Yuanchen Ma

Lu Geng

A base station performs an association between frequency range and combinations of a plurality of base stations including an local base station to notify a terminal of the association. According to the notified association, the terminal, for each frequency, calculates quality of communication with one base station or quality of communication with the combination of the plurality of base stations. The base station and the control station determine the base station/the plurality of base stations that communicate with the terminal, the wireless resource and the transmission scheme, based on the result. Further, the base station selects whether to notify an entirety of or a part of the association to the terminal using positional information of the terminal. Since the association information that is unnecessary for the terminal is not communicated, it is possible to further lighten the load of control.

Wireless communication system, base station, and wireless communication method

A base station broadcasts a message saying that transmittable ranging codes are limited by antenna IDs to limit antennas and the ranging codes to be searched, thereby reducing a processing load of the search. In a cellular radio communication system in which a base station device is connected to plural antennas, and antenna IDs for identifying the antennas are transmitted from the respective antennas, the base station device broadcasts a message saying that a group of ranging codes transmittable by a terminal device is limited by the antenna IDs, the terminal device receives the message, identifies the antenna ID, selects the ranging code from the group of the ranging codes corresponding to the antenna ID, and transmits the selected ranging code.

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

In an environment in which a macro base station and a low transmission power base station exist, the ratio of the interference reduction time period of the macro base station is optimized, and the throughput of the low transmission power base station is improved, while minimizing a reduction in throughput. The macro base station causes a high interference to other base stations and one or a plurality of low power nodes (LPN) subjected to interference from the macro base station. The macro base station sets first and second data transmission time periods and then determines the ratio of the second time period and the pattern of the first time period and the second time period based on communication quality in the first time period and communication quality in the second time period of the macro base station and the LPN.

Radio communication system, base station, and interference management scheme

Disclosed are a communication control device, a communication control method and the system thereof, which provide efficient multi-base station joint services in a mobile communication system using dynamic clustering. Optimal base station clustering is chosen according to the communication state between a terminal and each base station. The communication control device connects with multiple base stations through a network, and clusters the multiple base stations dynamically so that the clustered multiple base stations can provide services for the mobile terminal in union. The communication control device comprises: an interface, connecting with multiple base stations, receiving channel state information related to the mobile terminal from each base station; a memory unit, storing the channel state information of the mobile terminal received from the interface; a control unit, clustering each base station dynamically according to the channel state information of the mobile terminal stored in the memory unit.

Device and method for base stations dynamic clustering in mobile communication

A frame time having a certain period of time is divided into: a time period (for inter-base-station time division multiplex communication) in which one of the base stations has a transmission right in the simultaneous transmission and carries out inter-base-station time division multiplex communication so as to avoid interference between the base stations; and a time period (for inter-base-station simultaneous communication) for communication which is simultaneously carried out between the plurality of base stations. Furthermore, the time periods are switched for the communication.

Wireless communication system, integrated base station, and terminal

To secure a constant level or more of radio communication quality for each user equipment performing radio communication with a base station apparatus, and to increase the number of user equipment which the base station apparatus can accommodate under a condition of assuring the radio communication quality. In a radio communication system where there exist a base station apparatus having multiple antennas and user equipment for performing radio communication with a first antenna group including one or more of the antennas, the first antenna group is made configurable for each user equipment individually, and addition/deletion of the antenna to/from the first antenna group is performed based on the communication quality of each user equipment so that the number of antennas within the first antenna group may be minimized within a range satisfying a required value of the communication quality between the base station apparatus ad the user equipment.

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

A transmitting station having plural antennas includes: a control information calculation unit that calculates control information for use by plural receiving stations according to a multi-user MIMO data transmission scheme; a control information transmission parameter calculation unit that calculates a control information transmission parameter based on spatial channel related information; and a control information transmission signal creation unit that creates a control information transmission signal, using the control information transmission parameter and a pilot signal. A resource element mapping unit maps control information transmission signals onto corresponding resource elements for transmission. On the other hand, the receiving stations each include a control information acquisition unit that acquires plural pieces of control information signaled on the corresponding resource elements, acquire control information destined for each receiving station, and demodulate received signals.

Radio communication system, radio communication device, and radio communication method

In the case where a base station other than of a distributed antenna system provides a time or frequency at which a transmitted power is low, an antenna group configuration unit estimates a communication area of a mobile station using an uplink reference signal that the mobile station transmits, calculates an inter-system interference power for the communication area of each mobile station based on a received power of the out-of-system base station that the each mobile station reports, calculates the inter-system interference power to each of antennas by averaging the inter-system interference powers that the multiple mobile stations report, and decides antennas that form an antenna group according to magnitudes of the calculated inter-system interference powers.

Distributed antenna system, allocation of distributed antennas, base station

The error correction capability for wireless communication carried out involving propagation path fluctuation in time and frequency selectivity can be improved. A soft decision likelihood value inputted to an error correction decoder is multiplied by a weight determined according to the distance between the data symbol and pilot symbol corresponding to the soft decision likelihood value. Namely, the soft decision bit likelihood value corresponding to the data symbol is weighted according to the distances in time or frequency between the pilot symbol and data symbol. The weight is made smaller when the distance in time or frequency is larger.

Wireless communication system, receiver and signal processing method for received signal

A wireless communication equipment includes receive processing and transmit processing. The receive processing includes a Fourier transform unit that transforms all received signals to frequency region signals by Fourier transform. A demodulation unit demodulates the received signals from the Fourier-transformed frequency region signals. A random access detection unit that monitors signals in frequency regions of random access signals of the Fourier-transformed frequency region signals, and detects that the random access signals are received, by a change pattern of the signals in the frequency regions of random access signals in one transmission time interval.

Wireless communications equipments with function of detecting random access signal, wireless communications systems with function of detecting random access signal and method of random access signal detection

A method for suppressing the peak-to-average power ratio (PAPR) while limiting deterioration in signal characteristics in wireless communication devices utilizing wireless communication methods (OFDM method, MIMO method) for multiplexing and sending multiple signals. A weight calculator unit sets a large weight for transmit signals whose channel quality is poor, relative to the weight of each base component based on the acquired channel quality. A peak detector unit detects the peak from the signal string after unitary conversion, and extracts a distortion component to apply for suppressing the peak. A peak suppression signal generation unit calculates the peak signal from the distortion component and weight of each base component, to add to each base component, and adds the peak suppression signal to each base component prior to unitary transformation.

Growing community of inventors

Yokohama, Japan

Yunjian Jia