Hitachi, Ltd.

Renesas Technology Corp.

Hirotake Ishii

Rintaro Katayama

Tomonori Yamamoto

Satoshi Tamaki

Katsuhiko Tsunehara

Takashi Yano

Takashi Ishikawa

Shigenori Hayase

Manabu Kawabe

Koichi Aratani

Satoshi Tanaka

Akio Yamamoto

Kenzaburo Fujishima

Yoshizumi Eto

Kazuaki Hori

Yukinori Akamine

Masuo Umemoto

Masanori Taira

Kazuhiko Hikasa

Yasutaka Morinaga

Hisayoshi Kajiwara

Dan Xu

Hidehiko Sawamura

To prevent the switching time influences power saving performance and packet loss prevention performance, it is provided a wireless communication base station for communicating with a terminal, comprising: a plurality of baseband signal processing units for performing baseband signal processing; a baseband allocation unit for allocating the baseband signal processing to the plurality of baseband signal processing units; and a linear processing unit for composing signals processed by the plurality of baseband signal processing units. The baseband allocation unit selects, for each data block, a baseband signal processing unit to which the baseband signal processing for the each data block is to be allocated out of the plurality of baseband signal processing units. Each of the plurality of baseband signal processing units performs the allocated baseband signal processing. The linear processing unit composes, by means of linear calculation, the signals processed by the plurality of baseband signal processing units.

Wireless communication base station and wireless communication 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

Regardless of use of small resource in donor (macro) base station, high throughput in relay femto base station is provided. The relay femto base station transfers data of a C-plane communicated between a core network and a mobile station through the donor macro base station by a radio link, and transfers data of a U-plane through an internet by a wired public line. The relay femto base station measures an interfered power from a neighboring relay femto base station, and notifies the donor macro base station of the measured interfered power, and the donor macro base station adjusts radio packet scheduling so as to prevent interference between the relay femto base stations on the basis of a notified measurement value of the interfered power.

Radio system and radio communication method

A femtocell base station collects the terminal distribution within the cell and selects terminals to represent the cell-center and the cell-edge from among the terminals within the cell. The femtocell base station also calculates maximum transmit power for the respective the cell-center and cell-edge terminals allowable by the macrocell base station. The femtocell base station sets the respective transmit power of the cell-center and the cell-edge in a range that will not exceed the maximum transmit power, adjusts the transmit power control parameter to allow control by the terminal at the power value that was set, and notifies the terminal. Communication with high throughput can in this way be attained for terminals in cells within the femtocell base station during uplink communications to the femtocell base station, and interference applied to the terminals in the macrocell base station can be suppressed.

Base station and cellular wireless communication system

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

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

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.

Resource assignment method and communication apparatus for wireless communication system

An object of the invention is to provide a wireless communication system in which the load of each cell and interference between cells are taken into account. In a handover-candidate base station and a handover-source base station, parameters for interference-reducing scheduling and handover facilitating processing are adjusted based on the mutual load information. When the handover-candidate base station, to be used for load balancing, is a large-diameter cell, transmit power control and frequency scheduling are adjusted by taking account of the load state at a cell edge. When the handover-source base station has a small-diameter cell, the number of terminals to be handed over is adjusted by taking account of the load state of the handover-candidate base station. Thus, both of interference control and load balancing are achieved.

Wireless communication system and load balancing aware handover method therefor

The base station transmits a synchronization signal that contains a pattern of repeated SYNC's generated by dividing FFT size by N wherein the pattern of repeated SYNC's is inverted in polarity for each of the SYNC's according to a code outputted from a code generating circuit. CP length is M/N of FFT size, and the number of divisions (M+N) of a symbol of the synchronization signal is brought into agreement with the code length L of Barker code. The mobile station detects the synchronization signal by using a first matched filter that has as many taps as (FFT size/N) stages, and uses a pattern of SYNC's generated by dividing FFT size by N as a tap coefficient, and a second matched filter that has as many taps as (M+N) stages and uses Barker code as a tap coefficient.

Radio base station and radio mobile station

An OFDM demodulator which does not require a reference signal for synchronization of carriers and can reduce influence of phase rotation by a propagation path when carrier synchronization is made. The OFDM demodulator performs Fourier transform plural times in 2 or more different operation ranges for the same OFDM symbol, calculates phases of sub carriers from the plural-time results of the Fourier transform, compares the calculated phases for each of the plural-time results of the Fourier transform and detects an error in frequency of reproduction carrier from the compared results.

Orthogonal frequency division multiplexing demodulator

Disclosed is the hardware construction of a radio communication apparatus that can meet advanced radio communications. A control bus for transferring control signals between a main processor and components is separated from a data bus for transferring transmission/receive signals between processor units including sub-processors and an external interface. The sub-processors constitute the processor units, and a software defined radio of the present invention may include plural processor units. The processor units are connected by a dedicated interunit interface. The processor units may include multiple sub-processors, which are connected serially through an interprocessor interface.

Radio communication apparatus with a bus dedicated to data transmission

A radio communication apparatus having a radio modem for processing a signal in a radio frequency band, a signal processor for processing a base band of a transmission or reception signal, and a CPU for processing a protocol. The signal processor includes signal processing blocks implemented by programmable software. Each of the signal processing blocks processes a signal of reception signal data input from the radio modem or from a preceding stage of one of the signal processing blocks or a signal of transmission signal data input from the CPU or from the preceding stage of signal processing block on the basis of a control signal input together with the transmission signal data or the reception signal data. The control signal can include information required by all the signal processing blocks in a common format.

Software defined radio and library configuration therefor

The invention provides a technique that saves rate conversion accompanying complicated calculations and shares an analog filter for anti-aliasing in a sampling device. The sampling device employs an anti-alias filter having a fixed cutoff frequency, an A/D converter and a D/A converter each having a clock signal input, which are capable of varying a sampling frequency, and a PLL circuit capable of varying the frequency of a clock signal; and it sets the sampling frequency not lower than an integral multiple of a signal bandwidth and double the cutoff frequency for sampling.

Software defined radio system

To simplify the configuration of functional modules in a software-defined radio apparatus, and facilitate the development of software. The functional modules have input and output terminals of a common configuration. Distributed timing control is performed so that the functional modules operate in their respective timings, and the functional modules have common input/output signals.

Software-defined radio apparatus

A wireless communication receiver that is able to lessen the effect of noise that accompanies gain change by programmable gain amplifiers. The receiver includes an AGC controller which controls the timing at which the programmable gain amplifiers make gain change, using a terminal counter and a sequencer. The receiver prevents gain change noise signals during the reception of control signals and other signals that are susceptible to noise. By the timing control feature, the programmable gain amplifiers make gain change while reducing noise impact.

Growing community of inventors

Yokohama, Japan

Hirotake Ishii