Mitsubishi Electric Corporation

Sumco Corporation

Takashi Nishitani

Hiroaki Mukai

Masaki Tanaka

Hiroshi Nishimoto

Kenichi Nakura

Seiji Kozaki

Eisuke Haraguchi

Yukio Hirano

Ryuichi Tanimoto

Akihiro Tsuji

A wafer polishing method of applying mirror polishing to a surface of a wafer using a wafer polishing apparatus provided with a multi-zone pressurizing polishing head having a wafer pressing surface divided into a plurality of pressure zones and capable of performing pressurizing control independently for each pressure zone is provided with a measurement step of measuring a nanotopography map on the wafer surface; and a polishing step of performing the polishing by setting the polishing pressure of the polishing head against the wafer for each pressure zone based on a result of the measurement of the nanotopography map.

Wafer polishing method

An optical line terminal (OLT) for an optical network configured to communicate with optical network units (ONUs) in a PON-type optical network, the OLT including: a processing circuitry, for each ONUs, to manage a transmission delay time in transmission to the ONU to manage an acceptable waiting time of uplink data of the ONU; to obtain an uplink transmission start time and data amount of the optical network unit, based on uplink assignment information; and to generate uplink transmission grant information, which is made up of a time point and time length of uplink transmission to the ONU, wherein the processing circuitry determines the uplink transmission grant information on transmission to the ONU, based on a transmission delay time of the ONU, on the uplink transmission start time and data amount of the ONU, and on the acceptable waiting time of uplink data of the ONU.

Optical line terminal of optical network and uplink scheduling method

A base station apparatus includes a ground station device and a plurality of ground antenna devices coupled to the ground station device via an optical transmission path. The ground station device performs electrical-optical conversion on an analog electrical signal to be transmitted to a mobile station and a reference clock signal to generate optical signals, performs wavelength division multiplexing on the obtained optical signals to generate a multiplexed optical signal, and outputs the multiplexed optical signal to the optical transmission path. Each of the plurality of ground antenna devices demultiplexes the multiplexed optical signal input from the optical transmission path into demultiplexed optical signals, performs optical-electrical conversion on the demultiplexed optical signals to generate electrical signals, up-converts a frequency of the analog electrical signal obtained through the optical-electrical conversion based on the reference clock signal obtained through the optical-electrical conversion to generate an up-converted signal, and transmits the up-converted signal to the mobile station.

Base station apparatus, ground station device, and ground antenna device

An ONU receiving an optical signal from an OLT including PON controllers includes: an optical receiver to convert, into an electric signal, an optical signal having a single optical wavelength set out of plural optical wavelengths; and a control frame extractor to extract and hold wavelength correspondence information indicating correspondence between MAC addresses of the PON controllers received from the OLT and the optical wavelengths. The control frame extractor, when receiving a wavelength switching request, extracts the optical wavelength after wavelength switching instructed in the wavelength switching request, obtains a setting address of the MAC address of the PON controller to which the ONU itself should be connected after the wavelength switching based on the extracted optical wavelength after the wavelength switching and the wavelength correspondence information, and determines whether a malfunction occurs based on a transmission source MAC address stored in a received control frame and the setting address.

Slave station device, master station device, optical communication system, and malfunction detection method

An ONU communicates with an OLT that can transmit optical signals having different wavelengths simultaneously and receive optical signals having different wavelengths simultaneously. The ONU includes: an optical transceiver that receives any one of the optical signals that the OLT can transmit and transmits any one of the optical signals that the OLT can receive; a communication failure detection unit that detects a communication failure between the OLT and the ONU; and a wavelength selection unit that, when the communication failure detection unit detects a communication failure, changes a setting of a downstream wavelength to be received by the optical transceiver and an upstream wavelength to be transmitted by the optical transceiver.

Slave station apparatus, master station apparatus, control device, communication system, and wavelength switching method

A bandwidth control method used in a case where, for example, a first communication device (OLT) allocates a bandwidth for signal transmission to each of a plurality of second communication devices (ONUs) connected to the OLT in a communication system having the OLT and the ONUs includes a sleep controlling of shifting devices among the ONUs that satisfy a predetermined condition into a power saving state, a control-target selecting of selecting control target devices among the ONUs based on a result of performing the sleep controlling, and a bandwidth determining of determining a bandwidth to be allocated to the selected control target devices.

Bandwidth control method, communication system, and communication device

A communication device operating as a master unit includes: a MAC layer termination functioning unit for extracting, from a receiving signal, queue length information scheduled to be transmitted from an ONU, and controlling transmission of a grant to the ONU; a traffic monitor for measuring an amount of uplink traffic of each ONU; and a bandwidth allocation functioning unit for determining a bandwidth to be allocated to each ONU based on the queue length information extracted by the MAC layer termination functioning unit, the amount of traffic measured by the traffic monitor, and a bandwidth that can be allocated in one cycle of bandwidth update, and issuing a grant according to the determination. The bandwidth allocation functioning unit updates a bandwidth to be allocated periodically.

Growing community of inventors

Tokyo, Japan

Takashi Nishitani