Hitachi, Ltd.

Hitoshi Ishida

Kenzaburo Fujishima

Yunjian Jia

Tsuyoshi Tamaki

Rintaro Katayama

Hiroshi Kanai

Seiichi Hayashi

Kazuo Kikuchi

Yousuke Nagano

Masayoshi Sunada

Takeo Sonobe

Junichi Enomoto

Kazuei Saito

Yasumasa Saito

Toshiaki Suematsu

Tetsuro Hatakeyama

Shinji Mizunuma

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

To reduce an uplink interference in a network with a first base station of a large output and a second base station of a small output. Detecting the interference, the second base station urges the first base station to hand over a terminal causing it to the second base station. Multiple base stations and one or more terminals exist in this system, each terminal connects with one base station, and a serving base station is changed according to a communication state of each terminal. If the different second base station other than the first base station to which the terminal connects detects a large interference, the second base station will multicast transmit information for urging handover to the base stations except itself. The base station having received the information specifies a terminal giving the interference to the second base station, and makes it to be handed over thereto.

Wireless communication system and base station

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

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

An alignment disk having an adjust signal recorded thereon to maintain data interchangeability of a magnetic disk drive apparatus and loadable and unloadable to and from the magnetic disk drive apparatus, and method and apparatus for verifying a tracking errors of the magnetic disk drive apparatus are disclosed; the magnetic disk drive apparatus including magnetic head means for recording and reproducing data on and from a magnetic recording medium, a head carriage for carrying the magnetic head means, and drive means for driving the head carriage radially of a track of the magnetic recording medium; the alignment disk having a set of track diameter adjust signal pairs recorded on tracks equal to or larger in number than the number of phases of a stepping motor for driving the head carriage and corresponding to at least the excitation phases of the stepping motor; the set of track diameter adjust signal pairs each having an inner track signal and an outer track signal extending inward and outward from a center of the track; and the set of track diameter adjust signal pairs being arranged symmetrically about a rotation axis of the disk.

Alignment disk for magnetic disk driving apparatus and method and

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Fujisawa, Japan

Hitoshi Ishida