Ntt Docomo, Inc.

Ntt Mobile Communications Network, Inc.

Nippon Telegraph and Telephone Corporation

Shinji Uebayashi

Osamu Nakamura

Seizo Onoe

Takayuki Ishiguro

Mamoru Sawahashi

Takehiro Nakamura

Minami Ishii

Tamami Maruyama

Ryo Yamaguchi

Tatsuo Furuno

Yukihiko Okumura

Motohiro Tanno

Katsumi Kobayashi

Ichiro Okajima

Toshio Nojima

Akihiro Maebara

Koji Ohno

Toshiyuki Futakata

Yoshiaki Tarusawa

Koichi Okawa

Rie Nagato

Noriko Uchida

Teruo Onishi

Takanori Utano

Takahiro Iyama

Hui Zhao

Narumi Umeda

Fumiyuki Adachi

Kouji Ohno

Toshio Miki

Masami Yabusaki

Tadao Nagatsuma

Tomoyuki Ohya

Etsuhiro Nakano

Tomohiro Dohi

Hiroyoshi Togo

Kunio Sawaya

Qiang Chen

Naoto Shimada

Qiaowei Yuan

Katsuki Kiminami

Naofumi Shimizu

Seizou Onoe

Kouji Yamamoto

Shin Nakamatsu

Long Li

Azusa Wada

Kouichi Sawai

Junichirou Hagiwara

A radio communication system according to the present invention includes a scatterer configured to reflect, refract, or transmit a radio wave radiated primarily from a transmission side apparatus to radiate the radio wave secondarily to a desired area and a metamaterial is used for the scatterer.

Radio communication system

A reflect array () according to the present invention includes a plurality of array elements () forming an array configured to control a direction of a reflected wave (scattered wave) by controlling a phase of the reflected wave; and a ground plane (). The ground plane () has a structure with a frequency selective function.

Reflect array

The present invention relates to a radio communication system configured to secondarily-radiate, to a desired area by reflection, primarily-radiated radio waves from a transmitter apparatus, by using a reflector plate for controlling phases of reflected waves, wherein a reflecting property of the reflector plate is set so that the reflector plate reflects the primarily-radiated radio waves as plane waves of equal phase directed to a direction different from a reflection angle in the case of specular reflection.

Radio communication system, periodic structure reflector plate, and tapered mushroom structure

A weighting parameter estimation system for estimating a weight parameter for the antenna elements of a mobile terminal is provided. The system includes a prohibited space forming part to which electromagnetic waves should not be directed when the mobile terminal transmits a signal in wireless communications, and a weighting parameter determination unit configured to determine the weighting parameter for each of the antenna elements of the mobile terminal such that the power level of a test wave transmitted from or received in the prohibited space becomes the minimum.

System and method for estimating weighting parameters for antenna elements

A signal transmission method checks, when detecting an occurrence of a communication request, whether the communication request is a high speed communication (step S). In the case of the high speed communication, it checks whether the number of current high speed communications (m) plus one is greater than the upper limit (m) of the high speed communication (step S). If greater, it cancels the request as a call loss (S), and sets to a variable a the ratio (h) of the rate of the high speed communication to that of a low speed communication. If the communication request is the low speed communication, it sets one to the variable a (step S). It compares n plus a with n(step S), where n is the total number of all the current communications, a is the value associated with the communication request, and nis the upper limit of the number of communications acceptable in a bandwidth, all of which are expressed in terms of the number of the low speed communications. If n plus a is greater than n, the communication request is canceled as a call loss (S). Otherwise, the total number of the current high speed communications (m) and the total number of all the current communications (n) expressed in terms of the number of the low speed communications are updated, and a channel is assigned to the communication request (step S).

Signal transmission method and base station in mobile communication

A radio terminal () and a radio relay () perform radio communications therebetween by a radio communications system else than a TDMA system, an interference measurer () measures a degree of interference of each of radio slots constituting a radio channel employed in the radio communications system, a decision maker () makes a decision, depending on a measurement result of the degree of interference, whether or not the radio communications by the radio communications system is able to be continued, and a switcher () switches, as the decision is made of the radio communications by the radio communications system to be unable to be continued, the radio communications system to a radio communications system of the TDMA system.

Radio communications system, radio communications method, radio relay, and radio terminal

In an apparatus for measuring absorbed power including an electromagnetic field probefixedly mounted within a head simulation phantomwhich simulates the configuration and the electromagnetic characteristics of a head of a human body, and wherein the strength of an electric field or a magnetic field of a radio wave externally irradiated upon the head simulation phantomis measured by the electromagnetic field probe, and the power of the radio wave absorbed by the head is estimated on the basis of measured values, the head simulation phantomcomprises a solid dielectric' which simulates the configuration and the electromagnetic characteristics of a head of a human body or a liquid dielectricwhich simulates the electromagnetic characteristics of a head of a human body and which is filled in an enclosed vesselwhich simulates the configuration of a head of a human body. The volume of the solid dielectric&#x2032; or the volume of the enclosed vesselis equal to or less than 5&#xd7;10mm.

Apparatus for measuring absorbed power

A specific absorption rate measuring apparatus including a probe configured to measure, in a two-dimensional plane, the amplitude and the phase of an electric or magnetic field generated in a phantom of which electrical properties similar to a human body tissues; an electric and/or magnetic field estimation unit configured to estimate a three-dimensional electric field distribution to be produced from a wave source defined by the two-dimensional electric and magnetic fields at a measuring point, based on the measurement results of the probe; and a specific absorption rate estimation unit configured to estimate a three-dimensional distribution of specific absorption rate based on the estimation result of the electric field estimation unit.

Measurement system of specific absorption rate

A biological tissue equivalent phantom unit to be used by the specific absorption rate measuring system for evaluating absorption of electromagnetic wave energy includes a biological tissue equivalent phantom for absorbing an electromagnetic wave. In addition, two or more electro-optical crystals are arranged at two or more measurement points in the biological tissue equivalent phantom. The electro-optical crystals have a dielectric constant that is approximately equal to that of the biological tissue equivalent phantom. Two or more optical fibers are laid in the biological tissue equivalent phantom for optically connecting each of the electro-optical crystals to an external destination.

Specific absorption rate measuring system, and a method thereof

A signal transmission method and apparatus over a forward traffic channel in cellular mobile communications that can simultaneously perform one or more high speed communications whose transmission rates are higher than or equal to a predetermined rate, and one or more low speed communications whose transmission rates are lower than the predetermined rate between a plurality of mobile stations and a base station.

A weight determining apparatus is disclosed. The weight determining apparatus includes two or more antenna elements that receive a test wave transmitted by one or more test wave sources prepared outside of a phantom that simulates an object that attenuates a radio wave, the antenna elements being prepared in a mobile terminal. The weight determining apparatus further includes a weight determining unit that determines weights for the antenna elements such that a signal received by the antenna elements as a whole may be maximized.

Weight determining apparatus, a weight determination method, a radiation power measuring apparatus, and a radiation power measuring method

A mobile station receives a signal based on a TDD method by receiving a signal based on a FDD method to acquire information of the signal based on the TDD method in a mobile communication system. For instance, the mobile station receives a signal based on a CDMA-FDD method. Then, the mobile station acquires information (e.g. information relating to a code, a frequency and a timing) of a signal based on a CDMA-TDD method from the signal based on the CDMA-FDD method. Then, the mobile station receives the signal based on the CDMA-TDD method on the basis of the acquired information.

Mobile station, base station and communication method

In an apparatus for measuring absorbed power including an electromagnetic field probefixedly mounted within a head simulation phantomwhich simulates the configuration and the electromagnetic characteristics of a head of a human body, and wherein the strength of an electric field or a magnetic field of a radio wave externally irradiated upon the head simulation phantomis measured by the electromagnetic field probeand the power of the radio wave absorbed by the head is estimated on the basis of measured values, the head simulation phantomcomprises a solid dielectric' which simulates the configuration and the electromagnetic characteristics of a head of a human body or a liquid dielectricwhich simulates the electromagnetic characteristics of a head of a human body and which is filled in an enclosed vesselwhich simulates the configuration of a head of a human body. The volume of the solid dielectric&#x2032; or the volume of the enclosed vesselis equal to or less than 5&#xd7;10mm.

Absorption power measuring device

In a communication channel set up method, the utilization state of a prescribed frequency in the first frequency band that causes interferences to the first communication system when the communication channel of a particular frequency in the second frequency band is used at the second communication system is detected, and if the prescribed frequency in the first frequency band is currently used, the communication channel other than that of the particular frequency is allocated to the second communication system.

Communication channel set up method and communication control device for reducing interferences between radio communication systems

A communication channel allocation method allocates a communication channel to communications between a mobile terminal device and a second radio base station using a second frequency band which is close to a first frequency band used by a first radio base station, by detecting a first distance between the second radio base station and the first radio base station, detecting a second distance between the second radio base station and the mobile terminal device when the first distance is less than a first threshold, and allocating a communication channel of a frequency far from the first frequency band in the second frequency band to the communications between the second radio base station and the mobile terminal device when the second distance is less than a second threshold.

Radio communication system for reducing interferences with respect to other communication system using close frequency band

Growing community of inventors

Yokohama, Japan

Shinji Uebayashi