Ntt Docomo, Inc.

Osamu Nakamura

Shinji Uebayashi

Takayuki Ishiguro

Rie Nagato

Naoto Shimada

Takanori Utano

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

A base station comprises: an interference quantity measurement unit configured to measure an interference quantity toward a frequency band used in a communication system in which the base station is provided; an allowable interference quantity calculation unit configured to calculate an allowable interference quantity toward the frequency band, which is allowed to maintain a determined number of terminal equipments connecting lines with the base station, based on the measured interference quantity and the determined number of the terminal equipments; a reception unit configured to receive a request of connecting the line transmitted by the terminal equipment; and an acceptance control unit configured to control an acceptance of the request for connecting the line by comparing the measured interference quantity with the allowable interference quantity.

Base station and communication method

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 mobile communication system is provided that employs a data communication control method that includes a radio control apparatus that communicates with a mobile station that performs VOX control using a first frequency band area and a second frequency band area. Receiving a request for data transmission to the mobile station, the radio control apparatus determines whether radio wave transmission and reception are being performed with the mobile station in a communication operation using the first frequency band area. The radio control apparatus then determines a transmission time for data transmission in a communication operation using the second frequency band area, based on a communication pattern of the mobile station that is a data transmission destination designated by the request for data transmission. If radio wave transmission and reception are not being performed in the communication operation using the first frequency band area, the radio control apparatus transmits the requested data to the data transmission destination mobile station within the determined transmission time.

Radio control apparatus, data communication control method, and mobile communication system

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

In the case where two wireless communication systems are located close to each other and possibly interfere with each other, it is detected if broad band interference takes place, and, when broad band interference takes place, the use of frequencies is limited within such a frequency range in which the wireless communication systems are little affected by the interference. An interference detection system for detecting interference between one system and another system in a wireless communication making use of frequency division multiplexing is described. The interference detection system includes a radio frequency signal receiving unit; a signal level storing unit; a calculation result storing unit; a threshold level comparing unit; and a carrier number storing unit.

Interference detection method and interference avoidance system for wireless communication links

A simplified interference elimination system is provided for eliminating from a first radio signal transmitted from a first radio terminal to a first radio base station, the effect of interference due to a second radio signal transmitted from a second radio terminal to a second radio base station. The second radio base station has an extractor for extracting the second radio signal from radio signals received in the second radio base station, and a transmitter for transmitting the extracted second radio signal to the first radio base station. The first radio base station has an interference eliminator for eliminating the second radio signal transmitted from the second radio base station from radio signals received in the first radio base station.

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Yokosuka, Japan

Osamu Nakamura