Ntt Mobile Communications Network, Inc.

Ntt Docomo, Inc.

Ntt Communications Networks, Inc.

Kiyohito Nagata

Tatsuaki Wakabayashi

Masaaki Yoshimi

Kazuhiko Kakinuma

Tadao Takami

Tomoaki Hirayama

Katsumi Kobayashi

Teruya Fujii

Kazufumi Yunoki

Akihiro Higashi

Hisashi Nakagomi

Katsunori Hamada

Among cellular radio communication systems, there are those in which a plurality of businesses, e.g. businesses A, B and C share a designated frequency band, and each business provides radio communication services using respectively allotted frequency bands. In this type of radio communication system, there are cases in which mobile stations belonging to different businesses use channels which have adjacent frequencies, in which case adjacent channel interference of a large interference level is produced. Therefore, in this radio communication system, of the frequency bands allotted to each business, the adjacent frequency bands which are adjacent to frequency bands allotted to other businesses are allotted to low power communications, while non-adjacent frequency bands which are not adjacent to frequency bands allotted to other businesses are allotted to high power communications.

Radio communication system, frequency allocation method and frequency allocation device

In CDMA mobile communication systems, there are cases in which communications are interrupted with the local base station while the mobile station is searching for channels other than the communication channel. A method is offered of preventing loss of information due to interruptions in such a case. There are a first transmission step for transmitting signals from the mobile station to the base station at a transmission rate R and a transmission output level P (when the transmission output is p in FIG. C), a suspension step of suspending signal transmissions from the mobile station to the base station (when no transmission output power as shown in the same drawing), and a second transmission step of transmitting signals from the mobile station to the base station at a transmission rate R higher than the transmission rate R and a transmission output level P higher than the transmission output level P (when 2p in the same drawing). Due to this second transmission step, it is possible to transmit information which was not transmitted during the suspension period.

Signal strength measurement method and device

A mobile communication scheme capable of notifying a communication regulation information efficiently by using radio interfaces from the macro-cell system to the micro-cell system, without requiring communications through a fixed communication network, so as to be able to regulate the service through the micro-cell system efficiently in coordination with the regulation of the service through the macro-cell system. In this mobile communication scheme, the communication regulation information is notified from the macro-cell system to the mobile station while the mobile station is located within the macro-cell system, and stored in a memory of the mobile station. Then, the communication regulation information is notified from the mobile station to the micro-cell system while the mobile station is located within the micro-cell system after moving from the macro-cell system to the micro-cell system, so that the communication regulation is applied to the mobile station at the micro-cell system according to the received communication regulation information.

Mobile communication scheme for efficiently regulating service through

Mobile communication system using base station frequency correction

Each base station measures the field intensity of downlink rediowaves from other base stations, then analyzes the received rediowaves above a predetermined field intensity value and decides whether they are rediowaves used in the same mobile radio communication system. The base station creates peripheral base station information based on information about the rediowaves decided as being used in the same mobile radio communication system.

Method for automatic creation of peripheral zone information

A mobile station measures the field intensity and bit error rate of a downlink radio wave from a base station at each measurement timing and reports the measured results to the base station. Upon receiving the measured results from each mobile station, the base station compares the measured results with a reference characteristic to determine if they are abnormal or not. The base station acquires the determined results of the measured results for a fixed period of time and statistically processes them to judge the state of interference.

Method for monitoring the state of interference by a base station of a

In the selection of a control channel of a mobile station in a radio zone to which some control channels are assigned as communication channels, the receiving levels of the control channels are sequentially measured and control channel candidates are selected. A check is made to see if a control signal can correctly be received in each of the selected control channel candidates, and if not, the number of signal reception failures in that channel is incremented by 1 in a memory used by the mobile rotation. A channel in which the number of signal reception failures has reached a predetermined value M (an integer equal to or greater than 1) is excluded from the group of control channel candidates, and the other selected control channel candidates are similarly checked to determine whether or not the reception of the control signal is possible in each of them. If the control signal can correctly be received in a given control channel, a check is made to see if the mobile station has moved into a different radio zone, and if not, the mobile station enters the state of waiting for an incoming call in that control channel. If the radio zone of the mobile station has changed, the numbers of signal reception failures in all the control channels are reset in the memory, so that all the control channels are made candidates to be selected next as a control channel of the radio zone in which the mobile station is currently located.

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Yokohama, Japan

Kiyohito Nagata