NTT DoCoMo

About: NTT DoCoMo is a based out in . It is known for research contribution in the topics: Base station & Mobile station. The organization has 4032 authors who have published 8655 publications receiving 160533 citations.

Signal format in multi-carrier cdma transmission system

Abstract: A multi-carrier CDMA transmission system for performing information multiplex transmission by copying information symbols and arranging them on a frequency axis, multiplying the copied information symbols by diffusion codes on the frequency axis, and using a plurality of sub-carriers having different frequencies, wherein, in a signal format of a transmission signal used when a pilot symbol for estimating variations in a transmission line is inserted for performing synchronous detection, the above pilot symbol consists of a signal format containing a common pilot symbol for estimating a transmission line common to respective users and user-specific individual pilot symbols used for communication on transmission lines different from the above transmission line.

Transmitter, receiver, mobile communication system and synchronization channel

Abstract: A transmitter includes an amplitude adjustment unit multiplying an amplitude adjustment sequence value for adjusting amplitude with a synchronization channel transmitted from a base station for establishing synchronization with a mobile station.

Power series predistorter and control method thereof

Abstract: In a distortion generation path of a power series predistorter, a frequency characteristic compensator that adjusts the frequency characteristic of a distortion component is provided in series with an odd-order distortion generator. The output of a power amplifier is divided to obtain an output signal of the power amplifier, the output signal of the power amplifier is down-converted by a down converter, and a distortion detector detects a distortion component in the down-converted signal of base band. The frequency characteristic of the distortion component is split into windows each having a band width of Δf by a distortion component frequency characteristic splitter, and the power of the distortion component in each window is detected. Based on the detected power, the frequency characteristic compensator adjusts a part of the frequency characteristic of the distortion component associated with each window.

Signal power dynamic range compressing circuit and power amplifier using the same

Abstract: In an input signal power dynamic range compressing circuit, an input signal is distributed by a directional coupler to a linear signal transfer path and a compressing signal generating path, and in the compressing signal generating path a compressing signal, which keeps the peak-to-average-power ratio of the input signal below a predetermined value, is generated from the input signal. The compressing signal is combined by a power combiner with the input signal having passed through the linear signal transfer path.

Positioning System and Positioning Method

Abstract: It is an object of the present invention to perform positioning at favorable positioning precision and in a favorable positioning time, according to whether a receiver is indoors or outdoors. A positioning server 10 comprises a reception state information acquisition component 12 that acquires reception state information indicating the reception state of a radio wave at a cellular terminal 20, a base station positioning calculator 13 that estimates the position of the cellular terminal 20 on the basis of the reception state information, an end decision component 14 that decides whether or not to end the position estimation on the basis of a specific end condition, and, if it is decided not to end, estimates the position of the cellular terminal 20 on the basis of new reception state information, an indoor/outdoor determination component 15 that determines whether the cellular terminal 20 is indoors or outdoors on the basis of the reception state information, and an end condition determination component 16 that determines the specific end condition on the basis of a result of determination by the indoor/outdoor determination component 15.