Ntt Docomo, Inc.

Satoru Fukumoto

Hitoshi Yoshino

Koji Maeda

Masashige Shirakabe

Hiroyuki Ishii

Kozue Hamamoto

A mobile communication method according to the present invention includes a step of assigning one or a plurality of Zadoff-Chu sequences to each of cells #A to #G, a step of generating a plurality of RACH preambles by performing a cyclic shift with respect to the assigned Zadoff-Chu sequences by a predetermined period Ncs in each of the cells #A to #G, and a step of acquiring the reception timing distribution of the RACH preambles in the predetermined period Ncs in each of the cells #A to #G.

Mobile communication method, mobile communication system, and radio base station

This invention relates to a frequency channel assignment system which enables adaptive overlapping use of the same frequency band in a plurality of radio communications systems. The frequency channel assignment system includes radio communications systemsandwhich use a common frequency band, and controllersand. The controllersandinclude a system characteristics information management functionconfigured to manage system characteristics information showing characteristics of frequency channels in the radio communications systemsand, and a frequency channel assignment functionconfigured to assign frequency channels to each of the radio communications systemsand, based on the system characteristics information and channel status information showing status of frequency channels, so as to avoid inter-system interference.

Frequency channel assignment system, base station, control station, inter-system common control apparatus, frequency channel assignment method, and control method

A radio frequency selection device in a radio communication system in which a radio communication channel is established between a mobile station and a base station by allocating a radio communication frequency band different from other radio communication system frequency bands is disclosed. The radio frequency selection device comprises: a frequency band determining unit that determines a radio control channel frequency band for transmitting control information, among frequency bands allocated to the radio communication system, based on the allocated radio communication channel frequency band; and a radio control channel establishing unit that establishes a radio control channel among the determined radio control channel frequency bands.

Radio frequency selection device, a radio communication system and radio control channel establishing method

A signal reception device is disclosed that is able to improve interference cancellation capabilities even when signals having different center frequencies exist on the same frequency band. The signal reception device includes an interference suppression unit to generate replicas of plural signals in the received signal and separate the signals by suppressing interference signals. The interference suppression unit includes a signal phase rotator to rotate phases of the signal candidates at preset respective rotational frequencies, the preset rotational frequencies being related to respective center frequencies of the signals in the received signal; a rotational frequency controller to set the preset rotational frequencies; and a replica generator to generate the replicas of the signals by using the phase-rotated signal candidates.

Signal reception device, signal transmission device, radio communication system, and signal reception method

A frequency selection apparatus, a mobile communications system, and a multi-band resource management method are disclosed. The frequency selection apparatus includes

Frequency selection apparatus, a mobile communications system, and a multi-band frequency resource management method

A signal separator for separating multiple signals contained in a received signal from each other based on a replica of the received signal is provided. The signal separator comprises a sampling unit configured to sample the received signal at a prescribed sampling timing; an index output unit configured to monitor sampling counts of the sampling unit and output an index signal representing a remainder of a division dividing the sampling counts by a sampling number per a prescribed time period to group the sampled signals; a coefficient-variable filter configured to generate and output a replica of the received signal based on a channel estimation value and a signal point candidate, at least one of the channel estimation value and the signal point candidate being generated according to the index signal; a subtractor configured to subtract the replica from the sampled signal and output a subtraction result as a residual signal; and a maximum likelihood sequence estimator configured to estimate a sequence for each of the multiple signals based on the residual signal, taking into account signal state transition, and output the estimation result at a signal output timing determined by the index signal.

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Yokosuka, Japan

Satoru Fukumoto