Nec Corporation

Masato Shiokawa

Hiromi Honma

Kunifusa Maruyama

A channel estimation device comprises: a channel variation detection unit that determines whether variation width of a received signal level is not less than preset threshold width and whether variation period of received signal is not greater than preset threshold period; and a channel estimation unit that, if the channel variation detection unit determines that the variation width of the received signal level is not less than preset threshold width and that variation period is not greater than preset threshold period, refers to hysteresis of received signal level to determine whether lowering of received signal level is temporal, and, if it is determined that lowering of received signal level is temporal, allowing received signal to pass through, without removing received signal as noise, even when received signal level is not greater than signal level to be removed as noise.

Channel estimation apparatus, channel estimation method and program

A base station creates a dummy pattern added with an error correction code, during occurring of a control channel not allocated for transmission of control information, transmits the dummy pattern instead of control information at a power level lower than a normal power level. A mobile station decodes control information transmitted through the control channel, examines whether or not a value specified by the decoded control information is within a suitable range, and performs error detection of the decoded control information. The mobile station stops decoding of data transmitted through a data channel, upon judging that the value is not within the suitable range or detecting an error in the error detection.

Radio communication system

A mobile communication system including a base station which divides a transmission frequency band into a plurality of frequency blocks, and assigns radio resources to each mobile station for each of the frequency blocks, the base station including: a frequency block assignment information creation portion that creates frequency block assignment information based on a downlink signal reception status and a downlink signal reception status degradation rate in each mobile station; and a radio resource assignment portion that assigns the radio resources to each frequency block based on the frequency block assignment information.

Mobile communication system and radio resources assigning method for the system, and base station

A PRML (Partial Response Maximum Likelihood) signal processing apparatus for both MP (Mark Position) recorded medium and ME (Mark Edge) recorded medium. The apparatus has a PR (Partial Response) equalizer to which the reproduction signal from the medium is inputted, a folded back value calculation circuit for folding back an input signal thereto with a predetermined level, and a Viterbi detector having a path memory and performing a Viterbi detection. The path memory is constructed based on a structure of a trellis for a signal recorded by the MP recording. In case of the MP recorded medium, the equalizer transfer characteristics and the reference amplitude both for the MP recording are set to the PR equalizer and the Viterbi detector, respectively, and the output of the PR equalizer is directly supplied to the Viterbi detector. On the other hand, in case of the MP recorded medium, the equalizer transfer characteristics and the reference amplitude both for the ME recording are set, and the output of the PR equalizer is supplied to the Viterbi detector via the folded back value calculation circuit.

Partial response maximum likelihood (PRML) signal processing apparatus

In a signal processor for processing a multilevel signal, a partial response equalizer is provided having a first predetermined number of reference amplitudes. The equalizer receives the multilevel signal and detects a significant instant of amplitude transition of the multilevel signal with respect to the reference amplitudes and produces a signal representative of the amplitude at the detected significant instant. The amplitude representative signal assumes one of a second predetermined number of amplitudes including spontaneously generated amplitudes, the second predetermined number being greater than the first predetermined number of the reference amplitudes. A maximum likelihood estimator, connected to the equalizer, have transition states and a state transition rule which determines one of the states with respect to decision thresholds greater in number than the first predetermined number and equal to or smaller than the second predetermined number. The estimator receives the amplitude representative signal from the equalizer and perform maximum likelihood estimation on the equalizer output according to the state transition rule.

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Tokyo, Japan

Masato Shiokawa