Mitsubishi Denki Kabushiki Kaisha

Nec Corporation

Kazuo Tanada

Hiroshi Kubo

Keishi Murakami

Akihiro Okazaki

Takeshi Uraguchi

A receiving device receiving a SC-FDMA signal includes a first calculating unit calculating a first channel estimation value indicating a propagation path state based on a sounding reference signal transmitted from a transmitting end device; a second calculating unit calculating a rank determination value and a modulation and coding scheme (MCS) determination value based on the first channel estimation value, the rank determination value and MCS determination value being associated with a transmission rank number and a transmission coding ratio/modulation scheme respectively, and used when the transmitting end device next transmits a data channel; a third calculating unit calculating a second channel estimation value indicating a propagation path state based on a demodulation reference signal by using interpolation processing in accordance with at least one of the rank determination value and the MCS determination value; and a demodulation/decoding unit acting on a data channel using the second channel estimation value.

Receiving device and receiving method, and computer program

A radio communication system according to the present invention comprises a transmitter having a plurality of transmission antennas, and a receiver having a mechanism to perform a diversity reception. A plurality of multi-modulators of the transmitter allocates the same transmission data to a plurality of subcarriers, combines all transmission signals obtained by weighting each of the subcarriers, and outputs combined transmission signals. At least one of weight values for the same data is different between the multi-modulators in the weighting processing for each of the carriers.

Radio communication system and transmitter

A sampling unit that sequentially samples a received signal. A plurality of demodulation processing units set in advance with frequency correction values of mutually different sizes, and that correct frequencies of the sampled signals according to the frequency correction values, demodulate the sampled signals after the frequency correction, and output decision values and reliability information of the received signal, and detect known synchronization words that have been inserted into the received signal from the decision value. A decision value selecting unit selects one final decision value from a plurality of decision values based on a plurality of pieces of reliability information that have been output from the demodulation processing units and a result of the detection of the synchronization word. And, a frequency error detecting unit estimates a frequency error of the received signal based on a frequency correction value of the demodulation processing unit corresponding to the final decision value.

Frequency error estimating receiver, and frequency error estimating method

In a sequence estimation method and a sequence estimator of the present invention, a metric is calculated using a received signal and its estimated value, also another metric is calculated using a filtering result via a matching filter, one of these metrics is selected based on a characteristic of the channel or these metrics are combined, when a transmitted signal sequence transmitted from a transmission side is estimated based on a characteristic of a received signal and a channel using a list output Viterbi algorithm for deciding one or a plurality of survivors for each state of the Viterbi algorithm including one or more states. The operation speed and the characteristic of a channel can be improved using the smallest circuit scale even if the characteristic of a channel has a long delay time, in a sequence estimation method and a sequence estimator.

Sequence estimation method and sequence estimator

A frequency error estimating apparatus for estimating a frequency error between a local oscillation frequency and a carrier frequency of a received signal in a receiver includes a frequency error estimating unit ( ) that suppresses a noise component included in the received signal according to a filter coefficient input to an averaging filter ( ), and estimates a frequency error based on an output of the filter; and a filter coefficient determining unit ( ) that calculates a filter coefficient based on a differential of estimate values of the frequency error from a first symbol, and changes the characteristics of the filter. In the receiver, the frequency error estimating apparatus can secure high precision in estimating a frequency error without losing the level of following the time variation in the Doppler frequency.

Frequency error estimating apparatus and a frequency error estimating method

A digital data demodulating device that estimates the channel impulse response (CIR) based on a received signal, and performs a viterbi algorithm using the replica generated according to the estimated CIR, and the received signal. The digital data demodulating device of the present invention follows the time variation of the channel by sequentially estimating the CIR in the CIR estimating circuit. The replica generating circuit of the digital data demodulating device includes a device for storing the estimated CIR and replica for each block therein, for reading the estimated CIR at a specific timing and updating the replica. A digital data demodulating device which reduce circuit scale, operates in a high speed, and appropriately follows the time variation of the channel, even in a high bit transmission rate and in a high delay dispersion of the multipass wave contained in the received signal.

Growing community of inventors

Tokyo, Japan

Kazuo Tanada