426 results about "Frequency axis" patented technology

All data symbols used in data transmission of a modulated signal are precoded by switching between precoding matrices so that the precoding matrix used to precode each data symbol and the precoding matrices used to precode data symbols that are adjacent to the data symbol along the frequency axis and the time axis all differ. A modulated signal with such data symbols arranged therein is transmitted.

In an OFDMA-based cellular system, a frame of a downlink signal includes a common slot and traffic slots. The common slot includes a synchronization preamble and a cell search preamble. The synchronization preamble has a structure for synchronizing time and frequency, and the cell search preamble has a cell search structure. The traffic slot includes pilot symbols provided on the time and frequency axes. A cyclic prefix is used to estimate initial symbol synchronization, and the initial symbol synchronization and the synchronization preamble are used to synchronize the frame. The synchronization frame and the cell search preamble are used to estimate time and frequency synchronization. The cell search preamble is used to search cells. When the initial synchronization is performed, the cyclic prefix is used to track the frequency, the synchronization preamble is used to track symbol synchronization, and the cell search preamble is used to track fine frequency synchronization.

A method for transmitting burst allocation information by a base station in a broadband wireless communication system in which a transmitted frame includes symbols, and orthogonal subcarriers in a frequency axis constitute each of the symbols based on a predetermined time unit. The method includes the steps of generating a reduced connection identifier (CID) by reducing a basic CID of a mobile terminal connected to the base station when the basic CID exists within a preset range, and inserting an MAP, which includes an enabled field representing the reduced CID and one of use and non-use of the reduced CID, into the frame, and transmitting the frame to the mobile terminal.

Only the light at an overlapping wavelength of the transmission characteristics of at least two wavelength selecting filters is looped, and at least one of the wavelength selecting filters varies a selected wavelength. Since a loss due to the optical filters is small and there is not a loss caused by a highly reflecting film, the output of an external-resonator variable-wavelength laser can be increased. Optical circuit component (8) divides light input from external device (1) into at least two ports. Loop waveguide (11) interconnects at least ports (9, 10) divided by optical circuit component (8) in the form of a loop. At least two first wavelength selecting filters (12, 13) are inserted in series in a path of loop waveguide (11), and have periodic transmission characteristics on a frequency axis which are different from each other. At least one of first wavelength selecting filters (12, 13) varies the selected wavelength.

A computer implemented physical signal analysis method includes four basic steps and the associated presentation techniques of the results. The first step is a computer implemented Empirical Mode Decomposition that extracts a collection of Intrinsic Mode Functions (IMF) from nonlinear, nonstationary physical signals. The decomposition is based on the direct extraction of the energy associated with various intrinsic time scales in the physical signal. Expressed in the IMF's, they have well-behaved Hilbert Transforms from which instantaneous frequencies can be calculated. The second step is the Hilbert Transform which produces a Hilbert Spectrum. Thus, the invention can localize any event on the time as well as the frequency axis. The decomposition can also be viewed as an expansion of the data in terms of the IMF's. Then, these IMF's, based on and derived from the data, can serve as the basis of that expansion. The local energy and the instantaneous frequency derived from the IMF's through the Hilbert transform give a full energy-frequency-time distribution of the data which is designated as the Hilbert Spectrum. The third step filters the physical signal by combining a subset of the IMFs. In the fourth step, a curve may be fitted to the filtered signal which may not have been possible with the original, unfiltered signal.

An embodiment of a device for generating a note signal upon a manual input includes an operator to enable a user of the same as an input to define one or several points as an input signal, and a controller which is implemented to receive the input signal and to generate a note signal based on the input signal and an allocation function. The allocation function allocates one single or no tone to each point of a two-dimensional definition amount with a tone quality axis and a frequency axis. The definition amount has a plurality of base points. Here, exactly one tone is allocated to each of the base points.

An apparatus and method for transmitting and receiving a demodulation reference signal (DM RS) are disclosed. A method for controlling a base station (BS) to transmit a demodulation reference signal (Demodulation RS or DM RS) in a wireless communication system includes transmitting, by the base station (BS), a DM RS for a relay node (RN) to the relay node (RN) through a specific backhaul subframe to which an extended cyclic prefix (CP) is applied. The DM RS is transmitted over two resource elements (REs) of individual subcarriers having subcarrier frequency indexes 2, 5, 8 and 11 in a frequency axis within a second slot of the specific backhaul subframe.

Methods, apparatuses, and systems described herein generally relate to a reference signal generation and mapping. For example, a method comprises determining a first set of antenna ports for a demodulation reference signal (DM-RS) transmission; determining, based on the first set, a frequency index associated with four adjacent resource elements, wherein the four adjacent resource elements correspond to two adjacent symbols in a time axis and to two adjacent subcarriers in a frequency axis; generating, based on a first orthogonal cover code and a second orthogonal cover code, a DM-RS associated with the first set of antenna ports; and transmitting, via a mapping to the four adjacent resource elements, the DM-RS associated with the first set of antenna ports.

A communication method, and a processing in accordance with the priority can be performed with a simple configuration even in the case of the communication of the multi-carrier method.The sub-carriers on which high priority data is superimposed and the sub-carriers on which low priority data is superimposed are positioned alternately to be transmitted. At the receiving side, the reception symbol stream in which symbols are lined on the frequency axis is obtained by performing a predetermined reception processing. The delayed symbol stream in which the reception symbol stream is delayed for a predetermined time is added to the reception symbol stream to extract the signal components relating to the high priority data, so that the high priority data is decoded. Thus, the high priority data can be decoded promptly with a simple configuration, and a processing in accordance with the priority can be performed with a simple configuration even if the high priority data and the low priority data are transmitted at the same time by the multi-carrier method.

A communication semiconductor integrated circuit has a demodulator circuit built in a single semiconductor chip. The demodulator circuit is constructed to demodulate a received OFDM-modulated packet signal including a preamble that has two or more fixed-signal sequences, and to have a frequency-error estimating/correcting function that estimates the frequency error of the received signal by using the received preamble and corrects the received signal for the frequency error, a fast Fourier transform function (FFT portion 210) that converts the time-axis information of the corrected received signal to frequency-axis information, a transmission path response estimating/correcting function that estimates the status of the transmission path from the converted signal and corrects the received signal for the transmission path response, and an averaging function that averages the received signal after being corrected for the frequency error so that the averaging can be performed before the fast Fourier transform process.

An orthogonal variable spreading factor (OVSF) of one dimension represented by coding tree is extended into two dimensions and applied simultaneously in both directions, frequency axis direction and time axis direction when carrying out spreading of two dimensions of frequency axis direction and time axis direction. For example, the transmission data is first spread by OVSF code of one dimension in the frequency axis direction (obtained from frequency axis direction OVSF code assignment section 11), and the result is spread by OVSF code of one dimension in time axis direction (obtained from time axis direction OVSF code assignment section 13, which is selected independent of frequency axis direction) in each of two-dimensional spreading sections 1-1 to 1-8.

The present invention relates to a demodulation device and a demodulation method, and its object is to demodulate subcarrier components utilizing estimated delay profiles to control the timing for performing a Fourier transform and the pass band of an interpolation filter used in interpolating transmission channel characteristics along a frequency axis so as to suppress unnecessary noise components, whereby an error rate after the demodulation is reduced. To achieve the object, in a demodulation device according to the present invention, a Fourier transform unit 1 performs a Fourier transform according to a timing signal and an interpolation filter unit 18 sets a pass band of a frequency interpolation filter used for interpolation along the frequency axis based on a signal corresponding to a maximum delay time, whereby the frequency band of a transmission channel characteristic corresponding to a subcarrier component is restricted when it is output.

An information extraction unit extracts spectral envelope information of L-dimension from each frame of speech data. The spectral envelope information does not have a spectral fine structure. A basis storage unit stores N bases (L>N>1). Each basis is differently a frequency band having a maximum as a peak frequency in a spectral domain having L-dimension. A value corresponding to a frequency outside the frequency band along a frequency axis of the spectral domain is zero. Two frequency bands of which two peak frequencies are adjacent along the frequency axis partially overlap. A parameter calculation unit minimizes a distortion between the spectral envelope information and a linear combination of each basis with a coefficient by changing the coefficient, and sets the coefficient of each basis from which the distortion is minimized to a spectral envelope parameter of the spectral envelope information.

A channel estimation apparatus of the present invention includes a preamble channel operation unit for carrying out an operation on pilot channel estimation values of pilots, which are transmitted from a transmitting antenna that transmits a preamble, as an improved pilot channel estimation value by employing a preamble channel estimation value based on a preamble included in received signals respectively received by a plurality of receiving antennas, a first channel estimation unit for estimating a channel for each of the receiving antennas through interpolation of a symbol axis and a frequency axis employing the improved pilot channel estimation value, and a second channel estimation unit for estimating a channel for each of the receiving antennas through interpolation of a symbol axis and a frequency axis employing pilot channel estimation values of pilots transmitted from the same transmitting antenna, of pilots transmitted from a transmitting antenna that does not transmit the preamble, of a plurality of transmitting antennas.

A frequency spectrum is detected by analyzing a frequency of a voice waveform corresponding to a voice synthesis unit formed of a phoneme or a phonemic chain. Local peaks are detected on the frequency spectrum, and spectrum distribution regions including the local peaks are designated. For each spectrum distribution region, amplitude spectrum data representing an amplitude spectrum distribution depending on a frequency axis and phase spectrum data representing a phase spectrum distribution depending on the frequency axis are generated. The amplitude spectrum data is adjusted to move the amplitude spectrum distribution represented by the amplitude spectrum data along the frequency axis based on an input note pitch, and the phase spectrum data is adjusted corresponding to the adjustment. Spectrum intensities are adjusted to be along with a spectrum envelope corresponding to a desired tone color. The adjusted amplitude and phase spectrum data are converted into a synthesized voice signal.

A millimeter wave band communication apparatus includes a millimeter wave band transmitter receiving a plurality of input modulation signal waves to transmit a millimeter wave band multiplex signal wave, and a millimeter wave band receiver receiving the transmitted millimeter wave band multiplex signal wave to restore the plurality of input modulation signal waves. The millimeter wave band transmitter includes a frequency arranging circuit generating a multiplex signal wave having respective frequency bands of the plurality of input modulation signal waves arranged on the frequency axis independent of each other, a frequency up-converter up-converting the generated multiplex signal wave to the millimeter wave band, and a transmission circuit transmitting the millimeter wave band multiplex signal wave. The millimeter wave band receiver includes a reception circuit receiving the millimeter wave band multiplex signal wave, a frequency down-converter down-converting the millimeter wave band multiplex signal wave from the millimeter wave band, and a frequency rearranging circuit restoring the down-converted multiplex signal wave into the plurality of input modulation signal waves respectively having the former frequency bands.

An apparatus and method reduce power consumption in a broadband wireless communication system. A transmitting end apparatus that includes a plurality of transmit (Tx) antennas includes a control block, a Processor (DSP) block, a modem block, and at least one power controller. The control block determines a traffic amount based on an amount of used resources. The Digital Signal Processor (DSP) block performs scheduling by using a subset of Tx antennas and a subset of resources on a frequency axis if the traffic amount is less than a threshold. The modem block applies boosting to a signal transmitted using the subset of resources. And at least one controller turns off an operation of at least one power amplifier that corresponds to at least one Tx antenna that is not included in the subset of Tx antennas.

An apparatus and method for allocating resources in an Single Carrier-Frequency Division Multiple Access (SC-FDMA) communication system are provided, in which a Node B determines on a cell basis whether to turn or off inter-subband hopping and whether to turn on or off mirroring for a resource unit for the UE on a frequency axis along which at least two subbands are defined, at set hopping times, selects a resource unit by selectively performing inter-subband hopping and mirroring on the resource unit for the UE according to the determination, and allocates the selected resource unit to the UE.