摘要:
A method is provided for correlating a received satellite radio-navigation signal made up of a first pilot signal modulated with a first spreading code and a second data signal modulated with a second primary spreading code of a length equal to that of the first spreading code, the second data signal being further modulated with a secondary sequence comprising a plurality of chips, the duration of a chip being equal to a multiple of the length of the second primary spreading code, the first pilot signal and the second data signal being synchronous. The correlation method comprises the following steps: first correlations, over a plurality N of periods of the first spreading code, of the radio-navigation signal with the first spreading code; the selection, out of the N first correlations, of a subset containing a number M of correlations; and the coherent integration of the M correlations of the subset.
摘要:
Embodiments of a master station and method for high-efficiency Wi-Fi (HEW) communication using traveling pilots are generally described herein. In some embodiments, the master station is arranged for communicating with a plurality of HEW and may be configured to transmit, during an initial portion of an HEW control period, a master-sync transmission that includes a multi-device HEW preamble arranged to signal and identify data fields for a plurality of scheduled HEW stations. The master station may transmit during the HEW control period the data fields with traveling pilots to the scheduled HEW stations. The master station may also receive data fields with traveling pilots transmitted by the scheduled HEW stations during the HEW control period. The traveling pilots may comprise pilot signals that are shifted among orthogonal-frequency multiplexed (OFDM) subcarriers during transmission of one or more of the data fields.
摘要:
A parametric form of G-Rake and chip equalization for closed-loop transmit diversity is provided, that accounts for impairment correlation between transmit antennas. In a closed-loop transmit diversity system, the base station transmits a signal from two or more antennas, using one of a predetermined set of relative phase offsets at one of the antennas. The parametric estimation of the impairment or data covariance is performed by summing terms, including a term for each possible phase offset. The terms are weighted by fitting parameters. The fitting parameters are jointly solved by fitting the impairment or data covariance estimate to a measured impairment or data covariance. In another aspect, a measured impairment covariance is formed by exploiting a special relationship between the pilot channels of the different transmit antennas.
摘要:
A method and apparatus are provided that optimizes a transmitted user-specific signal. In one embodiment, the invention includes receiving signals from a remote radio, deriving estimates of receive channels corresponding to the received signals using the received signals, deriving a model of an expected transmit channel to the remote radio based on the receive channel estimates, deriving a set of transmit parameters to be applied to an array of transmit antennas to transmit a signal to the remote radio by optimizing a transmit power criteria using the model of the expected transmit channel and constraints on the estimated quality of a signal transmitted over the expected transmit channel, and transmitting to the remote radio by applying the derived set of transmit parameters to the transmit antenna array.
摘要:
A method of initializing en equalizer of VSB DTV receiver and an equalizer using the same are provided. The method includes the steps of: obtaining a channel estimation value by estimating an impulse response of a channel from a received signal, initializing the backward filter by using the channel estimation value; generating an imaginary training signal by an arithmetical operation for the channel estimation value and an generated known training sequence; and initializing the forward filter by using the imaginary training signal.
摘要:
A digital transmission system comprising a receiver, the receiver including a receiver input stage and a digital memory for storing a sequence of binary symbols of sample values, formed in the receiver input stage, of a signal distorted by a transmission channel, and an equalizer for forming a sequence of binary estimates from the sample values by an impulse response of a substitute system describing the transmission channel, the impulse response being determined by first correlations of coefficients of a known training sequence with the sample values of a part of the known training sequence extended by at least one binary symbol. To make a channel estimation possible for a higher degree of the impulse response of the transmission channel, and also to carry out the channel estimation always with a maximum quality, a variable first correlation window size and a variable number of first correlations are used for adapting the impulse response of the substitute system to the impulse response of the transmission channel. A reduction of the correlation window size enables more cross-correlation values to be formed with one sequence of sample values, so that an increase of the degree of the impulse response of the estimated transmission channel becomes possible. With a more favorable transmission behavior, the correlation window size can be extended by one or more known binary symbols, so that the quality of the estimate of the impulse response is enhanced.
摘要:
Radiotelephone communications, such as voice or data, are processed to produce a pilot symbol assisted modulation (PSAM) communications symbol sequence, the PSAM communications symbol sequence including a plurality of predetermined pilot symbols interleaved with a plurality of information symbols representing the radiotelephone communications. The PSAM communications symbol sequence is communicated over a radiotelephone communications channel having a transfer characteristic, producing a sequence of communications symbol data representing the communicated sequence of communication symbols. Pilot symbol data, corresponding to pilot symbols, and information symbol data, corresponding to information symbols, are identified in the sequence of communications symbol data. A data-augmented estimate of the transfer characteristic of the radiotelephone communications channel is generated from the pilot symbol data and the information symbol data. Estimates of information symbols are generated from the corresponding information symbol data and the generated estimate of the transfer characteristic. Radiotelephone communications are decoded from the generated estimates of the information symbols. Preferably, estimates of the transfer characteristic are iteratively generated by identifying a group of information symbol data corresponding to a group of information symbols, generating estimates of the group of identified information symbols from the group of information symbol data and a previously generated estimate of the radiotelephone communications channel transfer characteristic, and generating a new estimate of the transfer characteristic from the pilot symbol data, the information symbol data, and previously generated estimates of information symbols.
摘要:
A two-way transmitting apparatus which transmits display data and audio signal from an audio reproducing device to a remote controller and headphones with display by wireless transmitting, and transmits control signals to the audio reproducing apparatus according to one of the operation of a plurality of operation unit established on the remote controller and the headphones. The control data is divided into a predetermined number of blocks, the discrimination code "d" is inserted between respective blocks to generate the data sequence, and the data length per unit block is set to most approximate to the value of square root of the control data length.
摘要:
An apparatus for adaptive-power control of a spread-spectrum transmitter of a mobile station operating in a cellular-communications network using spread-spectrum modulation. A base station transmits a first spread-spectrum signal. A mobile station has an automatic-gain-control circuit for generating an AGC-output signal, from a received signal. The received signal includes the first spread-spectrum signal and an interfering signal. The mobile station also has a correlator for despreading the AGC-output signal, a power-measurement circuit responsive to processing the received signal with the despread AGC-output signal for generating a received-power level, a comparator coupled to the power-measurement circuit for generating a comparison signal by comparing the received-power level to a threshold level, a transmitter for transmitting a second spread-spectrum signal, an antenna, and a variable-gain device responsive to the comparison signal for adjusting a transmitter-power level of the second spread-spectrum signal.