摘要:
Embodiments of the present invention provide a method, an apparatus, and a system for frequency offset estimation and channel estimation, relate to the field of wireless communication technologies, and can increase the accuracy of frequency offset estimation and channel estimation in a distributed microwave MIMO system. The method for frequency offset estimation and channel estimation includes: when interference signals in received data are not obtained, performing frequency offset estimation on the received data, and obtaining a frequency offset estimation result; after the interference signals in the received data are obtained, performing frequency offset estimation on the received data according to the interference signals, and obtaining a frequency offset estimation result; performing channel estimation on the received data according to the frequency offset estimation result, and obtaining a channel estimation result; obtaining the interference signals according to the frequency offset estimation result and the channel estimation result, where the interference signals are used as parameters of the frequency offset estimation.
摘要:
The present invention provides a carrier wave reproduction device in which bit-error characteristics are improved without decreasing transmission capacity. The carrier wave reproduction device is equipped with an interpolation filter that estimates a phase error for a received symbol on the basis of a pilot symbol included in the received symbol, a first phase rotation machine that rotates a phase of the received symbol in response to the phase error estimated by the interpolation filter and then outputs the rotated symbol as a first output symbol, a phase error compensating unit that compensates for the phase error remaining in the first output symbol and then outputs the result of the compensation as a second output symbol, a QAM symbol demapping unit that calculates both a first bit string corresponding to the first output symbol and a second bit string corresponding to the second output signal, and an error correction decoder which performs error correction on the bit error in the first bit string and outputs the result. The phase error compensating unit refers to the first bit string after error correction has been performed thereon and then compensates for the phase error remaining in the first output symbol.
摘要:
A digital radio receiver is adapted to receive radio signals modulated using continuous phase modulation. The receiver includes components for receiving analogue radio signals having various carrier frequencies and a plurality of correlators corresponding to different bit sequences. Each of the plurality of correlators share a common estimator for estimating a frequency offset between the radio signals carrier frequencies and nominal carrier frequencies. The receiver further includes components allowing the estimator to determine which of the correlators produce the most optimal output signal.
摘要:
The present invention provides a cycle-slip detection method and apparatus, and a receiver. If an absolute value of a first difference obtained by subtracting a phase of the first symbol in the k th training sequence cycle from a phase of the last symbol in the (k-1) th training sequence cycle in a received signal is greater than a cycle-slip determining threshold, it is determined that a cycle-slip occurs in the k th or (k-1) th training sequence cycle. Further, if a second difference obtained by subtracting a phase of the first symbol in the (k+1) th training sequence cycle from a phase of the last symbol in the k th training sequence cycle is greater than the cycle-slip determining threshold, and signs of the first difference and the second difference are opposite, it is determined that a cycle-slip occurs in all symbols in the k th training cycle; or if no, it is determined that a cycle-slip occurs in a data symbol in the (k-1) th training sequence cycle, and a position of the cycle-slip is located. In the present invention, a position at which a cycle-slip occurs can be accurately determined, to avoid a problem of burst continuous bit errors in a received signal caused by the cycle-slip.
摘要:
A system, method and device for frequency acquisition. In particular, the embodiments allow for a mobile telephone to simultaneously receive data and/or voice signals while acquiring a GPS signal for its navigation feature. The system, method and device of the present embodiments employ a digital rotator and a local oscillator in concert to acquire the respective signals, correct any frequency errors associated with those signals, and maintain a local timing reference suitable for receiving and transmitting data through a mobile network while simultaneously providing an accurate location through a GPS system.
摘要:
A receiver comprises a carrier tracking loop (CTL), a filter, a look-up table and a rotator. The CTL provides a baseband signal having in-phase and quadrature signal components. The filter provides a DC-offset level associated with each component to the look-up table, which, in response thereto, provides a phase adjustment signal to the rotator. The latter then rotates the baseband signal as a function of the phase adjustment signal for correcting for carrier phase ambiguity.
摘要:
An apparatus of compensating for a frequency offset using a guard interval and a pilot symbol, which are inserted at a transmitter, in an OFDM (Orthogonal Frequency Division Multiplexing) system. The OFDM system receives an OFDM signal in which a pilot symbol is inserted in data of a frame unit at regular intervals and a guard interval is inserted in a data symbol. In the system, a first carrier synchronizer receives a data symbol stream obtained by converting the OFDM signal to digital data, and detects a guard interval of each data symbol, to compensate for a coarse frequency offset. A fast Fourier transform part OFDM-demodulates a signal output from the first carrier synchronizer. A second carrier synchronizer detects the pilot symbol from the demodulated data symbol stream to compensate for a fine frequency error.
摘要:
Die Erfindung bezieht sich auf ein Verfahren zur Trägerrückgewinnung für einen Synchron-Demodulator (SD), bei dem ein Eingangssignal (in) bereitgestellt wird, ein Träger (tr) für das bereitgestellte Eingangssignal (in) rekonstruiert wird und das Eingangssignal (in) und der Träger (tr) gemischt werden, um ein auszugebendes Mischsignal (i, q) zu erzeugen, wobei zum Bereitstellen eines Ausgangssignals (io, qo) ein restlicher Phasenfehler des mischsignals (i, q) mittels einer Phasenverschiebung korrigiert wird. Außerdem wird eine entsprechende Schaltung zum Durchführen eines solchen Verfahrens vorgeschlagen.