60results about How to "Reduce cross-correlation" patented technology

A system comprises a plurality of acoustic transmitters, mounted inside the streamers, adapted to transmit broadband signals having low cross-correlation between the signals of different transmitters; a plurality of acoustic receivers, mounted inside the streamers, adapted to receive the signals from the transmitters; at least one processor adapted to cross-correlate the signals received at the receivers with copies of transmitter signals to determine identities of the transmitters of the received signals and to determine travel times of the received signals; and a main processor adapted to convert the travel times to distances between the identified transmitters and the receivers and to determine relative positions of the streamers from the distances.

A method, device and system for determining a receiver location using weak signal satellite transmissions. The invention involves a sequence of exchanges between an aiding source and a receiver that serve to provide aiding information to the receiver so that the receiver's location may be determined in the presence of weak satellite transmissions. With the aiding information, the novel receiver detects, acquires and tracks weak satellite signals and computes position solutions from calculated pseudo ranges despite the inability to extract time synchronization date f, 'n the weak satellite signals. The invention includes as features, methods and apparatus for the calibration of a local oscillator, the cancellation of cross correlations, a Doppler location scheme, an ensemble averaging scheme, the calculation of almanac aiding from a table of orbit coefficients, absolute time determination, and a modified search engine.

Different carrier frequencies are chosen for plural transmitters of a transmitting device and signals are transmitted at frequency bands overlapping each other. In the receiving device weighting coefficients are provided in input-to-output paths of an interchannel interference canceller 21 so that the cross correlation between output signals from the interchannel interference canceller is minimized.

It is an object to provide a sequence allocating method that, while maintaining the number of Zadoff-Chu sequences to compose a sequence group, is configured to make it possible to reduce correlations between different sequential groups and between same sequential groups. This method comprises the steps of setting a standard sequence with a standard sequence length (Nb) and a standard sequence number (rb) in a step (ST101), setting a threshold values (Xth1(m)) and (Xth2(m)) in accordance with an RB number (m) in a step (ST103), setting a sequence length (N) corresponding to RB number (m) in a step (ST104), judging whether ¦r/N−rb/Nb¦=Xth1(m) is satisfied in a step (ST106), judging whether ¦r/N−rb/Nb¦=Xth2(m) is satisfied in a step (ST107), including Zadoff-Chu sequences with a sequence number (r) and a sequence length (N) in a sequence group (rb) in a step (ST108); if both judgments are positive, and allocating the sequence group (rb) to the same cell in a step (ST113).

The method is applicable to long-term evolution system. The idea of the invention is that combination of time division multiplex (TDM) and frequency division multiplex (FDM) is adopted in RACH design, and combinations of multiple code words are adopted for RACH precursor. Relative to individual FDM, TDM, and CDM (code division multiplexing), technical scheme of the invention can obtain larger number of access users, and reduce interference between multiple users, and multiple sectors, use less number of correlator, and lowers complexity of sequence design.

The present application provides a sequence-based signal processing method, communication device and communication system. The sequence used to transmit the signal satisfying the PUCCH is determined,the sequence is a sequence {fn}comprising 12 elements, fn refers to the elements in the sequence {fn}, and the determined sequence is a sequence satisfying a preset condition. Then, the 12 elements inthe sequence are respectively mapped to 12 sub-carriers to generate a first signal and transmit the first signal. With the sequence determined above, it is possible to maintain low cross-correlationbetween sequences while maintaining low PAPR and CM values when signals are transmitted using the PUCCH, thereby satisfying a communication application environment in which signals are transmitted using the PUCCH.

A method that is sub-optimal, but easily implemented, for cross correlation mitigation of GPS signals. It involves adaptive modification of the locally generated code used to detect a weak signal so that the new code is orthogonal to the jamming signals currently being tracked. The method employs simple constraints to achieve the orthogonalisation rather than a direct orthogonalisation performed using matrix inversions.

It is an object to provide a sequence allocating method that, while maintaining the number of Zadoff-Chu sequences to compose a sequence group, is configured to make it possible to reduce correlations between different sequential groups. This method comprises the steps of setting a standard sequence with a standard sequence length (Nb) and a standard sequence number (rb) in a step (ST101), setting a threshold value (Xth(m)) in accordance with an RB number (m) in a step (ST103), setting a sequence length (N) corresponding to RB number (m) in a step (ST104), judging whether ]r/N-rb/Nb]<=Xth(m) is satisfied in a step (ST106), including a plurality of Zadoff-Chu sequences with a sequence number (r) and a sequence length (N) in a sequence group (rb) in a step (ST107) if the judgment is positive, and allocating the sequence group (rb) to the same cell in a step (ST112).

The present application provides a sequence-based signal processing method, communication device and communication system. The sequence used to transmit the signal satisfying the PUCCH is determined,The sequence is a sequence {fn}comprising 12 elements, fn refers to the elements in the sequence, and the determined sequence {fn} is a sequence satisfying a preset condition. Then, the 12 elements inthe sequence are respectively mapped to 12 sub-carriers to generate a first signal and transmit the first signal. With the sequence determined above, it is possible to maintain low cross-correlationbetween sequences while maintaining low PAPR and CM values when signals are transmitted using the PUCCH, thereby satisfying a communication application environment in which signals are transmitted using the PUCCH.

The invention discloses a wavelet constant modulus blind equalization method in a MIMO (Multiple Input Multiple Output) system from the aspect of reducing?inter channel?and inter signal?correlation, so as to overcome defects that the traditional constant modulus blind equalization method in the MIMO system is weak in inter channel interference inhibition ability, slow in the convergence rate and large in steady-state errors. According to the method, singular value decomposition is used for reducing the correlation of channel output signals; an orthogonal wavelet base function is used for carrying out orthogonal wavelet transformation on MIMO channel output signals and autocorrelation of input signals of a blind equalizer is reduced; on the basis of fully considering the inter channel correlation, a cost function of MIMO system constant modulus blind equalization algorithm is redefined, and cross-correlation of output signals of the blind equalizer is reduced; and a variable step size function is used for controlling a blind equalization?weight vector?updating process, the convergence rate quickened, and the steady-state errors are reduced.

The present invention provides a signal processing method and device based on a sequence. A sequence used for meeting PUCCH (Physical uplink control channel) sending signals is determined, the sequence is a sequence {fn} comprising N elements, the fn shows the elements in the sequence {fn}, the determined sequence {fn} is a sequence meeting a preset condition, the N elements in the sequence {fn} are respectively mapped on N carriers to generate first signals for transmission. The determined sequence is determined to maintain the low cross correlation between the sequences when the PUCCH sending signals are used and maintain a low PAPR (Peak to Average Power Ratio) value and a CM (Cubic Metric) value so as to meet the communication application environment of employing the PUCCH sending signals.

The invention provides a sequence-based signal processing method, signal processing device and computer readable storage medium. The method comprises the following steps: determining a sequence used for meeting a reference signal or a control channel sending signal; wherein the sequence is a sequence [fn] comprising N elements, the fn refers to elements in the sequence [fn], the determined sequence [fn] is a sequence meeting a preset condition, and then the N elements in the sequence[fn] are respectively mapped to N subcarriers to generate a first signal and send the first signal. By utilizing the determined sequence, low cross-correlation between the sequences can be kept, and a reference signal or a control channel can keep a lower PAPR value and a lower CM value, so that a communication application environment for transmitting a signal by utilizing the reference signal or the control channel is met, especially when/2 <-> is transmitted; And when the BPSK modulates the data signal or carries out frequency shaping filtering on the reference signal or the control channel.

The invention discloses an LFM pulse train signal waveform design method based on pulse width agility. The method comprises the steps: setting different pulse widths for different pulses in an LFM pulse train with the same bandwidth, so that each pulse signal has different modulation rates, and the cross correlation between the pulses is reduced so as to effectively improve the range gating characteristic and the folding clutter resistance of the generated LFM pulse train signal and achieve the purpose of suppressing range ambiguity and resisting folding clutter.

The invention provides a signal processing method and device. The method comprises the step that in frequency domain resources of a comb tooth structure, reference signals mapped on the frequency domain resources of different comb teeth can be generated by different sequences. That is to say, the reference signals on different frequency domain resources can be generated by adopting different sequences, so that the performance of the reference signals transmitted on the frequency domain resources of the whole comb tooth structure is improved.

The invention discloses an airborne equipment electromagnetic compatibility grading method based on an unascertained measurement theory. The method comprises the following steps of S1, measuring the grading evaluation indexes of the electromagnetic compatibility of airborne equipment, and building a grading evaluation index set; S2, establishing a measurement function of grading evaluation indexes by applying an uncertain measurement theory; S3, solving a single index evaluation matrix of the electromagnetic compatibility of the airborne equipment; S4, solving a grading evaluation index weight of each electromagnetic compatibility by using an information entropy method; S5, solving the comprehensive attribute measure of each airborne device; S6, solving quantitative grading or classification of the electromagnetic compatibility of the airborne equipment on the airplane; and S7, obtaining the electromagnetic compatibility design priority and design weight of the airborne equipment. According to the method, the cross correlation of evaluation indexes is low, the evaluation indexes can be measured and examined, the evaluation indexes can serve as a priority strategy for system-level electromagnetic compatibility index distribution, and a theoretical basis is provided for quantitative design of electromagnetic compatibility of the whole aircraft system.