1600 results about "Iterative method" patented technology

A computationally efficient pulse shaping method for OFDM that produces mutually orthogonal transmission pulses having fast spectral decay is provided. The pulse shaping method comprises an iterative method for designing OFDM transmission pulses that satisfy prescribed time-frequency localization conditions. The iterative method may be implemented in a computationally efficient way and can be used to adapt the transmission pulses to time-varying channel conditions in real-time, thereby maximizing the bit-error performance of an OFDM system while maintaining high data rates in wireless transmission.

The present invention relates to improved multiple access communications. In one form, the invention relates to an improved signal processing method and apparatus for an iterative method of determining the reception of a signal in a multi user packet based wireless OFDM (Orthogonal Frequency Division Multiplexing) communication system. In other forms the present invention provides recursive filtering for joint iterative decoding in a variety of systems and functions such as linear multiple access channel decoders, iterative equalisation, iterative joint channel estimation and detection/decoding, iterative space-time processing, iterative multi user interference cancellation and iterative demodulation. In one particular form the present invention provides an iterative decoding circuit for a wireless multiuser communications receiver comprising a first signal processing means for receiving at least one received signal, said first signal processing means comprising at least two linear iterative filters such that the first linear iterative filter provides an estimate of a selected received signal to an estimated signal output and a second linear iterative filter provides estimates of at least one other received signal, delayed by one iteration cycle, to an input of said first linear iterative filter, a second signal processing means for receiving the estimated signal output of the first linear iterative filter and providing a further received signal estimate to the input of the first signal processing means in a succeeding iteration cycle of the decoding circuit.

An iterative method (400) and apparatus (200) for a receiver for reducing interference in a desired signal in a GSM communication system uses a finite-impulse-response filter combined with alternate quadrature component output selection for alternate linear equalization are disclosed The method includes inputting a burst of data of a received waveform including interference, training an alternate linear output filter with a midamble of known quadrature phase, providing an estimate of the desired signal by operating on the received waveform with the finite-impulse-response filter, generating log likelihood ratio estimates for a plurality of bits in the burst of data, selecting bits from the burst of data base upon a predetermined condition, and re-training the alternate linear output filter to provide a second improved estimate of the desired signal.

An integrated FIB/PEM apparatus and method for performing failure analysis on integrated circuits. In-situ failure analysis is enabled by integrating Photon Emission Microscopy into a Focused Ion Beam system, thereby improving throughput and efficiency of Failure Analysis. An iterative method is described for identifying and localizing fault sites on the circuit.

We present an iterative method for reducing artifacts in computed tomography (CT) images. First, a filter is applied to the experimental projection data that adaptively expands the detector element size in regions with low photon counts, until the desired number of photons are detected. The initial image is then calculated using an existing reconstruction technique. In each iteration, artifacts and noise in the current image are reduced by using an edge-preserving blur filter. Metal pixels (determined from the initial image) are replaced with smaller values. The resulting image is forward projected. Rays that go through metal are replaced with the forward projected values. Rays that do not pass near metal are kept at the experimental values. Filtered backprojection is then performed on the new projection data to determine the updated image. Finally, after the last iteration, metal pixels are copied from the initial image.

A wireless communication receiver, such as the receiver included in a wireless communication transceiver implemented in a base station or in a mobile station of a wireless communication network, includes a parametric G-RAKE receiver circuit and a method that compute parametric scaling parameters on a per transmission interval basis. In one embodiment, measured impairment correlations are obtained for an individual transmission slot and used to estimate instantaneous values of the scaling parameters. One or both of those instantaneous values are then constrained according to one or more defined limits. In other embodiments, multiple transmission slots are used to increase the number of measurements available to estimate the scaling parameters, with parameter constraining optionally applied. Further embodiments use iterative methods and/or solve for one parameter, and use the results to obtain the other parameter(s). One or more of these embodiments can be improved through the use of error correction/detection information.

A method and system are disclosed for finding virtual tooth features on virtual three-dimensional models of the teeth of patients. The tooth features comprise marginal ridges, cusp tips, contact points, central groove and buccal groove. Tooth axes system plays a key role in identifying the tooth features. An iterative method is disclosed for improving the accuracy of the tooth axes system. A virtual three-dimension model preferably obtained by scanning the dentition of a patient forms the basis for determining the tooth features. Tooth features are derived for all categories of teeth including molars, premolars, canines and front teeth. Tooth features are very helpful and used in planning orthodontic treatment. The tooth features are determined automatically using the computerized techniques; and can be manually adjusted when necessary.

The invention belongs to the electrical power system domain, specially relates to the line single end fault distance measuring method of the anti- distributed capacity electric current and the transition resistance influence. Including: surveys the transformer substation protection installment place fault phase voltage, the phase current, the zero sequence voltage, the zero sequence electric current and the negative sequence electric current as the input value; using the fault voltage cross zero time to measure the resistance characteristic which is not influence by transition resistance, from the protected line begin end start, computing the measure voltage real part computed value of the fault point voltage cross zero point time, compared with the measured value of the measure voltage real part, computing the error; and taking the delta-S as the step size, in turn computing the setting range which is protected by the send tripping signal, if cannot obtain the protect tripping signal, searching the total track length which is protected, taking the minimum point as the fault point. The invention method is not influenced by the distributed capacity electric current and transition resistance, does not have the false root problem of solving equation method and non convergence question of the iterative method, and has the very high practical value.

When an array of proximity sensors is used as a keyboard, it can provide an ambiguous output if a user's finger overlaps several keys or if liquid is spilled on the keyboard. This ambiguity is reduced by an iterative method that repeatedly measures a detected signal strength associated with each key, compares all the measured signal strengths to find a maximum, determines that the key having the maximum signal strength is the unique user-selected key and then suppresses or ignores signals from all other keys as long as the signal from the selected key remains above some nominal threshold value.

The invention discloses a line single-phase earth fault single-terminal location method based on positioning function amplitude characteristics. The method comprises the following steps of: measuring fault phase voltage, fault phase current, fault phase negative-sequence current and zero-sequence current at a protection installation position of a transformer substation as input variables; with the origin of a protected line as a start point, calculating the positioning function amplitude of each point on a fault phase line one by one in a way that step length increases gradually till a trip signal setting range is reached; if protection trip signals cannot be obtained, searching all over the protected line, taking the point with the smallest positioning function amplitude as a fault pointand setting the distance between the point and the line protection installation position. The method is not influenced by distributed capacitance, or load current or transition resistance, does not have the problems of false root existing in the method of solving equation or non-convergence existing in the iteration method and achieves very high practical value.

A system and method for monitoring and managing electrical power transmission and distribution networks through use of a deterministic, non-iterative method using an holomorphic embedding and algebraic approximants for determining the real-time load flow in a power generating system having an electrical grid. Such method may be employed for real-time or off-line applications for electric power systems reliability assessment, and is capable of determining whether or not a physical solution to the load flow problem exists, or if the system is in a state of voltage collapse.

An accurate calibration method of micro inertia measuring unit by decoupling erection error angle (EEA)with scale factor includes setting up MIMU integral error model and separating couple between EEA of accelerometer and gyroscope and scale factor ,using position error canceling method to calculate out and to separate out scale factor and EEA of accelerometer as well as using least square method and iteration method to calculate out EEA of gyroscope and its relative error items in 10 position static calibration test and in 3 direction positive and negative rate test ,then using interpolation method to calculate out scale factor of gyroscope .

An iterative method enabling a request plan to be established for an observation satellite. A plan consists in a succession of requests which are associated with pluralities of opportunities for satisfying said requests. The plan must also comply with a plurality of constraints. Each iteration k of the iterative method is made up of the following steps:new opportunity is selected;a provisional plan is derived from the preceding plan k-1 as calculated in-the preceding iteration, and from the new opportunity;provisional plan is verified for compliance with said plurality of constraints;the quality of said provisional plan is evaluated; andit is determined whether the provisional plan should be confirmed as plan k as a function of the quality of said provisional plan and of the quality of said preceding plan k-1.In the method, it is decided whether or not to confirm the provisional plan by a probabilistic metaheuristic of the simulated annealing type, and by the rule for constructing the provisional plan as a function of the newly selected opportunity.

Stable adaptive filter and method are disclosed. The invention solves a problem of instability associated with Fast Affine Projection adaptive filters caused by error accumulation in an inversion process of an auto-correlation matrix. The Stable FAP uses a simplification of setting a normalized step size close to unity and reduces a problem of the matrix inversion to solving a system of linear equations whose solution coincides with a first column of the inverse auto-correlation matrix. The system of linear equations is then solved by one of descending iterative methods which provide inherent stability of operation due to intrinsic feedback adjustment. As a result, inevitable numerical errors are not accumulated, being corrected as the process goes on. In first and second embodiments of the invention the system of linear equation is solved by steepest descent and conjugate gradient methods respectively. Being immune to numerical errors, the invented method and filter are suitable for various DSP platforms, e.g., 16 and 24 bit fixed-point as well as floating point platform.