63 results about "Power delay profile" patented technology

Methods, apparatuses, and systems for improved channel estimation in an Orthogonal Frequency Division Multiplexing (OFDM) system are discussed. In one example discussed herein, joint two-dimensional Minimum Mean-Square Error (2D-MMSE) channel estimation is performed on any Resource Element (REs) containing a reference signal in a Resource Block (RB), one-dimensional Minimum Mean-Square Error (1D-MMSE) channel estimation is performed in the frequency domain on each OFDM symbol in the RB, and then channel estimation is performed in the time domain on each frequency sub-carrier in the RB. In another example discussed herein, Power Delay Profiles (PDPs) and/or frequency correlations are calculated using minimax optimization and then stored in a Look-Up Table (LUT) indexed by estimated Signal to Noise Ratio (SNR) and the estimated maximum delay spread. A portable device could use such an LUT in MMSE calculations.

A method of estimating a position of an object is disclosed. The method comprises receiving a plurality of signals transmitted between each of a respective plurality of reference stations of a known position and the object. The method further comprises, for each received signal: processing the signal using a matrix featuring a characteristic power delay profile and a characteristic signal waveform to provide a processed signal, and calculating a direct estimate of the position of the object based, at least in part, on the processed signals.

Exemplary systems and methods can be provided for measuring a parameter—e.g., channel impulse response and/or power delay profile—of a wideband, millimeter-wave (mmW) channel. The exemplary systems can include a receiver configured to receive a first signal from the channel, generate a second signal, and measure the parameter based on a comparison between the first and second signals; and a controller configured to determine first and second calibration of the system before and after measuring the parameter, and determine a correction for the parameter measurement based on the first and second calibrations. Exemplary methods can also be provided for calibrating a system for measuring the channel parameter. Such methods can be utilized for systems in which the TX and RX devices share a common frequency source and for systems in which the TX and RX devices have individual frequency sources that free-run during channel measurements.

There is provided a method of refining a timing estimate used to synchronize a femtocell base station to a macrocell base station. The method in the femtocell base station comprises estimating a multipath power delay profile from signals received from the macrocell base station, detecting the earliest path in the multipath power delay profile and determining a correction to the timing estimate from the earliest path detected in the multipath power delay profile.

The present invention relates to a method, apparatus, and computer program product, wherein frequency co-variances or correlations of a measured power delay profile or frequency correlation function are estimated at two different non-zero sub-carrier lags of an orthogonal frequency division multiplexing channel. A ratio of squared magnitudes of the two estimated frequency co-variances is calculated and a delay spread or coherence bandwidth of said channel is estimated based on the calculated ratio.

An adaptive transmission timing control system is provided in which a base station can correctly instruct a mobile station of a timing control signal indicating the amount of variation in transmission timing and a multipath situation can be estimated in the base station with accuracy. When control information for controlling transmission timing of an upstream signal of the mobile station is generated in the base station, the mobile station is notified of the control information in every frame of the upstream signal. Specifically, the control information is generated by determining the transmission timing using a power delay profile in which frames of the upstream signal are added and synthesized in every RTT (Round Trip Time) cycle of the upstream signal. This makes it possible to heighten resistance to an error in the timing control signal, and transmission timing control can be carried out correctly.

The present invention relates to a method and an apparatus for timing control of channel estimation. The method includes: sequentially shifting a channel estimation window in a power-delay profile in a specific time interval to obtain a plurality of candidate segments; sequentially calculating a metric corresponding to the candidate segments according to the delay paths and the channel power contained in the candidate segments; among the metrics, finding out an optimal segment with the maximum metric and deciding a timing of channel estimation based on the optimal segment.

The invention relates to a single-node indoor positioning method based on power delay profile and direction of arrival distance measurement. The invention aims to solve defects that an existing fingerprint map positioning system is low in positioning accuracy, the positioning accuracy depends on the performance of an approximation algorithm, fingerprint map positioning need to deploy a lot of positioning nodes in a positioning environment and acquire a fingerprint map in advance, a lot of material resources and financial resources are consumed, and that the single node is large in positioning implementation error. The process of the single-node indoor positioning method comprises the steps that firstly, an indoor positioning system receiver acquires a group A of channel state information; secondly, phase information and amplitude information in the channel state information are acquired; thirdly, error elimination is performed on the phase information in the acquired channel state information by adopting an interpolation method; fourthly , the amplitude information and the error eliminated phase information are processed so as to acquired a transmission distance; and fifthly, the customer location is solved based on trilateral positioning according to the the transmission distance acquired in the step four. The single-node indoor positioning method is applied to the field of indoor positioning.

A wireless transmit receive unit (WTRU) and methods are used in a wireless communication system to process sampled received signals to establish and/or maintain wireless communications. A selectively controllable coherent accumulation unit produces power delay profiles. A selectively controllable post processing unit passes threshold qualified magnitude approximation values and PDP positions to a device such as a rake receiver to determine receive signal paths.

Multipath components of transmitted data symbols are received with individual delays and processed by a RAKE unit having a number of fingers. A delay profile is calculated, and delay values for peaks detected therein are determined. A number of peak delay values (P<SUB>A1</SUB>, P<SUB>A3</SUB>, P<SUB>A4</SUB>, P<SUB>A5</SUB>) representing the largest peaks for the profile are pre-selected, and for each of them a signal-to-interference ratio for delay values in an interval around the pre-selected peak delay value is calculated. In each interval the delay value having the highest signal-to-interference ratio is selected and provided to the RAKE unit with each selected delay being assigned to a RAKE finger. Hereby the ability to select correct and accurate path delays can be improved also in time critical processes, where filtering of the delay profiles over several frames is not possible, because quite accurate delay values can be provided shortly after wake-up of the receiver.

The invention describes a method for adaptively scheduling activation of a path-searcher for a mobile terminal (1) operative in a telecommunication system. The mobile terminal (1) is capable of receiving multi-path signals (3, 4) originating from a scattered signal from a transmitter of at least one base station (2) in said system. The time lag between consecutive path-searcher activations is according to the method determined based on a value of the power delay profile discrepancy between two consecutive power delay profiles. The power delay profiles are derived from at least a subset of the powers of signals (3, 4) received at different delays during the path-searcher activation.

A path searching circuit is provided which is capable of searching a stable path. A power delay profile calculated by a powering section using an I component correlation value and a Q component correlation value is input to a power level change monitoring section, where a change in a power level is monitored at a sampling point for each of two or more delay profiles to be used for same power adding processing. With correct signal receiving path timing, stable high correlation values are observed, that is, it is observed that the received power level is small in change. On the other hand, with instantaneously high correlation values caused by noises, it is observed that the received power level is great in change. As a result, in the weighing coefficient controlling section, a weighing coefficient for correlation values providing a great change in a received power level is determined so that the received power level becomes low when power is added and so that weighing control is exercised.

Obtaining a timing reference in wireless communication is facilitated when desiring to communicate with a weak serving base station (such as an evolved Node B) in the presence of a stronger interfering base station. The user equipment (UE) may track a stronger interfering base station's timing, or the UE may track a timing that is derived by a composite power delay profile (PDP) from multiple base stations. The composite PDP may be constructed by adjusting individual base station PDPs according to a weighting scheme. The timing obtained in such a manner may be used for estimation of the channel of the interfering base station and cancelling interfering signals from the base station. It may also be used to estimate the channel of the serving base station after adding a backoff. The UE may track a stronger interfering base station's frequency, or the UE may track a composite frequency.