108 results about "Latency distribution" patented technology

An automated bandwidth monitoring and control method and system provides for real time, dynamic control of the allocation of bandwidth to selected applications in a communications network based on the selected operational context and the fixed bandwidth available at a network access point. A graphical user interface, using operational terms common to the overall enterprise in which and for which the network is implemented and understandable by an operator, displays the bandwidth allocation strategy, and in substantially real time displays statistics representative of actual bandwidth use at the access point, input functions for modifying the bandwidth allocation strategy in substantially real time and estimated message delay distributions for the applications of the strategy determined based on the actual bandwidth use statistics.

An orthogonal frequency division multiplexing (OFDM) demodulating apparatus includes a delay profile creating section, a Fourier converting section, a pilot signal extracting section, a transmission path characteristic estimating section, an inverse Fourier converting section, and a window control section. In this case, the window control section creates a delay profile for defining a calculation range by leaving a path which exists at a same position in both the delay profiles created by the delay profile creating section and the inverse Fourier converting section and the number of times of detection which is equal to or higher than a threshold value and defines a higher threshold value for the path at a predetermined position from the position of the main path within the delay profile created by the inverse Fourier converting section than for the paths at the other positions.

Search scheduling circuitry for use with a wireless communication device, such as a mobile telephone, includes a search time calculator, a search period calculator, a queue circuit, and a search time circuit. The search scheduler generates a prioritized list of cells to be adaptively searched in response to the network requirements and the capability of the search hardware. If there are very few “handoff” possibilities the search hardware may be turned off and then back on in time to meet the search rate requirements. However, if there is an excessive number of possibilities, the searcher list is prioritized and pared to assure the most likely candidates are searched. This search scheduling minimizes battery power consumption while meeting the search rate requirement and maximizes use of the search hardware for measuring signal quality from multiple neighboring cells and estimating the delay profile of active cells.

Correlations between the received signal to which pilot symbols have been applied at the transmitter end, and a correlation signal which contains the pilot symbols are carried out in the receiver in order to determine a path delay profile. Averaging processes are carried out over two or more delay profiles obtained in this way. Evaluations are carried out in one or more threshold value selection units (22.1, 22.2) on two or more averaged delay profiles with the aim of path selection. The parameters which govern the correlations and/or the averaging processes and/or the evaluations, and/or the repetition interval of these calculations are set as a function of the relative speed between the transmitter and the receiver, the frequency error between the carrier frequency of the received signal and the reference frequency that is set at the receiving end, and the noise level of the received signal. In the case of reception from two or more base stations, a final path selection is made in a finger allocation unit (40).

A path searching apparatus which is used in a base station apparatus according to the CDMA (Code Division Multiple Access) systems for increasing the accuracy for path detection depending on the number of communication channels to be processed. The path searching apparatus has a path searcher for generating a delay profile through to a path searching process composed of a plurality of processing units, an interpolation information storage for storing interpolation information indicative of whether an interpolation process for reducing a chip interval is to be performed or not before and after each of the processing units, an interpolation position processing control for enabling the path searcher to perform an interpolation process before and after each of the processing units based on the interpolation information stored in the interpolation information storage according to the number of the communication channels to be processed, and a path detector for detecting a reception path based on the delay profile generated by the path searcher.

A multi-path detection circuit can improve path detection accuracy in the environment where the path is located close in the extent of one chip in the multi-path detection circuit of CDMA type receiver unit. The multi-path detection circuit has generating means for generating a logic pattern of a correlated peak in the delay profile, and removing means for removing a power component of the detected correlated peak from the delay profile using the logical pattern of the correlated peak generated by the generating means.

A path search circuit according to the present invention has an orthogonal multi-beam forming section 4 for directional reception with a plurality of orthogonal multi-beams orthogonal one to another, correlation-operating sections 61–6M for correlation-operating outputs of the orthogonal multi-beam forming section 4 with a known signal, weight multiplying sections 81–8Nb for multiplying the output of the correlation-operating section 61–6M by a weight converted into a beam space, delay profile generating sections 91–9Nb for generating delay profiles from the output signals of the weight multiplying sections 81–8Nb, and a path detecting section 10 for detecting a reception timing and arrival direction of arrival path from the delay profile. This path search circuit can enhance the accuracy of path direction detection by the use of a directional reception signal, and further reduce the direction dependence of path timing detection accuracy.

An apparatus comprises a receiver receiving wireless transmission of a real radio system from at least one base station of a radio system as a function of reception direction. The transmission comprises predetermined data. The apparatus comprises also a processing unit that forms taps of a delay profile on the basis of comparison between the data that is received and corresponding predetermined data. The processing unit estimates direction for the taps of the delay profile on the basis of a reception direction of the transmission, and forms radio channel data by associating the taps of the delay profile with the estimated direction. The radio channel data is for a radio channel model of a MIMO emulation in an OTA chamber having a plurality of antennas around a test zone where a device-under-test may be placed.

A receiver of a mobile station or a base station in radio communications is formed by a correlation unit for generating a delay profile for specifying paths by taking correlations by using replica signals for a received pilot signal, and a path selection unit for comparing a power level of each path in the delay profile with a threshold determined according to an index value regarding a communication state, selecting paths for which a comparison result satisfies a prescribed condition as valid paths, and outputting a selected delay profile formed by the valid paths as a channel estimation value.

The present invention provides a search window delay tracking procedure for use in a multipath search processor of a CDMA radio receiver. A channel impulse response is estimated for a received signal containing plural paths, each path having a corresponding path delay. A search window defines a delay profile that contains the plural paths of the received signal. A mean or average delay is calculated for the estimated channel impulse response (CIR), and an error is determined between the mean CIR delay and a desired or target delay position of the Cir. search window. An adjustment is made to reduce that error to align the targeted position of the search window and the mean CIR delay. A Doppler frequency is estimated for each path. The adjustment is made taking into account a Doppler effect caused by relative movement between the transmitter and receiver.

To synchronize spread spectrum (SS) signal with PN sequence, even when a Doppler frequency of fading is low. Delay profile combining means outputs a combined delay profile from delay profiles which are outputted from receiving units. Further, the synch chip timing which is obtained from the combined delay profile is fed commonly to receiving units for path diversity combining.

A carrier interpolation unit (a digital filter) performs interpolation processing of SP signal in the frequency domain. An IFFT circuit converts a frequency-domain signal into a time-domain signal. A delay profile generation unit generates a delay profile based on an output of the IFFT circuit. The filter control unit controls a pass band of the digital filter in accordance with the delay profile. An FFT window control unit controls a position of a window to extract a calculation range of FFT in accordance with the delay profile. When delay time of multipath is larger than the guard interval, and when the reception power of the interference wave is larger than a threshold, the pass band of the digital filter is minimized.

In a mobile communication system, the tracking of synchronization is conducted in a stable state even in a multipath environment. A delay profile detector calculates a delay profile a(n) using a despread signal for each processing unit n. A delay profile averaging unit averages a(n) to produce Ave(|a(n)|<2>). A data symbol detector conducts rake combining of the despread signal using a(n) and Ave(|a(n)|<2>). According to a(n) and Ave(|a(n)|<2>, a weighting function unit calculates a representative value representing delay waves. A loop filter generates a control signal in response to the representative value. A clock controller controls a spread code generator according to the control signal.

In a computer-implemented method of adjusting a local clock at a receiver in a packet network, the local clock is generated by a phase locked loop locked to a master clock with the aid of time-stamped timing packets arriving over the network from the master clock with a packet delay distribution about a nominal delay. The timing packets are filtered to adjust for the packet delay distribution. A control input for the phase locked loop is derived from the timing packets. The amount of skew in the packet delay distribution about the nominal delay is determined, and the arrival times of timing packets are then selectively modified to correct for the amount of skew in the packet delay variation distribution prior to filtering the timing packets.

The radio reception section 1102 receives a received signal whose band has been restricted using a filter. The delay profile creation section 1104 creates continuous delay profiles for every midamble shift. The distortion component creation section 1106 creates start path distortion components by multiplying the power value of the start sample of each midamble shift by a coefficient of the filter. The removing section 1107 removes the start path distortion components of the following midamble shift from predetermined samples behind the delay profile of each midamble shift. The path selection section 1108 selects samples whose power value is equal to or greater than a threshold as paths from the delay profile with the start path distortion components removed as paths.

A CDMA receiving apparatus includes a searcher section, a finger section, a RAKE synthesizing section and a decoding section. The searcher section has a protection path memory, generates a delay profile from a reception signal, and finds peaks from the delay profile based on a variable peak level reference threshold value and a variable noise level reference threshold value which are determined based on the delay profile. Also, the searcher section reads out protection path data in a previous cycle from the protection path memory, and determines timings of valid paths based on timing of the found peaks and protection path timings of the read out protection path data. The finger section detects a signal from the reception signal for every path in response to the valid path timings. The RAKE synthesizing section carries out RAKE synthesis to the detected signals to produce a RAKE synthesis signal. The decoding section decodes the RAKE synthesis signal.

A radio terminal that receives signals from a plurality of radio stations to calculate its current position has: interference canceling means for canceling each interference signal from the plurality of received signals; a plurality of delay profile generating means for generating delay profiles of the plurality of interference-canceled received signals with use of respective corresponding codes; and position calculating means for calculating its current position, which is a signal receiving point, with use of the plurality of delay profiles, whereby advantageously reducing the capacity of a memory mounted in the mobile terminal while the position calculation is speeded up