Telefonaktiebolaget Lm Ericsson (publ)

Per Ola Börjesson

Antoni Fertner

Miguel Berg

Fredrik Lindqvist

Daniel Cederholm

Klas Ericson

Chenguang Lu

Stefan Höst

Per Ödling

Elmar Trojer

Ioanna Pappa

Aldebaro Klautau

Jaume Rius I Riu

Henrik Almeida

Leonardo Ramalho

Henrik Back

Axel Frank Jensen

Adam Wiå

Stefan Allevad

Jonas Gustafsson Rosenberg

Antoni Fertber

Per Mikael Ödling

Henrik Daniel Back

Stefan Alf Allevad

It is provided a method for encoding complex data. The method includes the steps of: obtaining an input signal made up of a series of numerically represented samples; determining a time frame of the input signal to process; applying a first window function on data in the time frame, resulting in first windowed data, wherein the first window function tapers sample magnitude towards the edges of the first window function; performing a windowed complex discrete Fourier-related transform on the first windowed data, resulting in frequency-domain data including a plurality of coefficients, keeping only the real part or the imaginary part of each coefficient; quantizing the frequency domain data resulting in quantized data; outputting the quantized data as encoded data; and repeating the method, wherein each subsequent iteration of the step of determining a time frame includes determining a time frame that overlaps in time with a preceding time frame.

Encoding and decoding complex data

A method performed by an encoder of a base station system, for handling a data stream for transmission over a transmission connection between a remote unit and a base unit of the base station system, the remote unit being arranged to transmit wireless signals to, and receive from, mobile stations. The method comprises quantizing a plurality of IQ samples, converting the quantized plurality of IQ samples to IQ predictions, calculating per sample a difference between the quantized plurality of IQ samples and the IQ predictions in order to create IQ prediction errors. The method further comprises quantizing the IQ predictions or the IQ prediction errors, entropy encoding the IQ prediction errors and sending the entropy encoded IQ prediction errors over the transmission connection to a decoder of the base station system. The method can be performed by a decoder.

Methods, decoder and encoder for handling a data stream for transmission between a remote unit and a base unit of a base station system

Described is a method performed by an encoder of a base station system of a wireless communication network, for handling a data stream comprising a number of consecutive IQ samples for transmission over a transmission network between a remote unit and a base unit of the base station system. The remote unit is arranged to transmit wireless signals to and receive from mobile stations, each of the number of IQ samples comprising a first number of bits. The method comprises quantizing, by a quantizer, the IQ samples or IQ prediction errors of the IQ samples with a second number of bits, wherein an amplitude range of the quantizer for the second number of bits is variable and set based on an acceptable signal quality value, entropy encoding the quantized IQ samples or IQ prediction errors applying a first entropy encoding dictionary out of a plurality of entropy encoding dictionaries, based on the set amplitude range of the quantizer, and transmitting, to a decoder, the entropy encoded and quantized IQ samples or IQ prediction errors over the transmission network.

Methods, encoder and decoder for handling a data stream for transmission between a remote unit and a base unit of a base station system

The present disclosure relates to methods and devices for communication systems comprising an electrically conductive line. The disclosure proposes a method in a line estimation device for determining termination characteristics of an electrically conductive line in a communication system. The method comprises outputting a test signal to the line, wherein the test signal is a wideband test signal with a bandwidth arranged to provide an adequate measurement time-resolution. The method further comprises receiving reflections from impedance discontinuities of the line in response to the test signal. The method also comprises forming a trace of the reflections. The method additionally comprises identifying at least one anomaly in the trace of reflections. The method yet further comprises determining termination characteristics of the line based on characteristics of the trace before and after the identified at least one anomaly. The disclosure also relates to corresponding line estimation devices and computer programs.

Methods and devices for determining termination characteristics of an electrically conductive line

The present disclosure relates to wireline communication systems, and in particular to aspects of a method and a line estimation device for estimating a characteristic impedance of a section of a transmission medium. The method comprises determining, by a test equipment having a test port with known impedance Z, an Sscattering parameter vector S[f] of the transmission medium, indexed by frequency f. The method also comprises generating, based on Zand S[f], a model of reflection in the transmission medium corresponding to an observation of the transmission medium via a test port having a test impedance Z, and also estimating the characteristic impedance of the section as a value of Zwhich minimizes a difference between a reflection value of the model of reflection and a respective target reflection value of the section.

Estimation of impedances in a transmission medium

The present disclosure relates to determining parameters in a model of a transmission line. For determining the parameters, reflection coefficient defining data and the total capacitance of the transmission line are obtained. Further, true reflection coefficients obtained through the reflection coefficient defining data are applied in an objective function for the line. The objective function for the line is a sum of error signals and each error signal is the difference between a model value of a reflection coefficient and a corresponding true reflection coefficient. Further, the objective function is minimized by utilizing gradients of the objective function with respect to the transmission line parameters to be determined. A capacitive length is employed and at least two further transmission line parameters are determined as combinations of a basic resistive transmission line parameter, a basic capacitive transmission line parameter and a basic inductive transmission line parameter of the transmission line model.

Transmission line parameter determination

A method and a test device for determining communication characteristics of a metal cable suitable for use in a communication system are provided. The method comprises transmitting a wideband test signal on the metal cable; receiving a reflected signal as a result of the wideband test signal; and determining an interval of the reflected signal to be analyzed, the interval corresponding to a part of the cable length. The method further comprises approximating the reflected signal within the interval by a regression model; and determining characteristics of the metal cable based on the regression model.

Test device and a method for determining communication characteristics of a metal cable

The invention relates to a multi-carrier method in a measurement device for improving reach of a measurement, said method comprising: transmitting a first signal in a sequence, measuring a response to said first signal, calculating a first transfer function for frequency of each modulated subcarrier in the first signal, transmitting a second signal of the sequence, wherein at least one subcarrier in the second signal has modulation different from that of the subcarriers in the first signal, measuring a response to said second signal, calculating a second transfer function for frequency of each modulated subcarrier in the second signal, said second transfer function comprising for each frequency a thereto associated second distortion component, calculating a mean value of all first and second transfer functions. The invention further relates to a measurement device for performing said method.

Multi-carrier method in a measurement device

Method and arrangement in a telecommunication system for estimating frequency dependent resistance of a transmission line. Insertion loss per length unit of the transmission line at a first frequency is determined. Thereupon a first resistance per length unit based on the determined insertion loss per length unit of the transmission line is calculated. Effective resistance per length unit at a second frequency based on the calculated first resistance is calculated. The calculated effective resistance could be used when estimating the insertion loss for the second frequency and all frequencies of interest.

Method and arrangement in a telecommunication system for estimating frequency dependent resistance

Embodiments of the present invention relate to an arrangement for analyzing transmission line properties. Measurement data providing means provide data of a first frequency dependent line property, line property calculation arrangement with model handling means, a Hubert transform handler and line property determination means calculate said first property based on model parameters, line resistance at 0 frequency, r, a cut-off frequency, v, a line capacitance Cand a line inductance L. The line model handling means calculates the line inductance L(f) via a Hubert transform of a function of Q(f/v), wherein the function Q(f/v) relates the line resistance R(f) to ras R(f)=r&#xb7;Q(f/v). The Hilbert transform values are calculated using a parameterized closed form expression for the Hubert transform or they are tabulated. The line property determination means calculates the first property and criteria function application means uses the measured first property and the calculated first property for model parameters to find optimized numerical model parameter values.

Arrangement and method relating to analysis of transmission lines

Transmission properties of a telecommunications transmission line may be estimated with improved accuracy by numerical solution for &#x393; of Z&#xb7;j&#x3c9;^C=&#x393;coth(&#x393;). At least one curve is adapted to &#x393; solutions already obtained and a starting point for numerical solution is selected in dependence of the at least one curve and in dependence of an already obtained solution close in frequency. In a first frequency range, starting points for numerical solution may be calculated from a biquadratic equation. In a second frequency range, a line in the complex plane may be adapted to solutions already obtained and new starting points selected in dependence of the line and in dependence of the previous solution. In a third frequency range, two lines in the frequency plane may be adapted to solutions already obtained and new starting points selected in dependence of the lines.

Method for estimating transmission properties of a telecommunications transmission line

The present invention relates to a method for estimating properties of a transmission line by means of features of a noise spectrum generated by noise entering said transmission line at an intermediate location between the ends of the line. The invention provides possibility to estimate a number of properties, e.g. length of a portion of the transmission line, line attenuation of said line portion and even line termination.

Passive single-ended line test

Method, arrangement and devices for calibration of a line driving device, such as a DSLAM, having a line port. The method comprises deriving of a first parameter vector, PVinf, for example Hinf. The parameter vector PVinf is derived by performing, at a first site, an echo measurement on the line driving device while the line port on said line driving device is open. The method further comprises calibrating the line driving device based on the first parameter vector PVinf and a second parameter vector PVref, which second parameter vector is based on information on echo measurements performed on at least one reference line driving device.

Calibration of a line driving device

The present invention concerns methods for estimating one or more transmission properties of a telecommunications transmission line. Estimates of the line input impedance, Zat a frequency &#x192;, and the line capacitance &#x108; are made. An estimate is then made in dependence of &#x108;, the frequency &#x192; and a value &#x393;, where &#x393; satisfies the relationship &#x393; coth (&#x393;)=Z&#xb7;j&#x3c9;&#x108;, and &#x3c9;=2&#x3c0;&#x192;. Accuracy may be improved by least squares fitting a curve to a set of intermediate values and then generating an estimate from the coefficients of the curve.

Method for transmission line analysis

A FDR SELT measurement is made in a stop band of a DSL band plan, using a PSD allowed by the PSD mask. Further measurements may also be made in an adjacent pass band and further bands, and the results combined to create a wide-band measurement result. When transformed into the time domain (e.g. by inverse Fourier transform to produce the line impulse response) greater resolution in time (and hence greater spatial resolution) is achieved. In order to compensate for AGC calibration errors measurements using different AGC steps may be scaled to fit smoothly to each other. If measurements overlap, measurement results in the region of overlap may be combined in various ways to limit the influence of noise and to create a smooth transition from one measurement to the next.

Growing community of inventors

Lund, Sweden

Per Ola Börjesson