Stmicroelectronics S.r.l.

Telecom Italia S.p.a.

Telecon Italia S.p.a.

Andrea Finotello

Bruno Melis

Alfredo Ruscitto

Donato Ettorre

Maurizio Graziano

Stefano Valle

Lorena Simoni

Alessandro Ossoli

Maurizio Paolini

Maurizio Telecom Italia SpA Graziano

Bruno Telecom Italia SpA Melis

A spread spectrum digital communication receiver, of the type comprising an input memory buffer () for storing samples of an input signal (y(k)) and a code generator circuit () for generating a re-generated user code, incorporates a device () for the estimation of a channel delay profile comprises: a basic correlator () having a first input () for sequentially reading from a memory location of the input memory buffer () a plurality of samples of the input signal (y(k)), a second input () for receiving from the code generator circuit () a re-generated user code, and an output terminal for generating, by means of a correlation operation between the plurality of samples of the input signal and the regenerated user code, a first value of the channel delay profile energy (DP()); and a memory controller circuit () for addressing said the memory buffer () so that the first input () of the basic correlator () is successively fed with the content of several memory locations of the memory buffer (), each addressing operation corresponding to a new correlation operation of the basic correlator () for the computation of a new value of the channel delay profile energy (DP()).

Memory-based device and method of channel estimation in a digital communication receiver

A device for maintaining fine alignment between an incoming spread spectrum signal and a locally generated code in a digital communication receiver comprises: a delay line for storing a plurality of consecutive samples (E-E, M, L, L+) of the incoming spread spectrum signal; three digitally controlled interpolators for determining by interpolation between consecutive samples an interpolated early sample, an interpolated middle sample, and an interpolated late sample; two correlators for calculating an error signal as the difference between the energy of the symbols computed from the interpolated early and late samples; a circuit for generating a control signal for controlling the interpolation phase of the digitally controlled interpolator for the early sample, and a digital non-linear filter, for smoothing the control signal of the interpolator for the early sample, enabling the update operation of the control signal only when the absolute value of the error signal at a time instant n is smaller than the absolute value of the same error signal at a time instant n&#x2212;1.

Early-late synchronizer having reduced timing jitter

A method for the synchronization of a digital telecommunication receiver comprises the steps of:&#x2014;storing a plurality of consecutive samples E&#x2212;1, E, M, L, L+1 of an incoming spread spectrum signal in a delay line 56;&#x2014;determining by interpolation between consecutive samples of the incoming spread spectrum signal, by means of a first digitally controlled interpolator, an interpolated early sample (e) anticipating an optimal sampling time instant;&#x2014;determining by interpolation between consecutive samples of the incoming spread spectrum signal, by means of a second digitally controlled interpolator, an interpolated middle sample (m) corresponding to the optimal sampling time instant;&#x2014;determining by interpolation between consecutive samples of the incoming spread spectrum signal, by means of a third digitally controlled interpolator, an interpolated late sample (l) delayed with respect to the optimal sampling time instant;&#x2014;calculating an error signal &#x3be; as the difference between the energy of the symbols computed from the interpolated early sample (e) and the interpolated late (l) sample;&#x2014;extracting the sign of the error signal &#x3be;&#x2014;accumulating the sign of the error signal &#x3be; for the generation of control signals S, S, Sfor controlling the interpolation phases of the digitally controlled interpolators used for determining the interpolated early (e), middle (m) and late (l) samples. The accumulated value has a positive saturation value of +4 and a negative saturation value of 4.

Method and device for fine synchronization of a digital telecommunication receiver

A method for the estimation of the transfer function of a transmission channel in a receiving system of UMTS type envisages the computation of a plurality of channel coefficients, included among known channel coefficients corresponding to pilot symbols, through the reiteration of an interpolation algorithm, capable of calculating an intermediate point (Z, f(Z)) between a first extreme and a second extreme of a determined interval, the first extreme being formed by at least two known points and the second extreme being formed by at least one known point, the intermediate point to be calculated having as abscissa (Z) the abscissa value of the mean point between the points defining the interval rounded off to the integer closest to the first extreme, and having as ordinate (F(Z)) the arithmetic average between the ordinate of the known point of the second extreme and the ordinate of a point, chosen between the two known points of the first extreme, having a distance from the intermediate point equal to the distance between the intermediate point and the known point of the second extreme.

Interpolation for use in channel estimation

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Turin, Italy

Andrea Finotello