Alcatel N.v.

Alcatel Radiotelephone

Lydie Desperben

Ouelid Abdesselem

Luc Dartois

Emmanuel Rousseau

Christian Trinh Van

Pierre-Francois Kamanou

Marie-Pierre Popu

A device is provided for selecting reception signals as a function of their power, the reception signals being identified by their frequency and being structured into frames made up by a number of time slots. Power is calculated for each one of the signals being explored using as a basis measurements carried out on several selected time slots that correspond to the signal during a series of repetitive analysis periods. The selected time slot of the first signal explored during an analysis period bearing a number less than or equal to the number of time slots that make up a frame occupies a different position in the frame from the positions that it occupied during preceding analysis periods.

Device for selecting reception signals as a function of their power

A digital signal is equalized, for example in cellular radio systems, to combat intersymbol interference. Each sample received is associated with an estimated symbol representing the transmitted symbol. The equalization process comprises an iterative stage of intersymbol interference elimination, each iteration comprising for each sample of a set of received samples whose value has not been determined during a previous iteration: comparing said sample with at least one confidence threshold and if said sample exceeds any of said thresholds: associating with said sample an estimated symbol whose value depends on said threshold exceeded, the value of said sample being then determined; and eliminating the intersymbol interference caused to other samples belonging to said set of received samples by said estimated symbol.

Adaptive equalization method reducing intersymbol interference, receive

A device for recovering an original bit stream from a received bit stream by processing the received bit stream in accordance with the Viterbi algorithm comprises an operator to establish the maximal metric of rank r of the state E.sub.j denoted Met.sub.r (E.sub.j) for r greater than n and the (r-n) th bit of the bit stream corresponding to the metric from input values which are maximal metrics of rank r-1 of states E.sub.2k and E.sub.2k+1 denoted Met.sub.r-1 (E.sub.2k) and Met.sub.r-1 (E.sub.2k+1) and the conditional probabilities related to the states E.sub.2k, E.sub.2k+1) that the r-th bit of the bit streams associated with these states has a determined value denoted (Pr(b(r)+0/E.sub.2k) and (Pr(b(r)=0/E.sub.2k+1) for example where k is equal to 2j for any value of j less than 2.sup.n-1 and has the value 2(j-2.sup.n-1) for any value of j greater than or equal to 2.sup.n-1, so that Met.sub.r (E.sub.j) takes the larger of the values of the expressions Met.sub.r (E.sub.j)+(Pr (b (r)=0/E.sub.2k) and Met.sub.r-1 (E.sub.2k+1)+(Pr (b (r)=0/E.sub.2k+1).

Device for processing the Viterbi algorithm comprising a processor and a

A digital cellular radiocommunication system includes a circuit for evaluating the frequency difference between a local signal and the carrier wave of a receive signal which are close together in frequency, the receive signal having been subjected to phase state modulation by a modulation signal and thus having a phase that includes a transmission phase shift, a modulation phase shift corresponding to one of a plurality of phase states, and a synchronization phase shift due to the frequency difference. The circuit produces samples of the receive signal from which the transmission phase shift has been eliminated, detects the modulation phase shift of the samples in order to eliminate it, produces the mean phase of a series of samples, and produce the frequency difference on the basis of the mean phase of at least two series of samples and on the basis of the time interval between the middles of the series.

Circuit for evaluating frequency difference

The present invention relates to a measurement circuit for providing the digital value of an analog electrical signal. The digital measurement circuit for measuring an analog electrical signal produces a measurement signal (M) and includes an amplifier (1) which receives said electrical signal (I), followed by an analog-to-digital converter (2) which delivers digital data (N). The gain of the amplifier (1) is controlled by a control signal (C) and said gain can take up at least two values. The measurement circuit further includes a control unit (3) producing said control signal (C) and storing the digital data corresponding to different gain values, and includes means for producing the measurement signal (M) on the basis of said digital data (N).

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Bois Colombes, France

Lydie Desperben