Abstract: Encoded digital symbols are transmitted via a first pair of antennas and at least one second pair of antennas. The sets of symbols used for the transmission via the second pair of antennas are re-ordered temporally into subsets of symbols with respect to the symbols used for the first pair of antennas. For the first pair of antennas, there is used a signal subjected to encoding with a code-division-multiple-access code and subjected to spreading with a spreading code, and, likewise, for the second pair or pairs of antennas there are used signals subjected to encoding with respective code-division-multiple-access code and subjected to spreading with a respective spreading code. At least one between the respective code-division-multiple-access code and the respective spreading code used for the transmission via the second pair of antennas is different from the code-division-multiple-access code and from the spreading code used for the transmission via the first pair of antennas.

Abstract: Encoded digital symbols are transmitted via a first pair of antennas and at least one second pair of antennas. The sets of symbols used for the transmission via the second pair of antennas are re-ordered temporally into subsets of symbols with respect to the symbols used for the first pair of antennas. For the first pair of antennas, there is used a signal subjected to encoding with a code-division-multiple-access code and subjected to spreading with a spreading code, and, likewise, for the second pair or pairs of antennas there are used signals subjected to encoding with respective code-division-multiple-access code and subjected to spreading with a respective spreading code. At least one between the respective code-division-multiple-access code and the respective spreading code used for the transmission via the second pair of antennas is different from the code-division-multiple-access code and from the spreading code used for the transmission via the first pair of antennas.

Abstract: In order to perform, according to a received signal (r), a channel-estimation procedure and a cell-search procedure in cellular communication systems, there are executed at least one first operation of correlation of said received signal (r) with secondary synchronization codes (SSC) and a second operation of correlation of said received signal (r) with known midamble codes (mid, MPL, MPS), whilst said channel-estimation procedure comprises a third operation of correlation of at least part of said received signal (r) with known midamble codes (mid, MPL, MPS), said first, second, and third correlation operation being executed by sending at least part (emidamble) of said received signal (r) to an input of a correlation bank.

Abstract: Encoded digital symbols are transmitted via a first pair of antennas and at least one second pair of antennas. The sets of symbols used for the transmission via the second pair of antennas are re-ordered temporally into subsets of symbols with respect to the symbols used for the first pair of antennas. For the first pair of antennas, there is used a signal subjected to encoding with a code-division-multiple-access code and subjected to spreading with a spreading code, and, likewise, for the second pair or pairs of antennas there are used signals subjected to encoding with respective code-division-multiple-access code and subjected to spreading with a respective spreading code. At least one between the respective code-division-multiple-access code and the respective spreading code used for the transmission via the second pair of antennas is different from the code-division-multiple-access code and from the spreading code used for the transmission via the first pair of antennas.

Abstract: A method for automatic gain control of an output signal generated from an input signal includes measuring power of the output signal. Measuring power of the output signal includes setting at least one power threshold, measuring a rate of crossing of the at least one power threshold by the output signal over an observation window, and deriving from the rate of crossing a measured power of the output signal. The method further includes providing a reference power, subtracting the measured power from the reference power to obtain an error signal, and mixing the input signal with the error signal. An analog-to-digital conversion is performed on a result of the mixing to obtain a gain-controlled output signal.

Abstract: To generate the main scrambling code of order N and the secondary scrambling code of order K within the set identified by the primary scrambling code of order N, a first m-sequence and a second m-sequence are generated using Fibonacci linear feedback shift registers. The first m-sequence and the second m-sequence are modulo-2 added to form the I branch of the primary scrambling code. A first T-bit masking word and a second T-bit masking word of rank 0 are generated that correspond to the polynomial time shifts, and the intermediate taps of the X and y registers respectively chosen by the masking words are modulo-2 added so as to generate a third sequence and a fourth sequence, which are modulo-2 added together to form the Q branch of the primary scrambling code.

Abstract: A method for decoding signals with encoded symbols over a symbol interval that modulate a carrier. The method includes phase locking the signal to be decoded to obtain a phase-locked signal. The value assumed by the phase-locked signal on at least one subinterval in each symbol interval is detected. The method continues with attributing to the decoded symbol corresponding to each symbol interval a value that is a function of the value detected the subinterval. The subinterval in question can be a single subinterval located at the end of the symbol interval. Alternatively, the value assumed by the phase-locked signal on a plurality of subintervals in each symbol interval is detected, and a respective majority value of said phase-locked signal within said plurality of subintervals is identified. A value determined on the basis of the majority value is attributed to the decoded symbol corresponding to each symbol interval.

Abstract: In a first step, slot synchronization may be obtained by setting in correlation the received signal with a primary sequence, which represents the primary channel, and storing the received signal. During a second step, the correlator may be re-used for correlating the received signal with a secondary sequence corresponding to the secondary synchronization codes. The correlator may include a first filter and a second filter connected in series, which receive a first secondary sequence and a second secondary sequence, which may include Golay sequences. Architectures of parallel and serial types, as well as architectures designed for reusing further circuit parts are also disclosed. The invention is particularly applicable in mobile communication systems based upon standards such as UMTS, CDMA2000, IS95, and WBCDMA.

Abstract: To execute the cell-search procedure in a cellular communication system (such as a system based upon the 3GPP TDD standard), there are available identification codes for the second step (slot synchronization) and for the third step (identification of the scrambling codes). The identification codes are identified by a process of correlation with the received signal and are used for obtaining from a correspondence table the parameters for the execution of the second step (CD) or of the third step (SCR). The correspondence table is stored in a reduced form by the identification, according to rules of symmetry and redundancy, of subtables designed to generate the entire table by appropriate combination operations. The search procedure in the correspondence table thus reduced is conveniently modified by the introduction of the combination operations. A preferential application is in mobile communication systems based upon standards such as UMTS, CDMA2000, IS95 or WBCDMA.

Abstract: To obtain frame synchronization and identify the cell codegroup in a cellular communication system (such as a system based upon the standard 3GPP FDD), there are available the synchronization codes organized in chips or letters transmitted at the beginning of respective slots. Slot synchronization is obtained previously in a first step of the operation of cell search. During a second step, there are acquired, by means of correlation or fast Hadamard transform, the energy values corresponding to the respective individual letters with reference to the possible starting positions of the corresponding frame within the respective slot. Operating in a serial way at the end of acquisition of the aforesaid energy values of the individual letters, or else operating in parallel, the energies of the corresponding words are determined. Of these energies only the maximum word-energy value and the information for the corresponding starting position are stored in a memory structure.

Abstract: Described herein is a method for parallel generating Walsh-Hadamard (WH) channelization codes and Orthogonal Variable Spreading Factor (OVSF) channelization codes, which are channelization codes formed by a plurality of strings of antipodal digits, each having a given length L and being identifiable by respective indices I formed by strings of binary digits, each having a given length N equal to the logarithm in base two of the length L of the channelization codes, the antipodal digits of the channelization codes assuming the values +1 and ?1 and the binary digits of said indices I assuming the values 0 and 1.

Abstract: Once slot synchronization has been obtained in a first step, during a second step there is acquired, by means of correlation of the received signal (r) with the synchronization codes, the information corresponding to the codegroup and to the fine slot synchronization. The synchronization codes are split into codesets. In a first step, a synchronization code identifying a corresponding codeset (CS) is identified by means of correlation and search for the maximum value of correlation energy. In a second step, the received signal (r) is correlated with the remaining codes belonging to the codeset identified. The information thus obtained, which corresponds to all the synchronization codes comprised in the codeset identified, is used for obtaining frame synchronization and codegroup identification. Preferential application is in mobile communication systems based upon standards, such as UMTS, CDMA2000, IS95 or WBCDMA.

Abstract: A method is for compressing a digital image including a matrix of elements, with each element including at least one component of a different type for representing a pixel. The method includes splitting the digital image into a plurality of blocks, and calculating for each block a group of discrete cosine transform (DCT) coefficients for the components of each type, and quantizing the DCT coefficients of each group using a corresponding quantization table scaled by a gain factor for achieving a target compression factor. The method also includes further quantizing the DCT coefficients of each group using the corresponding quantization table scaled by a pre-set factor, and arranging the further quantized DCT coefficients in a zig-zig vector.

Abstract: A method is for compressing a digital image that is made up of a matrix of elements, with each element including a plurality of digital components of different types for representing a pixel. The method includes splitting the digital image into a plurality of blocks, and calculating for each block a group of DCT coefficients for the components of each type, and quantizing the DCT coefficients of each block using a corresponding quantization table scaled by a gain factor for achieving a target compression factor. The method further includes determining at least one energy measure of the digital image, and estimating the gain factor as a function of the at least one energy measure. The function is determined experimentally according to the target compression factor.

Abstract: Encoded digital symbols are transmitted via a first pair of antennas and at least one second pair of antennas. The sets of symbols used for the transmission via the second pair of antennas are re-ordered temporally into subsets of symbols with respect to the symbols used for the first pair of antennas. For the first pair of antennas, there is used a signal subjected to encoding with a code-division-multiple-access code and subjected to spreading with a spreading code, and, likewise, for the second pair or pairs of antennas there are used signals subjected to encoding with respective code-division-multiple-access code and subjected to spreading with a respective spreading code. At least one between the respective code-division-multiple-access code and the respective spreading code used for the transmission via the second pair of antennas is different from the code-division-multiple-access code and from the spreading code used for the transmission via the first pair of antennas.

Abstract: The device can be used for generating, in the framework of a CDMA communications terminal, both Walsh-Hadamard channeling codes and OVSF channeling codes. The device comprises a code generator preferably configured for generating Walsh-Hadamard codes. When the device is used for generating Walsh-Hadamard codes, the corresponding index values, applied to an input of the device, are sent to the input of the code generator. Generation of OVSF codes envisages, instead, that the corresponding indices, sent to an input of the device, undergo mapping, which enables generation, starting from the OVSF code, of the corresponding index identifying a string of symbols that is identical within the Walsh-Hadamard code. In this way each string of OVSF code symbols is generated, so producing, by means of the code generator, the generation of the identical string of symbols included in the Walsh-Hadamard code.

Abstract: In order to perform, according to a received signal (r), a channel-estimation procedure and a cell-search procedure in cellular communication systems, there are executed at least one first operation of correlation of said received signal (r) with secondary synchronization codes (SSC) and a second operation of correlation of said received signal (r) with known midamble codes (mid, MPL, MPS), whilst said channel-estimation procedure comprises a third operation of correlation of at least part of said received signal (r) with known midamble codes (mid, MPL, MPS), said first, second, and third correlation operation being executed by sending at least part (emidamble) of said received signal (r) to an input of a correlation bank.

Abstract: A method for decoding signals with encoded symbols over a symbol interval that modulate a carrier. The method includes phase locking the signal to be decoded to obtain a phase-locked signal. The value assumed by the phase-locked signal on at least one subinterval in each symbol interval is detected. The method continues with attributing to the decoded symbol corresponding to each symbol interval a value that is a function of the value detected the subinterval. The subinterval in question can be a single subinterval located at the end of the symbol interval. Alternatively, the value assumed by the phase-locked signal on a plurality of subintervals in each symbol interval is detected, and a respective majority value of said phase-locked signal within said plurality of subintervals is identified. A value determined on the basis of the majority value is attributed to the decoded symbol corresponding to each symbol interval.

Abstract: A method for automatic gain control of an output signal generated from an input signal includes measuring power of the output signal. Measuring power of the output signal includes setting at least one power threshold, measuring a rate of crossing of the at least one power threshold by the output signal over an observation window, and deriving from the rate of crossing a measured power of the output signal. The method further includes providing a reference power, subtracting the measured power from the reference power to obtain an error signal, and mixing the input signal with the error signal. An analog-to-digital conversion is performed on a result of the mixing to obtain a gain-controlled output signal.

Abstract: To execute the cell-search procedure in a cellular communication system (such as a system based upon the 3GPP TDD standard), there are available identification codes for the second step (slot synchronization) and for the third step (identification of the scrambling codes). The identification codes are identified by a process of correlation with the received signal and are used for obtaining from a correspondence table the parameters for the execution of the second step (CD) or of the third step (SCR). The correspondence table is stored in a reduced form by the identification, according to rules of symmetry and redundancy, of subtables designed to generate the entire table by appropriate combination operations. The search procedure in the correspondence table thus reduced is conveniently modified by the introduction of the combination operations. A preferential application is in mobile communication systems based upon standards such as UMTS, CDMA2000, IS95 or WBCDMA.