Abstract: Noise in a communication channel is estimated by, in the absence of transmitted information packets, obtaining a plurality of sets of signal samples, and estimating noise power levels associated with the sets of signal samples and allotted to respective noise power classes. In the presence of at least one transmitted information packet, an information packet power level is estimated. A set of signal-to-noise ratios computed between the information packet power level and the noise power levels in the respective noise power classes are compared against a signal-to-noise threshold and partitioned into a first subset and a second subset of signal-to-noise ratios failing to exceed/exceeding, respectively, the threshold. One or more resulting impulsive noise parameters are computed as a function of impulsive noise parameters indicative of noise power levels in the signal-to-noise ratios in the first subset while disregarding impulsive noise parameters indicative of noise power levels in the second subset.

Abstract: Noise in a communication channel is estimated by, in the absence of transmitted information packets, obtaining a plurality of sets of signal samples, and estimating noise power levels associated with the sets of signal samples and allotted to respective noise power classes. In the presence of at least one transmitted information packet, an information packet power level is estimated. A set of signal-to-noise ratios computed between the information packet power level and the noise power levels in the respective noise power classes are compared against a signal-to-noise threshold and partitioned into a first subset and a second subset of signal-to-noise ratios failing to exceed/exceeding, respectively, the threshold. One or more resulting impulsive noise parameters are computed as a function of impulsive noise parameters indicative of noise power levels in the signal-to-noise ratios in the first subset while disregarding impulsive noise parameters indicative of noise power levels in the second subset.

Abstract: A method of transmitting symbols of a digital transmission constellation from a set thereof, ordered from a smallest to a greatest number of bits per symbol, may include identifying a first constellation from the set that is configured to communicate with a threshold error rate and has a greatest signal-to-noise ratio smaller than a signal-to-noise ratio of a received signal. The method may also include identifying a second constellation from the set that corresponds to a constellation with a number of bits per symbol immediately greater than the first constellation. The method may further include determining first and second probabilities of use of the first and second constellations that would generate an expected number of erroneous bits corresponding to the threshold error rate. The method may further include transmitting a symbol with a constellation selected randomly between the first and second constellations according to the first and second probabilities, respectively.

Abstract: An OFDM receiver includes a sampling circuit configured to sample an incoming signal received through a transmission channel and an estimation circuit configured to receive samples of the incoming signal and to estimate transmission channel response and eventual differences of synchronization offsets introduced at a receiver side. An equalizer may be coupled to the estimation circuit and configured to compensate an effect of the transmission channel response and of the differences of synchronization offsets on the received samples and to generate equalized samples. An OFDM detector may be configured to generate a stream of demodulated digital symbols based upon the equalized samples.

Abstract: A method of estimating a signal-to-noise ratio from a received M-DPSK modulated signal, comprising a sequence of N known symbols, based on a division of the known symbols N and of N samples of the received signal at the output of the channel into a number of blocks B of length L with B greater than one.

Abstract: A method for loading bits over a set of subcarriers of a multiple-carrier communications system comprises the operation of associating with the subcarriers respective numbers of bits chosen from among a plurality of available constellations. The method envisages definition of a performance target for the system and execution of bit loading, guaranteeing the aforesaid target on a plurality of subcarriers. The performance target can be a target error rate, such as a bit-error rate (BER), or else be transferred into a constraint, such as, for example, a threshold, in a metric of log-likelihood ratios (LLRs). In this case, there is preferably envisaged application to the signals received within the multiple-carrier system a function that estimates a signal to noise ratio on each sub-carrier. The aforesaid metric of log-likelihood ratios (LLRs) is hence defined as a function of said signal to noise ratios.

Abstract: A method of transmitting symbols of a digital transmission constellation from a set thereof, ordered from a smallest to a greatest number of bits per symbol, may include identifying a first constellation from the set that is configured to communicate with a threshold error rate and has a greatest signal-to-noise ratio smaller than a signal-to-noise ratio of a received signal. The method may also include identifying a second constellation from the set that corresponds to a constellation with a number of bits per symbol immediately greater than the first constellation. The method may further include determining first and second probabilities of use of the first and second constellations that would generate an expected number of erroneous bits corresponding to the threshold error rate. The method may further include transmitting a symbol with a constellation selected randomly between the first and second constellations according to the first and second probabilities, respectively.

Abstract: An OFDM receiver includes a sampling circuit configured to sample an incoming signal received through a transmission channel and an estimation circuit configured to receive samples of the incoming signal and to estimate transmission channel response and eventual differences of synchronization offsets introduced at a receiver side. An equalizer may be coupled to the estimation circuit and configured to compensate an effect of the transmission channel response and of the differences of synchronization offsets on the received samples and to generate equalized samples. An OFDM detector may be configured to generate a stream of demodulated digital symbols based upon the equalized samples.

Abstract: A method of estimating a signal-to-noise ratio from a received M-DPSK modulated signal, comprising a sequence of N known symbols, based on a division of the known symbols N and of N samples of the received signal at the output of the channel into a number of blocks B of length L with B greater than one.

Abstract: A method for loading bits over a set of subcarriers of a multiple-carrier communications system comprises the operation of associating with the subcarriers respective numbers of bits chosen from among a plurality of available constellations. The method envisages definition of a performance target for the system and execution of bit loading, guaranteeing the aforesaid target on a plurality of subcarriers. The performance target can be a target error rate, such as a bit-error rate (BER), or else be transferred into a constraint, such as, for example, a threshold, in a metric of log-likelihood ratios (LLRs). In this case, there is preferably envisaged application to the signals received within the multiple-carrier system a function that estimates a signal to noise ratio on each sub-carrier. The aforesaid metric of log-likelihood ratios (LLRs) is hence defined as a function of said signal to noise ratios.