Dora S.p.a.

Stmicroelectronics S.r.l.

Daniele Veronesi

Lorenzo Guerrieri

Paola Bisaglia

Eleonora Guerrini

A method of estimating log-likelihood ratios for first and second streams of samples of a received S-FSK signal demodulated using first and second carriers includes estimating channel and noise parameters associated with first and second transmitted values for the first and second streams of samples obtained from the received S-FSK modulated signal. Current signal-to-noise ratios are estimated for current samples of the first and second streams of samples obtained from the received S-FSK modulated signal using the channel and noise parameters. The estimated current signal-to-noise ratios are compared with values of a discrete ordered set and respective pairs of consecutive values of the discrete ordered set between which the estimated current signal-to-noise ratios are comprised are identified. Log-likelihood ratios are estimated for the current samples of the first and second streams.

Method of estimating log-likelihood ratios and relative S-FSK receiver

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.

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Aosta, Italy

Daniele Veronesi