Method of determining parameters of an OFDM signal and associated receiver
View Patent ↗The invention relates to a method of determining parameters of a signal of OFDM type in a receiver comprising a tuner and a demodulator, as well as such a receiver. The method comprises the steps: (a) programming the demodulator with a particular value of the FFT mode parameter; (b) for this particular value of FFT mode parameter and a particular value of the guard interval, exhaustive variation of other parameters of the signal; (c) verification of the absence of lock-on, even temporary, of the carrier recovery loop during the phase of variation; (d) in case of absence of lock-on, repetition of the previous steps with another FFT mode; (e) storage of the configurations of parameters corresponding to temporary lock-ons; and (f) variation of the guard interval value for each of these configurations, until permanent lock-on of the carrier recovery loop is detected.
1. A method of determining parameters of a signal of OFDM type in a receiver comprising a tuner and a demodulator, the method comprising the steps of:
(a) programming the demodulator with a particular value of an FFT mode parameter;
(b) for this particular value of FFT mode parameter and a particular value of a guard interval, exhaustive variation of other parameters of the signal;
(c) verification of an absence of lock-on, even temporary, of a carrier recovery loop during a phase of variation;
(d) in case of absence of lock-on, repetition of the previous steps with another FFT mode.
2. The method according to claim 1 , wherein the parameters whose values are varied in step (b) are an inversion and a frequency shift.
3. The method according to claim 1 , wherein the method furthermore comprises the steps of:
(e) storage of configurations of parameters corresponding to temporary lock-ons, and
(f) variation of the guard interval value for each of these configurations, until permanent lock-on of the carrier recovery loop is detected.
4. The method according to claim 3 , wherein the method furthermore comprises the step of verification, for a configuration giving rise to a permanent lock-on of the carrier recovery loop, of a synchronization of at least one error correction module of an input stage of the receiver.
5. The method according to claim 1 , wherein a detection of lock-on of the carrier recovery loop is carried out by a monitoring of state bits of the demodulator.
6. A device for receiving a signal of OFDM type, the said device comprising:
a tuner;
a demodulator which is linked to the tuner;
means of programming the demodulator for a particular value of an FFT mode parameter of the signal;
means of exhaustive variation of other parameters of the signal, for this particular value of EFT mode parameter and a particular value of a guard interval;
means of verification of an absence of lock-on, even temporary, of a carrier recovery loop during a phase of variation and, in case of absence of lock-on, for repeating this process with another FFT mode.