Frequency and time synchronisation of an ofdm receiver by means of maximum likelihood decoding

Method according to one of the preceding claims, characterised in that

• the coding of the OFDM signal is chosen in such a way and a decoder of such a kind is used to determine the quality criterion that the decoder can carry out full decoding for each frequency interval.

Method according to one of the preceding claims, characterised in that

• the OFDM signal is coded according to a woven code consisting of the linking of an outer and an inner convolutional code.

Method according to one of the preceding claims, characterised in that,

• for frequency synchronisation, the OFDM signal is multiplied by a complex oscillation corresponding to the difference between the nominal frequency value (fo) and the frequency value (fx) determined via the best quality criterion.

Method according to one of the preceding claims, characterised in that,

• for synchronisation of the receiver, at the start of a transmission or periodically or aperiodically during the transmission by the sender during a frequency interval a synchronisation sequence in the form of a special bit pattern is transmitted and with it the best quality criterion is determined.

Method according to one of the preceding claims, characterised in that,

• before detection of the best quality criterion, with the aid of the pilot signals transmitted in the OFDM signal the transmission function of the transmission channel is estimated for each carrier of the OFDM signal and the OFDM signal is equalised as a function thereof.

Method according to one of the preceding claims, characterised in that,

• after the first synchronisation of the receiver, in the tracking phase the two-dimensional search for the best quality criterion is repeated within a reduced frequency and time search area and the frequency and time values of the best quality criterion gained therefrom are supplied for frequency tracking or time synchronisation via an adaptive filter in each case.

Method according to one of the preceding claims, characterised in that,

• instead of the two-dimensional search, only one search is carried out, either in the time or the frequency area.