초록 ▼

A method is described for temporally aligning a received symbol that is transmitted via orthogonal channels, e.g., OFDM channels, with a reference symbol and/or an earlier received symbol. The method includes computing phases of the first symbol for the orthogonal transmission channels and comparing

A method is described for temporally aligning a received symbol that is transmitted via orthogonal channels, e.g., OFDM channels, with a reference symbol and/or an earlier received symbol. The method includes computing phases of the first symbol for the orthogonal transmission channels and comparing the computed phases of the first symbol with phases of the reference. The phases of the first symbol are successively displaced by a predetermined phase shift which depends on the channel frequency to obtain a correlation result. The temporal alignment is determined by detecting a correlation maximum based on the correlation result and used to synchronize the first symbol with the reference. The reference can also be an earlier received symbol to provide autocorrelation. The received symbols can be processed by applying a window function, e.g. a Hanning, Hamming or Blackman window. Phase correlation provides reliable time synchronization in the presence of jammers emitting narrowband signals in excess of 32 dB above the signal level.

대표청구항 ▼

[ I claim:] [1.] A method for determining a temporal alignment between a first symbol transmitted via a plurality of orthogonal transmission channels and a reference, the method comprising the steps of:determining phases of the first symbol for the orthogonal transmission channels;comparing the phas

[ I claim:] [1.] A method for determining a temporal alignment between a first symbol transmitted via a plurality of orthogonal transmission channels and a reference, the method comprising the steps of:determining phases of the first symbol for the orthogonal transmission channels;comparing the phases of the first symbol with phases of the reference to determine a correlation between the phases of the first symbol and the phases of the reference;displacing the phases of the first symbol relative to the phases of the reference by a phase displacement and repeating the comparing;choosing a phase displacement based on the correlation between the phases of the first symbol and the phases of the reference; anddetermining the temporal alignment from the chosen phase displacement.