The present invention relates to methods and arrangements in a wireless communication system supporting cyclic-prefix insertion, using a symbol sequence comprising a number of samples for transmission over a radio channel that enables the handling of very large signal delay spreads. The symbol sequence is built up by a first symbol with CP and a second symbol with CP. The second symbol is a copy of the first symbol with the samples shifted in a way that makes the two adjacent symbols with CP match in regards to the sample order. The symbol sequence may also comprise a third symbol with CP or more, where the third symbol is a copy of the second symbol and with the samples shifted in analogy with the symbol shift described above. The resulting symbol sequence will thus appear as an extended continuous symbol thanks to the precise cyclic shift that matches adjacent symbols. This allows the receiver to place its FFT window anywhere during the extended symbol, e.g. at the end of the symbol sequence thus making it possible to handle a delay spread longer than the CP duration. It also allows to place e.g. two FFT windows and to combine the extracted signal into one SNR improved signal, while still handling a longer delay spread.