Double Blind Channels Estimation for Interference Cancellation of Multicarrier Transmissions

This article deals with the simultaneous reception, in the same frequency band, of two OFDM symbols, received at the same power level and therefore interfering very strongly with each other. The receiver has only one antenna and no pilot signal is available. It is therefore necessary to estimate the two impulse responses of the two propagation channels in a completely blind manner and then to estimate the two transmitted symbol streams. The receiver knows the modulations used by the two sources and the two OFDM symbols received are synchronized with an uncertainty of the order of the size of the cyclic prefix of the waveform. The paper presents a 10-step algorithm that can separate the two signals and estimate the symbols transmitted by the two sources. The algorithm uses a set of methods ranging from higher orders statistics to iterative estimation and to self-deconvolution.