Soft input channel estimation for two-way cooperative-OFDM

We consider the channel estimation for two-way relay OFDM networks. Aiming at time-varying characteristic of doubly-selective channels, we proposed an soft input Kalman channel estimator. To take advantage of soft information provided by the decoder, we combine this the Kalman filter with Turbo equalizer, so we needn´t many pilot symbols in practice, still can ensure the algorithm performance and reduce the time delay and complexity of this algorithm, and apply it to the basis expansion channel model (BECM), changing the variable channel parameters in the period of one OFDM symbol into invariable ones.