Adaptive low complexity channel estimation for mobile OFDM systems

摘要

Adaptive low complexity minimum mean square error (MMSE) channel estimator for OFDM systems operating over mobile channel. Complexity of the estimator is reduced by partitioning sub-carriers into windows where, window size is optimized by considering channel model mismatch error (MME). Three types of adaptive windowed MMSE (W-MMSE) estimators include: A first type, a simplified delay profile applied as channel reference model, and optimum window size adaptive to the estimated signal-to-noise ratio. A second type, a group of candidate channel reference models are considered. The receiver roughly estimates and selects current reference model from candidate group, then adapts optimum window size based on the estimated SNR and selected channel model. A third type, the current channel statistics are finely estimated and window size is iteratively optimized at receiver. The first two adaptive W-MMSE estimators are tolerant to channel model mismatch error and the third captures channel variations to realize real-time estimation.

主权项

1. A method for channel estimation of OFDM (orthogonal frequency-division multiplexing) systems operating over time-varying frequency-selective fading channels, comprising the steps of:
a) receiving an OFDM signal comprising pilot and data sub-carriers; b) providing a channel model; c) estimating the SNR (signal-to-noise ratio) of the received OFDM signal; d) determining an optimum window size that varies based on the estimated SNR and the channel model, the determined window defining each of a plurality of non-overlapping groups of the sub-carriers of the received OFDM signal; e) independently calculating the channel coefficients for each one of said groups; and f) collecting the channel coefficients calculated for all of the groups.