A successive minimum-mean-square-error OFDM-data-symbol cancellation scheme for channel estimation in the Pseudo-Random-Postfix OFDM context
Original Publication Date: 2004-Sep-08
Included in the Prior Art Database: 2004-Sep-08
This contribution proposes an iterative channel impulse response (CIR) estimation scheme in the context of the Pseudo-Random-Postfix OFDM (PRP-OFDM) modulation. While conventional techniques eliminate interference on the CIR estimates by simple mean value calculation, the new proposal uses soft decoder outputs in order to perform iterative interference cancellation. In a typical example for QAM-64 constellations, the mean-square-error (MSE) of the CIR estimates is improved by approx. 12dB after three iterations. Based on PRP-OFDM postfixes only, it is thus possible to perform channel estimation for higher order constellations (QAM-64 and higher) with an initial CIR estimation over a small observation window (for QAM-64 typically 30 to 40 OFDM symbols). Any loss in throughput due to additional redundancy for CIR estimation purposes, e.g. pilot tones, learning symbols, etc. is avoided at the cost of an increase in decoding complexity.