System for near optimal joint channel estimation and data detection for COFDM systems

A system for estimating channel characteristics in a multicarrier transmission system comprising:

• means for iteratively receiving a multicarrier signal;
• means for iteratively applying Fast Fourier transformations to carriers of said multicarrier signal;
• means for iteratively estimating channel characteristics of a multicarrier channel over which said received multicarrier signal was transmitted using iterative backward processing, wherein said means for iterative backward processing further comprises:
• means for iteratively determining if a block in a frame in the received multicarrier signal is correct;
• means for iteratively decoding said block of said received signal tentatively, if said block of said received multicarrier signal is correct;
• means for iteratively calculating a tentative reference signal based on said training block, if said block of said received multicarrier signal is correct;
• means for iteratively generating a tentative estimation of channel characteristics using said tentative reference signal, if said block of said received multicarrier signal is correct;
• means for iteratively decoding said block of said received multicarrier signal, if said block of said received multicarrier signal is not correct;
• means for iteratively calculating a reference signal based on said received block, if said block of said received multicarrier signal is correct;
• means for iteratively generating an estimation of channel characteristics using said reference signal, if said block of said received multicarrier signal is not correct;
• means for iteratively decoding said transformed received multicarrier signal;
• means for iteratively decrementing block number;
• means for iteratively determining if a beginning of said frame has been reached;
• and
• means for iteratively accepting a next block of received signal if said beginning of said frame has not been reached.

A system for estimating channel characteristics in a multicarrier transmission system comprising:

• means for receiving a multicarrier signal;
• means for applying Fast Fourier transformations to carriers of said received multicarrier signal;
• means for estimating channel characteristics of a multicarrier channel over which said received multicarrier signal was transmitted concurrently using iterative processing and iterative backward processing;
• and
• means for decoding said transformed multicarrier signal.

A system for estimating channel characteristics in a multicarrier transmission system comprising:

• a plurality of Fast Fourier transformers for transforming a received multicarrier signal from a frequency domain to a time domain;
• a channel estimator connected to said plurality of said Fast Fourier transformers;
• a plurality of demodulators configured for receiving a signal which is a sum of outputs of said Fast Fourier transformers and said channel estimator;
• a maximum ratio combiner connected to said plurality of said demodulators;
• and
• a Viterbi decoder connected to said maximum ratio combiner, said Viterbi decoder further connected to said channel estimator to provide feedback input to said channel estimator.