System and method for blind channel estimation and coherent differential equalization in an orthogonal frequency division multiplexing (OFDM) receiver

A wireless receiver comprising:

• a front end circuit to receive and process radio frequency signals into frequency domain data;
• a detector circuit configured, based on the frequency domain data, to determine a channel estimate for a first frequency carrier using a first channel estimate for the first frequency carrier and one or more other channel estimates, each of the one or more other channel estimates for one of one or more neighboring frequency carriers within an evaluation window, the detector circuit further configured to determine a soft decision for the first frequency carrier using the channel estimate for the first frequency carrier, the detector circuit including a channel estimator circuit configured to generate a plurality of channel estimates for the first frequency carrier, the plurality of channel estimates including the first channel estimate, and a channel estimation smoother configured to determine the channel estimate for the first frequency carrier using the first channel estimate and the one or more other channel estimates;
• and
• a decoder circuit coupled to the detector circuit and configured to decode encoded message information in the frequency domain data using the soft decision.

A wireless receiver comprising:

• a front end circuit to receive and process radio frequency signals into frequency domain data;
• a detector circuit configured, based on the frequency domain data, to determine a channel estimate for a first frequency carrier using a first channel estimate for the first frequency carrier and one or more other channel estimates, each of the one or more other channel estimates for one of one or more neighboring frequency carriers within an evaluation window, the detector circuit further configured to determine a soft decision for the first frequency carrier using the channel estimate for the first frequency carrier;
• and
• a decoder circuit coupled to the detector circuit and configured to decode encoded message information in the frequency domain data using the soft decision the decoder circuit configured to perform coherent demodulation for a differentially encoded quadrature phase shift keying orthogonal frequency division multiplexing symbol.

A method of operating a wireless receiver comprising:

• receiving radio frequency signals with a front end circuit of the wireless receiver, and converting the radio frequency signals into frequency domain data;
• determining, with processing circuitry of the wireless receiver, based on the frequency domain data, a channel estimate for a first frequency carrier using a first channel estimate for the first frequency carrier and one or more other channel estimates, each of the one or more other channel estimates for one of one or more neighboring frequency carriers within an evaluation window;
• determining, with the processing circuitry, a log likelihood ratio for the first frequency carrier using the channel estimate for the first frequency carrier;
• and
• performing coherent demodulation for a differentially encoded quadrature phase shift keying orthogonal frequency division multiplexing symbol to decode encoded message information in the frequency domain data using the log likelihood ratio.

A wireless receiver comprising:

• a front end circuit to receive and process radio frequency signals into frequency domain data;
• a detector circuit configured, based on the frequency domain data, to determine a plurality of channel estimates within an evaluation window having a plurality of frequency carriers including a first frequency carrier, each of the plurality of channel estimates for one of the plurality of frequency carriers, the detector circuit further configured to calculate a plurality of metrics for each of the plurality of frequency carriers using at least some of the plurality of channel estimates, and to determine a soft decision for the first frequency carrier based at least in part on the plurality of metrics;
• and
• a decoder circuit coupled to the detector circuit to decode encoded message information in the frequency domain data using the soft decision for the first frequency carrier, the decoder circuit configured to perform coherent demodulation for a differentially encoded quadrature phase shift keying orthogonal frequency division multiplexing symbol.

A wireless receiver comprising:

• a front end circuit to receive and process radio frequency signals into frequency domain data;
• a detector circuit configured, based on the frequency domain data, to determine a plurality of channel estimates within an evaluation window having a plurality of frequency carriers including a first frequency carrier, each of the plurality of channel estimates for one of the plurality of frequency carriers, the detector circuit further configured to calculate a plurality of metrics for each of the plurality of frequency carriers using at least some of the plurality of channel estimates, and to determine a soft decision for the first frequency carrier based at least in part on the plurality of metrics;
• and
• a decoder circuit coupled to the detector circuit to decode encoded message information in the frequency domain data using the soft decision for the first frequency carrier the detector circuit further configured to determine a first channel estimate for the first frequency carrier by calculating an average of an initial channel estimate for the first frequency carrier and initial channel estimates for a plurality of other frequency carriers of the plurality of frequency carriers.