Method and apparatus for channel estimation

A channel estimation method comprising:

• receiving a time-domain multi-carrier signal representing a channel training sequence;
• performing a cyclic convolution function on the training sequence;
• extracting a time window within which the received signal has an optimum amount of energy;
• and
• multiplying a weighing matrix with the convolved training sequence to arrive at channel estimates, wherein, the multiplying occurs during the time window extracted by the extracting step.

A method for communicating data between a transmitter and a receiver separated by a channel, the method comprising:

• at the transmitter end:
• generating a plurality of modulated sub-carrier signals based on the data;
• transforming the plurality of modulated sub-carrier signals into a plurality of time-domain signals;
• transmitting the plurality of time-domain signals across the channel as a multi-carrier signal;
• and
• at the receiver end:
• receiving the multi-carrier signal in time domain;
• estimating a channel transfer function using a subset of the multi-carrier signal in time-domain to provide a plurality of channel estimates;
• transforming the multi-carrier signal and the plurality of channel estimates from time-domain into frequency-domain to provide a transformed multi-carrier signal and a plurality of transformed channel estimates;
• and
• compensating the transformed multi-carrier signal for channel effects using the plurality of transformed channel estimates.

In a multi-carrier data communication system, a receiver comprising:

• a channel estimator that receives a multi-carrier time-domain signal at an input and generates a plurality of channel estimates at an output;
• a time-domain to frequency-domain transform unit coupled to the output of the channel estimator and configured to convert the multi-carrier time-domain signal and the channel estimates from time-domain into frequency-domain;
• and
• an equalizer coupled to an output of the transform unit and configured to compensate the multi-carrier signal for channel effects using the channel estimates.

A multi-carrier data communication system comprising:

• a transmitter including:
• a modulator/deserializer configured to convert an input data stream into a plurality of modulated sub-carrier signals;
• a frequency-domain to time-domain converter having an input coupled to the modulator/deserializer and configured to transform the plurality of modulated sub-carrier signals from frequency-domain into time-domain at an output;
• a guard period insertion block coupled to the frequency-domain to time-domain converter and configured to insert a guard period in the output of the frequency-domain to time-domain converter;
• a serializer coupled to an output of the guard period insertion block and configured to perform a parallel to serial conversion to provide a digital multi-carrier signal;
• and
• a digital-to-analog converter coupled to the serializer and configured to convert the digital multi-carrier signal into an analog multi-carrier signal and to transmit the analog multi-carrier signal across a channel;
• a receiver including:
• an analog-to-digital converter coupled to receive the analog multi-carrier signal and configured to convert the analog multi-carrier signal into a digital multi-carrier signal;
• a deserializer coupled to the analog-to-digital converter and configured to convert the digital multi-carrier signal into a plurality of parallel signals;
• a channel estimator coupled to the deserializer and configured to derive channel estimates using a training sequence embedded in the analog multi-carrier signal;
• a guard period removal block coupled to an output of the channel estimator and configured to remove the guard period;
• a time-domain to frequency-domain converter coupled to an output of the guard period removal block and operating to provide a parallel plurality of received sub-carrier signals;
• an equalizer coupled to the time-domain to frequency-domain converter and configured to equalize the parallel plurality of received sub-carrier signals using the channel estimates;
• and
• a serializer/demodulator coupled to an output of the equalizer and configured to generate an output data stream.