Adaptive equalization apparatus and method

An adaptive equalization method comprising the steps of

• generating a sync word signal sequence which is the same as a sync word transmitted from a transmitter;
• calculating a correlation between a received signal and the sync word signal and delivering a resulting correlation value as a correlation output signal;
• determining a mean value and a variance of the correlation output signal in a given time span while shifting the time span in a time domain and determining K variances (where K is an integer equal to or greater than 1) at timings where corresponding mean values are greater than a threshold;
• generating a symbol sync timing signal on the basis of said timings;
• sampling the received signal using said symbol sync timing signal;
• and applying an adaptive equalization to the sampled received signal to determine a decided symbol.

An adaptive equalization apparatus comprising

• a sync word generator for delivering a sync word which is the same as a sync word transmitted from a transmitter;
• a correlator for receiving the sync word signal and a received signal as inputs, for calculating a correlation between the received signal and the sync word signal and for delivering a correlation value as a correlation output signal;
• a power measuring unit for receiving the correlation output signal as an input and for determining a power sum of the correlation output signal in a given time span while shifting the time span in a time domain;
• a first symbol sync timing signal generator for selecting L timings whose L power sums are obtained (where L is an integer equal to or greater than 1) by comparing power sums calculated by the power measuring unit with a given reference and for generating and delivering symbol sync timing signals on the basis of the selected L timings;
• a second symbol sync timing generator for generating symbol sync timing signals on a basis of a timing for a 1st arrival path;
• a timing selector for switching a timing between the symbol sync timing signal from the first symbol sync timing generator and the symbol sync timing signal from the second symbol sync timing generator adaptively in accordance with a quality of communication;
• a sampler for sampling the received signal using the symbol sync timing signal selected by the timing selector;
• and an adaptive equalizer for receiving the sampled received signal and for applying an adaptive equalization thereto to deliver a decided symbol.

An adaptive equalization method comprising the steps of

• generating a sync word signal sequence which is the same as a sync word transmitted from a transmitter;
• calculating a correlation between a received signal and the sync word signal and delivering a resulting correlation value as a correlation output signal;
• calculating a power sum of the correlation output signal within a given time span while shifting the time span in a time domain;
• selecting L power sums (where L is an integer equal to or greater than 1) by comparing the power sums with a given reference, and generating a first symbol sync timing signal on the basis of a timing where one of the selected power sums is obtained;
• generating a second symbol sync timing signal on a basis of a timing for a 1st arrival path;
• adaptively switching between the first symbol sync timing signal and the second symbol sync timing signal in accordance with a quality of communication to provide a symbol sync timing signal which is used in sampling the received signal;
• sampling the received signal using the symbol sync timing signal;
• and applying an adaptive equalization to the sampled received signals to determine a decided symbol.