Information processing device, receiving method, and wireless communication system

A receiving method, comprising the steps of:

• detecting, within a received signal, a preamble portion that includes a sequential waveform, and extracting a sampling timing based on the sequential waveform;
• detecting within the received signal, based on the sampling timing, a plurality of sync portion candidates that include a specific pattern, and outputting a timing signal that indicates a starting position of the sync portion;
• storing the received signal;
• imparting a delay to the received signal, such that the beginning of the sync portion is not output until the detection of the sync portion has been determined;
• computing a difference between the received signal to which the delay has been imparted and the received signal to which an additional delay time has been imparted that is equivalent to one clock cycle in Manchester code;
• sampling data once out of every two clock cycles in the Manchester code, starting from the beginning of the sync portion for which the bias has been computed;
• performing training equalization using each one of the half sampled sync portion candidates, based on the timing signal;
• comparing equalization errors for each one of the sync portion candidates for which the training equalization has been performed, and setting the candidate position with the least error;
• reading the stored received signal based on the candidate position with the least error that has been set;
• and
• subjecting to binary determination the received signal that has been read and adaptively equalized, such that the Manchester code is decoded into NRZ code.

A wireless communication system, comprising:

• a reader/writer;
• and
• an information processing device that performs non-contact communication with the reader/writer by using a carrier wave of a specified frequency,
• wherein at least one of the reader/writer and the information processing device includes
• a preamble detection portion that detects, within a received signal, a preamble portion that includes a sequential waveform, and that extracts a sampling timing based on the sequential waveform,
• a sync detection portion that, based on the sampling timing, detects within the received signal a plurality of sync portion candidates that include a specific pattern that fulfills a specified condition, and that outputs a timing signal that indicates a starting position of the sync portion,
• a storage portion that stores the received signal,
• a storage control portion that controls the storing of the received signal in the storage portion and reading of the received signal from the storage portion,
• a delay time imparting portion that imparts a delay to the received signal that the storage control portion reads from the storage portion, such that the beginning of the sync portion is not output until the detection of the sync portion by the sync detection portion has been determined,
• a bias computation portion that computes a difference between the received signal to which the delay has been imparted by the delay time imparting portion and the received signal to which an additional delay time has been imparted that is equivalent to one clock cycle in Manchester code,
• a half sampling portion that samples data once out of every two clock cycles in the Manchester code, starting from the beginning of the sync portion for which the bias has been computed by the bias computation portion,
• an adaptive equalization portion that, based on the timing signal, performs training equalization using each one of the half sampled sync portion candidates,
• an equalization performance determination portion that compares equalization errors for each one of the sync portion candidates for which the training equalization has been performed by the adaptive equalization portion, and that sets the candidate position with the least error, and
• a binary determination portion that decodes the Manchester code into NRZ code by subjecting to binary determination the received signal that has been adaptively equalized by the adaptive equalization portion,
• and
• wherein the storage control portion reads the received signal from the storage portion based on information about the candidate position with the least error that has been set by the equalization performance determination portion.