ADSL modem apparatus, ADSL communication apparatus, and synchronization adjustment method for ADSL communication

An ADSL modem apparatus comprising:

• a retriever that retrieves a signal component of a known carrier based on an arbitrary symbol breakpoint, from a front-end of a hyperframe;
• a calculator that sequentially calculates an outer product value between a previously retrieved signal component and a currently retrieved signal component;
• a table generator that generates a first adjustment table by dividing, by N, an added value of an added average of first outer product values within two consecutive outer product values, and of an added average of second outer product values within two consecutive outer product values, the table associating each divided area with a symbol adjustment sample number;
• and
• an adjuster that adjusts the symbol breakpoint by obtaining, from the first adjustment table, a symbol adjustment sample number corresponding to a calculated outer product value.

A synchronization adjustment method for ADSL communication comprising:

• retrieving a signal component of a known carrier based on an arbitrary symbol breakpoint, from a front-end of a hyperframe;
• sequentially calculating an outer product value between a previously retrieved signal component and a currently retrieved signal component;
• and
• adjusting the symbol breakpoint according to a pattern of the outer product values.

A synchronization adjustment method of an ADSL communication comprising:

• retrieving a signal component of a known carrier based on an arbitrary symbol breakpoint, from a front-end of a hyperframe;
• sequentially calculating an outer product value between a previously retrieved signal component and a currently retrieved signal component;
• generating a first adjustment table by dividing, by N, an added value of an added average of first outer product values within two consecutive outer product values, and of an added average of second outer product values within two consecutive outer product values, the table associating each divided area with a symbol adjustment sample number;
• and
• adjusting the symbol breakpoint by obtaining, from the first adjustment table, a symbol adjustment sample number corresponding to a calculated outer product value.

A synchronization adjustment method for ADSL communication comprising:

• performing a fast Fourier transform at an ATU-R side by receiving C-PILOT1 signal transmitted from an ATU-C side, when performing communication based on ANNEX. C of ITU-T recommended G.922.1 or G.922.2;
• calculating an outer product value between A48 signal of one previous symbol and current A48 signal, the calculation being performed based on a result of the fast Fourier transform;
• and
• adjusting symbol synchronization of reception symbol from C-PILOT1 signal using the calculated outer product value.