Communication network system, and transmission/reception apparatus, method and integrated circuit for use therein

A transmitting method, executed by a transmitting apparatus, for transmitting input data to a receiving apparatus via a transmission path, the transmitting method comprising:

• generating a first training signal and a second training signal by modulating a plurality of carriers respectively having different frequencies for estimating transmission conditions on a channel that is fluctuating cyclically;
• controlling a timing of transmission of the second training signal such that a time interval between transmission of the first training signal and transmission of the second training signal is asynchronous to a cycle of channel fluctuation;
• transmitting the first training signal and the second training signal to the receiving apparatus;
• receiving, from the receiving apparatus, a first channel estimation result including a first tone map which indicates a modulation method for each carrier and is determined based on the first training signal, and a second channel estimation result including a second tone map which indicates a modulation method for each carrier and is determined based on the second'training signal;
• storing the first tone map and the second tone map;
• and
• transmitting the input data by modulating the plurality of carriers according to the first tone map or the second tone map stored in the storing step.

An integrated circuit to be used in a transmitting apparatus for transmitting input data to a receiving apparatus via a transmission path, comprising:

• a transmitting section configured to generate a first training signal and a second training signal by modulating a plurality of carriers respectively having different frequencies and configured to transmit the first training signal and the second training signal to the receiving apparatus for estimating transmission conditions on a channel that is fluctuating cyclically;
• a receiving section configured to receive, from the receiving apparatus, a first channel estimation result including a first tone map which indicates a modulation method for each carrier and is determined based on the first training signal, and a second channel estimation result including a second tone map which indicates a modulation method for each carrier and is determined based on the second training signal;
• a storage section configured to store the first tone map and the second tone map;
• and
• a control section configured to control a timing of transmission of the second training signal such that a time interval between transmission of the first training signal and transmission of the second training signal is asynchronous to a cycle of channel fluctuation,
• wherein the transmitting section transmits the input data by modulating the plurality of carriers according to the first tone map or the second tone map stored in the storage section.