Transmitting apparatus, receiving apparatus, communication system, transmission method, reception method, and communication method

A receiving apparatus for receiving a multi-carrier modulated signal having a pilot signal added thereto by a transmitting apparatus, wherein a number of insertions of said pilot signal in each modulation time is adaptively determined, the receiving apparatus comprising:

• an orthogonal transform circuit for
• orthogonally transforming a received signal,
• a transmission path estimation circuit for extracting said pilot signal based on an output signal of said orthogonal transform circuit and estimating a transmission path in accordance with the extracted pilot signal, and
• a data output circuit for correcting said received signal in accordance with a result of the estimated transmission path of said transmission path estimation circuit and outputting the received signal.

A communication system for transmitting and receiving a multi-carrier modulated signal produced in accordance with transmission data, comprising:

• a mapping circuit for arranging signal points with respect to said plurality of sub-carriers in accordance with a predetermined modulation method based on said transmission data,
• a pilot addition circuit for inserting a transmission path estimation pilot signal in an output signal of said mapping circuit, wherein said pilot addition circuit adaptively determines a number of insertions of said pilot signal in each modulation time,
• a first orthogonal transform circuit for orthogonally transforming an output signal of said pilot addition circuit,
• a transmission circuit for transmitting an output signal from said transmission path,
• a reception circuit for receiving a transmission signal from said transmission path,
• a second orthogonal transform circuit for orthogonally transforming a received signal received by said reception circuit,
• a transmission path estimation circuit for extracting said pilot signal based on” the output signal of said second orthogonal transform circuit and estimating the transmission path in accordance with the extracted pilot signal, and
• a data output circuit for correcting said received signal in accordance with a result of estimation of said transmission path estimation circuit and outputting data of the received signal.

A communication method for transmitting and receiving a multi-carrier modulated signal having a plurality of sub-carriers in accordance with transmission data, comprising the steps of:

• arranging signal points with respect to said plurality of sub-carriers in accordance with a predetermined modulation method based on said transmission data,
• inserting a transmission path estimation pilot signal in an output signal produced in said step of arranging in accordance with an attribute of said transmission data, wherein a number of insertions of said pilot signal in each modulation time is adaptively determined,
• orthogonally transforming a transmission signal having said pilot signal added thereto,
• transmitting said orthogonally transformed signal over a transmission path,
• receiving the transmission signal from said transmission path,
• orthogonally transforming a received signal, extracting said pilot signal based on said orthogonally transformed received signal,
• estimating the transmission path in accordance with the extracted pilot signal,
• correcting said received signal, and
• outputting the data of the received signal.