Method and apparatus for generating pilot tone in orthogonal frequency division multiplexing access system, and method and apparatus for estimating channel using it

A transmitter in a wireless communication system, comprising:

• a symbol mapping unit configured to generate a signal with a sequence;
• a pilot symbol inserting unit configured to:
• select an orthogonal sequence from a set of orthogonal sequences represented by an n×n matrix, n being a positive integer, and
• generate a pilot with the orthogonal sequence,
• wherein rows of the matrix constitute the orthogonal sequences;
• and
• an RF processing unit configured to transmit the signal in an Orthogonal Frequency Division Multiplexing (OFDM) symbol of a resource block, and transmit the pilot in another OFDM symbol of the resource block, wherein:
• the resource block comprises a plurality of subcarriers in a frequency domain and a plurality of OFDM symbols in a time domain, respectively,
• any two subcarriers on which the pilot is transmitted are either the same subcarrier or non-adjacent subcarriers in the frequency domain and are respectively on OFDM symbols that are either non-adjacent OFDM symbols or the same OFDM symbol in the time domain within the resource block,
• at least two subcarriers on which the pilot is transmitted are on one of the plurality of OFDM symbols of the resource block, and
• the pilot is transmitted:
• on at least three of the plurality of OFDM symbols of the resource block, and
• on subcarriers that are either the same subcarrier in the frequency domain or separated in the frequency domain by at least two subcarriers not containing the pilot within the resource block, and that include a subcarrier of a highest frequency and a subcarrier of a lowest frequency in the frequency domain respectively on the at least three OFDM symbols within the resource block.

A method of transmitting signals in a wireless communication system, comprising:

• transmitting information about an orthogonal sequence from a set of orthogonal sequences represented by an n×n matrix, n being a positive integer, wherein rows of the matrix constitute the orthogonal sequences;
• generating a signal with a sequence;
• generating a pilot with the orthogonal sequence;
• and
• transmitting the signal in an Orthogonal Frequency Division Multiplexing (OFDM) symbol of a resource block, and transmitting the pilot in another OFDM symbol of the resource block, wherein:
• the resource block comprises a plurality of subcarriers in a frequency domain and a plurality of OFDM symbols in a time domain, respectively,
• any two subcarriers on which the pilot is transmitted are either the same subcarrier or non-adjacent subcarriers in the frequency domain and are respectively on OFDM symbols that are either non-adjacent OFDM symbols or the same OFDM symbol in the time domain within the resource block,
• at least two subcarriers on which the pilot is transmitted are on one of the plurality of OFDM symbols of the resource block, and
• the pilot is transmitted:
• on at least three of the plurality of OFDM symbols of the resource block, and
• on subcarriers that are either the same subcarrier in the frequency domain or separated in the frequency domain by at least two subcarriers not containing the pilot within the resource block, and that include a subcarrier of a highest frequency and a subcarrier of a lowest frequency in the frequency domain respectively on the at least three OFDM symbols within the resource block.

A transmitter in a wireless communication system, comprising:

• a symbol mapping unit configured to generate a signal with a sequence;
• a pilot symbol inserting unit configured to generate a pilot with an orthogonal sequence from a set of orthogonal sequences represented by an n×n matrix, n being a positive integer, wherein rows of the matrix constitute the orthogonal sequences;
• and
• an RF processing unit configured to:
• transmit information about the orthogonal sequence from the set of orthogonal sequences, and
• transmit the signal in an Orthogonal Frequency Division Multiplexing (OFDM) symbol of a resource block, and transmit the pilot in another OFDM symbol of the resource block, wherein:
• the resource block comprises a plurality of subcarriers in a frequency domain and a plurality of OFDM symbols in a time domain, respectively,
• any two subcarriers on which the pilot is transmitted are either the same subcarrier or non-adjacent subcarriers in the frequency domain and are respectively on OFDM symbols that are either non-adjacent OFDM symbols or the same OFDM symbol in the time domain within the resource block,
• at least two subcarriers on which the pilot is transmitted are on one of the plurality of OFDM symbols of the resource block, and
• the pilot is transmitted:
• on at least three of the plurality of OFDM symbols of the resource block, and
• on subcarriers that are either the same subcarrier in the frequency domain or separated in the frequency domain by at least two subcarriers not containing the pilot within the resource block, and that include a subcarrier of a highest frequency and a subcarrier of a lowest frequency in the frequency domain respectively on the at least three OFDM symbols within the resource block.