Patent ID: 8019005

Claim:
A communication system comprising: a transmitting apparatus; and a receiving apparatus, the transmitting apparatus comprising: a mapper configured to map a predetermined number of bits of transmission objective data to a first symbol, wherein the first symbol represents a combination of a second number of carrier waves that is selected from a first number of total carrier waves that are available for transmission; a first transformer configured to transform the first symbol into a transmission signal, wherein the transmission signal includes a first sample, wherein the first sample includes a third number of data, wherein the third number is greater than the first number, wherein the first sample is obtained by multiplying a first matrix by a second matrix to obtain a result, wherein the first matrix comprises the first symbol and has a size of the first number by 1 and the second matrix has a size of the first number by the third number, wherein the result multiplied by a diagonal matrix that includes coefficients is equivalent to multiplying a third matrix by a fourth matrix, wherein the third matrix comprises a non-singular matrix in a complex form having a size of the third number by the third number, and wherein the fourth matrix comprises an upper triangular matrix having a size of the third number by the first number; a multiplier configured to multiply the first sample included in the transmission signal by coefficients; and a transmitter configured to transmit the transmission signal to the receiving apparatus; wherein the receiving apparatus comprises: a receiver configured to receive the transmission signal, wherein the received transmission signal includes a different signal component from the transmission signal transmitted by the transmitting apparatus; a second transformer configured multiply a fifth matrix by a complex conjugate transpose of the third matrix to form a second sample, wherein the fifth matrix comprises the first sample and has a size of the first sample by 1; a first decoder configured to sequentially perform first decoding on the data included in the second sample; a second decoder configured to perform second decoding on the second sample such that a symbol acquired by the second decoding is a second symbol; and a demapper that decodes the transmission objective data from the second symbol acquired by the second decoder, wherein the first decoding is implemented by performing maximum likelihood decoding on the second sample and the second decoding is implemented by selecting a combination having a nearest value to the second sample value among combinations of the second sample corresponding to the second symbol.