Communication system and method using a relay node

A communication node that relays signals between a source node and a destination node, comprising:

• a first unitary matrix calculation unit configured to calculate a first unitary matrix based on a first channel between the source node and the relay node;
• a second unitary matrix calculation unit configured to calculate a second unitary matrix based on a second channel between the relay node and the destination node;
• a transformation matrix estimation unit configured to estimate a transformation matrix on the basis of a triangular matrix derived from QR decomposition of the first and/or the second channel matrix;
• a relaying signal generator configured to generates a relaying signal by multiplying a received signal by at least one of the first unitary matrix, the second unitary matrix, and the transformation matrix;
• and
• a transmission unit configured to transmit the relaying signal to the destination node.

A communication node that relays signals between a source node and a destination node, comprising:

• a first matrix calculation unit configured to calculate a unitary matrix based on one of a first channel matrix between the destination node and the relay node;
• a second matrix calculation unit configured to calculate a Moore-Penrose inverse matrix based on a second channel matrix between the source node and the relay node;
• a transformation matrix calculation unit configured to calculate a transformation matrix on the basis of a triangular matrix derived from QR decomposition of the second matrix;
• a relaying signal generator configured to generate a relaying signal by multiplying a received signal by the unitary matrix, Moore-Penrose inverse matrix, and the transformation matrix;
• and
• a transmission unit configured to transmit the relaying signal.

A communication node that relays signals between a source node and a destination node, comprising:

• a first matrix calculation unit configured to calculate a unitary matrix based on one of a first channel matrix between the source node and the relay node;
• a second matrix calculation unit configured to calculate a Moore-Penrose inverse matrix based on a second channel matrix between the destination node and the relay node;
• a transformation matrix calcualtion unit configured to calculate a transformation matrix based on a triangular matrix derived from QR decomposition of the second matrix;
• a relaying signal generator configured to generate a relaying signal by multiplying a received signal by the unitary matrix, Moore-Penrose inverse matrix, and the transformation matrix;
• and
• a transmission unit configured to transmit the relaying signal.

A communication method for relaying a transmission signal transmitted from a source node via a relay node to a destination node, comprising the steps of:

• performing a QR decomposition on a first channel matrix between the source node and the relay node and/or a second channel matrix between the relay node and the destination node;
• calculating one or more transformation matrices based on the QR decomposition of at least one of the first and second channel matrices;
• generating a relaying signal by multiplying a prescribed signal by at least one of the transformation matrices;
• transmitting the relaying signal from the relay node to the destination node;
• and
• receiving the relaying signal and detecting a desired signal from the received signal at the destination node.

A communication method for relaying a transmission signal transmitted from a source node via a relay node to a destination node, comprising the steps of:

• estimating a first unitary matrix based on a first channel matrix between the source node and the relay node;
• estimating a second unitary matrix based on a second channel matrix between the relay node and the destination node;
• estimating a transformation matrix based on a triangular matrix derived from QR decomposition of the first and/or second channel matrix;
• generating a relaying signal by multiplying a received signal by at least one of the first unitary matrix, the second unitary matrix, and the transformation matrix;
• transmitting the relaying signal from the relay node to the destination node;
• and
• receiving the relaying signal and detecting a desired signal from the received signal at the destination node.

A communication method for relaying a transmission signal transmitted from a source node via a relay node to a destination node, comprising the steps of:

• calculating a unitary matrix and a Moore-Penrose inverse matrix based on channel matrices of wireless transmission channels;
• calculating a transformation matrix on the basis of a triangular matrix derived from QR decomposition of at least one of the channel matrices;
• generating a relaying signal by multiplying a received signal by the unitary matrix, the Moore-Penrose inverse matrix, and the transformation matrix;
• transmitting the relaying signal from the relay node to the destination node;
• and
• receiving the relaying signal and detecting a desired signal from the received signal at the destination node.

A communication node for relaying a signal between a source node and a destination node, comprising:

• a relaying signal generator configured to generate a relaying signal based on a received signal;
• and
• a transmission unit configured to transmit the relaying signal to the destination node,
• wherein the relaying signal generator adaptively selects one of first through third signal generation modes,
• in the first mode, the signal generator calculates a first unitary matrix based on a first channel matrix between the source node and the relay node, a second unitary matrix based on a second channel matrix between the destination node and the relay node, and a transformation matrix based on the triangular matrix derived from QR decomposition of the first and/or the second matrix to generate the relaying signal by multiplying the received signal by at least one of the first unitary matrix, the second unitary matrix, and the transformation matrix;
• in the second mode, the signal generator calculates a Moore-Penrose inverse matrix based on the first channel matrix between the source node and the relay node, a unitary matrix based on the second channel matrix between the destination node and the relay node, and a transformation matrix based on the triangular matrix derived from QR decomposition of the first and/or the second channel matrix to generate the relaying signal by multiplying the unitary matrix, the Moore-Penrose inverse matrix and the transformation matrix;
• and
• in the third mode, the signal generator calculates a unitary matrix based on the first channel matrix between the source node and the relay node, a Moore-Penrose inverse matrix based on the second channel matrix between the destination node and the relay node, and a transformation matrix based on the triangular matrix derived from QR decomposition of the first and/or the second channel matrix to generate the relaying signal by multiplying the unitary matrix, the Moore-Penrose inverse matrix and the transformation matrix.