Patent ID: 7852798

Claim:
A relay node for relaying a transmission signal, which is transmitted from a source node, to a destination node by using a multiple-input multiple-output (MIMO) system, the relay node comprising: receiving means for receiving the transmission signal from the source node; measuring means for measuring at least either transmission quality of a backward channel that is a transmission path between the source node and the relay node, or transmission quality of a forward channel that is a transmission path between the relay node and the destination node; selecting means for selecting a relay method as a conversion scheme for converting the transmission signal in the relay node, from among a plurality of relay methods in accordance with at least either the backward channel transmission quality or the forward channel transmission quality that is estimated by the measuring means; converting means for converting the transmission signal to a relay signal by multiplying the transmission signal by a conversion matrix corresponding to the relay method selected by the selecting means; and transmitting means for transmitting the relay signal obtained by conversion by the converting means to the destination node.