Patent ID: 7672408

Claim:
A signal separation device that receives a plurality of signals transmitted from a plurality of transmission devices and separates the received signals into the individual transmission signals, said signal separation device comprising: a signal point derivation unit configured to multiply the received signals with respective elements of a unitary matrix, and derive at least one received-signal signal point on a signal point distribution diagram, different signals being related to different signal points at different positions on said signal point distribution diagram, said received-signal signal point being a signal point corresponding to one of the received signals; a definition unit configured to define a plurality of sections on the signal point distribution diagram, each of the sections including a first predetermined number of the signal points, the definition unit being further configured to define a plurality of sub-sections in a received-signal section, each of the sub-sections including a second predetermined number of signal points, the received-signal section being a quadrant of the signal point distribution diagram; a detection unit configured to detect the received-signal section from said sections, said received-signal section including the received-signal signal point, the detection unit being further configured to detect a received-signal sub-section from the plurality of sub-sections on the received-signal section, the received-signal sub-section including the received-signal signal point and being a quadrant of the signal point distribution diagram having an origin at the received-signal section; a selection unit configured to select the signal points in the received-signal section as candidates of the received-signal signal point, the selection unit being further configured to select at least the signal points included in the received-signal sub-section as candidates of the received-signal signal point; and a determination unit configured to determine the transmission signals based on the selected signal points, wherein the origin of the signal point distribution diagram is set at one of the signal points, the quadrant corresponding to the received-signal section is detected, the origin of the signal point distribution diagram is moved into the quadrant corresponding to the received-signal section, and the quadrant corresponding to the received-signal sub-section is detected.