Apparatus and method for communication

Abstract

An eigen value expansion sectioncalculates eigen values and eigen vectors in a correlation matrix or covariance matrix of input signals. When the ratio between a maximum eigen value and other eigen values is equal to or lower than a threshold, an assignment method selection sectionselects a code assignment method whereby systematic bits are transmitted with their respective eigen vectors. As a result, a communication apparatustransmits a systematic bit X with the respective eigen vectors. On the other hand, when the ratio between a maximum eigen value and other eigen values is greater than the threshold, the assignment method selection sectionselects a code assignment method whereby systematic bits are transmitted with only the eigen vector having the maximum eigen value. As a result, the communication apparatustransmits the systematic bit X with only the eigen vector having the maximum eigen value. This makes it possible to obtain an effect of improving sufficient communication quality even when the difference between the maximum eigen value and other eigen values is large in a communication system which combines a turbo code and MIMO.