Qr decomposition apparatus and method for mimo system

A QR decomposition method for a Multiple Input Multiple Output (MIMO) system, comprising:

• calculating a vector size norm for a channel input;
• calculating a column value of a unitary matrix Q using a delayed channel input and √{square root over (norm)};
• calculating a row value of an upper triangular matrix R using the delayed channel input, the calculated column value of the unitary matrix Q, and 1/√{square root over (norm)};
• calculating a Q update matrix value using the delayed channel input, the calculated row value of the upper triangular matrix R, and a delayed column value of the unitary matrix Q;
• and
• calculating a norm update matrix value using a delayed norm value and the calculated row value of the triangular matrix value.

A calculator for a QR decomposition apparatus in a Multiple Input Multiple Output (MIMO) system comprising:

• a plurality of fixed to floating point number converting means for converting a fixed point number type input to a floating point number type;
• a calculating means for performing a predetermined operation using only a significant value outputted from each of the plurality of fixed to floating point number converting means;
• an adding means for adding exponent values outputted from the plurality of fixed to floating point number converting means;
• and
• a floating to fixed point number converting means for converting a floating point number type to a fixed point number type using the result of the predetermined operation and the added exponent value.