SPREADING A RESPONSE SIGNAL USING A FIRST SET OF ORTHOGONAL SEQUENCES AND A REFERENCE SIGNAL USING A SECOND SET OF SHORTER ORTHOGONAL SEQUENCES
A radio communication apparatus includes spreading circuitry that spreads a response signal using a first set of orthogonal sequences to produce a spread response signal. Each orthogonal sequence in the first set has a first length. The spreading circuitry also spreads a reference signal using a second set of orthogonal sequences to produce a spread reference signal. Each orthogonal sequence in the second set has a second length that is shorter than the first length. A radio transmitter transmits the spread response signal and the spread reference signal.
1 . A signal spreading method comprising:
spreading, using first spreading circuitry, a response signal using a first set of orthogonal sequences, to produce a spread response signal, each orthogonal sequence in the first set having a first length;
spreading, using the first spreading circuitry, a reference signal using a second set of orthogonal sequences, to produce a spread reference signal, each orthogonal sequence in the second set having a second length that is shorter than the first length;
transmitting, using a transmitter, the spread response signal and the spread reference signal.