| 摘要 |
<p>A base station apparatus (A) allocates two orthogonal resources to be used for transmitting an ACK/NACK signal to a mobile station apparatus (B) (401). The base station apparatus (A) then transmits resource allocation information related to a downlink signal to the mobile station apparatus (B) (402). The base station apparatus (A) transmits a downlink data signal to the mobile station apparatus (B) (403). The mobile station apparatus (B), when having received the resource allocation information related to the downlink signal (402) and the downlink data signal (403), performs a demodulation process including error corrections, error detections and so on for the received information and signal (404). The results from performing the error corrections, error detections and so on (404) are used to generate an ACK/NACK signal (405). The ACK/NACK signal is modulated and spread using the modulation scheme information and orthogonal resources (spread codes) notified in step 401 (406). The ACK/NACK signal in accordance with the time and frequency resources allocated in step 401 is mapped onto each of the two types of spread sequences (406) (407). In a case of OFDMA, the frequency domain signal may be subjected to an IFFT process and a guard interval may be added to the frequency domain signal. The signal mapped in accordance with the time and frequency resources (407) is then mapped to antennas corresponding to the respective allocated spread codes (401) (408). In step 408, in a case of including reference signals, the reference signals are mapped to the corresponding respective antennas at the same time. The mobile station apparatus (B) transmits, based on the resource allocations of the base station apparatus (A), the ACK/NACK signals to the base station apparatus (A) (409). The base station apparatus (A) performs a process in accordance with the transmission schemes of the ACK/NACK signals and then extracts the ACK/NACK signals in accordance with the time and frequency resources allocated in step 401 (410). Then, the base station apparatus (A) estimates transmission paths based on the reference signals included in the ACK/NACK signals in step 408, compensates the received ACK/NACK signals and thereafter despreads the ACK/NACK signals in accordance with the two types of orthogonal resources allocated in step 401 (411). Further, the base station apparatus (A) performs a demodulation process to reproduce the bits combined and transmitted at the same time (412). In this way, a transmission diversity method is provided wherein when a transmission diversity is applied, no interferences occur between the codes in a CDMA environment of code spread in the time and frequency directions.</p> |
