RETRANSMISSION DEVICE USING FREQUENCY DIVERSITY IN ORTHOGONAL FREQUENCY DIVISION MULTIPLEXING MOBILE COMMUNICATION SYSTEM AND METHOD THEREOF

摘要

PURPOSE: A retransmission device using a frequency diversity in an OFDM(Orthogonal Frequency Division Multiplexing) mobile communication system is provided to retransmit data with a replica by using cyclic rotation in the OFDM mobile communication system, thereby increasing data retransmission efficiency by obtaining a frequency diversity effect with the retransmitted data. CONSTITUTION: A physical layer ARQ controller(211) determines whether to retransmit data according to a general ARQ method or by using a replica, if the data has to be retransmitted. The physical layer ARQ controller(211) transmits a determined method to a controller(215). The controller(215) controls switching operations of the first switch(217) and the second switch(223) according to the determined retransmission method. A "0" generator(213) is switched on under control of the controller(215), and generates "0" during a symbol period by a QAM/QPSK mapping in order to prevent transmission delay. A buffer(219) buffers a switching-on signal of the first switch(217). A replica generator(221) inputs symbols buffered by the buffer(219) with one OFDM symbol unit, and outputs a replica to the second switch(223).