APPARATUS AND METHOD FOR HYBRID AUTOMATIC REPEAT REQUESTING USING LOG LIKELIHOOD RATIO IN MOBILE COMMUNICATION SYSTEM

摘要

A method and an apparatus for a hybrid automatic repeat request using a log likelihood ratio in a mobile communication system are provided to improve an HARQ(Hybrid Automatic Repeat Request) signal detecting speed by reducing the number of repeated transmissions. An apparatus for a hybrid automatic repeat request using a log likelihood ratio in a mobile communication system includes a decoder(109), a CRC(Cyclic Redundancy Check) unit(111), and a repeat request unit. When a packet is received, the decoder decodes the packet according to a predetermined decoding scheme and outputs received bits to the CRC unit. The decoder calculates an LLR(Log Likelihood Ratio) bit of the received bits and outputs the result to the repeat request unit. When the packet is received, the CRC unit inspects an error from the received packet. When an error occurs in the received packet, the repeat request unit compares the calculated LLR value with an LLR threshold value, and determines a size of the packet to be retransmitted. The repeat request unit requests the retransmission of the packet of the determined size.