TRANSMITTING/RECEIVING APPARATUS FOR PACKET RE-TRANSMISSION IN MOBILE COMMUNICATION SYSTEM AND METHOD THEREFOR

摘要

PURPOSE: A transmitting/receiving apparatus for packet re-transmission in a mobile communication system and a method therefor are provided to make an LLR(Log Likelihood Ratio) of a turbo decoder input bit combined at a receiver uniform and obtain excellent decoding efficiency by re-arranging bits mapped with one modulation symbol and mapping and transmitting them with a reliability bit different from the previous transmission. CONSTITUTION: A CRC(Cyclic Redundancy Check) adder(402) inputs information bits for transmission and adds a CRC bit for checking an error by the unit of packet data to the inputted information bit. A channel coder(404) receives the CRC-bit added packet data, codes them by using a certain coding technique and outputs coded bits. A rate matching unit(406) performs a rate matching on the coded bits received from the channel coder(404) through operations such as repetition or puncturing. Symbols which have passed through the rate matching unit(406) pass an interleaver(408) and randomly re-arranged. A bit re-arranging unit(410) determines whether to perform a bit-re-arrangement according to whether a receiver has requested re-transmission. A modulator(414) maps the coded bits which have passed the bit re-arranging unit(410) with certain symbols according to a predetermined modulation method and outputs them. A controller(420) controls the general operation of each element of a transmitter. The controller(420) determines a coding rate and a modulation method according to a current radio channel state, controls a coding rate of the channel coder(404) according to a determined coding rate and controls the modulator(414) according to the determined modulation method. The controller(420) processes a re-transmission request from an upper layer which has received the re-transmission request from the receiver and provides corresponding information to a re-arranging controller(412).