A method and an apparatus for supporting a voice service through a
radio channel in a mobile telecommunication
system are provided, wherein the method includes the steps of determining a voice codec mode,
byte-alignment information about a
byte-alignment scheme of a voice packet, a requested bandwidth and a codec type used for
processing a voice call in a procedure of establishing a call between a terminal and a
core network, forming a packet data protocol context establishing message including the codec type, the
byte-alignment information and the voice codec mode in order to establish a bearer for a packet call, and transmitting the formed packet data protocol context establishing message to the
core network from the terminal. The method further includes the steps of transmitting a radio bearer establishing message from an
access network to the terminal, the radio bearer establishing message including a radio link packet size set determined based on the codec type, the byte-alignment information and the voice codec mode, the
access network connecting the terminal with the
core network.