Method of providing circuit switched (SC) service using high-speed downlink packet access (HSDPA) or high-speed uplink packet access (HSUPA)

A device of a wireless communication system that supports High Speed Packet Access (HSPA), the device comprising:

• a memory;
• and
• a processor configured to:
• receive at least one service data unit (SDU) from an upper layer;
• add a header, in a packet data convergence protocol (PDCP) layer, to the at least one received service data unit (SDU) to generate a protocol data unit (PDU),
• wherein the header includes timing information;
• and
• deliver the generated protocol data unit to a lower layer,
• wherein the timing information is used for a de-jittering queue on a receiver side,
• wherein the timing information is a value of a counter,
• wherein the value of the counter is set by a portion of a connection frame number (CFN) included in the header of the generated PDU,
• wherein the portion of the CFN is first to fifth List Significant Bits (LSBs) of the CFN, and
• wherein the data is circuit switched (CS) service data provided in a packet switched (PS) network.