Apparatus and method for transmitting and receiving uplink power offset information in a mobile communication system supporting HSDPA

An apparatus for transmitting and receiving a power offset for controlling transmission power of an uplink high-speed dedicated physical control channel (HS-DPCCH) when a user equipment (UE) enters a handover region, in a mobile communication system including a radio network controller (RNC), a Node B connected to the RNC, and the UE located in one of at least two cell areas occupied by the Node B, wherein the Node B transmits data to the UE over a high-speed downlink shared channel (HS-DSCH) and the UE transmits response information indicating reception status of the data to the Node B over the uplink HS-DPCCH, the apparatus comprising:

• the RNC for informing the UE and the Node B of a power offset for determining a transmission power increment of the uplink HS-DPCCH, if it is determined that the UE is located in the handover region;
• the UE for increasing transmission power of the uplink HS-DPCCH depending on the power offset, and transmitting the uplink HS-DPCCH at the increase transmission power;
• and
• the Node B for determining a threshold value depending on the transmission power of the uplink HS-DPCCH, estimated based on the power offset, and determining response information received from the UE depending on the threshold value.

A method for controlling transmission power of an uplink high-speed dedicated physical control channel (HS-DPCCH) when a user equipment (UE) enters a handover region, in a mobile communication system including a radio network controller (RNC), a Node B connected to the RNC, and the UE located in one of at least two cell areas occupied by the Node B, wherein the Node B transmits data to the UE over a high-speed downlink shared channel (HS-DSCH) and the UE transmits a response information indicating reception status of the data to the Node B over the uplink HS-DPCCH, the method comprising the steps of:

• transmitting to the RNC a report indicating that the UE enters the handover region;
• receiving a power offset from the RNC through an active set update message in response to the report;
• increasing transmission power of the uplink HS-DPCCH depending on the power offset;
• and
• transmitting the uplink HS-DPCCH at the increased transmission power.