Apparatus and method for transmitting and receiving uplink power offset information in a mobile communication system supporting HSDPA
A radio network controller (RNC) transmits 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 the 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. The Node B transmits data to the UE over a high-speed downlink shared channel (HS-DSCH) and the UE transmits information indicating reception of the data to the Node B over the uplink HS-DPCCH. The RNC informs the UE 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 RNC informs the Node B of the power offset so that the Node B can determine a threshold value for determining information indicating reception of the data, depending on the power offset.
1. A method for transmitting by a radio network controller (RNC) 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 the 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:
informing the UE of a power offset;
determining a transmission power increment of the uplink HS-DPCCH, if it is determined that the UE is located in the handover region;
informing the Node B of the power offset; and
determining by the Node B a threshold value for determining the response information received from the UE, depending on the power offset.
2. The method of claim 1 , wherein the power offset is transmitted to the UE through a medium access control (MAC) message.
3. The method of claim 2 , wherein the MAC message serves as an active set update message.
4. The method of claim 1 , wherein the power offset is transmitted to the Node B through a Node B application part (NBAP) message.
5. The method of claim 4 , wherein the NBAP message serves as a radio link reconfiguration request message.
6. The method of claim 1 , wherein the power offset is transmitted to the Node B, using a frame protocol.
7. The method of claim 6 , wherein when using the frame protocol, the RNC transmits the power offset to the Node B through a spare field of a control frame.
8. The method of claim 6 , wherein when using the frame protocol, the RNC inserts the power offset into spare bits in a header field of a data frame and transmits the power offset-inserted data frame to the Node B.
9. The method of claim 1 , wherein the response information is defined as one of an acknowledgement (ACK) and a negative acknowledgement (NACK), and provides different power offsets for the ACK and the NACK.
10. The method of claim 9 , wherein a transmission power increment based on the power offset is the response information, and a transmission power increment when the response information received from UE is defined as the NACK is greater than a transmission power increment when the response information is defined as the ACK.
11. The method of claim 1 , wherein the uplink HS-DPCCH transmits channel quality indicator (CQI) information for a channel transmitted from the Node B to the UE and the response information, and provides different power offsets for the response information and the CQI information.
12. The method of claim 11 , wherein a transmission power increment for the CQI information based on the power offset is greater than a transmission power increment for the response information.
13. 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.
14. The apparatus of claim 13 , wherein the power offset is transmitted to the UE through a medium access control (MAC) message.
15. The apparatus of claim 14 , wherein the MAC message serves as an active set update message.
16. The apparatus of claim 13 , wherein the power offset is transmitted to the Node B through a Node B application part (NBAP) message.
17. The apparatus of claim 16 , wherein the NBAP message serves as a radio link reconfiguration request message.
18. The apparatus of claim 13 , wherein the power offset is transmitted to the Node B, using a frame protocol.
19. The apparatus of claim 18 , wherein when using the frame protocol, the RNC transmits the power offset to the Node B through a spare field of a control frame.
20. The apparatus of claim 18 , wherein when using the frame protocol, the RNC inserts the power offset into spare bits in a header field of a data frame and transmits the power offset-inserted data frame to the Node B.
21. The apparatus of claim 13 , wherein the response information is defined as one of an acknowledgement (ACK) and a negative acknowledgement (NACK), and provides different power offsets for the ACK and the NACK.
22. The apparatus of claim 21 , wherein a transmission power increment based on the power offset is the response information, and a transmission power increment when the response information is defined as the NACK is greater than a transmission power increment when the response information is defined as the ACK.
23. The apparatus of claim 13 , wherein the uplink HS-DPCCH transmits channel quality indicator (CQI) information for a channel transmitted from the Node B to the UE and the response information, and provides different power offsets for the response information and the CQI information.
24. The apparatus of claim 23 , wherein a transmission power increment for the CQI information based on the power offset is greater than a transmission power increment for the response information.
25. 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.
26. The method of claim 25 , wherein the response information is defined as one of an acknowledgement (ACK) and a negative acknowledgement (NACK), and provides different power offsets for the ACK and the NACK.
27. The method of claim 26 , wherein a transmission power increment based on the power offset is the response information, and a transmission power increment when the response information is defined as the NACK is greater than a transmission power increment when the response information is defined as the ACK.
28. The method of claim 25 , wherein the uplink HS-DPCCH transmits channel quality indicator (CQI) information for a channel transmitted from the Node B to the UE and the response information, and provides different power offsets for the information and the CQI information.
29. The apparatus of claim 28 , wherein a transmission power increment for the CQI information based on the power offset is greater than a transmission power increment for the response information.