Combined open loop/closed loop method for controlling uplink power of a mobile station
A method and apparatus are disclosed comprising a combined open loop/closed loop uplink power control scheme for E-UTRA. The combined open and closed loop method for UL intra-cell PC controls the wireless transmit receive unit (WTRU) transmit power spectral density (PSD), PSD Tx , (e.g. power per RB).
1. A method for controlling transmit power of a wireless transmit/receive unit (WTRU), the method comprising:
receiving signaling indicating an uplink (UL) resource assignment, a power control (PC) correction command, an assigned modulation coding set (MCS) and a cell-specific pathloss compensation factor;
determining a filtered pathloss estimate;
determining a pathloss compensation component as a function of the filtered pathloss estimate and the cell specific pathloss compensation factor;
determining a transmit power based on a combination of a power component corresponding to a bandwidth of the UL resource assignment, an open loop PC component, a closed loop PC component and a power offset, wherein the open loop PC component comprises the pathloss compensation component and a cell specific open loop PC nominal component, wherein the closed loop PC component comprises a correction factor, wherein the correction factor is based on the PC correction command, and wherein the power offset is related to the assigned MCS; and
applying the transmit power.
2. The method of claim 1 , wherein applying the transmit power comprises:
applying the transmit power in accordance with a timing of a Hybrid Access Repeat Request (HARQ) process.
3. The method of claim 1 , wherein applying the transmit power comprises:
applying the transmit power at a next transmission time of a Hybrid Access Repeat Request (HARQ) process following reception of an UL grant.
4. The method of claim 1 , wherein applying the transmit power comprises applying the transmit power to any of data and control signaling.
5. The method of claim 1 , wherein the open loop PC component comprises a WTRU-specific parameter.
6. The method of claim 1 , wherein the correction factor is zero (0) in an initial uplink transmission.
7. The method claim 1 , wherein applying the transmit power comprises:
applying a maximum transmit power level instead of the transmit power on condition that the transmit power is greater than or equal to the maximum transmit power level.
8. The method of claim 7 , wherein the maximum power transmit level is based on any of a maximum allowed power and a power class of the WTRU.
9. The method of claim 7 , further comprising: receiving signaling indicating a maximum power transmit level.
10. The method of claim 1 , wherein determining a filtered pathloss estimate comprises: determining the filtered pathloss estimate as a function of a filter coefficient, an instantaneous pathloss and any of a prior pathloss estimate and a prior filtered pathloss estimate.
11. A wireless transmit/receive unit (WTRU) comprising a processor, wherein the processor is configured to:
receive signaling indicating an uplink (UL) resource assignment, a power control (PC) correction command, an assigned modulation coding set (MCS) and a cell-specific pathloss compensation factor;
determine a filtered pathloss estimate;
determine a pathloss compensation component as a function of the filtered pathloss estimate and the cell specific pathloss compensation factor;
determine a transmit power based on a combination of a power component corresponding to a bandwidth of the UL resource assignment, an open loop PC component, a closed loop PC component and a power offset, wherein the open loop PC component comprises the pathloss compensation component and a cell specific open loop PC nominal component, wherein the closed loop PC component comprises a correction factor, wherein the correction factor is based on the PC correction command, and wherein the power offset value is related to the assigned MCS; and
apply the transmit power.
12. The WTRU of claim 11 , wherein the processor is adapted to apply the determined transmit power in accordance with a timing of a hybrid automatic repeat request (HARQ) process.
13. The WTRU of claim 11 , wherein the processor is configured to:
apply the transmit power at a next transmission time of a Hybrid Access Repeat Request (HARQ) process following reception of an UL grant.
14. The WTRU of claim 11 , wherein the processor is configured to apply the transmit power to any of data and control signaling.
15. The WTRU of claim 11 , wherein the open loop PC component comprises a WTRU-specific parameter.
16. The WTRU of claim 11 , wherein the correction factor is zero (0) in an initial uplink transmission.
17. The WTRU claim 11 , wherein the processor is configured to:
applying a maximum transmit power level instead of the transmit power on condition that the transmit power is greater than or equal to the maximum transmit power level.
18. The WTRU of claim 17 , wherein the maximum power transmit level is based on any of a maximum allowed power and a power class of the WTRU.
19. The WTRU of claim 17 , wherein the processor is configured to: receive signaling indicating a maximum power transmit level.
20. The WTRU of claim 11 , wherein the processor is configured to determine the filtered pathloss estimate as a function of a filter coefficient, an instantaneous pathloss and any of a prior pathloss estimate and a prior filtered pathloss estimate.