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) comprising:
determining an open loop uplink (UL) power control (PC) component based on pathloss measurement, wherein the open loop PC component comprises a cell-specific parameter and a WTRU-specific parameter, and wherein the cell-specific and WTRU-specific parameters are provided from higher layers;
determining a closed loop PC component including a correction factor, wherein the correction factor is based on a PC correction command signaled in a UL grant associated with a hybrid automatic repeat request (HARQ) process;
combining the open loop PC component and the closed loop PC component with a delta factor related to an offset value to determine a transmit power, wherein the offset value is related to a modulation and coding scheme (MCS); and
applying the transmit power in accordance with a timing of the HARQ process.
2. The method of claim 1 , further comprising receiving the PC correction command.
3. The method of claim 2 , wherein the PC correction command is received at a pre-configured signaling time.
4. The method of claim 1 , wherein the open loop PC component is based on a pathloss variation.
5. The method of claim 4 , wherein the pathloss variation is determined based on a variation between the pathloss prior to a discontinuous transmission and a time before resuming an UL transmission.
6. The method of claim 1 , wherein the PC correction command includes multiple command bits determined based on link quality.
7. A method for controlling transmit power of a wireless transmit receive unit (WTRU) comprising:
determining an open loop uplink (UL) power control (PC) component based on pathloss measurement;
determining a closed loop PC component including a correction factor, wherein the correction factor is based on a PC correction command including multiple command bits determined based on link quality;
combining the open loop PC component and the closed loop PC component with a delta factor related to an offset value to determine a transmit power, wherein the offset value is related to a modulation and coding scheme (MCS), and wherein the correction factor is determined using the following equation:
Δ closed =┌ESINR est −SINR target ┘;
where ESINR est and SINR target denotes the effective signal to interference noise ratio (ESINR) and target a SINR.
8. The method of claim 1 , wherein the transmit power is applied from the beginning of an uplink transmit time interval (TTI) until a transmit power update is received.
9. The method of claim 8 , wherein a value of the correction factor is zero (0) in an initial uplink transmission.
10. A method for controlling transmit power of a wireless transmit receive unit (WTRU) comprising:
determining an open loop uplink (UL) power control (PC) component based on pathloss measurement;
determining a closed loop PC component including a correction factor, wherein the correction factor is an uplink grant assignment;
combining the open loop PC component and the closed loop PC component with a delta factor related to an offset value to determine a transmit power, wherein the offset value is related to a modulation and coding scheme (MCS), and, wherein the grant based correction factor is determined using the following equation:
f ( UL grant assignment, SINT T )= SINR T −E{SINR est ( UL grant assignment)};
where SINR est (UL grant assignment) represents an eNodeB received SINR estimate which WTRU derives from the UL grant assignment.
11. The method of claim 10 , further comprising receiving a correction factor sign and determining whether to use the grant based correction factor based on the received correction factor sign.
12. The method of claim 10 , further comprising receiving an MCS mismatching indicator and determining whether to use the grant based correction factor based on the received MCS mismatching indicator.
13. The method of claim 10 , further comprising receiving an MCS mismatching indicator and determining whether to use an explicit correction command based on the received MCS mismatching indicator.
14. The method of claim 1 , further comprising determining an interference load indicator based on signaling received from a strongest neighboring cell.
15. The method of claim 14 , wherein the transmit power is based on a downlink reference signal wherein the interference load indicator is used to mitigate inter-cell interference.
16. A wireless transmit receive unit (WTRU) comprising a processor, wherein the processor is configured to:
determine an open loop uplink (UL) power control (PC) component based on pathloss measurement, wherein the open loop PC component comprises a cell-specific parameter and a WTRU-specific parameter, and wherein the cell-specific and WTRU-specific parameters are provided from higher layers;
determine a closed loop power control component including a correction factor, wherein the correction factor is based on a PC correction command signaled in a UL grant associated with a hybrid automatic repeat request (HARQ) process; and
combine the open loop PC component, the closed loop PC component and a delta factor related to an offset value to determine a WTRU transmit power, wherein the offset value is related to a modulation and coding scheme (MCS); and
apply the transmit power in accordance with a timing of the HARQ process.
17. The WTRU of claim 16 , further comprising a receiver, wherein the receiver is configured to receive the PC correction command.
18. The WTRU of claim 17 , wherein the PC correction command is received in a pre-configured signaling time.
19. The WTRU of claim 16 , wherein the open loop PC component is based on a pathloss variation.
20. The WTRU of claim 19 , wherein the pathloss variation is determined based on a variation between the pathloss prior to a discontinuous transmission (DTX) and a time before resuming an UL transmission.
21. The WTRU of claim 16 , wherein the PC correction command includes multiple command bits determined based on link quality.
22. A wireless transmit receive unit (WTRU) comprising a processor, wherein the processor is configured to:
determine an open loop uplink (UL) power control (PC) component based on pathloss measurement;
determine a closed loop power control component including a correction factor, wherein the correction factor is based on a PC correction command including multiple command bits determined based on link quality; and
combine the open loop PC component, the closed loop PC component and a delta factor related to an offset value to determine a WTRU transmit power, wherein the offset value is related to a modulation and coding scheme (MCS), and wherein the correction factor is determined using the following equation:
Δ closed =┌ESINR est −SINR target ┘;
where ESINR est and SINR target denote the effective signal to interference noise ratio (ESINR) and target a SINR.
23. The WTRU of claim 16 , further comprising a transmitter, wherein the transmitter is configured to apply the transmit power to the beginning of a next uplink transmit time interval (TTI) until a next transmit power update.
24. The WTRU of claim 23 , wherein a value of the correction factor is zero (0) in an initial uplink transmission.
25. A wireless transmit receive unit (WTRU) comprising a processor, wherein the processor is configured to:
determine an open loop uplink (UL) power control (PC) component based on pathloss measurement;
determine a closed loop power control component including a correction factor, wherein the correction factor is an uplink grant assignment; and
combine the open loop PC component, the closed loop PC component and a delta factor related to an offset value to determine a WTRU transmit power, wherein the offset value is related to a modulation and coding scheme (MCS), and wherein the grant based correction factor is determined using the following equation:
f ( UL grant assignment, SINT T )= SINR T −E{SINR est ( UL grant assignment)};
where SINR est (UL grant assignment) represents an eNodeB received SINR estimate which WTRU derives from the UL grant assignment.
26. The WTRU of claim 25 , wherein the processor is configured to determine whether to use the grant based correction factor based on a received correction factor sign.
27. The WTRU of claim 25 , wherein the processor is configured to determine whether to use the grant based correction factor based on a received MCS mismatching indicator.
28. The WTRU of claim 25 , wherein the processor is configured to determine whether to use an explicit correction command based on a received MCS mismatching indicator.
29. The WTRU of claim 16 , wherein the processor is configured to determine an interference load indicator based on signaling received from a strongest neighboring cell.
30. The WTRU of claim 29 , wherein the interference load indicator is used to mitigate inter-cell interference.