Combined open loop/closed loop method for controlling uplink power of a mobile station

• US 8,509,836 B2
• Filed: 03/07/2008
• Issued: 08/13/2013
• Est. Priority Date: 03/07/2007
• Status: Active Grant

• Current Assignee: Interdigital Technology Corporation (InterDigital, Inc.)
• Original Assignee: Interdigital Technology Corporation (InterDigital, Inc.)
• Inventors: Shin, Sung-Hyuk, Lin, Zinan, Grieco, Donald M., Olesen, Robert Lind
• Primary Examiner(s): Safaipour, Bobbak
• Application Number:
  US12/044,569
• Publication Number:
  US 20080220806A1
• Time in Patent Office: 1,985 Days
• Field of Search: 455/522, 370/318, 375/130, 375/259, 375/222, 375/295, 375/219, 375/220, 375/275
• US Class Current: 455/522
• CPC Class Codes: H04L 1/1812 Hybrid protocols; Hybrid automatic repeat request [HARQ]
• CPC Class Codes: H04W 52/06 TPC algorithms
• CPC Class Codes: H04W 52/08 Closed loop power control
• CPC Class Codes: H04W 52/10 Open loop power control
• CPC Class Codes: H04W 52/146 Uplink power control
• CPC Class Codes: H04W 52/242 taking into account path loss
• CPC Class Codes: H04W 76/28 Discontinuous transmission [DTX]; Discontinuous reception [DRX]

Abstract

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).

Claims

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.