Uplink power alignment estimation in a communication system

• US 8,068,868 B2
• Filed: 12/28/2009
• Issued: 11/29/2011
• Est. Priority Date: 12/28/2009
• Status: Active Grant

• Current Assignee: Google Technology Holdings LLC (Alphabet Inc.)
• Original Assignee: Motorola Mobility, Inc. (Lenovo Group Ltd.)
• Inventors: Chen, Jiangnan Jason, Shihab, Jamil M.
• Primary Examiner(s): GESESSE, TILAHUN
• Application Number:
  US12/647,570
• Publication Number:
  US 20110159911A1
• Time in Patent Office: 701 Days
• Field of Search: 455/522, 455/69, 455/127.1
• US Class Current: 455/522
• CPC Class Codes: H04W 52/146 Uplink power control
• CPC Class Codes: H04W 52/221 using past power control commands
• CPC Class Codes: H04W 52/367 Power values between minimum and maximum limits, e.g. dynamic range
• CPC Class Codes: H04W 52/545 modifying TPC bits in special situations

Abstract

A method and apparatus for uplink power alignment estimation in a communication system includes a step 600 of defining an upper threshold and a lower threshold for a transmit power correction (TPC) level. A next step 602 includes keeping a total of accumulated TPC commands. A next step 604 includes determining that a power correction is needed. A next step 608 includes generating a TPC command to be sent to a user equipment per the needed power correction. A next step 610 includes adjusting the total according to one of the following conditions: if the total is between the upper and lower thresholds then the total is changed per the needed power correction, if the total is at either of the thresholds and the needed power correction would not exceed either of the thresholds then the total is changed per the needed power correction, and if the total is at either of the thresholds and the needed power correction would exceed either of the thresholds then total is kept the same.

Claims

1. A method for uplink power alignment estimation by an evolved Node B (eNB) in a communication system, the method comprising the steps of:

defining an upper threshold and a lower threshold for a transmit power correction (TPC) level;

keeping a total of accumulated TPC commands sent to a user equipment (UE);

determining that a power correction is needed;

generating a TPC command to be sent to the UE per the needed power correction;

adjusting the total according to one of the following conditions;

if the total is between the upper and lower thresholds then the total is changed per the needed power correction,

if the total is at either of the thresholds and the needed power correction would not exceed either of the thresholds then the total is changed per the needed power correction, and

if the total is at either of the thresholds and the needed power correction would exceed either of the thresholds then total is kept the same;

sending the TPC command to the UE.

2. The method of claim 1, further comprising the step of measuring a received signal energy from a user equipment.

3. The method of claim 2, wherein the defining step includes defining a second upper threshold and second lower threshold for the received signal energy.

4. The method of claim 3, wherein the generating step includes setting the TPC command to zero if the received signal energy falls outside of the second upper threshold and second lower threshold and the TPC command will not bring the received signal energy within the second upper threshold or second lower threshold.

5. The method of claim 4, wherein the generating step includes setting the TPC command to 0 dB if the received signal energy exceeds the second upper threshold and TPC command calls for an incremental power correction.

6. The method of claim 4, wherein the generating step includes setting the TPC command to 0 dB if the received signal energy falls below the second lower threshold and TPC command calls for a decremental power correction.

7. The method of claim 1, wherein the adjusting step includes adjusting the total according to one of the following conditions:

if the total is between the upper and lower thresholds then the total is changed by adding the TPC,

if the total is at the upper threshold and adding the TPC would not go over the upper threshold then the total is changed by adding the TPC,

if the total is at the lower threshold and adding the TPC would not go under the lower threshold then the total is changed by adding the TPC,

if the total is at the upper threshold and adding the TPC would go over the upper threshold then the total is not changed, and

if the total is at the lower threshold and adding the TPC would go under the lower threshold then the total is not changed.

8. The method of claim 1, wherein the adjusting step includes adjusting the total according to one of the following conditions:

if the total is between the upper and lower thresholds then the total is changed by adding the TPC,

if the total is at the upper threshold and the sign of the TPC is not the same as the sign of a last TPC then the total is changed by adding the TPC,

if the total is at the lower threshold and the sign of the TPC is not the same as the sign of the last TPC then the total is changed by adding the TPC,

if the total is at the upper threshold and the sign of the TPC is the same as the sign of the last TPC then the total is not changed, and

if the total is at the lower threshold and the sign of the TPC is the same as the sign of the last TPC then the total is not changed.

9. The method of claim 1, wherein the determining step includes determining that CRCaccumulated is greater than Tcrc, where CRCaccumulated is a number of accumulated errors received from the UE over a predetermined time period and Tcrc is a threshold for a number of acceptable errors received from the UE.

10. The method of claim 1, further comprising the step of realigning the power control state at the UE and eNB in response to a power headroom report.

11. An evolved NodeB (eNB) for providing uplink power alignment estimation in a communication system, the eNB comprising:

a memory operable to hold a defined upper threshold and a lower threshold for a transmit power correction (TPC) level, and to keep a total of accumulated TPC commands sent to a user equipment (UE);

a processor coupled to the memory, the processor operable to determining that a power correction is needed, generate a TPC command to be sent to the UE per the needed power correction, and adjust the total according to one of the following conditions;

if the total is between the upper and lower thresholds then the total is changed per the needed power correction, if the total is at either of the thresholds and the needed power correction would not exceed either of the thresholds then the total is changed per the needed power correction, and if the total is at either of the thresholds and the needed power correction would exceed either of the thresholds then total is kept the same; and

a transceiver coupled to the processor and operable to send the TPC command to the UE.

12. The eNB of claim 11, wherein the transceiver is further operable to measure a received signal energy from a user equipment.

13. The eNB of claim 12, wherein the memory is further operable to store a defined second upper threshold and a second lower threshold for the received signal energy.

14. The eNB of claim 13, wherein the processor is further operable to set the TPC command to zero if the received signal energy falls outside of the second upper threshold and second lower threshold and the TPC command will not bring the received signal energy within the second upper threshold or second lower threshold.