POWER CONTROLLING METHOD AND CORRESPONDING BASE STATION

• US 20100190521A1
• Filed: 07/23/2007
• Published: 07/29/2010
• Est. Priority Date: 07/23/2007
• Status: Active Grant

• Current Assignee: Alcatel-Lucent SA (Nokia Corporation)
• Original Assignee: Alcatel-Lucent SA (Nokia Corporation)
• Inventors: Wu, Keying
• Granted Patent: US 8,396,502 B2
• Time in Patent Office: Days
• US Class Current: 455/522
• CPC Class Codes: H04B 7/0452 Multi-user MIMO systems
• CPC Class Codes: H04W 52/146 Uplink power control
• CPC Class Codes: H04W 52/42 in systems with time, space, frequency or polarisation diversity

Abstract

A power controlling method and corresponding base station for controlling the transmission power of each user terminal are disclosed, in which, each user terminal is paired into virtual MIMO transmission. In the solution, first, determining the transmission power of each user terminal that makes the sum of the transmission power of each user terminal minimum under the case that the specific index for each user terminal meets a required threshold value; then, feed backing the determined transmission power of each user terminal to each user terminal. Compared with the prior art, the solution can achieve a preferable power efficiency.

Claims

1. A power controlling method for controlling the transmission power of each user terminal paired into virtual MIMO transmission, the method comprising the steps of:

determining the transmission power of each user terminal that makes the sum of the transmission power of each user terminal minimum under the case that a specific index for each user terminal meets a required threshold value; and

feedbacking the determined transmission power of each user terminal to each user terminal.

2. The method according to claim 1, wherein the specific index and the threshold value is bit error rate or error code rate.

3. The method according to claim 1, wherein the specific index is arrival signal-to-noise ratio (SNR) and the threshold value is signal-to-noise ratio.

4. The method according to claim 3, wherein the threshold value depends on the modulating and encoding mode used by each user terminal and the bit error rate or error code rate required for each user terminal.

5. The method according to claim 4, wherein the threshold value is obtained offline using the Monte Carlo simulation.

6. The method according to claim 1, wherein the step of determining the transmission power of each user terminal that makes the sum of the transmission power of each user terminal minimum comprises:

determining the arrival power of each user terminal that makes the sum of the arrival power of each user terminal minimum under the case that the specific index for each user terminal meets a required threshold value; and

determining the transmission power of each user terminal according to the above-determined arrival power of each user terminal and the path loss experienced by each user terminal.

7. The method according to claim 1, wherein successive interference cancellation (SIC) technique is employed to detect each user terminal, and user terminals with higher arrival SNRs can be detected first.

8. The method according to claim 7, wherein the threshold value is signal-to-noise ratio, and the specific index is the average output SNR of the detector at each level.

9. The method according to claim 7, wherein interference of signals from other user terminals is considered as an additive white Gaussian noise.

10. The method according to claim 7, wherein interference suppression technique is used to deal with the interference of the signals from other user terminals.

11. A base station for controlling the transmission power of each user terminal paired in virtual MIMO transmission, the base station comprising:

first determining means for determining the transmission power of each user terminal that makes the sum of the transmission power of each user terminal minimum under the case that a specific index for each user terminal meets a required threshold value; and

feedbacking means for feeding the above-determined transmission power of each user terminal back to each user terminal.

12. The base station according to claim 11, wherein the specific index and the threshold value is bit error rate or error code rate.

13. The base station according to claim 11, wherein the specific index is arrival signal-to-noise ratio (SNR) and the threshold value is signal-to-noise ratio.

14. The base station according to claim 13, wherein the threshold value depends on the modulating and encoding mode used by each user terminal and the bit error rate or error code rate required for each user terminal.

15. The base station according to claim 14, wherein the threshold value is obtained offline using the Monte Carlo simulation.

16. The base station according to claim 11, wherein the first determining means comprises:

second determining means for determining the arrival power of each user terminal that makes the sum of the arrival power of each user terminal minimum under the case that the specific index for each user terminal meets a required threshold value; and

third determining means for determining the transmission power of each user terminal according to the above-determined arrival power of each user terminal and path loss experienced by each user terminal.

17. The base station according to claim 11, wherein successive interference cancellation (SIC) technique is employed to detect each user terminal, and user terminals with higher arrival SNRs can be detected first.

18. The base station according to claim 17, wherein the threshold value is signal-to-noise ratio, and the specific index is an average output SNR of the detector at each level.

19. The base station according to claim 17, wherein interference of signals from other user terminals is considered as an additive white Gaussian noise.

20. The method according to claim 17, wherein interference suppression technique is used to deal with the interference of the signals from other user terminals.