High speed shared radio channel transmit power control

• US 20070060187A1
• Filed: 09/09/2005
• Published: 03/15/2007
• Est. Priority Date: 09/09/2005
• Status: Active Grant

• Current Assignee: Telefonaktiebolaget LM Ericsson
• Original Assignee: Telefonaktiebolaget LM Ericsson
• Inventors: Wiberg, Niclas, Olsson, Jonas, Englund, Eva
• Granted Patent: US 7,756,543 B2
• Time in Patent Office: Days
• US Class Current: 455/522
• CPC Class Codes: H04W 52/143 Downlink power control
• CPC Class Codes: H04W 52/16 Deriving transmission power values from another channel
• CPC Class Codes: H04W 52/221 using past power control commands
• CPC Class Codes: H04W 52/241 taking into account channel quality metrics, e.g. SIR, SNR, CIR, Eb/lo
• CPC Class Codes: H04W 52/286 during data packet transmission, e.g. high speed packet access [HSPA]
• CPC Class Codes: H04W 52/322 Power control of broadcast channels
• CPC Class Codes: H04W 52/325 Power control of control or pilot channels

Abstract

To increase throughput efficiency and attain a higher achieved bit rate for data transmissions over a high speed shared channel, a variable transmit power increase factor is used to control the maximum rate at which the power at which data is transmitted over the high speed shared channel can increase. In one non-limiting implementation, the power increase factor F is varied with the current total downlink transmitted power available for high speed downlink transmission. For example, when the available high speed shared channel power is large, the variable transmit power increase factor assumes a more conservative value, e.g., a smaller F value, at the beginning of the high speed downlink transmission, and then a more liberal value, e.g., a larger F value, later during the high speed downlink transmission.

Claims

1. A method for regulating the transmit power level of a data transmission over a high speed shared radio channel in a cell in a radio communications system, comprising:

determining an available amount power for the high speed radio transmission;

determining a variable power increase that controls a rate at which the transmit power level for a high speed data transmission over the high speed shared radio channel can increase;

setting the power level of the high speed data transmission based on the determined variable power increase; and

transmitting data over the high speed data transmissions channel based on the set power level.

2. The method in claim 1, wherein the variable power increase is lower at the beginning of the data transmission over the high speed shared radio channel, and later in the data transmission over the high speed shared radio channel, the variable power increase is greater.

3. The method in claim 1, further comprising:

measuring a power level of transmissions over non-high speed radio channels in the cell,

wherein the available amount power for the high speed data transmission is determined using the measured power level.

4. The method in claim 1, wherein setting the power level of the high speed data transmission includes selecting a transport format for the high speed data transmission.

5. The method in claim 1, wherein the power level of the high speed data transmission is determined in accordance with the following:

P _HS =P _tx *F−

P _non-HS

where P_HS is the power available for the high speed data transmission channels in the cell, P_tx is the total transmit power in the last subframe in the cell, and P_non-HS is the power used for non-high speed data communications in the cell, and F is a power increase factor.

6. The method in claim 5, wherein the power increase factor F is determined in accordance with the following:

$F<br><br>\left(\mathrm{\beta <br><br>}\right)=1+\left(\mathrm{\beta <br><br>}-1\right)·<br><br>{\left(\frac{P_{\mathrm{tx}}}{P_{\max }}\right)}^{\mathrm{\beta <br><br>}}$

where β

≧

1 and P_max is the maximum total power level permitted in the cell.

7. The method in claim 6, wherein β

is selected by an operator or system vendor.

8. Apparatus for regulating the transmit power level of a data transmission over a high speed shared radio channel in a radio communications system, comprising:

means for determining an available amount power for the high speed radio transmission;

means for determining a variable power increase that controls a rate at which the transmit power level for a high speed data transmission over the high speed shared radio channel can increase;

means for setting the power level of the high speed data transmission based on the determined variable power increase; and

means for transmitting data over the high speed data transmissions channel based on the set power level.

9. The apparatus in claim 8, wherein means for setting is configured such that the variable power increase is lower at the beginning of the data transmission over the high speed shared radio channel, and later in the data transmission over the high speed shared radio channel, the variable power increase is greater.

10. The apparatus in claim 8, further comprising:

means for measuring a power level of transmissions over non-high speed radio channels,

wherein the means for determining is configured to determine the available amount power for the high speed data transmission using the measured power level.

11. The apparatus in claim 8, wherein the means for setting is configured to select a transport format for the high speed data transmission.

12. The apparatus in claim 8, wherein the means for setting is configured to determine the power level of the high speed data transmission in accordance with the following:

P _HS =P _tx *F−

P _non-HS

where P_HS is the power available for the high speed data transmission channels, P_tx is the total transmit power in the last subframe in the cell, and P_non-HS is the power used for non-high speed data communications in the cell, and F is a power increase factor.

13. The apparatus in claim 12, wherein means for determining the power increase factor F is configured to determine the power increase factor F in accordance with the following:

$F<br><br>\left(\mathrm{\beta <br><br>}\right)=1+\left(\mathrm{\beta <br><br>}-1\right)·<br><br>{\left(\frac{P_{\mathrm{tx}}}{P_{\max }}\right)}^{\mathrm{\beta <br><br>}}$

where β

≧

1 and P_max is a maximum total transmission power level permitted in the cell.

14. A base station for regulating the transmit power level of a data transmission to a wireless user equipment over a high speed downlink shared radio channel in a radio communications system, comprising:

radio transmitting circuitry for transmitting data over the high speed downlink shared radio channel;

electronic control circuitry configured to;

determine an available amount power for the high speed radio transmission;

determine a variable power increase that controls a rate at which the transmit power level for a high speed data transmission over the high speed shared radio channel can increase; and

set the power level of the high speed data transmission based on the determined variable power increase; and

a transmission scheduler, coupled to the radio transmitting circuitry and electronic control circuitry, for controlling transmission data over the high speed data transmissions channel based on the set power level.

15. The apparatus in claim 14, wherein the electronic control circuitry is configured to determine a variable power increase factor such that the variable power increase is lower at the beginning of the data transmission over the high speed shared radio channel, and later in the data transmission over the high speed shared radio channel, the variable power increase is greater.

16. The apparatus in claim 14, further comprising:

power measurement circuitry for measuring a power level of transmissions over non-high speed radio channels,

wherein the electronic control circuitry is configured to determine the available amount power for the high speed data transmission using the measured power level.

17. The apparatus in claim 14, wherein the electronic control circuitry is configured to select a transport format for the high speed data transmission.

18. The apparatus in claim 14, wherein the electronic control circuitry is configured to determine the power level of the high speed data transmission in accordance with the following:

P _HS =P _tx *F−

P _non-HS

where P_HS is the power available for the high speed data transmission channels, P_tx is the total transmit power in the last subframe in the cell, and P_non-HS is the power used for non-high speed data communications in the cell, and F is a power increase factor.

19. The apparatus in claim 18, wherein the electronic control circuitry is configured to determine the power increase factor F in accordance with the following:

$F<br><br>\left(\mathrm{\beta <br><br>}\right)=1+\left(\mathrm{\beta <br><br>}-1\right)·<br><br>{\left(\frac{P_{\mathrm{tx}}}{P_{\max }}\right)}^{\mathrm{\beta <br><br>}}$

where β

≧

1 and P_max is a maximum total transmission power level permitted in the cell.

20. The apparatus in claim 14, wherein β

is selected by an operator or system vendor.