Power control in a radio data communication system adapted using transmission load

• US 6,912,228 B1
• Filed: 04/14/2000
• Issued: 06/28/2005
• Est. Priority Date: 04/14/2000
• Status: Expired due to Term

• Current Assignee: Unwired Planet LLC (JP Morgan Chase & Co)
• Original Assignee: Telefonaktiebolaget LM Ericsson
• Inventors: Dahlman, Erik, Parkvall, Stefan
• Primary Examiner(s): Phan, Man U.
• Assistant Examiner(s): Nguyen, Toan
• Application Number:
  US09/550,059
• Time in Patent Office: 1,901 Days
• Field of Search: 370/231, 370/232, 370/234, 370/235, 370/318, 370/320, 370/332, 370/335, 370/428, 455/13.4, 455522-526
• US Class Current: 370/441
• CPC Class Codes: H04W 52/223 predicting future states of the transmission
• CPC Class Codes: H04W 52/226 using past references to control power, e.g. look-up-table
• CPC Class Codes: H04W 52/343 taking into account loading or congestion level

Abstract

The present invention employs a power control methodology that adapts to the transmission load associated with communications between a base station and a mobile terminal. In one example embodiment, the base station gradually adjusts the power data transmitted to the mobile terminal based on that associated transmission load. As a result, radio channel quality measurements influenced by that base station data transmission to the mobile terminal are not significantly affected by the transmit power adjustment. In other words, the rate at which the transmit power is changed is slower than the rate at which mobile stations measure channel quality. For example, mobile terminals may detect a signal-to-interference ratio every time slot and use that quality measurement for purposes of selecting a maximum transmission rate for the next time slot. The transmit power might be changed by an incremental amount once every ten time slots. By only gradually changing the base station transmit power, the accuracy of the mobile terminal channel quality estimates is not significantly affected. Moreover, if there is a relatively low transmission load, the base station does not waste resources or generate unnecessary interference by transmitting at maximum power.

Claims

1. A first radio station configured to communicate with a second radio station over a radio interface, comprising:

signal processing and radio transceiving circuitry;

a transmit buffer storing data packets for transmission to the second radio station and coupled to the signal processing and radio transceiving circuitry; and

data processing circuitry, coupled to the transmit buffer and to the signal processing and radio transceiving circuitry, configured to adjust the transmit power at which the data packets are transmitted by the radio transceiving circuitry to the second radio station based on a transmission load over a predetermined time period,

wherein the transmission load corresponds to an amount of data transmitted from or to be transmitted from the first radio station to the second radio station, and

wherein the data processing circuitry is configured to perform the following tasks;

detecting a first amount of packet data currently stored in the transmit buffer;

comparing the first amount of packet data with a second amount of packet data previously detected in the transmit buffer; and

determining an average transmission load using the first and second amounts of packet data.

2. The first radio station in claim 1, wherein the predetermined time period is greater than one time slot of information in which packet data are sent.

3. The first radio station in claim 1, wherein when the transmission load is increasing, the data processing circuitry is configured to control the radio transceiving circuitry to transmit the packet data at a higher transmit power, and wherein when the transmission load is decreasing, the data processing circuitry is configured to control the radio transceiving circuitry to transmit the packet data at a lower transmit power.

4. The radio station in claim 1, wherein if the first amount of data exceeds the second amount of data, then the data processing circuitry is configured to control the radio transceiving circuitry to increase by an incremental amount the transmit power of the transceiving circuitry.

5. The radio station in claim 1, wherein if the first amount of data does not exceed the second amount of data, then the data processing circuitry is configured to control the radio transceiving circuitry to decrease by a decremental amount the transmit power of the transceiving circuitry.

6. The radio station in claim 1, wherein the first radio station is a mobile terminal and the second radio station is a base station.

7. The radio station in claim 1, wherein the first radio station is a base station and the second radio station is a mobile terminal.

8. The radio station in claim 7, wherein the base station includes plural sectors, at least one of the sectors including:

signal processing and radio transceiving circuitry;

a transmit buffer storing data packets for transmission to the mobile terminal and coupled to the signal processing and radio transceiving circuitry; and

data processing circuitry, coupled to the transmit buffer and to the signal processing and radio transceiving circuitry, configured to adjust the transmit power at which the data packets are transmitted by the radio transceiving circuitry to the second radio station based on a transmission load over a predetermined time period associated with the communication between the first radio station and the second radio station.

9. A first radio station configured to communicate with a second radio station over a radio interface, comprising:

signal processing and radio transceiving circuitry;

a transmit buffer storing data packets for transmission to the second radio station and coupled to the signal processing and radio transceiving circuitry; and

data processing circuitry, coupled to the transmit buffer and to the signal processing and radio transceiving circuitry, configured to adjust the transmit power at which the data packets are transmitted by the radio transceiving circuitry to the second radio station based on a transmission load over a predetermined time period,

wherein the transmission load corresponds to an amount of data transmitted from or to be transmitted from the first radio station to the second radio station, and

wherein the adjustment to the transmit power occurs less frequently than a determination by the mobile terminal of a signal quality of a received base station transmission.

10. A base station transmitting information over a radio interface to mobile terminals, wherein the base station is configured to gradually adjust the power that data is transmitted to a first mobile terminal based on a transmission load corresponding to an amount of data transmitted from or to be transmitted from the base station to the first mobile terminal,

wherein the radio channel quality is measured by another mobile terminal every second time period, the second time period being shorter than the first time period.

11. The base station in claim 10, wherein the radio channel quality is based on a ratio of a desired signal to undesired signals.

12. The base station in claim 10, wherein as the transmission load increases, the power is increased, and as the transmission load decreases, the power is decreased.

13. The base station in claim 10, further comprising plural sectors, at least one of the sectors being configured to gradually adjust the power that data is transmitted to a first mobile terminal based a transmission load associated with the communication between the one base station sector and the mobile terminal so that a radio channel quality influenced by the one base station sector data transmission to the first mobile terminal is not significantly affected by the transmit power adjustment.

14. A base station transmitting information over a radio interface to mobile terminals, wherein the base station is configured to gradually adjust the power that data is transmitted to a first mobile terminal based on a transmission load corresponding to an amount of data transmitted from or to be transmitted from the base station to the first mobile terminal,

wherein the transmission load includes an average transmission load over a first time period, and

wherein the average transmission load takes into account an amount of dummy signals transmitted to or to be transmitted from the first mobile terminal.

15. A method for regulating a transmit power of a first radio station transmitting to a second radio station over a radio interface, comprising:

determining a data transmission load corresponding to an amount of data transmitted from or to be transmitted from the first radio station to the second radio station for a predetermined time period, and

regulating the transmit power of the first radio station transmitting to the second radio station based on the determined data transmission loads,

wherein the second radio station determines a signal quality of a first radio station transmission, and wherein the regulating step occurs less frequently than the signal quality determination by the second radio station.

16. The method in claim 15, wherein the determining and regulating are performed in the base station.

17. The method in claim 16, wherein the base station includes a base station sector.

18. The method in claim 15, wherein the determining and regulating are performed in a base station controller controlling plural base stations.

19. The method in claim 15, wherein the data transmission load is an average data transmission load based on an amount of data packets transmitted to or to be transmitted to the second radio station over a current time period.

20. The method in claim 19, wherein the average data transmission load is based on a number of data symbols transmitted to or to be transmitted to the second radio station over a previous time period.

21. The method in claim 20, wherein when the average transmission load is higher, the transmit power is higher, and wherein when the average transmission load is lower, the transmit power is lower.

22. The method in claim 15, wherein the predetermined time period is greater than one time slot of information in which data are sent.

23. The method in claim 15, wherein the determining and regulating steps are performed for a base station transmitting to a mobile terminal.

24. The method claim 15, wherein the first radio station is a terminal and the second radio station is a base station.

25. A method for regulating a transmit power of a first radio station transmitting to a second radio station over a radio interface, comprising:

determining a data transmission load corresponding to an amount of data transmitted from or to be transmitted from the first radio station to the second radio station for a predetermined time period.

regulating the transmit power of the first radio station transmitting to the second radio station based on the determined data transmission load,

wherein the data transmission load is an average data transmission load based on an amount of data packets transmitted to or to be transmitted to the second radio station over a current time period,

wherein the average data transmission load is based on a number of data symbols transmitted to or to be transmitted to the second radio station over a previous time period, and

wherein the average data transmission load takes into account an amount of dummy symbols transmitted to or to be transmitted to the second radio station over a predetermined time period.

26. A method for regulating a transmit power of a first radio station transmitting to a second radio station over a radio interface, comprising:

determining a data transmission load corresponding to an amount of data transmitted from or to be transmitted from the first radio station to the second radio station for a predetermined time period, and

regulating the transmit power of the first radio station transmitting to the second radio station based on the determined data transmission load, the method further comprising;

detecting a first amount of data currently buffered to be transmit to the second radio station;

comparing the first amount of data with a second amount of data previously transmitted to the second radio station;

determining the data transmission load using the first and second amounts of packet data.

27. The method in claim 26, wherein if the first amount of data exceeds the second amount of data, increasing by an incremental amount the transmit power.

28. The method in claim 27, wherein if the first amount of data does not exceed the second amount of data, decreasing by a decremental amount the transmit power.