Remote base station with transmit power control

• US 7,574,230 B1
• Filed: 06/21/2004
• Issued: 08/11/2009
• Est. Priority Date: 05/31/2001
• Status: Expired due to Fees

• Current Assignee: Sprint Spectrum LP (Deutsche Telekom AG)
• Original Assignee: Sprint Spectrum LP (Deutsche Telekom AG)
• Inventors: Oh, Dae-Sik, Hayne, Kristin A., Yarkosky, Mark L.
• Primary Examiner(s): Anderson; Matthew D
• Assistant Examiner(s): Safaipour; Bobbak
• Application Number:
  US10/873,588
• Time in Patent Office: 1,877 Days
• Field of Search: 455/522
• US Class Current: 455/522
• CPC Class Codes: H04W 52/283 Power depending on the position of the mobile

Abstract

A method of communicating with a mobile station. The method includes receiving forward link signals from a central base station at a remote base station and transmitting the forward link signals from the remote base station to the mobile station. The method also includes receiving reverse link signals from the mobile station at the remote base station and transmitting the reverse link signals from the remote base station to the central base station. The method further includes cooperatively adjusting a transmission power level for communication between the mobile station and the remote base station.

Claims

1. A remote base station for communicating with a mobile station over an air interface comprising:

a first antenna receiving forward link wireless communication signals from a central base station;

a second antenna receiving reverse link wireless communication signals from the mobile station;

a first transceiver receiving the forward link wireless communication signals from the first antenna and sending the forward link wireless communication signals to the second antenna along a first signal path for transmission to the mobile station;

a second transceiver receiving the reverse link wireless communication signals from the second antenna and sending the reverse link communication signals to the first antenna along a second signal path for transmission to the central base station; and

a power control module coupled to each of the first transceiver and the second transceiver for adjusting a transmission power level for communication between the mobile station and the remote base station, wherein the transmission power level is a remote base station transmission power level used to transmit signals to the mobile station and the power control modules comprises service logic for adjusting the remote base station transmission power level based on an energy level E_b/N_o of the forward link signals received by the mobile station and an estimate of a noise level in the air interface, wherein the energy level E_b/N_o is determined by the mobile station and a value of E_b/N_o is communicated to the remote base station by the mobile station via the second transceiver,

the power control module further sending, to the mobile station, an instruction to transmit reverse link signals at a selected power level, wherein the mobile station responsively transmits reverse link signals at the selected power level.

2. The remote base station of claim 1, wherein the forward link wireless signals are transmitted from the central base station to the remote base station at a substantially fixed transmission power.

3. The remote base station of claim 1, wherein the reverse link signals are transmitted by the remote base station to the central base station at a substantially continuous transmission power.

4. The remote base station of claim 1, wherein the transmission power level is a mobile station transmission power level, and wherein the power control module comprises service logic for:

determining an energy level E_b/N_o of the reverse link signals received from the mobile station; and

determining an adjustment to the mobile station transmission power level based on a comparison of the value of E_b/N_o with a setpoint, wherein the determined adjustment is communicated to the mobile station by the remote base station using the first transceiver.

5. The remote base station of claim 1, wherein the transmission power level is a mobile station transmission power level, and wherein the power control module comprises service logic for:

determining a frame error rate of the reverse link signals received from the mobile station; and

determining an adjustment to a setpoint for the energy level of the mobile station transmission power level based on a comparison of the frame error rate with a threshold value.

6. The remote base station of claim 1, wherein the transmission power level is a remote base station transmission power level, and wherein the power control modules comprises service logic for:

determining an adjustment to a setpoint for the energy level of the remote base station transmission power level based on a frame error rate of the forward link signals received by the mobile station, wherein the frame error rate is determined by the mobile station and communicated to the remote base station via the second transceiver.

7. The remote base station of claim 1, wherein the power control module comprises service logic for:

determining a location of the mobile station;

selecting a power level for communication between the mobile station and the remote base station based on the determined location; and

effecting communication between the remote base station and the mobile station at the selected power level.

8. The remote base station of claim 7, wherein selecting a power level for communication between the mobile station and the remote base station comprises:

referring to a database that correlates geographic locations with power levels; and

selecting from the database, a power level that corresponds with the determined location of the mobile station.

9. The remote base station of claim 8, wherein the selected power level is a mobile station transmit-power level, and wherein effecting communication between the mobile station and the remote base station comprises:

sending, to the mobile station, an instruction to transmit at the mobile station transmit-power level, wherein the mobile station responsively transmits at the mobile station transmit-power level.

10. The remote base station of claim 8, wherein the selected power level is a remote base station transmit-power level, and wherein effecting communication between the mobile station and the remote base station comprises:

setting the remote base station to transmit at the remote base station transmit-power level, wherein the remote base station responsively transmits at the remote base station transmit-power level.

11. A method of communicating with a mobile station, the method comprising:

receiving forward link signals from a central base station at a remote base station;

transmitting the forward link signals to the mobile station over an air interface;

receiving reverse link signals from the mobile station at the remote base station over the air interface;

transmitting the reverse link signals to the central base station; and

cooperatively adjusting a transmission power level for communication between the mobile station and the remote base station by sending, to the mobile station, an instruction to transmit reverse link signals at a selected power level, wherein the mobile station responsively transmits reverse link signals at the selected power level, and wherein the transmission power level includes a remote base station transmit-power level used to transmit signals to the mobile station, and wherein the remote base station transmit-power level is determined based on at least (i) an energy level E_b/N_o of the forward link signals received by the mobile station and communicated to the remote base station by the mobile station, and (ii) an estimate of a noise level in the air interface.

12. The method of claim 11, further comprising:

determining an adjustment to the remote base station transmit-power level based on a comparison of a value of E_b/N_o of the forward link signals received by the mobile station with a setpoint.

13. The method of claim 11, further comprising:

determining an adjustment to a setpoint for the remote base station transmit-power level based on a comparison of the frame error rate of the forward link signals received by the mobile station with a threshold frame error rate.

14. The method of claim 11, wherein the selected power level is determined based on at least one of an energy level E_b/N_o and a frame error rate of the reverse link signals received by the remote base station.

15. The method of claim 14, further comprising:

determining an adjustment to the selected power level based on a comparison of a value of E_b/N_o of the reverse link signals received by the remote base station with a setpoint.

16. The method of claim 14, further comprising:

determining an adjustment to the selected power level based on a comparison of the frame error rate of the reverse link signals received at the remote base station with a threshold frame error rate.

17. The method of claim 11, wherein the forward link signals from the central base station are received at a substantially constant transmission power.

18. The method of claim 11, wherein the reverse link signals are transmitted to the central base station at a substantially constant transmission power.

19. The method of claim 11, wherein cooperatively adjusting a transmission power level for communication between the mobile station and the remote base station comprises:

determining a location of the mobile station;

selecting a power level for communication between the mobile station and the remote base station based on the determined location; and

effecting communication between the remote base station and the mobile station at the selected power level.

20. The method of claim 19, wherein selecting a power level for communication between the mobile station and the remote base station based on the determined location comprises:

referring to a database that correlates geographic locations with power levels; and

selecting from the database a power level that corresponds with the determined location of the mobile station.

21. The method of claim 19, wherein effecting communication between the mobile station and the remote base station comprises:

setting the remote base station to transmit at a remote base station transmit-power level, wherein the remote base station responsively transmits at the remote base station transmit-power level.

22. The method of claim 19, further comprising:

implementing open-loop power control with the selected power level being employed as an initial E_b/N_o setpoint; and

implementing closed-loop power control when the E_b/N_o setpoint matches a measured value of E_b/N_o.

23. A wireless communication system comprising:

a central base station;

a remote base station in communication with the central base station; and

a mobile station in communication with the remote base station over an air interface, the remote base station comprising;

a first antenna receiving forward link wireless communication signals from a central base station;

a second antenna receiving reverse link wireless communication signals from the mobile station;

a first transceiver receiving the forward link wireless communication signals from the first antenna and sending the forward link wireless communication signals the second antenna along a first signal path for transmission to the mobile station;

a second transceiver receiving the reverse link wireless communication signals from the second antenna and sending the reverse link wireless communication signals to the first antenna along a second signal path for transmission to the central base station; and

a power control module coupled to each of the first transceiver and the second transceiver for adjusting a transmission power level for communication between the mobile station and the remote base station, wherein the transmission power level is a remote base station transmission power level used to transmit signals to the mobile station and the power control modules comprises service logic for adjusting the remote base station transmission power level based on an energy level E_b/N_o of the forward link signals received by the mobile station and an estimate of a noise level in the air interface, wherein the energy level E_b/N_o is determined by the mobile station and a value of E_b/N_o is communicated to the remote base station by the mobile station via the second transceiver,

the power control module further sending, to the mobile station, an instruction to transmit reverse link signals at a selected power level, wherein the mobile station responsively transmits reverse link signals at the selected power level.