Determining the Repeater Gain in Dependence of Interference

• US 20120058719A1
• Filed: 05/04/2009
• Published: 03/08/2012
• Est. Priority Date: 05/04/2009
• Status: Active Grant

• Current Assignee: Telefonaktiebolaget LM Ericsson
• Original Assignee: Telefonaktiebolaget LM Ericsson
• Inventors: Gan, Jiansong, Frenger, Pål, Liu, Yin, Zhang, Zhang
• Granted Patent: US 8,862,051 B2
• Time in Patent Office: Days
• US Class Current: 455/10
• CPC Class Codes: H04B 7/15535 Control of relay amplifier gain amplifier gain control in general H03G3/00; gain control reducing self - or loop interference H04B7/15578
• CPC Class Codes: H04B 7/15578 by gain adjustment
• CPC Class Codes: H04B 7/2606 Arrangements for base station coverage control, e.g. by using relays in tunnels
• CPC Class Codes: H04W 52/46 in multi hop networks, e.g. wireless relay networks

Abstract

A method of operating a repeater in a communications system is disclosed, wherein a repeater gain to be used for the amplification of a signal is adjusted in dependence on an estimate of an interference by the repeater and by the receiver. The interference at the receiver is feed back to the relay node.

Claims

1-21. -21. (canceled)

22. A method of performing transmission power control in a communications system that comprises a first node, a second node, and a repeater configured to receive a signal from the first node, amplify the signal, and retransmit the amplified signal so that the amplified signal can be detected by the second node, the method comprising:

determining a desired repeater gain value for amplification of the signal, in dependence on an estimate of interference experienced by the repeater and an estimate of interference experienced by the second node, and under constraints that the desired repeater gain value be below or equal to a maximum gain of the repeater and that a power of the repeater be below or equal to a maximum power of the repeater; and

transmitting, from the second node to the repeater, a set gain command signal that includes information on how a repeater gain of the repeater is to be adjusted in accordance with the determined desired repeater gain value.

23. The method of claim 22, further comprising receiving, in the second node, a repeater interference report signal indicative of an interference measure, and obtaining the estimate of interference experienced by the repeater based on that interference measure.

24. A method implemented by a repeater of a communications system for amplifying and retransmitting a signal received from a first node so that the amplified signal can be detected by a second node, the method comprising adjusting a repeater gain used for amplification of said signal in accordance with a desired repeater gain value that has been determined in dependence on an estimate of interference experienced by the repeater and an estimate of interference experienced by the second node, and under the constraints that the desired repeater gain value be below or equal to a maximum gain of the repeater and that a power of the repeater be below or equal to a maximum power of the repeater.

25. The method of claim 24, further comprising measuring, at the repeater, a received signal strength in dependence on which the interference experienced by the repeater is estimated.

26. The method of claim 25, further comprising transmitting, from the repeater to the second node, a repeater interference report signal indicative of an interference measure obtained from the received-signal-strength measurement.

27. The method of claim 24, further comprising receiving, from the second node, a set gain command signal comprising instructions on how the repeater gain is to be adjusted in accordance with the desired repeater gain value.

28. The method of claim 24, further comprising determining the desired repeater gain value in the repeater.

29. The method of claim 28, further comprising:

measuring a received signal strength and determining the estimate of interference experienced by the repeater based on that measurement;

receiving from the second node a message indicative of the estimate of interference experienced by the second node; and

determining the desired repeater gain value in dependence on the determined estimate of interference experienced by the repeater and the estimate of interference experienced by the second node indicated in the received message.

30. The method of claim 24, wherein the desired repeater gain value is determined as a gain which minimizes a function describing a total weighted power transmitted from the repeater and the first node while providing a target equivalent signal-to-noise-and-interference ratio at the second node.

31. The method of claim 30, wherein a desired transmission power to be used by the first node is determined from the minimum of said function.

32. The method of claim 24, wherein the desired repeater gain value is determined as the smallest of:

a maximum gain of the repeater, a gain corresponding to a maximum power transmitted from the repeater, and a gain corresponding to a maximum part of an equivalent interference at the second node originating from interference at the repeater.

33. The method of claim 24, further comprising determining the desired repeater gain value by:

checking whether the estimate of the interference experienced by the repeater is below an interference threshold; and

if the check indicates that the interference experienced by the repeater is below the interference threshold, setting the desired repeater gain value to a predetermined high repeater gain value.

34. The method of claim 24, further comprising:

checking whether the estimate of the interference experienced by the repeater is above an interference threshold; and

if the check indicates that the interference experienced by the repeater is above the interference threshold, setting a transmission power of the first node to be used for transmission of the signal to a predetermined high first node transmission power value.

35. A repeater in a communications system configured to amplify and retransmit a signal received from a first node so that the amplified signal can be detected by a second node, the repeater comprising a repeater gain adjustment circuit configured to adjust a repeater gain for amplification of the signal in accordance with a desired repeater gain value that has been determined in dependence on an estimate of interference experienced by the repeater and an estimate of interference experienced by the second node, and under the constraints that the desired repeater gain value be below or equal to a maximum gain of the repeater and that a power of the repeater be below or equal to a maximum power of the repeater.

36. The repeater of claim 35, further comprising a signal strength measurement circuit configured to measure a received signal strength in dependence on which the interference experienced by the repeater is estimated.

37. The repeater of claim 36, further comprising an interference report transmit circuit configured to transmit, to the second node, a repeater interference report signal indicative of an interference measure obtained from the received-signal-strength measurement.

38. The repeater of claim 35, further comprising a set gain command receipt circuit configured to receive a set gain command signal comprising instructions on how to adjust the repeater gain in accordance with the desired repeater gain value.

39. The repeater of claim 35, further comprising a repeater gain determination circuit configured to determine the desired repeater gain value.

40. The repeater of claim 39, further comprising an interference report receipt circuit configured to receive a message from the second node indicative of the estimate of interference experienced by the second node, and a signal strength measurement circuit configured to measure a received signal strength and determine the estimate of interference experienced by the repeater based on that measurement, and wherein the repeater gain determination circuit is configured to determine the desired repeater gain value in dependence on the estimates from the interference report receipt circuit and the signal strength measurement circuit.

41. A radio base station in a radio communications system configured to receive a signal that has been amplified by a repeater, wherein the radio base station comprises:

a repeater gain determination circuit configured to determine a desired repeater gain value for amplification of the signal, in dependence on an estimate of interference experienced by the repeater and an estimate of interference experienced by the second node, and under constraints that the desired repeater gain value be below or equal to a maximum gain of the repeater and that a power of the repeater be below or equal to a maximum power of the repeater; and

a set gain command transmit circuit configured to transmit, to the repeater, a set gain command that comprises an instruction on how to adjust a repeater gain of the repeater in accordance with the desired repeater gain value.

42. The radio base station of claim 41, further comprising an interference report receipt circuit configured to receive a repeater interference report signal that is indicative of an interference measure, and to obtain the estimate of the interference experienced by the repeater in dependence on that interference measure.

43. A radio communications system comprising a repeater configured to amplify and retransmit a signal received from a first node so that the amplified signal can be detected by a second node, the repeater comprising a repeater gain adjustment circuit configured to adjust a repeater gain used for amplification of the signal in accordance with a desired repeater gain value that has been determined in dependence on an estimate of interference experienced by the repeater and an estimate of interference experienced by the second node, and under the constraints that the desired repeater gain value be below or equal to a maximum gain of the repeater and that a power of the repeater be below or equal to a maximum power of the repeater.

44. A computer program product stored on a computer readable medium and comprising computer program code that, when executed by a processor of a node in a radio communications system, cause the node to determine a desired value for a gain of a repeater in the system in dependence on an estimate of interference experienced by the repeater and an estimate of interference experienced by a node that is to receive a signal amplified by the repeater, and under constraints that the desired repeater gain value be below or equal to a maximum gain of the repeater and that a power of the repeater be below or equal to a maximum power of the repeater