METHODS AND APPARATUS FOR BLIND INTERFERENCE DECREASE/CANCELLATION TECHNIQUES

• US 20130176881A1
• Filed: 03/01/2013
• Published: 07/11/2013
• Est. Priority Date: 07/29/2009
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Fan, Zhifei, Xu, Hao
• Granted Patent: US 9,319,151 B2
• Time in Patent Office: Days
• US Class Current: 370/252
• CPC Class Codes: H04B 1/7105 Joint detection techniques, e.g. linear detectors
• CPC Class Codes: H04B 15/00 Suppression or limitation of noise or interference by means associated with receiver H04B1/10
• CPC Class Codes: H04B 2201/70702 Intercell-related aspects
• CPC Class Codes: H04L 25/0328 with interference cancellation circuitry adaptations for interference cancellation within a sequence estimator H04L25/03305; interference related aspects of direct sequence spread spectrum H04B1/7097; interference related aspects of frequency hopping spread spectrum H04B1/715; see also H04B1/10
• CPC Class Codes: H04W 72/20 Control channels or signalling for resource management

Abstract

A method, an apparatus, and a computer program product for wireless communication are provided in which one or more semi-static parameters associated with at least one neighboring eNode B (eNB) and an interfering user equipment (UE) are detected, at an eNB, and a blind interference reduction scheme based on the one or more detected semi-static parameters to reduce a signal from the interfering UE is applied.

Claims

1. A method of wireless communication, comprising:

obtaining, at an eNodeB (eNB), one or more semi-static parameters identifying at least one neighboring eNB and an interfering UE; and

reducing signal interference from a signal generated by the interfering UE, at the eNB, by applying a blind interference reduction scheme.

2. The method of claim 1, wherein obtaining the one or more semi-static parameters comprises at least one of:

detecting the one or more semi-static parameters, the detecting including monitoring network signaling associated with the at least one neighboring eNB and the interfering user UE;

receiving the one or more semi-static parameters via a backhaul; and

receiving the one or more semi-static parameters via a report from a UE associated with the eNB.

3. The method of claim 1, wherein the one or more semi-static parameters includes at least one of:

an eNB cell ID, a network identifier of the interfering UE, and a resource ID of the interfering UE.

4. The method of claim 3, wherein at least one of the following is unknown:

a payload size, or whether the interfering UE is sending a control channel quality indicator (CQI) in a subframe.

5. The method of claim 3, further comprising deriving at least one of the following from the one or more semi-static parameters:

a root sequence, a radio bearer location, a cyclic shift index per localized frequency division multiplexing symbol, and a scrambling sequence.

6. The method of claim 2, wherein applying the blind interference reduction scheme comprises:

identifying an interference reduction order of the at least one neighboring eNB; and

processing the at least one neighboring eNB in accordance with the interference reduction order by;

decoding a received signal from the interfering UE assuming a maximum payload size;

reconstructing a transmit signal of the interfering UE from the decoded signal; and

detecting a discontinuous transmission in the reconstructed transmit signal.

7. The method of claim 6, wherein identifying an interference reduction order of the at least one neighboring eNB further comprises:

estimating an average noise a neighboring eNB observes from the interfering UE; and

creating an order of the blind interference reduction scheme by ordering the at least one neighboring eNB according to the estimated average noise.

8. The method of claim 6, wherein detecting a discontinuous transmission comprises:

creating a residue signal by removing the reconstructed transmit signal from the received signal;

calculating an energy of the received signal and an energy of the residue signal;

calculating a ratio of the received signal energy to the residue signal energy;

comparing the ratio with a threshold; and

declaring a discontinuous transmission if the ratio is above the threshold.

9. The method of claim 1, wherein the one or more semi-static parameters comprise an eNB cell ID and a network identifier of the interfering UE.

10. The method of claim 9, wherein at least one of the following is unknown:

a payload size, a cyclic shift index per localized frequency division multiplexing symbol, and whether the interfering UE is sending a control CQI in a subframe.

11. The method of claim 9, further comprising deriving at least one of the following from the one or more semi-static parameters:

a root sequence, common shift offsets for each localized frequency division multiplexing symbol in subframe, and a scrambling sequence.

12. The method of claim 9, wherein applying the blind interference reduction scheme comprises:

determining a resource ID of the interfering UE;

identifying an interference reduction order of the at least one neighboring eNB;

decoding a signal from the interfering UE;

reconstructing a transmit signal of the interfering UE; and

detecting a discontinuous transmission from the reconstructed signal.

13. The method of claim 12, wherein determining a resource ID of the interfering UE comprises:

estimating an average noise for the interfering UE for each of a plurality of possible cyclic shift indices;

ordering the noise estimates according to their noise levels; and

assigning to the interfering UE a cyclic shift index that represents the lowest noise level estimate.

14. The method of claim 12, wherein decoding a signal from the interfering UE comprises:

determining if there are one or more interfering UEs; and

if there is a single interfering UE;

setting the maximum payload size equal to a predetermined number; and

decoding a signal from the interfering UE using the maximum payload size;

or

if there is more than one interfering UE;

decoding the signal of each interfering UE using a plurality of known scrambling codes;

calculating correlations during the decoding; and

selecting the decoded signal corresponding to the maximum number of correlations.

15. The method of claim 1, wherein the one or more semi-static parameters includes an eNB cell ID.

16. The method of claim 15, wherein at least one of the following is unknown:

a payload size, a cyclic shift index per localized frequency division multiplexing symbol, whether the interfering UE is sending a control CQI in a subframe, and a scrambling sequence.

17. The method of claim 15, further comprising deriving at least one of the following from the one or more semi-static parameters:

a root sequence, and common shift offsets for each localized frequency division multiplexing symbol in subframe.

18. The method of claim 15, wherein applying the blind interference reduction scheme comprises:

identifying an interference reduction order of the at least one neighboring eNB;

decoding a signal of an interfering UE using a log-likelihood ratio;

reconstructing a transmit signal of the interfering UE from the decoded signal to form a reconstructed signal; and

detecting a discontinuous transmission from the reconstructed signal.

19. An apparatus for wireless communication, comprising:

means for obtaining, at an eNodeB (eNB), one or more semi-static parameters identifying at least one neighboring eNB and an interfering UE; and

means for reducing signal interference from a signal generated by the interfering UE, at the eNB, by applying a blind interference reduction scheme.

20. The apparatus of claim 19, wherein the means for obtaining the one or more semi-static parameters comprises at least one of:

means for detecting the one or more semi-static parameters, the detecting including monitoring network signaling associated with the at least one neighboring eNB and the interfering UE;

means for receiving the one or more semi-static parameters via a backhaul; and

means for receiving the one or more semi-static parameters via a report from a UE associated with the eNB.

21. The apparatus of claim 19, wherein the one or more semi-static parameters includes at least one of:

an eNB cell ID, a network identifier of the interfering UE, and a resource ID of the interfering UE.

22. The apparatus of claim 21, wherein at least one of the following is unknown:

a payload size, or whether the interfering UE is sending a control channel quality indicator (CQI) in a subframe.

23. The apparatus of claim 21, further comprising means for deriving at least one of the following from the one or more semi-static parameters:

a root sequence, a radio bearer location, a cyclic shift index per localized frequency division multiplexing symbol, and a scrambling sequence.

24. The apparatus of claim 21, wherein the means for reducing signal interference from a signal generated by the interfering UE by applying a blind interference reduction scheme, comprises:

means for identifying an interference reduction order of the at least one neighboring eNB; and

means for processing the at least one neighboring eNB in accordance with the interference reduction order including;

means for decoding a received signal from the interfering UE assuming a maximum payload size;

means for reconstructing a transmit signal of the interfering UE from the decoded signal; and

means for detecting a discontinuous transmission in the reconstructed transmit signal.

25. The apparatus of claim 24, wherein the means for identifying an interference reduction order of the at least one neighboring eNB comprises:

means for estimating an average noise a neighboring eNB observes from the interfering UE; and

means for creating an order of the blind interference reduction by ordering the neighbor eNB according to the estimated average noise.

26. The apparatus of claim 24, wherein the means for detecting a discontinuous transmission comprises:

means for creating a residue signal by removing the reconstructed transmit signal from the received signal;

means for calculating an energy of the received signal and an energy of the residue signal;

means for calculating a ratio of the received signal energy to the residue signal energy;

means for comparing the ratio with a threshold; and

means for declaring a discontinuous transmission if the ratio is above the threshold.

27. The apparatus of claim 19, wherein the one or more semi-static parameters comprise an eNB cell ID and a network identifier of the interfering UE.

28. The apparatus of claim 27, wherein at least one of the following is unknown:

a payload size, a cyclic shift index per localized frequency division multiplexing symbol, whether the interfering UE is sending a control channel quality indicator (CQI) in a subframe, and a scrambling sequence.

29. The apparatus of claim 27, further comprising means for deriving at least one of the following from the one or more semi-static parameters:

a root sequence, common shift offsets for each localized frequency division multiplexing symbol in subframe, and a scrambling sequence.

30. The apparatus of claim 27, wherein the means for reducing signal interference from a signal generated by the interfering UE by applying a blind interference reduction scheme comprises:

means for determining a resource ID of the interfering UE;

means for identifying an interference reduction order of the at least one neighboring eNB;

means for decoding a signal from the interfering UE;

means for reconstructing a transmit signal of the interfering UE; and

means for detecting a discontinuous transmission from the reconstructed signal.

31. The apparatus of claim 30, wherein the means for determining a resource ID of the interfering UE comprises:

means for estimating an average noise for the interfering UE for each of a plurality of possible cyclic shift indices;

means for ordering the noise estimates according to their noise levels; and

means for assigning to the interfering UE a cyclic shift index that represents the lowest noise level estimate.

32. The apparatus of claim 30, wherein the means for decoding a signal from the interfering UE comprises:

means for determining if there are one or more interfering UEs; and

if there is a single interfering UE;

means for setting the maximum payload size equal to a predetermined number; and

means for decoding a signal from the interfering UE using the maximum payload size;

or

if there is more than one interfering UE;

means for decoding the signal of each interfering UE using a plurality of known scrambling codes;

means for calculating correlations during the decoding; and

means for selecting the decoded signal corresponding to the maximum number of correlations.

33. The apparatus of claim 19, wherein the one or more semi-static parameters includes an eNB cell ID.

34. The apparatus of claim 33, wherein at least one of the following is unknown:

a payload size, a cyclic shift index per localized frequency division multiplexing symbol, whether the interfering UE is sending a control CQI in a subframe, and a scrambling sequence.

35. The apparatus of claim 33, further comprising means for deriving at least one of the following from the one or more semi-static parameters:

a root sequence detected using the eNB cell ID, and common shift offsets for each localized frequency division multiplexing symbol in subframe.

36. The apparatus of claim 33, wherein the means for reducing signal interference from a signal generated by the interfering UE by applying a blind interference reduction scheme comprises:

means for identifying an interference reduction order of the at least one neighboring eNB;

means for decoding a signal of an interfering UE using a log-likelihood ratio;

means for reconstructing a transmit signal of the interfering UE from the decoded signal to form a reconstructed signal; and

means for detecting a discontinuous transmission from the reconstructed signal.

37. A computer program product, comprising:

a non-transitory computer-readable medium comprising code for;

obtaining, at an eNodeB (eNB), one or more semi-static parameters identifying at least one neighboring eNB and an interfering user equipment (UE); and

reducing signal interference from a signal generated by the interfering UE, at the eNB, by applying a blind interference reduction.

38. The computer program product of claim 37, wherein the code for obtaining the one or more semi-static parameters comprises at least one of:

code for detecting the one or more semi-static parameters, the detecting including monitoring network signaling associated with the at least one neighboring eNB and the interfering UE;

code for receiving the one or more semi-static parameters via a backhaul;

or

code for receiving the one or more semi-static parameters via a report from a UE associated with the eNB.

39. The computer program product of claim 37, wherein the one or more semi-static parameters includes at least one of:

an eNB cell ID, a network identifier of the interfering UE, and a resource ID of the interfering UE.

40. The computer program product of claim 39, wherein at least one of the following is unknown:

a payload size, and whether the interfering UE is sending a control CQI in a subframe.

41. The computer program product of claim 39, further comprising code for deriving at least one of the following from the one or more semi-static parameters:

a root sequence, a radio bearer location, a cyclic shift index per localized frequency division multiplexing symbol, and a scrambling sequence.

42. The computer program product of claim 39, wherein the code for reducing signal interference applies the blind interference reduction scheme using code for:

identifying an interference reduction order of the at least one neighboring eNB; and

processing the at least one neighboring eNB in accordance with the interference reduction order by;

decoding a received signal from the interfering UE assuming a maximum payload size;

reconstructing a transmit signal of the interfering UE from the decoded signal; and

detecting a discontinuous transmission in the reconstructed transmit signal.

43. The computer program product of claim 42, wherein the code for identifying an interference reduction order of the at least one neighboring eNB comprises code for:

estimating an average noise a neighboring eNB observes from the interfering UE; and

creating an order of the blind interference reduction by ordering the neighbor eNB according to the estimated average noise.

44. The computer program product of claim 42, wherein the code for detecting a discontinuous transmission comprises code for:

creating a residue signal by removing the reconstructed transmit signal from the received signal;

calculating an energy of the received signal and an energy of the residue signal;

calculating a ratio of the received signal energy to the residue signal energy;

comparing the ratio with a threshold; and

declaring a discontinuous transmission if the ratio is above the threshold.

45. The computer program product of claim 37, wherein the one or more semi-static parameters comprise an eNB cell ID and a network identifier of the interfering UE.

46. The computer program product of claim 45, wherein at least one of the following is unknown:

a payload size, a cyclic shift index per localized frequency division multiplexing symbol or whether the interfering UE is sending a control channel quality indicator (CQI) in a subframe.

47. The computer program product of claim 45, further comprising code for deriving at least one of the following from the one or more semi-static parameters:

a root sequence, common shift offsets for each localized frequency division multiplexing symbol in subframe, and a scrambling sequence.

48. The computer program product of claim 45, wherein the code for reducing signal interference applies the blind interference reduction scheme using code for:

determining a resource ID of the interfering UE;

identifying an interference reduction order of the at least one neighboring eNB;

decoding a signal from the interfering UE;

reconstructing a transmit signal of the interfering UE; and

detecting a discontinuous transmission from the reconstructed signal.

49. The computer program product of claim 48, wherein the code for determining a resource ID of the interfering UE comprises code for:

estimating an average noise for the interfering UE for each of a plurality of possible cyclic shift indices;

ordering the noise estimates according to their noise levels; and

assigning to the interfering UE a cyclic shift index that represents the lowest noise level estimate.

50. The computer program product of claim 48, wherein the code for decoding a signal from the interfering UE comprises code for:

determining if there are one or more interfering UEs; and

if there is a single interfering UE;

setting the maximum payload size equal to a predetermined number; and

decoding a signal from the interfering UE using the maximum payload size;

or

if there is more than one interfering UE;

decoding the signal of each interfering UE using a plurality of known scrambling codes;

calculating correlations during the decoding; and

selecting the decoded signal corresponding to the maximum number of correlations.

51. The computer program product of claim 37, wherein the one or more semi-static parameters includes an eNB cell ID.

52. The computer program product of claim 51, wherein at least one of the following is unknown:

a payload size, a cyclic shift index per localized frequency division multiplexing symbol, whether the interfering UE is sending a control CQI in a subframe, and a scrambling sequence.

53. The computer program product of claim 51, further comprising code for deriving at least one of the following from the one or more semi-static parameters:

a root sequence detected, and common shift offsets for each localized frequency division multiplexing symbol in subframe.

54. The computer program product of claim 51, wherein the code for reducing signal interference applies the blind interference reduction scheme using code for:

identifying an interference reduction order of the at least one neighboring eNB;

decoding a signal of an interfering UE using a log-likelihood ratio;

reconstructing a transmit signal of the interfering UE from the decoded signal to form a reconstructed signal; and

detecting a discontinuous transmission from the reconstructed signal.

55. An apparatus for wireless communication, comprising:

at least one processor; and

a memory coupled to the at least one processor, wherein the at least one processor is configured to;

obtain, at an eNodeB (eNB), one or more semi-static parameters identifying at least one neighboring eNB and an interfering user equipment (UE); and

apply, at the eNB, a blind interference reduction scheme to reduce a signal from the interfering UE.

56. The apparatus of claim 55, wherein to obtain the one or more semi-static parameters, the processor is configured to:

detect the one or more semi-static parameters, the detecting including monitoring network signaling associated with the at least one neighboring eNB and the interfering UE;

receive the one or more semi-static parameters via a backhaul; and

receive the one or more semi-static parameters via a report from a UE associated with the eNB.

57. The apparatus of claim 55, wherein the one or more semi-static parameters includes at least one of:

an eNB cell ID, a network identifier of the interfering UE, and a resource ID of the interfering UE.

58. The apparatus of claim 57, wherein at least one of the following is unknown:

a payload size, and whether the interfering UE is sending a control CQI in a subframe.

59. The apparatus of claim 57, wherein the at least one processor is configured to derive at least one of the following from the one or more semi-static parameters:

a root sequence, a radio bearer location, a cyclic shift index per localized frequency division multiplexing symbol detected, and a scrambling sequence.

60. The apparatus of claim 57, wherein to apply a blind interference reduction scheme, the at least one processor is configured to:

identify an interference reduction order of the at least one neighboring eNB; and

process the at least one neighboring eNB in accordance with the interference reduction order by being configured to;

decode a received signal from the interfering UE assuming a maximum payload size;

reconstruct a transmit signal of the interfering UE from the decoded signal; and

detect a discontinuous transmission in the reconstructed transmit signal.

61. The apparatus of claim 60, wherein to identify the interference reduction order of the at least one neighboring eNB, the at least one processor is configured to:

estimate an average noise a neighboring eNB observes from the interfering UE; and

create an order of the blind interference reduction by ordering the neighbor eNB according to the estimated average noise.

62. The apparatus of claim 60, wherein to detect a discontinuous transmission in the reconstructed transmit signal, the at least one processor is configured to:

create a residue signal by removing the reconstructed transmit signal from the received signal;

calculate an energy of the received signal and an energy of the residue signal;

calculate a ratio of the received signal energy to the residue signal energy;

compare the ratio with a threshold; and

declare a discontinuous transmission if the ratio is above the threshold.

63. The apparatus of claim 55, wherein the one or more semi-static parameters includes an eNB cell ID and a network identifier of the interfering UE.

64. The apparatus of claim 63, wherein at least one of the following is unknown:

a payload size, a cyclic shift index per localized frequency division multiplexing symbol, or whether the interfering UE is sending a control CQI in a subframe.

65. The apparatus of claim 63, wherein the at least one processor is further configured to derive at least one of the following from the one or more semi-static parameters:

a root sequence, common shift offsets for each localized frequency division multiplexing symbol in subframe, and a scrambling sequence.

66. The apparatus of claim 63, wherein to apply a blind interference reduction scheme, the at least one processor is configured to:

determine a resource ID of the interfering UE;

identify an interference reduction order of the at least one neighboring eNB;

decode a signal from the interfering UE;

reconstruct a transmit signal of the interfering UE; and

detect a discontinuous transmission from the reconstructed signal.

67. The apparatus of claim 66, wherein to determine a resource ID of the interfering UE, the at least one processor is configured to:

estimate an average noise for the interfering UE for each of a plurality of possible cyclic shift indices;

order the noise estimates according to their noise levels; and

assign to the interfering UE a cyclic shift index that represents the lowest noise level estimate.

68. The apparatus of claim 66, wherein to decode a signal from the interfering UE, the at least one processor is configured to:

determine if there are one or more interfering UEs; and

if there is a single interfering UE;

set the maximum payload size equal to a predetermined number; and

decode a signal from the interfering UE using the maximum payload size; and

if there is more than one interfering UE;

decode the signal of each interfering UE using a plurality of known scrambling codes;

calculate correlations during the decoding; and

select the decoded signal corresponding to the maximum number of correlations.

69. The apparatus of claim 55, wherein the one or more semi-static parameters includes an eNB cell ID.

70. The apparatus of claim 69, wherein at least one of the following is unknown:

a payload size, a cyclic shift index per localized frequency division multiplexing symbol, whether the interfering UE is sending a control CQI in a subframe, and a scrambling sequence.

71. The apparatus of claim 69, wherein the at least one processor is further configured to derive at least one of the following from the one or more semi-static parameters:

a root sequence, and common shift offsets for each localized frequency division multiplexing symbol in subframe.

72. The apparatus of claim 69, wherein to apply a blind interference reduction scheme, the at least one processor is configured to:

identify an interference reduction order of the at least one neighboring eNB;

decode a signal of an interfering UE using a log-likelihood ratio;

reconstruct a transmit signal of the interfering UE from the decoded signal to form a reconstructed signal; and

detect a discontinuous transmission from the reconstructed signal.