METHOD AND APPARATUS FOR INTERFERENCE CANCELLATION BY A USER EQUIPMENT USING BLIND DETECTION

• US 20140098773A1
• Filed: 12/12/2013
• Published: 04/10/2014
• Est. Priority Date: 11/04/2011
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: YOO, Taesang, LUO, Tao, WEI, Yongbin, MALLADI, Durga Prasad, SCHOENEICH, Hendrik, RAJIH, Myriam
• Granted Patent: US 9,723,496 B2
• Time in Patent Office: Days
• US Class Current: 370/329
• CPC Class Codes: H04B 7/0678 using different spreading codes between antennas code allocation H04J13/16
• CPC Class Codes: H04B 7/068 using space frequency diversity space-frequency coding H04L1/0606
• CPC Class Codes: H04B 7/0842 Weighted combining
• CPC Class Codes: H04J 11/005 of intercell interference
• CPC Class Codes: H04L 5/0058 Allocation criteria
• CPC Class Codes: H04W 24/02 Arrangements for optimising operational condition

Abstract

In order to cancel any interference due to the second signal (e.g., from a non-serving cell) from a signal received at a UE, without receiving additional control information, the UE blindly estimates parameters associated with decoding the second signal. This may include determining a metric based on sets of symbols associated with the signals in order to determine parameters for the second signal, e.g., the transmission mode, modulation format, and/or spatial scheme of the second signal. The parameters for the signal may be determined based on a comparison of the metric with a threshold. When a spatial scheme and a modulation format is unknown, the blind estimation may include determining a plurality of constellations of possible transmitted modulated symbols associated with a potential spatial scheme and modulation format combination. Interference cancellation can be performed using the constellations and a corresponding probability weight.

Claims

1. A method of wireless communication at a user equipment (UE), comprising:

receiving a signal, the received signal comprising at least a first signal and a second signal, the first signal and the second signal originating from a same cell;

blindly estimating parameters associated with decoding the second signal, the blind estimation including detecting parameters associated with at least one of a modulation format, a spatial scheme, resource allocation information, and a traffic to pilot ratio of the second signal; and

processing the received signal based on the blindly estimated parameters.

2. The method of claim 1, wherein processing the received signal comprises cancelling interference from the received signal due to the second signal, the interference cancellation being based on the blindly estimated parameters.

3. The method of claim 1, wherein:

the received signal comprises at least one of a downlink shared channel and a control channel from a cell; and

processing the received signal comprises cancelling symbols from the received signal, the cancelled symbols being symbols from the second signal.

4. The method of claim 3, wherein the first signal and the second signal originate from a serving cell.

5. The method of claim 1, wherein blindly estimating parameters associated with the second signal comprises determining a transmission technique of the second signal by determining whether the second signal is based on a cell specific reference signal (CRS) or a UE specific reference signal (UE-RS).

6. The method of claim 5, wherein blindly estimating parameters associated with the second signal further comprises,

determining a spatial scheme for the second signal.

7. The method of claim 6, wherein blindly estimating parameters associated with the second signal further comprises,

determining a modulation format of the second signal.

8. The method of claim 7, wherein the determination of the transmission technique of the second signal is made prior to the determination of the spatial scheme and the modulation format of the second signal, and

wherein the determination of the spatial scheme and the modulation format of the second signal are made based, at least in part, on the determination of the transmission technique of the second signal.

9. The method of claim 7, wherein determining the modulation format for the second signal comprises,

determining a plurality of probabilities corresponding to probabilities that the modulation format of the second signal is each one of the allowed modulation formats, where the allowed modulation formats may include binary phase shift keying (BPSK), quadrature phase shift keying (QPSK), quadrature amplitude modulation (QAM) of different modulation orders, and phase-shift keying (PSK) of different modulation orders.

10. The method of claim 7, wherein determining a modulation format of the second signal comprises,

determining whether the modulation format is one of quadrature phase shift keying (QPSK), quadrature amplitude modulation (QAM) of a certain modulation order, and phase-shift keying (PSK) of a certain modulation order.

11. The method of claim 10, wherein the determination of the transmission technique provides weighted probabilities associated with a plurality of transmission techniques, and

the method further comprises,

cancelling interference due to the second signal from the received signal based the weighted probabilities associated with the plurality of transmission techniques.

12. The method of claim 1, wherein the signal comprises a first set of symbols and a second set of symbols, and wherein blindly estimating parameters associated with decoding the second signal further comprises,

determining a metric based on the first set of symbols and the second set of symbols;

comparing the metric with a threshold; and

determining the spatial scheme associated with the second signal based on the comparison.

13. The method of claim 1, wherein blindly estimating parameters associated with decoding the second signal further comprises,

determining that at least one of a spatial scheme and a modulation format is unknown;

determining a plurality of constellations, each constellation comprising a plurality of possible transmitted modulated symbols associated with a potential spatial scheme and modulation format combination; and

determining a probability weight for each constellation,

wherein processing the received signal comprises cancelling interference from the received signal due to the second signal by performing symbol level interference cancellation using the determined plurality of constellations and the determined constellation probability weights.

14. An apparatus for wireless communication, comprising:

means for receiving a signal, the received signal comprising at least a first signal and a second signal, the first signal and the second signal originating from a same cell;

means for blindly estimating parameters associated with decoding the second signal; and

means for processing the received signal based on the blindly estimated parameters.

15. The apparatus of claim 14, wherein the means for processing is configured to cancel interference from the received signal due to the second signal, the interference cancellation being based on the blindly estimated parameters.

16. The apparatus of claim 14, wherein the means for blindly estimating parameters comprises,

means for detecting parameters associated with at least one of a transmission mode, a modulation format, a spatial scheme, resource allocation information, and a traffic to pilot ratio of the second signal.

17. The apparatus of claim 16, wherein the first signal and the second signal originate from a serving cell,

wherein the received signal comprises at least one of a downlink shared channel and a control channel from the serving cell, and

wherein the means for processing cancels symbols from the received signal due to the second signal.

18. The apparatus of claim 14, wherein the means for blindly estimating parameters associated with the second signal determines a transmission technique of the second signal.

19. The apparatus of claim 18, wherein the means for blindly estimating parameters associated with the second signal determines a spatial scheme for the second signal.

20. The apparatus of claim 19, wherein the means for determining the spatial scheme for the second signal determines whether the second signal uses a transmit diversity transmission, a rank 1 transmission, or a rank 2 transmission, and

wherein the means for determining the spatial scheme for the second signal determines which precoding matrix indicator (PMI) is used for the second signal, when it is determined that the second signal uses a rank 1 transmission.

21. The apparatus of claim 19, wherein the means for determining the spatial scheme for the second signal determines a plurality of probabilities corresponding to likelihoods that the second signal is a space frequency block coding (SFBC) transmission, a rank 1 transmission, and a rank 2 transmission.

22. The apparatus of claim 19, wherein the means for blindly estimating parameters associated with the second signal determines a modulation format of the second signal.

23. The apparatus of claim 22, wherein the determination of the transmission technique provides weighted probabilities associated with a plurality of transmission techniques, and wherein the means for processing cancels interference due to the second signal from the received signal based the weighted probabilities associated with the plurality of transmission techniques.

24. The apparatus of claim 14, wherein the signal comprises a first set of symbols and a second set of symbols, and wherein the means for blindly estimating parameters associated with decoding the second signal,

determines a metric based on the first set of symbols and the second set of symbols;

compares the metric with a threshold; and

determines the spatial scheme associated with the second signal based on the comparison.

25. The apparatus of claim 14, wherein the means for blindly estimating parameters associated with decoding the second signal,

determines that at least one of a spatial scheme and a modulation format is unknown;

determines a plurality of constellations, each constellation comprising a plurality of possible transmitted modulated symbols associated with a potential spatial scheme and modulation format combination; and

determines a probability weight for each constellation, and

wherein the means for processing cancels interference from the received signal due to the second signal by performing symbol level interference cancellation using the determined plurality of constellations and the determined constellation probability weights.

26. A computer program product, comprising:

a computer-readable medium comprising code for;

receiving a signal, the received signal comprising at least a first signal and a second signal, the first signal and the second signal originating from a same cell;

blindly estimating parameters associated with decoding the second signal; and

processing the received signal based on the blindly estimated parameters.

27. The computer program product of claim 26, the code for processing the received signal being configured to cancel interference from the received signal due to the second signal, the interference cancellation being based on the blindly estimated parameters.

28. An apparatus for wireless communication, comprising:

a processing system configured to;

receive a signal, the received signal comprising at least a first signal and a second signal, the first signal and the second signal originating from a same cell;

blindly estimate parameters associated with decoding the second signal; and

process the received signal based on the blindly estimated parameters.

29. The apparatus of claim 28, wherein the processing system configured to process the received signal is configured to cancel interference from the received signal due to the second signal, the interference cancellation being based on the blindly estimated parameters.