Advanced signal processors for interference cancellation in baseband receivers

• US 9,172,411 B2
• Filed: 12/16/2013
• Issued: 10/27/2015
• Est. Priority Date: 09/20/2002
• Status: Expired due to Fees

• Current Assignee: III Holdings 1, LLC (Intellectual Ventures LLC)
• Original Assignee: III Holdings 1, LLC (Intellectual Ventures LLC)
• Inventors: McCloud, Michael L., Nagarajan, Vijay
• Primary Examiner(s): Gauthier, Gerald
• Application Number:
  US14/108,333
• Publication Number:
  US 20140341323A1
• Time in Patent Office: 680 Days
• Field of Search: 370/286, 370/342, 375/348, 375/147, 375/148, 375/316, 375/144, 375/259, 375/265, 375/341, 455/67.14
• US Class Current: 1/1
• CPC Class Codes: H04B 1/10 Means associated with receiver for limiting or suppressing noise or interference
• CPC Class Codes: H04B 1/7103 the interference being multiple access interference
• CPC Class Codes: H04B 1/7107 Subtractive interference cancellation
• CPC Class Codes: H04B 1/7115 Constructive combining of multi-path signals, i.e. RAKE receivers
• CPC Class Codes: H04B 1/7117 Selection, re-selection, allocation or re-allocation of paths to fingers, e.g. timing offset control of allocated fingers
• CPC Class Codes: H04B 1/712 Weighting of fingers for combining, e.g. amplitude control or phase rotation using an inner loop
• CPC Class Codes: H04J 11/0023 Interference mitigation or co-ordination direct sequence spread spectrum [DSSS] systems H04B1/7097; frequency hopping H04B1/713; allocation criteria for ingress interference avoidance H04L5/0062; frequency allocation criteria for requirements on out-of-channel emissions H04L5/0066; arrangements for removing intersymbol interference or baseband equalisers H04L25/03006; peak power aspects in multicarrier modulation H04L27/2614; power management H04W52/00; traffic scheduling H04W72/54, H04W72/541
• CPC Class Codes: H04J 13/0003 Code application, i.e. aspects relating to how codes are applied to form multiplexed channels
• CPC Class Codes: H04J 13/20 having an orthogonal variable spreading factor [OVSF]
• CPC Class Codes: H04J 2011/0006 with CDM/CDMA
• CPC Class Codes: H04W 24/06 Testing, supervising or monitoring using simulated traffic

Abstract

An interference canceller comprises a composite interference vector (CIV) generator configured to produce a CIV by combining soft and/or hard estimates of interference, an interference-cancelling operator configured for generating a soft projection operator, and a soft-projection canceller configured for performing a soft projection of the received baseband signal to output an interference-cancelled signal. Weights used in the soft-projection operator are selected to maximize a post-processing SINR.

Claims

1. A method for cancelling interference from a received baseband signal, the method comprising:

generating at least one composite interference vector (CIV) by combining estimates from interfering subchannels, wherein the estimates are derived from at least one of a Rake receiver, an equalizer, a receiver employing receive diversity, a receiver employing transmit diversity combining, or a receiver employing space-time decoding;

generating a soft-cancellation operator; and

performing a soft cancellation of the received baseband signal to output an interference-cancelled signal.

2. The method of claim 1, wherein:

the generating at least one CIV comprises deriving the estimates from the Rake receiver; and

each finger of the Rake receiver is matched to at least one of a time delay or a base station spreading code.

3. The method of claim 1, wherein the generating at least one CIV further comprises generating at least one or more soft estimates corresponding to interfering user subchannels from each base station tracked by a cellular handset.

4. The method of claim 1, wherein the soft cancellation operator comprises a soft-projection matrix generator or an interference-cancelling operator configured for selecting a soft weight that increases a post-processing signal-to-interference-plus-noise-ratio (SINR).

5. The method of claim 1, wherein the generating the at least one CIV comprises deriving the estimates from at least one of a Rake receiver, an equalizer, a receiver employing receive diversity, a receiver employing transmit diversity combining, or a receiver employing space-time decoding.

6. The method of claim 1, wherein the performing the soft cancellation further comprises coupling the interference-cancelled signal to at least one of a combiner or a Rake receiver.

7. An apparatus for cancelling interference from a received baseband signal, wherein the apparatus is configured to perform operations comprising:

generating at least one composite interference vector (CIV) by combining estimates from interfering subchannels, wherein the estimates are derived from at least one of a Rake receiver, an equalizer, a receiver employing receive diversity, a receiver employing transmit diversity combining, or a receiver employing space-time decoding;

generating a soft-cancellation operator; and

performing a soft cancellation of the received baseband signal to output an interference-cancelled signal.

8. The apparatus of claim 7, wherein the apparatus is configured to perform operations comprising:

the generating at least one CIV comprises deriving the estimates from the Rake receiver.

9. The apparatus of claim 8, wherein each finger of the Rake receiver is matched to at least one of a time delay or a base station spreading code.

10. The apparatus of claim 7, wherein the apparatus is configured to perform operations comprising:

the generating at least one CIV further comprises generating at least one or more soft estimates corresponding to interfering user subchannels from each base station tracked by a cellular handset.

11. The apparatus of claim 7, wherein the soft cancellation operator comprises a soft-projection matrix generator or an interference-cancelling operator configured for selecting a soft weight that increases a post-processing signal-to-interference-plus-noise-ratio (SINR).

12. The apparatus of claim 7, wherein the apparatus is configured to perform operations comprising:

wherein the generating the at least one CIV comprises deriving the estimates from at least one of a Rake receiver, an equalizer, a receiver employing receive diversity, a receiver employing transmit diversity combining, or a receiver employing space-time decoding.

13. The apparatus of claim 7, wherein the apparatus is configured to perform operations comprising:

wherein the performing the soft cancellation further comprises coupling the interference-cancelled signal to at least one of a combiner or a Rake receiver.

14. At least one non-transitory computer-readable medium including software that, when executed by at least one processor, causes operations comprising:

generating at least one composite interference vector (CIV) by combining estimates from interfering subchannels, wherein the estimates are derived from at least one of a Rake receiver, an equalizer, a receiver employing receive diversity, a receiver employing transmit diversity combining, or a receiver employing space-time decoding;

generating a soft-cancellation operator; and

performing a soft cancellation of from a received baseband signal to output an interference-cancelled signal.

15. The at least one non-transitory computer-readable medium of claim 14 that includes software that, when executed by the at least one processor, causes further operations comprising:

the generating at least one CIV comprises deriving the estimates from the Rake receiver.

16. The at least one non-transitory computer-readable medium of claim 15, wherein each finger of the Rake receiver is matched to at least one of a time delay or a base station spreading code.

17. The at least one non-transitory computer-readable medium of claim 14 that includes software that, when executed by the at least one processor, causes further operations comprising:

the generating at least one CIV further comprises generating at least one or more soft estimates corresponding to interfering user subchannels from each base station tracked by a cellular handset.

18. The at least one non-transitory computer-readable medium of claim 14, wherein the soft cancellation operator comprises a soft-projection matrix generator or an interference-cancelling operator configured for selecting a soft weight that increases a post-processing signal-to-interference-plus-noise-ratio (SINR).

19. The at least one non-transitory computer-readable medium of claim 14 that includes software that, when executed by the at least one processor, causes further operations comprising:

wherein the generating the at least one CIV comprises deriving the estimates from at least one of a Rake receiver, an equalizer, a receiver employing receive diversity, a receiver employing transmit diversity combining, or a receiver employing space-time decoding.

20. The at least one non-transitory computer-readable medium of claim 14 that includes software that, when executed by the at least one processor, causes further operations comprising:

wherein the performing the soft cancellation further comprises coupling the interference-cancelled signal to at least one of a combiner or a Rake receiver.