System and method for low density spreading modulation detection

• US 9,577,703 B2
• Filed: 05/05/2016
• Issued: 02/21/2017
• Est. Priority Date: 12/14/2012
• Status: Active Grant

• Current Assignee: Huawei Technologies Co., Ltd. (Huawei Investment & Holding Co., Ltd.)
• Original Assignee: Huawei Technologies Co., Ltd. (Huawei Investment & Holding Co., Ltd.)
• Inventors: Baligh, Mohammadhadi, Nikopour, Hosein, Bayesteh, Alireza
• Primary Examiner(s): Washburn, Daniel
• Assistant Examiner(s): Tadese, Berhanu
• Application Number:
  US15/147,241
• Publication Number:
  US 20160248472A1
• Time in Patent Office: 292 Days
• Field of Search: 375/150
• US Class Current: 1/1
• CPC Class Codes: H04B 1/707 using direct sequence modulation
• CPC Class Codes: H04B 1/709 Correlator structure
• CPC Class Codes: H04B 1/71052 using decorrelation matrix
• CPC Class Codes: H04J 13/0007 Code type

Abstract

In one embodiment, a method for blindly detecting low density activity includes receiving, by a first node from a second node, a signal and executing a joint message passing algorithm (JMPA) on the signal, where executing the JMPA includes jointly producing a decoded signal and an activity list in accordance with the decoded signal, and calculating a plurality of a priori probabilities in accordance with a plurality of log likelihood ratios (LLRs) corresponding to the signal and a plurality of decoded LLRs.

Claims

1. A method for blindly detecting low density activity, the method comprising:

receiving, by a first node from a second node, a signal; and

executing a joint message passing algorithm (JMPA) on the signal, wherein executing the JMPA includes jointly producing a decoded signal and an activity list in accordance with the decoded signal, and calculating a plurality of a priori probabilities in accordance with a plurality of log likelihood ratios (LLRs) corresponding to the signal and a plurality of decoded LLRs.

2. The method of claim 1, wherein the first node is a user equipment (UE) and the second node is a transmit point.

3. The method of claim 1, wherein the first node is a transmit point and the second node is a UE.

4. The method of claim 1, wherein executing the JMPA further comprises executing the JMPA in accordance with a factor graph.

5. The method of claim 4, wherein an inactive signature is represented by a zero constellation point.

6. The method of claim 1, wherein executing the JMPA further comprises:

executing a message passage algorithm (MPA) to produce the plurality of LLRs;

decoding the plurality of LLRs to obtain the plurality of decoded LLRs; and

executing the MPA in accordance with the signal and the plurality of a priori probabilities.

7. The method of claim 1, wherein executing the JMPA further comprises performing hard detection on the signal.

8. The method of claim 1, wherein executing the JMPA further comprises performing soft detection on the signal.

9. A first node comprising:

a processor; and

a non-transitory computer readable storage medium storing programming for execution by the processor, the programming including instructions to;

receive a signal from a second node, and

execute a joint message passing algorithm (JMPA) on the signal, to jointly produce an activity list in accordance with a decoded signal, and calculate a plurality of a priori probabilities in accordance with a plurality of log likelihood ratios (LLRs) corresponding to the signal and a plurality of decoded LLRs.

10. The first node of claim 9, wherein the first node is a user equipment (UE) and the second node is a transmit point.

11. The first node of claim 9, wherein the first node is a transmit point and the second node is a UE.

12. The first node of claim 9, wherein the instructions to execute the JMPA further comprise instructions to execute the JMPA in accordance with a factor graph.

13. The first node of claim 12, wherein an inactive signature is represented by a zero constellation point.

14. The first node of claim 12, wherein the instructions to execute the JMPA further comprise instructions to:

execute a message passage algorithm (MPA) to produce the plurality of LLRs;

decode the plurality of LLRs to obtain the plurality of decoded LLRs; and

execute the MPA in accordance with the signal and the plurality of a priori probabilities.

15. The first node of claim 12, wherein the instructions to execute the JMPA further comprise instructions to perform hard detection on the signal.

16. The first node of claim 12, wherein the instructions to execute the JMPA further comprise instructions to perform soft detection on the signal.

17. A non-transitory computer readable storage medium storing programming for execution by a processor, the programming including instructions to:

receive a signal from a second node; and

execute a joint message passing algorithm (JMPA) on the signal, to jointly produce an activity list in accordance with a decoded signal, and calculate a plurality of a priori probabilities in accordance with a plurality of log likelihood ratios (LLRs) corresponding to the signal and a plurality of decoded LLRs.

18. The storage medium of claim 17, wherein the instructions to execute the JMPA further comprise instructions to execute the JMPA in accordance with a factor graph.

19. The storage medium of claim 18, wherein an inactive signature is represented by a zero constellation point.

20. The storage medium of claim 17, wherein the instructions to execute the JMPA further comprise instructions to:

execute a message passage algorithm (MPA) to produce the plurality of LLRs;

decode the plurality of LLRs to obtain the plurality of decoded LLRs; and

execute the MPA in accordance with the signal and the plurality of a priori probabilities.