System and method for low density spreading modulation detection
View Patent ↗In one embodiment, a method for blindly detecting low density spreading (LDS) active signatures including receiving, by a first node from a second node, a signal and decorrelating the signal in accordance with a signature list to obtain an active signature list. The method also includes decoding the signal in accordance with the active signature list to obtain a decoded signal.
1. A method for blindly detecting low density spreading (LDS) active signatures, 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 active signature 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 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 active signature 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 9 , 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 9 , wherein the instructions to execute the JMPA further comprise instructions to perform hard detection on the signal.
16. The first node of claim 9 , wherein the instructions to execute the JMPA further comprise instructions to perform soft detection on the signal.