Detector for single-user coded signals in the presence of interference
View Patent ↗Techniques are provided for detecting a coded signal in the presence of interference. In an embodiment, a primary transmitter corresponds to a desired transmitter, and one or more secondary transmitters correspond to interfering transmitters. Received symbols, which include interference and additive noise, are filtered to recover a set of original message bits. An estimate of the set of original message bits may be determined using an ordered successive interference cancellation (SIC) decoder that uses either a SIC detector or an AWGN-based detector, depending on the signal-to-interference ratio at a primary receiver.
1. A method of decoding symbols, the method comprising:
receiving a symbol comprising a data portion, an interference portion, and a noise portion;
determining a signal constellation for the symbol based on a first signal constellation associated with the data portion and a second signal constellation associated with the interference portion;
decoding the interference portion based on a distance metric between the symbol and the data portion;
removing the decoded interference portion from the symbol to produce a modified symbol; and
decoding the data portion based on the modified symbol.
2. The method of claim 1 , wherein the signal constellation for the symbol is a composition of the first signal constellation and the second signal constellation.
3. The method of claim 1 , wherein the distance metric is a Euclidean distance.
4. The method of claim 1 , wherein the first signal constellation and the second signal constellation correspond to the same modulation type.
5. The method of claim 1 , wherein the data portion is transmitted by a primary transmitter and the interference portion is transmitted by one or more secondary transmitters.
6. The method of claim 1 , further comprising decoding the data portion using a successive interference cancellation (SIC) detector.
7. The method of claim 1 , wherein the first signal constellation and the second signal constellation are each non-Gaussian.
8. The method of claim 1 , wherein the first signal constellation is Binary Phase Shift Keying (BPSK).
9. The method of claim 1 , wherein removing the decoded interference portion from the symbol portion to produce a modified symbol comprises subtracting the decoded interference portion from the symbol portion.
10. The method of claim 5 , wherein the primary transmitter and the one or more secondary transmitters transmit data asynchronously.
11. A system comprising:
receiver circuitry configured to receive a symbol comprising a data portion, an interference portion, and a noise portion; and
decoding circuitry configured to:
determine a signal constellation for the symbol based on a first signal constellation associated with the data portion and a second signal constellation associated with the interference portion;
decode the interference portion based on a distance metric between the symbol and the data portion;
remove the decoded interference portion from the symbol to produce a modified symbol; and
decode the data portion based on the modified symbol.
12. The system of claim 11 , wherein the signal constellation for the symbol is a composition of the first signal constellation and the second signal constellation.
13. The system of claim 11 , wherein the distance metric is a Euclidean distance.
14. The system of claim 11 , wherein the first signal constellation and the second signal constellation are of a common modulation type.
15. The system of claim 11 , wherein the data portion is transmitted by a primary transmitter and the interference portion is transmitted by one or more secondary transmitters.
16. The system of claim 11 , wherein the decoding circuitry is further configured to decode the data portion using a successive interference cancellation (SIC) detector.
17. The system of claim 11 , wherein the first signal constellation and the second signal constellation are each non-Gaussian.
18. The system of claim 11 , wherein the first signal constellation is Binary Phase Shift Keying (BPSK).
19. The system of claim 11 , wherein the decoding circuitry is further configured to remove the decoded interference portion from the symbol portion to produce a modified symbol by subtracting the decoded interference portion from the symbol portion.
20. The system of claim 15 , wherein the primary transmitter and the one or more secondary transmitters transmit data asynchronously.