Phase-noise mitigation by embedded phase-tracking signals in 5G/6G
View Patent ↗Access to FR2 (high frequency bands) is essential for anticipated high-demand networking in 5G-Advanced and 6G systems. Unfortunately, phase noise is an unavoidable barrier, greatly limiting message reliability. Therefore, a low-cost solution is provided in which the transmitter (either base station or user device) transmits a special phase-tracking reference signal consisting of zero amplitude in one branch, and a predetermined non-zero amplitude in the other branch. For example, in QAM, the I-branch may be powered according to the maximum branch amplitude of the modulation scheme, and the Q-branch may have zero amplitude as transmitted. The receiver, on the other hand, generally measures a non-zero amplitude in the received Q branch due to phase noise, which rotates the I and Q branches into each other. The receiver can then determine the phase rotation angle precisely by measuring the non-zero amplitude in the Q branch, negating phase noise at negligible cost.
1. A method for a wireless transmitter to communicate with a wireless receiver, the method comprising:
a) transmitting a modulated resource element comprising an I-branch multiplexed with an orthogonal Q-branch, the I-branch amplitude modulated according to a predetermined non-zero amplitude, and the Q-branch transmitted with zero amplitude.
2. The method of claim 1 , wherein the resource element is configured according to 5G or 6G technology.
3. The method of claim 1 , wherein the predetermined non-zero amplitude comprises a maximum branch amplitude of the modulation scheme.
4. The method of claim 1 , wherein the predetermined non-zero amplitude comprises a V2 times a maximum branch amplitude of the modulation scheme.
5. The method of claim 1 , wherein the modulated resource element comprises a first resource element in a message.
6. The method of claim 1 , wherein the modulated resource element is embedded within a message.
7. The method of claim 1 , wherein the modulated resource element comprises a last resource element in a message.
8. The method of claim 1 , wherein the modulated resource element occupies a predetermined subcarrier and a predetermined symbol-time in a resource grid.
9. A method for a wireless receiver to communicate with a wireless transmitter, the method comprising:
a) receiving a modulated resource element comprising an I-branch multiplexed with an orthogonal Q-branch, the I-branch amplitude modulated according to a predetermined non-zero amplitude, and the Q-branch transmitted with zero amplitude.
10. The method of claim 9 , wherein the predetermined non-zero amplitude comprises a maximum branch amplitude of the modulation scheme.
11. The method of claim 9 , wherein the predetermined non-zero amplitude comprises a √2 times a maximum branch amplitude of the modulation scheme.
12. The method of claim 9 , wherein the modulated resource element comprises a first resource element in a message.
13. The method of claim 9 , wherein the modulated resource element is embedded within a message.
14. The method of claim 9 , wherein the modulated resource element comprises a last resource element in a message.
15. A method for a first wireless entity to communicate with a second wireless entity, the method comprising:
a) transmitting a modulated resource element modulated according to a modulation scheme comprising an amplitude-modulated I branch multiplexed with an orthogonal amplitude-modulated Q branch;
b) wherein one branch, of the I and Q branches, is transmitted with a predetermined non-zero amplitude, and the other branch has zero amplitude, as transmitted.
16. The method of claim 15 , wherein the predetermined non-zero amplitude comprises a maximum branch amplitude of the modulation scheme.
17. The method of claim 15 , wherein the predetermined non-zero amplitude comprises a √2 times a maximum branch amplitude of the modulation scheme.
18. The method of claim 15 , wherein the modulated resource element comprises a first resource element in a message.
19. The method of claim 15 , wherein the modulated resource element is embedded within a message.
20. The method of claim 15 , wherein the modulated resource element comprises a last resource element in a message.