Eye modulation for pulse-amplitude modulation communication systems
View Patent ↗The present invention is directed to communication systems. More specifically, embodiments of the present invention provide a technique and system thereof for performing eye modulation. Eye modulation is performed at the transmission side of a PAM communication system to compensate for distortion and non-linearity and generate an output waveform. Spacing among eye levels is adjusted by performing symmetric modulation using α parameter and asymmetric modulation using β parameter. A correction module measures the output waveform and sends feedback signals to a control module to adjust the α parameter and the β parameter. There are other embodiments as well.
1. A method for performing pulse-amplitude modulation, the method comprising:
determining distortion information associated with a data path by a receiving module;
receiving the distortion information from the receiving module to the transmitting module;
calculating a α parameter based on the distortion information, the α parameter being associated with a symmetrical eye level adjustment;
calculating a β parameter based on the distortion information, the β parameter being associated with an asymmetrical eye level adjustment;
performing eye-modulation on an outgoing data stream using at least a predetermined formula, the predetermined formula applying both the α parameter and the β parameter; and
transmitting the modulated outgoing data stream.
2. The method of claim 1 further comprising adjusting a middle eye height using at least the α parameter.
3. The method of claim 1 further comprising adjusting a top eye height using at least the β parameter.
4. The method of claim 3 further comprising adjusting a bottom eye height using at least the β parameter.
5. The method of claim 1 further comprising determining an SNR information associated with the data path.
6. The method of claim 1 further comprising:
measuring an updated distortion information associated with the modulated outgoing data stream;
updating the α parameter based on the updated distortion information.
7. The method of claim 1 further comprising transmitting the outgoing data stream using a PAM transmitter.
8. The method of claim 1 wherein the outgoing data stream comprises PAM4 signals.
9. The method of claim 1 further comprising calculating compensation coefficients using the α parameter and the β parameter.
10. The method of claim 9 further comprising calculating the compensation coefficients using a plurality of predetermined formulae.
11. The method of claim 1 further comprising adjusting MSB data of the outgoing data stream using the α parameter.
12. The method of claim 1 further comprising adjusting LSB data of the outgoing data stream using the α parameter.
13. A method for performing pulse-amplitude modulation, the method comprising:
receiving a first data stream;
determining one or more SNR values associated with a data path by a receiving entity;
receiving the SNR values;
calculating a α parameter based on the SNR values, the α parameter being associated with a middle eye height;
calculating a β parameter based on the SNR values, the β parameter being associated with a top eye height;
performing eye modulation on a second data stream;
compensating eye levels of the second data stream using at least the α parameter and the β parameter; and
transmitting the modulated second data stream.
14. The method of claim 13 wherein the second data stream comprises MSB data and LSB data, a function of the MSB data XOR the LSB data being modified by the β parameter.
15. The method of claim 13 wherein the β parameter is further associated with a bottom eye height.
16. The method of claim 13 wherein the eye levels comprise a top level and a bottom level, the top level being characterized by a greater height than the bottom level.
17. The method of claim 13 further comprising adjusting the α parameter and the β parameter until the eye levels of a third data stream received by the receiving entity are substantially equal.
18. A method for performing pulse-amplitude modulation, the method comprising:
receiving a first set of SNR values associated with a first data stream from a receiving entity;
calculating a α parameter based on the SNR values, the α parameter being associated with a middle eye height;
calculating a β parameter based on the SNR values, the β parameter being associated with a top eye height;
performing eye modulation on a second data stream by a transmitting entity;
compensating eye levels of the second data stream using at least the α parameter and the β parameter;
transmitting the modulated data stream;
receiving the second set of SNR values associated with the second data stream the receiving entity; and
adjusting the α parameter and the β parameter based on the second set of SNR values by the transmitting entity.
19. The method of claim 18 further comprising calculating compensation coefficients by applying the α parameter and the β parameter to a plurality of formulae.