Post equalizer SNR estimation May 2015 doc.: IEEE 802.11-15/0496r1 March 2018 Post equalizer SNR estimation Date: 2018-March-5 Authors: Name Company Address Phone Email Alecsander Eitan Qualcomm eitana@qti.qualcomm.com Assaf Kasher akasher@qti.qualcomm.com Michael Grigat Deutsche Telekom m.grigat@telekom.de Alecsander Eitan (Qualcomm) Edward Au (Marvell Semiconductor)
March 2018 Introduction TDD operation requires to have a “Link Maintenance” feature, which includes various parameters regarding the quality of the received signal at the receiver side. Some of these parameters are Post Equalizer SNR and LDPC statistics. This presentation presents the expected behavior of Hard-Decision EVM as a candidate for Post Equalizer SNR estimation and the correlation to LDPC statistics. Alecsander Eitan (Qualcomm)
What is Hard-Decision EVM ? March 2018 What is Hard-Decision EVM ? Estimation of the Post Equalizer SNR is very simple given that the transmitted symbols are known. Hard-Decision EVM is one of the most simplest methods to estimate the Post Equalizer SNR. The estimation can be done as part of the de-mapping process. Post Equalizer SNR based on re-encoded symbols are more accurate (if the LDPC was successfully decoded) but is more complex and expensive. Post Equalizer SNR and Hard-Decision EVM are supporting a very wide range of SNR values. Hard-Decision EVM requires some correction function to reduce the bias. Alecsander Eitan (Qualcomm)
Post Equalizer SNR - True and HD based March 2018 Post Equalizer SNR - True and HD based Alecsander Eitan (Qualcomm)
Simulation DMG SC MCS: 10,11,12,12.1 (16QAM) March 2018 Simulation DMG SC MCS: 10,11,12,12.1 (16QAM) Per each SNR: 100 frames, 20 FDE blocks Fixed point with analog impairments AWGN channel Vertical bars present 5 and 95 percentiles HD based Post Equalizer SNR correction function not included Alecsander Eitan (Qualcomm)
Post Equalizer SNR - True and HD based March 2018 Post Equalizer SNR - True and HD based Alecsander Eitan (Qualcomm)
Post Equalizer SNR - True and HD based March 2018 Post Equalizer SNR - True and HD based Alecsander Eitan (Qualcomm)
Post Equalizer SNR - True and HD based March 2018 Post Equalizer SNR - True and HD based Alecsander Eitan (Qualcomm)
Post Equalizer SNR - True and HD based March 2018 Post Equalizer SNR - True and HD based QPSK Alecsander Eitan (Qualcomm)
Post Equalizer SNR - True and HD based March 2018 Post Equalizer SNR - True and HD based QPSK Alecsander Eitan (Qualcomm)
Post Equalizer SNR and LDPC average iterations March 2018 Post Equalizer SNR and LDPC average iterations Alecsander Eitan (Qualcomm)
Post Equalizer SNR and LDPC average iterations March 2018 Post Equalizer SNR and LDPC average iterations Alecsander Eitan (Qualcomm)
March 2018 Conclusion The HD based Post Equalizer EVM is a good approximation method for the Post Equalizer EVM. Low variability Wide dynamic range Saturation effect at low SNR – to be compensated by correction function Saturation effect at high SNR caused by quantization Compensation per modulation is required Alecsander Eitan (Qualcomm)