Decision-Feedback Detection Strategy for Nonlinear Frequency-Division Multiplexing S. Civelli, E. Forestieri, and M. Secondini
Nonlinear Fourier Transform in Optical Communications th Florence, February 21 , 2018
Introduction Nonlinear Fourier transform (NFT)-based transmission schemes for optical fibre communications to overcome limitation imposed by nonlinearty ● NFT defines a nonlinear spectrum that evolves trivially and linearly along the optical fibre ● Nonlinear Frequency-Division Multiplexing (NFDM) encodes information on the nonlinear spectrum ●
It is not clear yet whether NFDM can outperform conventional systems Decision-Feedback Detection Strategy for Nonlinear Frequency-Division Multiplexing
Nonlinear inverse synthesis (NIS) Digitally diagonalized and linearized channel Transmitted message
Encoder Nonlinear spectrum
Received message
Detector
BNFT
DAC
Time-domain samples
FNFT
Minimum Euclidean distance detection optimal at low powers
Waveform
Channel
Le et al., Nonlinear inverse synthesis for high spectral efficiency transmission in optical fibers, Optics express 2014
ADC
Burst transmission to ● NFT boundary conditions ● Avoid burst-burst interaction during propagation
Decision-Feedback Detection Strategy for Nonlinear Frequency-Division Multiplexing
Nonlinear inverse synthesis (NIS) Digitally diagonalized and linearized channel Transmitted message
Encoder Nonlinear spectrum
Received message
Detector
BNFT
DAC
Time-domain samples
FNFT
Minimum Euclidean distance detection optimal at low powers
Waveform
Channel
ADC
Burst transmission to ● NFT boundary conditions ● Avoid burst-burst interaction during propagation
Decision-Feedback Detection Strategy for Nonlinear Frequency-Division Multiplexing
Nonlinear inverse synthesis (NIS) Digitally diagonalized and linearized channel
Encoder Nonlinear spectrum
Received message
Detector
BNFT
DAC
Time-domain samples
FNFT
Minimum Euclidean distance detection optimal at low powers
Waveform
35 ADC 30 Q-factor (dB)
Transmitted message
25
Channel
Nb=8 ( =1%) Nb=16 ( =2%) Nb=32 ( =4%) Nb=64 ( =7%) Nb=128 ( =14%) Nb=256 ( =24%) Nb=512 ( =39%) Nb=1024 ( =56%)
simulations (fiber link) simulations (AWGN) theory
Burst transmission to 15 ● NFT boundary conditions 10 ● 5 Avoid burst-burst interaction during propagation 0 -20 -15 -10 -5 0 5 10 20
Civelli et al., IEEE Photon. Technol. Lett. 2017
Decision-Feedback Detection Strategy for Nonlinear Frequency-Division Multiplexing
Power (dBm)
Nonlinear inverse synthesis (NIS) Digitally diagonalized and linearized channel
Encoder Nonlinear spectrum
Received message
Detector
BNFT
DAC
Time-domain samples
FNFT
Minimum Euclidean distance detection optimal at low powers
Waveform
35 ADC 30 Q-factor (dB)
Transmitted message
25
Channel
Nb=8 ( =1%) Nb=16 ( =2%) Nb=32 ( =4%) Nb=64 ( =7%) Nb=128 ( =14%) Nb=256 ( =24%) Nb=512 ( =39%) Nb=1024 ( =56%)
simulations (fiber link) simulations (AWGN) theory
Burst transmission to 15 ● NFT boundary conditions 10 ● 5 Avoid burst-burst interaction during propagation 0 -20 -15 -10 -5 0 5 10 20
Civelli et al., IEEE Photon. Technol. Lett. 2017
Decision-Feedback Detection Strategy for Nonlinear Frequency-Division Multiplexing
Power (dBm)
Alternative detection Digitally diagonalized and linearized channel Transmitted message
Encoder Nonlinear spectrum
Received message
Detector
BNFT
DAC
Time-domain samples
FNFT
Waveform
Channel
ADC
Minimum Euclidean distance detection optimal at low powers
Compare the received signal with all possible received noiseless waveforms
Civelli et al., IEEE Photon. Technol. Lett. 2017
Decision-Feedback Detection Strategy for Nonlinear Frequency-Division Multiplexing
NFT causality property
Decision-Feedback Detection Strategy for Nonlinear Frequency-Division Multiplexing
Decision-Feedback BNFT detection
Decision-Feedback Detection Strategy for Nonlinear Frequency-Division Multiplexing
1.5
Received signal
1
Decision-Feedback BNFT detection Rer(t)
0.5
0 -0.5 -1 -1.5
t0
t3 t4
Time
Decision-Feedback Detection Strategy for Nonlinear Frequency-Division Multiplexing
DF-BNFT performance Nb Nb Nb
Nb Nb Nb
Ps
Decision-Feedback Detection Strategy for Nonlinear Frequency-Division Multiplexing
DF-BNFT suboptimality ●
AWGN channel assumption
●
DF-BNFT detection It does not account for the information received after its time window It is affected by error propagation
Decision-Feedback Detection Strategy for Nonlinear Frequency-Division Multiplexing
Impact of fiber propagation Without phase compensation With phase compensation AWGN channel
Nb
Nb Nb Nb
Ps
Decision-Feedback Detection Strategy for Nonlinear Frequency-Division Multiplexing
Impact of error propagation
Q2 (dB)
15
Nb=128 ( =6%) Nb=256 ( =11%) Nb=512 ( =20%)
Nb=1024 ( =34%) Nb=2048 ( =51%) Nb=4096 ( =67%)
10 5 Actual Error-prop. free
0 -5 -25
-20
-15
-10 Ps
Decision-Feedback Detection Strategy for Nonlinear Frequency-Division Multiplexing
-5
0
Conclusions Novel detection strategy for NFT-based systems: minimize the Euclidean distance in the time domain. ● Performance improvement up to 6.2dB ● Semianalytical approximation and bounds given ● Performance decay remains ●
Future work ● ● ●
Implementation of the optimum detection strategy Computational complexity reduction Extension to dual-polarization case
Decision-Feedback Detection Strategy for Nonlinear Frequency-Division Multiplexing
Thank you for your attention! Stella Civelli
[email protected] arXiv preprint arXiv:1801.05338
Decision-Feedback Detection Strategy for Nonlinear Frequency-Division Multiplexing
Performance Vs rate efficiency 25 20
DF-BNFT NFDM FNFT NFDM
Q2 (dB)
15
EDC DBP
10 continuous transmission
5 0 -5
0
10
20
30
40
50
60
70
Rate efficiency η [%]
Decision-Feedback Detection Strategy for Nonlinear Frequency-Division Multiplexing
80
90
100
BER estimation and bounds Assuming AWGN channel and correct previous decision, the probability of error of a given sequence is and
Decision-Feedback Detection Strategy for Nonlinear Frequency-Division Multiplexing
BER estimation and bounds (a)
Ps
Decision-Feedback Detection Strategy for Nonlinear Frequency-Division Multiplexing
BER estimation and bounds (b)
Ps
Decision-Feedback Detection Strategy for Nonlinear Frequency-Division Multiplexing
BER estimation and bounds
Decision-Feedback Detection Strategy for Nonlinear Frequency-Division Multiplexing