72 research outputs found
A Simple Nonlinearity-Tailored Probabilistic Shaping Distribution for Square QAM
A new probabilistic shaping distribution that outperforms Maxwell-Boltzmann
is studied for the nonlinear fiber channel. Additional gains of 0.1 bit/symbol
MI or 0.2 dB SNR for both DP-256QAM and DP-1024QAM are reported after 200 km
nonlinear fiber transmission
LDPC Coded Modulation with Probabilistic Shaping for Optical Fiber Systems
An LDPC coded modulation scheme with probabilistic shaping, optimized
interleavers and noniterative demapping is proposed. Full-field simulations
show an increase in transmission distance by 8% compared to uniformly
distributed input.Comment: 3 pages, 3 figures. Paper is accepted for presentation at OFC 2015.
Following the submission to OFC, the blue box in Fig. 1 has been corrected
and reference [3] has been update
Probabilistically-Shaped Coded Modulation with Hard Decision Decoding for Coherent Optical Systems
We consider probabilistic shaping to maximize the achievable information rate
of coded modulation (CM) with hard decision decoding. The proposed scheme using
binary staircase codes outperforms its uniform CM counterpart by more than 1.3
dB for 64-QAM and 5 bits/symbol
Bit-Metric Decoding of Non-Binary LDPC Codes with Probabilistic Amplitude Shaping
A new approach for combining non-binary low-density parity-check (NB-LDPC)
codes with higher-order modulation and probabilistic amplitude shaping (PAS) is
presented. Instead of symbol-metric decoding (SMD), a bit-metric decoder (BMD)
is used so that matching the field order of the non-binary code to the
constellation size is not needed, which increases the flexibility of the coding
scheme. Information rates, density evolution thresholds and finite-length
simulations show that the flexibility comes at no loss of performance if PAS is
used.Comment: Accepted for IEEE Communication Letter
Sensitivity Gains by Mismatched Probabilistic Shaping for Optical Communication Systems
Probabilistic shaping of quadrature amplitude modulation (QAM) is used to
enhance the sensitivity of an optical communication system. Sensitivity gains
of 0.43 dB and 0.8 dB are demonstrated in back-to-back experiments by shaping
of 16QAM and 64QAM, respectively. Further, numerical simulations are used to
prove the robustness of probabilistic shaping to a mismatch between the
constellation used and the signal-to-noise ratio (SNR) of the channel. It is
found that, accepting a 0.1 dB SNR penalty, only four shaping distributions are
required to support these gains for 64QAM.Comment: Title and introduction were updated and the discussion of Section
IV-B was extended. Additionally, some minor modifications were made to the
manuscrip
Ultra-Sparse Non-Binary LDPC Codes for Probabilistic Amplitude Shaping
This work shows how non-binary low-density parity-check codes over GF()
can be combined with probabilistic amplitude shaping (PAS) (B\"ocherer, et al.,
2015), which combines forward-error correction with non-uniform signaling for
power-efficient communication. Ultra-sparse low-density parity-check codes over
GF(64) and GF(256) gain 0.6 dB in power efficiency over state-of-the-art binary
LDPC codes at a spectral efficiency of 1.5 bits per channel use and a
blocklength of 576 bits. The simulation results are compared to finite length
coding bounds and complemented by density evolution analysis.Comment: Accepted for Globecom 201
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