To overcome the severe losses beyond 28 GHz in low-cost electrical channels, 4-level pulse-amplitude modulation (4-PAM) wireline links targeting 112 Gb/s incorporate resource- or power-intensive equalization schemes such as decision-feedback equalizers (DFE) with many taps. Alleviating the timing constraints that cause DFEs to balloon in size and power, discrete multitone (DMT) modulation involves independent sub-channels that can be equalized in the frequency domain without feedback. DMT allows flexibility in assigning bits to each sub-channel, thereby potentially avoiding lossy parts of the frequency spectrum. This article presents behavioural modeling results and an experimental setup used to study DMT transceivers. Our simulations show 200 Gb/s operation at a bit error rate (BER) of less than ${10^{-5}}$ over an IEEE P802.3ck channel with 21 dB of loss at 50 GHz and assuming $150~\mathrm{fs_{rms}}$ of jitter, $1.26~{\mathrm{ mV}}_{\mathrm{ rms}}$ of noise at the receiver’s input, and 7-bit 80 GS/s data converters. An updated bit-loading algorithm led to BER values 1–2 orders of magnitude below our previous results. The estimated power and area of the associated digital signal processing are comparable to those of DFE. We also present an experimental DMT setup achieving 61.6 Gb/s at a BER of ${8.6 \times 10^{-4}}$ over a physical channel with severe notches that is very challenging for 4-PAM.

中文翻译：

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超过100 Gb / s的有线链路的离散多音调制研究

为了克服低成本电气信道中超过28 GHz的严重损耗，针对112 Gb / s的4级脉冲幅度调制（4-PAM）有线链路采用了资源密集型或功率密集型均衡方案，例如决策反馈均衡器（ DFE）。为减轻导致DFE尺寸和功率膨胀的时序约束，离散多音（DMT）调制涉及独立的子信道，这些子信道可以在频域中均衡化而无需反馈。DMT允许灵活地将位分配给每个子信道，从而潜在地避免频谱的有损部分。本文介绍了行为建模结果和用于研究DMT收发器的实验装置。我们的仿真显示，在200 Gb / s的操作下，误码率（BER）小于 $ {10 ^ {-5}} $ 通过IEEE P802.3ck信道在50 GHz时损耗为21 dB，并假设 $ 150〜\ mathrm {fs_ {rms}} $ 抖动 $ 1.26〜{\ mathrm {mV}} _ {\ mathrm {rms}} $ 接收器输入端的噪声以及7位80 GS / s数据转换器的噪声。更新的位加载算法导致BER值比我们以前的结果低1-2个数量级。相关数字信号处理的估计功率和面积与DFE相当。我们还介绍了一种实验性DMT设置，在BER达到61.6 Gb / s的情况下 $ {8.6 \ times 10 ^ {-4}} $ 在具有严重陷波的物理通道上传输，这对于4-PAM来说是非常困难的。