Signal Processing for Gigabit-Rate Wireline Communications: An Overview of the State of the Art and Research Challenges

Zafaruddin, S. M.; Bergel, Itsik; Leshem, Amir

doi:10.1109/msp.2017.2712824

Cited by 20 publications

(22 citation statements)

References 61 publications

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“…Finally, note that a limit of this type is also used in the DMT systems employed in DSL applications. However, given the lower data rates and better SNR conditions in such applications, modulation orders up to 12 (hence, 4096-QAM) are allowable in some DSL standards [27], while others set an even higher limit on the constellation sizes.…”

Section: Bit-loadingmentioning

confidence: 99%

A Study of Discrete Multitone Modulation for Wireline Links Beyond 100 Gb/s

Vatankhahghadim

Wary

Bailey

et al. 2021

IEEE Open J. Circuits Syst.

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To overcome the severe losses beyond 28 GHz in low-cost electrical channels, 4-level pulseamplitude 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 fs rms of jitter, 1.26 mV 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 × 10 −4 over a physical channel with severe notches that is very challenging for 4-PAM. INDEX TERMS Digital modulation, digital signal processing (DSP), discrete multitone (DMT), transceivers, wireline communication.

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Section: Bit-loadingmentioning

confidence: 99%

A Study of Discrete Multitone Modulation for Wireline Links Beyond 100 Gb/s

Vatankhahghadim

Wary

Bailey

et al. 2021

IEEE Open J. Circuits Syst.

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“…This is once again due to the high reliability of URLLC transmission. It is in fact easy to prove that for ρ = 1 and low values of D U , the SIC eMBB rate in (42) converges to the one of TIN in (39).…”

Section: Numerical Resultsmentioning

confidence: 93%

“…However, this would require the use of more complex precoding techniques, such as Tomlinson-Harashima [37], which require an estimate of the fronthaul channel. Since for wired fronthauling the channel is nearly static and time-invariant, channel state information can be easily obtained [42]). For µ = 1/4 instead, disjoint portions of the radio signal are transmitted over different interfering twisted-pairs, and the performance progressively decrease with γ 2 .…”

Section: Numerical Resultsmentioning

confidence: 99%

Non-Orthogonal eMBB-URLLC Radio Access for Cloud Radio Access Networks with Analog Fronthauling

Matera

Kassab

Simeone

et al. 2018

Entropy

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This paper considers the coexistence of Ultra Reliable Low Latency Communications (URLLC) and enhanced Mobile BroadBand (eMBB) services in the uplink of Cloud Radio Access Network (C-RAN) architecture based on the relaying of radio signals over analog fronthaul links. While Orthogonal Multiple Access (OMA) to the radio resources enables the isolation and the separate design of different 5G services, Non-Orthogonal Multiple Access (NOMA) can enhance the system performance by sharing wireless and fronthaul resources. This paper provides an information-theoretic perspective in the performance of URLLC and eMBB traffic under both OMA and NOMA. The analysis focuses on standard cellular models with additive Gaussian noise links and a finite inter-cell interference span, and it accounts for different decoding strategies such as puncturing, Treating Interference as Noise (TIN) and Successive Interference Cancellation (SIC). Numerical results demonstrate that, for the considered analog fronthauling C-RAN architecture, NOMA achieves higher eMBB rates with respect to OMA, while guaranteeing reliable low-rate URLLC communication with minimal access latency. Moreover, NOMA under SIC is seen to achieve the best performance, while, unlike the case with digital capacity-constrained fronthaul links, TIN always outperforms puncturing.

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“…As shown in Eq. (19), the detection SNR required by the QAM demappers is related to the gain of the (rotated) direct channel r k,k . Because of the DFE nature of the THP, the magnitude of r k,k and thus the detection SNR usually degrades with the user's index k during transmit precoding.…”

Section: ) Sorted Thpmentioning

confidence: 99%

“…13. The remaining components are structured similarly in both cases, except for the extra direct channel equalizers (1/r k,k ) required for a ZF-THP based receiver as formulated in (19). Since matrix filters can be implemented efficiently with the advent of parallel computing, whereas the decision feedback loop cannot, the LR-ZFP based transmitter would incur a lower processing delay than the ZF-THP based transmitter.…”

Section: ) Lr-zfpmentioning

confidence: 99%

Far-End Crosstalk Mitigation for Future Wireline Networks Beyond G.mgfast: A Survey and an Outlook

Zhang

et al. 2020

IEEE Access

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With the escalating demand for high speed, high reliability, low latency, low cost and ubiquitous connectivity, the telecommunications industry is entering a new era where the ultimate optimality of the current wireline-wireless access network has to be achieved. Regarding the current wireline network paradigm, dominated by the copper-based digital subscriber lines (DSL) technology, multi-Gigabit data rate is the ambitious design objective at the customer end for the forthcoming ITU-T G.mgfast standard. In order to prepare for the new challenges in the era of total network convergence, both the wireline and the wireless community must be able to think beyond their respective conventions and learn from each other if necessary. Overall, the current DSL-based wireline network architecture is prone to the mutual interference resulting in far-end crosstalk (FEXT). The newly expanded 424/848 MHz spectrum of the ambitious G.mgfast project introduces far higher FEXT than that over the current 212/30 MHz G.fast/VDSL2 band. Additionally, the coexistence of multiple standards will also cause 'alien' FEXT. In these cases, using the plain zero forcing precoding (ZFP) will no longer attain a sufficiently high performance. However, as shown in the field of wireless communications, using lattice reduction as a signal space remapping technique significantly improves the performance of traditional multiuser detectors (MUD) and of the respective multiuser precoders (MUP). These promising techniques have largely remained unexploited in commercial wireless communications, due to their complexity in the face of the rapidly fluctuating wireless channels. In this survey, we present an overview of the state-of-the-art in wireline access network and an outlook for recent technological advances in the holistic 'wireline + wireless' access network in the context of network convergence, focusing on the dominant challenge of FEXT mitigation in future DSL networks. Against this background, we investigate both the family of linear precoding and of the Tomlinson-Harashima precoding (THP) schemes conceived for classic DSL. Furthermore, we present a tutorial on the family of lattice reduction aided MUPs, as well as quantifying their expected performances in realistic DSL scenarios. As a by-product, we also demonstrate the duality between MUP and MUD, in the hope that the fifty years' history of MUD could be used to accelerate the development of efficient near-optimal MUPs for future DSL. Under the recommended operating conditions of the 212 MHz profile of G.fast, our benchmark comparisons indicate that the lattice reduction aided techniques are very powerful compared to conventional schemes. In particular, their good performances do not rely on optimized spectrum balancing, and they are also shown to be relatively robust against channel state information (CSI) estimation error, under the assumption of perfectly time-invariant DSL channels.

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Signal Processing for Gigabit-Rate Wireline Communications: An Overview of the State of the Art and Research Challenges

Cited by 20 publications

References 61 publications

A Study of Discrete Multitone Modulation for Wireline Links Beyond 100 Gb/s

A Study of Discrete Multitone Modulation for Wireline Links Beyond 100 Gb/s

Non-Orthogonal eMBB-URLLC Radio Access for Cloud Radio Access Networks with Analog Fronthauling

Far-End Crosstalk Mitigation for Future Wireline Networks Beyond G.mgfast: A Survey and an Outlook

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