Next-generation Broadband Research Articles

COVID-19 and Us!

As a world leading scholarly and scientific publication, the IEEE Communications Magazine calls upon our global community - in and beyond the IEEE Communications Society - to actively participate in the COVID-19 battle. While we distance our bodies from each other to prevent infection we have to bring our minds closer together to develop novel technologies and solutions to help win this battle, restore our normal life, and better prepare for future challenges. Areas such as e-Health; telemedicine; technology and health; robotics; safe/smart packaging; smart cities; agile connectivity; next-generation broadband; cybersecurity; data and network analytics; artificial intelligence; virtual, augmented, and mixed reality; and online learning and education are just a few examples of topics in need of innovative research, invention, and progression. This work is desperately needed to face today’s situation and prepare for future ones. We ask our authors, readers, and all our community professionals to contribute their ideas and research in these areas and others by authoring papers and proposing feature topics thereto.

Implementing policy on next-generation broadband networks and implications for equity of access to high speed broadband: A case study of Australia's NBN

Next generation telecommunications infrastructure is expanding and supporting rapid growth of broadband technologies and a digital economy. In this context, digital information and communications technologies (ICTs) are of increasing importance as a means for people to gain access to health or social services, employment opportunities, information and social networks. In this article we draw on our recent case study research to examine the policy (and politics) shaping implementation of Australia's National Broadband Network (NBN) and its likely effects on equity of access to high speed broadband (HSB) services. We monitored NBN policy and implementation from 2015 to 2018 through policy documents, reports, and media. To assess likely effects of NBN policy on implementation and subsequently on equity of access to HSB we: a) applied a framework defining four elements of equity of access; and b) analysed stakeholder views drawn from media articles and 22 interviews with experts on NBN policy including politicians, government staff, and industry representatives. We found that equity considerations competed with political and commercial imperatives during the rollout of the NBN. This resulted in positive and negative consequences for equity of access to HSB, with a change in policy and implementation in 2013 bringing greater risks to equity of access. The case study provides a framework for considering equity in the implementation of next generation telecommunications infrastructure and highlights the importance of considering equity in the evaluation of telecommunications infrastructure.

Getting some reality into debates about NBN FTTP

Sentiment about fibre-to-the-premises (FTTP) runs hot in Australia, fuelled by the NBN initiative for Australia's next generation of broadband. Unfortunately most of the debate is ill-informed, focusing on plumbing rather than the uses to which the network may be put. The base of users subscribing to the higher speeds made possible by FTTP is limited right now, and much of their communication will be speed-limited by constraints outside of the NBN FTTP segment. In addition, a growing proportion of Australians choose to operate entirely on mobile connections. For all these reasons, the number of users who would benefit from FTTP in the short term is modest.
 The Coalition has proposed greater use of existing infrastructure – in particular, using fibre-to-the-node (FTTN)/DSL technology and potentially hybrid-fibre-coax (HFC) technology – to deliver an upgrade earlier and at lower cost. In the face of cost pressures, it is likely that the original 93% FTTP target would be adjusted with greater use of wireless and satellite technologies in rural areas and the use of copper for the final link in multi-dwelling complexes. More generally, there is no question that FTTN/DSL solutions can deliver good quality broadband, but further work will be needed to determine where this can be done cost-effectively. Similarly, with appropriate upgrades, HFC networks can deliver next-generation broadband speeds. When practical factors are taken into consideration, the gap between Labor and Coalition plans closes somewhat.
 Developing the best strategy for Australia needs to take cost into consideration, and there is scope for NBN Co to improve its performance in this area. Any major cost blowout would have significant ramifications for broadband users and use in Australia. If the rollout of FTTP is scaled back, users with a need may still get access on a user-pays principle – though the practicality of this has yet to be demonstrated. Widespread FTTP remains the right long-term goal for Australia, but the approach for getting there needs to be finessed.

Enhanced Broadband Responsivity of Ni-Doped Sb2Se3 Nanorod Photodetector

Antimony selenide (Sb2Se3) semiconductor with a narrow band gap is regarded as an ideal candidate for the next-generation broadband photodetectors. However, the photodetectors based on the binary S...

Low-Latency Oriented Network Planning for MEC-Enabled WDM-PON Based Fiber-Wireless Access Networks

WDM-PON-based mobile edge computing (MEC)-enabled fiber wireless access networks (MFWAN) have been identified as a promising technology for next-generation broadband access. Low-latency oriented network planning of the WDM-PON-based MFWAN would be required for low-latency access to newly emerging latency-sensitive applications in the fifth-generation (5G) era. However, this would require a low-latency oriented network design in the network planning phase and has thus become a crucial challenge. In this paper, we investigate low-latency oriented network planning of the WDM-PON-based MFWAN under physical and management constraints. To this end, we develop a mathematical model to minimize total transmission latency for all latency-sensitive services. Our model is composed of the propagation latency on the paths and the processing latency on the network equipment and is subject to constraints of maximal transmission distance, maximal PON power budget, bandwidth requests, and the fronthaul latency limit under some functional split options. Given the model’s complexity, we also propose a heuristic algorithm called latency-minimized integrated multi-associated positioning and routing algorithm (LMI-MAPRA). The simulation results show that the proposed algorithm outperforms the benchmark algorithm with more total transmission latency reductions in both sparse and dense networks. We also analyze the impact of key parameters on comparisons of different approaches in terms of low-latency optimal performances.

Deep Learning-Based Dynamic Bandwidth Allocation for Future Optical Access Networks

Over the last decade, Passive Optical Networks (PONs) have emerged as an ideal candidate for next-generation broadband access networks. Meanwhile, machine learning and more specifically deep learning has been regarded as a star technology for solving complex classification and prediction problems. Recent advances in hardware and cloud technologies offer all the necessary capabilities for employing deep learning to enhance Next-Generation Ethernet PON’s (NG-EPON) performance. In NG-EPON systems, control messages are exchanged in every cycle between the optical line terminal and optical network units to enable dynamic bandwidth allocation (DBA) in the upstream direction. In this paper, we propose a novel DBA approach that employs deep learning to predict the bandwidth demand of end-users so that the control overhead due to the request-grant mechanism in NG-EPON is reduced, thereby increasing the bandwidth utilization. The extensive simulations highlight the merits of the new DBA approach and offer insights for this new line of research.

Bandwidth Allocation and Control Message Scheduling Algorithms for Improving the QoSs of High Priority Traffic in PON

The passive optical network (PON) is the most promising candidate for supporting multiple service classes, i.e., high priority (HP) traffic and best-effort (BE) traffic, in the next-generation broadband access networks. Providing an efficient dynamic bandwidth allocation (DBA) algorithm is the most important issue for supporting multiple service classes of traffic simultaneously. This paper presents a new DBA algorithm, which is the modified version of the hybrid slot-size/rate (HSSR) scheme, and is called the modified HSSR (MHSSR) algorithm. We have also modified the control message scheduling algorithm to fit it to the proposed scheme. In the proposed MHSSR scheme, each cycle time, i.e., the length of a time cycle, is equally divided into two parts. In the 1st part of the cycle time, the bandwidth is dynamically allocated to the HP traffic of all the optical network units (ONUs). In contrast, in the 2nd part of the cycle time, the bandwidth is dynamically allocated to the BE traffic of one or multiple ONUs. Furthermore, to ensure guaranteed service for the HP traffic, the 1st part of the cycle time is extended while the 2nd part of the cycle time is compressed if the demand of the HP traffic is very high. However, the 1st part of the cycle time will never be compressed, even at the lightly loaded condition of the HP traffic. The modified control message-scheduling algorithm effectively coordinates the timing sequence between the two parts of the cycle time and ensures the synchronization between two Gate messages to each ONU. We have evaluated the performance of the proposed schemes through numerical simulations in terms of end-to-end packet delay, bandwidth wastage, remaining bytes per time cycle, jitter, and throughput for different offered loads. From the comparative analysis, it can be seen that the proposed scheme provides better performance than the existing HSSR and delay variation-guaranteed schemes.

Broadband Terahertz Generation via the Interface Inverse Rashba-Edelstein Effect.

Novel mechanisms for electromagnetic wave emission in the terahertz frequency regime emerging at the nanometer scale have recently attracted intense attention for the purpose of searching next-generation broadband THz emitters. Here, we report broadband THz emission, utilizing the interface inverse Rashba-Edelstein effect. By engineering the symmetry of the Ag/Bi Rashba interface, we demonstrate a controllable THz radiation (∼0.1-5 THz) waveform emitted from metallic Fe/Ag/Bi heterostructures following photoexcitation. We further reveal that this type of THz radiation can be selectively superimposed on the emission discovered recently due to the inverse spin Hall effect, yielding a unique film thickness dependent emission pattern. Our results thus offer new opportunities for versatile broadband THz radiation using the interface quantum effects.

Hybrid Fiber-Wireless Network: An Optimization Framework for Survivable Deployment

Abstract—Hybrid fiber-wireless (FiWi) networks, which benefit from high bandwidth and ubiquitous access of optical and wireless networks, have been identified as a promising technology candidate for next-generation broadband access. As various component/fiber failures may occur in hybrid FiWi networks, thus affecting huge numbers of end users, survivability has become one of the key important deployment considerations in such networks. This paper focuses on developing optimal network planning strategies to achieve survivable hybrid FiWi networks. In particular, to address the additional cost involved in deploying backup fibers in previously proposed redundancy strategies against distribution fiber failures, we propose the use of wireless routing through the ubiquitous wireless coverage of end users in a hybrid FiWi network. We present an optimization framework to optimally plan and deploy a survivable hybrid FiWi network, where traffic from an affected optical network unit (ONU) can be effectively rerouted to backup ONUs through wireless connections in the event of a distribution fiber failure. However, focusing only on the resilience of a network without considering its cost, and ignoring the resultant capacity, latency, and coverage under normal and protection operating conditions, is impractical. Our proposed framework therefore ensures maximum end-user coverage whilst satisfying survivability, connectivity, delay, and capacity constraints of the network, by optimizing the placement of passive optical splitters, ONUs, and wireless routers in conjunction with fiber and wireless connections. Moreover, we demonstrate the feasibility of our framework in the context of an urban deployment under different deployment scenarios. In particular, our results provide insight into how survivable FiWi networks can be deployed without compromising on the latency, coverage, and capacity requirements of such networks.

Heterogeneous Integration [From the Guest Editors' Desk

Today, there is ever-increasing interest in employing unused electromagnetic spectra and taking advantage of millimeter-wave (mmW) and submillimeter-wave (submmW) or terahertz (THz) frequencies. Current, rapid advances in semiconductor and packaging technologies along with the commercial availability of test equipment up to 1 THz have enabled many important developments at these high-frequency bands. As a result, next-generation broadband and ultrahigh-speed wireless communication systems, high-resolution imagers and sensors, and automotive radars will operate at mmW and sub-mmW regions, which will demand increasingly complex functionalities with better performance, compactness, efficiency, and reliability at a low cost. For semiconductor technologies, silicon (Si) is the dominant material in terms of circuit functionality, complex integration, maturity and yield, and cost. Further, recently integrated Si RF technologies—complementary–metal-oxide semiconductor (CMOS) and bipolar junction transistor/CMOS (BiCMOS)—have made tremendous progress in power, while frequencies have been extended to around 100 GHz. However, there are still applications that can be fulfilled only by compound semiconductor (CS) technology, such as indium phosphide (InP), which provides transistors with fmax of 1 THz, high gain and power, and mixed signal circuits with ultrahigh speed, and gallium nitride (GaN), which enables devices with wide bandwidth, high breakdown voltage, and output power up to 100 GHz. Therefore, integration of dissimilar semiconductors.

Social networks, technology ties, and gatekeeper functionality: Implications for the performance management of R&D projects

R&D project teams concerned with efficiency under limited resources must cohesively coordinate cooperation, interactions, and the exchange of ideas to sustain innovation. This research investigated the management of social networks, technology ties, and gatekeeper functionality from a networking perspective and examined their contribution to R&D performance, which was evaluated using data envelopment analysis. This study verified the relationships by using data from the Taiwan National Telecommunication Program, which coordinates more than 100 R&D teams in pursuing next-generation broadband technologies. The results regarding these relationships varied. The density of social networking and the outward- and novel-oriented gatekeeper functionality of a project team was found to significantly promote its R&D performance, whereas the density of technology ties exhibits no significance. Accordingly, this paper presents strategic implications for the management of projects, team interorganizational linkages, and governmental subsidy policies, and discusses the networking activities of R&D teams at the project level.

Impairment Analysis of WDM-PON Based on Low-Cost Tunable Lasers

WDM-PON is considered for next-generation broadband backhaul and radio access networking. Among different implementation choices, we propose to utilize low-cost tunable lasers at the remote sites, together with a centralized wavelength locker. Practical implementations require a transparently added downstream signaling channel and upstream per-channel pilot tones for channel tagging and remote wavelength control. Together with some unavoidable crosstalk effects during tuning, all of these system-related items lead to impairments. To keep penalties below 1 dB, the modulation index of the signaling channel must be kept below 15%. Similar values result for the upstream pilot tones. In order to limit crosstalk, such systems require reduced launch power during wavelength tuning and can cover up to 40 km differential reach. These results confirm that WDM-PON based on low-cost lasers is a technically viable approach.

Ligand-Driven and Full-Color-Tunable Fiber Source: Toward Next-Generation Clinic Fiber-Endoscope Tomography with Cellular Resolution.

In many biomedical applications, broad full-color emission is important, especially for wavelengths below 450 nm, which are difficult to cover via supercontinuum generation. Single-crystalline-core sapphires with defect-driven emissions have potential roles in the development of next-generation broadband light sources because their defect centers demonstrate multiple emission bands with tailored ligand fields. However, the inability to realize high quantum yields with high crystallinity by conventional methods hinders the applicability of ultra-broadband emissions. Here, we present how an effective one-step fiber-drawing process, followed by a simple and controllable thermal treatment, enables a low-loss, full-color, and crystal fiber-based generation with substantial color variability. The broad spectrum extends from 330 nm, which is over 50 nm further into the UV region than that in previously reported results. The predicted submicrometer spatial resolutions demonstrate that the defect–ligand fields are potentially beneficial for achieving in vivo cellular tomography. It is also noteworthy that the efficiency of the milliwatt-level full-color generation, with an optical-to-optical efficiency of nearly 5%, is the highest among that of the existing active waveguide schemes. In addition, direct evidence from high-resolution transmission electron microscopy together with electron energy loss spectroscopy and crystal-field ligands reveals an excellent crystalline core, atomically defined core/cladding interfacial roughness, and significant enhancements in new laser-induced electronic defect levels. Our work suggests an inexpensive, facile, and highly scalable route toward achieving cellular-resolution tomographic imaging and represents an important step in the development of endoscope-compatible diagnostic devices.

Channel-, Queue-, and Delay-Aware Resource Allocation in Buffer-Aided Relay-Enhanced OFDMA Networks

Resource allocation is an important factor in providing different varieties of services in next-generation broadband wireless systems. In this paper, we consider dynamic routing and subchannel allocation for providing quality of service (QoS) in the downlink of orthogonal frequency-division multiple-access (OFDMA) networks enhanced with buffering relays. Specifically, we consider satisfying the QoS requirements of both delay-sensitive users with the goal of meeting packet deadline constraints and delay-tolerant users who need guarantees on their average throughputs. We provide a framework for “time-domain scheduling” and “frequency-domain resource allocation,” and based on this, we propose novel channel-, queue-, and delay-aware policies for formulating and solving the joint routing and resource allocation problem. In particular, these policies take different approaches to decide on the set of users considered in the utility function, the delay budget division between the base station and relays, the routing path of delay-sensitive users' packets, and the computation of minimum rate requirements for serving their queues. We present an iterative algorithm to solve the resulting problems. Numerical results show significant improvements in throughput and delay performance of the proposed resource allocation mechanisms compared with existing algorithms.

Wavelength division multiplexing passive optical networks (WDM PONs) With Downstream DPSK and Upstream Remodulated OOK using Injection-Locked Fabry-Perot Laser Diodes (FP-LDs)

Wavelength Division Multiplexing-Passive Optical Network (WDM-PON) system based on the injection locked Fabry-Perot laser diode (FP-LD) has been investigated. The system has been demonstrated without dispersion compensation for both 10Gbps Differential phase-shift keying (DPSK) downstream signal and 2.5Gbps On-off keying (OOK) upstream signal respectively. Error free transmission over 50-km is achieved by tailoring the parameters of the FP-LD. The BER performance of our system shows that the injection locked FP-LD is a low cost effective colourless transmitter for high-speed WDM-PONs. Full Text: PDF References E. Wong, "Next-Generation Broadband Access Networks and Technologies", J. Lightwave Technol. 30(4), 597 (2012). CrossRef F.T. An, D. Gutierrez, K.S. Kim, J.W. Lee, L.G. Kazovsky, "SUCCESS-HPON: A next-generation optical access architecture for smooth migration from TDM-PON to WDM-PON", IEEE Commun. Mag. 43(11), S40 (2005). CrossRef S.-J. Park, C.-H. Lee, K.-T. Jeong, H.-J. Park, J.-G. Ahn, K.-H. Song, "Fiber-to-the-home services based on wavelength-division-multiplexing passive optical network", J. Lightwave Technol. 22, 2582 (2004). CrossRef C.W. Chow, C.H. Yeh, "Using Downstream DPSK and Upstream Wavelength-Shifted ASK for Rayleigh Backscattering Mitigation in TDM-PON to WDM-PON Migration Scheme", IEEE Photon. J. 5(2), 7900407 (2013). CrossRef J. He, D. Yang, L. Chen, "A full-duplex radio-over-fiber system with differential phase-shift keying signals", J. Phys. Conf. 276, 012062 (2011). CrossRef L.Y. Chan, C.K. Chan, D.T.K Tong, E Tong, L.K. Chen, "Upstream traffic transmitter using injection-locked Fabry-Perot laser diode as modulator for WDM access networks", Electron. Lett. 38(I), 43 (2002). CrossRef Z. Xu, Y. J. Wen, C. J. Chae, Y. Wang, C. Lu, Proc. Opt. Fiber Commun. Conf. (OFC06), JThB72 (2006). C.H. Yeh, C.W. Chow, H.Y. Chen, J.Y. Sung, Y.L. Liu, "Demonstration of using injection-locked Fabry-Pe?rot laser diode for 10?Gbit/s 16-QAM OFDM WDM-PON", Electron. Lett. 48(15), 940 (2012). CrossRef J. H. Lee et al., "Single, Depolarized, CW Supercontinuum-Based Wavelength-Division-Multiplexed Passive Optical Network Architecture With C-Band OLT, L-Band ONU, and U-Band Monitoring", IEEE J. Light. Tech. 25(10), 2891 (2007). CrossRef Q.T. Nguyen et al., "Bidirectional Transmission in Colourless WDM-PON based on Injection-Locked Fabry-Perot Laser at 2.5 Gbit/s using Low-Cost Seeding Source", in: Proc. Eur. Conf. Opt. Commun. (ECOC), Vienna, Austria, Paper 6.5.1, (2009). DirectLink T. Yoshida, S. Kimura, H. Kimura, K. Kumozaki, T. Imai, "A new single-fiber 10-gb/s optical loopback method using phase Modulation for WDM optical access networks", J. Lightw. Technol. 24,786 (2006) CrossRef W. Hung, C.-K. Chan, L.-K. Chen, F. Tong, "An optical network unit for WDM access networks with downstream DPSK and upstream remodulated OOK data using injection-locked FP laser", IEEE Phot. Techn. Lett. 15(10), 1476 (2003). CrossRef OptiSystem Package from Optiwave.

차세대 무선 브로드밴드 산업 동향과 활성화 방안

Ongoing advances in wireless broadband technologies can affect all of industrial society. As new wireless broadband technologies emerge, they will improve competition between established industries and their current services and produce new industries and new converged services. This paper analyzes the trend of next-generation wireless broadband and suggests ways of activating the industry further. To this end, we analyze the trend for previous wireless broadband industries and find out three influential factors (content, wireless network technology, and service) that will produce the continued growth of wireless broadband. Using these three factors, we propose a network technology-driven growth model. Based on that model, we offer activation plans for next-generation wireless broadband industries. This study thus provides an insightful perspective for next-generation wireless broadband industries by establishing additional useful guidelines for developing wireless broadband industries in the future.

Smart Downlink Scheduling for Multimedia Streaming Over LTE Networks With Hard Handoff

This paper presents a novel smart downlink scheduling scheme to enhance the performance of multimedia transmission over long-term evolution (LTE) networks. LTE represents a promising framework for the next-generation broadband multimedia services because of its significantly increased data rate over 3G cellular networks. However, the current LTE scheduling scheme has largely been designed for general data traffic without adequate consideration of multimedia characteristics. Moreover, the hard handoff (HO) procedure adopted in LTE will further degrade the multimedia services when the mobile user moves from one cell to another. Even with increased data rate, current LTE systems still cannot deliver the expected quality of service (QoS) to the mobile users under various mobility scenarios, especially when the hard HO is evoked. Aiming at overcoming these major challenges, we develop in this paper a QoS-driven smart downlink scheduling scheme for enhanced multimedia transmission over LTE networks. The proposed design shall take the following QoS metrics into consideration: 1) the delay constraint of voice-over-Internet protocol flow; 2) the packet deadline of video flow; and 3) the service degradation induced by the hard HO procedure. We achieve the design objectives by creating three QoS-driven operational control modules: 1) a transmission delay control module to ensure the on-time arrival of various types of multimedia data; 2) an HO control module to warrant continuous multimedia services when the user moves across a cell boundary; and 3) a resource allocation module to strategically map the requested flows to best fit radio resource blocks. The simulation results confirm the performance gain of the proposed scheme.

Optimal location planning of relay-based next generation wireless access networks

Use of relays is considered one of the most effective ways for capacity enhancement and coverage extension in next-generation broadband wireless access networks (BWAN). The paper investigates the location planning problem in BWANs, aiming at an optimal deployment of relay stations and base stations to enhance capacity. We develop formulations in mixed integer linear programming to effectively capture various planning policies that govern relay and base station placement. Case studies are conducted to verify the effectiveness of the proposed formulations. We show that the same traffic demand can be satisfied with up to 73 % fewer relay stations with a slight (6 %) decrease in the overall network capacity, compared with our benchmark. Based on the developed formulations, we introduce a maximin objective function to properly distribute excess bandwidth to all subscriber stations rather than assigning it to a single one, which surprisingly leads to a significant gain in the rate allocated to each subscriber station.

Broadband Diffusion and Firm Performance in Rural Areas: Quasi-Experimental Evidence

This article analyzes the causal impact of advanced broadband accessibility on firm performance. We exploit a unique local policy intervention of a staged broadband infrastructure installation across rural municipalities in the Province of Trento (Italy), generating a source of exogenous (spatial and temporal) variation in the provision of next-generation broadband technology (ADSL2+).Employing a difference-in-differences strategy and using longitudinal firm-level data on annual balance sheet information of corporate enterprises, we show that ADSL2+ availability is associated with a significant increase in annual sales turnover of about 40 percent and an increase in value added of roughly 25 percent over the period of two years. The positive effect is found to be rather stable for different lengths of treatment exposure and across industrial sectors. However, no significant effects are found with respect to number of employees. Placebo estimations support a causal interpretation of our results. Overall, established corporate enterprises in 'underserved' rural and remote areas appear to profit considerably from enhanced broadband delivery programs in terms of economic performance.

High-level stakeholders’ insights on readying Australia for Next Generation Broadband

We interviewed 24 high-level representatives from across Australian society and industry to explore (a) what changes might occur in each sector once next generation broadband (NGB) is widely available and (b) what action is needed to prepare for these changes. Most participants expected NGB to have a positive and profound effect on business and daily life in Australia. However, Australian organisations had been slow to engage with the opportunities offered by NGB. They were also concerned that certain groups could get left behind through digital divide. They called for government to better articulate the role of NGB in supporting Australia’s future social and economic prosperity, to act as a front-runner in the use of the new technology and to deliver policy addressing barriers to uptake. Leadership was also needed from public and private organisations, both to build the nation’s digital capability and in utilising NGB to transform business processes.