This PDF file contains the front matter associated with SPIE Proceedings Volume 11307, including the Title Page, Copyright information, Table of Contents, Author and Conference Committee lists

A passive optical network (PON) is a promising candidate to efficiently accommodate the packet-based Mobile Fronthaul (MFH) in 5G and beyond-5G base stations. However, to apply the PON to the MFH, there are some technical issues to be resolved, such as large uplink latency and wavelength drift. This paper describes PON control technology for providing low-latency transmission and that for providing remote wavelength maintenance in the MFH with the PON. Experiments show that our technologies can achieve the less than 50 μs bandwidth-control latency and the wavelength-drift mitigation.

Key digital signal processing (DSP) techniques with advanced modulation formats are proposed and discussed in O-band/ C-band beyond 100G signal transmission with low cost intensity modulation and direct detection (IM/DD). Enabling by DSP in the transceiver, beyond 100G PAM, DMT and Spectra efficient frequency division multiplexing (SEFDM) signal transmission are demonstrated in optical short reach for mobile fronthaul.

We will report on one of the first demonstrations of mobile cloud use cases in the 5G paradigm for smart transport systems in a university campus setting in the Philippines. Globally, 2019 has been identified as a watershed year for the demonstration of business cases for 5G, and this year many network operators are exploring how quickly and effectively traction and engagement can be gained from existing business and partner relationships. The Ateneo de Manila University is a unique academic partner as its Loyola Heights campus houses an eclectic collection of research institutions, grade school to graduate school units and a creative hub for the arts. In this presentation we will provide an overview of our ongoing efforts to deploy, commission and explore use cases in 5G communications for a 5G campus testbed. In particular we will discuss implementations of caching, mesh networking, and the first demonstration of a smart transportation hub using 5G and mobile cloud architectures in academic settings as well as for applications in sustainable and resilient communities.

The fifth-generation (5G) of mobile systems is considered a key enabler technology for autonomous driving vehicles. This is due to its ultra-low latency, high-capacity, and network reliability. In this paper, a full end-to-end 5G automotive platform for benchmarking, certificating, and validating distinct use cases in cooperative intelligent transport systems, is proposed. Such an automotive platform enables fast service creation with open-access and on demand services designed for public use as well as for innovative use cases validation such as highway chauffeur system, truck platooning, and real-time perceptive intersection, to name a few. The distinct set of technologies that compose the end-to-end 5G automotive ecosystem framework is described. The holistic 5G automotive ecosystem can handle system and networking interoperability, handover between mobile cells, mobile edge computing capabilities including network slicing, service orchestration, and security. Moreover, the latency performance of a vehicular network with two vehicles is experimentally addressed by using the holistic platform. Up- and down-stream packet transmissions between the two vehicles in an open environment with real-traffic conditions is considered. The results pave the way towards latency levels within the range of 5G key performance indicators and consequently enabling autonomous driving systems. The 5G platform can be further useful for governmental agencies to define new policies and regulations, being able to address critical points such as data protection, liability, and legal obligation, regardless whether systems are partially or fully automated.

Digital radio-over-fiber (D-RoF) transmission technology is a favorable candidate for mobile fronthaul networks because it enables robust data transmission against noise, channel degradations, and nonlinear impairments in the link. Error-free transmission can also be achieved when the system is combined with forward error correction coding. However, the bandwidth efficiency of traditional D-RoF technology is relatively low because it applies uniform analog-to-digital converters with an ultra-high resolution and transmits the binary codes after digitization. In this work, the current progresses of 5G MFH have been reviewed and multiple digital transmission techniques have been discussed based on our previous works. The first method is about fast statistical estimation, which is computational efficient and particularly designed for wireless signals with Gaussian distributed amplitudes. Then, Lloyd algorithm will be introduced, which can re-allocate the quantization levels to achieve a best fit with the probability distributions of the wireless signal’s amplitudes. Thus, Lloyd algorithm can be applied to any kinds of wireless modulation format with a random amplitude distribution, but a trade-off needs to be considered between computational complexity and compression ratio. Differential coding-based compression techniques are also discussed, where we have proposed an adaptive low-complexity differential encoder based on least-mean-square (LMS) algorithm to further improve the compression ratio and be adaptive to the signal’s dynamic change. By jointly using Lloyd algorithm based quantizer and an LMS differential encoder, significant improvements on compression efficiency can be achieved. The Lloyd algorithm and differential coding have been jointly applied in a data-compressed mobile fronthaul testbed with a net data rate of 100 Gbit/s, which is able to comprise 45×120- MHz 5G NR carriers with lower-than 1% EVM.

The explosive growth of mobile applications, e.g., ultra-high definition video streaming, virtual reality/augmented reality (VR/AR) wearables, incurs lots of changes in 5G network of its reliability, coverage, transmission throughput and received quality of service (QoS). Therefore, to make 5G a reality, Fiber-Wireless Integration and Networking (FiWIN) is the key architecture in serving such diverse user scenarios, which provides a comprehensive network design for signal delivery. In this paper, some of the great challenges in 5G mobile fronthaul and the possible solutions will be discussed. In particular, we will review the recent breakthroughs in the FiWIN research center of the digitally spreading OFDM, polarization division multiplexing (PDM) radio-over-fiber (RoF), and beamforming enhanced mobile fronthaul. From the network perspective, by employing the 5G new radio and dense small cells deployment, the 5G wireless environment could become sophisticated, and the unexpected interference would cause a significant received performance declination. In this case, a spreading OFDM exhibit a superior received performance over the typical OFDM is considering as a promising signal format. While, the photonic-aided RoF system greatly simplified the 5G small cell hardware design. In order to maintain that beneficial feature, a self-polarization PDM scheme may be applied in mobile fronthaul for increasing the channel capacity and network coverage. The narrow beam-width property of 5G new radio reduces the tolerance of antenna misalignment. To address such issue, we will present the future-proof experiment of the fiber-wireless integration network with a 1-by-4 beamforming receiver with full reception angles (±90o) and signal waveforms transparency.

This paper proposes and demonstrates experimentally, for the first time to our knowledge, a software-defined beamforming implementation based on the precise timing control of the samples generated by different digital-to-analog converters (DACs) modulating a single laser light and transmitted over a multicore fiber (MCF) optical fronthaul.

Optical fronthaul systems based on standard single-mode fiber exhibit the problem of coherent signal distribution, as the signals for each antenna element are transmitted in wavelength division multiplexing (WDM), experiencing different delays from different chromatic dispersion (CD) values. Moreover, CD dynamics are different for each WDM signal due to temperature and vibration, making difficult to control the delay of the signals for the different antenna elements. This limitation can be solved using an optical fronthaul based on MCF, where the signals for the different antenna elements are transmitted through the different cores with spatial division multiplexing at the same wavelength from a single laser source.

In this work, the software-defined beamforming functionality over a MCF optical fronthaul is proposed and demonstrated experimentally with the transmission of an LTE-like signal in the 700 MHz frequency band over 1 km of 7-core fiber. The LTE signal is steered ±45° by defining a delay of ±1 digital sample at 2 GS/s (±500 ps), ensuring error vector magnitude (EVM) compliant transmission after 1 km of MCF. This paper also demonstrates that, increasing the DAC sampling frequency to 5 GS/s, a higher density area can be covered.

An IFoF/V-band link is experimentally presented in a 100MBd QPSK downlink transmission across 7km fiber by a high-power EML and over-the-air by 60GHz beamforming antenna with 32-radiating elements, comprising the first demonstration of a cost-effective end-to-end directional Fiber-Wireless link for dense 5G millimeter-wave networks.

The authors propose a novel, multifunctional approach to the problem of demultiplexing closely spaced channels sourced from an optical frequency comb. This solution, based on an externally injected laser, combines the functionality of a tunable demultiplexer, an ultra-low noise amplifier and a modulator, using a single device. Such a device can serve as an optimum transceiver for next generation broadband access (wired and wireless) networks.

This paper reports a dual-wavelength photonic beamformer implementing optical true time delay (OTTD) to realize microwave beam steering. The beamformer is capable of providing independent delay tuning to two separate beams modulated on different optical carriers. The integrated TTD chip includes a multiplexer that combines the two input wavelengths, an optical sideband filter (OSBF) and optical ring resonators (ORRs) that induce different optical delays. The ORRs are thermo-optically tuned to change the coupling ratio and obtain an incremental delay in each optical path. The experimental demonstration includes a full-compliant WiFi channel (at 5 GHz or 18 GHz RF bands) transmitted in one optical carrier and a WiMAX channel (at 5.4 GHz or 19 GHz RF) in another optical carrier operating in the resonance slope of the ORRs. The different antenna elements are connected with 1-km of 7-core fiber, achieving EVM-compliant levels at the antennas with beam-steering angles ranging from -40° to +80°. The performance comparison considering single-carrier broadband RF signals at the same frequency bands is also reported in this work.

Recently it has been shown that standard single-mode fibers, which support two LP modes around 850 nm, can yield high modal bandwidth with graded-index profile design. A transmission system using such fibers along with 850 nm single mode VCSEL transceivers offers a potentially cost-effective high-bandwidth solution for data center applications and future high-speed short distance communications. The system reach highly depends on the modal bandwidth of the fiber. In this context, it is of interest to explore the characterization method of the modal bandwidth of two-mode and few-mode fibers, especially if the method can be simpler than traditional methods used for 50-μm core multimode fiber. To address this issue, we propose a simple and robust method for two-mode and few-mode fiber modal delay and bandwidth measurements using frequency domain method. An analytical transfer function model was formulated and achieved excellent agreement with experimental results. The model allows one to extract the modal delay based on one single measurement, regardless of the launch condition. The transfer function and hence modal bandwidth with arbitrary launch condition can be calculated, from which we define a worst-case modal bandwidth that can gauge the fiber modal bandwidth under general conditions. The analytical model is also generalized to consider higher-order modes and additional bandwidth degradation effects. Through the detailed study, we show that the simple frequency domain measurement method as facilitated by the analytical model can deliver a full set of modal delay and modal bandwidth information that otherwise requires more complex method like differential mode delay measurements.

To meet the ever-growing demand for faster wireless communications, optical wireless communication (OWC) has been extensively developed, which can bring a huge improvement in communication capabilities, both in terms of ultra-high capacity per user and in terms of electromagnetic interference-free wireless communication [1-2]. However, one fundamental challenge for OWC arises when the direct pathway between transmitter and receiver is obstructed by an obstacle. When an optical beam is illuminated on a rough surface, the light is scattered to different directions, which results in the near-isotropic, speckled optical intensity distribution of the diffused light. Therefore, the intensity of the diffused light is inherently much lower than that of a collimated incident light arriving directly at the receiver. Usually, the proposed solutions do not address the diffusion mechanism itself but instead of focusing on the compensation of the diffusion-caused loss by increasing the system power, or they avoid diffuse reflection and/or scattering altogether, i.e., using a near-perfect mirror as a reflector. As a long-standing challenge, such diffuse loss critically hinders the application of OWC. Here, a novel non-line-of-sight (NLOS) beam reconfigurable optical wireless data transmission system for energy-efficient communication is proposed and experimentally verified. This is an overview of our previous work which is published on Light: Science&Applications [3]. By spatially modulating the light incident on a rough surface using a spatial light modulator (HOLOEYE PLUTO Phase Only SLM), the diffused light is focused on an optical wireless receiver, which breaks the NLOS limitation of OWC. A record-breaking 30-Gbit/s orthogonal frequency division multiplexing (OFDM) signal is transmitted over a diffused 110-mm optical wireless link with >17-dB gain, in an angular range of 20°. In this experiment, the 1550-nm laser source is used to match the well-established fibre-system. The OFDM signal is modulated onto the optical domain and amplified to the eye-safety power limit of 10 dBm. Then the light is collimated and delivered to an SLM. The angle between the incident beam and the reflected beam is 45°. To match the Gaussian beam (size), the central 1024-by-1024 pixels are activated, which are further grouped into segments of 64×64 pixels, yielding a total of 16×16 segments for data transmission. All pixels in a segment can be phase modulated from 0 to 2π in increments of π/8 individually. The phase-compensated beam is illuminated onto a rough barrier, which emulates the rough surface of ceilings or walls in an indoor scenario. Here, a Thorlabs polystyrene screen (EDU-VS1/M) and a sandblasted aluminium film are verified. To collect the diffused light to realize a large-capacity transmission, the light is coupled into a single-mode fibre using a collimator. Enabled by the feedback signal from a power meter, the received optical signal can be optimized by using the wavefront shaping [4]. The data-rate of 30 Gbit/s with blocked sightlines is achieved using the stepwise sequential algorithm [4].

We investigate channel characterization for wireless body-area networks (WBANs) in medical applications using optical signal transmission. More specifically, we focus on uplink communication from a central coordinator node (CN), placed on the patient's body, to an access point (AP) in a typical hospital room, which is usually referred to as extra-WBAN link. Using a ray-tracing based approach, we quantify the main characteristics of the optical channel while considering the effects of body shadowing and mobility (accounting for body movements and user global mobility inside the room). Based on the presented results, we discuss the impact of the positions of the CN and the AP on the link parameters. We also evaluate the link performance based on the outage probability criterion, and further quantify the performance improvement achieved by using multiple APs in the room.

There exists a demand for radiation-safe and high-speed communication systems available to public users in the fifthgeneration (5G) communication and beyond. In this regard, visible light communication (VLC) stands out offering multiGigabit-per-second (Gbit/s) data transmission, energy efficiency and illumination, while being free from electromagnetic interference. Here, we report a high-speed VLC link by using a 443-nm GaN-based superluminescent diode (SLD) and bit-loading discrete-multiple-tone (DMT) modulation. Analysis of the device characteristics and modulation parameters shows a feasible bit allocation of up to 256-QAM while obtaining up to 3.8 Gbit/s data rate. These results, together with the electro-optical properties of the SLD such as being droop-free, speckle-free and high-power, make it an attractive solution for the future of public communications and smart lighting, while complementing traditional fiber-based and millimeter-wave technology.

We recently demonstrated modulators based on plasmonic technology displaying a flat frequency response reaching 500 GHz, high linearity and power handling. We discuss their potential for extending microwave photonics (MWP) applications to the sub-THz range, demonstrating analog photonic links with bandwidth in excess of 100 GHz and the capability of direct mm-wave to optical conversion.

We investigate an approach to short and medium-range wireless communications based on the use of terahertz beams possessing an orbital angular momentum (OAM) that allows for noise-resistant broadband carrier. A the- oretical model of the proposed beams generation is developed and numerical predictions are given for propagation and visualization of complex-structured THz beams, including ones carrying a unit topological charge on a large number of spectral components of broadband terahertz radiation. The assessment method which in our case is terahertz pulse time-domain holography allows for analyzing spatio-temporal and spatio-spectral evolution of arbitrary shaped THz wave trains during their propagation in free space and interaction with obstacles.

In this paper, we propose a multi-user (MU) multiple-input multiple-output (MIMO) optical orthogonal frequency division multiplexing (OOFDM) aided index modulation (IM) assisted indoor visible light communication (VLC) system. The IM principle is applied to the OOFDM scheme invoking block diagonalization based precoder (BDP) for a MU-VLC system, where a so-called data stream interleaver (SI) is introduced to further improve the system's performance. Simulation results show that the proposed hybrid MU-VLC system with SI is capable of outperforming its conventional counterparts in terms of bit error rate (BER) in indoor scenarios.

The current constant growth in mobile networks’ traffic demands, owing to the popularization of cloud and streaming services on personal devices, requires architectural changes to fulfill all the new 5G mobile network requirements and specifications. Cloud access radio network (C-RAN) architecture in combination with the massive deployment of small cell antenna sites has recently been proposed as a promising solution, though demanding, for high-capacity mobile fronthaul links. An efficient way to perform that connectivity is to make use of the deployed passive optical networks (PONs) where wireless and wired services may be converged for distribution purposes. Non-orthogonal multiple access (NOMA) combined with multi-band carrierless amplitude phase modulation (NOMA-CAP) has recently been proposed as a promising 5G and beyond modulation format candidate to increase the capacity and flexibility of future mobile networks. In this paper, for the first time we demonstrate the convergence of a NOMA-CAP wireless waveform with a single-carrier wired signal in a PON scenario using radio-over-fiber (RoF) technology. Specifically, fifteen NOMA-CAP bands with two power levels—hence doubling the capacity—transmit 15 Gb/s multiplexed with a digital 10 Gb/s fourlevel pulse amplitude modulation (PAM-4) signal for downlink application. The results show that the crosstalk interference can be minimized by controlling the amplitude relation between the NOMA-CAP and PAM-4 signals to maximize the wireless transmission bandwidth. Moreover, successful transmission over 25 km of standard single-mode fiber is also demonstrated with negligible transmission penalty.

In this paper, a dense wavelength division multiplexing passive optical network (DWDM-PON) using cross seeding system is designed and evaluated. This system utilizes 16 channels with low channel spacing of 12.5 GHz. Upstream (US) capacity is enhanced to 2.5 Gb/s over 25 km single mode fiber (SMF) transmission. This optical network has a downstream (DS) capacity of 10 Gb/s. A noteworthy average bit error rate (BER) of 10^-13 is achieved during system evaluation process. A successful mitigation for Rayleigh backscattering (RB) is achieved comparing to conventional bidirectional wavelength division multiplexing passive optical network (WDM-PON).

In the visible light (VL) communication based on the multicolor channel between colored LEDs and photodiode, a uniform performance on color channel may be desired, and VL communication services using multiple color channels should be attained by only one VL receiver. However it has been known that the received signal has the severe color distortion by the receiver performance variation on multicolor channels since photodiode produce more electrical current on red color than on green or blue color channel. In this paper we estimate the compensation extent of the color distortion in advance by color map and utilize the optimal VL transceiver circuit for distortion-less VL communication in the multicolor VL channel. We can see that the conventional technique without any compensation function of color distortion effect meets a failure in the color VL communication trial because of the different VL communication distance on each color VL channel, but the proposed scheme has no distortion due to the performance variation of each color VL channel in the overall range of communication distance.