Ultra-wideband Services Research Articles

Mobile Learning New Trends in Emerging Computing Paradigms: An Analytical Approach Seeking Performance Efficiency

Mobile learning (m-learning) adoption has increased and shall be demonstrated superior performance by implementing related computing paradigms, such as IoT, edge, mobile edge, fog, AI, and 5G. Mobile cloud architectures (MCAs) enable m-learning with several benefits and face limitations while executing real-time applications. This study investigates the state-of-the-art m-learning architectures, determines a layered m-learning-MCA obtaining numerous benefits of related computing paradigms, and expands m-learning functional structure. It evaluates m-learning performance across the four physical layer’s MCAs—distance cloud, cloudlet, operator-centric cloud, ad hoc cloud, and emerging computing architectures. Surprisingly, only distance-cloud MCA is adopted for developing m-learning systems by ignoring the other three. Performance evaluation shows m-learning gets terrific benefits and users QoE in related computing paradigms. Mobile edge computing offers ultralow latency, whereas the current architecture improves task execution time (1.87, 2.01, 2.63, and 3.97) for the resource-intensive application (i.e., 4.2 MB). Fog using AI algorithms is exceptional for more complex learning objects, IoT is superior for intelligent learning tools, and 5G ultrawideband services are more significant for intelligent video analytics. These findings help learners, educators, and institutions adopt an appropriate model for achieving their academic objectives across educational disciplines. The presented approach enables future research to design innovative architectures considering resource-intensive m-learning application execution requirements, such as video content analytics and virtual reality learning models.

Opportunities and Challenges of mmWave NR

The realization of a seamless, fully connected world requires enhancements to our current communications technology, from both a network infrastructure perspective and a user equipment (UE) perspective. These demands are directly driven by the consumer’s expectations, application requirements, and saturation of frequency bands used in current spectrum. The fifth generation (5G) of mobile communication networks, and specifically millimeter-wave (mmWave) New Radio (NR), aims to enable this future with ultra-low-latency, ultra-wideband services, opening up a whole new era of applications and services, much like 4G Long Term Evolution (LTE) did a decade ago. To enable 5G, the Third Generation Partnership Project (3GPP) is focusing on defining the technical specifications for NR technology, as well as enhancements to the current LTE. However, enabling and launching 5G NR presents both technological opportunities and challenges. In this column, we explore how 5G mmWave challenges are being approached in 3GPP standardization and how solutions can enable the technology to help achieve broader bandwidths and harness some of the inherent benefits of higher-frequency communications.

Flexible Multiband OFDM Ultra-Wideband Services Based on Optical Frequency Combs

In the paper, a flexible multiband orthogonal frequency-division multiplexing (OFDM) ultra-wideband service based on optical frequency combs is proposed and experimentally demonstrated for 5G wireless communications. By using optical frequency comb technology, the flexibility and capacity of wavelength-division multiplexing passive optical networks (WDM-PONs) can be improved. Meanwhile, the different sub-bands of multiband OFDM ultra-wideband signals are modulated with different modulation formats to ensure the data rate needs of different users. An adaptively modulated 128-/64-/32-ary-quadrature-amplitude-modulation-encoded multiband OFDM ultra-wideband signal is generated. In addition, a joint channel estimation method with training sequences and pilot symbols is applied to improve system performance. After 50-km standard single-mode fiber transmission, the experimental results show that the proposed system can provide bandwidth resources for 15 end users with an average access rate of 1.781  Gb/s per user and a high data rate of 5.343  Gb/s.

Transparent UWB Antenna with IZTO/Ag/IZTO Multilayer Electrode Film

Ultra-wide band (UWB) antennas with transparent indium zinc tin oxide (IZTO)/Ag/IZTO multilayer electrode films are presented. The geometry of the radiator of the proposed UWB antenna is a simple semicircular shape, and acryl is used for the transparent substrate. Three types of proposed antennas are used for the comparison: first, an UWB antenna with a copper sheet only (CUWB); second, a transparent UWB antenna with a transparent radiator only (TRUWB); and, third, an entirely transparent UWB antenna (TUWB). The IZTO/Ag/IZTO multilayer electrode is fabricated by a physical vapor deposition process in the highly maintained vacuum. The transmittance of the multilayer film at 550 nm wavelength is over 80%, and the conductivity is 3,960,000 S/m. The proposed CUWB, TRUWB, and TUWB have peak gains of 4.17, 3.14, and 0.74 dBi and radiation efficiency levels of 84.8, 64.5, and 42.1% at the center frequency of UWB service (6.5 GHz), respectively.

Instances of Worst-Case Scenario Based Analysis Pushback by the FCC

The FCC frequently uses worst-case scenario analysis as the basis for its decisions. However, there are instances where the FCC pushes back on these worst-case scenarios. In these instances, the FCC bases its decision on the practical realities of a situation and adopts a final decision that balances a range of factors implicated in the situation. This pushback occurred in a variety of contexts including dismissing concerns about out-of-band emissions in an advanced wireless services rule change, balancing daytime-only AM radio station post-sunset power limits with interference concerns, adopting a procedure for setting a separation distance that reflects practical interference concerns, developing realistic restrictions for UHF noise figure requirements, dismissing interference concerns around the use of ancillary terrestrial services by mobile satellite service providers, considering a waivers request by ultrawideband service providers, and refusing to act on unrealistic interference scenarios when considering whether to approve new satellite services. Two factors were present in each of these decisions. First, the worst-case scenario was implausible because it required several unlikely events to occur simultaneously. Second, if the worst-case scenario dictated the decision, the FCC would be required to adopt a conservative approach that overvalued one factor relative to other important factors in the decision mix. Where the FCC rejected worst-case driven decision-making, it adopted a final decision that balanced a range of pertinent factors.

Very broadband PIFA antenna for mobile communications and ultrawideband services

ABSTRACTThis article describes a very wideband planar inverted‐F antenna antenna that covers the frequencies from 1.73 to 10.25 GHz with S11 < ‐10 dB. This wideband encompasses the operating bands of mobile services such as DCS, PCS, LTE, WiMAX, WiFi, Bluetooth, and the major part of the ultrawideband spectrum. This new antenna has adequate radiation characteristics and dimensions of 4 × 2 × 1 cm3 that are suitable to be integrated in mobile terminals. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:313–316, 2014

Photonic generation of ultrawideband signals based on frequency-dependent gain saturation in a reflective semiconductor optical amplifier

A novel scheme to generate ultrawideband (UWB) pulses with different polarities is proposed and experimentally demonstrated based on a reflective semiconductor optical amplifier (RSOA). Because the gain saturation in the RSOA is more evident when the injected optical signal has a lower modulation frequency, the RSOA operated at the gain saturation regime can shape a dark or bright return-to-zero pulse to a UWB pulse. An experiment is performed. The fractional bandwidth of the generated UWB pulse is more than 89%. The generated UWB signals with on-off keying format are transmitted in a 20km single-mode fiber. The power penalty is less than 1.2dB. Since the RSOA is possibly a key device in wavelength-division multiplexed passive optical networks (WDM-PONs), the proposed optical UWB generator can be used to provide UWB services in a WDM-PON system without significantly increasing the cost.

Small UWB antenna with bandstop function for wireless USB of mobile handsets

AbstractIn this letter, a small and an internal ultra‐wideband (UWB) antenna for wireless USB of mobile handsets is proposed for UWB service in which bandstop function of 5.8‐GHz wireless local area network band is required.The ground is partially removed and the microstrip feed line is gradually tapered to obtain enhanced impedance bandwidth. λ/4 short slots for bandstop function are modified into L‐type to be accommodated in a small‐sized antenna. From the measured results, wide bandwidth of 3.15–4.75 and 7.2–10.2 GHz is achieved while 5.8 GHz is notched. Three different shapes of conventional mobile terminals are also considered for measurement. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett, 54:438–441, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26551

A WDM-PON-Compatible System for Simultaneous Distribution of Gigabit Baseband and Wireless Ultrawideband Services With Flexible Bandwidth Allocation

In this paper, a novel and simple scheme to realize flexible access for gigabit wireline and impulse radio ultrawideband (IR-UWB) wireless services is proposed. The UWB signals are generated by multi-carrier upconverting and reshaping the baseband signals. The proposed system was experimentally demonstrated with the performances of 2.0-Gb/s data in both baseband and UWB formats after 46-km single mode fiber transmission and further 0.5-m wireless for UWB data. The flexibility of the system is confirmed by investigating the system performance at different data rates including 1.0 and 1.6 Gb/s. Optical wavelength independency and data-rate variability of UWB signal generation makes the system attractive for potential wireline and wireless applications in existing wavelength division multiplexing (WDM)-passive optical network (PON) systems.