Advanced PON topologies with wireless connectivity

“This material is presented to ensure timely dissemination of scholarly and technical work. Copyright and all rights therein are retained by authors or by other copyright holders. All persons copying this information are expected to adhere to the terms and constraints invoked by each author's copyright. In most cases, these works may not be reposted without the explicit permission of the copyright holder." “Copyright IEEE. Personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution to servers or lists, or to reuse any copyrighted component of this work in other works must be obtained from the IEEE.”The interoperability of wireless and PON networking solutions is investigated to reduce deployment expenditure by means of centralised network management while providing ubiquitous access connections and mobility. Network modelling in the physical layer of WiMAX channel transmission based on FDM over legacy PONs has demonstrated EVMs below -30 dB and error-free multipath transmission. In addition, the development of a dynamic MAC protocol suite has been presented to assign bandwidth between the OLT and ONU BaseStations over a multi-wavelength, splitter-PON topology to demonstrate converged network scalability. This has been achieved by managing data-centric traffic with quality of service in view of diverse multi-user access technologies

A multi-wavelength access network featuring WiMAX transmission over GPON links

“This material is presented to ensure timely dissemination of scholarly and technical work. Copyright and all rights therein are retained by authors or by other copyright holders. All persons copying this information are expected to adhere to the terms and constraints invoked by each author's copyright. In most cases, these works may not be reposted without the explicit permission of the copyright holder." “Copyright IEEE. Personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution to servers or lists, or to reuse any copyrighted component of this work in other works must be obtained from the IEEE.”An IEEE802.16e compliant PON architecture with wavelength band overlay has been demonstrated. Transparent transmission of mobile-WiMAX RF channels over multi-wavelength GPON links, based on FDM, has demonstrated at remote receivers standard WiMAX EVM figures with 1E-11 GPON bit-error-rates

Full-Service MAC Protocol for Metro-Reach GPONs

“This material is presented to ensure timely dissemination of scholarly and technical work. Copyright and all rights therein are retained by authors or by other copyright holders. All persons copying this information are expected to adhere to the terms and constraints invoked by each author's copyright. In most cases, these works may not be reposted without the explicit permission of the copyright holder." “Copyright IEEE. Personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution to servers or lists, or to reuse any copyrighted component of this work in other works must be obtained from the IEEE.”An advanced medium access control protocol is presented demonstrating dynamic bandwidth allocation for long-reach gigabit-capable passive optical networks (GPONs). The protocol enables the optical line terminal to overlap the idle time slots in each packet transmission cycle with a virtual polling cycle to increase the effective transmission bandwidth. Contrasting the new scheme with developed algorithms, network modeling has exhibited significant improvement in channel throughput, mean packet delay, and packet loss rate in the presence of class-of-service and service-level differentiation. In particular, the displayed 34% increase in the overall channel throughput and 30 times reduction in mean packet delay for service-level 1 and service-level 2 optical network units (ONUs) at accustomed 50% ONU load constitutes the highest extended-reach GPON performance reported up to date.Peer reviewe

Scalable cell-free massive MIMO systems with hardware impairments

© 2020 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works. This is the accepted manuscript version of a conference paper which has been published in final form at https://doi.org/10.1109/PIMRC48278.2020.9217151Despite the deleterious effect of hardware impairments (HWIs) on wireless systems, most prior works in cell-free (CF) massive multiple-input-multiple-output (mMIMO) systems have not accounted for their impact. In particular, the effect of phase noise (PN) has not been investigated at all in CF systems. Moreover, there is no work investigating HWIs in scalable CF (SCF) mMIMO systems, encountering the prohibitively demanding fronthaul requirements of large networks with many users. Hence, we derive the uplink spectral efficiency (SE) under HWIs with minimum mean-squared error (MMSE) combining in closed-form by means of the deterministic equivalent (DE) analysis. Notably, previous works, accounted for MMSE decoding, studied the corresponding SE only by means of simulations. Numerical results illustrate the performance loss due to HWIs and result in insightful conclusions

POSITIVE RELATIONS OF PHYSICAL FITNESS AND EXERCISE INTERVENTION PROGRAMS WITH MOTOR COMPETENCE AND HEALTH-RELATED QUALITY OF LIFE IN DEVELOPMENTAL COORDINATION DISORDER: A SYSTEMATIC REVIEW

Developmental Coordination Disorder (DCD) is an impairment in the development of motor coordination creating varied problems and difficulties in children’s and adolescent’s daily life activities. As a result, the avoidance of participating in physical activity leads in low levels of fitness and also in secondary social and emotional problems. Fitness levels in children and adolescents with DCD have been recognized as an important factor which influences their performance in daily activities and has a positive impact on their health-related quality of life (HRQOL). Surveys showed that every domain in HRQOL (motor, cognitive, emotional, social) is significantly lower in children with DCD compared to their peers. These data showed that intervention is very important for improving motor skill performance and HRQOL, too, in children and adolescents with DCD. The present study aimed to systematically review the literature published in peer reviewed journals and to summarize information about possible relationships between intervention approaches focused on physical fitness and exercise, participation in physical activity and HRQOL, in children and adolescents with DCD. Studies which examined the effect of fitness and exercise intervention programs on motor competence and HRQOL in children and adolescents with DCD were also, included. The review of the literature has shown that several intervention programs developed for DCD population, focusing to improve motor ability, derived from occupational therapy, physiotherapy, medicine, dietetics and education scientific areas. Generally, the present review focused on two basic approaches in clinical practice regarding intervention programs for DCD individuals: task-oriented and process-oriented approach. The task-oriented approach aims to improve the performance of a specific skill and on the other hand the process-oriented approach aims to identify the underlying processes or dysfunctions which the individual has not developed adequately according to his/her age, although they are considered to be necessary for successful performance and acquisition of motor skills. Children and adolescents with DCD seemed to report poorer ΗRQOL than their typically developing peers. However, HRQOL in children and adolescents with DCD needs further investigation. In addition, there is a need of research in interventions focused on fitness and exercise programs with an ultimate goal to improve motor ability and HRQOL too; through participation in such interventions children and adolescents with DCD, may be possible to break the negative cycle of physical activity avoidance, reversing it to a positive one. It is concluded that, there are possible positive relationships between fitness and exercise intervention programs, motor competence and HRQOL in children and adolescents with DCD. Future research should focus on examining whether and how such interventions may eliminate functional constraints leading to an engagement in the positive cycle of physical activity, with a further improvement in HRQOL in DCD population.  Article visualizations

A complete 8-GHz QPSK-MODEM featuring novel subcarrier and data synchronization for optical communications

Peer reviewe

Transparent wireless transmission over the ACCORDANCE optical/wireless segment

“This material is presented to ensure timely dissemination of scholarly and technical work. Copyright and all rights therein are retained by authors or by other copyright holders. All persons copying this information are expected to adhere to the terms and constraints invoked by each author's copyright. In most cases, these works may not be reposted without the explicit permission of the copyright holder." “Copyright IEEE. Personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution to servers or lists, or to reuse any copyrighted component of this work in other works must be obtained from the IEEE.”Following the evaluation of FP7 proposals under the Call 4 objective, the network of the future, the STREP project ACCORDANCE has been funded to develop a converged copper/optical/radio OFDMA-based access network with high capacity and flexibility. The ACCORDANCE topology supports the integration of technologies and the interoperability of protocols in the form of distinctive network segments, e.g. legacy xPONs, xDSL, legacy wireless etc., through the application of OFDM(A) to provide segment access to and from the network central office. In particular, ACCORDANCE introduces the integration of dominant wired and wireless technologies in a hybrid network segment for greater flexibility and mobility at ease of last-mile implementation. To that extent, a converged passive optical network architecture supporting standard WiMAX/LTE signal formats by means of FDM subcarrier transmission downstream to remote ONU/BSs has been in the focus of this paper. Transparent operation for five FDM subcarriers carrying 3.5 GHz WiMAX channels has been demonstrated with measured EVMs of -31 dB obtained at selected ONU/BS antenna inputs for all subcarriers spacing. In addition, external versus direct modulation evaluation measurements exhibited superior SFDR figures for the former compared to the latter allowing for increased number of subcarriers in a FDM window and consequently network scalability

A full-duplex access network based on CWDM-routed PONs

“This material is presented to ensure timely dissemination of scholarly and technical work. Copyright and all rights therein are retained by authors or by other copyright holders. All persons copying this information are expected to adhere to the terms and constraints invoked by each author's copyright. In most cases, these works may not be reposted without the explicit permission of the copyright holder." “Copyright IEEE. Personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution to servers or lists, or to reuse any copyrighted component of this work in other works must be obtained from the IEEE.”The application of polarisation-division-multiplexing in presented, demonstrating full-duplex transmission in an access network architecture employing RSOA-based ONUs. Modelling of a single coarse-AWG OLT to transmit orthogonally-multiplexed burst-data and continuous-waves demonstrated crosstalk-free transmission up to 20km. ©2008 Optical Society of America

Multi-wavelength WiMAX-PONs with overlapping cells

An access network architecture integrating standard wireless signal formats over multi-wavelength splitter-PON based on radio over fiber (RoF) technology is demonstrated. Frequency division multiplexing (FDM) is applied to address individual base stations sharing a single wavelength. The extended wavelength band overlay overcomes the need for complex dispersion compensation techniques as it avoids the use of high frequency subcarriers in the FDM window. Also, it achieves enhanced network scalability to previously reported converged architectures as well as reduced component cost. Significantly, extended features of wireless networks have been presented through the application of overlapping cells to overcome the wireless spectrum congestion beyond current deployment scenarios and provide resilience for legacy PONs. To evaluate the network transmission characteristics, multiple IEEE802.16d channels, with 70 Mbits/s downstream and 40 Mbits/s upstream data rates, are frequency shifted around the same RF carrier and transmitted on two different wavelengths. The obtained results has demonstrated EVMs of -31 dB at ONU/BS remote antenna inputs and minimum 10-4 BERs bidirectionally over combined 20km and faded 330m overlapping micro-cells circumference without any error coding or relay techniques. The application of low-cost long-wavelength VCSEL array in upstream for colorless transmission demonstrated 0.7 dB power penalty to the received WiMAX channels in the OLT.Peer reviewe

A G.984 GPON Exhibiting Multi-Wavelength Protocol Functionalities

A Gigabit Passive Optical Network (GPON) upstream-map frame- format enhancement has been developed to accommodate dynamic multi wavelength (DMW) transmission over splitter-based GPONs. Accordingly network functionality has been supported by means of an algorithm, managing bandwidth allocation among utilised wavelengths in a dynamic two dimensional protocol. Modelling of the performance characteristics of the DMW-GPON topology in OPNET has demonstrated a minimum of 100 Mbit/s bandwidth provision for each of 32 Optical Network Units (ONUs) with a maximum 0.085 s packet delay for the worst performing lower service level agreement (SLA) ONUs