Claudio Estevez

A Resilient Transport Control Scheme for Metro Ethernet Services Based on Hypothesis Test

This paper aims to enhance the transport services of Ethernet MANs by detecting congestion more accurately and responding to packet losses more adaptively. Traditional TCP was designed for best-effort networks, and cannot utilize available bandwidth efficiently in a broadband link. Most of the previous research addressed this problem by modifying the additive increase multiplicative decrease (AIMD) algorithm of TCP. In this paper, a novel resilient transport control scheme is proposed for Ethernet services that utilize a less aggressive congestion window reduction algorithm when a non-congested environment is detected. A stochastic model for packet loss is proposed, in which packet losses are expressed as a random function of congestion and random loss present in the network Transport layer congestion control is stated as a hypothesis test process; making decisions based on multiple ACK feedbacks. The new method can keep false-alarm probability under control and therefore it increases throughput significantly.

Performance Enhancement of OFDM-Based Systems Using Improved Parametric Linear Combination Pulses

Abstract As the demand for better performance increases in next-generation networks, such as 5G technologies, more efficient modulation techniques are required. In this work, we evaluate the performance of the improved parametric linear combination pulses (IPLCP) in orthogonal frequency division multiplexing (OFDM) based systems. OFDM-based systems are very sensitive to frequency offset errors, and are characterized by producing high peak-to-average power ratio (PAPR) values. The IPLCP is evaluated in terms of average inter-carrier interference power, average signal to interference power, PAPR, and bit error rate. Theoretical and numerical simulations show that the IPLCP pulse performs well in OFDM-based systems in comparison to other existing pulses.

Energy-Efficient Multi-Access Technologies for Very-High-Throughput Avionic Millimeter Wave, Wireless Sensor Communication Networks

In this paper, we investigate energy-efficient wireless over fiber access channel and link layer technologies using 60-GHz millimeter-wave (mm-wave) band for avionic very high throughput millimeter-wave sensor communication networks (VHT-MSCNs). An efficient architecture for wireless sensor network employing directional mm-wave wireless access technologies is proposed for systems that require very high throughput, such as high definition video signals, for sensing, processing, transmitting, and actuating functions. Comparisons among various multi-access techniques in terms of power and link layer operation efficiency are presented. A specific multi-access network design for VHT-MSCN is proposed and evaluated here, including energy consumption modeling and protocol frame configuration. A proof-of-concept testbed of the proposed very-high-throughput wireless over fiber sensor communication network using 60-GHz mm-wave radio-over-fiber (RoF) technology in downlink transmission and multi-access technique in uplink transmission has been designed and demonstrated.

A Carrier-Ethernet oriented transport protocol with a novel congestion control and QoS integration: Analytical, simulated and experimental validation

Carrier Ethernet is becoming the dominating backhaul network due to its flexibility, scalability, interoperability and low-cost. Carrier Ethernet networks (CENs) are inherently high bandwidth-delay product (BDP) networks, hence Traditional TCP, and similar variants, make undesirable choices of transport protocol mainly because of the aggressive multiplicative-decrease algorithm. The Ethernet-Services Transport Protocol (ESTP) has proven relieve the effects of the decrease algorithm by dynamically adjusting the transmission rate according to the level of congestion estimated in the network. It should be emphasized that most protocols detect congestion, but do not estimate the level of congestion. Also ESTP incorporates QoS information to further improve performance. In this work, a steady-state throughput analytical model of ESTP is derived, an experimental testbed is built and simulation results are obtained. All validation methods show good agreement.

Recent advances in Green Internet of Things

Environmental issues are acquiring more attention as the general public becomes more aware of the consequences that the environment degradation is capable of causing. This has triggered various initiatives, i.e., the IEEE Comsoc approved the technical committee of Green Communications and Computing, which aims at having a special task force focused on environmentally-friendly communication topics. In this work, some of the most recent advances in this field are discussed. The topics include energy efficiency, energy harvesting, and solutions to pollution issues all in the context of the Internet of Things (IoT), which is expected to have a great impact on the green topics.

Very-high-throughput millimeter-wave system oriented for health monitoring applications

Millimeter-wave transmission systems allow for very high throughput rates and broad bandwidths using wireless technology. Most Body Area Networks (BANs) work in the high MHz or few GHz range, which limit the channel capacity of the system. If the bandwidth is narrow, only low spectrally-efficient modulation techniques can be utilized. In this study an energy-efficient radio-over-fiber media access control protocol using the unlicensed 60-GHz millimeter-wave (mm-wave) band is proposed. The protocol can be best described as an algorithm that generates an isometric distribution of the available frequency-time resources and services the slave motes in monochromatic groups. The master mote builds a frequency-time two-dimensional grid that organizes the chronological service order of this FD-TDMA hybrid protocol. This mechanism provides a collision-free environment in which the sensors can achieve energy independence, also referred as self-sustainability in this work, which is an important feature in BANs. Results show that the proposed protocol successfully manages the BANs in a collision-free and energy self-sustainable manner.

Energy-efficient process-stacking multiplexing access for 60-GHz mm-wave wireless personal area networks

Millimeter-wave technology shows high potential for future wireless personal area networks, reaching over 1 Gbps transmissions using simple modulation techniques. Current specifications consider dividing the spectrum into effortlessly separable spectrum ranges. These low requirements open a research area in time and space multiplexing techniques for millimeter-waves. In this work a process-stacking multiplexing access algorithm is designed for single channel operation. The concept is intuitive, but its implementation is not trivial. The key to stacking single channel events is to operate while simultaneously obtaining and handling a-posteriori time-frame information of scheduled events. This information is used to shift a global time pointer that the wireless access point manages and uses to synchronize all serviced nodes. The performance of the proposed multiplexing access technique is lower bounded by the performance of legacy TDMA and can significantly improve the effective throughput. Work is validated by simulation results.

A novel lightwave device integration and coupling process for optical interconnects

Optical interconnects technology is considered by many researchers and system engineers as the next paradigm shift in data transport technology within a shelf of line cards or data processing boards. A continuing challenge over the past ten years has been the integration process of the laser, detector and waveguide. A major difficulty of this integration process is the optical alignment of these three components which is exacerbated by the fact that both a VCSEL and a standard PIN PD are surface emitting and surface viewing devices, respectively, while waveguides are generally fabricated parallel to the surface of the substrate. Power losses occur for different reasons in the electrical and optical domain. Power losses in the electrical domain are mainly due to the distance traveled, while the power loss in the optical domain is mostly due to light guiding (reflecting, bending, etc.). Choosing an architecture that benefits of the metal mediums advantages and the optical mediums advantages will yield a better channel. In the proposed approach the VCSEL and PIN PD are side-mounted on a sub-anchor board so that the light emission and viewing directions are both in the plane of the substrate. A liquid, photo-definable monomer is placed between the two O/E components and forms a monomer-component interface. Polymerization of the monomer film between VCSEL and PIN PD is initiated with a stripe of UV light defined by a glass mask. By inserting a small distance in the electrical domain such that the light emission, light viewing and waveguide are in the same plane eliminates the need for 45° mirrors, or alternate bending methods, and reduces the overall loss of the optical channel. In addition, the process is simple and inexpensive, making it appealing to access (and other mass produced) networking products for home and in-building communications systems. We have designed, integrated and tested prototype devices using this process. Preliminary experimental results show an average coupling efficiency of 20% and crosstalk of ≪ 27 dB.

Broadband Data Transport Protocol Designed for Ethernet Services in Metro Ethernet Networks

The metro Ethernet network (MEN) expands the advantages of Ethernet to cover areas wider than LAN. Ethernet Services were created to provide multiple services to this carrier-grade network that is rapidly growing popularity in North America [21], Europe [22], and Asia [23]. Techniques to police the network layer for MENs are very mature; but the transport layer relies on different flavors of TCP that do not get the most of Ethernet services. We propose a transport layer protocol that can replace previous versions of TCP to better suit metro Ethernet service policies, such as those established for specified service level agreements (SLAs). Ethernet services traffic and performance parameters include committed information rate (CIR), excess information rate (EIR), and guaranteed packet loss rate. The purpose of this transport protocol is to integrate these parameters, which are applied at the networking layer, into the proposed transport protocol to make a smarter controller.

Short-reach flexible optical interconnection using embedded edge- emitting lasers and edge-viewing detectors

We proposed a novel optical coupling technology for short-reach interconnection (<10m) on flexible polymer waveguides. In order to decrease time and cost of fabrication and assembly, edge-emitting lasers and edge-viewing photodetectors are embedded directly into flexible polymer waveguide in a parallel lithography process. This avoids lenses or angle-reflected components, such as 45° mirrors or volume gratings, which are widely used for VCSEL coupling. Multi-channel optical interconnection can be implemented by passive alignment in a one-time optical lithography process, and no additional expensive components are needed to achieve high coupling efficiency.