Dynamic Switch Migration in Distributed Software-Defined Networks to Achieve Controller Load Balance

© 1983-2012 IEEE. Multiple distributed controllers have been used in software-defined networks (SDNs) to improve scalability and reliability, where each controller manages one static partition of the network. In this paper, we show that dynamic mapping between switches and controllers can improve efficiency in managing traffic load variations. In particular, ...

Adiabatic mode converters for silicon photonics: Power and polarization broadband manipulators

Broadband, low-loss, and fabrication-tolerant photonic passives are of paramount importance in any photonic integrated circuit (PIC). Among others, the adiabatic couplers can have those merits premised on their one-to-one mode transformation characteristics. These devices are usually designed comprising linear waveguide tapers and have typical lengths of 1 mm, in order ...

Measurements of Beamswitching Gains and Fade Dynamics for 28 GHz Indoor Static Links in the Presence of Pedestrian Traffic

We measured channel dynamics for fixed wireless indoor channels at 28 GHz. We characterize pedestrian-induced fades in open indoor spaces and the effectiveness of beamswitching to mitigate them. We find that fades of the dominant propagation path may be as deep as 9 dB at the 90th percentile and that ...

High-performance balun for a dual-polarised dipole antenna

© The Institution of Engineering and Technology 2018 This study proposes a detailed analysis on the operation of a high-performance balun for a dual-polarised dipole antenna. The main feature of this balun is to transform a coaxial feed into a differential feed which can enable very high performance for dual-polarised ...

High-Performance Balun for a Dual-Polarized Dipole Antenna

This paper proposes a detailed analysis on the operation of a high-performance balun for a dual-polarized dipole antenna. The main feature of this balun is to transform a coaxial feed into a differential feed which can enable very high performance for dual-polarized configurations. First, we identify the key factors that ...

The Effects of Housing Environments on the Performance of Activity-Recognition Systems Using Wi-Fi Channel State Information - An Exploratory Study

Recently, device-free human activity monitoring systems using commercial WiFi devices have demonstrated a great potential to support smart home environments. These systems exploit Channel State Information (CSI), which represents how human activity-based environmental changes affect the WiFi signals propagating through physical space. However, given that WiFi signals either penentrate through ...

Performance Evaluation of an Adaptive Self-Organizing Frequency Reuse Approach for OFDMA Downlink

Orthogonal frequency division multiple access (OFDMA) is extensively utilized for the downlink of cellular systems such as long term evolution (LTE) and LTE Advanced (LTE-A). In OFDMA cellular networks, orthogonal resource blocks (RBs) can be used within each cell. However, the available resources are rare and so those resources have ...

Uplink Pilot Allocation for Multi-Cell Massive MIMO Systems

Pilot contamination due to the pilot reuse in adjacent cells is a very serious problem in massive multi-input multiple-output (MIMO) system. Therefore, the pilot allocation is significant for improving the performance of the system. In this paper, we formulate the pilot allocation optimization problem for maximizing uplink sum rate of ...

Transparent Tx and Rx waveform processing for 5G new radio mobile communications

Several different waveform processing techniques have been studied and proposed for the 5G new radio (NR) physical layer, to support new mixed numerology and asynchronous services. The evaluation and comparison of these different techniques is commonly based on matched waveform processing in the transmitter and receiver units. In this article, ...

Investigating the polarization of an omni-directional patch antenna

The ever-present need for higher data rates in telecom networks has a profound effect on what is required from the ideal antenna. In Ultra Dense Networks (UDN), for example, the challenge is to find an omnidirectional, yet orthogonally polarized, antenna of reasonable size. For this purpose, a new antenna type, ...

Wavelength-stable burst-mode laser for next-generation PONs

We developed a novel wavelength-stable burst-mode (BM) laser based on a multi-electrode distributed-feedback (DFB) laser. Our main use-case for the multi-electrode laser (MEL) is a time- and wavelength-division multiplexed passive optical network (TWDM-PON) (NG-PON2), but the wavelength-stable BM laser might also enable future coherent TDM-PON systems and high-rate PON systems ...

Mining competition in a multi-cryptocurrency ecosystem at the network edge: A congestion game approach

Copyright is held by author/owner(s). We model the competition over several blockchains characterizing multiple cryptocurrencies as a non-cooperative game. Then, we specialize our results to two instances of the general game, showing properties of the Nash equilibrium. In particular, leveraging results about congestion games, we establish the existence of pure ...

Communication Aspects of a Modified Cooperative Adaptive Cruise Control Algorithm

This paper investigates the ability of modified Cooperative Adaptive Cruise Control to support high-density car platooning. We first use a simplistic communication model to study the impact of actuation lag, message periodicity, and communication delay on the minimum feasible inter-car spacing. We then use a detailed IEEE 802.11p simulation model ...

Security Witnesses for Compiler Transformations

Compiler optimizations can be correct and yet be insecure. Program changes made during optimization may weaken security guarantees -- for instance, by introducing new ways to leak secret data. This work presents a methodology for ensuring that security properties are preserved during compilation. Properties are expressed as automata operating over ...

Scaling of random walk betweenness in networks

We study the betweenness centrality (BC) of vertices of a graph using random walk paths. Random walk BC (RWBC) provides an alternative measure to the shortest path centrality of each vertex in a graph as it aggregates contributions from possibly all vertex-pairs in the graph and not just from those ...

Precoding and Detection for Broadband Single Carrier Terahertz Massive MIMO Systems Using LSQR Algorithm

The terahertz (THz) communication utilizes the frequency spectrum above 300 GHz and is widely considered as a promising solution to the future high-speed shortrange wireless communication beyond millimeter wave (mmWave) communication. While providing tens of gigahertz bandwidth, it is subjected to high propagation path loss, intersymbol and inter-user interferences. The ...

The paradigm-shift of social spambots: Evidence, theories, and tools for the arms race

  • Cresci S.
  • Petrocchi M.
  • Pietro R.
  • Spognardi A.
  • Tesconi M.

© 2017 International World Wide Web Conference Committee (IW3C2), published under Creative Commons CC BY 4.0 License. Recent studies in social media spam and automation provide anecdotal argumentation of the rise of a new generation of spambots, so-called social spambots. Here, for the first time, we extensively study this novel ...

Automated fiber type identification in SDN-enabled optical networks

We correlate accumulated dispersions measured in coherent receivers to autonomously identify fiber types in a 41-link network without traffic interruption. We achieve 99.66% identification level with only 100 uniformly distributed light paths, even with a 400 ps/nm measurement uncertainty

How 64 GBaud optical carriers maximize the capacity in core elastic WDM networks with fewer transponders per Gb/s

Following the extensive investigations of the research community throughout the last 5 years regarding the transmission performance when roughly doubling the channel symbol rate in WDM systems from generic 32 GBaud to more than 60 GBaud, this evolution is about to become a reality in the field by the next ...

Pilot Allocation for Computationally Efficient Non-Iterative Estimation of Phase Noise in OFDM

This paper proposes a pilot subcarrier allocation approach for OFDM waveforms, which enables construction of phase-noise estimate with high efficiency and low overhead in non-iterative manner. The complexity and the performance of the overall phase-noise suppression algorithm together with the proposed pilot allocation approach are evaluated against a reference algorithm. ...