Wireless Local Area Network Technologies as Communication Solutions for Unmanned Surface Vehicles

As the number of research activities and practical deployments of unmanned vehicles has shown a rapid growth, topics related to their communication with operator and external infrastructure became of high importance. As a result a trend of employing IP communication for this purpose is emerging and can be expected to bring significant advantages. However, its employment can be expected to be most effective using broadband communication technologies such as Wireless Local Area Networks (WLANs). To verify the effectiveness of such an approach in a specific case of surface unmanned vehicles, the paper includes an overview of IP-based MAVLink communication advantages and requirements, followed by a laboratory and field-experiment study of selected WLAN technologies, compared to popular narrowband communication solutions. The conclusions confirm the general applicability of IP/WLAN communication for surface unmanned vehicles, providing an overview of their advantages and pointing out deployment requirements.

eSCIFI: An Energy Saving Mechanism for WLANs Based on Machine Learning

As wireless local area networks grow in size to provide access to users, power consumption becomes an important issue. Power savings in a large-scale Wi-Fi network, with low impact to user service, is undoubtedly desired. In this work, we propose and evaluate the eSCIFI energy saving mechanism for Wireless Local Area Networks (WLANs). eSCIFI is an energy saving mechanism that uses machine learning algorithms as occupancy demand estimators. The eSCIFI mechanism is designed to cope with a broader range of WLANs, which includes Wi-Fi networks such as the Fluminense Federal University (UFF) SCIFI network. The eSCIFI can cope with WLANs that cannot acquire data in a real time manner and/or possess a limited CPU power. The eSCIFI design also includes two clustering algorithms, named cSCIFI and cSCIFI+, that help to guarantee the network’s coverage. eSCIFI uses those network clusters and machine learning predictions as input features to an energy state decision algorithm that then decides which Access Points (AP) can be switched off during the day. To evaluate eSCIFI performance, we conducted several trace-driven simulations comparing the eSCIFI mechanism using both clustering algorithms with other energy saving mechanisms found in the literature using the UFF SCIFI network traces. The results showed that eSCIFI mechanism using the cSCIFI+ clustering algorithm achieves the best performance and that it can save up to 64.32% of the UFF SCIFI network energy without affecting the user coverage.

A User Prioritisation Algorithm for Horizontal Handover in Dense WLANs

This paper proposes an algorithm that enhances horizontal handover (HO) in dense wireless local area networks (WLANs), which is implemented in a software-defined wireless networking (SDWN)-based architecture. The algorithm considers the concept of user prioritisation, classifying the WLAN stations (STAs) into two categories representing high and low priorities respectively, and always attempts to guarantee the best quality of experience (QoE) to the high priority users. The architecture that implements the algorithm leverages the flexibility, programmability, and centralised nature of SDWN to efficiently manage the HO process. Moreover, the paper presents a performance evaluation campaign that demonstrates significant achievements against a state-of-the-art solution in terms of the provided QoE, throughput and delay. Finally, we discuss the importance of considering user prioritisation in a HO algorithm for dense WLANs.

Improving Spatial Reuse of Wireless LAN Uplink Using BSS Color and Proximity Information

With the density of wireless networks increasing rapidly, one of the major goals in next-generation wireless LANs (Local Area Networks) is to support a very dense network with a large number of closely deployed APs (Access Points) and crowded users. However, the CSMA (Carrier-Sense Multiple Access)-based medium access control of current wireless network systems suffers from significantly degraded performance when the network becomes dense. Recent WLAN (Wireless Local Area Networks) standards include measures for increasing spatial reuse such as BSS (Basic Service Set) coloring, but the schemes based on BSS coloring such as OBSS/PD (Overlapping BSS/Preamble Detection) have limitations in improving spatial reuse. In this paper, we propose a spatial reuse method for uplink which can utilize BSS color and proximity information to improve the efficiency of carrier sensing and thus spatial reuse. Specifically, through the BSS color and the proximity information, a node receiving a preamble can figure out how far the receiver of the ongoing traffic is located. This information is used to determine whether the node should aggressively start transmitting or defer its transmission to protect the ongoing transmission. Simulation results show that the proposed method outperforms existing methods in terms of throughput and fairness.

UWB Dual-Band-Notched Lanky-Leaf-Shaped Antenna with Loaded Half-Square-Like Slots for Communication System

A novel printed compact single-layer dual-band-notched antenna for the use of ultra-wide band (UWB) is proposed in this paper, and one lanky-leaf-like structure with a coplanar waveguide (CPW) feed is designed as the radiated element for a large operating bandwidth. To realize the dual-band-notched characteristics of microwave access (WiMAX) and wireless local area networks (WLAN), two half-square-like slots are etched on the metallic surface. The fabricated prototype of this proposed antenna has a compact size of 27 × 32 mm2 and operates at 2.8 GHz to 10 GHz, excepting for rejection bands at 3.06–3.83 GHz and 5.05–5.96 GHz. Nearly omnidirectional radiation patterns are obtained in the working band. Furthermore, one conformal design on cylinder and transfer characteristics are made to validate its potential application. These findings indicate that this antenna can be taken as a promising option for use in the UWB communication field.

Virtualization of Programmable Forwarding Planes with P4VBox

Networking virtualization has shown to enable faster service provioning and server as a main driver of innovation, from Software-Defined Networking (SDN) to Network Function Virtualization (NFV) and Local Area Networks (VLAN). Recent investigations began assessing the feasibility of virtualization in Programmable Data Planes (PDP). Despite the progress achieved, much work remains to assess their effectiveness for programmable virtual switches. In a prior work, we introduced P4VBox, an architecture for virtualization of programmable switches written using the P4 language. P4VBox provides the execution of multiple P4 based switch instances running in parallel, with the ability of hot-swapping through full and partial reconfiguration. In this work, we build upon P4VBox to provide novel insights, substantiated by experimental evaluation on a real-world testbed, on the evaluation of the real power of switch virtualization in a NetFPGASUME board, deploying three use cases. We measured resource utilization and performance to observe the behavior of P4VBox when handling large flows. Our results demonstrate that P4VBox incurs a small overhead compared with the canonical NetFPGA reference design. Yet, it increases orders of magnitude considering the existing works.