The expected growth in the number of connected devices, together with the spectrum crunch in overcrowded radio bands, motivates the exploration of complementary wireless technologies. Optical Wireless Communication (OWC), including visible light systems, provides a vast unlicensed spectrum but introduces unique networking challenges: strong directionality, line-of-sight requirements, sensitivity to shadowing, and fast link intermittency due to mobility. This paper presents PARC (Proactive and Adaptive Routing Control), a proactive routing protocol designed specifically for light-based ad hoc networks (LANETs). PARC combines proactive topology dissemination with link-quality-aware route selection and adaptive control mechanisms. We evaluate PARC in ns-3 OWC scenarios ranging from static baselines to highly dynamic and high-density settings, including an additional extended stress-test with simultaneous mobility and full traffic load. Overall, PARC sustains significantly higher packet delivery and throughput than the OLSR reference protocol under challenging conditions.

The rapid growth of wireless devices highlights the competition for limited radio frequency spectrum. Optical Wireless Communication (OWC) emerges as a promising complementary technology, but it requires specialized routing solutions. Existing protocols, primarily designed for radio frequency, often struggle with the unique challenges of OWC. This paper introduces and evaluates PARC (Proactive and Adaptive Routing Control), a novel routing protocol that combines proactive control with adaptive mechanisms tailored to dynamic optical channels. Through extensive simulations in ultra-high-density and high-mobility scenarios, we compare PARC to the reference protocol OLSR. Our results demonstrate that PARC significantly outperforms OLSR, with an 85 % higher data throughput for PARC (139.88 kbps vs. 75.64 kbps). PARC's architecture offers a robust, efficient, and scalable solution for future wireless optical networks, effectively overcoming the limitations of traditional proactive protocols in dynamic environments.

O Sistema de Nomes de Domínio (DNS) é fundamental para a Internet, traduzindo nomes de domínio em endereços IP. No entanto, a maioria dos resolvedores modernos opera em espaço de usuário, o que gera alta latência devido à travessia da pilha de rede e trocas de contexto com o kernel. Soluções que evitam essa travessia geralmente dependem de espera ocupada, desperdiçando recursos sob baixa carga. Este artigo apresenta o AtesN-DS, um resolvedor DNS recursivo híbrido baseado em eBPF, que opera no kernel antes da pilha de rede, no gancho XDP, reduzindo a latência com uso eficiente de CPU. O AtesN-DS resolve nomes e gerencia cache diretamente no kernel. Consultas pendentes são armazenadas em mapas eBPF, e, à medida que esses mapas se aproximam da capacidade máxima, novas consultas são delegadas ao resolvedor em espaço de usuário. Tarefas mais complexas, como renovação proativa de cache e prevenção de erros via consultas redundantes, são encaminhadas ao espaço de usuário via ring buffers. Experimentos mostram que o AtesN-DS reduz em até 51% a latência e aumenta a vazão em até 213%, comparado com soluções como o hyDNS, mantendo o uso de CPU abaixo de 2%.

Este estudo propõe o protocolo Dual-Radio-Dual-Slotframe (DRDS), uma nova abordagem para melhorar o desempenho de redes de sensores sem fio com rádio duplo. Baseado no Time Slotted Channel Hopping (TSCH) na camada MAC, o protocolo utiliza uma alocação combinada de slotframes para dois rádios. Implementado e avaliado no Contiki-NG e Cooja, o DRDS demonstrou superioridade em termos de vazão de pacotes em todos os cenários analisados, destacando-se como uma solução promissora para otimizar redes IoT.

The 6G wireless networks are already being studied and their main novelties are beginning to emerge. The 6G network promises 100% network coverage in every area, including wilderness areas such as the ocean, desert, or remote areas, as it will be a fully 3D network, i.e., it will integrate space, air, and terrestrial networks. Also, with all these types of devices, the complexity of 6G networks increases, and Artificial Intelligence (AI) techniques will be mandatory for all the 6G’s potential data and parameters. Hence, a Space-Air-Ground Integrated Network (SAGIN) is a potential alternative to enable all the network coverage as drones and satellites can cover large areas and fill possible network coverage gaps. The 6G network coverage also includes post-disaster regions with no network infrastructure and no network coverage, making SAGIN very suitable for them. Thus, in this work, we expand CAIN, a post-disaster 6G routing protocol, so it can also be used in SAGIN scenarios, increasing even more network coverage. With drones as relays, SAGIN-CAIN routes the CAIN’s Cluster Head’s messages until it reaches a satellite.

NFV and SDN enable flexibility and programmability at the data plane. In addition, offloading packet processing to a hardware saves processing resources to compute other workloads. However, fulfilling requirements such as high throughput and low latency with a flexible and programmable data plane is challenging. This paper introduces eBPFlow, a platform for seamlessly accelerating network computation. It builds upon eBPF. eBPFlow combines flexibility and programmability in software with high performance using an FPGA. We implemented our system on the NetFPGA SUME, performing tests on a physical testbed. We built a range of NFs. Our results show that the eBPFlow supports offloading of NFs with throughput at the line rate, latency between $20~\mu \text{s}$ and $40~\mu \text{s}$ , communication with host, and consumption of 22 W. Moreover, eBPFlow processes 12.05 Mpps more than the kernel. eBPFlow has a throughput of 2.59 Gbps higher than the hXDP, a system similar to eBPFlow.

Optical Wireless Communication (OWC) proved to be one of the complementary technologies to radio frequency, which can help solve the crowded spectrum problem. Furthermore, new applications such as the Internet of Things and Wireless Sensor Networks can benefit from OWC. With the increase in connected devices, using the channel efficiently becomes even more necessary. This paper presents a model for the OWC channel and develops a method to calculate the OWC channel’s efficiency. The model was validated experimentally with the OpenVLC 1.1 platform. With it, it is possible to determine the ideal packet size to maximize the channel’s efficiency. Using Pearson’s correlation method between model data and experimental values, we obtained up to 99.8% correlation.

Due to the current challenges of wireless communications, optical wireless communications, like visible light communication (VLC), have become very popular in the last decade for local area networks. However, current VLC systems focus mainly on one-hop direct transmissions, ignoring that many networking applications require multicast communications. In this sense, we propose MCAST-VLC, a fully functional cross-layer dynamic multicast scheme over a dynamic routing protocol for VLC. MCAST-VLC considers the particular characteristics of the VLC as the need for group management, traffic isolation, a challenging multi-hop route discovery protocol, and a complex cross-layer VLC mechanism to maintain the proper system state. We evaluate our protocol following close real indoor VLC scenarios, previously discussed in the literature, where a light source in a room streams data to a few other VLC devices, and we extend our results numerically. Our results show that MCAST-VLC can handle considerably more network flows than a unicast VLC system under a negligible overhead.

This paper presents the novel routing protocol called Underwater Greedy Geographic Routing by Network Embedding (UW-GRE) for underwater wireless networks. Geographic routing is a promising network routing protocol strategy for wireless networks because it is stateless. However, this routing strategy faces various problems in the underwater environment. This is caused by some challenging characteristics of this environment, such as its 3D nature and the no propagation of GPS signal due to high radio frequency signal attenuation. Accurate localization, void regions, and guaranteed delivery are then some of the problems faced by this routing strategy in this environment. In this paper, we solve those problems efficiently by using geographic routing over virtual coordinates obtained through a network embedding in an n-dimensional (n ≥ 2) Euclidean virtual space. By properly embedding the network in this virtual Euclidean space, no geographic information is needed. We implemented the protocol on ns-3. Our results show that, when compared to a conventional geographic routing protocol with perfect localization information, our protocol improves the number of transmissions and energy consumption by up to or higher than 30%, end-to-end delay by up to 28%, while achieving similar network throughput.

Among several link-layer protocols, Time-Slotted Channel Hopping (TSCH), defined in the IEEE 802.15.4e standard, offer a good performance improving reliability and throughput for wireless sensor network using in the best way two parameters: time and frequency. Many works in the current literature present scheduling schemes for the protocol. In this scenario, our work is among a small group that aims to explore the improvements of the protocol by exploiting different techniques over the transport layer of the network protocol. Channels with wider bandwidth can improve network performance by increasing the throughput and improving packet delivery. Therefore, this paper proposes a scheduling algorithm to dynamically allocate channels with variable bandwidth to improve the overall throughput and packet delivery. The scheduling and channel allocation happen using the conflict mapping method to identify links in congestion and schedule them. This work proposes a procedure for allocating channels with bandwidth proportional to the demand for packets per link. We implemented the algorithm in the Contiki-NG platform and evaluated the result through simulations. Results show improved time slot allocation, packet delivery ratio, and throughput. Our experiments show that VariBan achieves a throughput of over 99% and improves Packet Delivery Ratio by over 50% in all three scenarios compared to the state-of-the-art algorithm.

Aiming to increase throughput in Wireless Networks, such as in Wireless Sensor Network and the Internet of Things, platforms emerged in which devices have two radios, and also data transfer protocols that prioritize maximum throughput and energy efficiency, using two different paths simultaneously. The usage of dual radios allowed simultaneous transmissions between wireless devices, which, besides increasing network throughput, can also improve network stability, delivery rate, transmission cost, and energy consumption per transmitted byte. However, one path may be much longer than the other, causing high latency. First, in this work, we present the problem formulation to find two disjoint paths with the same parity size for platforms with two heterogeneous radios to reach the network maximum flow, while also minimizing the longest path, which reduces latency. Second, we show that the problem is NP-Complete. Next, we present a solution based on integer linear programming. Moreover, we tested the solution on almost 5,700 instances obtained from an actual testbed and the results show a reduction in latency while maintaining the high throughput.

More devices are being introduced to the cellular network every day, and it is time to think about how the next generation will deal with them. The 6G will bring new ways to think about how to share information and will not rely just on communication with a fixed Base Station (BS). A post-disaster scenario may damage the network infrastructure; the devices need to create an ad-hoc network to communicate in this situation. The ad-hoc network must achieve some of the 6G’s requirements, such as communication frequency, data rate, and latency, to communicate with the 6G networks when available. The increase in the frequency used to achieve such data rate has the downside of decreasing the signal range, i.e., for two nodes to communicate, they must be closer to each other. Academia is developing alternatives to increase the network coverage area, allowing devices to further the ad-hoc Access Point (AP) to overcome this drawback. Thus, with this work, we propose CAIN, an 6G routing protocol that uses Artificial Intelligence (AI) techniques to increase the network coverage area. Depending on the node’s connectivity to an AP, i.e., if the node is connected to an AP or not, CAIN uses different messages to make nodes further the AP to communicate with it, increasing the network coverage area. Hence, if there is no connected node to an AP, it chooses a neighbor with a connection to one to forward the message. Also, if there is no connected neighbor to an AP, the node chooses a neighbor to flood the message until it reaches an AP. To improve its performance, we enhance CAIN with AI techniques, such as Reinforcement Learning (RL), Federated Learning (FL), and Deep Neural Network (DNN). These techniques allow the node to make a better neighbor choice and increase the network coverage area even more. To the best of our knowledge, this is the first work that proposes a routing protocol for the 6G scenario that uses RL techniques with FL and DNN to increase the network coverage. With these characteristics, CAIN makes devices further the APs to communicate with it using less energy and storage resources, producing less delay compared to other protocols.

The minmax regret shortest path arborescence (M-SPA) problem under interval uncertainty is a robust counterpart of the shortest path (SP) arborescence problem, where arc costs are modeled as intervals of possible values. This problem finds applications in the design of topologies for low-power wireless personal area networks. The previous work presented a mixed-integer linear programming formulation and heuristics for this problem. In this paper, we propose a new heuristic for M-SPA, called the fix-and-optimize through heuristic decomposition (FO-HD). It consists of two steps. The first step solves multiple instances of the minmax regret SP problem under interval uncertainty, while the second step combines their solutions into an arborescence. As far as we know, this is the first work in the literature to apply the fix-and-optimize metaheuristic to minmax regret problems. We also show that a lower bound for the optimal solution of M-SPA can be computed from the first step of FO-HD. This lower bound allows us to show that the maximum average optimality gap of this heuristic was 0.2% among all classical and novel instances used in the computational experiments.

Atualmente, a demanda por comunicação por redes sem fio tem crescido exponencialmente. Contudo, as tecnologias de comunicação sem fio disponíveis hoje podem não ser suficientes para acompanhar a crescente demanda por banda. Nesse contexto, a Comunicação por Luz Visível (VLC) consiste em uma possibilidade válida e promissora, tendo em vista a alta taxa de transferência de dados, a utilização de uma infraestrutura de iluminação já amplamente difundida na atualidade, além de um largo espectro disponível e não reservado para o uso. Logo, este trabalho tem como objetivo apresentar uma implementação do protocolo de rede Multicast na Comunicação Por Luz Visível.

A comunicação subaquática sem fio (UWC) é de grande interesse para aplicações militares, industriais e para a comunidade científica, pois desempenha um papel importante, como por exemplo, na vigilância tática e no monitoramento da poluição da água. A UWC pode ser realizada usando ondas acústicas, de radiofrequência (RF) e ópticas. Em contraste com as ondas acústicas e de RF, a comunicação óptica sem fio subaquática (UWOC) pode suportar taxas de dados mais altas com baixos níveis de latência. Entretanto, as propriedades do canal de água representam desafios significativos para a UWOC, o que exige soluções de rede eficientes. Nesse sentido, este artigo investiga o desempenho de um sistema UWOC com um transmissor no espectro de luz vermelha em um ambiente aquático raso e claro. Foram realizadas avaliações sobre o impacto no desempenho da transmissão causado diodos de laser (LDs) nesse comprimento de onda. Os resultados apresentados mostram o impacto na comunicação causado pelo meio, pela distância entre os nós e pelo tipo de transmissor usado. Além disso, eles demonstram a viabilidade do uso da luz vermelha na comunicação, que atingiu uma taxa de dados máxima de 5,08 kbps com 5 cm de distância entre os nós.

Dual-Radio platforms were proposed to improve the throughput of Wireless Sensor Network applications while conserving energy efficiency. However, current dual-radio protocols do not use all the hardware available. We model this problem as the minimum disjoint parity paths problem. We present the design, implementation and evaluation of SplitPath, a distributed routing protocol that computes two vertex-disjoint paths with the same parity. Unlike previous work on multipath routing, SplitPath is the first protocol to use multiple paths in dual-radio WSNs to achieve maximum throughput. The protocol was evaluated with experiments in the physical world. We compare our proposal with FastForward, the state-of-the-art protocol for dual-radio. Our approach improved the throughput by 60%, and achieved 96% of the maximum theoretical limit.

Underwater wireless acoustic networks (UWANs) take advantage of acoustic communication to enable many distinct applications. The peculiar features of underwater acoustic channels, such as long propagation delay, high bit error rates, and severely limited bandwidth, make the use of medium access control (MAC) solutions designed for terrestrial radio networks inefficient in UWANs. This paper proposes UW-SEEDEX, a MAC protocol for UWANs that employs random time slot schedules, created from seeds, to avoid collisions. After exchanging seeds, nodes can know other's entire schedules, allowing them to then better plan their transmissions. Simulations evaluate how each of UW-SEEDEX's parameter affects its performance in metrics such as end-to-end delay, energy consumption, transmissions per data reception, and reception rate using different test scenarios. Simulations also show that UW-SEEDEX can perform better than other MAC solutions, delivering more messages than protocols such as UW-Aloha and Slotted FAMA and reduced, on average, up to three times the number of transmissions required for each message reception in networks with grid topologies. UW-SEEDEX presented reception rates close to 100 percent, low energy cost, and fewer transmissions per data reception. Our code is available at https://gitlab.com/epmcj/ns-3-dev/-/tree/new-uan-mac-protocols.

The transmission and reception of packets in wireless networks suffer from interference, packet collisions, and bottlenecks that increase latency and reduce network throughput. The high demand for a set of links can turn the network inefficient and even dead. The TSCH networks try to avoid collisions by scheduling channels and time. However, there is still the presence of bottlenecks, and an improvement is required. Channels with wider bandwidth can improve the network in bottleneck regions. Therefore, this paper proposes a scheduling algorithm to dynamically allocate channels with variable bandwidth to reduce bottlenecks and improve network performance. The scheduling and channel allocation happen using the conflict mapping method where congestion is identified. A set of nodes compete for the same communication channel resources and sending time, organizing them to improve the network performance. This work proposes a procedure for allocating channels with bandwidth proportional to the demand for packets per link. We implemented the algorithm in the Contiki-NG platform. Results show a reduction in the slot time duration and improvement in packet delivery.

In the electronic design automation field, many tools focus on obtaining the maximum amount of information about the input to which it is provided in order to determine the best algorithms in each instance. Many of these inputs originate from circuits, and the greater the amount of information that can be gathered about a particular circuit, the more accurately the problems can be addressed. Some of these tools are the Boolean satisfiability (SAT) problem solvers, which, for the most part, receive formulas described in conjunctive normal form (CNF) as input. Unfortunately, the circuits encoding the process of the CNF format destroy much of the information that could have been used to optimize SAT solvers, as part of this information must be recovered to avoid applying generic algorithms in the solution of SAT problems. One of the difficult aspects of retrieving this information corresponds to the matching of clauses to their respective logic gates, as well as which sets of logic gates correlate to a functional block. The present work makes use of subgraph isomorphism algorithms to recover circuits encoded in CNF-DIMACS maximizing the number of clauses handled, at the level of both logic gates and more complex structural blocks, which allows their identification at higher levels of abstraction. For this purpose, a tool named GRCircuit was created which was able to successfully recover all circuits generated as tests, in addition to recovering 100% of the circuits from ISCAS 85 and ITC 99 benchmarks. These results demonstrate that it is possible to recover the circuit's structure and identify functional blocks using only graph algorithms, without backtracking approaches, in addition to prioritizing the number of clauses used instead of the number of logic gates.

Este artigo apresenta o protocolo CodeTSCH, que utiliza a Codificação em Rede (Network Coding) em redes TSCH (Time-Slotted Channel Hoping) para otimizar a entrega de mensagens e diminuir o número de slots utilizados. Esse processo possibilita que duas mensagens sejam combinadas em apenas um pacote, possibilitando uma menor quantidade de mensagens circulando na rede, bem como uma maior robustez à perda de mensagens. Comparou-se o CodeTSCH em simulações com o protocolo estado da arte TSCH. Os resultados demonstram que o CodeTSCH permite uma entrega das mensagens com melhoria de até 50% em comparação com o protocolo estado da arte TSCH em redes com perdas de pacotes.