Seyed Mahdi Darroudi

The digital transformation driven by Industry 4.0 relies on networks that support diverse traffic types with strict deterministic end-to-end latency and mobility requirements. To meet these requirements, future industrial automation networks will use time-sensitive networking, integrating 5G as wireless access points to connect production lines with time-sensitive networking bridges and the enterprise edge cloud. However, achieving deterministic end-to-end latency remains a challenge, particularly due to the variable packet transmission delay introduced by the 5G system. While time-sensitive networking bridges typically operate with latencies in the range of hundreds of microseconds, 5 G systems may experience delays ranging from a few to several hundred milliseconds. This paper investigates the potential of configuring the 5 G time division duplex pattern to minimize packet transmission delay in industrial environments. Through empirical measurements using a commercial 5G system, we evaluate different TDD configurations under varying traffic loads, packet sizes and full buffer status report activation. Based on our findings, we provide practical configuration recommendations for satisfying requirements in industrial automation, helping private network providers increase the adoption of 5 G.

The integration of private fifth-generation (5G) networks with standardized publish-subscribe (PubSub) communication models offers clear benefits for Industry 4.0 applications. While PubSub models ensure vendor-neutral interoperability, backward compatibility, and mature information modeling, the use of 5G non-public networks (NPN) provides dedicated coverage, exclusive capacity, intrinsic controllability, and customized service and operation. In addition, the combination of PubSub protocols and 5G provides a complete communication stack for industrial automation, where PubSub protocols operate on higher OSI layers, and 5G operates on lower layers. However, the practical implications of the integration of PubSub models with 5G systems remain largely unaddressed in the existing literature. To the best of the authors' knowledge, this paper presents the first empirical evaluation of the integration of private 5G with a PubSub protocol, namely open platform communication unified architecture (OPC-UA), in a real production environment. The proposed solution for 5G and OPC-UA integration relies on layer 2 (L2) connectivity over a virtual extensible local area network (VXLAN) tunnel. Evaluation results demonstrate the feasibility of such integration in the context of a soft real-time additive manufacturing (AM) use case for laser metal deposition (LMD)-based manufacturing.

The 5th generation of the cellular network (5G) provides less latency, higher throughput, more cell density, more efficient QoS management, among other benefits [1]. The research community is actively working on the integration of private 5G network into the industrial sector, recognizing 5G as enabler of the industry 4.0 [2]. Being complement with industrial network protocols, or being complement with prior industrial network technologies, is the challenge of exploiting the 5G networks in industry. A big step forward to unlock the deployment of private 5G networks in industrial environment, especially in factories employing mobile robots and enforcing a high level of automation, is the integration between 5G and Time Sensitive Networks (TSN). This paper investigates different approaches of integrating 5G and TSN networks and identifies 5G network features that need to be employed to satisfy TSN network requirements. A Proof of concept has been deployed over a testbed using Amarisoft Radio Access Network (RAN) and core as the private 5G network stack, where we highlight how 5G features can effectively satisfy TSN requirements.

Bluetooth Low Energy (BLE) has become a popular Internet of Things (IoT) technology. However, it was originally designed to only support the star topology. This PhD thesis investigates and evaluates different Bluetooth Low Energy (BLE) mesh network approaches, including existing ones (such as the Bluetooth Mesh standard), and our own solution for IPv6-based BLE mesh networking (6BLEMesh). The thesis comprises 6 main contributions: 1.- A comprehensive survey on existing BLE mesh networking proposals and a taxonomy for BLE mesh network solutions. 2.- An energy consumption model for Bluetooth Mesh. The model allows to predict useful performance parameters, such as device average current consumption, device lifetime and energy efficiency, considering the impact of the most relevant Bluetooth Mesh parameters, i.e. PollTimeout and ReceiveWindow, as well as application parameters (e.g. the data interval for a sensor that periodically reports its readings). 3.- A new proposed IPv6-based BLE mesh networking IETF standard (in progress), called 6BLEMesh. After defining the characteristics and properties of 6BLEMesh, we evaluated it in terms of connectivity, latency, RTT, and energy consumption. 4.- For the connectivity evaluation of 6BLEMesh, we developed an analytical model that takes a set of network and scenario characteristics as inputs, and provides two main results: i) the probability of no isolation of a node, and ii) the k-connectivity of the considered network. We validated the model by simulation. 5.- An implementation, and an experimental evaluation, of 6BLEMesh. We built a three-node testbed consisting of all node types (i.e. 6LN, 6LR and 6LBR). We used three different popular commercial hardware platforms. We evaluated a number of performance parameters on the testbed, related with latency and energy consumption. Next, we characterized the current consumption patterns of the complete life cycle for different node types in the three-node testbed. We also evaluated the energy performance of a 6LN on three different platforms. We presented a 6LN current consumption model for different connInterval settings. To this end, we experimentally characterized each current consumption state in terms of its duration time and average current consumption value. We illustrated the impact of connInterval on energy performance. 6.- A comparison between Bluetooth Mesh and 6BLEMesh, in terms of protocol stack, protocol encapsulation overhead, end-toend latency, energy consumption, message transmission count, end-to-end reliability, variable topology robustness and Internet connectivity. Bluetooth Mesh and 6BLEMesh offer fundamentally different BLE mesh networking solutions. Their performance depends significantly on their parameter configuration. Nevertheless, the following conclusions can be obtained. Bluetooth Mesh exhibits slightly greater protocol encapsulation overhead than 6BLEmesh. Both Bluetooth Mesh and 6BLEMesh offer flexibility to configure per-hop latency. For a given latency target, 6BLEMesh offers lower energy consumption. In terms of message transmission count, both solutions may offer relatively similar performance for small networks; however, BLEMesh scales better with network size and density. 6BLEMesh approaches ideal packet delivery probability in the presence of bit errors for most parameter settings (at the expense of latency increase), whereas Bluetooth Mesh requires path diversity to achieve similar performance. Bluetooth Mesh does not suffer the connectivity gaps experimented by 6BLEMesh due to topology changes. Finally, 6BLEMesh naturally supports IP-based Internet connectivity, whereas Bluetooth Mesh requires a protocol translation gateway. Bluetooth Low Energy (BLE) ha esdevingut una tecnologia popular per a Internet of Things (loT). Ara bé, va ser originalment dissenyada per suportar només la topologia en estrella. Aquesta tesi doctoral investiga i avalua diferents alternatives de xarxa mesh BLE, incloent alternatives existents (com l'estandard Bluetooth Mesh), i la nostra propia solució basada en IPv6, 6BLEMesh. Aquesta tesi comprén 6 contribucions·principals: 1.- Una revisió exhaustiva de l'estat de l'art i una taxonomia de les xarxes mesh BLE. 2.- Un model de consum d'energia per Bluetooth Mesh. El model permet predir parametres de rendiment útils, tals com consum de corrent, temps de vida del dispositiu i eficiéncia energética, considerant !'impacte deis principals parametres de Bluetooth Mesh (PollTimeout i ReceiveWindow) i a nivell d'aplicació. 3.- Un nou estandard (en progrés) anomenat 6BLEMesh. Després de definir les característiques de 6BLEMesh, aquesta solució ha estat avaluada en termes de connectivitat, laténcia, RTT i consum d'energia. 4.- Per a l'avaluació de connectivitat de 6BLEMesh, hem desenvolupat un model analític que proporciona dos resultats principals: i) probabilitat de no arllament d'un node i ii) k-connectivitat de la xarxa considerada. Hem validat el model mitjani;:ant simulació. .- Una imP.lementació, i una avaluació experimental, de 6BLEMesh. S'ha construrt un testbed de tres nodes, que comprén 5tots els tipus de node principals (6LN, 6LR i 6LBR). S'han usat tres plataformes hardware diferents. S'han avaluat diversos parametres de rendiment en el testbed, relacionats amb laténcia i consum d'energia. A continuació, s'ha caracteritzat els patrons de consum de corren! d'un ciclde de vida complet per als diferents tipus de nodes en el testbed. També s'han avaluat les prestacions d'energia d'un 6LN en tres plataformes diferents. S'ha presenta! un model de consum de corren! d'un 6LN per a diferents valors de connlnterval. Per aquest fi, s'ha caracteritzat emplricament cada estat de consum de corrent en termes de la seva durada i consum de corrent. 6.- Una comparativa entre Bluetooth Mesh i 6BLEMesh, en termes de pila de protocols,...

Beyond 5G networks will not only present an evolution of the current 5G standards, but they will also provision a path for increased convergence with other Radio Access Technologies (RATs). The Wi-Fi Alliance and 3GPP through their standards releases have presented a lucrative inter-working opportunity for the same. Such a convergence will help to enhance the Quality of Experience (QoE) for the users. However, one of the most important challenge towards a more converged scenario is the provision of uniform Quality of Service (QoS) across cellular and Wi-Fi RATs. Hence in this paper, to the best of our knowledge, we propose the first attempt in literature to homogenize Wi-Fi and 5G QoS. Specifically, a method is presented to map Wi-Fi QoS parameters to 5G QoS Identifiers (5QI). The presented results, which show a clear possibility of the 5G and Wi-Fi QoS harmonization, have been obtained via a real testbed setup.

Most Internet of Things (IoT) communication technologies rely on terrestrial network infrastructure. When such infrastructure is not available or does not provide sufficient coverage, satellite communication offers an alternative IoT connectivity solution. Satellite-enabled IoT devices are typically powered by a limited energy source. However, as of this writing, and to our best knowledge, the energy performance of satellite IoT technology has not been investigated. In this paper, we model and evaluate the energy performance of Iridium satellite technology for IoT devices. Our work is based on real hardware measurements. We provide average current consumption, device lifetime, and energy cost of data delivery results as a function of different parameters. Results show, among others, that an Iridium-enabled IoT device, running on a 2400 mAh battery and sending a 100-byte message every 100 min, may achieve a lifetime of 0.95 years. However, Iridium device energy performance decreases significantly with message rate.

Bluetooth Low Energy (BLE) has become a major wireless technology for the Internet of Things (IoT). Recent efforts of academia, industry and standards development organizations have focused on creating BLE mesh network solutions. 6BLEMesh is a specification being developed by the IETF that defines an IPv6-oriented approach for BLE mesh networking. In this paper, we perform an experimental evaluation of 6BLEMesh, based on a real implementation. We evaluate latency, round trip time (RTT) and energy consumption. For the latter, we model the device current consumption, we determine the energy efficiency of communication, and we obtain the theoretical device lifetime (for battery-operated devices), for three different hardware platforms. Under the assumptions in our study (including a simple 235 mAh battery, and periodic data transmission), the maximum, asymptotic, device lifetime is 573 days, whereas battery-operated router devices can also achieve 3-digit lifetimes (in days) in many scenarios. Our results also illustrate the impact on performance of BLE-level and application-level parameter settings, adaptation layer mechanisms such as IPv6 header compression, and device hardware characteristics.

Bluetooth Low Energy (BLE) mesh networking is an emerging technology domain that promises an important role in the Internet of Things. Significant market opportunities for BLE mesh networking have motivated the recent development of two different BLE mesh networking standards, Bluetooth Mesh and 6BLEMesh, produced by the Bluetooth SIG and IETF, respectively. These two standards follow different technical approaches. In this article, we present the main features of Bluetooth Mesh and 6BLEMesh, and investigate their performance characteristics and trade-offs.

The recent publication of the Bluetooth Mesh standard is a remarkable milestone in the evolution of Bluetooth Low Energy (BLE). As a new technology in the Internet of Things (IoT) market, it is crucial to investigate the performance of Bluetooth Mesh. However, while a fundamental feature of Bluetooth Mesh is its suitability for energy-constrained devices, this aspect has not yet been properly considered in the literature. In this paper, we model the current consumption, lifetime and energy cost per delivered bit of a battery-operated Bluetooth Mesh sensor node. The model is based on measurements performed on a real hardware platform. Evaluation results quantify the impact of crucial Bluetooth Mesh parameters. Among others, we have found that a sensor device running on a simple 235 mAh battery, and sending a data message every 10 s, can achieve a lifetime of up to 15.6 months, whereas the asymptotic lifetime is 21.4 months.

Bluetooth Low Energy (BLE) has become one of the most popular low-power wireless technologies. While BLE was originally designed for star topology networks only, recent developments have focused on enabling mesh network topology support for BLE. An emerging category of BLE mesh network initiatives is based on routing data units over BLE data channels. This letter investigates the fundamental connectivity parameters of data-channel-based BLE mesh networks, such as the probability of no isolation of a node and network K-connectivity. We provide an analytical model for both parameters which is validated by means of extensive simulations.