No full-text available
To read the full-text of this research,
you can request a copy directly from the authors.
On the Use of IEEE 802.11n for Industrial Communications
... There is a large number of physical layer communication technologies to choose from, making it difficult to determine which one would provide the best performance for a given use case in a smart environment [1]. IEEE technology in smart industrial communication networks at its peak performance, in contrast to previous technologies, is not always guaranteed and should not be considered a default answer without confirmation from various types of studies that provide an in-depth investigation of these technologies [2,3]. In other words, determining the best way to employ IEEE technology in industrial communication networks is quite similar to determining the best way to use an older piece of technology. ...
... Three spatial configurations using IEEE 802.11 standards are examined. As can be observed in Figure 10a and Figure 11, both network topologies, BSS and ESS, are able to function in small and medium-sized networks (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20), with 11g, 11e, and 11n technologies providing the highest level of performance. In the first group, where 5 ≥ N > 0, there is a variety of options provided by BSS and ESS. ...
... Three spatial configurations using IEEE 802.11 standards are examined. As can be observed in Figures 10a and 11, both network topologies, BSS and ESS, are able to function in small and medium-sized networks (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20), with 11g, 11e, and 11n technologies providing the highest level of performance. In the first group, where 5 ≥ N > 0, there is a variety of options provided by BSS and ESS. ...
In this research paper, the spatial distributions of five different services—Voice over Internet Protocol (VoIP), Video Conferencing (VC), Hypertext Transfer Protocol (HTTP), and Electronic Mail—are investigated using three different approaches: circular, random, and uniform approaches. The amount of each service varies from one to another. In certain distinct settings, which are collectively referred to as mixed applications, a variety of services are activated and configured at predetermined percentages. These services run simultaneously. Furthermore, this paper has established a new algorithm to assess both the real-time and best-effort services of the various IEEE 802.11 technologies, describing the best networking architecture as either a Basic Service Set (BSS), an Extended Service Set (ESS), or an Independent Basic Service Set (IBSS). Due to this fact, the purpose of our research is to provide the user or client with an analysis that suggests a suitable technology and network configuration without wasting resources on unnecessary technologies or requiring a complete re-setup. In this context, this paper presents a network prioritization framework for enabling smart environments to determine an appropriate WLAN standard or a combination of standards that best supports a specific set of smart network applications in a specified environment. A network QoS modeling technique for smart services has been derived for assessing best-effort HTTP and FTP, and the real-time performance of VoIP and VC services enabled via IEEE 802.11 protocols in order to discover more optimal network architecture. A number of IEEE 802.11 technologies have been ranked by using the proposed network optimization technique with separate case studies for the circular, random, and uniform geographical distributions of smart services. The performance of the proposed framework is validated using a realistic smart environment simulation setting, considering both real-time and best-effort services as case studies with a range of metrics related to smart environments.
... Second, the high data rate of this standard, compared to low-power technologies such as 802. 15.4 and Bluetooth Low Energy (BLE), facilitates the development of applications such as medical monitoring, video streaming, process control, and robotics [5]- [7]. Third, the energy consumption of WiFi stations has been significantly reduced during recent years. ...
... Probe Response(P RBR) < l a t e x i t s h a 1 _ b a s e 6 4 = " V + 6 T Z U u 5 j R A 6 R S d 2 E 2 m X g b x P P j E = " > A A A B 7 n i c b V B N S w M x E J 3 U r 1 q / q h 6 9 B I t Q L 2 V X K n o s 9 e K x F v s B 7 V K y a b Y N z W a X J C u U p T / C i w d F v P p 7 v P l v T N s 9 a O u D g c d 7 M 8 z M 8 2 P B t X G c b 5 T b 2 N z a 3 s n v F v b 2 D w 6 P i s c n b R 0 l i r I W j U S k u j 7 R T H D J W o Y b w b q x Y i T 0 B e v 4 k 7 u 5 3 3 l i S v N I P p p p z L y Q j C Q P O C X G S p 1 y o 1 k f N C 8 H x Z J T c R b A 6 8 T N S A k y N A b F r / 4 w o k n I p K G C a N 1 z n d h 4 K V G G U 8 F m h X 6 i W U z o h I x Y z 1 J J Q q a 9 d H H u D F 9 Y Z Y i D S N m S B i / U 3 x M p C b W e h r 7 t D I k Z 6 1 V v L v 7 n 9 R I T 3 H o p l 3 F i m K T L R U E i s I n w / H c 8 5 I p R I 6 a W E K q 4 v R X T M V G E G p t Q w Y b g r r 6 8 T t p X F b d a u X 6 o l m r 1 L I 4 8 n M E 5 l M G F G 6 j B P T S g B R Q m 8 A y v 8 I Z i 9 I L e 0 c e y N Y e y m V P 4 A / T 5 A / b K j q 4 = < / l a t e x i t > (P RBQ) < l a t e x i t s h a 1 _ b a s e 6 4 = " r D F i Y j S 0 f P P G C 1 s 3 l q 2 J K F M m U v M = " > A A A B 7 n i c b V B N S w M x E J 3 U r 1 q / q h 6 9 B I t Q L 2 V X K n o s 9 e K x F f s B 7 V K y a b Y N z W a X J C u U p T / C i w d F v P p 7 v P l v T N s 9 a O u D g c d 7 M 8 z M 8 2 P B t X G c b 5 T b 2 N z a 3 s n v F v b 2 D w 6 P i s c n b R 0 l i r I W j U S k u j 7 R T H D J W o Y b w b q x Y i T 0 B e v 4 k 7 u 5 3 3 l i S v N I P p p p z L y Q j C Q P O C X G S p 1 y 4 6 E + a F 4 O i i W n 4 i y A 1 4 m b k R J k a A y K X / 1 h R J O Q S U M F 0 b r n O r H x U q I M p 4 L N C v 1 E s 5 j Q C R m x n q W S h E x 7 6 e L c G b 6 w y h A H k b I l D V 6 o v y d S E m o 9 D X 3 b G R I z 1 q v e X P z P 6 y U m u P V S L u P E M E m X i 4 J E Y B P h + e 9 4 y B W j R k w t I V R x e y u m Y 6 I I N T a h g g 3 B X X 1 5 n b S v K m 6 1 c t 2 s l m r 1 L I 4 8 n M E 5 l M G F G 6 j B P T S g B R Q m 8 A y v 8 I Z i 9 I L e 0 c e y N Y e y m V P 4 A / T 5 A / V F j q 0 = < / l a t e x i t > Auth Request (AU T HQ) < l a t e x i t s h a 1 _ b a s e 6 4 = " m J N e L j g P B / h 6 g W E + H I X F S Q 2 1 + T Q = " > A A A B 7 3 i c b V B N T 8 J A E J 3 i F + I X 6 t H L R m K C F 9 I a j B 5 R L x w h o U A C D d k u W 9 i w 3 d b d r Q l p + B N e P G i M V / + O N / + N C / S g 4 E s m e X l v J j P z / J g z p W 3 7 ...
... Luvisotto et al. [6] discuss the salient features of WiFi's physical layer to address the requirements of industrial communication systems, compared to cellular and 802.15 networks. Similarly, Tramarin et al. [7] discussed the suitability of 802.11n in industrial applications. Abedi et al. [3] report the physical layer energy consumption range of WiFi and BLE are 10-100 nJ/bit and 275-300 nJ/bit, respectively; thereby confirming the higher efficiency of WiFi. ...
Enhancing the energy efficiency of WiFi IoT stations introduces unique challenges compared to 802.15.4 and BLE. The four essential operations performed to ensure connectivity between stations and the access point in a WiFi network are association, periodic beacon reception, maintaining association, and station wake up. Understanding and enhancing these operations are essential for building energy-efficient and dependable IoT systems. However, it is unclear how the software and hardware configuration of station and access point, concurrent traffic, power management, and security protocols affect the reliability and energy efficiency of these operations. In this paper, first, we present a thorough analysis of the association cost of WPA2 and WPA3 and mitigate the effect of key computation on association overhead. Second, we prove that increasing listen interval to reduce beacon reception wake-up duration may negatively impact energy efficiency. We identify the primary causes of this problem subject to link quality estimation algorithm and beacon delay. Third, we show that maintaining association by relying on access-point-based polling is not reliable. In particular, we confirm the wake-up delay of low-power stations is highly affected by factors such as channel utilization and beacon listen interval. We also confirm that key renewal aggravates the chance of disassociation.
... Industry 4.0 refers to the next evolutionary step of industrial development that enables interconnection, automatization, and digital management of industrial ecosystems [1]. Industry 4.0 has become the focus of many researchers, manufacturers, and governments as a way to make factories smart by optimizing energy consumption and resource use [1,2]. ...
... Industry 4.0 refers to the next evolutionary step of industrial development that enables interconnection, automatization, and digital management of industrial ecosystems [1]. Industry 4.0 has become the focus of many researchers, manufacturers, and governments as a way to make factories smart by optimizing energy consumption and resource use [1,2]. Industry 4.0 may benefit from wireless networks, which have proliferated in many environments as a low-cost and high-performing "workaround" to physical wired networks in environments where such infrastructure is prohibitively expensive or challenging to install and maintain [1,3]. ...
... Industry 4.0 has become the focus of many researchers, manufacturers, and governments as a way to make factories smart by optimizing energy consumption and resource use [1,2]. Industry 4.0 may benefit from wireless networks, which have proliferated in many environments as a low-cost and high-performing "workaround" to physical wired networks in environments where such infrastructure is prohibitively expensive or challenging to install and maintain [1,3]. Wireless networks offer numerous advantages over wired networks, such as mobility and scalability, low installation costs, and independence from physical damage or deterioration of cables [4]. ...
Wireless networks, including IEEE 802.11-based or Wi-Fi networks, are inexpensive and easy to install and therefore serve as useful connectivity alternatives in areas lacking wired-network infrastructure. However, IEEE 802.11 networks may not always provide the seamless connectivity and minimal throughput required for Industry 4.0 communications because of their susceptibility to interference from other devices operating in the unlicensed “Industrial, Scientific, and Medical” frequency band. Here we analyzed how a wireless audio transmitter operating on this band influences the throughput of an IEEE 802.11 b/g/n network under laboratory conditions. Wireless audio transmission reduced mean throughput by 85%, rendering the IEEE 802.11 b/g/n network nearly unusable. Our analysis suggests that in order for IEEE 802.11 wireless networks to support Industrial 4.0 applications, attention should be paid to the physical layer as well as the data or upper layers, and critical services should not transmit on the 2.4 GHz band. These findings may contribute to understanding and managing IEEE 802.11 wireless networks in various Industry 4.0 contexts.
... This fact is a major drawback for realtime services in networks where a massive number of nodes are potentially operating in a crowded spectrum environment [5]. In addition, the standard lacks efficiency for traffic profiles associated to industrial wireless communications (short packets) [6]. ...
... In 2009, the IEEE standardization committees released the standard version IEEE 802.11n [20], which offers up to five times faster transmission modes in comparison with its predecessor, especially due to the introduction of Multiple-Input Multiple-Output (MIMO) systems [21]. Authors in [6] have tested it on real-time industrial communications and the outcome has been a set of guidelines and recommendations in terms of reliability and latency. However, reliability values are only presented up to PER values of 10 -1 , which is far away from typical industrial performance requirements and it is not realistic to extrapolate those values to very low PER values taking into account the high variance of the industrial wireless propagation channels. ...
... The performance of latest LDPC codes, for instance, is less than half a dB away from the Shannon limit [31]. The second driver for feasibility is the implementation of the signal cancellation structure proposed in [6], which reduces significantly the complexity of the [32]. In [6], a comprehensive comparison of the spectral efficiency of NOMA and traditional TDM/FDM schemes was presented. ...
Industry 4.0 and Industrial Internet refer to the expected revolution in production, utility management and, in general, fully automated, interconnected and digitally managed industrial ecosystems. One of the key enablers for Industry 4.0 lies on reliable and timely exchange of information and large scale deployment of wireless communications in industry facilities. Wireless will bring solutions to overcome the main drawbacks of the current wired systems: lack of mobility, deployment costs, cable damage dependency and scalability. However, the strict requirements in reliability and latency of use cases such as Factory Automation (FA) and Process Automation (PA) are still a major challenge and a barrier for massive deployment of currently available wireless standards. This paper proposes a PHY/MAC wireless communication solution for FA and PA based on Non-Orthogonal Multiple Access (NOMA) in combination with the 802.11n standard. The communication system proposed aims at delivering two different sets of services. The first service class is composed of Critical Services (CS) with strict restrictions in reliability and latency. The same communication system should convey also a second group of services, referred as Best Effort (BE) with more relaxed boundary conditions. The proposal theoretical background, a detailed transmission-reception architecture, the physical layer performance and the MAC level system reliability are presented in this paper. The solution provides significantly better reliability and higher flexibility than TDMA systems, jointly with a predictable control-cycle latency.
... However, these solutions use the 802.11 PHY that is not very efficient for short packets, thus their cycle times and latencies are in the order of milliseconds [16]. ...
... Greater BW can significantly increase the system throughput, as the number of carriers inside each OFDM symbol typically grows proportionally with the BW. However, using a higher BW may not reduce the frame duration of short packets, because the extra OFDM data carriers may remain unused [16]. ...
... There are few wireless systems that are indeed able to fulfill the targeted sub-millisecond cycle time. For instance, 802.11g/n/ac have low efficiency in the transmission of short packets due to its long preamble [16], and then they cannot support low cycle times. 5G-NR minimum achievable cycle time is in the range of 2 ms even with BW > 100 MHz [7], which is above the sub-millisecond cycle time pursued. ...
Real-time industrial applications in the scope of the industry 4.0. present significant challenges from the communication perspective: low latency, ultra-reliability, and determinism. Given that wireless networks provide a significant cost reduction, lower deployment time, and free movement of the wireless nodes, wireless solutions have attracted the industry attention. However, industrial networks are mostly built by wired means because state-of-the-art wireless networks cannot cope with the industrial applications requirements. In this paper, we present the hardware implementation of wireless SHARP (w-SHARP), a promising wireless technology for real-time industrial applications. w-SHARP follows the principles of Time-Sensitive Networking and provides time synchronization, time-aware scheduling with bounded latency, and high reliability. The implementation has been carried out on a Field Programmable Gate Array-based Software Defined Radio platform. We demonstrate, through a hardware testbed, that w-SHARP is able to provide ultra-low control cycles, low latency, and high reliability. This implementation may open new perspectives in the implementation of high-performance industrial wireless networks, as both PHY and MAC layers are now subject to be optimized for specific industrial applications.
... In the Wi-Fi domain, we consider the most common IEEE 802.11n standard [12], typically used in industrial environments [13]. Similarly to NB-IoT, IEEE 802.11n is an OFDMbased standard. ...
... CSI values contain complex-valued average channel gains estimated per each OFDM subcarrier. In IEEE 802.11n standard, each OFDM symbol has N = 64 subcarriers, out of which 52 is reserved for the data [13], while the rest represent the guard band. 1) Data Set Generation: In order to collect data set, we deploy our setup in an indoor environment, placing the IoT devices on 20 predefined grid points, as shown on Fig. 5. The IoT devices and the AP are stationary. ...
Industrial Internet of Things (IoT) systems increasingly rely on wireless communication standards. In a common industrial scenario, indoor wireless IoT devices communicate with access points to deliver data collected from industrial sensors, robots and factory machines. Due to static or quasi-static locations of IoT devices and access points, historical observations of IoT device channel conditions provide a possibility to precisely identify the device without observing its traditional identifiers (e.g., MAC or IP address). Such device identification methods based on wireless fingerprinting gained increased attention lately as an additional cyber-security mechanism for critical IoT infrastructures. In this paper, we perform a systematic study of a large class of machine learning algorithms for device identification using wireless fingerprints for the most popular cellular and Wi-Fi IoT technologies. We design, implement, deploy, collect relevant data sets, train and test a multitude of machine learning algorithms, as a part of the complete end-to-end solution design for device identification via wireless fingerprinting. The proposed solution is currently being deployed in a real-world industrial IoT environment as part of H2020 project COLLABS.
... To this extent, we have reproduced the experimental setup proposed in [13] to obtain measurements of the PER-SNR function. With an approach similar to [14], we then carried out a fine tuning of the main parameters of the OMNet++ Wi-Fi channel model. ...
... As pointed out in [8], it includes the time necessary to execute both the FSoE and the underlying protocol stacks in both master and slave, and the time to transmit the safety frame and the slave's answer message. The latter time, assuming no collision during the transmission [13], may be considered deterministic. Conversely, the former time usually depend to the characteristic of the device where protocols and applications are implemented, such as the computational capabilities, as well as operating system calls, memory management, etc., which may introduce random latencies and jitter. ...
In recent years, Factory Automation is evolving towards the so-called Industry 4.0, and the creation of a smart factory ecosystem comprising of ubiquitously interconnected objects, namely the Industrial Internet of Things (IIoT), is gaining much research interest. This paradigm aims at developing new smart technological equipment and protocols, thus providing interconnection among "factory objects" anywhere and at any time. In this context, people and machines have to safely cooperate and a high level of protection needs to be guaranteed for both operators and the surrounding environment. For this reason, safety systems, aiming at decreasing risks and failure probabilities , are nowadays of uttermost importance. Several Functional Safety communication protocols have been developed during these years pointing to increase data integrity and guarantee protection in a safety system. Popular examples are Fail Safe over EtherCAT (FSoE), ProfiSAFE, and OPC-UA Safety. These protocols, although conceived for wired networks, can be in principle adopted also by wireless communication, as they are developed by using a black channel approach. Nevertheless, the implementation of these protocols over different wireless networks is challenging as they might not ensure the required Safety Integrated Level (SIL). This paper, moving from the aforementioned observations and the need for wireless solutions in the IIoT context, focuses on proposing a possible implementation of FSOE over Wi-Fi, running UDP at the transport layer. In particular, by using suitable experimental outcomes, an OMNeT++ simulator has been calibrated, thus enabling the possibility to analyze the proposed protocol in wide industrial systems.
... Determinism is another mandatory condition that is difficult to achieve with current wireless standards. In recent literature, in order to enable a massive deployment of industrial wireless networks, several technologies and standards have been proposed: IEEE 802.11 [5] [6], Bluetooth [7], 802.15.4 [8], LTE [9], and 5G [10] [11]. However, the latest versions of Wi-Fi and 5G stand out among all of them for a considerable improvement in critical applications. ...
... However, the 802.11ax transceiver presents a much higher complexity than 802.11n and its combination with NOMA may present several challenges. That is why it has been opted to use 802.11n and maintain a tradeoff between complexity and the performance parameters of industrial environments (i.e., reliability and latency) [6]. ...
New use cases and applications in factory automation scenarios impose demanding requirements for traditional industrial communications. In particular, latency and reliability are considered as some of the most representative Key Performance Indicators (KPI) that limit the technological choices addressing wireless communications. Indeed, there is a considerable research effort ongoing in the area of wireless systems, not only from academia, but also from companies, towards novel solutions that fit Industry 4.0 KPIs. A major limitation for traditional wireless architectures is related to the harsh nature of the industrial propagation channel. Accordingly, this paper addresses these challenges by studying the reliability and latency performance of the joint use of different retransmission schemes in combination with Non-Orthogonal Multiple Access (NOMA) techniques. Two general retransmission schemes have been tested: time-based and spatial diversity-based retransmissions. An adaptive injection level NOMA solution has been combined with the retransmission schemes to improve the reliability of critical information. In all cases, a particular set of simulations has been carried out varying the main parameters, such as modulation, code rate and the injection level. Moreover, the impact of the number of transmitters in relation to the communication reliability has been analyzed. Results show that spatial diversity-based retransmissions overcome considerably the reliability obtained with time-domain retransmissions while maintaining assumable latency rates.
... Real-time applications as VoIP enables users to use the Internet as a transmission medium by sending voice data in packets using Internet Protocol (IP) rather than by traditional circuit-switched Public Switched Telephone Network (PSTN).In WLANs where a mix of applications have been deployed, a number of factors that affect the network performance should be addressed and evaluated such as the wireless network architectures (BSS, ESS and IBSS) and IEEE MAClayer technologies [2]. Moreover, as demonstrated in [3] the optimum performance of IEEE technologies deployed in real-time industrial communication systems not always guaranteed to recent technologies (802.11n) over the older one (802.11g), for this exact reason our work provides analyzing study that suggests to the user/client the optimum technology/technologies and network architecture without wasting resources nor getting in the issues of randomly choosing specific technologies then redesigning the whole configuration. ...
... , when 10 ≥ N > 5, if the client is implementing a network using a number of nodes between 5 and 10, then ESS provide optimum performance.IEEE 802.11a technology performs the ideal technology if the network is only configured in circular and uniform distributions. In the case of the IBSS results, the 802.11eproduces the optimum performance if it is only configured in uniform and random distributions as demonstrated inFig.6(b).3. The third category, where 20 ≥ N > 10, if the client is going to build a medium-size network with the number of nodes from 10 to 20, then ESS provide the optimum performance. ...
This paper proposes an algorithm approach to examine the impact of using different application services with various IEEE technologies in order to identify the optimum technology among different network architectures;Basic Service Set (BSS), Extended Service Set (ESS), and the Independent Basic Service Set (IBSS).Specifically, we utilize an algorithmic and mathematical scheme to allow user/client to analyse the optimum WLAN technology and network architecture"s performance to be used for a given mix of internet applications configured across three spatial distributions (circular, uniform, random).Moreover, the proposed algorithm considers multi-criteria access network selection such as spatial distribution and number of nodes, hence to facilitate the provision of the best overall network performance and high-quality services. For further throughput enhancement, we adopt the Quality of Service (QoS) metrics for each application to develop a computational algorithm model to provide precise numerical results used to rank and identify the optimum overall performance"s technologies. Our numerical results corroborate the analytical framework results and demonstrate the strength of the proposed algorithm.
... This schedule withstand in the presence of the packet dropouts of the nodes used for time triggering and the nodes of event triggering. In [108], the reliability and time of service of IEEE 802.11n was analyzed for communication applied in industry. ...
A wireless networked control system (WNCS) consists of a dynamic system to be controlled, sensors, actuators, and a remote controller. A WNCS has two types of wireless transmissions, i.e., the sensor's measurement transmission to the controller and the controller's command transmission to the actuator. In this paper, we are surveying the literature on the communication networks in WNCSs and the challenges related to them, such as the communication standards, delay, Packet dropout, and delay jitter. Then, the control approaches in the design of a WNCS are presented, including the interactive design approaches and the joint design approaches. Also, several applications of WNCSs have been discussed in terms of their structure, functionality, and control design. These applications include Intra-Vehicle Wireless networks, Wireless Avionics Intra-Communication, Building Automation, and Water pumping. After that, security issues in WNCSs from a control engineering point of view are detailed while focusing on the major kinds of cyber attacks affecting WNCSs. Finally, future directions and conclusions are summarized at the end of the paper.
... First, the Automatic Repeat Request techniques introduce some check-bits in the transmitted packet for retransmitting the erroneous messages. However, on the other hand, retransmissions introduce undesirable delay during the packet transmission [12]. The other strategy is the FEC. ...
Industry 4.0 aims to digitize industrial processes entirely, and wireless technologies represent one of the enablers for scalable and flexible communications. However, the current standards and proprietary solutions do not meet the industry's tight requirements in fundamental use cases such as Factory Automation (FA). One of the key research challenges towards replacing wired fieldbuses with wireless links is the design of techniques that enable real-time and deterministic behavior when transmitting short packets. Forward Error Correction (FEC) techniques are critical to this objective, and coding/decoding algorithms must comply with reliability and low latency specifications. This paper surveys existing FEC techniques for short packet transmissions. Compared to other survey papers in the field, we propose several FEC candidate techniques specifically suitable for FA wireless systems. We explore four of these techniques, also examining hardware architecture proposals. The paper proposes a methodology to evaluate their latency and reliability performance. We finally discuss the lessons learned and challenges for future research.
... In recent literature, several wireless technologies have been proposed to enable the deployment of wireless networks in the industry. Some of the most representative alternatives are based on standards IEEE 802.15.4 (e.g., Bluetooth [6]), IEEE 802.11 [7] and 5G [8]. It is worth mentioning the work done by O. Seijo et al. [9], where they developed Wireless-SHARP (W-SHARP), a promising wireless technology for real-time industrial applications. ...
... The residual error rate remains below non-SCL P ue except for very high SNR scenarios (greater than 25 dB), where masquerade errors push residual error rate over P ue . Nevertheless, the typical SNR at the receiver will be below this value in real deployments [23]. In more realistic scenarios, non-CRC countermeasures allow reducing the overall residual system error rate, since not all CRC undetected errors would pose a problem to the safety function. ...
... In 802.11n, the A-MPDU and A-MSDU schemes can aggregate packets towards a single destination and are designed for throughput maximization. However, the A-MPDU and A-MSDU schemes cannot achieve low latency because of the time consumption for generating the aggregated packet [19]. Moreover, the packet aggregation mechanism proposed for WirelessHART focused on the 802.15.4 adhoc mode and cannot be implemented on the considered 802.11 infrastructure mode [20][21][22]. ...
Wireless Time-Sensitive Networking (WTSN) has emerged as a promising technology for Industrial Internet of Things (IIoT) applications. To meet the latency requirements of WTSN, wireless local area network (WLAN) such as IEEE 802.11 protocol with the time division multiple access (TDMA) mechanism is shown to be a practical solution. In this paper, we propose the RT-WiFiQA protocol with two novel schemes to improve the latency and reliability performance: real-time quality of service (RT-QoS) and fine-grained aggregation (FGA) for TDMA-based 802.11 systems. The RT-QoS is designed to guarantee the quality-of-service requirements of different traffic and to support the FGA mechanism. The FGA mechanism aggregates frames for different stations to reduce the physical layer transmission overhead. The trade-off between the reliability and FGA packet size is analyzed with numerical results. Specifically, we derive a critical threshold such that the FGA can achieve higher reliability when the aggregated packet size is smaller than the critical threshold. Otherwise, the non-aggregation scheme outperforms the FGA scheme. Extensive experiments are conducted on the commercial off-the-shelf 802.11 interface. The experiment results show that compared with the existing TDMA-based 802.11 system, the developed RT-WiFiQA protocol can achieve deterministic bounded real-time latency and greatly improves the reliability performance.
... The IEEE 802.11 standard is not adequate for stringent, deterministic industrial applications but sometimes is used. Experimental amendments were proposed in [22,23]. The incipient IEEE 802.11ah standard, defined in 2017, is aimed to support IoT applications [24]. ...
The nature of wireless propagation may reduce the QoS of the applications, such that some packages can be delayed or lost. For this reason, the design of wireless control applications must be faced in a holistic way to avoid degrading the performance of the control algorithms. This paper is aimed at improving the reliability of wireless control applications in the event of communication degradation or temporary loss at the wireless links. Two controller levels are used: sophisticated algorithms providing better performance are executed in a central node, whereas local independent controllers, implemented as back-up controllers, are executed next to the process in case of QoS degradation. This work presents a reliable strategy for switching between central and local controllers avoiding that plants may become uncontrolled. For validation purposes, the presented approach was used to control a planar robot. A Fuzzy Logic control algorithm was implemented as a main controller at a high performance computing platform. A back-up controller was implemented on an edge device. This approach avoids the robot becoming uncontrolled in case of communication failure. Although a planar robot was chosen in this work, the presented approach may be extended to other processes. XBee 900 MHz communication technology was selected for control tasks, leaving the 2.4 GHz band for integration with cloud services. Several experiments are presented to analyze the behavior of the control application under different circumstances. The results proved that our approach allows the use of wireless communications, even in critical control applications.
... Due to the increase in the density of APs in WLAN networks, problems related to their performance have been found, which may be the result of lack of policies for user management, about traffic load in AP, inadequate selection of frequencies between channels, electromagnetic interference, among other aspects; generating that the APs are not able to attend the required volumes of traffic in an adequate way in order to offer adequate levels of QoS (Quality of Service) to the users who need to make use of this service [6]. In this scenario, WLAN networks are unable to harness their full potential. ...
The wireless networks supported in the 802.11 standard play an important role in the field of connectivity, due to the benefits related to mobility, availability, speed and low cost of implementation. This study aims to experimentally find the factors that affect the performance of a WISP (Wireless Internet Service Provider) based on the 802.11 standard. In the proposed scenario, the behavior of the Throughput and delays in the transmission processes were analyzed based on factors such as frequency, distance and the number of stations connected to the Access point under study. In the results obtained, it was possible to demonstrate the levels of influence that the factors mentioned above reflected in relation to the performance of the link and the available bandwidth. The proposed model can be considered as an excellent tool for the analysis of future works related to the design of WISP.
... Sometimes, the IEEE 802.11 standard is used at industrial communications, but in general, it does not ensure the QoS requirements. Some studies propose using WiFi coordinated channels to achieve a real-time deterministic behavior at industrial applications [24]. Other studies propose algorithms specifically aimed at control applications [2]. ...
Wireless technologies are being introduced in industrial applications since they provide certain benefits, such as the flexibility to modify the layout of the nodes, improving connectivity with monitoring and decision nodes, adapting to mobile devices and reducing or eliminating cabling. However, companies are still reluctant to use them in time-critical applications, and consequently, more research is needed in order to be massively deployed in industrial environments. This paper goes in this direction by presenting a novel wireless acquisition system aimed at industrial applications. This system embeds a low-cost technology, such as XBee, not frequently considered for deterministic applications, for deploying industrial applications that must fulfill certain QoS requirements. The use of XBee 900 MHz modules allows for the use of the 2.4 GHz band for other purposes, such as connecting to cloud services, without causing interferences with critical applications. The system implements a time-slotted media access (TDMA) approach with a timely transmission scheduling of the messages on top of the XBee 900 MHz technology. The paper discusses the details of the acquisition system, including the topology, the nodes involved, the so-called coordinator node and smart measuring nodes, and the design of the frames. Smart measuring nodes are implemented by an original PCB which were specifically designed and manufactured. This board eases the connection of the sensors to the acquisition system. Experimental tests were carried out to validate the presented wireless acquisition system. Its applicability is shown in an industrial scenario for monitoring the positioning of an aeronautical reconfigurable tooling prototype. Both wired and wireless technologies were used to compare the variables monitored. The results proved that the followed approach may be an alternative for monitoring big machinery in indoor industrial environments, becoming especially suitable for acquiring values from sensors located in mobile parts or difficult-to-reach places.
... Furthermore, the availability of IBSS, BSS, and ESS have increased the difficulty of deciding which network architecture is best to use, regarding the assigned wireless network resources, to provide optimum network quality. Moreover, as demonstrated in A. Mohd Ali et al. [21] the optimum performance of IEEE technologies deployed in real-time industrial communication systems not always guaranteed to recent technologies (802.11n) over the older one (802.11g), for this exact reason our work provides an analysing study that suggests to the user the optimum technology/technologies and network architecture without wasting resources nor getting in the issues of randomly choosing specific technologies then redesigning the whole configuration. ...
This research developed a novel algorithm to evaluate Voice over Internet Protocol (VoIP) metrics of different IEEE 802.11 technologies in order to identify the optimum network architecture among Basic Service Set (BSS), Extended Service Set (ESS), and the Independent Basic Service Set (IBSS). The proposed algorithm will yield the rank order of different IEEE 802.11 technologies. By selecting the optimum network architecture and technology, the best overall network performance that provides a good voice quality is guaranteed. Furthermore, it meets the acceptance threshold values for the VoIP quality metrics. This algorithm was applied to various room sizes ranging from 2x3m to 10x14m and the number of nodes ranged from one to forty. The spatial distributions considered were circular, uniform, and random. The Quality of Service (QoS) metrics used were delay, jitter, throughput and packet loss.
... For the latter crucial calibration phase, we focused on the relationship between packet error rate (PER) perceived at the Data-Link Layer, that hence depends on the outcomes of the NIST error model, with respect to the SNR at the receiver. To this aim, we referred to the experimental setup proposed in [16], where this PER-SNR relationship has been determined experimentally. Reproducing these measurements data as a reference, we hence fine tuned the main parameters of the OMNet++ NIST error model, in a typical calibration procedure. ...
... Recently there has been a growing trend to employ wireless technology in factory systems [1] thanks to the continual improvement in data-rate, multi-user support and robustness. These systems include IEEE 802.11 wireless local area network (WLAN) [2] and wireless personal area networks such as IEEE 802.15.1 or IEEE 802.15.4 [3]. Factory communication infrastructure needs to support transmission of time critical data at sufficient rate to avoid control instability and ultimately failure. ...
Factory communication systems require highly reliable links with predictable performance and quality of service in order to avoid outages that can damage the production-line process. Communication anomalies can be caused by narrowband interference which is difficult to identify and track from the time-domain information only. This paper describes a methodology for classifying increasing severity and types of interference in order to improve throughput prediction. Received signal strength (RSS) data is collected from both a ray-tracing simulation and a Wireless Local Area Network (WLAN) measurement campaign with a transmitter mounted on an actual automated guided vehicle (AGV). Scalogram time-frequency images are computed from the RSS signal and a convolutional neural network (CNN) is then trained to recognize the spectral features and enable the interference classification. The block random interference could be correctly classified on over 65% of the occasions in the ray-traced channel at 30 dB SNR.
... The benefits of using 802.11 for building high-rate, energy-efficient WSNs have been studied recently. Tramarin et al. [65] evaluated the suitability of 802.11n in industrial applications from its physical layer point of view. Luvisotto et al. [10] provided an overview of the requirements of industrial wireless networks and studied the suitability of 802.11 to address these requirements, compared to cellular and 802.15 networks. ...
Wireless Sensor Networks (WSNs) are being used in various applications such as structural health monitoring and industrial control. Since energy efficiency is one of the major design factors, the existing WSNs primarily rely on low-power, low-rate wireless technologies such as 802.15.4 and Bluetooth. In this paper, by proposing , we strive to tackle the challenges of developing ultra-high-rate WSNs based on the 802.11 (WiFi) standard. As an illustrative structural health monitoring application, we consider spacecraft vibration test and identify system design requirements and challenges. Our main contributions are as follows. First, we propose packet encoding methods to reduce the overhead of assigning accurate timestamps to samples. Second, we propose energy efficiency methods to enhance the system’s lifetime. Third, to enhance sampling rate and mitigate sampling rate instability, we reduce the overhead of processing outgoing packets through the network stack. Fourth, we study and reduce the delay of processing time synchronization packets through the network stack. Fifth, we propose a low-power node design particularly targeting vibration monitoring. Sixth, we use our node design to empirically evaluate energy efficiency, sampling rate, and data rate. We leave large-scale evaluations as future work.
... Although wired connections are still commonly used in the industry due to their high reliability, wireless systems offer an interesting improvement in scalability, cost reduction, and mobility that make them an ideal candidate for future industrial communication systems [44]. Several technologies and standards have been proposed towards a massive deployment of industrial wireless networks, such as IEEE 802.11 [42,43], Bluetooth [39], 802.15.4 [6], LTE [4], or WirelessHart [19]. However, none of those technologies can be considered the optimum solution for implementation in the industrial environment due to the strict characteristics and requirements involved. ...
5G is expected to cover a wide range of potential use cases due to its flexible and configurable physical layer waveform. One of the use cases proposed is the application of 5G on Ultra-Reliable Low Latency Communication (URLLC), which are characterized by very challenging reliability/availability and latency requirements. In addition, multimedia applications are being consolidated as a relevant aspect of current industrial environments. In order to meet those strict requirements, Radio Resource Management (RRM) becomes a critical phase of any wireless communication system. This work proposes the use of power domain Non-Orthogonal Multiple Access (P-NOMA) techniques in 5G RRM for factory automation environments. The research presented in this paper includes the design and evaluation of different RRM algorithms based on P-NOMA and on traditional Orthogonal Multiple Access (OMA) techniques, such as Time/Frequency Division Multiplexing Access (T/FDMA). Those algorithms are comprehensively explained and oriented to optimize the resource allocation based on different metrics (i.e., capacity, number of users, or cycle time). Moreover, extensive results are presented, where the performance of NOMA and OMA techniques is compared in terms of different metrics under the influence of several parameters, such as payload, bandwidth, or the number of users. Results indicate that although both NOMA and OMA provide positive aspects, eventually NOMA-based RRM algorithms are the solutions that enhance considerably the spectral efficiency.
... For sending and receiving data, there are three mainstream industrial transport-oriented communication channels: dedicated Fieldbus networks [71], Ethernet-based networks [72], and Wireless Sensor Networks (WSNs) [73]. Among them, WSN offers more flexible installation options. ...
Mass personalization is becoming a reality. It requires responsive and flexible manufacturing operations for producing individualized products in dynamic batch sizes at scale in a cost-effective way. Therefore, manufacturing systems should timely respond to meet changing demands and conditions in the factory, in the supply network, and in customer needs. However, current manufacturing systems fail to adapt to dynamic production environments via changing system configurations and production plans while maintaining stable production performance. Therefore, a manufacturing system is required to be capable of self-optimizing manufacturing operations to achieve flexible, autonomous, and error-tolerant production in the mass person-alization context. In this article, we systematically reviewed the literature on Self-Organizing Manufacturing Systems (SOMS) and proposed a complete concept of Self-Organizing Manufacturing Network (SOMN) as the next-generation manufacturing automation technologies for achieving mass personalization. Our review started by tracing the roots, origin, and state-of-the-art research of SOMS and concluded that the existing SOMS work could not achieve the mass personalization goal. As a focus of this review paper, we systematically discussed self-organizing manufacturing's functional requirements to achieve mass personalization and proposed Self-Organizing Manufacturing Network. The concept, functions and essential technological system components (i. e., system modeling and control architecture, peer communications, and adaptive manufacturing control) are discussed by reviewing existing work and highlighting transferrable knowledge from other disciplines. Future research challenges are also discussed.
... From the 1990s, the wireless networks became increasingly popular in the industry due to cables do not restrict it. These wireless networks were mainly adopted by the IEEE 802 protocol group (Tramarin et al. 2015). However, the main challenge of wireless networks was to ensure real-time and reliability capabilities, especially in the manufacturing environment (Vitturi et al. 2013). ...
Industrial Internet of Things (IIoT) is performed based on the multiple sourced data collection, communication, management and analysis from the industrial environment. The data can be generated at every point in the manufacturing production process by real-time monitoring, connection and interaction in the industrial field through various data sensing devices, which creates a big data environment for the industry. To collect, transfer, store and analyse such a big data efficiently and economically, several challenges have imposed to the conventional big data solution, such as high unreliable latency, massive energy consumption, and inadequate security. In order to address these issues, edge computing, as an emerging technique, has been researched and developed in different industries. This paper aims to propose a novel framework for the intelligent IIoT, named Industrial Internet of Learning (IIoL). It is built using an industrial wireless communication network called Low-power wide-area network (LPWAN). By applying edge computing technologies in the LPWAN, the high-intensity computing load is distributed to edge sides, which integrates the computing resource of edge devices to lighten the computational complexity in the central. It cannot only reduce the energy consumption of processing and storing big data but also low the risk of cyber-attacks. Additionally, in the proposed framework, the information and knowledge are discovered and generated from different parts of the system, including smart sensors, smart gateways and cloud. Under this framework, a pervasive knowledge network can be established to improve all the devices in the system. Finally, the proposed concept and framework were validated by two real industrial cases, which were the health prognosis and management of a water plant and asset monitoring and management of an automobile factory.
... They also argued that the overall energy consumption of 802.11 is higher than BLE due to connection establishment and maintaining connection. Tamarin et al. [82] evaluated the suitability of 802.11n in industrial applications from its physical layer point of view. Considering the higher header overhead of 802.11n compared to 802.11g, the former standard has a shorter transmission duration for packets longer than 224 bytes. ...
Wireless Sensor Networks (WSNs) are being used in various applications such as structural health monitoring and industrial control. Since energy efficiency is one of the major design factors, the existing WSNs primarily rely on low-power, low-rate wireless technologies such as 802.15.4 and Bluetooth. In this paper, we strive to tackle the challenges of developing ultra-high-rate WSNs based on 802.11 (WiFi) standard by proposing Sensifi. As an illustrative application of this system, we consider vibration test monitoring of spacecraft and identify system design requirements and challenges. Our main contributions are as follows. First, we propose packet encoding methods to reduce the overhead of assigning accurate timestamps to samples. Second, we propose energy efficiency methods to enhance the system's lifetime. Third, we reduce the overhead of processing outgoing packets through network stack to enhance sampling rate and mitigate sampling rate instability. Fourth, we study and reduce the delay of processing incoming packets through network stack to enhance the accuracy of time synchronization among nodes. Fifth, we propose a low-power node design for ultra-high-rate applications. Sixth, we use our node design to empirically evaluate the system.
... The capability of transmissions for this standard is up to 54 Mbps and operates at 5 GHz band [26]. IEEE 802.11n standard improves the performance of WLANs standard development [27]. In order to provide better performance, there are new features that have been incorporated into this standard which are; implementation of OFDM, introduction of MIMO, MIMO power saving, wider channel bandwidth, antenna technology and improve the data throughput by reducing the support for backward compatibility. ...
... Furthermore, the availability of IBSS, BSS and ESS have increased the difficulty of deciding which network architecture is best to use, regarding the assigned wireless network resources, to provide optimum network quality. Moreover, as demonstrated in [15] the optimum performance of IEEE technologies deployed in real-time industrial communication systems not always guaranteed to recent technologies (802.11n) over the older one (802.11g), for this exact reason our work provides an analysing study that suggests to the user the optimum technology/technologies and network architecture without wasting resources nor getting in the issues of randomly choosing specific technologies then redesigning the whole configuration. ...
This paper evaluates the performance of the HTTP Protocol and the FTP Protocol using OPNET simulation (Riverbed Modeler 17.5). In this paper, an algorithm scheme is intended to examine HTTP and FTP services of different IEEE 802.11 technologies in order to define the optimal network architecture between the Basic Service Set (BSS), the Extended Service Set (ESS) and the Independent Basic Service Set (IBSS). In addition, the proposed algorithm considers multi-criteria network access selection, such as spatial distribution and number of nodes, to enable the provision of the best overall network output and high-quality services. The Quality of Service (QoS) metrics used were delay, throughput and loss of packets. This also meets the approval threshold values for HTTP and FTP quality metrics. This algorithm was applied to various room sizes ranging from 2x3 m to 10x14 m and the number of nodes ranged from one to forty.
... Modern wireless communication systems often use MIMO to improve the communication performance by exploiting multiple antennas. MIMO offers different spatial streams that can be either used to increase the throughput or to improve the communication reliability thanks to spatial diversity [24]. ...
... The complete list of the settings used for the experiments is summarized in Table 1. They have been selected to comply with the most common features/requirements of Wi-Fi based real-time industrial networks and their relevant rate adaptation algorithms, as described in [25,[36][37][38]. ...
Factory automation systems based on the IEEE 802.11 Wi-Fi standard may benefit from its Multi-Rate Support (MRS) feature, which allows for dynamically selecting the most suitable transmission rate for the targeted application context. The MRS is implemented by means of rate adaptation algorithms (RAAs), which has already demonstrated to be effective to improve both timeliness and reliability, which are typically strict requirements of industrial real-time communication systems. Indeed, some of such algorithms have been specifically conceived for reliable real-time communications. However, the computational complexity of such algorithms has not been effectively investigated yet. In this paper, we address such an issue, particularly focusing on the execution times of some specific rate adaptation algorithms, as well as on their impact on the automation tasks. In this respect, after a formal description of the algorithms, we present the outcomes of an extensive experimental session, which includes practical measurements and realistic simulations. The obtained results are encouraging, since the measured execution times indicate that rate adaptation algorithms can be profitably adopted by industrial automation systems, allowing for improving their reliability and timeliness without impacting on the overall performance.
... Besides cellular IoT standards, there exist a series of shortrange communication standards, such as wireless local area networks (WLANs), for instance, IEEE 802.11 [12], and wireless personal area networks (WPANs), e.g., IEEE 802.15.1 or IEEE 802.15.4, enabled by bluetooth, Zigbee, etc [13]. ...
... Multiple dense small cells, centrally managed by a cloud radio access network (C-RAN) [37], can be utilized to handle the high data rate and reliability requirements. For factory automation, IEEE 802.15.3 (high-rate WPANs) and 802.15.4 (low rate WPANs), e.g., industrial wireless sensor networks (IWSNs) based on WirelessHART [38], WIA-PA, or WISA, and modified versions of the IEEE 802.11 standard [39] for wireless local area networks (WLANs) can be used depending on different application requirements. IEEE 802.11 ...
... At the same time, the existence of different IEEE 802.11 technologies requires a logical analysis to decide which technology should be used and put into practice. Moreover, as demonstrated in (Tramarin et al. 2015), the optimum performance of IEEE technologies deployed in real-time industrial communication systems is not always guaranteed for recent technologies (802.11n) rather than older ones (802.11g); for this exact reason our work provides an analysing study that suggests to the user the optimum technology/technologies and network architecture without wasting resources nor getting into issues of randomly choosing specific technologies then redesigning the whole configuration. ...
This research developed a novel algorithm to evaluate internet-based services such as VoIP, Video Conferencing, HTTP and FTP, of different IEEE 802.11 technologies in order to identify the optimum network architecture among Basic Service Set (BSS), Extended Service Set (ESS) and the Independent Basic Service Set (IBSS). The proposed algorithm will yield the rank order of different IEEE 802.11 technologies. By selecting the optimum network architecture and technology, the best overall network performance that provides good voice, video and data quality is guaranteed. Furthermore, it meets the acceptance threshold values for the VoIP, Video Conferencing, HTTP and FTP quality metrics. This algorithm was applied to various room sizes ranging from [Formula: see text][Formula: see text]m to [Formula: see text][Formula: see text]m and the number of nodes ranged from 1 to 65. The spatial distributions considered were circular, uniform and random. The Quality of Service (QoS) metrics used were delay, jitter, throughput and packet loss.
... Besides cellular IoT standards, there exist a series of shortrange communication standards, such as wireless local area networks (WLANs), for instance, IEEE 802.11 [12], and wireless personal area networks (WPANs), e.g., IEEE 802.15.1 or IEEE 802.15.4, enabled by bluetooth, Zigbee, etc [13]. ...
We propose a decision triggered data transmission and collection (DTDTC) protocol for condition monitoring and anomaly detection in the industrial Internet of things (IIoT). In the IIoT, the collection, processing, encoding, and transmission of the sensor readings are usually not for the reconstruction of the original data but for decision making at the fusion center. By moving the decision making process to the local end devices, the amount of data transmission can be significantly reduced, especially when normal signals with positive decisions dominate in the whole life cycle and the fusion center is only interested in collecting the abnormal data. The proposed concept combines compressive sensing, machine learning, data transmission, and joint decision making. The sensor readings are encoded and transmitted to the fusion center only when abnormal signals with negative decisions are detected. All the abnormal signals from the end devices are gathered at the fusion center for a joint decision with feedback messages forwarded to the local actuators. The advantage of such an approach lies in that it can significantly reduce the volume of data to be transmitted through wireless links. Moreover, the introduction of compressive sensing can further reduce the dimension of data tremendously. An exemplary case, i.e., diesel engine condition monitoring, is provided to validate the effectiveness and efficiency of the proposed scheme compared to the conventional ones.
The Internet of Things (IoT) empowers the development of heterogeneous systems for
various application domains using embedded devices and diverse data transmission protocols. Collaborative integration of these systems in the industrial domain leads to incompatibility and interoperability at different automation levels, requiring unified coordination to exchange information efficiently. The hardware specifications of these devices are resource-constrained, limiting their performance in resource allocation, data management, and remote process supervision. Hence, unlocking network capabilities with other domains such as cloud and web services is required. This study proposed a platform-independent middleware module incorporating the Open Platform Communication. Unified Architecture (OPC UA) and Representational State Transfer (REST) paradigms. The object-oriented structure of this middleware allows information contextualization to address interoperability issues and offers aggregated data integration with other domains. RESTful web and cloud platforms were implemented to collect this middleware data, provide remote application support, and enable aggregated resource allocation in a database server. Several performance assessments were conducted on the developed system deployed in Raspberry Pi and Intel NUC
PC, which showed acceptable platform resource utilization regarding CPU, bandwidth, and power consumption, with low service, update, and response time requirements. This integrated approach demonstrates an excellent cost-effective prospect for interoperable Machine-to-Machine (M2M) communication, enables remote process supervision, and offers aggregated bulk data management with wider domains.
The industrial environment poses strict requirements to the infrastructure of good and service production and delivery. Communications are not an exception. Wired systems currently dominate in factory premises for their robustness in complex and noisy propagation conditions. They also present ruggedness in front of malicious attackers aiming to bring the communication system down or take over the system under control. Unfortunately, wired systems have severe maintenance, scalability, and operational flexibility limitations. Wireless systems constitute a solution, but they show performance weaknesses in reliability and security. This paper analyzes the security challenges of radio-frequency wireless systems in industrial use cases and aligns different categorization efforts from various sources, focusing on the lower layers of the OSI model (PHY/MAC). The analysis includes a detailed taxonomy of attacks and PHY/MAC countermeasure techniques required to make security compatible with the system requirements of industrial applications. Among the different industrial applications, the focus of this work is directed towards Factory Automation. Finally, based on the wide range of existing attacks and techniques, we propose a methodology for dissecting attack scenarios and designing tailored protection techniques and architectures. A wide diversity of attack situations are described, and the corresponding countermeasures are discussed. Finally, we propose a methodology for dissecting attack scenarios and designing tailored protection techniques and architectures.
Objetivo: Proponer un modelo de optimización para la ubicación de AP en redes WLAN en ambientes Indoor. Metodología: Para su desarrollo se plantearon algoritmos que permiten estimar la probabilidad de corte, el área de cobertura y las coordenadas de ubicación de los AP en función de las dimensiones del escenario, la frecuencia y las condiciones del entorno, soportadas en el modelo de propagación Log-Normal Shadowing Path Loss. Resultados y Conclusiones: Con base en los resultados obtenidos se pudo evidenciar que el modelo propuesto arrojó excelentes resultados al determinar el área de cobertura, la probabilidad de corte para un 80%, la ubicación geográfica de los AP acorde con los parámetros establecidos en cada uno de los escenarios, motivo por el cual se recomendaría el uso del modelo en futuros trabajos de investigación relacionados con la temática objeto de estudio.
Industry 5.0 follows the steps of the Industry 4.0 paradigm and seeks for revolutionizing the way industries operate. In fact, Industry 5.0 focuses on research and innovation to support industrial production sustainability and place the well-being of industrial workers at the center of the production process. Thus, Industry 5.0 relies on three pillars: it is human-centric, it encourages sustainability and it is aimed at developing resilience against disruptions. Such core aspects cannot be fully achieved without a transparent end-to-end human-centered traceability throughout the value chain. As a consequence, Auto-Identification (Auto-ID) technologies play a key role, since they are able to provide automated item recognition, positioning and tracking without human intervention or in cooperation with industrial operators. Although the most popular Auto-ID technologies provide a certain degree of security and productivity, there are still open challenges for future Industry 5.0 factories. This article analyzes and evaluates the Auto-ID landscape and delivers a holistic perspective and understanding of the most popular and the latest technologies, looking for solutions that cope with harsh, diverse and complex industrial scenarios. In addition, it describes a methodology for selecting Auto-ID technologies for Industry 5.0 factories. Such a methodology is applied to a specific use case of the shipbuilding industry that requires identifying the main components of a ship during its construction and repair. To validate the outcomes of the methodology, a practical evaluation of passive and active UHF RFID tags was performed in an Offshore Patrol Vessel (OPV) under construction, showing that a careful selection and evaluation of the tags enables product identification and tracking even in areas with a very high density of metallic objects. As a result, this article serves as a useful guide for industrial stakeholders, including future developers and managers that seek for deploying identification and traceability technologies in Industry 5.0 scenarios.
In this work, we address the problem of remotely controlling possibly unstable systems using wireless channels with communication and control rates on the order of 1 kHz. While remote control over wireless has been used for applications in the kHz control rate range via low-bitrate communication protocols such as IEEE 802.15.4 (Zigbee) and IEEE 802.15.1 (Bluetooth), this represents the first successful demonstration of remotely controlling an unstable system, namely a balancing robot, using the high-bitrate IEEE 802.11 standard (Wi-Fi) with a control/communication rate in the kHz range, thus being suitable for time-critical industrial applications. This is achieved through a suitable design of both the communication and the control layer; the Wi-Fi protocol parameters are modified to reduce communication latency while still abiding to the standard and a model-based controller is implemented using a time-varying buffered Kalman filter to compensate for the sensor-to-controller lossy communication and using a packetized predictive controller to compensate for the controller-to-actuator lossy communication. The validity of this architecture is experimentally tested on a balancing robot, which adopts off-the-shelf embedded hardware (Rasperry Pi) and software (Arduino) within an industrial-like environment where substantial channel interference is present due to coexisting Wi-Fi networks, showing major improvements compared to more traditional emulation-based architectures.
Countless industrial applications can potentially benefit from the implementation of wireless control systems, leading to a widespread research effort to investigate new solutions in the field. Nevertheless, currently available wireless communication standards for industrial automation are not able to achieve high control frequencies. In particular, time–critical applications (e.g. industrial robotics and manipulation) require high sampling frequencies to be properly implemented. The higher throughput provided by IEEE 802.11 (Wi-Fi) can theoretically tame critical applications, although reliability is a key issue. In this work Wi-Fi is adopted to increase the achievable control rates up to 1 kHz, while reliability is guaranteed by mitigating communication flaws through model–based estimation techniques. The core of the proposed approach relies on a modified Kalman filter that exploits a buffer of incoming measures to account for delayed data packets. The proposed solution is validated through a hardware– in–the–loop experiment that features actual Wi-Fi hardware and a commercial embedded PC board. The obtained results give a preliminary, yet valuable, validation of the proposed approach testing the solution on relevant hardware.
WIA-FA and IEEE 802.11 are two most widely adopted industrial wireless standards in discrete manufacturing. However, comprehensive performance comparisons between WIA-FA and IEEE 802.11 are still missing and industrial applications urgently need experimental methods to guide the selection of appropriate wireless technologies. To this end, this paper performs extensive experiments between WIA-FA and IEEE 802.11 in two practical industrial scenarios, with one ordered scenario defining the transmission order of devices and the other order-free scenario imposing no order constraints to the transmission order of devices. Network performance indices of the WIA-FA and IEEE 802.11 networks, including reliability, delay, delay jitter, and disorder rate are compared for different network sizes and data generation periods. Experimental results show that the WIA-FA protocol provides stable network performance, while the network performance of the IEEE 802.11 protocol is random. Additionally, we perform preliminary comparisons of WIA-FA with IEEE 802.11ax and 5G New Radio.
Embedded systems are common in the Internet of Things domain: their integration in vehicles and mobile devices is being fostered in the Internet of vehicles (IoV). IoV has direct applications on intelligent transportation systems and smart cities. Besides basic requirements, such as ease of installation, cost‐effectiveness, scalability, and flexibility, IOV applications need to guarantee energy‐efficient and good‐quality communication. In fact, IoV implementations are commonly based on wireless nodes, which rely on a limited energy source; therefore, an efficient communication among the nodes is desirable to prolong the lifetime of the devices. In particular, the alternation of active and sleep states and the regulation of the transmission power represent two common approaches to save energy. Based on this strategy, an effective fuzzy control system is presented in the paper to manage power consumption and quality of services of IoV applications. Two fuzzy controllers increase the battery life while keeping a good throughput to workload ratio. This technique has been simulated with two leading technologies in IoV: IEEE 802.11b/g/n and IEEE 802.11p. Experimental results show a network lifetime improvement ranging from 30% to 40%, according to the adopted medium access control protocol.
Printed antennas have become an integral part of next-generation wireless communications and have been found to be commonly used to improve system capacity, data rate, reliability, etc. This book covers theory, design techniques, and the chronological regression of the printed antennas for various applications. This book will provide readers with the basic conceptual knowledge about antennas along with advanced techniques for antenna design. It covers a variety of analytical techniques and their CAD applications and discusses new applications of printed antenna technology such as sensing. The authors also present special reconfigurable antennas such as ME dipole, polarization, feeding, and DGS. The book will be useful to students as an introduction to design and applications of antennas. Additionally, experienced researchers in this field will find this book a ready reference and benefit from the techniques of research in printed antennas included in this book. Following are some of the salient features of this book:
Covers a variety of analytical techniques and their CAD applications
Discusses new applications of printed antenna technology such as sensing
Examines the state of design techniques of printed antenna
Presents special reconfigurable antennas such as ME dipole, polarization, feeding, and DGS
The scheduling and control of a class of wireless networked control system is investigated, whose control loop is closed via a shared IEEE 802.15.4 wireless network. By using a gain scheduler within the packet-based control framework and fitting the delay-dependent gains into a time-delay system model, a less conservative self-triggered approach is proposed to determine the sampling update, which consequently enables the design of two network scheduling algorithms to reduce the communication usage. Numerical and TrueTime based examples illustrate the effectiveness of the proposed approach in the sense that it reduces greatly the communication usage while maintaining satisfactory control performance.
This work studies the problem of LQG control when the link between the sensor and the controller relies on a Wi-Fi network. Unfortunately, the communication on a wireless medium is sensitive to noise in the transmission band, which is characterized by the Signal-to-Noise Ratio (SNR). Wi-Fi allows to switch among different bit-rates in real-time thus permitting to trade-off lower loss probabilities for larger latency or vice-versa to achieve better closed-loop performance. To exploit this feature, under a constant SNR scenario, we propose a cross-layer approach where the bit-rate is optimally selected based on a control performance metric (i.e. minimum LQG cost) and a model-based controller is used to compensate for the packet losses. Under time-varying SNR, we additionally propose a (sub-optimal) on-line rate adaptation strategy and we guarantee the closed-loop stability under some mild conditions. Numerical comparisons with emulation-based approaches using TrueTime, a realistic Matlab-based Wi-Fi simulator, are included to show the benefits of the adaptive approach under time-varying SNR scenarios.
In this paper we investigate an innovative solution, to implement high sampling frequency industrial control by means of networked embedded systems connected via WiFi. The basic idea relies on a co-design approach for the control application, which is then able to adapt its sampling period, as well as to tune the Wi-Fi parameters, according to the feedback coming from the network. To this end, we implemented a cross-layer architecture acting at both application and data-link layers, that features a robust frame--delay state estimator, a time-efficient communication policy, and a specific tuning of the critical protocol parameters. Suitable hardware-in--the--loop experiments have been carried out exploiting two different embedded systems available off--the--shelf. The preliminary results, obtained from an extensive experimental campaign, are encouraging since they show that the proposed architecture enables industrial control applications requiring a sampling rate up to 1000~Hz, even in presence of communication impairments.
Industry 4.0 has recently opened a number of new research questions relating to the production scheduling of flexible production systems. The high complexity of flexible production systems` scheduling is reflected in the multi-objective nature of optimisation problems, which cannot be solved satisfactorily with conventional techniques. Researchers are developing various optimisation techniques based on the use of advanced Evolutionary Computation methods and Simulation Modelling, but it is difficult to transmit the proposed solutions to the real world of Industry 4.0. Chapter present new method of Evolutionary Computation and Simulation Modelling for the purpose of comprehensive multi-objective optimisation of flexible production systems. In the research part, chapter present an applied example of the advanced optimisation methods used in order to provide timely and economically sustainable production systems in Industry 4.0. The research results prove the importance and justification of using the proposed CPS architecture ensuring economic and time optimised production systems.
The fourth industrial revolution (Industry 4.0) and its requirements impose radical changes to the underlying networking technologies that will be adopted in future factories. Most popular solutions in use today, in fact, are suitable for Industry 4.0 only in part, and new techniques and devices have to be developed to cope with demanding needs in terms of flexibility, communication bandwidth, real-time behavior, mobility, scalability, energy efficiency, reliability, availability and security. The goal of this paper is assessing the current situation of factory communication systems in the light of their evolution to support Industry 4.0 applications. The paper provides an overview of fundamental concepts in factory communication systems focusing, in particular, on prevalent wireless and wirebound communication protocols and standards. Research challenges in next generation industrial networks are also taken into account.
IEEE 802.11n WLAN was mainly developed to support a high data transmission rate toward 600Mbps based on the aggregation scheme that accumulates several sub-frames to transmit them into a larger frame. This concept reduces overheads and increases efficiency and throughput. Nevertheless, it cannot provide QoS satisfaction for delay sensitive application since it badly affects the delay. To outperform this inefficiency, we have proposed an admission control mechanism named Adaptation of Frame Aggregation AFA-CAC. In this paper, we further investigate the performance of our proposed QoS mechanism on supporting real time applications particularly on audio and video services.
Applying wireless technologies in control systems can significantly enhance the system mobility and reduce the deployment and maintenance cost. Existing wireless technology standards, however either cannot provide real-time guarantee on packet delivery or are not fast enough to support high-speed control systems which typically require 1kHz or higher sampling rate. Nondeterministic packet transmission and insufficiently high sampling rate will severely hurt the control performance. To address this problem, in this paper, we present our design and implementation of a real-time high-speed wireless communication protocol called RT-WiFi. RT-WiFi is a TDMA data link layer protocol based on IEEE 802.11 physical layer to provide deterministic timing guarantee on packet delivery and high sampling rate up to 6kHz. It incorporates configurable components for adjusting design trade-offs including sampling rate, latency variance, reliability, and compatibility to existing Wi-Fi networks, thus can serve as an ideal communication platform for supporting a wide range of high-speed wireless control systems. We implemented RT-WiFi on commercial off-the-shelf hardware and integrated it into a mobile gait rehabilitation system. Our extensive experiments demonstrate the effectiveness of RT-WiFi in providing deterministic packet delivery in both data link layer and application layer, which further eases the controller design and significantly improve the control performance.
Due to their enhanced mobility and reduced configuration and maintenance cost, wireless control systems (WCSs) are widely used in process and vibration control systems, on medical devices, unmanned vehicles and robotics. However, most literatures in WCSs focus on monitoring and low speed control, and less effort has been made on high speed WCSs. It is because most existing wireless communication protocols cannot provide real-time and reliable communication links with preferable high speed by taking energy saving into consideration.
The application of the "Parallel Redundancy Protocol" (PRP) according to IEC 62439-3 with two diverse redundant wireless channels achieves an improved overall wireless communication channel. Performance parameter like jitter and reliability increase significantly compared to the single wireless channels. In this work, a series of measurements on a redundant setup with two parallel WLANs according to IEEE 802.11n in diverse configuration settings is conducted and the results presented. A Markov model for the parallel redundant system is developed and the analytical results compared against the measurements.
The performance of the IEEE 802.11 WLAN are influenced by the wireless channel characteristics that reflect on the signal-to-noise ratio (SNR), particularly in industrial communication systems, that often operate in harsh environments. In order to cope with SNR reductions, the IEEE 802.11 WLAN specification suggests to adapt (reduce) the transmission rate, since the modulation techniques employed at the lower rates are more robust. However, the standard does not define any rate adaptation (RA) technique, leaving the actual implementation to the device manufacturers choice. In this paper we focus on RA techniques for industrial communication systems that are typically subjected to tight reliability and timing requirements. In detail, we compare the performance figures of a general purpose widespread technique, namely the automatic rate fallback (ARF), with those of the RA techniques actually implemented on two commercially available IEEE 802.11 devices via a set of practical experiments. The obtained results show that these techniques are characterized by a relevant number of packet retransmissions that may introduce a considerable randomness on the service time, possibly leading to performance degradation. Consequently, we propose two new techniques and evaluate their behavior by means of numerical simulations carried out for typical industrial traffic profiles. The outcomes are encouraging since the proposed RA techniques show in most cases better performance than ARF.
In this paper, we consider retransmission strategies for centralized cyclic polling-based systems over wireless channels subject to external interference. The considered strategies differ in the time when retransmissions for one particular node are carried out, and in the number of retransmissions that can be carried out for one node. We show experimentally and by simulation that two related strategies introduced in this paper, called the queueing-based strategies, significantly outperform the traditional strategy (in which all admissible trials towards one node are carried out subsequently) in terms of the average number of nodes that cannot be successfully served in a cycle. These performance gains are achieved without increasing the average total transmission effort.
A growing number of industrial applications incorporate multimedia information processing. These multimedia applications are commonly distributed and subject to time constraints that must be met across networks without creating intolerable interference over typical control flows. However, multimedia traffic, in general, and video streaming, in particular, have specific characteristics that conflict with the operational framework of conventional real-time protocols. In particular, video compressors generate highly variable bit-rate streams that mismatch the constant-bit-rate channels typically provided by real-time protocols, severely reducing the efficiency of network utilization. This paper focuses on low-latency multimedia transmission over Ethernet with dynamic quality-of-service (QoS) management. We propose a multidimensional mechanism that controls, in an integrated way, both the compression parameters and the network bandwidth allocated to each stream. The goal is to provide the best possible QoS to each stream, recomputing the compression levels and network bandwidth whenever significant events, such as channel setup/teardown, or structural changes happen. This paper also presents novel QoS metrics based both on the image quality and network parameters. Several experiments with prerecorded video streams illustrate the advantages of the proposed approach and the convenience of the metrics.
Urban facility interconnection networks require a robustness and reliability usually found in public networks or private cable and radio networks in licensed bands. Both factors mean an increase in costs, which also increase as the size of the network increases. The recent rise in use of wireless technologies in open wavebands has attracted the interest of the industry in the spread of these types of links, even though they have a lower level of robustness and reliability, which must be improved using communication mechanisms and protocols. This aspect directly affects real time applications, such as VoIP and video-streaming, and determines the viability of these systems in real installations. This paper evaluates the performance of control and real time multimedia traffic in the 5 GHz band through the use of the SIP (Session Initiation Protocol) and RTP (Real-Time Transport Protocol) protocols, in a laboratory testbed.
Although IEEE 802.11 based wireless local area networks have become more and more popular due to low cost and easy deployment, they can only provide best effort services and do not have quality of service supports for multimedia applications. Recently, a new standard, IEEE 802.11e, has been proposed, which introduces a so-called hybrid coordination function containing two medium access mechanisms: contention-based channel access and controlled channel access. In this article we first give a brief tutorial on the various MAC-layer QoS mechanisms provided by 802.11e. We show that the 802.11e standard provides a very powerful platform for QoS supports in WLANs. Then we provide an extensive survey of recent advances in admission control algorithms/protocols in IEEE 802.11e WLANs. Our survey covers the research work in admission control for both EDCA and HCCA. We show that the new MAC-layer QoS schemes and parameters provided in EDCA and HCCA can be well utilized to fulfill the requirements of admission control so that QoS for multimedia applications can be provided in WLANs. Last, we give a summary of the design of admission control in EDCA and HCCA, and point out the remaining challenges.
The design and simulation of coding schemes, medium access control (MAC), and link-layer protocols for future industrial wireless local area networks can be supported by some understanding of the statistical properties of the bit error patterns delivered by a wireless link (which is an ensemble of transmitter, channel, receiver, modems). The authors present results of bit error measurements taken with an IEEE 802.11-compliant radio modem in an industrial environment. In addition to reporting the most important results, they draw some conclusions for the design of MAC and link-layer protocols. Furthermore, they show that the popular Gilbert/Elliot model and a modified version of it are a useful tool for simulating bit errors on a wireless link, despite their simplicity and failure to match certain measured statistics.
If you’ve been searching for a way to get up to speed on IEEE 802.11n and 802.11ac WLAN standards without having to wade through the entire specification, then look no further. This comprehensive overview describes the underlying principles, implementation details and key enhancing features of 802.11n and 802.11ac. for many of these features the authors outline the motivation and history behind their adoption into the standard. A detailed discussion of key throughput, robustness, and reliability enhancing features (such as MIMO, multi-user MIMO, 40/80/160 MHz channels, transmit beamforming and packet aggregation) is given, plus clear summaries of issues surrounding legacy interoperability and coexistence. Now updated and significantly revised, this 2nd edition contains new material on 802.11ac throughput, including revised chapters on MAC and interoperability, plus new chapters on 802.11ac PHY and multi-user MIMO. An ideal reference for designers of WLAN equipment, network managers, and researchers in the field of wireless communications.
In spite of their limitations, wireless networks are being increasingly used in industrial environments. The electromagnetic phenomena that can occur, along with the interference that may occur due to it being an open medium, mean that fluctuations in latencies are often produced. These drawbacks limit the use of wireless networks for distributed factory applications where timeliness is essential. Recent standards, such as 802.11n, offer some interesting characteristics applicable to factory automation. In particular, QoS support and a very high data rate aids their operation under non-saturation conditions, allowing their satisfactory use as an industrial network. In this paper, the potential of these networks is analyzed in a real world scenario and their performance is compared with an idealized scenario. In both cases the priorities behave as expected, however, the algorithms for an auto-rate functioning perform badly in real world situations, especially in industrial scenarios such as those analyzed here, where the mobility of sources and the interference produced by other sources produce frequent rate changes, leading to a reduction in network performance.
The IEEE 802.11n network main feature is to support high throughput of more than 100Mbps at the MAC layer. To achieve this, the 802.11n Task Group has introduced frame aggregation technique which reduces the overhead and increases the channel utilization efficiency. The MAC layer defines two frame aggregation mechanisms namely the MAC protocol data unit aggregation A-MPDU and MAC service data unit aggregation A-MSDU. A-MPDU is robust against error due to subframes retransmission and large aggregation size, whereas A-MSDU is effective in error free channel due to small headers. A-MPDU has poor performance in erroneous channel because of the absence of sub frames retransmission. It is worth mentioning that some recent researches have enabled the selective retransmission which makes it robust against error. The AMSDU has becomes compatible and able to fulfill the QoS requirements for applications with small frame size such as VoIP, videos as well as interactive gaming. In this paper, we propose A-MSDU real-time scheduler by exploiting the A-MSDU attributes and adopting the idea of enabling retransmission in our aggregation scheduler algorithm to obtain aggregation with small size to support time sensitive applications and satisfying the QoS requirements.
In the last few years, wireless networks have gained significant importance in the context of industrial communication systems [1], where their deployment is bringing several noticeable benefits, ranging from replacement of cables to the connection of devices that cannot be reached by traditional wired systems. These features make the adoption of wireless networks for industrial applications very attractive, and they are envisaged to be deployed even more in the future, either as stand-alone systems or arranged in hybrid (wired/wireless) configurations. Unfortunately, wireless communication systems are often characterized by well-known problems, such as fading, multipath propagation, shadowing, and interference, that have the undesired effect of increasing the bit error rate (BER), resulting in the introduction of delays as well as randomness in packet delivery. Moreover, in the context of industrial communication, these aspects may be exacerbated by the specific nature of the environment. Indeed, the rapid movement of machineries along with the possible presence of electromagnetic interference sources, which are typical of manufacturing sites, may introduce considerable fluctuations of the BER values that contribute to further degradation in communication quality.
In this paper, a design framework of fault-tolerant wireless networked control systems (NCSs) is developed for industrial automation applications. The main objective is to achieve an integrated parameterization and design of the communication protocols, the control and fault diagnosis algorithms aiming at meeting high real-time requirements in industrial applications. To illustrate the design framework, a laboratory wireless fault-tolerant NCS platform is presented.
This paper addresses the performance degradation of multiple-input multiple-output (MIMO) communication systems due to MIMO wireless transceiver radio frequency integrated circuits (RFIC) imperfections. The effects of signal coupling in RF front-end, frequency synthesizer phase noise, and the gain imbalance between different radio paths are investigated. These issues are explored by analytical derivations and results are verified by Monte Carlo simulations. The analytical model achieves a good agreement with the simulation results. The conclusion can serve as a useful reference for MIMO RFIC designers.
The main goal of the IEEE 802.11n standard is to achieve more than 100Mbps of throughput at the MAC service access point. This high throughput has been achieved via many enhancements in both the physical and MAC layers. A key enhancement is frame aggregation which reduces the overheads and increases the channel utilization efficiency. The MAC layer defines A-MSDU and A-MPDU frame aggregations in which MAC overheads are squeezed by aggregating multiple frames into a single large frame before being transmitted. As a consequence of the aggregation, new aggregation headers are introduced and become parts of the transmitted frame. The existence of such headers will have a negative impact on the performance, especially when aggregating frames of small payloads. In this paper, we have analysed the aggregation headers of the 802.11n aggregation schemes and introduced an MSDU frame aggregation that reduces the header's overhead and supports the applications that have a small frame size such as VoIP.
Field-level networks have been one of the keys to modern automation systems. Be it in factory, process, or building automation, networks allow for horizontal and vertical integration of distributed devices and functions. This paper reviews the evolution of field-level networks comprising fieldbus systems, industrial Ethernet, and recent industrial wireless networks. The main focus is on demonstrating the continuity in the development of the three generations that ensured backward compatibility at the expense of radical innovation. Given the wide set of modern communication technologies, this paper then discusses how architectures for future automation networks might look. Particular emphasis is put on hybrid architectures for combined wired/wireless networks. A generic concept for integration of multiple wireless segments will be presented that supports seamless roaming for mobile nodes in industrial environment.
Nowadays, wireless communication technologies are being employed in an ever increasing number of different application areas, including industrial environments. Benefits deriving from such a choice are manifold and include, among the others, reduced deployment costs, enhanced flexibility and support for mobility. Unfortunately, because of a number of reasons that have been largely debated in the literature, wireless systems cannot be thought of as a means able to fully replace wired networks in production plants, in particular, when real-time behavior is a key issue. In this paper, an analysis of the real-time performance that can be achieved in quality-of-service (QoS)-enabled 802.11 networks has been carried out. In particular, a detailed analysis of latencies and packet loss ratios for a typical enhanced distributed channel access (EDCA) infrastructure wireless local area network (WLAN) is presented, obtained through numerical simulations. A number of aspects that may affect suitability for the use in control systems have been taken into account, including the Transmission Opportunity (TXOP) mechanism, the internal architecture of the AP, the use of a time-division multiple access (TDMA)-based communication scheme as well as the adoption of broadcast communications.
In this paper we discuss a selection of promising and interesting research areas in the design of protocols and systems for wireless industrial communications. We have selected topics that have either emerged as hot topics in the industrial communications community in the last few years (like wireless sensor networks), or which could be worthwhile research topics in the next few years (for example cooperative diversity techniques for error control, cognitive radio/opportunistic spectrum access for mitigation of external interferences).
This paper presents a simple two-branch transmit diversity scheme.
Using two transmit antennas and one receive antenna the scheme provides
the same diversity order as maximal-ratio receiver combining (MRRC) with
one transmit antenna, and two receive antennas. It is also shown that
the scheme may easily be generalized to two transmit antennas and M
receive antennas to provide a diversity order of 2M. The new scheme does
not require any bandwidth expansion or any feedback from the receiver to
the transmitter and its computation complexity is similar to MRRC
With the success of wireless technologies in consumer electronics, standard wireless technologies are envisioned for the deployment in industrial environments as well. Industrial applications involving mobile subsystems or just the desire to save cabling make wireless technologies attractive. Nevertheless, these applications often have stringent requirements on reliability and timing. In wired environments, timing and reliability are well catered for by fieldbus systems (which are a mature technology designed to enable communication between digital controllers and the sensors and actuators interfacing to a physical process). When wireless links are included, reliability and timing requirements are significantly more difficult to meet, due to the adverse properties of the radio channels. In this paper, we thus discuss some key issues coming up in wireless fieldbus and wireless industrial communication systems: 1) fundamental problems like achieving timely and reliable transmission despite channel errors; 2) the usage of existing wireless technologies for this specific field of applications; and 3) the creation of hybrid systems in which wireless stations are incorporated into existing wired systems.
IEEE Standard for Information Technology-Telecommunications and Information Exchange Between Systems-Local and Metropolitan Area Networks-Specific Requirements
IEEE Standard for Information Technology-Telecommunications and
Information Exchange Between Systems-Local and Metropolitan Area
Networks-Specific Requirements. Part 11: Wireless LAN Medium
Access Control (MAC) and Physical Layer (PHY) Specifications, IEEE
Standard, Mar. 2012.
Adjacent Channel Interference and Filtering for 56-carrier Signals
- D Hedberg
D. Hedberg, "Adjacent Channel Interference and Filtering for 56-carrier
Signals," IEEE 802.11 document 04/1579r1, 2005.
Joint Proposal Team PHY Simulation Results
- C Aldana
C. Aldana et al., "Joint Proposal Team PHY Simulation Results," IEEE
802.11 TGn document, 06/0067r0, 2006.
Digital data communications for measurement and control – Part 2: Additional profiles for ISO/IEC 8802–3 based communication networks in real–time applications, International Electrotechnical Commission Std
IEC 61784: Digital data communications for measurement and control
– Part 2: Additional profiles for ISO/IEC 8802–3 based communication networks in real–time applications, International Electrotechnical
Commission Std., November 2007.
15) received his Master degree in Automation Engineering from the University of Padova, Italy, in 2014. He is a PhD student with the Department of Information Engineering, University of Padova, Italy. His research interests include wireless networks and real-time industrial communication
- Michele Luvisotto
Michele Luvisotto (S '15) received his Master degree in Automation Engineering from the University
of Padova, Italy, in 2014. He is a PhD student
with the Department of Information Engineering,
University of Padova, Italy. His research interests
include wireless networks and real-time industrial
communication.
Digital data communications for measurement and control -Part 2: Additional profiles for ISO/IEC 8802-3 based communication networks in real-time applications
IEC 61784: Digital data communications for measurement and control
-Part 2: Additional profiles for ISO/IEC 8802-3 based communication networks in real-time applications, International Electrotechnical
Commission Std., November 2007.