Statistical Delay Bound for WirelessHART Networks

In this paper we provide a performance analysis framework for wireless industrial networks by deriving a service curve and a bound on the delay violation probability. For this purpose we use the (min,x) stochastic network calculus as well as a recently presented recursive formula for an end-to-end delay bound of wireless heterogeneous networks. The derived results are mapped to WirelessHART networks used in process automation and were validated via simulations. In addition to WirelessHART, our results can be applied to any wireless network whose physical layer conforms the IEEE 802.15.4 standard, while its MAC protocol incorporates TDMA and channel hopping, like e.g. ISA100.11a or TSCH-based networks. The provided delay analysis is especially useful during the network design phase, offering further research potential towards optimal routing and power management in QoS-constrained wireless industrial networks.Comment: Accepted at PE-WASUN 201

Towards new routing solutions for wireless industrial networks

Routing in wireless multi-hop networks has been addressed by numerous research works so far. However, the increased usage of Machine-to-Machine (M2M) and industrial communication has set even higher goals regarding Quality-of-Service (QoS) and energy consumption. There are hardly works which combine both reliable and in time packet delivery as well as energy-efficiency. In this PhD thesis we are interested in energy-efficient routing solutions under QoS constraints such as Bit-Error-Rates (smaller than 10 to the power of minus 5) and delays not bigger than several milliseconds. By means of stochastic network calculus and Gilbert-Elliott (GE) model, physical channel characteristics will be embedded in the performance definition of network routes to enable additional energy management

Performance analysis of wireless industrial networks - challenges and trends: Presentation held at the ETAI 2018 Conference, 20.-22.09.2018, Struga, Mazedonien

The increased deployment of wireless networks in industrial settings enhances the need to provide performance guarantees while at the same time demands resource-efficient network operation. Especially for multi-hop wireless networks, characterized by fading channels and queueing effects, an appropriate analytical framework to compute an end-to-end statistical delay guarantee is needed. Moreover, a transmit-power-efficient packet transmission is especially important in energy-limited networks or industrial settings with high coexistence management requirements. This talk discusses the research challenges for such scenarios and elaborates how the mentioned aspects can be combined in order to obtain analytical formulation of multi-hop network performance under delay constraints. It further presents a delay bound-based optimal power allocation for heterogeneous wireless multi-hop networks. Typical industrial applications which would benefit of such performance analysis in the process of network design are discussed in addition. The obtained results are illustrated via numerical examples, mostly for TSCH-like networks, for which the resulting network lifetime duration is compared towards a system optimum gained via simulations

End-to-End Performance Analysis for Industrial IEEE 802.15.4e-based Networks

In this extended abstract we present an analytical solution for the end-to-end delay bound for multi-hop IEEE 802.15.4e-based networks. We base our derivation on the stochastic network calculus principles in order to provide performance guarantees for wireless industrial sensor networks. We validate the derived solution by simulations. Further, we show that the bound is convex, which, together with its monotonicity in the average SNR on the links, enables design of algorithms for optimal transmit power allocation. These two aspects: optimizing network operation while at the same time providing end-to-end delay guarantees, are of great importance for the development of reliable, stable and power-efficient wireless industrial networks

Network-Calculus-Based Approach for Optimal Transmit Power Allocation in Wireless Industrial Multi-Hop Networks: Presentation held at ITG Workshop on Cellular Internet of Things, 01.12.2017, Munich

The talk presents a closed-form expression for the end-to-end delay bound in wireless multi-hop heterogeneous networks. The service characterization of the wireless channel is represented by the IEEE 802.15.4-based formula on the bit error rate. The convex behavior of the delay bound enables the design of a power-minimization algorithm, which defines the minimal possible transmit power per node satisfying at the same time the end-to-end QoS requirements by the application, given in form of statistical delays. The algorithm maximizes the network lifetime and prevents power overprovisioning. The talk presents several numerical results which confirm the potential of network-calculus-based optimization algorithms, showing that such solution can provide performance guarantees in wireless industrial sensor networks, while at the same time enabling long battery lifetime

Energy-Efficient Multi-Hop Transmission for Machine-to-Machine Communications

Emerging machine-to-machine communication scenarios are envisioned to deal with more stringent quality-of-service demands. This relates mainly to outage and latency requirements, which are for example for safety-critical messages quite different than for traditional applications. On the other hand, it is widely accepted that machine-to-machine communication systems need to be energy-efficient because of the widespread use of battery-powered devices, but also due to their huge deployment numbers. In this paper, we address these issues with respect to multi-hop transmissions. Specifically, we deal with minimizing the consumed energy of transmitting a packet with end-to-end outage and latency requirements. We account for the cases in which the system can utilize solely average channel state information, or in addition obtain and profit from instantaneous channel state information. The developed solution is based on convex optimization. It is shown numerically that despite accounting for the energy consumption of acquiring instantaneous channel state information, especially as the outage and latency requirements become tough, it is by up to 100 times more energy efficient to convey a packet with instantaneous than with average channel state information.QC 20131209</p

Power Minimization for Industrial Wireless Networks under Statistical Delay Constraints

Energy efficiency is a very important aspect of modern communication systems. In particular, industrial appli-cations, that deploy wireless machine-to-machine communication and process automation, demand energy-efficient communication in order to prolong battery lifetime and reduce inter-node interference, while maintaining a predefined probabilistic delay bound. In this work, we propose an algorithm that minimizes the transmit power in a WirelessHART network under statistical delay constraints. We achieve this by utilizing a recently developed network calculus approach for wireless networks performance analysis. The evaluation of the algorithm shows that it reaches quasi-minimal power settings within a few iterations.QC 20150331</p

Bound-based power optimization for multi-hop heterogeneous wireless industrial networks under statistical delay constraints

The noticeably increased deployment of wireless networks for battery-limited industrial applications in recent years highlights the need for tractable performance analysis methodologies as well as efficient QoS-aware transmit power management schemes. In this work, we seek to combine several important aspects of such networks, i.e., multi-hop connectivity, channel heterogeneity and the queuing effect, in order to address these needs. We design delay-bound-based algorithms for transmit power minimization and network lifetime maximization of multi-hop heterogeneous wireless networks using our previously developed stochastic network calculus approach for performance analysis of a cascade of buffered wireless fading channels. Our analysis shows an overall transmit power saving of up to 95% compared to a fixed power allocation scheme in case when the service is modeled via a Shannon capacity. For a more realistic set-up, we evaluate the performance of the suggested algorithm in a WirelessHART network, which is a widely used communication standard for industrial process automation applications. We find that link heterogeneity can significantly reduce network lifetime when no efficient power management is applied. Using extensive simulation study we further show that the proposed bound-based power allocation performs reasonably well compared to the real optimum, especially in the case of WirelessHART networks

On the recursive nature of end-to-end delay bound for heterogeneous wireless networks

Multi-hop wireless networks are increasingly becom-ing more relevant to current and emerging wireless networkdeployment. The need for understanding the performance of suchnetworks in order to be able to provide quantifiable end-to-endquality of service is apparent. Until recently, only asymptoticresults that describe the scaling of the delay in the size of thenetwork under numerous conformity conditions were available.Recently, a new methodology for wireless networks performanceanalysis based on stochastic network calculus was presented[1]. This methodology enables the computation of end-to-endprobabilistic delay bound of multi-hop wireless networks interms of the underlying fading channel parameters. However,the approach assumes identically distributed channel gain whichapplies to a very specific class of networks. In this work, we seekto develop an end-to-end probabilistic delay bound for multi-hop wireless networks with non-identically distributed channelgains. We show that the delay bound for such networks can becomputed recursively. We validate the resulting bound by meansof simulation and discuss various numerical examples.QC 20150923</p

Energy-efficient multi-hop transmission for machine-to-machine communications

Emerging machine-to-machine communication scenarios are envisioned to deal with more stringent quality-of-service demands. This relates mainly to outage and latency requirements, which are for example for safety-critical messages quite different than for traditional applications. On the other hand, it is widely accepted that machine-to-machine communication systems need to be energy-efficient because of the widespread use of battery-powered devices, but also due to their huge deployment numbers. In this paper, we address these issues with respect to multi-hop transmissions. Specifically, we deal with minimizing the consumed energy of transmitting a packet with end-to-end outage and latency requirements. We account for the cases in which the system can utilize solely average channel state information, or in addition obtain and profit from instantaneous channel state information. The developed solution is based on convex optimization. It is shown numerically that despite accounting for the energy consumption of acquiring instantaneous channel state information, especially as the outage and latency requirements become tough, it is by up to 100 times more energy efficient to convey a packet with instantaneous than with average channel state information.QC 20131209</p