1,721,045 research outputs found
Joint scheduling and routing with power control for centralized wireless sensor networks
No full textWe consider a TDMA-based multi-hop wireless sensor network, where nodes send data to a sink, which is aware of received powers at all receivers; the sink is responsible for creating the network topology and assigning time slots to links. Under this centralized approach, we propose two algorithms that jointly define the tree topology connecting nodes to the sink, and assign time slots, avoiding any packet loss. In contrast with previous works, the proposed algorithms accurately account for interference effects; when evaluating the signal-to-interference ratio to establish the tree and schedule transmissions, we consider the sum of all actual interfering signals, a fact of relevance for networks with increasing number of nodes. Optimal selection of transmit powers, minimizing energy consumption, is also applied. Our algorithms are compared to a benchmark solution and other proposals from the literature; it is shown that they bring to better radio resource utilization, higher throughput and lower energy consumption, while keeping the average delay limited
Performance Characterization of Digital Transmission Systems with Cochannel Interference
No full textThis paper presents a general methodology for performance characterization of digital transmission systems in the presence of cochannel interference, as a function of the actual number of interferers (ranging from zero to infinity). The bit error probability in time-invariant channels and outage probability in time-varying quasi-stationary channels are discussed. More precisely, a general approach to an outage probability definition based on the concept of the outage domain is introduced. This allows the discussion of the relation to the other definitions which have appeared in the literature and the proposal of some new more accurate methods for the evaluation of outage probability. A suitable comparison between exact evaluation, the well-known Gaussian approximation, and the other new approaches proposed in this paper, is carried out to evaluate performance, bit error probability is suitably obtained for linearly modulated signals by adopting a semianalytical approach, and for nonlinear (e.g., continuous phase) modulation signals, by means of simulation. Finally, as an example, the different approaches to derive performance discussed in the paper have been applied to a linear microcellular scenari
Introduction to Selected Extended Papers from PIMRC’2018
No full textIntroduction to Selected Extended Papers from PIMRC’201
Semi-analytical Evaluation of Outage Probability for Pico and Microcellular Mobile Radio Systems with Correlated Shadowing
No full textOutage probability due to interference and spectrum efficiency for pico- and microcellular mobile radio systems, are considered. A general expression for evaluating outage probability in the presence of a Rician channel both for the useful signal and the interferers, is presented: moreover, a Monte-Carlo simulation method for evaluating the effects of correlated shadowing is applied
A 2.4 GHz LoRa-Based Protocol for Communication and Energy Harvesting on Industry Machines
Full text linkThe fourth industrial revolution is paving the way for Industrial Internet of Things applications where large number of wireless nodes, equipped with sensors and actuators, monitor the production cycle of industrial goods. This paper proposes and analyses LoRaIN, a network architecture and MAC-layer protocol thought for on-demand monitoring of industrial machines. Our proprietary system is an energy-efficient, reliable and scalable solution, where the protocol is built on top of LoRa at 2.4 GHz. Indeed, the low-power characteristics of LoRa allow to reduce energy consumption, while Wireless Power Transfer is used to recharge batteries, avoiding periodic battery replacement. High reliability is obtained through the joint use of Frequency and Time Division Multiple Access. A dynamic LoRaIN scheduler manages the communication and recharging phases depending on the tasks assigned to the nodes, as well as the number of monitoring devices. Performance is measured in terms of network throughput, energy consumption and latency. Results demonstrate that the proposed solution is suitable for monitoring applications of industry machines
OCDMA: a MAC Protocol for Industrial Intra-machine TeraHertz Network
Full text linkThis paper considers an industrial machine, where wireless sensor nodes (denoted as tags or nodes) support control applications. This scenario poses very challenging communication requirements: hundreds of tags per cubic meter can provide an overall offered throughput of tens of Gbit/s; at the same time, control applications require a latency of less than 0.1 ms. To fulfill them, this work proposes an Orthogonal Chirp Division Multiple Access (OCDMA) scheme to be used in the TeraHertz (THz) frequency band. With THz communications, even at short distances, propagation delays can be of the same order of magnitude as the packet transmission time. This requires proper consideration of such delays in the protocol design and performance evaluation. This paper mathematically derives network throughput and latency of the proposed protocol, comparing it to benchmarks; two scenarios are considered, where tags are in fixed positions or move. Results show that OCDMA outperforms the two benchmark protocols, Aloha and Polling, for static and crowded networks, and the performance is compatible with the communication requirements of industrial control applications
Partial compensation signal-level-based up-link power control to extend terminal battery duration
No full textPower control (PC) techniques have been studied for years with the aim of reducing interference and allowing efficient battery energy management. Among PC algorithms, those based on the signal-level (not on cochannel interference) show good characteristics in terms of network stability and provide optimum downlink performance when a half-compensation scheme is used instead of a full-compensation algorithm. This work is concerned with partial (including the full and half cases) compensation signal-level-based PC algorithms and their impact on battery duration of mobile terminals, i.e., the uplink is investigated. A time division multiple access (TDMA)-based cellular system is considered. The effect of a slow PC, i.e., following only slow channel fluctuations, on the average transmitted power of mobile terminals is evaluated through a completely analytical model; both ideal and nonideal PC are considered. Starting from suitable requirements on radio coverage, we show that a half-compensation PC scheme is often a good choice for extending terminal battery life (thus, also reducing health risks
On the Capacity of Slotted Aloha with Rayleigh Fading: the Role Played by the Number of Interferers
No full textThe role played by the number of interferers and the modulation choice in the performance of slotted Aloha networks with Rayleigh fading is investigated and discussed; the case of multiple transmitted power classes is also considered. A new capture model which takes the number of actual interferers into account is proposed. The network capacity is analytically estimated, and significant differences (depending on the modulation scheme) are found with respect to previously published results carried out by means of more common (and less accurate) capture models, also when the case of different transmitted power classes is considere
The role of ground-to-air handovers in B5G UAV-aided mobile networks
No full textIn this paper, we study the potential advantages of integrating Unmanned Aerial Vehicles (UAVs) equipped with Base Stations, with a terrestrial mobile network infrastructure. In particular, our main focus here lays on handover and its role in B5G (Beyond 5G) networks. We consider a scenario where multiple UAVs and terrestrial bases jointly provide service to mobile ground users. By combining the UAV dynamic trajectory and radio access procedures, we investigate the impact and network performance of ground-to-air handovers. With respect to previous papers, we discuss how to optimise the UAV segment of the network. Final results show that the UAV needs to adjust its speed, height and antenna radiation angle to improve network performance
Performance Evaluation of a Bluetooth-Based WLAN Adopting a Polling Protocol under Realistic Channel Conditions
No full textEven if Bluetooth has not been specifically designated for WLANs (Wireless Local Area Networks) and the interconnection of computers, the possibility of establishing low-cost wireless connections makes this technology attractive for this kind of context also. In this paper we assess, by means of a simulative approach that takes the complete physical and MAC level aspects into account, the performance of a Bluetooth-based WLAN adopting a roll-call polling protocol under realistic channel conditions, that is, in the presence of the typical impairments of indoor wireless communications (fading, etc); moreover, we propose an analytical formulation to derive the maximum throughput offered by a Bluetooth link and we suggest a call admission control technique based on the previous analytical considerations
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