Small Wireless Networks Research Articles

무선통신으로 연결되어 연쇄적으로 동작하는 다수의 키네틱 모듈로 구성된 대형 공간을 위한 인스톨레이션 작품 연구

A tendency in large-scale new media installation arts is to build media façades or immersive experience environments using overwhelming amounts and sizes of light displays covering the whole area of an architectural structure, involving the intensive use of capital, materials, and technology. In this research, a different approach was taken with regard to kinetic light art installations, in which lights are used sparingly and are sparsely distributed in the space. In this appropriate installation approach, a minimalistic attitude is taken where the installation is built with simple materials and technology, and modestly takes only the appropriate amount of space at the installation site. In this approach, an installation does not intend to conquer and change the site into something new but only to signify and amplify the identity of the site space. To achieve this goal, the installation takes the form of computational media, generatively adding life to the space in real time and interactively responding to the people living in the space. An installation prototype, Waves, composed of eleven kinetically waving light wands about the size of a hand, was developed. They are distributed in a large, long corridor space and form a large moving wave of light along the space. The light wave has two modes: generative small tides and interactive large waves. To achieve the choreographic functionality, a daisy chain network topology of small wireless networks among three modules in series is used. This type of network is feasible for large-scale installations because it is self-contained and independent of the internet infrastructure, while also allowing for the easy addition of new modules. This research is unique in its approach to overlapping areas of kinetics, light, and network art. The result of this research may provide a platform for future installation works in this area, including the use of other forms of media, other sizes of modules, other methods of interaction with users, and other ways to arrange such modules in space, just to list a few.

Prediction of Packet Loss Rate in Non-Stationary Networks Based on Time-Varying Autoregressive Sequences

Currently, most of the existing link parameter prediction schemes assume that the link state remains constant during the measurement period, making it difficult to capture their time-varying characteristics. To solve this problem, this paper proposes a prediction problem for packet loss rate in a non-stationary network environment. The measurement period is divided into several adjacent time windows, and the packet loss rates measured passively in each time window are regarded as non-stationary time sequences for real-time tracking to obtain the changes in link packet loss rate at a small cost. By analyzing time-varying autoregressive (TVAR) sequences, a scheme for estimating the time-varying coefficient was presented. In addition, a prediction scheme for the packet loss rate in a non-stationary network was proposed based on TVAR sequences. Finally, this paper conducts experiments based on a non-stationary network simulation environment established by the improved Gilbert–Elliot model and a small wireless multi-hop network experiment platform built in reality. Simulation and experimental results show that the prediction scheme of the packet loss rate based on the TVAR sequence can accurately predict the packet loss rate.

Intelligent Control Method of Hoisting Prefabricated Components Based on Internet-of-Things.

Prefabricated buildings are widely used because of their green environmental protection and high degree of industrialization. However, in construction process, there are some defects such as small wireless network coverage, high-energy consumption, inaccurate control, and backward blind hoisting methods in the hoisting process of prefabricated components (PC). Internet-of-Things (IoT) technology can be used to collect and transmit data to strengthen the management of construction sites. The purpose of this study was to establish an intelligent control method in the construction and hoisting process of PC by using IoT technology. Long Range Radio (LoRa) technology was used to conduct data terminal acquisition and wireless transmission in the construction site. The Inertial Measurement Unit (IMU), Global Positioning System (GPS), and other multi-sensor fusion was used to collect information during the hoisting process of PC, and multi-sensor information was fused by fusion location algorithm for location control. Finally, the feasibility of this method was verified by a project as a case. The results showed that the IoT technology can strengthen the management ability of PC in the hoisting process, and improve the visualization level of the hoisting process of PC. Analysis of the existing outdated PC hoisting management methods, LoRa, IMU, GPS and other sensors were used for data acquisition and transmission, the PC hoisting multi-level management and intelligent control.

An Efficient Route Maintenance Protocol for Dynamic Bluetooth Networks

Bluetooth is a widespread technology for small wireless networks that permits Bluetooth devices to construct a multi-hop network called scatternet. Routing in multi-hop dynamic Bluetooth network, where a number of masters and bridges exist creates technical hitches. It is observed that frequent link disconnections and a new route construction consume extra system resources that degrade the whole network performance. Therefore, in this paper an Efficient Route Maintenance Protocol for Dynamic Bluetooth Networks (ERMP) is proposed that repairs the weak routing paths based on the prediction of weak links and weak devices. The ERMP predicts the weak links through the signal strength and weak devices through low energy levels. During the main route construction, routing masters and bridges keep the information of the Fall Back Devices (FBDs) for route maintenance. On the prediction of a weak link, the ERMP activates an alternate link, on the other hand, for a weak device it activates the FBD. The proposed ERMP is compared with some existing closely related protocols, and the simulation results show that the proposed ERMP successfully recovers the weak paths and improves the system performance.

Interference-Aware Cooperative Communication in Multi-Radio Multi-Channel Wireless Networks

There are a lot of recent interests on cooperative communication (CC) in wireless networks. Despite the large capacity gain of CC in small wireless networks with its capability of mitigating fading taking advantage of spatial diversity, cooperative communication can result in severe interference in large networks and even degraded throughput. The aim of this work is to concurrently exploit multi-radio and multi-channel (MRMC) technique and cooperative transmission technique to combat co-channel interference and improve the performance of multi-hop wireless network. Our proposed solution concurrently considers cooperative routing, channel assignment, and relay selection and takes advantage of both MRMC technique and spatial diversity in cooperative wireless networks to improve the throughput. We propose two important metrics, contention-aware channel utilization routing metric (CACU) to capture the interference cost from both direct transmission and cooperative transmission, and traffic aware channel condition metric (TACC) to evaluate the channel load condition. Based on these metrics, we propose three algorithms for interference-aware cooperative routing, local channel adjustment, and local path and relay adaptation respectively to ensure high performance communications in dynamic wireless networks. Our algorithms are designed to be fully distributed and can effectively mitigate co-channel interference and achieve cooperative diversity gain. To our best knowledge, this is the first distributed solution that supports cooperative communications in MRMC networks. Our performance studies demonstrate that our proposed algorithms can efficiently support cooperative communications in multi-radio multi-hop networks to significantly increase the aggregate throughput.

Apply R<sup>+</sup> Tree to Make Hierarchical Cluster Routing with QOS Guarranteed by Multiple Paths and Multicast Routing

In the new era of communication and network technologies, a routing protocol not only operates on some lower levels of a network protocol. It also operates on the application layer the highest-level layer in network protocol stack. So we call this is upper layer routing protocol. But it must be based on lower layers to make routing decisions. But normal routing protocols are used for most static network or rather small wireless networks or not high mobility networks. In mobile ad-hoc networks, nodes move very often and fast, so bandwidth of connection between them can be reduced. Therefore the transmission delay may be increased. The paper aims at purpose to increate QOS routing by hierarchical clustering routing by using R⁺ tree in addition with some advanced techniques multicast routing, multiple paths, use GEN/ BEE/ ANT to optimize routes to transmit data.

Innovating R Tree and Multicast Routing to Make QOS Multiple Paths for Service Based Routing

In the advanced routing of new networks communication and network technologies, it not only operates on some lower levels of a network protocol. But it also operates on some upper layers such as the application layer the highest-level layer in network protocol stack of OSI model. The routing process can be known by a more abstract concept. It can process on many layers on network’s stack of OSI model. So this kind of routing may be called the upper layer routing protocol. As the content based routing, in the service based routing protocol, the information can be classified by categories or service classes. Subscribers and publishers can communicate with each other but they don’t know other’s address. So it is more dynamical in processing and more comfortable for ad-hoc network. However the upper routing must be based on lower layers to make routing decisions. But normal routing protocols are used for most static network or rather small wireless networks or not high mobility networks. In mobile ad-hoc networks, nodes move very often and fast, so bandwidth of connection between them may be reduced. Therefore the transmission delay may be increased. The paper aims at purpose to increate QOS of routing by hierarchical clustering routing by using R+ tree in addition with some advanced techniques multicast routing, multiple paths, use GEN/ BEE/ ANT to optimize routes to transmit data. In R+ tree model, the network’s nodes are managed by Bottom-Up model from leaf nodes to root of the tree. All the leaf nodes, inner nodes and root of this tree are used for two roles: i) Manage a cluster that consists all nodes that have direct connections with this node; ii) Operate as a normal node. The paper mentions: (i) Setup hierarchical clustering network by using R tree structure. (ii) Making multicast tree from some cluster heads for fast routing. (iii) Making optimized route by Ant Colony Optimization.

An experimental study of small multi-hop wireless networks using chirp spread spectrum

Wireless mesh networks have emerged as a viable means of communicating between points that are not within wireless range of each other. There are still, however, a number of challenges involved in designing and implementing such wireless multi-hop networks, particularly with respect to optimising the user throughput. This paper presents some preliminary measurements from an experimental multi-hop wireless networking testbed that has been set up using nodes which utilise Chirp Spread Spectrum (CSS) technology. Multi-hop networks with linear topologies and a maximum of 5 static nodes have been considered. Numerous experiments, mostly indoors, have been performed in which parameters such as the network chain length, the packet size, the logical transmit channel and the transmit power of each node have been varied. The performance of a system with two parallel multi-hop chains was also investigated in which the chains operate simultaneously on either the same or different channels. The end-to-end throughput is observed to fall with increasing chain lengths, typically stabilising for longer chains at values approximately equal to 5---15 % of the single-hop throughput. As the size of the payload is increased, a corresponding linear increase in the throughput is observed. The user throughput also increases with increasing transmit powers at each of the nodes in the chain. However, a trade-off must be made if power and throughput are to be optimised simultaneously.

Wireless network design: a space-filling curve approach

Wireless networks have experienced rapid adoption in recent years. Although installing a small wireless network is relatively easy, deploying a large-scale enterprise wireless infrastructure requir...

Wireless network design: a space-filling curve approach

Wireless networks have experienced rapid adoption in recent years. Although installing a small wireless network is relatively easy, deploying a large-scale enterprise wireless infrastructure requires careful planning, so as to minimise cost while meeting various Quality of Service (QoS) requirements. Existing research has mainly focused on formulating simpler mathematical models or finding solution approaches. The major difficulty in these methods is in the numerous measurements, of signal strengths between possible user and base-station (or access point) locations, required to provide the input data. In this paper, we propose an efficient Space-Filling Curve (SFC)-based heuristic for solving the network design problem. The SFC heuristic is easy to implement, fast in execution and can provide good first-cut solutions. Most importantly, the SFC's property of preserving 'nearness' among points makes the solution feasible and sound, and thereby reduces the signal strength measurements effort needed.

Optimal Transmission Radius for Flooding in Large Scale Sensor Networks

One of the principal characteristics of large scale wireless sensor networks is their distributed, multi-hop nature. Due to this characteristic, applications such as query propagation rely regularly on network-wide flooding for information dissemination. If the transmission radius is not set optimally, the flooded packet may be holding the transmission medium for longer periods than are necessary, reducing overall network throughput. We analyze the impact of the transmission radius on the average settling time--the time at which all nodes in the network finish transmitting the flooded packet. Our analytical model takes into account the behavior of the underlying contention-based MAC protocol, as well as edge effects and the size of the network. We show that for large wireless networks there exists an intermediate transmission radius which minimizes the settling time, corresponding to an optimal tradeoff between reception and contention times. We also explain how physical propagation models affect small wireless networks and why there is no intermediate optimal transmission radius observed in these cases. The mathematical analysis is supported and validated through extensive simulations.

Modeling Dynamic Channel-Allocation Algorithms in Multi-BS TDD Wireless Networks With Internet-Based Traffic

Future time-division-duplex (TDD) systems operating over small wireless networks will utilize intelligent base station (BS)-coordinated dynamic channel-allocation algorithms in order to support high-bandwidth asymmetric traffic in adjacent cells. In this paper, we use extensive measurements of wireless Internet traffic from a large 802.11b network to create two random traffic models. One model, called binomial, is memoryless and the other, called dynamic, is based on an event-driven Markov state model with bidirectional flows and deterministic residence times. We then develop a two-BS two-zone wireless TDD interference model that describes the spatial features of interference between cochannel mobile stations (MSs) in adjacent BSs. This is a simplified precursor to more sophisticated models for multiple BSs and/or multisector BSs. We present a set of candidate TDD channel-allocation algorithms, which vary in their level of time-slot coordination and intelligent allocation between BSs. Lastly, we combine the three components (i.e., traffic models, interference models, and channel-allocation algorithms) to demonstrate the capacity for evaluating dynamic channel-allocation algorithms in realistic interference and Internet traffic scenarios. The results show that, for active MSs, the dynamic traffic model has a higher number of packet requests per time frame than the binomial traffic model, given the same mobile activity factor. Additionally, fixed channel-allocation algorithms generally perform much worse than pseudorandom and intelligent BS-coordinated algorithms, especially for asymmetric BSs. The pseudorandom algorithm performs well at low traffic, but suffers from severe interference blocking at high traffic. The intelligent BS-coordinated algorithm performs best, as it avoids MS-to-MS interference blocking from nearby users in adjacent cells and maximizes the overall throughput by attempting to allocate up- and downlink packet requests in corresponding time slots matched to the incoming uplink-downlink traffic demand for each time frame.

Bluetooth's slow dawn

Bluetooth was developed initially by Ericsson as a short-range cable replacement for linking portable consumer electronic products, but it can also be adapted for printers, fax machines, keyboards, toys, games, and virtually any other digital consumer application. The technology provides a mechanism for forming small wireless networks of Bluetooth-equipped products on an ad hoc basis. It can also serve as a wireless bridge to existing data networks. However, hype has given way to hard work as expectations for the mini radio network encounter nettlesome interoperability issues.