- Communication-efficient Embedded FFT Processing for Acoustic Telemetry in LPWAN-based Beehive Monitoring Systems
- Dual Wide-band Microstrip Antenna for Wireless Communication Systems
- Network Threat Detection in IaaS Environments Based on Flow Log Data
- Machine Learning-based Automatic Modulation Classification for 5G-Advanced and 6G Waveforms: Robust Identification Under Realistic Channel Impairments
No. 2 (2009)
Published:
2009-06-30
Full Issue
ARTICLES FROM THIS ISSUE
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Percolation Driven Flooding for Energy Efficient Routing in Dense Sensor Networks
Abstract
Simple flooding algorithms are widely used in ad hoc sensor networks either for information dissemination or as building blocks of more sophisticated routing protocols. In this paper a percolation driven probabilistic flooding algorithm is proposed, which provides large message delivery ratio with small number of sent messages, compared to traditional flooding. To control the number of sent messages the proposed algorithm uses locally available information only, thus induces negligible overhead on network traffic. The performance of the algorithm is analyzed and the theoretical results are verified through simulation examples.
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Multiobjective Design of Wireless Ad Hoc Networks: Security, Real-Time and Lifetime
Abstract
This paper deals with the tradeoffs between security, real-time and lifetime performance. Due to the multihop nature of communication wireless ad hoc networks are very vulnerable to attacks. Malicious nodes included in a routing path may misbehave and organize attacks such as black holes. Scaling the number of hops for a packet delivery we trade off energy efficiency against security and real-time communication. To study the multihop communication we propose a hierarchical communication model. The REWARD (receive, watch, redirect) algorithm for secure routing is employed as a main example for corrective actions. Symmetrical routing is a distinguish feature of protocols such as REWARD and we outline the threshold of conflict between power-efficient partitioning of communication links and symmetrical routing.
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A Method of Mobile Base Station Placement for High Altitude Platform Based Network with Geographical Clustering of Mobile Ground Nodes
Abstract
High altitude platforms (HAPs) such as unmanned aerial vehicles (UAVs) which can be deployed as stratospheric infrastructures enable a sort of new configurations of wireless networks. Ground nodes must be clustered in multiple sets and one dedicated UAV is assigned to each set and act as an mobile base station (MBS). For the intra-set nodes, UAVs must communicate each other in order to establish network links among intra-set nodes. Here we find a geographical clustering problem of networking nodes and a placement problem of MBSs. The clustering technique of mobile ground nodes can identify the geographical location of MBSs as well as the coverage of MBSs. In this paper we proposed a clustering mechanism to build such a configuration and the effectiveness of this solution is demonstrated by simulation. For a selected region with a relatively big island, we modeled mobile ground nodes and showed the result of dynamic placement of MBSs by our clustering algorithm. The final results will be shown graphically with the mobility of ground nodes as well as the placement of MBSs.
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A Framework for Detection of Selfishness in Multihop Mobile Ad Hoc Networks
Abstract
The paper discusses the need for a fully-distributed selfishness detection mechanism dedicated for multihop wireless ad hoc networks which nodes may exhibit selfish forwarding behavior. The main contribution of this paper is an introduction to a novel approach for detecting and coping with the selfish nodes. Paper describes a new framework based on Dempster-Shafer theory-based selfishness detection framework (DST-SDF) with some mathematical background and simulation analysis.
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Modulo N Backoff Scheme for Effective QoS Differentiation and Increased Bandwidth Utilization in IEEE 802.11 Networks
Abstract
The paper presents a new modulo N channel access scheme for wireless local area networks (WLANs). The novel solution derives from the distributed coordination function (DCF) of the IEEE 802.11 standard, further elaborated as enhanced distribution channel access (EDCA) by the 802.11e draft specification. The main innovation concerns improvement of the binary exponential backoff scheme used for collision avoidance in 802.11 networks. The most appealing feature of the new modulo N backoff scheme is that it outperforms the original 802.11 solution in terms of channel utilization ratio under any traffic conditions. Furthermore, the modulo N proposal can be naturally augmented with QoS differentiation mechanisms like 802.11e extensions. The prioritized modulo N scheme achieves better throughput-delay characteristics for multimedia traffic when compared with the original 802.11e proposal. At the same time, the new solution retains backward compatibility and includes all features which have made IEEE 802.11 networks extremely popular nowadays.
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Empirical Season’s Fadings in Radio Communication at 6 GHz Band
Abstract
This paper covers unavailability of line-of-sight radio links due to multipath propagation. Multipath fading in the atmosphere is not permanent phenomenon. The five year investigation results of the received radio signal fading in the radio links and their season empirical distributions are presented.
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Laser Beam Attenuation Determined by the Method of Available Optical Power in Turbulent Atmosphere
Abstract
This work is focused on the atmospheric turbulence effect and a new method for determining optical signal attenuation caused by turbulence is presented here. A new method of power budget of optical links comes from optical intensity distribution in a laser beam after the beam passed through turbulent atmosphere. Results given by this method are compared with Rytov approximation which is nowadays the most frequently used method for determining turbulent attenuation. Results for communication wavelength of 850 nm and 1550 nm are presented as well as the results for a wavelength of 633 nm.
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The Design of 4×4 Multimode Interference Coupler Based Microring Resonators on an SOI Platform
Abstract
This paper would like to propose a novel microring resonator based on 4 × 4 multimode interference (MMI) couplers. The device acts as two separate microring resonators just in one structure. The transfer matrix method and the three dimensional beam propagation method (3D-BPM) are used to verify the working principle of the device. The device is then designed on silicon on insulator (SOI) technology. This device may be a very promising building block for optical switches, filters, add-drop multiplexers, delay lines and modulators.
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Linux Scheduler Improvement for Time Demanding Network Applications, Running on Communication Platform Systems
Abstract
Communication platform systems as, e.g., advanced telecommunication computing architecture (ATCA) standard blades located in standardized chassis, provides high level communication services between system peripherals. Each ATCA blade brings dedicated functionality to the system but can as well exist as separated host responsible for servicing set of task. According to platform philosophy these parts of system can be quite independent against another solutions provided by competitors. Each system design can be different and can face with many computer systems design problems. One of the most difficult design problems to solve is system integration with a set of components running on different operating system levels. This paper presents Linux scheduler improvement possibility to make user space application classified as time demanding (required to be serviced by CPU in given amount of time) running in user space together with complicated kernel software structure in the system.
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Simple Dynamic Threshold Decryption Based on CRT and RSA
Abstract
In the paper we present a simple threshold decryption system based on the RSA cryptosystem. Our model avoids the application of the Shamir secret sharing protocol and is based only on the Chinese reminder theorem. The flexibility in the threshold level is attained due to the suitable preparation of the input data. The second part of the article describes a modification of the basic model, which admits the sender’s impact on the choice of the real receiver’s group.
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Generating Pseudorandom S-Boxes – a Method of Improving the Security of Cryptosystems Based on Block Ciphers
Abstract
The paper presents a general framework for improving the security of the cryptosystem based on the symmetric block cipher. The main idea is based on possibility of chancing substitution boxes (called S-boxes) in encryption/decryption algorithm. In order to make it possible, it is necessary to generate identical boxes by an encryption and decryption party. This is the main reason, why deterministic methods of generating substitution boxes based on the pseudorandom sequences will be presented.
