Int. J. Wirel. Opt. Commun.最新文献

{"title":"Guest Editorial: \"Special Issue: Ultra-Wideband Antennas and Propagation\"","authors":"Zhi Ning Chen, Keren Li","doi":"10.1142/S0219799506000533","DOIUrl":"https://doi.org/10.1142/S0219799506000533","url":null,"abstract":"In February 2002, the Federal Communications Commission (FCC) released the unlicensed frequency band of 3.1–10.6 GHz for commercial applications. This has greatly spurred the development of commercial ultra-wideband (UWB) communications systems and devices worldwide. Due to the extremely wide spectrum, the UWB-based systems have the potential to achieve high data rate in the order of 500Mbps up to even Gbps. On the other hand, in the low power and low data rate applications, the research and development effort has been focused on high accuracy localization or positioning systems. In UWB technology, to cater for the increase in transmission speed, reduction in power consumption and transceiver cost, a comprehensive investigation of UWB system issues, RF circuitry, antenna design, and propagation characteristics must be carried out. This Special Issue with eight strictly selected papers presents advanced progress in research and development of Antennas and Propagation for promising UWB applications. We have to mention here that the response from the community to this Special Issue is pretty good after the call for paper was announced for only six months, and we received 16 very high quality papers. The contributions cover almost all topics related to UWB antennas and propagation. Unfortunately, due to the limited space available, we have to make a very hard decision to include only eight of them in this Special Issue. Some of them have been recommended for possible publication as regular papers in International Journal of Wireless and Optical Communications in the future. The major content of the eight papers in this Special Issue can be summarized below. The first paper entitled “Antenna Time Domain Planar Near-field Measurement System” by N. Wang et al. reports on the advanced progress in development of time-domain near-field measurement. Such time-domain near-field measurement technology is the key to obtain antenna under test’s (AUT) far-field radiation patterns in frequency domain by Fourier transforming the far-field in time domain which is the outcome of transform of near-field far-field and time domain probe correction. The work started in 1996 and has been focused on developing software for general measurement system design, such as system control, time domain sampling, frequency domain probe correction, near-field far-field transform, results correction and analysis. In 2003, the authors built the first antenna time","PeriodicalId":185917,"journal":{"name":"Int. J. Wirel. Opt. Commun.","volume":"66 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130699052","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Development of an Omnidirectional and Low-VSWR Ultra Wideband Antenna","authors":"T. Taniguchi, Akihide Maeda, Takehiko Kobayashi","doi":"10.1142/S0219799506000442","DOIUrl":"https://doi.org/10.1142/S0219799506000442","url":null,"abstract":"This paper reports an omnidirectional-in-azimuth and low voltage-standing-wave-ratio (VSWR) ultra-wideband (UWB) monopole antenna that we constructed as a prototype for the Federal Communications Commission-approved UWB frequency band (3.1–10.6 GHz). Most wideband antennas (e.g. double-ridged waveguide horn, monocone antenna) do not simultaneously meet omnidirectional and low-VSWR requirements, essential for some UWB measurement applications. The antenna consists of a circular ground plane and a teardrop that is defined as a combination of a finite cone and a sphere inscribed inside the cone at the cone's base. This antenna can be considered either as a rounded finite monocone antenna or as a simplified volcano smoke antenna. Assuming 50-Ω excitation, the optimum half-cone angle was searched to minimize the maximum VSWR between 3.1 and 10.6 GHz and found to be around 48°. A prototype antenna was constructed and its VSWR and radiation characteristics were measured. The prototype antenna demonstrated omnidirectional radiation and low VSWR (< 1.3) between 3 and 20 GHz. Performance comparison was made between this antenna and other representative wideband antennas: double-ridged-waveguide horn antenna, meander line antenna, and log-periodic dipole array antenna. The 3-antenna method was used to achieve high accuracy in the absolute gain measurements.","PeriodicalId":185917,"journal":{"name":"Int. J. Wirel. Opt. Commun.","volume":"63 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121109220","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Using UWB Measurements for Statistical Analysis of the Ranging Error in Indoor Multipath Environment","authors":"B. Alavi, K. Pahlavan, N. Alsindi, Xinrong Li","doi":"10.1142/S0219799506000454","DOIUrl":"https://doi.org/10.1142/S0219799506000454","url":null,"abstract":"In this paper we use UWB measurements for bandwidths up to 3 GHz to present a framework for statistical modeling of the indoor radio channel propagation characteristics that are pertinent to precise indoor geolocation using time-of-arrival (TOA) estimations. Accuracy of indoor geolocation systems relies on the strength and TOA of the direct path (DP) in the channel profile. Based on UWB measurements in a typical office building, we introduce empirical models for the path-loss and TOA of the DP. Path-loss model for the DP is used to analyze the occurrence of the undetected direct path (UDP) conditions which cause large errors in indoor geolocation systems. We then introduce a novel statistical model for the ranging or distance measurement error (DME) which is needed for comparative performance evaluation of the indoor positioning algorithms. The DME is a function of the bandwidth of the system, occurrence of the UDP conditions, and the distance between the transmitter and the receiver.","PeriodicalId":185917,"journal":{"name":"Int. J. Wirel. Opt. Commun.","volume":"94 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114566085","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A New Approach for Modeling Local Selective Connectivity and Maintaining Isolated Regions in Ad Hoc Networks","authors":"M. Borschbach","doi":"10.1142/S0219799506000363","DOIUrl":"https://doi.org/10.1142/S0219799506000363","url":null,"abstract":"The major prerequisites for successful wireless ad hoc networking are an almost homogeneous distribution of a non-trivial number of nodes and the determination of an almost ideal selective connectivity of these nodes in the network. To give a basic characterization of network connectivity, an ad hoc network model based on planar graphs is introduced. According to this underlying mathematical network description, the features of homogeneous connectivity for ad hoc networks are defined. The network model definitions of a connected, a simple connected, a strict connected, a multiple connected and a strong connected network have an iterative foundation on the meta set of the formal network description and the fulfilled local connectivity requirements. The degree of connectivity of each node and the intensity of connectivity of the network itself is maintained by the multiple paths existing at a time. Due to a specific physical layer ratio of wireless capacity utilization and the average number of independent paths, a condition of isolation provides the opportunity to maintain isolated areas in any given ad hoc network distribution. To support identified isolated regions is a main goal of a hybrid transfer network. According to the common underlying mathematical model of ad hoc networks introduced, a selective network model is defined to analyze local node connectivity. Based on a system architecture with a predetermined number of independent and simultaneous links of each network node, the different optimization degrees of the selection of neighbors are presented. A higher relaying efficiency gives the main opportunity for an ad hoc net to be an essential part of a future networking system. The efficiency of a selective network topology is compared to pure range controlled topology.","PeriodicalId":185917,"journal":{"name":"Int. J. Wirel. Opt. Commun.","volume":"51 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117349600","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Bright and Dark solitary Wave Solution for Higher Order NLS equation with cubic and quintic Effects","authors":"G. Narayanasamy","doi":"10.1142/S0219799506000417","DOIUrl":"https://doi.org/10.1142/S0219799506000417","url":null,"abstract":"Using the coupled amplitude phase technique, we find general analytical bright solitary wave solution for the higher order nonlinear Schrudinger equation with cubic-quintic terms which describes the effects of femto-second optical soliton pulse propagation in the non-Kerr medium. Also, we find the analytical dark soliton solution by Jacobin elliptical function.","PeriodicalId":185917,"journal":{"name":"Int. J. Wirel. Opt. Commun.","volume":"3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131230491","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A Scheduling Algorithm in a Core Optical Router with Heterogeneous Traffic","authors":"R. Hu, R. Best, Y. Qian, Mingzhou Jin","doi":"10.1142/S0219799506000351","DOIUrl":"https://doi.org/10.1142/S0219799506000351","url":null,"abstract":"Recent advances in optical networking reveal that large-scale optical networks supporting heterogeneous traffic may soon become economical as the underlying backbone in wide area networks, in which optical routers play a key role. One big challenge in designing future large-scale optical systems is packet scheduling for the core optical routers. The optical router is a delay system with packets waiting at its ingress queues. A scheduler is necessary to allocate resources so that delay and jitter sensitive real-time traffic can be served with higher priority than the non-delay sensitive traffic. The system capacity should also be efficiently utilized. This is achieved by a prioritised non-blocking scalable scheduling algorithm developed in this paper. The proposed algorithm is based on a heuristic approximation of a Linear Integer Programming model. The performance evaluations in a multi-service high capacity core optical router show that the heuristic solution is close to the optimal solution most of the time, yet it is much easier to implement.","PeriodicalId":185917,"journal":{"name":"Int. J. Wirel. Opt. Commun.","volume":"18 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124648544","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A Hybrid Scheme for Handover in ATM-Based Personal Communication Network","authors":"B. K. Gupta, M. Lal, S. Sharma","doi":"10.1142/S0219799506000387","DOIUrl":"https://doi.org/10.1142/S0219799506000387","url":null,"abstract":"In a Personal Communication Networks (PCN), the covered geographical area is typically partitioned into a set of microcells. Each microcell has a Base Station (BS) to exchange radio signals with wireless mobile terminals. Due to the limited range of wireless transceivers, mobile users can communicate only with BSs that reside within the same microcell at any instance. The number of handoffs/handovers during a call will increase as the cell radii decrease, thus affecting the Quality of Service (QoS). Frequent handoff in wireless/mobile networks introduces a new paradigm in the area of network congestion and admission control. The increase in processing load due to demand for service and fast handoffs to mitigate the propagation effect, a high speed backbone network for the PCN to connect BS is required. The ATM technology, which has recently emerged to be a predominant switching technology, is suited to be an infrastructure to interconnect the BSs of the PCN. To support network-wide handoff, new and handoff call requests will compete for connection resources in both the mobile and backbone networks. Handoff calls require a higher congestion related performance, i.e. blocking probability, relative to new calls because forced terminations of ongoing calls due to hand-off call blocking are generally more objectionable then new call blocking from the subscriber's perspective. A hybrid scheme has been proposed for handover in ATM-based PCN, which combines queuing and reservation schemes. In the scheme, FIFO and Measurement Based Priority Scheme (MBPS) queuing discipline [Tekinay & Jabbari, 1992] and the Reserved Channel Scheme (RCS) [Kim et al., 1999] are used. This scheme gives handovers higher priority than queuing or reservation schemes. When reservation is applied on both radio and backbone channels, it leads to significant improvement in QoS. After applying proposed scheme there is a remarkable reduction in Forced Termination Probability (FTP) at the cost of tolerable Call Blocking Probability (CBP).","PeriodicalId":185917,"journal":{"name":"Int. J. Wirel. Opt. Commun.","volume":"6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130126153","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Topology Control Algorithms for Wireless Sensor Networks: an Overview","authors":"N. Ababneh, S. Selvadurai","doi":"10.1142/S0219799506000375","DOIUrl":"https://doi.org/10.1142/S0219799506000375","url":null,"abstract":"The main goal of a topology control scheme in wireless sensor networks is to reduce node power consumption in order to extend network lifetime. In this paper we present an overview of a range of topology control algorithms proposed in literature for wireless sensor networks. The topology control schemes in most of the existing works can be categorized into two classes: Either multi-state or power-control. We believe that most energy savings might come from turning off redundant nodes rather than by minimizing node transmit power. However, both classes of schemes could be combined for further energy savings. Each algorithm is described in depth and compared against each other to capture their uniqueness. The most important design issues of topology control are also highlighted.","PeriodicalId":185917,"journal":{"name":"Int. J. Wirel. Opt. Commun.","volume":"23 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121574868","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Topology Control in Ad Hoc Networks: a MAC Layer Solution","authors":"F. Borgonovo, L. Campelli, M. Cesana","doi":"10.1142/S0219799506000405","DOIUrl":"https://doi.org/10.1142/S0219799506000405","url":null,"abstract":"In ad-hoc networks the need for a distributed topology control algorithm is being widely recognized. In this paper we propose TC-ADHOC MAC, a medium access algorithm with topology control capabilities. The proposed algorithm aims at maintaining the minimum number of bidirectional neighbors of any wireless terminal very close to a certain connectivity threshold. The correctness of the algorithm is evaluated through detailed simulation and several test on the impact of different algorithm parameters are carried out in static network scenarios. Furthermore, the ability of TC-ADHOC MAC of reusing the radio resources is assessed by a detailed simulation in a dynamic traffic environment. Our results show that the topology control solution integrated at the MAC layer helps increasing the channel reuse and, consequently, the network efficiency.","PeriodicalId":185917,"journal":{"name":"Int. J. Wirel. Opt. Commun.","volume":"34 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124981704","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Node Fragility versus Link Fragility for Route Selection in Mobile Ad Hoc Networks","authors":"I. S. Ismail","doi":"10.1142/S0219799506000399","DOIUrl":"https://doi.org/10.1142/S0219799506000399","url":null,"abstract":"A mobile ad-hoc network is a dynamically changing network of mobile devices that communicate without the support of a fixed structure. There is a direct communication among the neighboring devices, but non-neighboring devices requires a robust and intelligent routing strategy to ensure reliable and efficient communication. The performance of routing protocols depends on the quality of the routes chosen in terms of route longevity. A protocol that discovers better routes also features a reduced rate of route failures and lesser route discovery traffic. Thus an important aspect of the decision process is to compare and pick the more stable route. A Route Fragility Coefficient (RFC) metric was used to estimate routes' stability. In this paper, the link fragility metric is used to create a new metric called Node Fragility Coefficient (NFC) that is also used to estimate routes' stability. Comparing routing protocols using RFC and NFC metrics to select the more stable routes, simulation results prove that using NFC is much better, it leads to better throughput, average packet's delay, average number of hops/ packet, average consumed power/ packet, percentage number of route changes and percentage number of undelivered packets.","PeriodicalId":185917,"journal":{"name":"Int. J. Wirel. Opt. Commun.","volume":"37 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114451721","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}