A New Enhanced Fast Handover Algorithm in Hierarchical Mobile IPv6 Network

1　Introduction　MobileIPv6requirestheMobileNode (MN)toregisterwiththeHomeAgent (HA)andtheCorre spondentNode (CN)whenitchangesitspointofattachmentintheInternet[1～ 3] .Therefore ,thiscauseMobileIPv6toincurlongdelayintheregis tration process,andaddsignalingtraffictothebackbonenetworkespeciallywhentheHAandCNarefarawayfromtheMN .Inordertominimizethisdelay ,andthesignalingoverhead presentinMobileIPv6,literatures[4～7] proposeHierarchicalMobileIPv6(HMIPv6)architectureandafasthan dover…     

Registration Cost Performance Analysis of a Hierarchical Mobile Internet Protocol Network

1　Introduction　MobileIP[1～3] isanetworklayersolutiontonodemobilityintheInternet.ItmeansthatMobileIPaccomplishesitstaskbysettinguptheroutingtablesinappropriatenodes,suchthatIPpacketscanbesenttomobilenodesnotconnectedtotheirhomenetworklinks.　AlthoughMobileIPissuitedformacro mobility ,itfailstosupportmicro mobilityefficiently[4～5] .MobileIPrequirestheMobileNode (MN)toregis terwiththeHomeAgent (HA)andtheCorrespon dentNode (CN)whenitchangesitspointofattach mentintheInternet.Therefor…     

Mobile Phone Antenna Performance and Power Absorption in Terms of Handset Size and Distance from User’s Head

In this work numerical simulation and measurements of three-dimensional radiation patterns of a mobile handset model in the presence of a human head phantom were performed at 1800 MHz. Based on theoretical and experimental results, the influence of the human head on the radiation efficiency of the handset has been investigated as a function of the handset size and the distance between the head and the handset during its operation. Furthermore, the relative amount of the electromagnetic power absorbed in the head has been obtained. It was found that significant reduction of the absorbed power (about 50%) with proportional increment of the handset radiation efficiency could be achieved by moving the phone for 1 cm only away from the head. Agreement between theoretical and experimental results was found to be very good.Theodore Zervos was born in Athens, Greece, on October 5, 1978. He received the diploma in Electrical & Computer Engineering from the University of Patras, Patras, Greece, in 2001. He is currently a Postgraduate Student at the Laboratory of Electromagnetics, Department of Electrical & Computer Engineering, University of Patras. He is also a doctoral scholar at the Mobile Communications Laboratory of the Institute of Informatics and Telecommunications of NCSR Demokritos, Athens. His research interests include electromagnetic modelling, EM radiation measurements and interaction between the human body and mobile handsets antenna. Dipl. T. Zervos is a Member of the Technical Chamber of Greece. In June 2002, his thesis received the 2nd Award of Excellence in Telecommunications from Ericsson.Antonis Alexandridis (1962) is senior researcher in the Institute of informatics and Telecommunications (IIT) of Greek National Research Centre (NCSR) Demokritos. He received the diploma in Electrical Engineering from Technical University ofPatras, Greece (1985), and the Ph.D. degree from the same University (1992). From 1993 he is working in the Mobile Communications Lab of NCSR. Since 1999 he is responsible for the operation of the RF Anechoic Chamber of the IIT. His current interests include mobile communications, propagation models, spread spectrum systems and CDMA techniques, EMC measurements, human exposure to EM fields, interaction between human body and mobile terminals antennas and smart antennas.Vladimir V. Petrovic was born in 1965 in Belgrade, Serbia. He received the B.Sc., M.Sc., and D.Sc., degrees from the University of Belgrade, Serbia and Montenegro in 1989, 1993, and 1996, respectively. He joined the Faculty of Electrical Engineering, University of Belgrade in 1990, where at present he is an Assistant Professor in Electromagnetics and Fundamentals of Electrical Engineering. He is a co-author of a chapter in a monograph, a software package AWAS 2.0 (Artech House – Boston, London, 2002) and several journal and conference articles. His research interests are in numerical electromagnetics, especially in radiation and propagation problems in layered media.Kostas Dangakis was born in Kavala, Greece, in 1950. He received his Diploma in Electrical Engineering from NTUA (Athens, 1973) and his Ph.D. on Digital Modulation/Data Transmission from Techn. Univ. of Patras, Dept. of Electrical Engineering (1984). Since 1977, he has worked at the Inst. of Inform. & Telecom. (IIT) of NCSR Demokritos, in projects related to voice/data/video signal encryption, synchronisation techniques in TDM systems, digital modulation techniques/data transmission, Spread Spectrum/CDMA techniques, mobile communications, conformance testing (DECT, ERMES), radio propagation, channel characterization and antennas. He is research director at IIT and has been project leader of several R & D projects.Branko M. Kolundzija Antonije R. Djordjevic was born in Belgrade, Yugoslavia, on April 28, 1952. He received the B.Sc., M.Sc., and D.Sc. degrees from the Faculty of Electrical Engineering, University of Belgrade, in 1975, 1977, and 1979, respectively. In 1975, he joined the School of Electrical Engineering, University of Belgrade, as a Teaching Assistant. He was promoted to an Assistant Professor, Associate Professor, and Professor, in 1982, 1988, and 1992, respectively. In 1983, he was a Visiting Associate Professor at Rochester Institute of Technology, Rochester, NY. Since 1992, he has also been an Adjunct Scholar with Syracuse University, Syracuse, NY. In 1997, he was elected a Corresponding Member of the Serbian Academy of Sciences and Arts. His main area of interest is numerical electromagnetics, in particular applied to fast digital signal interconnects, wire and surface antennas, microwave passive circuits, and electromagnetic-compatibility problems.C. Soras received both his diploma and Ph.D. in electrical engineering from the University of Patras, Patras, Greece, in 1981 and 1989 respectively. He was a Lecturer in the Laboratory of Electromagnetics of the Electrical and Computer Engineering department of the University of Patras in Greece from 1991 to 2001, where currently serves as an Assistant Professor. He is teaching the basic electromagnetic courses and at the senior undergraduate / graduate level computational electromagnetics. His current research interests focus on computational electromagnetics, multiple element antennas for diversity and MIMO terminal devices and indoor radio wave propagation. Prof. Soras is a member of IEEE, Applied Computational Electromagnetics Society and the Technical Chamber of Greece.     

Optimization of MQAM Modulation Schemes in Mobile Communications（Ⅱ）—Analysis of MQAM BER Performance in Rayleigh Channel

The transmission error code performance of square MQAM and star MQAM modulation schemes for the AGWN Rayleigh fading channel is analyzed.The corresponding BERformulas and computer aided numeric results are given.Therefore it provides a theoretical basis for choosing MQAM modulation schemes in mobile communications.     

Circuit Topology Analysis of CMOS LNA in Mobile Communication Systems

1　Introduction　Now ,mostoftheLNAinRFreceiversarede signedwithGaAsorbipolartechnologies,whichhavealargepowerdissipationandunfavorableper formanceofintegration .CMOStechnologiestakeincreasinglyadvantagesoftechnologyadvances,whichhaveverylow powerconsumptionandmakepossibletheintegrationofcompletecommunicationsystems[1 ] .Forexample ,mobilecommunicationsystemreceiversemployextensivedigitalsignalpro cessingtoperformacquisition ,tracking ,anddecod ingfunctions.TheuseofCMOStechnologiesforimpl…     

Performance Analysis of MC-CDMA in the Presence of Carriers Phase Errors

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How much do we gain by introducing route optimization in Proxy Mobile IPv6 networks?

Proxy Mobile IPv6 has been developed from the concept of network-based mobility support protocol in the Internet Engineering Task Force. The recently published specification of Proxy Mobile IPv6 only focuses on the mobility support without a mobile host’s participation in the mobility signaling. Then, route optimization issues are left in the basket for further works. In this paper, we explore the existing route optimization proposals that are analyzed and matched against a list of functional and operational angles. Then, the chosen two route optimization proposals are evaluated in terms of signaling cost, packet delivery cost, total cost, and service blocking probability. Through the provided analysis results, we demonstrate that route optimization solves the ineffective routing path problem when the mobile host communicates with its corresponding host and argue that the scalability of Proxy Mobile IPv6 architecture is also improved due to the distributed routing path. In addition, the cost model developed in this paper would be a reference model in order to facilitate decision making for further route optimization design.     

Optimization of MQAM Modulation Schemes in Mobile Communications(Ⅰ)——Analysis of MQAM BER Performance in AGWN Channel Based on Signal Space

Based on signal space concepts, a transmission error code performance for MPSK, square MQAM and star MQAM modulation schemes on the AGWN channel is analyzed. The corresponding BER formulas and computer aided numeric results are also given. Therefore it provides a theoretical basis for choosing MQAM modulation schemes in mobile communications.     

The Analysis of Frequency Reuse Irregular Patterns in Mobile Telephone Network

Some frequency reuse irregular patterns in radionetwork design are proposed,the characteristic and applica-tion measures of these patterns are analyzed.Then this paperaccounts that frequency reuse irregular patterns is a usefulway to impove spectrum efficiency and it is significative forartificial intelligence to be applied in this field.     

Optimization of MQAM Modulation Schemes in Mobile Communications（I）—Analysis of MQAM BER Performance in AGWN Channel Based on Signal Space

Based on signal space concepts, a transmission error code performance for MPSK, square MQAM and star MQAM modulation schemes on the AGWN channel is analyzed.The corresponding BER formulas and computer aided numeric results are also given.Therefore it provides a theoretical basis for choosing MQAM modulation schemes in mobile communications.     

Performance Analysis of Slotted Multichannel ALOHA Systems with Capture in Microcellular Environments

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Calculation and Analysis of Destination Buffer for Multimedia Service in Mobile Ad Hoc Network

Jitter is one of the most important issues for multimedia real time services in future mobile ad hoc networks（MANET）. A thorough theoretical analysis of the destination buffer for smoothing the jitter of the real time service in MANET is given. The theoretical results are applied in moderate populated ad hoc networks in our simulation, the simulation results show that by predicting and adjusting destination buffer in our way, Jitter will be alleviated in large part and this will contribute much to the quality of service （QOS） in MANET.     

Performance Analysis of a DS-CDMA Cellular System with Effects of Soft Handoff in Log-Normal Shadowing Channels

Next generation wireless communication is based on a global system of fixed and wireless mobile services thatare transportable across different network back-bones,network service providers and network geographical boundaries.This paper presents an approach to investigate the effects of soft handover and perfect power control on the forward link ina DS-CDMA cellular system.Especially,the relationships between the size ofhandover zone and the capacity gain are e-valuated under the log-normal shadow channel.Then the optimization of maximum forward capacity is very necessary tobe done with the maximum size of soft handover zone to the various system characteristics.     

Performance Analysis of Combined mMCSK–mMFSK Modulation in AWGN and Rayleigh Fading Channel

As there are many use cases considered for robotics communications, the data rate variation may be very large. Some sensor applications may require very low data rate, telemetry data may require low-to-medium data rates and e.g. video application will require high data rates. On the other hand, robots may have to operate in very difficult radio propagation environments such as nuclear power plants or industrial facilities. To combat difficult propagation characteristics, an often used and well known mechanism is to use spread spectrum signal structures. Thus in this paper a novel modulation method is considered which offers the inherent signal structure and processing opportunities of spread spectrum signal and at the same time offers an easy mechanism to adapt the data rate from low to high depending on the requirement at hand thus addressing two important communication requirements for robotics. The introduction of $m$ MFSK generated the idea of applying the given approach to other modulation methods. To further enlarge the modulation alphabet sizes (with the price of larger spectrum usage) it was realized that combining the $m$ MFSK and $m$ MCSK would be an interesting choice. The $m$ MCSK– $m$ MFSK modulation is hence considered. A method to analyze this two-component modulation is developed and the performance analyses give results for $m$ MCSK– $m$ MFSK modulation in AWGN and flat Rayleigh fading channels for both coherent and non-coherent receivers. The performance was also assessed with orthogonal and non-orthogonal code constructs for coherent receiver.     

How Does Multiple-Packet Reception Capability Scale the Performance of Wireless Local Area Networks?

Due to its simplicity and cost efficiency, wireless local area network (WLAN) enjoys unique advantages in providing high-speed and low-cost wireless services in hot spots and indoor environments. Traditional WLAN medium-access-control (MAC) protocols assume that only one station can transmit at a time: simultaneous transmissions of more than one station cause the destruction of all packets involved. By exploiting recent advances in PHY-layer multiuser detection (MUD) techniques, it is possible for a receiver to receive multiple packets simultaneously. This paper argues that such multipacket reception (MPR) capability can greatly enhance the capacity of future WLANs. In addition, the paper provides the MAC-layer and PHY-layer designs needed to achieve the improved capacity. First, to demonstrate MPR as a powerful capacity-enhancement technique, we prove a "superlinearity” result, which states that the system throughput per unit cost increases as the MPR capability increases. Second, we show that the commonly deployed binary exponential backoff (BEB) algorithm in today's WLAN MAC may not be optimal in an MPR system, and the optimal backoff factor increases with the MPR capability, the number of packets that can be received simultaneously. Third, based on the above insights, we design a joint MAC-PHY layer protocol for an IEEE 802.11-like WLAN that incorporates advanced PHY-layer signal processing techniques to implement MPR.     

Tone mapping based HDR compression: Does it affect visual experience?

High Dynamic Range (HDR) content is visually more appealing since it can represent the real luminance of the scene. However, on the downside, this means that a large amount of data needs to be handled both during storage and processing. The other problem is that HDR content cannot be displayed on the conventional display devices due to their limited dynamic range. To overcome these two problems, dynamic range compression (or range reduction) is often used and this is accomplished by tone mapping operators (TMOs). As result of tone mapping, the HDR content is not only fit to be displayed on a regular display device but also compressed. However from an artistic intention point of view, TMOs are not necessarily transparent and might induce different viewing behavior. It is generally accepted that TMOs reduce visual quality and there have been a number of studies reported in literature which examine the impact of tone mapping from the view point of perceptual quality. In contrast to this, it is largely unclear if tone mapping will induce changes in visual attention (VA) as well and whether these are significant enough to be accounted for in HDR content processing. To our knowledge, no systematic study exists which sheds light on this issue. Given that VA is a crucial visual perception mechanism which affects the way we perceive visual signals, it is important to study the effect of tone mapping on VA deployment. Towards this goal, this paper investigates and quantifies how TMOs modify VA. Comprehensive subjective tests in the form of eye-tracking experiments have been conducted on several HDR content and using a large number of TMOs. Further non-parametric statistical analysis has been carried out to ascertain the statistical significance of the results obtained. Our studies suggest that TMOs can indeed modify human attention and fixation behavior. Based on this we believe that VA needs consideration for evaluating the overall perceptual impact of TMOs on HDR content. As mentioned, since the existing studies so far have only considered the quality or esthetic appeal angle, this study brings in a new perspective regarding the importance of VA in HDR content processing for visualization on LDR displays.     

The diffusivity of the vacancy in silicon: Is it fast or slow?

Vacancies in silicon are known to be highly mobile both at high temperatures (just below the melting point) and at cryogenic temperatures. Contrary to this, however, vacancy diffusivity near 800 °C — as deduced from the radiation-enhanced self-diffusion coefficient D_sd — was reported to be surprisingly low. An apparent explanation of this contradiction is that the defect concentrations (and accordingly D_sd) are reduced by an impurity-mediated recombination of vacancies and self-interstitials. This effect however is shown to be insufficient to account for such a low D_sd. A suggested solution to the puzzle is that self-interstitials (and vacancies as well) exist in two structural forms, a localized one and an extended one, of strongly differing diffusivities. A low diffusivity manifested in radiation-enhanced self-diffusion is likely to correspond to a low apparent diffusivity of self-interstitials (averaged over the two forms) rather than that of vacancies. The fast and slow forms of vacancies are concluded to be both of a high diffusivity at elevated temperatures while it is most likely that one of them (the extended one) becomes practically immobile at low temperatures.     

Adoption of ERP systems: Does information transparency matter?

Research on the adoption of Enterprise Resource Planning (ERP) systems has drawn much attention in the information systems (IS) research. This study extends previous research on ERP adoption by examining the direct and indirect effects of perceived information transparency that result from the adoption of ERP systems. Based on the extensive review of literature grounded in the technology acceptance model and theory of reasoned action, a research model is proposed. The proposed model is validated by a survey of 106 ERP users. The results of this survey confirm that perceived information transparency of the ERP system has significant direct effects on perceived usefulness, ease of use, and indirect effects on attitude and adoption. Moreover, the perceived usefulness fully mediates the relationship between information transparency and the attitude toward using the ERP system. This study expands the existing body of knowledge on the adoption of ERP systems, and benefits ERP providers and vendors when formulating their business models.     

Quality improvement: what is in it for the patient?

The improvement of health care service has a great effect on patient satisfaction. During the service delivery, the health care organization attempts to answer the reasonable expectations of patients. The expectations relate to many service dimensions, among them the phone system, appointment availability and waiting times. The research questions of this study are: can the implementation of quality initiatives improve patient satisfaction with the phone system, appointment availability and waiting times and do patients from diverse cultural backgrounds exhibit different levels of satisfaction? The study was undertaken in a public clinic, with a culturally diverse clientele, including 194 patients. The authors use a combination of the longitudinal and cross-sectional research design to test the propositional model. The findings show that the implementation of the quality initiative significantly improved patient satisfaction with the appointment availability and waiting time. On the other hand, the implementation of the quality initiative did not improve patient satisfaction with the phone system. Some culturally diverse patients exhibited different levels of expectations of the care provider and quality in terms of patient satisfaction with the appointment availability