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The great success of the i‐mode service shows that data communication services are becoming accepted in the mobile communication world. Multimedia mobile communication services will be provided by 3rd generation IMT‐2000 systems next year in Japan. Thus, the time has come to begin the research and development for 4th generation (4G) mobile communication systems. There exist many difficult issues for 4G systems, such as frequency resources, additional investment, higher speed wireless transmission technology and so on. Furthermore, a new concept must be discussed for 4G before solving these issues. This paper briefly presents current conditions of cellular systems and the development of IMT‐2000 in Japan. The concept and problems of the 4G system are then described along with new technologies that will be useful in solving technical problems. Copyright © 2001 John Wiley & Sons, Ltd. 相似文献
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Employees in today’s enterprises are requesting their employers to allow them to work in a flexible manner. Work is no longer
a place to go to but an activity to be undertaken. With developments in technology, the activity can be undertaken whenever
and wherever it is convenient for the employees. Increasing demands by employees to be able to work in this way creates a
tension within the enterprise as CIOs and finance officers strive to manage the costs and the infrastructure required to support
this way of working. Over time, this situation will change as technology allows users to roam securely and seamlessly between
networks accessing the required applications and information from a single suitably enabled device. This will tend to reduce
the underlying costs as the best connection can be used. Service management will remain a challenge but become a better understood
problem as the ’stove-pipe’ nature of current solutions is removed. For this change to be brought about, some enabling technologies
have to be put in place.
This paper considers issues surrounding next generation mobile solutions and shows how converged services can be used to deliver
the vision of being able to work from any place, at any time. Consideration is given to how roaming from fixed to wireless
networks can be achieved by reusing already established authentication principles that are now deployed in wide area wireless
networks. In order to do this, open methods of managing user identity need to be devised and implemented and approaches to
this are also discussed. The paper concludes with a consideration of some of the research challenges that remain to be solved.
HP 相似文献
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Tobias Buehler 《电子产品世界》2005,(1):113-115
10多年前,当第一代蜂窝电话出现时,采用了许多分立功率器件.第一代手机显得很笨重,高功耗使得待机时间和通话时间都很短.为了响应客户对外形更小,性能更高的无线电子设备不断增长的需求,工程师发展了许多先进的设计技术.这些技术既可缩小印刷电路板(PCB)尺寸,又可以提供更快更高效的性能. 相似文献
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《Communications Magazine, IEEE》2006,44(9):62-71
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Europe's third-generation mobile communication system will transform the capabilities of cellular networks. The authors describe some of the implications for users, network operators and would-be licence holders of UMTS (Universal Mobile Telephone System) 相似文献
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This paper outlines the path from developing broadband ISDN/ATM systems towards the European vision of the next generation mobile system — Universal Mobile Telecommunications System (UMTS).The capabilities of UMTS in terms of services and features compared to the second generation mobile system GSM, and the network technologies behind N-ISDN and B-ISDN, are discussed with proposals for technical developments to satisfy the UMTS requirements. The UMTS radio interface aspects are described and considerations on the network requirements to support these radio aspects are discussed.The requirements within the network for control, switching and transport to support the mobility, service and interconnecting network aspects of UMTS are outlined in conjunction with the technical solutions currently under discussion and some latest thoughts on a potential high-level architecture 相似文献
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《Latin America Transactions, IEEE (Revista IEEE America Latina)》2008,6(2):194-200
Next generation of mobile communications will be based on a heterogeneous infrastructure comprising different wireless access systems in a complementary manner. This paper proposes a network selection algorithm based on user activity, user preferences, service requirements, and networks conditions which provides users a prospect of being always best connected within an environment of heterogeneous mobile networks. This is achieved by a learning process which allows user to select an access network based in previous connections and a cost function that helps the user to select the best network that adapts to the needs. 相似文献
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Second-generation mobile radio systems have been deployed successfully worldwide. These systems have evolved to higher data rates and packet transmission. Third-generation mobile radio systems are currently being standardized worldwide to be initially deployed in 2001 and 2002 in different regions of the world. New advanced multimedia services are under development, and first services are already being offered in second-generation systems, which will provide new business opportunities. Already today discussion is starting on the development of systems beyond third-generation mobile radio systems due to the long timeframe for system specification and international standardization. However, today there is no clear vision available on such systems. This discussion takes into account the new deregulated and liberalized communication environment. This article presents a concept for a system beyond third-generation mobile radio systems, which comprises a combination of several optimized access systems in a common IP-based medium access and core network platform. These different access systems will interwork through horizontal and vertical handover, service negotiation, and global roaming. The different access systems are allocated to different mutually complementing cell layers in the sense of hierarchical cells with respect to cell size, coverage, and mobility to provide globally optimized seamless services to users. This vision requires extensive international research and standardization activities to solve many technical challenges. Key issues are the global interworking of different access systems on a common platform, advanced antenna concepts, and the implementation of multimode and multiband terminals and base stations through software-defined radio concepts. 相似文献
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亚太地区 1999年增加了5000万移动电话用户,虽然自1997年以来该地区经历过金融风暴等经济困难,但是总用户基数还是比前两年增加了2倍多。 Baskerville最近编制的《全球移动通信市场预测(第二版)》认为,整个亚太地区 20O0年的移动电话普及率可以提高到6%左右。其预测还显示:到2003年底,移动电话普及率将达到10%;而到2008年底,移动电话用户将激增到5亿,普及率接近12%。 在亚洲使用的2G技术中,GSM的用户数占有很大的优势。大部分模拟网络将逐渐被淘汰,预测认为,到2002年,… 相似文献
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Seamless inter-technology mobility is one of the fundamental requirements of next generation mobile networks. For seamless mobility, handover delay and packet loss should be minimized. However, existing solutions suffer from a number of shortcomings in satisfying these requirements: first, handover preparation schemes fail to minimize the handover delay as much as possible. Second, minimizing packet loss which is usually using soft handover (SHO) schemes are excessively wasteful of scarce resources. In this paper, we propose the uninterrupted proactive connection transfer for IMS mobility enhancement (UPTIME) mobility framework which achieves seamless mobility while minimizing excessive power and radio resource consumption. UPTIME incorporates two mechanisms; a proactive handover preparation method and an optimized SHO technique for handover execution. We demonstrate the benefits of the proposed framework through both analysis and simulation. Our simulation results for typical LTE/WiMAX handovers show that the handover preparation delay can be reduced by 70 %, and good packet loss performance can be achieved whilst saving 43 % of radio resources and 48 % of battery power. 相似文献
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On designing issues of the next generation mobile network 总被引:2,自引:0,他引:2
M. Rubaiyat Kibria Abbas Jamalipour 《IEEE network》2007,21(1):6-13
Next generation mobile network (NGMN) is envisaged to support seamless mobility across disparate access technologies in a transparent manner. The success of NGMN design will depend on its ability to address key design issues, mainly architectural adaptation and modification of service continuity functions (i.e., mobility and resource management) that arise from such interoperability. The solutions presented in this article attempt to resolve these issues by considering an IP-based interworking framework that promotes evolution of individual networks and integration of new technologies 相似文献
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Luan Huang Yajian Liu Shyamalie Thilakawardana Rahim Tafazolli 《Communications Letters, IEEE》2006,10(12):822-824
This letter addresses the user assignment problem for multimedia streaming applications in heterogeneous multicast-enabled wireless networks using a network-centric strategy. The optimal problem is mathematically formulated and proven to be non-deterministic polynomial-time (NP)-hard. An efficient heuristic algorithm is then proposed to find sub-optimal solutions in practical systems. Simulation results demonstrate the improved performance of this heuristic in comparison to a conventional user-centric algorithm 相似文献
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As many geo-located Web services will be deployed in the future, mobile clients will be interested in locating a specific application server based on requirements such as proximity, service cost per location area, bandwidth, and server utilization rates. This paper presents a middleware system called GLWSA (Geo-Located Web Services Architecture) that aims to satisfy these requirements in addition to providing a thematic factorization of common location functions in order to locate mobile clients. The GLWSA supports a set of GLWSMs (Geo-Located Web Services Manager) distributed over the mobile network. It defines protocols to discover and inform a Supplier Application Server (SAS) to migrate the service execution (from a specific client) to the nearest SAS based on the client's location. This architecture is suitable to assist mobile clients to discover the geo-located Web services and to maintain the service execution closest to their location. 相似文献
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长期演进项目(LTE)是第三代移动通信合作伙伴项目(3GPP)为下一代无线移动通信最新制定的一项标准.重点研究了LTE的关键技术,并且详细分析了3GPP定位于满足ITU提出的IMT-Advanced的LTE-Advanced标准,包括它的发展历程、演进目标、技术指标以及新的关键技术. 相似文献