Please wait a minute...
[an error occurred while processing this directive]

当期目录

    2011年 第9卷 第2期    刊出日期:2011-06-25
    The whole issue of ZTE Communications June 2011, Vol. 9 No. 2
    2011, 9(2):  0. 
    摘要 ( )   PDF (2802KB) ( )  
    相关文章 | 多维度评价
    Guest Editorial: Microwave/RF Technologies for Future Wireless Communications
    Ke-Li Wu and Keqiang Zhu
    2011, 9(2):  1-1. 
    摘要 ( )   PDF (192KB) ( )  
    相关文章 | 多维度评价
    Compared with 2G, the most prominent features of 3G and future wireless communication systems are a higher transmission rate and support for multimedia services. A higher transmission rate means that signal bandwidth is large, use of frequency spectrum is more efficient, and radio frequency equipment is greener. Demand for richer multimedia services is creating greater challenges for system developers and has led not only to the publication of tens of thousands of documents but also to tremendous new technology developments in the Long-Term Evolution (LTE) of 3GPP’s Universal Mobile Telephone System (UMTS).

    International deployment of UMTS is progressing steadily, and more than 180 mobile network operators throughout Europe, North America, and Asia are providing 3G services. High Speed Downlink Packet Access (HSDPA) and High Speed Uplink Packet Access (HSUPA) in UMTS can improve the transmission data rate and spectrum efficiency. This reduces transmission cost per bit. The trend towards increased data traffic and high-capacity content requires that base station equipment use new and existing frequency bands flexibly. This trend also requires that base stations have simplified but flexible network architecture with open interfaces and to consume less power. These requirements must be achieved by developing more efficient power amplifiers and broadband antennas as well as more compact high performance RF filters with less insertion loss.

    In this special issue on microwave/RF technologies for future wireless communications, we invited five experts to contribute articles. Each of these articles shows a different aspect of the challenges and advanced technologies involved in microwave/RF for future wireless communications—from system architecture requirements, technologies in broadband power amplifiers, advanced RF dielectric resonator filters, and broadband antenna technologies to the state-of-the-art synthesis theory of sophisticated microwave/RF filters. We understand that these topics are far from enough to provide a complete picture of the industry, and some of the topics in this special issue are, indeed, classic. Nevertheless, we have obtained contributions from five experts, including the most experienced system architects in the industry, a senior RF engineer in power amplifiers, an industry leader who has been working on dielectric filters for more than two decades, a top tier scholar in broadband base station antennas, and the most eminent researcher in the microwave filter industry. Such combined efforts have made this issue very special.

    We are very grateful to all the authors, reviewers, and the editorial board who have spent their valuable time on this special issue. We hope you will find the articles useful to your professional work and enjoyable to read.
    RF Technologies and Challenges for Future MBR Systems in Cellular Base Stations
    Hongyin Liao, Baiqing Zong, Jianli Wang, Keqiang Zhu, and Changjiang Cao
    2011, 9(2):  2-7. 
    摘要 ( )   PDF (330KB) ( )  
    相关文章 | 多维度评价
    This paper describes the advances and features of future cellular base stations. Software defined radio (SDR) evolves to cognitive radio (CR), which is smart and has wideband, and multiband radio (MBR) with reconfigurable wideband can be regarded as the basis of CR and an advanced level of SDR. Based on the SDR platform, several radio frequency (RF) solutions for implementing MBR systems are proposed, and some challenges to MBR implementation are discussed.
    Broadband Power Amplifiers for Unified Base Stations
    Pengcheng Jia
    2011, 9(2):  8-11. 
    摘要 ( )   PDF (369KB) ( )  
    相关文章 | 多维度评价
    A broadband power amplifier is required to cover the full range of cellular frequency band—from 700 MHz to 2600 MHz—in a base station that supports multiple frequency bands simultaneously. Conventional laterally diffused metal oxide semiconductor (LDMOS) transistors support narrow band applications up to 3 GHz. However, they cannot operate beyond 1 GHz in broadband applications. GaN transistors have much higher power density and operational frequency compared with LDMOS. Therefore, they are ideal for broadband amplifiers that support multiple bands. Theories for designing broadband amplifiers are introduced in this article, and a 500-2500 MHz 60 W GaN amplifier is discussed.
    Single Mode DR Filters for Wireless Base Stations
    Ji-Fuh Liang, Guo-Chun Liang, Marco Song, George He, and Tony An
    2011, 9(2):  12-19. 
    摘要 ( )   PDF (634KB) ( )  
    相关文章 | 多维度评价
    This paper presents state-of-the-art high Q single-mode dielectric resonator (DR) cavity filters for PCS wireless base stations. DR cavity filters shrink the cavity size significantly more than waveguide cavity filters and offer about twice higher Q than coaxial resonators. Thus, they have important applications in wireless base stations operating below 2.5 GHz. Dual-mode and triple-mode DR cavity filters have existed for a while; however, single-mode DR cavity filters are predominant because they are cheaper to manufacture. This paper summarizes the main characteristics of TE01 mode DR cavities, including mode chart and field distribution, and compares cavity Q with waveguide and combline (coaxial) cavities. Dielectric combline and TM010 mode DR cavities are analyzed and compared to TE01 mode DR cavities. General filter design techniques are discussed, and several design examples are given to show how filter technology has developed.
    Design of a Magneto-Electric Dipole Element for Mobile Communication Base Station Antennas
    Hang Wong and Kwai Man Luk
    2011, 9(2):  20-26. 
    摘要 ( )   PDF (758KB) ( )  
    相关文章 | 多维度评价
    The magneto-electric dipole antenna is a kind of complementary antenna composed of a planar electric dipole and a shorted patch antenna. It has excellent electrical characteristics including wide impedance bandwidth, low cross-polarization, low back lobe radiation, nearly identical E-plane and H-plane patterns, stable radiation pattern, and steady antenna gain over the operating frequency range. In this paper, the basic characteristics of a linearly polarized magneto-electric dipole antenna are reviewed, and a dual-polarized antenna element based on the magneto-electric dipole is presented. The design of a conical beam wideband antenna with horizontal polarization is also described. These antennas have practical applications in modern 2G, 3G, LTE, WiFi, and WiMax wireless communication systems.
    Advanced Synthesis Techniques for Microwave Filters
    Richard J Cameron
    2011, 9(2):  27-35. 
    摘要 ( )   PDF (453KB) ( )  
    相关文章 | 多维度评价
    With the advent of the‘digital revolution’that has made possible services such as the world wide web, satellite broadcasting and mobile and trunk telephony, the finite RF spectrum allocated for terrestrial and satellite telecommunication systems is becoming increasingly crowded. This has impacted significantly upon the performance required from the microwave equipment that comprises these systems. In the case of microwave filters, greater in-band linearity to avoid signal distortion and out-of-band isolation to suppress interference are routinely specified, which can only be satisfied by advanced filtering characteristics. This article presents the coupling matrix approach to the synthesis of prototype filter networks, enabling the realization of the hardware embodying the enhanced performance needed by today’s high capacity systems.
    Privacy-Preserving Protocol for Data Stored in the Cloud
    Hongyi Su, Geng Yang, and Dawei Li
    2011, 9(2):  36-38. 
    摘要 ( )   PDF (314KB) ( )  
    相关文章 | 多维度评价
    Data storage is an important application of cloud computing. With a cloud computing platform, the burden of local data storage can be reduced. However, services and applications in a cloud may come from different providers, and creating an efficient protocol to protect privacy is critical. We propose a verification protocol for cloud database entries that protects against untrusted service providers. Based on identity-based encryption (IBE) for cloud storage, this protocol guards against breaches of privacy in cloud storage. It prevents service providers from easily constructing cloud storage and forging the signature of data owners by secret sharing. Simulation results confirm the availability and efficiency of the proposed protocol.
    A Mobility Management Solution Based on ID/Locator Separation
    Yuhong Li, Yunjing Hou, and Shiduan Cheng
    2011, 9(2):  39-43. 
    摘要 ( )   PDF (349KB) ( )  
    相关文章 | 多维度评价
    Current mobility management solutions based on ID/Locator separation are not easily deployed and cannot solve routing scalability and mobility problems. This paper proposes a novel network architecture based on ID/Locator separation and suggests a new mobility management solution. This solution solves the problem of scalability in the network and also provides better support for mobility. It can be easily deployed because no modification of the mobile host’s protocol stack is required. The identifier contains some routing information; so the solution provides intrinsic interworking with traditional mobile hosts. Because the mapping systems are distributed to the edge networks, robustness of the whole system is enhanced and handover delay is decreased.
    Self-Adaptive QoS Control in Cognitive Networks That Is Based on Service Awareness
    Chengjie Gu, Shunyi Zhang, and Yanfei Sun
    2011, 9(2):  44-48. 
    摘要 ( )   PDF (327KB) ( )  
    相关文章 | 多维度评价
    This paper analyzes a self-adaptive Quality of Service (QoS) control architecture for cognitive networks (CNs) that is based on intelligent service awareness. In this architecture, packets can be identified and classified using an intelligent service-aware classification model. Drawing on Control Theory, network traffic can be controlled with a self-adaptive QoS control mechanism that has side-road collaboration. In this architecture, perception, analysis, correlation, feedback, decision making, allocation, and implementation QoS mechanisms are created automatically. These mechanisms can adjust resource allocation, adapt to a changeable network environment, optimize end-to-end performance of the network, and ensure QoS.
    A P2PSIP System with Intelligent Routing Function on the Media Plane
    Yongsheng Hu, Zhenwu Hao, Jun Wang, and Naibao Zhou
    2011, 9(2):  49-52. 
    摘要 ( )   PDF (380KB) ( )  
    相关文章 | 多维度评价
    Decentralized peer-to-peer session initiation protocol (P2PSIP) provides the same services as legacy SIPs such as IMS. However, in relatively open network, the requirement for route efficiency in a complex environment brings about undefined problems. To deploy a controllable P2PSIP network, perfect mechanisms have to be appended, especially in QoS, security, and management. Several proposals for QoS, network address translation (NAT), and interworking have been put forward. In this paper, we propose an integrated architecture for a P2PSIP system as well as a proactive intelligent routing scheme on the media plane used in system. Implementation and simulation show that our solution is suitable for operation and management.
    Architecture and Key Technology of Distributed Intelligent Open Systems
    Xiaoyu Tong , Yunyong Zhang , and Bingyi Fang
    2011, 9(2):  53-57. 
    摘要 ( )   PDF (416KB) ( )  
    相关文章 | 多维度评价
    High-speed large-bandwidth networks and growth in rich internet applications has brought unprecedented pressure to bear on telecom operators. Consequently, operators need to play to the advantages of their networks, make good use of their large customer bases, and expand their business resources in service, platform, and interface. Network and customer resources should be integrated in order to create new business ecosystems. This paper describes new threats and challenges facing telecom operators and analyzes how leading operators are handling transformation in terms of operations and business model. A new concept called distributed intelligent open system (DIOS)—a public computing communication network—is proposed. The architecture and key technologies of DIOS is discussed in detail.
    The Internet of Things and Ubiquitous Intelligence (2)
    Dongliang Xie and Yu Wang
    2011, 9(2):  58-61. 
    摘要 ( )   PDF (537KB) ( )  
    相关文章 | 多维度评价