Dual-frequency planar antenna for handsets

Cellular telephone handsets are now being designed to have dual-mode capabilities. In particular, GSM and DCS1800 modes are used in Europe. And PCS and AMPS modes are used in the USA. A novel planar dualband internal antenna for handsets which operates in the ~0.9 and 1.8 GHz bands is proposed. The dualband antenna has almost the same size as a conventional internal antenna operating in the 0.9 GHz band. Good dual-band operation was obtained for frequency ratios in the range 1.3-2.7     

Dual-frequency planar inverted-F antenna

Cellular telephone handsets are now being designed to have dual-mode capabilities. In particular, there is a requirement for internal antennas for GSM and DCS1800 systems. This paper describes a novel planar dual-band inverted-F antenna for cellular handsets, which operates at the 0.9-GHz and 1.8-GHz bands. The dual-band antenna has almost the same size as a conventional inverted-F antenna operating at 0.9 GHz and has an isolation between bands of better than 17 dB. The bandwidths of the antenna are close to those required for the above systems. Good dual-band action is also obtained for other frequency ratios in the range of 1.3-2.4. Studies also show that the dual-band antenna can operate with one or two feeds. A finite-difference time-domain analysis has been shown to give calculated results close to those measured     

Wideband L-probe-feed patch antenna with dual-band operation forGSM/PCS base stations

A dual-band microstrip composed of two patches and two L-probes is proposed. The antenna displays wide-bandwidth characteristics and can be implemented as a dual-mode GSM/PCS base station antenna     

中国移动通信终端市场的需求与供给

根据实际数据和统计学原理对当前和未来中国移动通信终端市场的需求和供给进行了分析。分析结果表明，预期的中国移动用户的饱和时间大约是2014年，饱和时的普及率是69．7％，移动用户总数是9．1亿，届时手机的年需求量将达到4．5亿部。分析也表明，1999～2006年“黑手机”所占市场份额为29％，而且有增长的趋势。     

iGSM: VoIP service for mobile networks

This article proposes iGSM: a voice-over-IP value-added service for the mobile network. The iGSM service provides user mobility to subscribers, which allows them to use either GSM handsets or H.323 terminals (IP phones or PCs) to access telecommunications services. We describe how the iGSM registration, deregistration, and call delivery procedures can be implemented without modifying the GSM network. We study how the tromboning effect in the standard GSM system can be avoided when accessing the IP network. Then we investigate the misrouting problem caused by user mobility     

亚太地区GSM在起飞

GSM正在向纵深发展。在地域上,已经从欧洲各国延伸到亚洲大多数国家和地区;在技术上,对各个领域都制订了详尽的规范标准,并逐步形成一个“平台”;在用户发展方面,1994年第一季度已从50万增至150万户。GSM无疑将成为全世界最主要的数字移动通信系统。     

USIM卡的鉴权需求对GSM/TD-SCDMA/TD-LTE 融合网络影响

借助存量GSM/TD-SCDMA用户,保证GSM/TD-SCMDA和TD-LTE网络业务的一致性和连续性,是TDLTE网络建设的主要原则之一。本文首先理论介绍3GPP定义USIM卡在GSM/TD-SCDMA融合网络中鉴权与加密关键技术和TD-LTE的鉴权与加密原则,其次讨论USIM卡在GSM/TD-SCDMA/TD-LTE网络中互操作时的鉴权与加密需求,最后提出利用UDC HLR解决方案建设GSM/TD-SCDMA/TD-LTE融合用户数据库解决USIM卡在GSM/TD-SCDMA/TD-LTE互操作时的接入网安全问题。     

A dual-band RF front-end for WCDMA and GSM applications

An RF front-end for dual-band dual-mode operation is presented. The front-end consumes 22.5 mW from a 1.8-V supply and is designed to be used in a direct-conversion WCDMA and GSM receiver. The front-end has been fabricated in a 0.35-μm BiCMOS process and, in both modes, can use the same devices in the signal path except the LNA input transistors. The front-end has a 27-dB gain control range, which is divided between the LNA and quadrature mixers. The measured double-sideband noise figure and voltage gain are 2.3 dB, 39.5 dB, for the GSM and 4.3 dB, 33 dB for the WCDMA, respectively. The linearity parameters IIP3 and IIP2 are -19 dBm, +35 dBm for the GSM and -14.5 dBm and +34 dBm for the WCDMA, respectively     

TD-SCDMA网络分流GSM网络数据业务方案

GSM/TD-SCDMA双模终端的数据业务流量"倒流"GSM网络现象严重,使得GSM网络负荷压力加大,而TD-SCDMA网络利用率偏低.本文针对上述问题,提出了网络2G/3G互操作参数调整、网络控制的2G到3GPS小区重选以及新型双模终端的综合解决方案,实现TD-SCDMA分流GSM网络数据业务,均衡2G/3G双网协调...     

GSM900/1800双频网话务均衡与应用

为了改善小区拥塞情况,提高TCH利用率,介绍了GSM900/1800组网方式和无线传播的特点,通过对双频网话务均衡优化方法的分析,提出了对小区重选及切换参数的设置的优化方案,实现了GSM1800对话务量的吸收作用,达到了双频网话务均衡的目标。     

Reconfigurable multilayer dual-mode bandpass filter based on memristive switch

A novel memristor-based multilayer dual-mode resonator is presented, which is suitable for the design of reconfigurable multi-band filters. The memristor is used as an RF/microwave switch. A dual-band bandpass filter is realized with the proposed memristor-based dual-mode resonators. The corresponding memristor setup circuitry is optimized in order to minimize the circuitry influence on the desired filter frequency response.     

USIM卡的鉴权需求对GSM\TD-SCDAM\TD-LTE融合网络影响

借助存量GSM\TD-SCDMA用户,保证GSM\TD-SCMDA和TD-LTE网络业务的一致性和连续性,是TD-LTE网络建设的主要原则之一。本文首先理论介绍3GPP定义USIM卡在GSM\TD-SCDMA融合网络中鉴权与加密关键技术和TD-LTE的鉴权与加密原则,其次讨论USIM卡在GSM\TD-SCDMA\TD-LTE网络中互操作时的鉴权与加密需求,最后提出利用UDC HLR解决方案建设GSM\TD-SCMDA\TD-LTE融合用户数据库解决USIM卡在GSM\TD-SCDMA\TD-LTE互操作时的接入网安全问题。     

TD-SCDMA/GSM/GPRS双模终端CELL CHANGE ORDER过程研究

随着TD-SCDMA系统的商用,同时需兼容已非常成熟运营的GSM系统,TD-SCDMA/GSM/GPRS双模终端已是市场的主流。本文针对双模单待终端（协议控制）CELL CHANGE ORDER过程进行研究,该过程是双模终端实现PS域切换的一种重要方式。首先,以TD-SCDMA/GSM/GPRS系统高层协议为基础介绍了双模单待自动切换终端的CELL CHANGE ORDER过程的各个阶段：系统间测量、网络判决及小区改变执行;然后详细地设计了小区改变执行的正常及异常处理流程,并对如何实现数据平面切换过程进行了重点描述;最后搭建板级测试环境,进行协议一致性测试,验证了CELL CHANGE ORDER过程的实现。     

Novel Dual-Mode Dual-Band Filters Using Coplanar-Waveguide-Fed Ring Resonators

This paper presents a novel approach for designing dual-mode dual-band bandpass filters with independently controlled center frequencies and bandwidths. Two microstrip perturbed ring resonators are employed to obtain dual-mode dual-band responses. Novel feeding structures are introduced to simultaneously feed the ring resonators and conveniently control the coupling strength between resonators and feeding lines, resulting in a wide tunable range of external quality factors. Two kinds of filter configurations with compact size are proposed. Both of them provide sufficient degrees of freedom to satisfy various requirements of external qualify factors and coupling coefficients at both passbands. Therefore, the center frequencies and fractional bandwidths of both passbands can be independently tuned to desired specifications within a wide range. To verify the proposed method, four filters are implemented. The measured results exhibit dual-mode dual-band bandpass responses with high selectivity.     

Miniature built-in multiband antennas for mobile handsets

In this paper, we propose a new design for built-in handset antennas in that metal strips as additional resonators are directly connected with a feed strip. With the new design scheme, a quad-band antenna for covering GSM900, DCS1800, PCS1900, and UMTS2000 bands and a five-band antenna for covering GSM900, DCS1800, PCS1900, UMTS2000, and ISM2450 bands for use in mobile built-in handsets are experimentally carried out. Compared with the parasitic form with a shorted strip placed away from the main radiator in the open literature, the size of the proposed antennas can be reduced by an order of 10/spl sim/20%, which is desirable since the size of mobile phones is becoming smaller according to consumer preferences. Moreover, the impedance matching for each band of the new antennas becomes easy. The new quad-band and five-band built-in handset antennas are developed within the limits of a 36/spl times/16/spl times/8 mm/sup 3/ volume. The antennas are also analyzed using the finite-difference time-domain technique. A good agreement is achieved between measurement and simulation.     

Privileged Treatment of UMTS Subscribers in GSM Networks

Different user segments have various requirements and expectations towards the performance of mobile networks. Subscribers having experienced the high quality of UMTS networks desire to maintain high speech quality and excellent data throughput also in areas of missing UMTS but existing GSM coverage. In GSM networks a privileged treatment of UMTS subscribers by means of proper resource allocation provides a substantial quality improvement with respect to standard GSM subscribers. This strategy allows network operators to reduce the performance gap between both network areas experienced by UMTS subscribers. A detailed study on the performance of circuit switched speech and packet data services has been performed based on system level simulations. The results show significant speech quality advantages for users with dual-RAT terminals compared to standard GSM users as well as notably higher data throughput rates.     

GSM省级网管系统的功能分析

目前，我国各省、直辖市和自治区均建立了ＧＳＭ网，并实现国内国际漫游，全网用户数也超过了１４００万。在这种形势下，尽快建成各省（直辖市和自治区）的ＧＳＭ网络系统，对于改善网路运行是非常必要的。本文对ＧＳＭ省级网管系统的网络监视、资源配置和告警等网管功能进行了详细的介绍和分析。     

GSM向3G演进系统安全的改进

介绍了GSM向3G过渡时期GSM用户的认证与密钥协商过程,分析了GSM用户对3G系统的安全威胁,并对GSM用户接入3G系统提出了改进认证与加密算法。它可以有效防止攻击者假冒合法GSM用户滥用UTRAN网络资源,并可以保证用户的通信安全。     

一种基于DGS结构的新型双模双通带滤波器

提出了一种新颖的基于缺陷地结构(DGS)的双模双通带滤波器.该滤波器由印制板顶面的一个方形谐振单元和另一个巧妙嵌入在印制板底面DGS中的方形谐振单元并联构成,具有结构紧凑、易于加工的特点.每个谐振单元都具有双模单通带传输特性,可通过公共馈线同时激励实现双模双通带滤波.两个谐振单元的谐振频率相对可调,提高了设计上的灵活性.为减少辐射损耗并改善高频通带插损,使用准共面波导缺陷地结构对底面谐振单元进行了改进.最后,实验制作了两种双模双通带滤波器,测试结果与仿真结果吻合较好.     

折/衍共口径红外双波段位标指示器光学系统设计

针对反射式双模位标指示器视场小、中心遮拦、能量低等问题,提出一种折/衍共口径红外双波段位标指示器光学系统。基于消色差理论和MRTD模型分别推导了光学系统波段间消色差公式和作用距离方程。设计的双波段光学系统具有共焦距特性,从而实现了双波段同步探测以及识别目标信息的一致性。折/衍共口径红外双波段位标指示器光学系统工作波长为3.4~4.8 m、7.7~9.5 m,俯仰、偏航视场为-26~26,焦距115 mm,F数为2。结果表明:在-40~60℃温度范围内消热差,成像质量接近衍射极限。