CDMA上行链路功率控制函数对系统容量的影响

根据对ＣＤＭＡ蜂窝系统上行链路干扰模型的分析，导出了行链路功率控制函数与系统容量之间的关系式，计算机模拟结果表明，与其它几个常用的功率函数相比，由本提出了使下行链路系统容量最大的最佳功率控制函数不使上行链路系统量最大，而且还比下行时的系统容量大１．４倍左右。     

具有双层系统的分扇区CDMA小区上行链路容量

码分多址系统与传统的时分多址和频分多址系统相比,在各方面都具有优势,尤其是能提供更好的服务质量和更大容量,因而成为第三代移动通信系统的核心技术。通过在小区中划分扇区能进一步提升系统容量,在扇区中又引入双层系统,可以显著提高该扇区内容量。由于CDMA系统是噪声受限系统,因此以信干比为标准,分析具有双层系统的分扇区CDMA小区系统的上行链路容量。最后通过仿真结果证明了该系统上行链路容量相对普通小区系统上行链路容量的提升。     

电磁辐射对移动通信系统影响的研究

本文从电磁辐射对人体影响的角度分析了移动通信系统的传输特性,论证了在电磁辐射约束的条件下.单用户的上行链路相对于单用户的下行链路更容易达到传输能力饱和.随着上下行链路传输能力的增长.系统将会越来越表现出单用户的上行容量受限,而单用户的下行链路却拥有更大的传输速率余量和更大的发射功率余量,单用户的上下行链路具有显著的非对称传输特性,并在此基础上探讨了提高上行链路传输容量的方法.     

CDMA低轨道卫星移动通信系统的容量分析

通过对低轨道卫星移动通信系统的上行链路和下行链路的分析,定性介绍系统在不同状态下的容量关系     

Adaptive Antenna和Switched Beam相结合的新型智能天线

提出了一种上行链路采用Adaptive Beam,下行链路采用Switched Beam的新颖智能天线.其中上行链路是通过由信道估计得到的导向矢量形成指向各用户的Adaptive Beam,下行链路则是通过估计得到的用户分布形成Switched Beam.该智能天线系统既可以抑制上行链路中多用户信号的干扰,也可以使下行波束易于对准用户,使系统有尽可能高的容量且便于实现.     

LTE系统中多用户MIMO容量分析

首先简单介绍了LTE通信技术,在此基础上分析单用户MIMO系统容量以及相应的功率分配问题,随后对多用户MIMO系统功率分配问题做了简单介绍,并给出上行链路和下行链路的容量区域表达式,最后给出4种信道情况下容量之间的关系。     

WCDMA中单载波系统上行链路性能仿真分析

针对WCDMA中单载波系统布局、上行链路的容量与覆盖诸方面因素进行了比较深入的分析，通过仿真得到相应的结论。     

宽带CDMA上行链路含导频信号的调制方式的性能分析

研究了宽带 Ｃ Ｄ Ｍ Ａ 上行链路含有导频信道／导频符号的调制方式,分别给出相应的相干解调模型。分析和比较,含导频信道／导频符号的相干解调与非相干解调的性能。并推导出导频信号功率占信号总功率的比例与所获信噪比增益大小,及与系统容量关系。表明宽带 Ｃ Ｄ Ｍ Ａ 在上行链路采用含导频的相干解调技术,可以带来上行链路容量的提高。     

3G无线网络覆盖和容量的规划设计

随着我国3G系统建设的全面启动,3G网络规划设计已成为研究的热点之一。为了实现建设目标,在进行3G无线网络规划设计时,必须同时考虑覆盖、容量及不同服务质量的要求。文章对无线网络覆盖和容量的规划设计进行了论述,分析了覆盖和容量的关系,讨论了覆盖规划、容量规划等几个重要问题。特别对链路预算、传播模型、容量估算和极限容量等进行了阐述,给出了上行极限容量分析及上行链路容量规划的举例。     

多媒体CDMA系统在功率约束条件下的业务容量分析

码分多址接入（CDMA）技术可以灵活地支持无线多媒体业务传输。该文分析了多小区环境下CDMA系统上行链路的多媒体业务容量，主要讨论了用户最大发射功率约束条件在不同用户激活因子情况下对系统容量的影响。分析和计算结果表明用户最大发射功率约束使系统的容量有所降低。     

分布天线系统--一种新的热点区域容量解决方案

分布天线系统是后3G系统的主要研究方向之一,具有高系统容量与系统配置灵活的特性,本文提出了采用在WCDMA宏蜂窝网络中配置分布天线系统的方式来解决热点区域容量问题,分析与仿真结果表明在WCDMA宏蜂窝网络中配置分布天线系统是解决热点区域覆盖与容量问题的理想解决方案之一.     

Simulation,implementation and performance evaluation of a diversity enabled WCDMA mobile terminal

Smart antenna array technology has been shown to greatly improve the performance of wireless communication systems. In this article, we describe the impact of smart antenna array processing at the mobile terminal for Wideband Code Division Multiple Access (WCDMA) cellular networks. Using system simulations we demonstrate the quality of service, network coverage, and network capacity improvement provided by a WCDMA dual antenna receiver and we establish a relationship between this improvement and the link level performance. We then describe a receiver architecture for a dual antenna WCDMA mobile receiver. The proposed receiver was implemented, as part of a complete mobile terminal solution, in an ASIC using a 0.18 μm, 1.8 V CMOS technology. The ASIC was integrated with RF, analog and digital components in a PCMCIA card form factor. The PCMCIA is a 3GPP compliant user equipment and has been submitted to standardized performance and conformance tests. Experimental measurements gathered with the PCMCIA card illustrate the impact of a diversity enabled mobile data terminal on the link level performance. For various propagation environments and transmission data rates, improvements in the range of 2.7 – 10 dB in the required DPCH I _c/I _or for a 1% Block Error Rate (BLER) were observed. These measurements are within 1.4 dB of the ideal link level simulations which indicates that the predicted improvement at the network level should also materialize. The results presented in this paper show the tremendous potential of smart antenna arrays in 3G WCDMA cellular networks and establish diversity as a viable solution for high-speed cellular communications.     

Directional power-based admission control for WCDMA systems using beamforming antenna array systems

A directional power-based admission control (AC) scheme is proposed for base stations deploying beamforming antenna arrays. The proposed AC algorithm is a natural extension of the conventional power based AC scheme for cells using standard sector antennas. The directional scheme takes the load per beam/direction into account in the AC decision, so the cell load is controlled in accordance with the spatial filtering gain provided by using beamforming antenna arrays. The scheme is tested by means of Monte Carlo simulations in a multicell wideband code division multiple access (WCDMA) network, where users with different bit rates are present. The obtained results demonstrate that the directional power based AC scheme allows a higher traffic load in cells using beamforming antenna arrays without jeopardizing the stability of the network. Application of a four element antenna array is found to provide a capacity gain of a factor 2.7 for a network with many low bit rate users, while the gain is reduced to a factor 2.3 for traffic scenarios with a mixture of high and low bit rate users.     

智能天线及其提高移动通信系统容量的分析

采用智能天线,可以降低移动通信系统的同频干扰,增加移动通信系统容量。介绍了智能天线的基本原理及其在移动通信系统中的应用,建立了基于智能天线的同频干扰的统计模型,对智能天线提高移动通信系统容量进行了分析。     

WCDMA Uplink Capacity and Interference Statistics of Highways Shaped Microcells with Imperfect Power Control and Finite Transmitted Power

The capacity and the interference statistics (mean and variance) of the sectors of a Cigar-, Tee-, and Cross-shaped WCDMA microcells are studied. Models of 5, 7, and 9 microcells are used to analyze the uplink capacity of the cigar-, Tee-, and cross-shaped W-CDMA microcell, respectively. The capacity and the interference statistics of the microcell are studied for different sector range and antenna side lobe levels. It is shown that the highest sector capacity is obtained when the microcell is cigar-shaped. For a cross-shaped microcell, the sector capacity is the lowest. Also it is shown that the uplink sector capacity will be very high if synchronous WCDMA is used in the uplink. To get the quasi maximum capacity, the sector range should be (0.6 – 1) km and the side lobe level of the directive antenna used in each sector should be – 15 dBc or lower.     

多制式共存通信系统天线研究与设计

针对目前广泛使用的WCDMA系统中存在的多通信制式,先从理论上分析了多通信制式共存时干扰存在可能性,然后运用天线近场方程理论建立了WCDMA和WLAN两制式共存的终端模型。最后通过实际的仿真数据,给出了两制式共存系统避免彼此干扰的天线解决方案,在此基础上,又提出了多制式共存天线设计的具体措施和解决方案,为WCDMA移动终端中多通信制式共存终端设计提供了有利参考。     

Capacity gain of an uplink-synchronous WCDMA system under channelization code constraints

The performance of an uplink-synchronous wide-band code-division multiple-access (WCDMA) system is evaluated for radio environments with low temporal dispersion. The capacity gain of synchronous WCDMA is evaluated theoretically under certain constraints and by means of extensive dynamic system level simulations for more advanced scenarios. The effect of channelization code shortage, the impact of the dispersive radio channel on the orthogonality of received signals, and soft handover are some of the considered effects. The potential capacity gain is found to equal 35.8% in a multicell scenario, conditioned on an infinite number of channelization codes per cell. For a more realistic scenario with channelization code constraints, the capacity gain is reduced to 9.6%. The absolute number of users per cell, relative to the available number of channelization codes within each scrambling code group, is therefore found to be an important metric. This further suggests that the capacity gain of synchronous WCDMA decreases when other capacity-enhancing techniques are deployed, such as uplink antenna diversity, soft handover, voice activity detection, etc. The presented simulation results in the case where soft handover is not considered accurately match the analytical findings.     

Indoor Planning for High Speed Downlink Packet Access in WCDMA Cellular Network

The aim of this paper is to show the special characteristics of the indoor environment related to radio propagation and furthermore to radio network planning. The aspects of the radio network planning are highlighted especially for Wideband Code Division Multiple Access (WCDMA) radio access technology that is used widely in the third generation mobile networks. Moreover, the detailed planning parameters in indoor environment are studied for High Speed Downlink Packet Access (HSDPA) in order to support high throughput data applications in Universal Mobile Telecommunications System (UMTS). The final target of the paper is to compare pico cell, distributed antenna system (DAS), and radiating cable network configurations in indoor environment to provide the optimal radio conditions for the data applications, and thus to serve highest number of mobile users. Several measurement campaigns with different antenna configurations have been conducted in order to study the effect of multi path related parameters, as delay spread of the signal. Also other capacity related parameters as received signal levels, interference, throughput, and transmit power levels have been studied in order to find out the optimal solution for HSDPA in UMTS. The results clearly show that pico cells and distributed antenna system have outstanding performance in indoor propagation channel compared to radiating cable. In sense of signal quality, pico cell performance is slightly better compared to distributed antenna system. However, measurements with HSDPA indicate that practical capacity of DAS outperforms pico cells. The measurements also show that separation of the antennas is a key capacity related parameter when planning WCDMA based indoor systems.     

相关衰落信道上WCDMA系统的安全性能分析

对多输入多输出（MIMO）相关衰落信道上宽带码分多址接入（WCDMA）的安全性能进行评估,一种省时高效的解决方案是理论分析法。推导了相关 Nakagami 衰落信道上采用空时分组码和二维瑞克接收机（2D-Rake）的 WCDMA 系统的非零安全容量概率和安全中断概率的精确解析表达式。利用上述表达式,可以快速地评估收发天线数、天线相关系数、Nakagami衰落系数、平均路径衰减系数等参数对WCDMA系统安全性能造成的影响。数值计算和仿真结果相吻合,证明了以上理论分析的正确性。推导了WCDMA系统渐近安全中断概率的解析表达式。结果表明,WCDMA 系统的安全分集增益为主信道各个可分离路径上的分集增益之和,与窃听信道无关;对于恒定多径强度轮廓的同分布Nakagami衰落信道,WCDMA系统的安全分集增益为主信道的收/发天线数、多径个数以及Nakagami衰落系数四者之积。     

TD-SCDMA空中接口物理层概述及其与WCDMA的比较

对TD-SCDMA移动通信系统空中接口的物理层的帧结构,以及物理层所采用的智能天线,联合检测,动态信道分配等关键技术进行了阐述。并与WCDMA系统的空中接口物理层作了比较。为TD-SCDMA无线系统和WCDMA无线系统的研究提供一定的参考数据。