一种基于新一代蜂窝移动通信的无线资源分配方案

新一代的蜂窝移动通信系统要求支持多种业务,从高质量的交互式实时业务到基于TCP连接的完全可靠服务。对于现有的无线链路,用户各种业务量的增加造成无线资源相对使用不平衡,大大降低了无线网络的吞吐量。本文提出了一种基于新一代蜂窝通信的无线资源分配方案,并利用OPNET建立仿真平台对该方案进行验证。仿真结果表明,各种不同优先等级的业务都能得到自己满意的服务质量,链路总的吞吐量达到了1 0 0 Mbit/s     

Terminal-to-Terminal Calling for GEO Broadband Mobile Satellite Communication

Satellite and terrestrial components of IMT?Advanced need to be integrated so that the traditional strengths of each compo?nent can be fully exploited. LTE/LTE?A is now a recognized foundation of terre...     

卫星移动通信系统星间链路设计

通过对现有的卫星移动通信系统星间链路的分析发现 ,不但卫星移动通信系统星间链路的指向具有周期性变化的特性 ,而且星间链路的相对距离也在周期性变化。这种星间链路指向的周期性规律变化 ,为星间通信链路的搜索建立以及星间通信设备的设计制造提供了研究的方向和理论依据。对星间链路的误码率的分析 ,主要探讨了由于卫星星体振动而引起的通信误码与振动的标准偏差 (幅度 )、通信所使用的光波波长、发射到接收的距离以及激光波束半径之间的关系 ,为实际星间链路的设计打下了坚实的理论基础。     

一种基于新一代蜂窝移动通信的链路自适应方案

本文介绍了一种基于新一代蜂窝移动通信系统(简称4G)的链路自适应方案,能够很好的保证链路高吞吐量,而且有效抵抗突发误帧,使链路ARQ负荷相对很小;同时有效的提高了频带资源的利用率。     

一种用于移动通信的无线电多媒体DSP芯片的实现

叙述了一种用于移动通信的无线电多媒体DSP芯片的实现。开发出的WM DSP芯片既支持用于Viterbi、时间同步等的通信指令,也支持多媒体指令。这个DSP能够处理可变长数据,并且在一个周期里可以执行4个MAC。提出的DSP采用了并行处理技术,如SIMD、矢量处理和DSP结构,并且采用了无线电应用的低功耗特性。整个DSP芯片包括测试电路和各种外围设备,如DMA、总线仲裁、定时器等等。除了存储器之外总共大约有170 000个门电路,并且时钟频率达到了100 MHz。     

固定宽带无线接入与移动宽带无线接入的比较

现今,信息通信从窄带向宽带、从有线向无线转变乃大势所趋。随着中国各运营商通信网络的迅猛发展,用户对网络的平均服务质量要求也越来越高,宽带无线接入技术作为一种有效的宽带解决方案而普遍地受到了人们的重视。那么,固定宽带无线接入与移动宽带无线接入有什么不同呢?本文首先在研究了固定宽带无线接入系统与移动宽带无线接入系统的网络结构后,重点讨论了两者的不同之处,即做了一个对比研究。希望能给相关人员有所参考。     

适用于移动通信的宽频带微带天线

该文研究新型的宽频带微带天线,采用一种具有双层贴片结构的微带天线的形式,并用在探针顶端加电容性金属圆片来抵消探针感性的方法,增加了天线的工作带宽。制作适用于第二代和第三代移动通信的宽频带微带天线,测试结果显示天线具有良好的带宽特性,能够满足移动通信系统对天线的带宽要求。     

公安交通指挥通信系统

建设以车载卫星移动通信为核心的交通指挥通信系统,对于提升道路交通管理水平,提高交通管理部门的快速反应能力和综合处置能力是非常必要的。介绍以卫星移动通信为核心的交通指挥通信系统的组成、系统网络结构、链路预算、系统设备配置和各种功能,并详细描述了终端IP网络的构建。     

Packet Design and Signal Processing for OFDM-Based Mobile Broadband Wireless Communication Systems

We consider improving the performance of orthogonal frequency-division multiplexing (OFDM)-based mobile broadband wireless communication (MBWC) systems. We show that a recently approved packet-based MBWC standard can cause the resulting systems to suffer from severe performance degradations for time-varying channels due to the lack of a mechanism for tracking the time-varying channels needed for coherent detection. We consider both packet design and signal processing to deal with time-varying channels. For the packet design, we segment an entire packet into multiple subpackets—with each subpacket having zero tail bits to reset the convolutional channel encoder—so that the detection/decoding result of each subpacket can be used to update the channel response for this subpacket. For signal processing, we use weighted polynomial fitting and prediction at the receiver to improve the channel tracking accuracy. Simulation results show that the coherent detection based on our new scheme can significantly outperform the commonly suggested differential modulation/detection methods.     

无线多媒体通信技术和系统

文章基于能提供广泛应用的高速无线多媒体通信技术和系统的研究、开发情况,介绍和讨论了无线多媒体通信的体系结构、关键技术、典型系统和它的应用前景。     

Large Antenna Array with Hybrid Beamforming System for 5G Outdoor Mobile Broadband Communication Deployments

Millimeter wave (mmWave) communication requires large antenna arrays to increase the capability of cellular networks of the fifth generation with good beam-forming gains and a substantial reduction in path losses for both transmitting and receiving terminals. As large antenna arrays require one radio frequency chain per antenna element, the fully digital beamforming technique results in high cost and high-power consumption, and it is therefore not feasible. However, in analog solutions, adaptive gain control cannot be used as it reduces the likelihood of advanced processing and contributes to poor efficiency. Hybrid schemes are possible exciting solutions that overcome the deficiencies of pure digital or analog beam forming. The following are the three key contributions of the proposed work: a typical link budget specification for target data rate 3.10 Gbps in downlink and 0.6 Gbps in uplink is provided, micro strip patch antenna with a single element is designed to operate at 28 GHz and then converted into a standard linear array and a Kalman-based hybrid analog/digital precoding is used with a downlink rate of 4.64 Gbps/cell and an uplink rate of 1.84 Gbps/cell in multi-user environments. And the influence of both base station (BS) and 5G User equipment (UEs) beam steering capability is also explored. From the simulation result, it is evident that the proposed work offers a substantial increase in spectral efficiency approximately 9.28 bps/Hz at 20 dB with 10 channel paths.

     

TD-SCDMA和WiMAX技术融合实现宽带无线移动通信系统

本文主要论述了基于TD-SCDMA和WiMAX技术融合实现一种新型的宽带无线移动通信系统。在该系统中,TD-SCDMA接入网提供广域无线覆盖,支持高移动性,提供话音业务和中、低速数据业务;WiMAX接入网提供热点区域覆盖,支持游牧移动性,提供高带宽流媒体数据服务,两种接入技术在网络层实现汇聚,通过网络层移动性管理技术,共享核心网络和业务系统,实现两种接入网的统一的无线资源管理以及统一的用户管理和计费,移动终端可以在该系统下的两种网络之间实现无缝漫游和切换。该种新型的移动通信系统能够很好的满足用户对移动通信业务的使用要求,也能够有力支持TD-SCDMA大规模独立组网,增强TD-SCDMA的竞争力;同时,也为TD-SCDMA系统的演进和跨越式发展提出新的思路。     

非视距传输关键技术及其在宽带无线接入中的应用

随着无线接入系统的工作频段越来越高,传输带宽越来越宽,非视距(Non Light Of Sight,NLOS)传输的限制就越来越大.研究非视距传播环境下抗衰落技术,对解决非视距无线接入条件下系统的可靠性和有效性,提高工程应用能力具有重要意义.非视距传输的关键实际上是抗多径衰落技术,包括OFDM、收发分集、子信道化、智能天线和自适应调制等技术.在分析非视距传播的条件和影响的基础上,对解决非视距传输问题的几个关键技术进行讨论,并对其在象WiMAX这样的宽带无线接入中的应用优势和影响进行了分析.     

宽带无线IP技术与系统

文章列述了宽带无线IP技术发展的概况,介绍了中国宽带无线IP技术标准化的工作,最后以宽带IP实验系统为例说明了这一技术的应用。     

有线-无线混合IP网络多媒体传输算法研究

提出了一种端到端的在异构的有线．无线混合IP网络上多媒体传输的改进算法WMTA（wireless multimedia transmission algorithm）。通过研究Gilbert无线差错模型仿真环境中包的长度与丢包率的关系,发现包长与丢包率呈线性增长的关系。基于上述观察,算法通过交替发送大小数据包探测随机和拥塞丢包数,并根据两种丢包的程度进行速率控制。针对不同网络状态转换时算法更新慢的缺点,添加了更新因子K,使算法在网络状态转换时能迅速适应当前网络的状态。仿真结果表明,与现有算法相比,WMTA无论是在运行单个流还是存在竞争流情况下,都能够达到更高的吞吐量和带宽利用率,有效地提高了网络中多媒体传输的服务质量（QoS）。     

Unified Radio Network for Broadcasting and Broadband Wireless Access [Advances in Mobile Multimedia]

In this article we propose a unified radio network architecture, broadband wireless multimedia (BWM), which integrates broadcasting service and broadband wireless access service at both the application and physical layers. A simple, flexible, and comprehensive radio resource management framework is developed for the unified radio network. It is shown that the proposed radio network architecture has many advantages over existing ones. In addition, the new architecture is currently being considered in China for the system level design.     

固定无线接入系统对卫星地球站的干扰分析

为了使共用同一频段的3.5 GHz固定无线接入系统（FWA）和C波段固定卫星业务（FSS）实现共存,就需要对这两个系统间的干扰进行分析。采用确定性计算方法主要研究了在建筑物密集但排列比较整齐的地形中3.5 GHz固定无线接入系统对C波段卫星地球站产生的同频干扰,给出了同频干扰的计算方法,并进行了仿真分析,从而验证了在这种地形下实现两系统干扰共存的可行性。     

一种语音业务固定无线接入方案

固定无线接入系统中语音业务的接入方法进行了研究,介绍了固定无线接入系统的结构,分析了当前广泛采用的V5接口的优缺点,提出了一种基于ISDN一次群速率接口的接入方案并给出了其具体实现方法。     

A Hybrid Adaptive Wireless Channel Access Protocol for Multimedia Personal Communication Systems

This paper proposes a new medium access protocol (MAC) protocol for futurewireless multimedia personal communication systems, denoted hybrid andadaptive multiple access control (HAMAC) protocol. The HAMAC protocolintegrates fixed assignment TDMA protocol, reservation-based protocols, andcontention-based protocols into a single wireless network so as tosimultaneously and efficiently support various classes of traffic such asconstant-bit-rate (CBR), variable-bit-rate (VBR), and available-bit-rate (ABR)traffic. In particular, the HAMAC protocol uses a novel preservationslot technique to overcome the packet contention overhead in packetreservation multiple access (PRMA) like protocols, while keeping mostisochronous service features of TDMA protocols to serve voice and CBR trafficstreams. A preservation slot is a very short slot which is used torepresent a CBR connection when the traffic in the CBR connection is in asilent period in which there is no meaningful data to transmit. Due to thevery short length of the preservation slot, it only takes minimalportion of the bandwidth pre-allocated to the CBR connection, so that theremaining bandwidth can be freed for other connections to use. When the CBRsource becomes active again, the preservation slot is replaced bynormal data slots without any reservation operation, extra delay, orsignificant bandwidth loss. Consequently, the guaranteed service andsimplified signaling features of TDMA protocols, together with the adaptivebandwidth allocation features of PRMA-like protocols, are both realized in theHAMAC protocol. We have analyzed the performance of the HAMAC protocol usingextensive simulations. The results show that the HAMAC protocol can achievevery low loss rates for various multimedia traffic with stringent quality ofservice (QoS) requirements and outperforms state-of-the-art PRMA-likeprotocols. As a result, the HAMAC protocol appears to be a good candidate forfuture generation multimedia personal communication systems.     

基于照明灯及电力线为载体的新型宽带移动通信系统

适应未来宽带移动通信的发展要求,解决目前制约移动通信快速发展的4个“瓶颈”性难题,可以采用一种全新的以信息灯为接入点的移动通信网络形式。信息灯是一种具有普通照明功能且能实现部分无线信号收发功能的新型装置,通过与之相连的电力线（或者光纤）实现接入点与接入网的信息交互。基于信息灯的网络架构以多天线分布式空时信号处理和资源管理为核心支撑技术,通过有线网络和无线网络的有机融合,提供高速、高质量的移动通信服务。