基于模糊层次分析的多天线系统性能评估

针对多输入多输出/智能天线（MIMO/SA）多天线系统,分析了影响系统性能的各个因素,建立基于模糊层次分析法的结构模型,确定各指标的权重,然后利用模糊数学原理得到结合方案中各指标的隶属度,得出各方案性能的模糊综合评估。仿真结果验证了该评估方法的准确性与有效性,对MIMO/SA技术的结合与应用提供了很好的参考和决策支持。     

软件无线电在智能天线中的应用

针对无线通信领域中存在的多种通信体系共存,各种标准竞争激烈等问题提出软件无线电技术。简述软件无线电的概念及功能特点,介绍了目前软件无线电的研究状况及无线电的关键技术之一———智能天线,采用软件无线电和智能天线融合的方法研究,较好地解决了体系共存和频带资源使用问题,理论和实践均取得了较好的效果,目前已得到了广泛的应用。     

Identification of Radio Environments in Software Antenna for High-Speed Millimeter Wave Wireless Communication Systems

Different from smart antenna, software antenna can cope with various radio environments by selecting appropriate algorithms. In this paper, we place emphasis on the identification of radio environments in software antenna for high-speed millimeter wave wireless communication systems. According to the major impairments of radio propagation and the limitation of the adaptive algorithms, we give a criterion to categorize the environments. A spatial smoothing method to identify the environments is also proposed.     

SCA架构软件无线电台设计与实现

为提高数字通信电台的通用性、灵活性和重构性,提出了一种基于软件通信体系结构（SCA）的软件无线电台的设计方案,给出该方案的工程实现方法,并以超短波跳频波形为例讲述了基于该软件无线电台的应用波形和组件的开发过程。该方案可为基于SCA架构的便携式软件无线电台的设计和开发提高参考。     

Software radio architecture with smart antennas: a tutorial onalgorithms and complexity

There has been considerable interest in using antenna arrays in wireless communication networks to increase the capacity and decrease the cochannel interference. Adaptive beamforming with smart antennas at the receiver increases the carrier-to-interference ratio (CIR) in a wireless link. This paper considers a wireless network with beamforming capabilities at the receiver which allows two or more transmitters to share the same channel to communicate with the base station. The concrete computational complexity and algorithm structure of a base station are considered in terms of a software radio system model, initially with an omnidirectional antenna. The software radio computational model is then expanded to characterize a network with smart antennas. The application of the software radio smart antenna is demonstrated through two examples. First, traffic improvement in a network with a smart antenna is considered, and the implementation of a hand-off algorithm in the software radio is presented. The blocking probabilities of the calls and total carried traffic in the system under different traffic policies are derived. The analytical and numerical results show that adaptive beamforming at the receiver reduces the probability of blocking and forced termination of the calls and increases the total carried traffic in the system. Then, a joint beamforming and power control algorithm is implemented in a software radio smart antenna in a CDMA network. This shows that, by using smart antennas, each user can transmit with much lower power, and therefore the system capacity increases significantly     

基于SCA的认知无线电台结构研究

认知无线电作为一种智能无线电技术,可赋予无线通信系统以电磁环境感知能力,有效解决频谱利用率和管理的问题.软件通信体系结构(简称SCA)已被软件无线电论坛采纳为嵌入式系统的标准通信软件结构.SCA提供了一种支持通信软件和硬件可移植、可配置、可扩充和可重用的软件平台.本文首先论述了认知无线电的概念、功能,接着结合开源认知无线电的概念,提出了一种基于SCA的认知无线电台的新结构,并进行了详细的阐述.     

Understanding the software communications architecture - [topics in radio communications]

The Software Communications Architecture is an open architecture developed by the U.S. Department of Defense to standardize the development of software-defined radio, improve communication systems interoperability, and reduce development and deployment costs. The SCA facilitates software reuse and technology insertion by abstracting radio applications from the supporting platform and defining a common operational environment across platforms. The SCA relies on commercial standards, classic software engineering principles, and software design patterns. While some SCA design choices are controversial and tightly tied to the specific needs for which it was developed, the basic design principles of software reuse and abstraction are sound and necessary if SDR is to achieve its full potential. Some of the techniques and concepts used in the SCA may be foreign to a communications engineer, and can result in confusion and long learning curves. The understanding of these concepts is of great relevance for communications engineers independent of any opinion about the SCA itself. This tutorial is aimed at educating communication engineers on these software engineering principles and describing how the SCA applies them to achieve its goals. We describe the different interfaces of the SCA that provide a framework for the implementation of SDR. The tutorial provides introductory material to understand the basic operation of the SCA as implemented in the Open-Source SCA Implementation::Embedded developed by Wireless @ Virginia Tech.     

二维定向瑞克接收机实现方案比较研究

为了充分利用瑞克（RAKE）接收机的多径能量利用效果和智能天线（SA）的定向收发作用,研究了RAKE接收机和智能天线的联合使用,提出了基于智能天线的定向二维（2D） RAKE接收机模型,给出了定向2D-RAKE接收机分别在射频、中频和基带的实现框图、工作原理和输出信号表达式,并对它们的性能以及工程实现做了分析讨论。指出基带定向二维RAKE接收机由于可以在基带上通过幅度加权来实现信号的定向收发,其优点是可以利用目前比较成熟的基带信号处理技术,但是由于不能利用相干解调作用来抑制多径干扰（MPI）和多用户干扰（MAI）,存在噪声放大问题;射频定向二维RAKE接收机的信噪比增益最大,但工程实现难度较大;中频定向二维RAKE接收机则具有较高的性价比。     

基于Direct Play API的语音通信系统实现

阐述了语音通信系统基于微软DirectPlayAPI开发通信软件,通过对网络结构和语音编码的详细分析和研究,成功地在多台飞行模拟器之间建立起独立的语音通信网络;为保证飞行模拟器声音仿真的完整性,语音通信计算机在完成语音数据交换的同时完成单机电台罗盘声、语音告警等声音的仿真。     

Investigation of capacity and call admission control schemes in TD‐SCDMA uplink systems employing smart antenna techniques

Due to the TDMA (time division multiple access)/time division duplex (TDD) specialization in the uplink (UL) of code division multiplex access (CDMA) systems, some advanced techniques, such as smart antenna (SA) and multi‐user detection (MUD), are utilized conveniently in time division‐synchronous code division multiplex access (TD‐SCDMA) systems. These advanced techniques have great impacts on the capacity and radio resource management (RRM) schemes. In this paper, the UL capacity and load models specified for TD‐SCDMA systems are proposed, in which the impacts from SA and MUD techniques are considered, and the UL load can be estimated based on the total received power in the base station. According to the proposed theoretical capacity and load evaluation models, the call admission control (CAC) strategies suitable for TD‐SCDMA systems are presented. Since there are two kinds of SA schemes (i.e., tracking beam antenna (TBA) and switched beam antenna (SBA)) utilized in TD‐SCDMA systems, the efficient CAC algorithms suitable for these two SA schemes are designed and evaluated, which are based on principles of the interference increase estimation. All simulation results show that the proposed CAC strategies can work efficiently and improve performances of TD‐SCDMA systems dramatically. Copyright © 2009 John Wiley & Sons, Ltd.     

电台软件架构发展及其向SCA4．0演进的途径分析

使用标准的软件架构能够实现波形应用的硬件无关设计,也便于电台软件走向分层开放的合作设计。采用软件通信体系结构SCA,能够实现电台软件的标准化、平台化、智能化。首先对SCA在国内外的发展与应用现状进行了介绍,在基于主流的SCA2．2规范进行的SCA电台软件开发经验的基础上,探讨了SCA4．0架构的特点,提出了把核心框架、平台、波形从SCA2．2架构升级到SCA4．0架构的途径,思考了基于SCA架构的电台软件未来发展趋势。     

当前移动通信中的关键技术

目前,第三代移动通信系统已在多个国家建设或运营。本文针对第三代移动通信中的四种关键技术——多用户检测、功率控制、智能天线和软件无线电——做了简要介绍,分析了其形成原因和作用,并阐述了其基本原理。     

Open-Source SCA-Based Core Framework and Rapid Development Tools Enable Software-Defined Radio Education and Research

This article describes the Open Source SCA Implementation::Embedded project, an open source software development kit designed for rapid prototyping of software defined radios consistent with the software communications architecture. The SCA is a product of the American military's SDR acquisition program and has played a large role in SDR development in the military and in the wireless industry. OSSIE was designed for use in wireless communications curricula and research efforts, so it is easy to learn and illustrative of software engineering, programming, and communications engineering concepts important in industrial practice today. OSSIE includes a core framework (i.e., common services enumerated in the SCA). It also includes graphical user interface-oriented tools that are easily learned and free to download and use. The tools auto-generate SCA-specific component source code and supporting files, leaving the developer to provide signal processing functionality. In addition, visualization tools for debugging and a growing library of SDR software components are available. Discussed herein are examples of SDRs designed using OSSIE, including embedded applications. OSSIE enables easy transition from concepts to practice in SDR design for communications engineers who may not have a strong software background.     

Design and rapid prototyping of SCA-compliant public safety P25 waveform and P25?CFM3TR?CVoIP bridge

Establishing radio communication between military commanders, soldiers and law enforcement officers is an important enabling capability to facilitate interoperability. The Joint Tactical Radio System (JTRS) program is enabling communications within the military by implementing different military radio waveforms on software defined radio (SDR) platforms. It is logical to include a Project 25 (P25) public safety waveform in the JTRS waveform portfolio. This paper describes the rapid development of a P25 waveform on a surrogate JTRS SDR platform. The development process and methodology, which starts from a platform agnostic executable waveform model in Matlab, through an intermediate implementation using open tools on generic platforms, to the final platform-specific implementation, is introduced and discussed. This paper shows that adopting this methodology can speed up waveform development and porting. Furthermore, this paper presents the design and implementation of a three way voice bridge among P25, the future multiband multiwaveform modular tactical radio (FM3TR), and voice over Internet Protocol (VoIP), with software communication architecture (SCA) compliant implementation for both the P25 and FM3TR waveforms. This paper shows that critical issues such as interoperability can be tackled efficiently by leveraging SDR and SCA.     

软件无线电技术在3G中的应用

文章首先概括地介绍了软件无线电的概念、实现的体系结构和关键技术,然后针对3G标准的大带宽、高速率、多媒体要求以及采用智能天线、多用户检测、Turbo码等技术带来的挑战,重点讨论了3G系统中采用软件无线电技术的难点及当前的进展情况。     

Evolution and standardization of the smart antenna system for software defined radio

Transitioning proprietary or legacy software defined radio networks to open architectures, while often complicated, is increasingly critical to improve the interoperability and compatibility among SDR networks and the subsystems within those networks as well. With this in mind, two consortia, the SDR Forum and the Object Management Group, have teamed to define an open Smart Antenna specification. This specification defines a model (including an API) that simplifies the integration of an SA subsystem into a traditional SDR network. The specification is called the "Platform Independent Model (PIM) and Platform Specific Model (PSM) for the Smart Antenna" or "SA API specification." This article introduces the SA API, which provides a standard model and standard service of the SA system operating in SDR networks.     

Experimental studies of direction of arrivals using a smart antenna testbed in wireless communication systems

This paper presents some preliminary results from experimental studies on space‐division‐multiple‐access (SDMA) for wireless communications. A smart antenna system utilizing direction‐of‐arrival (DOA)‐based beamforming techniques can enhance signal quality by reducing co‐channel interference from mobiles located at angles spatially distinct from the base station. Adopting both smart uplink and downlink beamforming, a communication system with an antenna array can increase the cell coverage of a base station and significantly boost capacity compared with conventional antenna systems. However, successful implementation of DOA‐based beamforming techniques depends on the DOA characteristics. This paper presented the feasibility of direction finding and DOA variation with respect to frequency. Furthermore, the angle spread was studied for selected environments. The results demonstrate the feasibility of applying proposed smart antenna system utilizing DOA‐based beamforming algorithm for increasing channel capacity and improving system performance in frequency‐division‐duplex (FDD) wireless communication systems. Copyright © 2003 John Wiley & Sons, Ltd.     

Modeling of the XOM/XMP application programming interface (API)

With the growing complexity of communication protocols, it is increasingly difficult for application developers to interface the applications to the communication stacks across a number of platforms. A common application program interface (API) is needed for the purpose. The API can effectively conceal the complexities of communication protocols and architecture, making it easier for application development. This article presents the modeling and development of a generic API, XOM and an application-specific API, XMP. XOM API provides a general-purpose data handling mechanism and XMP API provides service primitives to network management protocols. The development is based on object-oriented technology. The attractiveness of object-oriented implementation is its ability to provide encapsulation, reusability and extensibility in the software modules. The benefits and difficulties encountered during the implementation are to be discussed. The experience will be useful for API development     

Radio propagation and anti-multipath techniques in the WINenvironment

The unique characteristics of wireless in-building network (WIN) systems based on microwave radio technology are addressed, focusing on the multipath propagation problem which most distinguishes radio from wired LAN media. This is followed by a discussion of the three principal techniques that have been developed within the radio communication industry to deal with this multipath problem: adaptive equalization, spread spectrum, and antenna diversity. A review of the strengths and weaknesses of each of these techniques reveals that antenna diversity is clearly the preferred choice for use in WIN systems operating in the recently allocated spectrum near 18 GHz. An example of such an antenna system is examined. It is shown how these multiple, directional antenna systems function in three types of environment     

基于软件无线电技术的第三代移动通信

简要介绍了软件无线电的概念 ,并较详细探讨了软件无线电在第三代移动通信系统的计算机化、实时操作系统、智能天线和移动终端方面的应用。