4-英语读书笔记—

英语读书笔记



无线电智能天线系统的演进和标准化

概述
软件无线网络到开放的结构的产权转移或者继承往往是复杂的，在SDR网和 其子系统
中，对复用性和协调性的提高也越来越重要。鉴于此，SDR论坛和对象管理小组联合制定了一个开放的智能天线的规范。这一规范定义了一种模式（包含一个API）简化了SA子系
统到传 统SDR网络的耦合。这一规范称为面向智能天线的平台无关模式（PIM）和平台专
一模式（PSM） 或者称为应用程序编程接口（SA API）。这篇文章介绍了SA API，
它提供了一个在SDR网中SA系统操作的标准模型和服务。
前 言
自从 19实际80年代初期，无线电产业已经随着多种和技术的发展而迅速成长。每个无
线标准都随着它所专 有的服务演进，如语音，视频，无线因特网传输或是电子邮件服务。这
种迅速发展迫使客户（开发者和终 端用户）在他们的各种需求中使用复合设备，这减少了设
备的生命周期。客户更喜欢使用有多种服务的单 一设备。对于终端用户的需求，生产厂商必
须寻找一种支持可伸缩、可移植、可重用、互操作性和生产效 率较高的开发技术。无线电产
业（包括金融、制造和国防）由于在容量需求标准和标准的工具支持的变化 而面临着开发的
变革。SDR可以使一个通用的无线电平台支持多标准和服务的动态更新（自动下载或者 其
他由各种客户提出的方式），还提供了应对变化的框架。
SDR解决方案是多种多样的，在 本文中我们涉及了两个相关的标准化基于软件的通用
无线平台和智能天线的软件接口标准的固定基础。
软件通信提醒的开发采用无线电系统连接策略（JTRS）和连接程序执行办公室（JPEO）。 软件无线电的平台无关模式（PIM）和平台相关模式（PSM）由对象管理小组开发，基
于SCA 连接OMG的模型驱动结构（MDA），如下描述：
第一，对于SCA，HTRS和JPEO的任务就 是开发一组交互性和可负担的SDR，提供安
全无线的通信网络。另外，SCA的目的是提高从一个JT RS到另一个的波形的可移植性。它
为SDR软件组件开发以最低要求建立了一种独立实现的框架。软件 组件提供了SCA应用程
序的管理和执行，SCA操作环境（OE）的定义设备组成。OE由核心框架（ CF），通用请求
代理（ORB）和基于操作系统 的便携式操作系统接口（POSIX）。正如SCA 规范中的定义，
CF在开放的应用层CORBA接口和提供底层系统软件和硬件的抽象服务服务是必需的 。
CORBA ORB是不同的系统实现分布式系统资源的分布式调用。
第二， SWRadio规范由OMG的软件通信工作小组（SBC-DTF ）开发，早期的支持
和资助的联合 无线电系统的JTRS和JPO还有其他持续参与各国防、商业和学术界的合作伙
伴。增强的便携SWR adio规范和重用的波形组成部分的规定，在SCA中为软件组件定义
PIM及PSM，包括标准的应 用编程接口（ API ） ，物理层，链路层控制（LLC），介质访
问控制（ MAC ）层和基于 OE的被定义为SCA的无线电管理。PIM及PSM的基本概念
是在OMG的MDA。MDA是一种解 耦的SDR软件模型的平台特异性部署技术（即开发语
言，中间件，操作系统，处理器类型等）。该SW Radio规范包含专业化的UML （称为UML
的简介）这是独特的软件无线电技术。该SWRad io规范的详细规格工具的买主必须遵循向
软件无线电社区提供应用。软件无线电社区使用这些工具建模 与实现他们的SDR和波形应
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用，还有基本SWRadio组成部分的应 用程序组件。使用工具和MDA的建模方法的意义在
于重用性，可携性及互操作性，目的是降低成本和缩 短以生产高质量和稳定的软件无线电的
交付时间。
最后，SWRadio规范中MDA的能力 作为一个高度容纳基础无线电设备和服务，如SA
技术。
然而，SCA和SWRadio规范 都不支持SA技术，而在一个优质的无线系统中这又是比
不可少的元素。作为SDR论坛的成员，认识到 了SA在优质无线系统中的重要性，智能天
线工作组（SAWG）由SDR论坛的专门委员会组成。此工 作小组的证书中规定了SA系统
中互操作性和兼容性的定义。另外，OMG的SBC-DTF在2006 年12月为基于OMG的
SWRadio规范的SA接口规范提出了一个征求方案。最终，SA的API 规范由SAWG在2007
年末出版，并且支持OMG，SDR论坛提交了此API，以作为对OMG的 SA征求方案的回
应。
从根本上来说，SA的API规范为SA特有的信号处理像SA算法的 实现，信号同步的
增强和天线阵列的校准定义了软件组件和标准的应用接口。这些组件称为SA组件，是 将非
SA系统升级到SA系统的代理组件。对于SDR的标准SA系统来说，定义SA组件和API是最基本的也是必须的。
在本文中我们首次提出了智能天线系统的概念。我们也描述了SA系统的 标准和他的效
用、有点和好处。我们将对标准SA系统模块的详细说明作为入门。最后，我们以当前SA
系统的标准过程的状况来结束此文。
SA系统概述
SA系统是一个天线阵列系统， 增强了信号处理子系统，提高了无线系统的性能。如图
1所示，SA系统可以分为如下5个子系统。
1 一个天线阵列由多个具有特定形状的调配距离在SA系统类型的变化范围之内的天线
元素组成。
2 无线中频(RFIF)子系统配备了多个RFIF链。一般，每个RFIF链有一个低噪声放大器，混频器，模拟信号过滤器和一个模数转换器组成。
3 调制解调器子系统的基带信号处理如解调，交织解调和信道编码／解码。
4 SA子系统由算法组件－ 执行一个阵列的基带信号；一个校准组件，为多RFIF链之
间的校准；和一个为初始化移动终端增大目 标覆盖范围的增强型框架和信号同步的同步组
件。
5 MAC层子系统提供了一个地址访问通道，允许多个移动终端同时访问网络。
在图1中，通过用单天线 代替天线阵列，并且移除SA子系统的情况下，一般的SA系
统可以转换为传统的单天线系统。另外，传 统的系统可以通过运用天线阵列和SA子系统升
级到SA系统。这很引人注目以至于SAWG的SA标准 正源于此。
根据信号处理的方法，SA系统可以被分为以下四种：
波束形成系统：这些类型 的系统可以使天线聚焦到它的束模式来从特定的路径接收和传
输。合适的束形成系统通过高信噪比和低信 道干扰增强了通信能力。束模式的方向性增强了
传输效率，从而扩大了单元的覆盖范围。
分集 组合系统：这种类型的系统通过从空间隔离的组合天线的组合信号的接收，缓和了
多径衰落。
空间－时间均衡系统：在无线通信中，多径衰落给频率信号的接收引入了失真。如果将
时间处理加入到空 间分布的符合天线的信号中，频率选择的衰落就可以被消除。
多输入多输出系统(MIMO)：如果组 合天线元素的空间分布较远，独立的衰落信道，作
为并联平行的空间信道，在每个发射接收的天线组合间 被创建。多路独立的信息流通过空间
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信道，对于固定信号带宽和信道容量 ，数据传输速率随着发射和接收天线而线性增长。这种
类型的系统被当作特殊的多路系统。反过来说，时 空编码系统，另一种类型的多输入多输出
系统，使用复合发射天线来获得发射分集。
在特定的 通信环境下，每种SA系统都展现出各自的特性。例如，波束形成系统在强干
扰的通信环境中可以获得最 大的性能；而多输入多输出系统在无干扰的独立信道中可获得最
大的信道容量.
SA系统标准化的研究
为了使SDR系统利用SA系统的优势，基于SCA的开放体系应该首 先被确定。开放体
系结构的目标是通过将第三方跨平台软件生产商引入到系统中来，从而使整体的软件开 发变
得容易。为达到这一目标，结构应该分层，并且每层的职责要尽量清晰。另外，每层要为服
务提供标准的API。
硬件层包含了物理硬件设备如通用处理器，数字信号处理器，可重构的RFIF 设备和天
线阵列。硬件层上的OE层为SWRadio中的无线电系统管理提供了服务。SWRadio 设备层，
为信号处理、SA技术、网络访问和应用程序开发者的无线信道管理提供了服务。处在结构最上层的应用层由底层的负责完成端到端波形处理的波形应用程序、能够管理和控制无线电
机组的能 绘制独立波形的管理应用程序和其他的应用程序，如终端用户应用和支持路由选
择、安全和品质服务功能 的网络应用。
具体来说，SDR论坛的SAWG通过扩展和利用SA子系统的可复用性和互操作性定义
了SA组件。对于一个新的商业性市场，入口层组件基于操纵制造业的规模经济。而且，通
过S A架构图2所示，制造商可以确保一个共同的平台开发运作各种波形的SA系统。这两
个影响制造商提供 了创新的降低开发成本并加快产品上市时间的SA系统。此外，服务提供
商可以建立一个灵活的具有SA 系统提议的可伸缩的网络。确实，服务提供商通过将SA子
系统堵成非SA系统能够使SA系统适用于他 们的网络。此外，一项新的服务不能够强制服
务提供商建立一个新的网络。他们可以很容易地通过为新的 服务增加或更换软件组件来轻易
地提供新的服务。因此，在SAWG的组件是将成本效益引入到先进的无 线通信产业的入口。
SA子系统的建模中，SAWG沿用了MDA的解决方案。MDA的主要目标是便 携性、
互操作性和可复用性。当然，这是适用于建筑模型和在不同的平台执行这些模式[ 13 ] 。 为
了实现这些目标，一个模式的子系统（其中必须不包含任何信息具体化的平台或用于实现它
技 术）首先被定义。该模型称为组播（PIM）。在组播的定义中使用了UML（它定义了PIM
的元件的 属性）。在SA系统的PIM定义中，对于SWRadio组件和SA组件之间的互操作性，
SAWG选 择对SWRadio组件和他的扩展使用UML的侧面。一旦PIM完成，各种功能所定
义的PIM就可 以转化为模型与特定的信息平台形式。这种模式被称为平台相关模型（PSM）。
SA子系统的平台无关模型
如前所述，要将传统的SWRadio系统升级到SA系统，SA 子系统应包括校准组件，信
号帧同步组件，和一个算法组件。此外，在SAWG定义了控制组件，提供共 同的接口控制
其它组件捕捉SA子系统的状态。因此，SA子系统的PIM由同步设施，算法设施和控制 设
施三个群体的设计组成。同步设施由一个校准组件和同步组件组成。该算法的设施包括：算
法 部分执行了SA算法。控制设施，包括三个控制接口：是射频控制，算法控制和同步控制。
射频控制接口 用于控制多个RFIF器件和天线阵列。图-3说明了UML类图的SA子系统的
PIM。
同步设施-的同步设施包括校准组件，它实现了校准接口。同步组件实现了同步接口。
SA同 步是一个抽象的组件。校准组件和同步组件和专门的同步组件。同步组件为每个
信号的传输提供了至少一 个数据端口。
校准接口和校准组件用于校准多个射频链。校准接口补偿了射频中频链的每一天线传
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输和接收模式中幅度和相位差异。由于振幅和阶段特征的信号路径与每个天线各有不同，校< br>准会出现一些问题。尤其是当最优权重向量的从收到信号这种信号的上行通信SA系统计算
可充分 利用增强通信能力和单元覆盖范围。下行波束形成永远不能优化没有准确的校准。换
句话说，目标校准以 补偿相互之间的耦合效应天线阵列元素，以及不匹配的渠道振幅和或
通道阶段的SA系统。
同 步接口和同步组件用于符号或帧同步的SA系统。符号（或帧）同步检测符号（或帧）
的时机。在符号解 调（或帧解码）和运行SA算法之前完成同步。为了提高SA系统的性能，
必须提供准确的符号（或帧） 。此外，为了保证初始网络接入的服务质量，必须给SA系统
提供快速，强大的初始接入信号。
算法设施-该算法设施，其中包括算法组件（波形成组件 ，STC组件，空间多路组件，
信道估测 组件， DOA估测组件）和接口（波形成，空间时间译码， 空间多路技术，信道
估测技术和DOA估测技术）为所有的SA技术提供了服务，如波形成，多样化组合 ，到达
方向的估测，空间时间译码，空间多路技术和信道评价矢量。
SA算法是一个从所有算 法组件继承来的抽象组件。更具体地说，SA算法为所有的算
法组件提供共同属性和行为。波形成组件扩 展了SA算法，实现了波束形成接口，以便执行
波束形成算法。

原文：
Evolution and Standardization of the Smart Antenna System for Software Defined Radio

ABSTRACT
Transitioning proprietary or legacy softwaredefined radio networks to open
architectures,while often complicated, is increasingly critical to improve the interoperability and
compatibilityamong SDR networks and the subsystems within those networks as well. With this in
mind, two consortia, the SDR Forum and the Object Man-agement Group, have teamed to define
an open Smart Antenna specification. This specification defines a model (including an API) that
simpli- fies 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.
INTRODUCTION
Since the early 1980s, the wireless industry has rapidly grown through the development of
multiple standards and technologies. Each wireless standard has evolved with its specialized
service
such as voice, video streaming, wireless Internet access, or email service. This rapid expansion
compels customers (developers and end users) to use multiple devices for their various needs and
reduces the life cycle of the devices. Customers prefer to use a single device for multiple services.
On behalf of end-user requirements, manufacturers need to find a development technology that
supports flexibility, portability, reusability, interoperability, and cost efficiency of their
manufactured goods. The wireless industry (including the commercial, manufacturing, and
defense domains) faces change in development due to changes in capabilities demands, standards,
and tools supporting those standards. Software defined radio (SDR) enables a common radio
platform to support multiple standards and services by supporting dynamic software updates
(auto-download or other update methods preferred by various customers) and providing a
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framework for such change [1,2].
SDR solutions are varied, and in this article we address two related approaches to
standardizing the software-based common radio platform, a solid basis for the standardization of
software interfaces for the Smart Antenna (SA):
? The Software Communications Architecture(SCA) developed by the Joint Tactical Radio
System (JTRS) Joint Program Executive Office (JPEO).
? The Platform Independent Model (PIM) and Platform Specific Model (PSM) for Software
Radio Components [4] (a.k.a. The Universal Modeling Language [UML?] Profile for
Software Radio, or simply SWRadio) developed by the Object Management Group(OMG),
and based on the SCA coupled with the OMG’s Model Driven Architecture(MDA) as
described below.
First, as for the SCA, the mission of the JTRS JPEO is to develop a family of interoperable
and affordable SDRs at moderate risk, and provide secure and wireless networking
communications
capabilities for joint forces. Furthermore, the purpose of the SCA is to increase the portability of
waveforms from one JTRS radio to another [3].It establishes an implementation-independent
framework with baseline requirements for the development of software components for SDR. The
software components that provide for the management and execution of the SCA applications and
devices constitute the operating environment (OE) defined in the SCA. The OE consists of a core
framework (CF), common object request broker architecture (CORBA?) object request broker
(ORB), and Portable Operating System Interface (POSIX)-based operating system (OS). As
defined in the SCA specification, the CF is the essential set of open application-layer CORBA
interfaces and services that provide an abstraction of the underlying system software and hardware.
The CORBA ORB is common middleware that enables heterogeneous systems to perform
distributed processing with distributed system resources.
Second, the SWRadio specification was developed by the Software Based Communication
Domain Task Force (SBC-DTF) of the OMG,with early support and funding from the JTRS JPO
and ongoing participation from various defense, commercial, and academia partners. The
SWRadio specification enhances portability andreusability of waveform components as specified
in the SCA by defining a PIM and PSM for software components, including standard
applicationprogramming interfaces (APIs), for the physicallayer, link layer control (LLC),
medium accesscontrol (MAC) layer, and radio management based on the OE as defined by the
SCA. The PIMand PSM are fundamental concepts of the OMG’s MDA. The MDA is a
methodology for decoupling an SDR’s software model from the platform-specific deployment
technology (i.e., developmentlanguage, middleware, operating system, processor type, etc.). The
SWRadio specification contains a specialization of the UML (called a UML Profile) that is unique
for SDR technology. This SWRadio specification is the detailed specification tool vendors must
follow for providing applications to the SDR community. The SDR community uses these tools
for the modeling and implementation of their SDR and waveform applications, and the underlying
SWRadio components of which the applications are composed. The value of the toolmodeling
approach using MDA is in the reuse,portability, and interoperability of the resulting applications,
with the objective of reducing costand schedule to produce high-quality stable SDR deliverables.
In the end, the MDA capability of the SWRadio specification positions it as a highly
accommodating foundation for radio devices and services such as the SA technologies.
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However, neither the SCA nor the SWRadio specification currently supports SA
technologies,an essential element in advanced wireless systems. As members of the SDR Forum
recognized the importance of the SA in advanced wireless systems, the Smart Antenna Working
Group (SAWG) was formed under the technical committee of the SDR Forum. The charter of this
working group specifies the definition of a standard API for interoperability and compatibility of
the SA system [5]. Additionally, the OMG’s SBC-DTF issued a request for proposals(RFP) in
December 2006 soliciting proposals for an SA interface specification based on the OMG’s
SWRadio specification. Finally, the SA API specification [6] was published by the SAWG at the
end of 2007, and supporting the OMG process, the SDR Forum submitted this API as a response
to the OMG’s SA RFP.
Fundamentally, the SA API specification defines software components and standard APIs for
SA-specific signal processing such as performing SA algorithms, enhancing the symbol
synchronization and calibration of the antenna array. These components, called SA components,
are mandatory components to upgrade a non-SA system to a well defined SA system. Defining the
SA components and APIs is basic and necessary for the standardization of the SA system for SDR.
In this article we first provide an overview of what a smart antenna system is. We then
describe the standardization of the SA system and its effects, advantages, and benefits. We
elaborate on modeling of the standard SA system as a result of our approach. Finally, we conclude
this article with the current status of the standardization process for the SA.

OVERVIEW OF THE SA SYSTEM
The SA system is an antenna array system that enhances the signal processing subsystem to
improve the performance of wireless systems. As shown in Fig. 1, the SA system can be broken
down into five subsystems as follows:
? An antenna array consists of multiple antenna elements with a specific geometry where the
?
deployment distance between the elements varies with the type of SA system.
The radiointermediate frequency (RFIF)subsystem supplies multiple RFIF chains. In
general, each RFIF chain consists of a low noise amplifier, mixers, analog filter, and an
analog to digital (AD)digital to analog (DA) converter.
The modem subsystem performs baseband signal processing such as
de)modulation,(de)interleaving, and channel encoding decoding.
The SA subsystem consists of an algorithm component, which executes an array algorithm
with an array baseband signal; a calibration component, which compensates for
characteristics between multiple RFIF chains; and a synchronization component, which
enhances frame or symbol synchronization for enlarging coverage to acquire the initial access
of a mobile terminal.
? The MAC layer subsystem provides a channel access mechanism and addressing to allow
multiple mobile terminals to access a network simultaneously.

Based on the signal processing technique, the SA system can be categorized into four types:
Beamforming systems: These types of systems allow the antenna to adaptively focus its beam
pattern to receive and transmit from specific directions. Adaptive beamforming enhances
communication capacity through providing high signal-to-noise gain and low co-channel
interference to the desired user. In addition, the directivity of the beam pattern enhances
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transmission efficiency, and thus cell coverage is enlarged [7].Diversity combining systems: These
types of systems mitigate the effects of multipath fading through combining signals received from
spatially separated multiple antennas [8].
Space-time equalization systems: In wireless communications, multipath fading introduces
distortion to the received signal across the frequency. If temporal processing is applied to each
received signal from spatially distributed multiple antennas, the effects of the frequency selective
fading can be removed. [9]
Multiple-input multiple-output (MIMO) systems: If the multiple antenna elements are
deployed spatially far enough from each other,independent fading channels, referred to asmultiple
parallel spatial channels, are created between each transmit-receive antenna pair. Multiplexing
independent information streamsthrough the spatial channels allows data rates for a fixed
signaling bandwidth and channel capacity to be increased linearly with a minimum of transmit and
receive antennas. These types of systems are referred to as spatial multiplexing systems.
Conversely, space-time coded systems, another type of MIMO system, use multiple transmit
antennas to obtain transmit diversity. [10].
Each SA system can exhibit different performance characteristics in accordance with a given
communication environment. For example, beamforming systems obtain maximum performance
efficiency in the communication environment with existing strong interference while the MIMO
systems provide maximum channel capacity in a spatially independent channel without
interference.

AN APPROACH TO STANDARDIZING THE SA SYSTEM
In order for the SDR system to utilize the advantages of the SA system, an SCA-based open
architecture should first be defined [1]. The go of the open architecture is to easily integrate
software developed by a third party or non- platform manufacturer into the system. To achieve this
goal, the architecture should be layered and the responsibilities of each layer clearly defined. In
addition, standard APIs support the service(s)provided by each layer [11].
Figure 2 combines the SCA-based SWRadio open architecture [4] of the OMG’s SBC-DTF
with the antenna array and SA facilities defined by SDR Forum’s SAWG. The hardware layer
includes physical hardware devices such as a general- purpose processor (GPP), a digital signal
processor (DSP), a field-programmable gate array (FPGA), a reconfigurable RFIF device, and an
antenna array. The OE layer on the hardware layer provides services for radio system management
defined in SWRadio. The SWRadio facilities layer offers services for signal processing, SA
technologies, network access, and radio channel management to application developers. The
application layer at the top of the architecture consists of waveform applications that leverage the
lower layers to achieve full end-to-end waveform processing, management applications that figure
waveform independent applications to enable management and control of the radio set, and other
applications such as end-user applications and network applications, which support routing,
security, or quality of service (QoS) functions.
The SA architecture in Fig. 2 illustrates the SA system with the definition of SA components
that enable a non-SA system to be converted to an SA system. Specifically, the SAWG of the SDR
Forum defines the SA components by extending and leveraging SWRadio components for
portability and interoperability of an SA subsystem. This component approach lays the
groundwork for a new commercial off-the-shelf(COTS) market for SA subsystems by driving
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economies of scale in manufacturing. Moreover, through the SA architecture shown in Fig. 2, the
manufacturers can secure a common platform for developing SA systems that operate in various
waveforms. These two effects provide manufacturers an innovatively reduced development cost
and accelerated time to market [12] for SA systems. Also, service providers can build a flexible
network with the proposed SA system. Indeed, the service providers are able to apply SA
technologies to their network by just plugging the SA subsystem into their non-SA system. In
addition, a new service does not force service providers to build a new network. They can easily
provide new services by adding or replacing software components for the new services.
Consequently, the SAWG’s component approach introduces cost efficiency to the advanced
wireless industry. MODELING THE

STANDARD SA SUBSYSTEM
In modeling the standard SA subsystem, the SAWG followed the MDA approach. The
primary goals of MDA are portability, interoperability, and reusability. This, of course, is applied
to architectural models and the implementation of those models across different platforms [13]. In
order to achieve these goals, a model of the subsystem (which must not contain any information
specific to the platform or the technology used to realize it) is defined first. This model isreferred
to as the PIM. In defining a PIM, UML(which defines the properties of the PIM’s elements) is
used. For the interoperability between SWRadio components and SA components, the SAWG
chose to use the UML Profile for SWRadio components and its extensions in defining the PIM for
SA components. Once the PIM is complete, the various functionalities defined by the PIM can
then be transformed to a model with information specific to the platform. This model is referred to
as the PSM.
In the following subsections the PIM and PSM for the SA subsystem are described in more
detail.

PLATFORM INDEPENDENT MODEL FOR THE SA SUBSYSTEM
As mentioned previously, to upgrade a conventional SWRadio system to an SA system, the
SA subsystem should include a calibration component, a symbolframe synchronization
component, and an algorithm component. Additionally, the SAWG defined a control component to
provide common interfaces for controlling other components and to capture the state of the SA
subsystem. Therefore, the PIM for the SA subsystem consists of three groups of facilities:
synchronization facilities, algorithm facilities, and control facilities. The synchronization facilities
have a calibration component and a synchronization component. The algorithm facilities include
algorithm components to execute the SA algorithms. The control facilities consists of three control
interfaces: are RF Control, Algorithm Control, and Synchronization Control. The RF Control
interface is used to control multiple RFIF components and the antenna array. Figure 3 illustrates
the UML class diagram of the PIM for the SA subsystem. Synchronization Facilities — The
synchronization facilities include the Calibration Component, which realizes the calibration
interface; the Synchronization Component realizes the synchronization interface.
SA Synchronization is an abstract component. Calibration Component and Synchronization
Component specialize the SA Synchronization. SA Synchronization provides at least one data port
for each signal transfer.
The calibration interface and Calibration Component are used for calibration of multiple RF
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chains. The calibration interface compensates for amplitude and phase differences of the RFIF
chain associated with each antenna in transmit and receive mode. Calibration problems have
arisen because the amplitude and phase characteristics of the signal path associated with each
antenna are different from each other. This is especially true if the optimal weight vector is
computed from the received signal such that the uplink communication of the SA system can fully
utilize the enhancements in communication capacity and cell coverage. Downlink beamforming
can never be optimized without accurate calibration. In other words, the objective of calibration is
to compensate for the mutual coupling effects between antenna array elements as well as the
mismatches of channel amplitude andor channel phase in SA systems.
The synchronization interface and Synchronization Component are used for symbols or
frame synchronization of the SA system. Symbol(or frame) synchronization is used to detect
symbol (or frame) timing. Synchronization is performed prior to symbol demodulation (or
decoding of frame) and running the SA algorithm. To enhance the performance of an SA system,
accurate symbol (or frame) timing must be provided. In addition, to guarantee the QoS of the
initial network access, fast and robust acquisition of initial access signal must be provided to the
SA system. Algorithm Facilities — The algorithm facilities, which consist of algorithm
components (Beam-forming Component, STC Component, Spatial Multiplexing Component,
Channel Estimation Component, and DOAE stimation Component) and interfaces (Beam forming,
Space Time Coding, Spatial Multiplexing, Channel Estimation, and DOAE stimation), provide
services for all types of SA technologies such as beam forming, diversity combining,
direction-of-arrival (DOA) estimation, space-time coding, spatial multiplexing, and vector channel
estimation.
The SAAlgorithm is an abstract component from which all algorithm components inherit.
More specifically, the SAAlgorithm provides common attributes and operations for all algorithm
components. The Beam forming Component extends the SAAlgorithm and realizes the beam
forming interface in order to execute the beam forming algorithm.
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