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Software Communications Architecture and Related Specifications Overview

Kevin Richardson

09 April 2006

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• Definition of Software Architecture:A software architecture is characterized by a particular combination of software

components and connections.

The SCA provides a framework, not functionality.

• The JTRS Software Communications Architecture(SCA) Enables:– porting of “waveforms”

– reuse of software (largely internal to development organization)

– extensibility of hardware and software (emphasis on modeling)

– interoperability between platforms

– use of commercial product lines (as it gains commercial acceptance)

What is An Architecture?It is an Enabler

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– Independent ofwaveform functionality

– “Component oriented” – profiles describe HW / SW components

– Defines SW Interfaces for data connection and management control

– Defines a common management framework

• to configure, connect and tear-down distributed applications

What is the SCA?What is the SCA?

• The JTRS SCA specifies an open, non-proprietary architectural framework

GPP

GPP GPP

DSP DSPFPGA

Devices

POSIX CORBA

RF

D

o

m

a

i

n

M

g

r

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How can the SCA Benefit DoD?

ADCRF

Analog

ToApplications

Recompilation

Recom

pila

tion

GPP

GPP

DSPFPGA

Devices

POSIX CORBA

R

FDomain

M

g

rGPP

GPP GPP

DSP DSPFPGA

Devices

POSIX CORBA

R

FD

o

m

a

i

n

M

g

r

“same” waveform software runs on different hardware sets

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Criteria for the SCA

– Based on Open, Commercial Standards• OMG, IEEE, IETF

– Supports a Family of Radios • Interoperable,

• Programmable

• Scaleable (handheld to fixed-station),

– Maximizes Platform Independence of Software from Hardware• Application and Device Portability & Reuse

• Rapid Technology Insertion Over Time

– Extendible to New Waveforms and/or Hardware Components

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Core Framework (CF)

Commercial Off-the-Shelf (COTS)

Applications

OperatingEnvironment (OE)

Red Hardware Bus

CFServices &

Applications

CORBA ORB &Services

(Middleware)

Network Stacks & Serial Interface Services

Board Support Package (Bus Layer)

Black Hardware Bus

CFServices &

Applications

CORBA ORB &Services

(Middleware)

Network Stacks & Serial Interface Services

Board Support Package (Bus Layer)

Operating System

Core Framework IDL

Non-CORBAModem

Components

Non-CORBASecurity

Components

Non-CORBA I/O

Components

RF

ModemComponents

Link, NetworkComponents

SecurityComponents

ModemAdapter

SecurityAdapter

SecurityAdapter

I/OAdapter

I/OComponents

MAC API LLC/Network API LLC/Network API

Link, NetworkComponents

Security API

Operating System

Physical API

I/O API

(“Logical Software Bus” via CORBA)

SCA Software Structure

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The SCA “Model”

• Software

– Operating Environment

• POSIX-based operating system (OS)

• CORBA / Interface Definition Language (IDL)

• JTRS Core Framework (CF)

• Domain Profile (XML-based)

• Hardware

– Classes (Operations and Interfaces)

• Rules for Implementation

– How the Architecture is applied to products

• The SCA does not …– specify implementation-level details– define all the elements or interfaces for a SDR– guarantee portability

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• The SCA CF is a “core” set of interfaces that provide an abstraction of the

underlying software and hardware layers for software application designers

• CF Interfaces (defined in IDL) consist of:

- Base Application Interfaces (Port, LifeCycle, TestableObject, PortSupplier, PropertySet,

ResourceFactory, and Resource) that can be used by all software applications

- Framework Control Interfaces (Application, ApplicationFactory, DomainManager, Device,

LoadableDevice, ExecutableDevice, AggregateDevice, and DeviceManager) that provide control of

the system

- Framework Service Interfaces (File, FileSystem, and FileManager) that provide interfaces for

distributed file access services to software application components

- Domain Profile that describes the properties of hardware devices and software components in the

system and enables application deployment

SCA Core Framework DefinitionSCA Core Framework Definition

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CORBA

CORBA-capable processor

Domain Manager

Device Manager

Each Device Manager responsible for booting its Devices and Services

HardwareDevices

HardwareDevices

HardwareDevices

DCD

All Dev Mgrs report toDom Mgr

DCD tells Dev Mgr what HW devices exist

1 Domain Mgr1 Device Mgr per CORBA-capable processor

• 1 Domain Mgr per JTR Set• 1 Device Mgr per CORBA Capable processor

• Device Mgr starts up its device (in parallel)• Primarily works at “power on”

Power activates: OS ORB Device Managers 1 Domain Manager

Platform MangementPlatform Mangement

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Domain Mgr Knows Devices,Applications, & Resources

• XML Profiles provide application Metadata• “resource” + Software Profile Descriptor = a “component”• “install” creates an Application Factory• An Application Factory starts up an Application instance

DomainManager

ApplicationFactory

DeviceManager

HMI

Res

ourc

es

Dev

ices

SADDCD

HardwareDevices

One Dev Mgr per CORBA-capable processor

HMI access uses Dom Mgr

An App Fac is created for each installapplication, i. e. SAD

SAD describes the components that comprise an application

DCD defines characteristics of devices to be loaded

ApplicationOn starting Application

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Resource

Collectionof

FunctionalityProgrammer-Defined

StartStop

ControlData

User-DefinedInterfaces

Get Port

Run TestInitializeRelease

• A resource “packages” together object code that runs within a processor • Provides set of “control” operations (primarily used by Core Framework)• Functionality and Interfaces (ports) are supplied by programmer

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Device

Collectionof

FunctionalityProgrammer-Defined

StartStop

ControlData

User-DefinedInterfaces

Get Port

Run TestInitializeRelease

State

LoadExecute

Aggregate

Hardware

• A Device IS a resource that provides a HW abstraction• State reflects state of the hardware: Usage, Admin, Operational

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Core Framework IDL RelationshipsCore Framework IDL Relationships

<<Interface>>

Device <<Interface>>

Application

<<Interface>>

DomainManager

inheritsfrom

uses

<<Interface>>

ApplicationFactory

<<Interface>>

DeviceManager

<<Interface>>

FileManager

deviceManagers

1..*

0..*

applicationFactories

fileMgr1

applications

0..*

uses

<<Interface>>

File

fileSys

0..1

<<Interface>>

Resource<<Interface>>

ResourceFactory

Core Framework Interface

Implemented byNon-Core Applications

Core Framework Interface

Implemented asCore Application Services

Legend

<<Interface>>FileSystem

<<Interface>>

LoadableDevice

<<Interface>>

ExecuteableDevice

<<Interface>>

AggregateDevice 0..*devices

<<Interface>>

PropertySet

<<Interface>>

PropertySet<<Interface>>

LifeCycle<<Interface>>

TestableObject<<Interface>>

PortSupplier<<Interface>>

Port

Base Application Interfaces

Framework Control Interfaces

Framework Services Interfaces

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SCA Base Application Interfaces

• Port– used to connect Resource Components

• LifeCycle– used to initialize or release Resources

• TestableObject– used to test a Resource

• Port Supplier– used to obtain a specific port

• PropertySet– provides operations to access Resource properties

• ResourceFactory– Used to create / tear down Resources

• Resource– provides common interface for Resource control and configuration

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SCA Framework Control Interfaces

• Application– CF provided container for Resources that make up application

• provides interfaces for control, configuration, status and tear-down

• ApplicationFactory– used to create application (waveform) instances

– based on Domain Profile• allocates SW (Resources) to HW (Devices) - allocates capacities

• connects Resources that make up application

• performs initial configuration

• DomainManager– Provides interface for DeviceManager, Device and Application registration

– Provides access to registered DeviceManagers, installed and Running applications, the platform’s FileManager

– Provides interface to HCI to access the domain and its capabilities (Devices and Applications)

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SCA Framework Control Interfaces (cont.)

• Device

– A software proxy for a physical hardware device

– Represents CF interface between applications and devices

– Typically one Device per HW device

– Loadable, Executable, and Aggregate Devices extend behavior of the

Device Class

• DeviceManager

– Manages a set of logical Devices and services

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SCA Framework Services Interfaces

• File

– Provides access to files within the radio

– Allows access across processor boundaries (distributed file systems)

• FileSystem

– Enable remote access to physical file systems

– Allows creation, deletion, copying, etc of files

• FileManager

– Manages multiple distributed FileSystems

– Looks like a FileSystem to client

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SCA Domain Profile

• A set of files that describe HW and SW components making up

an SCA system domain

• eXtensible Markup Language (XML) format

• Document Type Definitions (DTDs) describe the files

[Customized to better address Software Radio Needs]

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SCA Status

• SCA is being accepted by Industry– An “SCA equivalent” exists within the family of OMG Standards

– Commercial tool vendors and industry have provided some SCA tools• PrismTech, Zeligsoft and CRC

• The SCA has undergone three phases of architectural validation and provides the backbone for JTRS Cluster 1

• The SCA and its underlying technologies target a GPP based platform however many of the abstractions are applicable to other processing environments

• The JTRS program office has a plan in place to continue to evolve the SCA

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Software Communications Architecture

Note: All dates represent estimated OMG schedules

Finalization

April 05

Schedule for standardization of SCA related specifications at theObject Management Group (OMG)

Nov 04Jul 04

Formal spec

Adopted spec

Finalized spec

Sep 05

Formal

Standard

July 03

Lightweight Log ServicesSpecification Adoption

Nov 03

Lightweight Services

Feb 04

PIM and PSM for SW Radio

June 04

Lightweight CCM

Nov 03

Deployment & Configuration

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SWRadio MDA Principles

• UML Profile for SWRadio extends UML for SWRadio tool support: validation, system engineering, and SWRadio component development

• PIM has been primarily structured as a set of facilities each addressing a key aspect of SWRadio

• Well-defined set of modeling conventions– Naming conventions

– Modeling conventions

– Subset of UML notation

– Specific semantics of this notation in the context of this PIM

• Conforms to MDA– PIM can be transformed to different component platforms

• CORBA-PSM, Java-PSM, etc.

• Compatible with existing OMG standards– MOF

– UML

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SWRadio MDA Principles, cont’d

OMG UML

Meta ObjectFacility (MOF)

Meta-Model Layer (M2)

Meta-Meta-Model Layer (M3)

PIM & PSM Layer (M1)

Domain & PlatformTechnologyprofiles

«extends»

«instanceOf»

Waveform, Device,Radio Infrastructure &Service PSM Components & Artifacts (XML Descriptors, Executables)

«refine»

Runtime or Deployed Artifacts Layer (M0)

Waveform, Device, Radio Infrastructure& Service ComponentsPIMs

UML Profiles forSWRadio,CORBA, Java, C++, XML Schema

«instanceOf» «instanceOf»

Waveform, Device, Radio Infrastructure& Service ComponentsPSMs, CF Interfaces, XML Descriptors

«instanceOf»

Profiles M1 Data

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SWRadio Development Viewpoints

• To address the issues of the different actors involved in SWRadio product developments, the current profile was developed with three main viewpoints in mind: – the viewpoint of application and device developers,

– the viewpoint of infrastructure/middleware providers, and

– the viewpoint of SWRadio platforms providers.

• These three viewpoints define distinct sets of concepts (and stereotypes) that are required in different contexts.

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SWRadio Development Viewpoints, cont’d

Radio Control Facilities

(from Facilities PIM)

Infrastructure Providers

Application and Device Providers

Common Radio Facilities

(from Facilities PIM)

ApplicationApplicationResourceComponent

*1..*

+componentAssembly

*

+appComponent

1..*

DeviceComponent

**

**

DeviceDriver

1..*

*

+logicalDevice1..*

+deviceDriver *

RadioSystem

LogicalCommunicationChannel

1..*1..*

CommEquipment

1..*

1

+deviceDriver

1..*

+commEquipment

1

RadioSet

1

1..*

1

1..*

1..*1..*

Data Link Layer Facilities

(from Facilities PIM)

Common Layer Facilities

(from Facilities PIM)

Physical Layer Facilities

(from Facilities PIM)

Application Deployment

(from SWRadio Deployment)

Radio Services Element Definitions

Radio Management

SWRadio Platform Providers

PIM Facility

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UML Profile for SWRadio

• To be consistent with the three development viewpoints, the UML Profile for SWRadio is partitioned in three main packages:

– the Applications and Devices Components, – the Infrastructure, and – the Communication Equipment package.

• Each package defines the set of concepts and UML stereotypes required to perform a specific role in the development of an SWRadio product.

Application and Device Components

Communication Equipment

Infrastructure

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UML Profile for SWRadio Application & Device Components

• Application Components– Contains the component stereotypes for application developers– Application, ApplicationResourceComponent, LayerResource (Data Link, MAC,

Physical)

• Base Types– Contains the common types for defining SWRadio components.

• Interface & Port Types– Contains the port and interface stereotypes for SWRadio interfaces and components

• Device Components– Contains the component stereotypes for device developers– Logical Device, Loadable and Executable

• Properties– Contains property stereotypes for SWRadio components– Configure, Query, Characteristic, Capacity

• Resource Components– Contains the interface and component stereotypes for waveform and device

developers– ControllableComponent, LifeCycle, PropertySet, ResourceComponent, etc.

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UML Profile for SWRadio Resource Components

LifeCycle<<interface>>

PropertySet<<interface>>

TestableObject<<interface>>PortSupplier

<<interface>>

ControllableComponent<<interface>>

SWRadioComponent<<stereotype>>

PortConnector<<interface>>

ResourceComponent<<stereotype>>

SWRAPI<<stereotype>>

*

*

*

*<<swapiRealization>>

*

*

*

*

<<swapiUsage>>

ComponentIdentifier<<interface>>

Resource<<stereotype>>

ResourceFactory<<stereotype>>

*

0..1

+product*

+creator

0..1

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UML Profile for SWRadio Infrastructure

• Radio Services– Common services within the radio platform that are utilized by

applications

– Managed component service

• Radio Management– RadioSet, RadioSystem, and Device Management

• Communication Channel– Physical, IO, Security, and Processing Channel

– Captures the relationships between channels and SWRadio devices

• Application Deployment– Components and Artifacts stereotypes for the deployment of:

• Waveforms on communication channel’s distributed devices

• Radio Services within the Radio Set

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UML Profile for SWRadio Infrastructure, cont’d

RadioSystem(from Communication Channel)

RadioSet(from Communication Channel)

RadioSystemManager<<stereotype>>

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+radioSystem

1

+radioSystemManager

1

LogicalCommunicationChannel(from Communication Channel)

<<stereotype>>

RadioManager<<stereotype>>

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+radioSet

1

+radioManager

1

0..1

1..*

+radioSystemManager

0..1

+radioManager1..*

ApplicationFactory(from Application Deployment)

<<stereotype>>ApplicationManager(from Application Deployment)

<<stereotype>>

CommChannel<<stereotype>>

1 1

+commChannel

1

+logicalCommChannel

1

1..*1..*

*

1..*

+waveformDeployer

*

1..*0..1

1+deployedWaveform

0..1

1

DomainManager<<stereotype>>

Service<<stereotype>>

DeviceManager<<stereotype>>

1..*

1

+deviceManagrRegistrant 1..*

+domainRegistrar

1

+registeredService

1..*1..*

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UML Profile for SWRadio Communication Equipment

• Stereotypes for SWRadio devices

• Communication Equipment describes the relationships and attributes that are appropriate for radio devices.– Crypto Device - performs encryption and decryption on asset of data.

– I/O Device - describes the relationships and attributes that are appropriate for I/O devices

• Antenna, Amplifier, Filter, Frequency Converter, audio, serial, etc.

– Power Supply - provides electrical power to other devices.

– Processor Device - processes digital or analog data.

• Port Types– Analog & Digital

• Property Types– Characteristic & Configure

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UML Profile for SWRadio Communication Equipment, cont’d

IODevice<<stereotype>>

PowerSupply<<stereotype>>

Processor<<stereotype>>

CryptoDevice<<stereotype>>

RequiredTypes<<modelLibrary>>

+ AmplitudePhaseResponse+ AntennaCalibration

+ AntennaType...

AnalogInputPort<<stereotype>>

AnalogOutputPort<<stereotype>>

DigitalPort<<stereotype>>

CommEquipment

<<characteristicproperty>> equipmentSize : Size<<characteristicproperty>> equipmentWeight : Weight<<characteristicproperty>> maintenancePeriod : Time [0..1]<<characteristicproperty>> maxOperatingTemperature : Temperature<<characteristicproperty>> meanTimeBetweenFailures : Time [0..1]<<characteristicproperty>> minOperatingTemperature : Temperature<<characteristicproperty>> powerConsumption : Power<<characteristicproperty>> radiationCapability : Radiation [0..1]<<configureproperty>> lastMaintenanceCheck : Date [0..1]<<queryproperty>> equipmentInformation : PlugAndPlayInformation<<queryproperty>> temperatureStatus : Temperature [0..1]

<<stereotype>>

1

*

+device

1 +analogReceiverPort

*

1 *

+device

1

+analogTransmitterPort

*

+digitalPort

+device

1

*

1

*

Device(from UML)

<<metaclass>>

<<extension>>

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SWRadio PIM Facilities

• Common Radio Facilities– Provides common service definitions that are applicable for all

applications (waveforms or radio control)

– File Services, OMG Lightweight Services (log, event, naming, etc.)

• Common Layer Facilities– Provides interfaces that cross cut through facilities that correlate to

layers. These interfaces can be viewed as building blocks for SWRadio components that realize multiple interfaces.

– Protocol Data Unit, Error Control, Flow Control, Measurement, Quality of Service, and Stream Facilities

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SWRadio PIM Facilities, cont’d

• Data Link Facilities– Link Layer Control (LLC) facilities. LLC layer provides facilities

to upper layers, for management of communication links between two or more radio sets.

– Data Link Layer (Connectionless, ConnectionLess Ack, Connection), and Medium Access Control Facilities

• I/O Facilities– Defines the configuration properties for Audio and Serial Facilities

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SWRadio PIM Facilities, cont’d

• Physical Layer Facilities– Modem Facilities

• The modem facilities include all digital signal processing elements required to convert bits into symbols and vice versa.

– RF/IF Facilities• The RF/IF Facilities is used to configure and control the basic devices

of the physical channel. The granularity at which these interfaces are implemented is not specified.

• Radio Control Facilities– Provides for interfaces for radio and channel management.

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SWRadio PSM

• Automatic PSM generation from PIM and profile definitions– Transformation rule set specified in the specification

• Platform Specific Model– CORBA Modules

• CF– StandardEvent, PortTypes

• DfSWRadio– CommonLayer, DataLinkLayer, CommonRadio, PhysicalLayer, RadioControl

• DSFileServices

– XML Schema• Properties• Communication Channel• Physical Layer Properties

– POSIX

• Other PSMs could be defined

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SWRadio Lessons Learned

• Benefits– Promotes separation of design / development concerns

• Nothing new (good SW Engineering principles)

– MDA approach requires more formal/complete models• Enables artifact generation

• Impediments to adoption– Lack of tools (transformation, generation, UML extension, MOF

infrastructure)

– Programmatic conflicts exist regarding integrating new specs into an existing product family

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Summary

• The SCA provides a platform and development language independent architectural framework upon which SDR (and other distributed, component based) applications can be built.

• The underlying platform independent SCA model has been emphasized in areas such as the OMG family of specifications

• The SCA “works” however there are areas for evolution– Resource Constrained processing environments

– Extendiblity into other platform specific middlewares and OEs