definition of embedded software using the waveform description language,

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Racal Research

A Thomson-CSF Racal Company

Definition of Embedded Software using the Waveform Description Language,

E.D.Willink, Racal Research Limited,[email protected],

Software Defined Radio Forum,12th September 2000,

UK Programmable Digital Radio (PDR) Phase 1,

Waveform Description Language (WDL) programme

(DERA contract CU009-0000002745)

Raytheon, Communication Systems Division, Fort Wayne, Indiana,

Racal, Racal Research Limited, England

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Introduction

• Specifications• Examples• Architectural Mapping (JTRS)• Summary

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The SDRF Software Architecture

Installer

CFServicesLogger

Timer

DomainManager

FileManager

ResourceManager

Factory

Access

Link

registerswith 1..*

oversees1

accessesSWfiles via

1

knows whatSWis availablevia

1..*

loads core&non-core1..*

detects &reports

1

1

creates1..*

1

requestsresources

of1..*

ModemAdapter

provides

LifeCycle

MessageRegistration

Message

aretypes

guides start-up&teardownvia

sets up virtualpathdestinations

via1..*

File stores &retrieves

0..*

basesallowableconfigurations

on 1..*

aretypesof

Executable SW

DomainProfile

1

1 1

Modem Network

UtilityRF

HostAdapter

AudioSerialEthernet

GPSModem

GPLRF KeyFill

Crypto

SecurityAdapter

Security

application

decryptsCTfor1..*

sendsPT to

1

decryptsPT for 1..*

1 sendsCT to

1..*

controlsradiovia

1

acts onC2 for

Bridge Router

1..*

routesto/from1..*

bridgesto/from 1..*

translatesprotocols

for 1

11

1translatesprotocols

for

1..* interceptsCTto/from

1

111

1implementsModem API

for

1 1

RFAPI

analog

1..*

acts onBB / IF/complex

for1..*

1acts onA/D,D/A for

1implementsInfosec API

for

1interceptsPT

to/from

SignalGen./Antenna

of radio

Resource

FileSystem

0..*

1..*

1

resources

1..*1..*

HWDevice

providesservices

for1

1..*

Waveformprovidesservices

for

providesaccessto

1 1 1

1

1

1..*

1..*

1

Gateway

Repeater

retransmitssignalsof

1

1

StateManagement

1..*loads&unloads

providesservicesfor

0..*

1

1..* sets/getsResource

statesvia

1

1

Core Framework(CF)Commercial Off-the-Shelf

(COTS)

Non-Core (Radio)Applications

OE

http://www.sdrforum.org/MTGS/mtg_19_jun00/tech_comm_seattle.ppt slide 20

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Contrasting/Complementary approach

• Implementation– How it can be done

• Specification– What needs to be done

Waveform Definition Language (WDL)– one specification– many alternate implementations

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Specification of Systems and Subsystems

• subsystems exist at many scales– international/national/regional/local/internal phone network– cabinet/rack/module/board/component equipment

• CORBA components support two scales– inside– outside

• WDL– same approach for many scales– specify without implementing– refine specification into an implementation

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Specification of Communication

• High level systems– sporadic control events

• Low level systems– intensive calculation– ‘continuous’ communication

• WDL– sporadic and continuous flows are supported– continuous and discrete time are interchangeable

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Complete specification (Low Level)

• Amplifier relatively easy– vout = 10 * vin

• In practice need constraints– frequency < 1 GHz– load impedance 50Ω ± 10%– third harmonic ...

• WDL– mathematical definition of the ideal behaviour– constraints to bound permitted behaviour

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Complete specification (High Level)• System specifications

– large, unreadable

• Informal specification– omissions lead to ambiguities– duplications lead to contradictions

• Formal specification– good in principle – impractical for real applications– unapproachable for most practitioners

• WDL– pragmatic compromise

* formalisable, modular, familiar, practical, acceptable

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Specification in WDL• Progressive decomposition

– systems - subsystems - components - building blocks

• Single hierarchical perspective– clear readable specification– removes ambiguities, avoids contradictions

Implementation in WDL• Progressive refinement

– further decomposition– practical constraints– recomposition

• Minimal refinement– executable reference model

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WDL Transformations

W D LC om pile rs

S chem aticE d ito rs

D ecom position

R efinem entText

E d ito rs R efiner

C hecker

W D L P roducts, W aveform B und le

W D L P rogram

W D L S pecifica tion

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WDLRefinement

W D L P rogram

S ponsor

A bstract S pecifica tionlayerscodersm odula tors

Im plem enter

A ctua l S pecifica tiona lgorithm sparam etersb it-tru th

R eference M ode lprecis ionsacqu is ition a lgorithm s

S ystem D esignfilte r characteris ticsacqu is ition a lgorithm sm in im um precis ions

S ystem C onfigura tionfilte r characteris ticsdecim ation ra tios

H ardware M appingpartition inglib rary m atch ing

C om ponent C onfigura tionparam eterisa tionactua l p recis ionsb it-tru thW D L S pecifica tion

R eference M ode l P roduct

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Refinement

• Abstract WDL specification (unimplementable)• Waveform sponsor refines to support

– a reference model

• System designers refine to support– hardware partitioning– analogue/digital partitioning– concrete filter designs– specific acquisition strategies– apportion implementation loss budgets

• Implementers refine to– exploit pre-existing object libraries– compensate for compiler limitations

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Hierarchical decomposition

• Entity– module of specified behaviour– not necessarily an implementation object

• Message– user defined data types (and array shapes)– four scheduling flow types

• Hierarchical Diagrams– message flow diagrams– statecharts

• Leaf specification– mathematical definition

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(UML) Statechart

StateChartEntityeventguard

out State1

State2

event[guard]/out(...)

WDL extension to UML:state behaviour may be a

message flow

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Message Flow Diagram

UML Collaboration diagramexternal scheduling, connection points have no semantics

WDL Message Flow Diagrameach arc has defined data and flow type, connecting at ports

each entity is self-scheduling - rendez-vous of relevant ports

external ports to define hierarchy

Entity2in outin1

outin2

Entity1in1in2

out

M essageFlowEntityin1in2

out

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FM3TR Protocol Layers

Hcinwk

d lc

m ac

ph l

vo ice_ in

data_ in

data_out

antennavo ice_out

M actx_ from _dlchcirx_ from _ph lcarrie r_detect

rx_ to_d lc

tx_ to_ph l

Phltxhci

vo ice_ in

rxcarrie r_detect

an tennavo ice_out

Dlcin_ from _nwkhcirx_ from _m ac

out_ to_nwk

tx_ to_m ac

Nwkdata_ inhciin_ from _dlc

data_out

out_ to_d lc

Fm 3trdata_ invo ice_ in

data_outvo ice_out

antenna

Application

Presentation

Session

Transport

Network

Data Link

Physical

OSI layers

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Hop Modulator

tuningtim e

risetim e

falltim e

inform ationtim e

HopM odulatorhopconfig

m odula tion

IN FO R M A T IO N

m odula tionconfighop

In foM odulatorconfighop

m odula tion

TU N IN G _T IM E


G uardM odulatorconfighop

m odula tion

R IS E _T IM E


RiseM odulatorconfighop

m odula tion

FA LL_T IM E


FallM odulatorconfighop

m odula tion

afte r(config .tun ing_tim e)

a fte r(config .rise_ tim e)

exit

a fte r(config .fa ll_ tim e)

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Hop Rise Time

RiseM odulatorconfighop

m odula tion

m odula tion

F(t)

am p

out

Constructoram plitudefrequency_sh iftfrequency

m odula tionConstant

sh ift

ou t

Constant

freq

out

constraint: amp.out = range{

minimum 0;value 0.5 * (1 - cos(2*pi*t/config.rise_time));

maximum 1;};

constraint: shift.out = 0;

constraint: freq.out = hop.frequency;

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Language for specification

• need expressions for– configuration constraints, state machine guards

• need statements for– state machine actions

• need types for– messages

need a language– implementation languages do not specify

– specification languages are unapproachable

– specification languages have unhelpful focus

– new language is new

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Specification

entity Subtractor{in minuend;in subtrahend;out difference;response minuend subtrahend{specification{difference(minuend - subtrahend);

};};

};

Polymorphic– type, shape, flow, language

Subtractorm inuendsubtrahend

d iffe rence

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Hardware Mapping

• Bespoke hardware– direct compilation

* one executable per processor

• ‘Virtual’ hardware - software radio– identify components and messages– indirect compilation

* one executable per component per platform

* one interface declaration per message

* configuration profiles per application

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FM3TR Layers

asJTRS

Componentsand

MessagesFm 3trH ci

Fm 3trM odem

Fm 3trL ink

Fm 3trN etworkHci

nwk

d lc

m ac

ph l

vo ice_ in

data_ in data_out

antenna

vo ice_out

M actx_ from _dlchcirx_ from _phlcarrie r_detect

rx_ to_d lc

tx_ to_ph l

Phltxhci

vo ice_ in

rxcarrie r_detect

antennavo ice_out

Dlcin_ from _nwkhcirx_ from _m ac

out_ to_nwk

tx_ to_m ac

Nwkdata_ inhciin_ from _dlc

data_out

out_ to_d lc

D outD in

D toM

N toD

V outV in

H toP

H toM

H toD

H toN

D toN

M toD

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JTRS Mapping

Board S upport P ackageN etwork P ro toco l S tacks

Posix R TO S D SP E xecutive

B lackIN FO S ECAdapter

R edIN FO S EC

Adapter

IN FO S EC A lgorithm


Posix R TO S

C ++ C O R B AO R B andServices

C F C oreD om ainM anagerD eviceM anager

F ile ServicesLoggerT im er

D evice

Board S upport P ackageD SP E xecutive

B lack cPC I R ed cPC I

M odem B lack C ontro l P rocessor R ed C ontro l P rocessorIN FO S EC


Posix R TO S

C ++ C O R B AO R B andServices

C F C oreD om ainM anagerD eviceM anager

F ile ServicesLoggerT im er

D evice

Fm 3trH ci

Fm 3trN etwork

Fm 3trM odem .P hl.T ranS ec Fm 3trL inkFm 3trM odem .M acFm 3trM odem .P hl.nonTranSec

Fm 3trM odem

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WDL & JTRS Summary

• JTRS – a common radio architecture for waveform development– modelled after very successful PC paradigm– allows third party development of low cost applications

• WDL– efficient methodology for developing many waveforms– provides unambiguous specification– provides portable implementation

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Summary

• WDL specifies a determinate behaviour• Decomposition to manageable sub-specifications

• Refinement to support a reference model• Refinement to support product implementations

• Polymorphism to exploit generic libraries• Realistic scheduling models• Type-oriented code generation for flexibility

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Status

• Phase 1– Initial consideration of language concepts– Example decomposition of FM3TR (1 month)

* clearer

* many anomalies reported back

• Future– Better quality specifications

* sponsor provides reference model

– Semi-automated code generation* months rather than years

definition of embedded software using the waveform description language,

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