c/c++ based simulation techniquesc3%d6%c7%f6... · 2012-03-20 · e1-data path of ap upper layer...

삼성종합기술원

최현호

[email protected]

C/C++ Based Simulation Techniques

KRnet 2008

II

IIII

IIIIII

IVIV

네트워크 시뮬레이션 개요

4 KRnet 2008

Presentation OverviewPresentation Overview

목적– 이동통신시스템의 시스템 레벨 시뮬레이션 및 알고리즘 시뮬레이션을 위한 방법론 및

기본 C/C++ 테크닉 소개

대상– 이동통신시스템의 SW 구현을 원하는 자– 이동통신시스템의 시스템 레벨 시뮬레이션을 원하는 자– 제안한 통신 알고리즘의 시뮬레이션을 원하는 자– 시뮬레이션에 필요한 기본 C/C++ 테크닉의 습득을 원하는 자

소개 내용– 시뮬레이션의 개요

• 이동통신 시스템 개요• 시뮬레이션 과정

– C/C++ 기반 시뮬레이션 방법론• 시스템 설계 방법론• C/C++ 시뮬레이션 테크닉

– C/C++ 기반 시뮬레이션 예제• HiperLAN Type2 MAC protocol simulation• WiBro System level simulation

– 시뮬레이션 툴 소개• SDL

5 KRnet 2008

Why Simulation…?Why Simulation…?

High complexityHardware-dependent Hard to understand

Systems Algorithms

Simulation(Modeling & SW 구현)

Conceptually simpleSoftware-orientedReusable

1. Performance Analysis 2. Behavioral Analysis3. Test-bed Development

• Objectives: Numerical Analysis와비교HW 구현전테스트, 리스크감소시스템최적화

• Modeling/Simulation Tools: 1. CHILL, SDL, ObjectTime (Modeling language)2. C/C++, MATLAB (Numerical tool 제공)3. Network Simulator (NS-2, OPNET, etc.)

• Signal Processing• Medium Access Control• Network• Artificial Intelligence

• Communication• Network• Economy• …

6 KRnet 2008

Communication ProtocolCommunication Protocol

OSI model

- Traffic modeling (HTTP, FTP, Voice, Video)Network process to application

Data

7. Application

- MAC protocol- Random access control algorithm- Scheduling algorithm, etc.

Physical addressing (MAC & LLC)

Frame 2. Data link

- Channel modeling- Link level simulation- Signal processing algorithm, etc.

Media, signal and binary transmission

Bit1. Physical

- IP packet modeling- Routing algorithm- Congestion control algorithm

Path determination and logical addressing (IP)

Packet 3. Network

- Connection management- TCP/UDP modeling- TCP algorithm

End-to-end connections and reliability (TCP)

Segment/Datagram

4. Transport

- Session SynchronizationInterhostcommunication

5. Session

- Security Control- Meta data format

Data representation and encryption

6. Presentation

SimulationFunctionData unitLayer

7 KRnet 2008

Communication AlgorithmCommunication Algorithm

Net

wor

kPh

ysic

alD

ata

link

Radio Resource Management(CAC, Res Alloc.)

Scheduling (RR, PF, QoS)

Medium Access Control(Random access control)

Modem

Duplexing

Multiple Antenna (Diversity, Multiplexing, BF,

Multiuser diversity)

Multiple Access (xDMA)

Channel Equalization

Channel Estimation

Interference Cancellation

Synchronization

Multiuser Detection

Channel Coding

ARQ

QoS mapper/classifier

Handover Algorithm

Sleep/Idle mode

Handover Signaling

Mobility Management(Registration, Mobile IP, etc.)

AAA

Security

Basic Algorithms & Functions

Algorithmentity

Functionalentity

8 KRnet 2008

Communication PathCommunication Path

9 KRnet 2008

Wireless Channel (1)Wireless Channel (1)

Object– Receiver에서 SINR (Signal-to-noise-and-interference ratio)를 알고자 함

Link budget– PRX = PTX + GTX - LTX - LFS - LM + GRX – LRX

• PRX = received power (dBm) • PTX = transmitter output power (dBm) • GTX = transmitter antenna gain (dBi)• LTX = transmitter losses (coax, connectors...) (dB) • LFS = free space loss or path loss (dB)• LM = miscellaneous losses (fading margin, body loss, polarization mismatch,

other losses...) (dB)• GRX = receiver antenna gain (dBi)• LRX = receiver losses (coax, connectors...) (dB)

Transmitter Receiver

10 KRnet 2008


Path loss– LFS = 10n log(d) [dB]

• n: path loss exponent• d: distance

Fading margin– Long-term fading (Shadowing)

• log-normal distribution

– Short-term fading• Rayleigh distribution: outdoor, 다중 반사파가 직접파보다 셀 때

• Rician distribution: indoor, 다중 반사파보다 직접파의 세기가 강할때

⎥⎥⎦

⎤

⎢⎢⎣

⎡ −−= 2

2

2)(

exp2

1)(y

y

y

myyp

σσπ

⎥⎦

⎤⎢⎣

⎡−= 2

2

2 2exp)(

rr

rrrpσσ

⎟⎟⎠

⎞⎜⎜⎝

⎛ −⎥⎦

⎤⎢⎣

⎡ +−= 202

22

2 2exp)(

rrr

arIarrrpσσσ

11 KRnet 2008


Noise– Thermal noise를 가정

– Pnoise = -174 + 10 log(Δf) [dBm]

Interference– 원하는 신호가 아닌 다른 모든 신호의 합

– Wrap around 방식 사용: multi-tier 고려

SINR & Capacity– SINR = S/(I+N)– Link level에서의 이론적인 capacity

• Shannon Limit에 의해 maximum boundary가 결정

• C = BW log2(1+SINR)

– System level에서의 실제 capacity • Physical layer: 알고리즘에 따라 수신한 SINR을 BER/PER로 매핑

• MAC layer: 알고리즘에 따라 PER을 이용하여 실제 throughput, delay 등 파악

∑∀≠

=iji

RXPI,

Interference 고려를위한셀구성방식

1st tier

2nd tier

12 KRnet 2008

Simulation StepSimulation Step

Requirements Specification and

Analysis

Modelingand

DesignCoding

andUnit Testing

Integrationand

System TestingResultand

Maintenance

(What?)

(How?)

(Do it)

(Test it)

(Deliver it)

Waterfall Model

C/C++ 기반 시뮬레이션 방법론

14 KRnet 2008

Simulation Process (1)Simulation Process (1)

Algorithm Level Simulation Problemformulation

Setting objectivesPerformance index

Modelconstruction

Datacollection

Coding

Verified?

Validated?

Experimentdesign

Experimentations

Output analysis

Yes

Yes

No

No

Design

Implem

entation

15 KRnet 2008

Simulation Process (2)Simulation Process (2)

시스템다이어그램

블록다이어그램

프로세스다이어그램

테스트 / 디버깅

결과도출

코드생성

시뮬레이션

Design

Implem

entation

• Model Design: Top-down Approach• Model Implementation: Bottom-up Approach

System Level Simulation

16 KRnet 2008

시스템/블록 다이어그램 설계시스템/블록 다이어그램 설계

BS system

Network

MAC

PHY

…

• 일반적으로통신을하는두 entity는대칭적인시스템 layer를가짐• 세부프로세스는다름

Proc_Routing

Proc_classify

…

Proc_Schedule

Proc_Access…

Proc_TX

Proc_RX…

MS system

Network

MAC

PHY

…

…

시스템레벨

블록레벨

프로세스레벨

17 KRnet 2008

프로세스 다이어그램프로세스 다이어그램

프로세스

– Coding이 용이하도록 순서도 작성

– SDL (Specification and Description Language) 이용 가능

18 KRnet 2008

프로그램 구조프로그램 구조

Main function ManagementCommon Shared

Local variables

Algorithm process

Function process

Global variables

Common functions

Macro

Math functions

Initiation

Termination

Local variables

Scheduling

Traffic generation Statistics / Result

Structure

Coordination

Event Mng.

Timer Mng.

Signal Mng.Local function

Sub-functions

Library

Node 수 (Tx, Rx)에따라 multiple로존재가능

Measurement

19 KRnet 2008

Event Handler (1)Event Handler (1)

Untimed event – Signaling 처리 (Virtual time)– Unordered/partial ordered

Timed event– Timer 처리 (Real time)– Totally ordered

S2S1 S3

State/event sequence Timed state/event sequence

e1 e1 e2 e2S2S1 S3

e1 e1:T1 e2:T2 e2

Time variables– t: current time– tL: time of last event– tN: time of next event– e: elapsed time

Messages– (x,t): external input event arrival at time t– (*,t): internal event notifying that schedule time comes– (y,t): output event generated at time t– (done, tN): synchronization event notifying next event time is tN

두개의 event를 handling 하는 coordinator 존재

20 KRnet 2008

Event Handler (2)Event Handler (2)

Coordination– Timed event와 untimed event가 논리적인 흐름에 따라 수행되도록 스케쥴

링 해줌

– Timed event• Periodic: 주기적인 시간에 따라 발생함

• Non-periodic: event에 따라 발생함

– Untimed event• Signaling process: logically 시간의 흐름이 없다고 가정

time

Timed event

Untimed event

P1 P1 P1 P1 P1

S1

S2

S1

S2

S3

P2

S1

P2

21 KRnet 2008

Verification & ValidationVerification & Validation

Verification– SDL과 code의 확인

– 코드 debugging

Validation– 알고리즘 별 numerical analysis 수행하여 비교

– 다양한 test vector를 만들어 시스템 레벨에서 검증 가능

22 KRnet 2008

C/C++ Technique (1)C/C++ Technique (1)

Structure– packet, signaling message, event 등의 다양한 정해진 형태의 변수

를 구조체로 정의

– struct packet 의 예

ID address size data

typedef struct { // packet struct 정의char ID;int address[2];unsigned int size;double data;

} packet;

packet format

packet IP_pkt; // packet 타입의 IP packet 선언

IP_pkt.ID = 1; // member 변수의 값 입력IP_pkt.address = 0x12AB;IP_pkt.size = 15;IP_pkt.double = xxxx;

23 KRnet 2008


Global variable– 모든 file, 함수에서 사용하는 변수를 선언

– “global.h”와 같은 header file을 만들어 사용

Pointer– int *ptr1, ptr2; – *ptr1: 포인터가 가리키는 번지에 들어있는 값을 나타냄

– &ptr2: 변수가 기억되어 있는 메모리의 번지를 나타냄

동적 메모리 할당

– Traffic 관리 및 event handler 관리에 사용

– void *malloc (size_t size);– void *calloc (size_t ntimes, size_T size);– void free (void *block)

// file: global.hint glo; char key;

#include <global.h>void func(){

int local;char ch;

}

24 KRnet 2008


Linked list– Timer/signal event 관리에 적합

– Node와 Node pointer로 구성

struct node {int data;struct node* next;

};

Insertion Deletion

C/C++ 기반 시뮬레이션 예제

26 KRnet 2008

ExamplesExamples

Example 1– HiperLAN Type2 MAC protocol simulation

Example 2– WiBro System level simulation

27 KRnet 2008

E1- Data Path of MTE1- Data Path of MT

Upper Layer (LLC)

Physical LayerTxDataRxData

Management

MmRequest

MmIndicate

UnitData=SA//DA//LLCdata

FragData = Segment(UnitData) :

LCHs의 Array

TxDataOctet_String형

태 RxDataOctet_String형

태

Downlink Data 분리(SCH, LCH)

Broadcast 메시지 분리

(BCH, FCH, ACH)

Broadcast Downlink

RxBuffer 에 LCH 저장

LCHsSCH (ARQ)

TxBuffer저장LCH의 Array

Resource Request

전송(RCH)

Uplink Data 전송

(SCH, LCH)

Tx_Coordination_STA

MAC

Protocol_Control_STA

Uplink

UnitData Indication

UnitData로 부터 (SA, DA, LLCdata)추

출

FragDataf로 부터 SA, DA 추출

Rx Ack

Data

Management

802.11a의FramControl

첨가

28 KRnet 2008

E1- Data Path of APE1- Data Path of AP

Upper Layer (LLC)

Physical Layer

TxDataRxData

Management

MmRequest

MmIndicate

UnitData=SA//DA//LLCdata

FragData = Segment(UnitData) :

LCHs의 Array

TxDataOctet_String형

태 RxDataOctet_String형

태

Uplink Data 분리(SCH, LCH)

RCH 메시지 수신(RCH)

RCH Uplink

단말 MACID별 RxBuffer 에

LCH 저장

LCHsSCH (ARQ)

MACID별 TxBuffer저장(LCH의 Array)

Broadcast정보 전송

(BCH, FCH, ACH)

Downlink Data 전송

(SCH, LCH)

Tx_Coordination_AP

MAC

Protocol_Control_AP

Uplink

UnitData Indication

UnitData로 부터 (SA, DA, LLCdata)추

출

FragDataf로 부터 SA, DA 추출

Rx Ack

Data

Management

802.11a의FramControl 첨가

29 KRnet 2008

E1- SDL of All SystemE1- SDL of All System

30 KRnet 2008

E1- 프로그램 구조E1- 프로그램 구조

DummyPhy_Proc()

main()

MSDU_from_LLC_AP()

Rx_CHs_AP()Tx_CHs_AP()

Scheduling()

Rx_Coordination_AP()Tx_Coordination_AP()

Prepare_MPDU_AP()

MSDU_to_LLC_AP() MSDU_from_LLC_STA()

Rx_CHs_STA() Tx_CHs_STA()

Tx_RR()

Rx_Coordination_STA() Tx_Coordination_STA()

Prepare_MPDU_STA()

MSDU_to_LLC_STA()

LLC

AP

PHY

STA

MANAGEMENT

Reset_STA()Reset_AP()

Reset

Event_Out()ViewEvent()

ViewEventName()ViewEventState()

ExeEvent()

Event

InitSignalQ()SetSignalEvent()GetSignalEvent()

Signal

InitTimer()GetTimerEvent()SetTimerEvent()

SetTimerEvent_AP()ViewTimerQ()

ViewTimerQ_AP()Now(),Now_AP()

Timer

31 KRnet 2008

E2- Link-Level vs. System-Level (1)E2- Link-Level vs. System-Level (1)

Link-Level:– Goal: Study different signal

transmission and reception schemes

– Single Link– Single Cell– Single Base Station– Emphasis on PHY– Some MAC

System-Level:– Goal: Application level

performance– Multiple users– Multiple cells– Multiple Base Stations– Emphasis on all layers

PHY abstracted

PHY

MAC

Network

Application

MAC

Network

Application

PHY

※ Ref: Raj Jain et al, " WiMAX System Level Modeling,” http://www.cse.wustl.edu/~jain/wimax/gc07.htm

32 KRnet 2008

E2- Link-Level vs. System-Level (2)E2- Link-Level vs. System-Level (2)

Link-LevelSimulator

System-LevelSimulator

SystemPlanning

Transmitter structure

Channel impulse response

Receiver structure

Network layout

Cell configuration

Propagation model

Mobility model

Traffic model

Service requirements

SINR vs PER table

Performances

ConfigurationRequirements

33 KRnet 2008

E2- System-Level ComponentsE2- System-Level Components

MAC

Network

Application

PHY

System Topography (Cell size, Height, Cell size, User density)

Traffic generation (VoIP, VoD), QoS requirement

TCP/UDP, IP, RTP, Buffering, Handover

Scheduling, ARQ, Interference from other systems

Channel model, Coding, Antenna (MIMO), Multiple access

34 KRnet 2008

E2- TopologyE2- Topology

Target cell을 중심으로 계산

N-th tier의 interference 고려

단말은 각 cell에 uniform-randomly 분포

Base station

Terminal

Target Cell

1st tier

2nd tier

35 KRnet 2008

E2- Interference ModelingE2- Interference Modeling

Downlink SINR– 동일시간에 동일한 downlink

자원을 사용하는 타 기지국으로부터의 시그널이interference로 작용

S

I1 I2

I6

I5 I4

I3

Uplink SINR– 동일시간에 동일한 uplink 자

원을 사용하는 타 기지국내의단말로부터의 시그널이interference로 작용

S

I2I1

I3

I4I5

I6

36 KRnet 2008

E2- Traffic ModelingE2- Traffic Modeling

Simplified traffic model– Ref: 3GPP2, “1xEV-DV Evaluation Methodology – Addendum (V6),” 2001

37 KRnet 2008

E2- Simulation 구조E2- Simulation 구조

38 KRnet 2008

E2- Link Level 결과 (1) E2- Link Level 결과 (1)

Link level simulation 결과

– SINR vs. PER 결과 도출

– PER 결과를 MAC layer에 report

39 KRnet 2008

E2- Link Level 결과 (2)E2- Link Level 결과 (2)

Link level simulation 결과

– 사용자 분포에 따른 평균적인 AMC 사용 비율을 구하여 MAC layer에 반영

0.00364QAM 5/6

0.04264QAM 2/3

0.02416QAM 3/4

0.2397516QAM 2/30.06416QAM 2/3

0.111516QAM 1/20.15616QAM 1/2

0.10158316QAM 1/30.057QPSK 2/3

0.136667QPSK 1/20.228QPSK 1/2

0.180333QPSK 1/30.206QPSK 1/3

0.15425QPSK 1/60.15QPSK 1/6

0.075917QPSK 1/120.07QPSK 1/12

UL 사용자 비율DL 사용자 비율

40 KRnet 2008

E2- System Level 결과E2- System Level 결과

Performance Measures– Throughput

• Total MAC throughput• MAC throughput of each session (VoIP, Video, HTTP, FTP)• MAC overhead (PHY throughput / MAC throughput)

– Delay• Average delay of all sessions (VoIP, Video, HTTP, FTP)• Average delay of each session (VoIP, Video, HTTP, FTP)• Handover delay

– Downlink & Uplink Resources• Assigned uplink resources to the SS & Used uplink resources by the

SS• Assigned downlink resources to the SS

– Etc.• Transmitted packet sizes of downlink & uplink• Original packet sizes of each traffic generator (VoIP, Video, HTTP,

FTP)• Band AMC effect• HARQ effect

기타 시뮬레이션 툴

42 KRnet 2008

SDL (1)SDL (1)

SDL– Specification and Description Language– International standard by ITU-T(Z.100)– Object-oriented language– Message based description– Complete operational semantics and execution model– Independent of implementation language– Systems can be realized in both software and hardware

SDL components– Architecture: Blocks– Behavior: Processes– Communication: Signals and Channels – Data and Functions: Abstract Data Types

43 KRnet 2008

SDL (2)SDL (2)

Graphical and textual representation이 존재

– SDL-PR(Phrasal Representation): textual syntax만을 사용

– SDL-GR(Graphical Representation): graphical component뿐만 아니라 textual representation에서 사용되는 것과 동일한 textual part를 사용

SDL은 FSM을 기반으로 만들어졌으며 각 state는 임의의 순간에 SIGNAL을 받거나 전송할 수 있도록 정의 되어 있음

Real Time System 설계에 적합

44 KRnet 2008

SDL (3)SDL (3)

SDL 시스템은 시스템 내의 중요한 요소들이 서로 어떻게 상호작용 하는지보이기 위해 최소한 하나 이상의 Block으로 구성되고 그 Block은 하나 이상의 Process를 포함하며 Process내에 자세한 동작이 기술됨

아래 그림은 system X안에 block Y가 존재하고, block Y안에 process Z가 존재하는 것을 보여줌 (c1,c2는 channel명이고 r1,r2는 signal route)

system X;channel c1 …… end channel c1;channel c2 …… end channel c2;block Y;

signalroute r1 ……;signalroute r2 ……;process Z referenced;……

endblock Y;……

endsystem X;

SDL-GR SDL-PR

system X

block Y

process Zc1 r1 r2 c2

.... .................... .... ....

.........

.........

.........

.........

45 KRnet 2008

SDL (4)SDL (4)

Four main hierarchical levels in SDL: system, block, process, and procedure

System Example Block Bl1

Process Proc2 Procedure Pr1

C1

C3

Bl1

Bl2

C2

............

...... ......

......

......

......

Proc1

Proc2

R1

R3

R2

......

......

......

Pr1

State1

......

Pr1

46 KRnet 2008

SDL (5)SDL (5)

Communication

Proc1 Proc2R1 R2

......

Block Bl1

Proc1 Proc2

SIGNALSig1(Integer);

Sig1

Signal declaration

Sending process Signal list

Receivingprocess

Sig1(5) Sig1

(Number)

DCLNumber Integer;

Output symbol Input symbol

47 KRnet 2008

Data Properties Data Properties

PreDefined data– Integer, Real, Boolean, Character, Duration, Time, etc.

ConstantsUser defined data typeANY– 지정된 데이터 타입의 Random 값을 리턴

• var:= ANY(Integer);ARRAY

48 KRnet 2008

System SpecificationSystem Specification

A Complete specification in SDL– A system must have at least a block specification– Pre-defined types are to be defined at system level

Three parts– System declaration part– Block interaction part– Process body

Syntax of a system specification– Graphical representation– Textual representation

system X

block Y

process Zc1 r1 r2 c2

.... .................... .... ....

.........

.........

.........

.........

49 KRnet 2008

Process BodyProcess Body

Syntax states and transitions– Graphical representation: uses flow chart– Textual representation: uses textual code

Declaration of variables– dcl <var name> type [:= <expression>;

예: dcl x1, x2 Integerdcl st Boolean:=true;

50 KRnet 2008

Time & DurationTime & Duration

Time– Processes in SDL may access global time by using the pre-

defined expression Nowdcl x1 Time;dcl diff Duration;

51 KRnet 2008

Process 의 구현Process 의 구현

System Example Block Bl1

Process Proc2 Procedure Pr1

C1

C3

Bl1

Bl2

C2

............

...... ......

......

......

......

Proc1

Proc2

R1

R3

R2

......

......

......

Pr1

State1

......

Pr1

프로세서의 표시

신호의 흐름을 표시

신호의 내용을 표시함

변수 선언부

프로세스의 시작을 나타내는 state

입력을 나타내는 기호

프로시져의 호출

프로시져의 구현

Operation을 수행:a:= a+1;

SET(timer);Reset(timer);

종료

52 KRnet 2008

System

Block

Process

53 KRnet 2008

사용되는 signal:Init -> 처음에 ENV_Tx channel을 통해 Transmitter에 넘겨줌.

Data(Integer) 에서 Data는 변수 이름, 괄호 안은 그 타입

C 언어의 struct와 같은 개념

54 KRnet 2008

Process를 의미함

55 KRnet 2008

56 KRnet 2008

시작

상태를 나타냄

Init signal을 입력으로 받아들임:C 언어의 함수의 call by value와 유사

In C statement:Total = con_sig.Tot_num;

타이머를 셋트함타이머는 inter라는 시간동안 지난후 expire

비교 분기문

Ch2를 통해 data(0)의 값을 출력

57 KRnet 2008

58 KRnet 2008

Flexible Integrations with Other LanguagesFlexible Integrations with Other Languages

SDL Suite는 C와 C++ code와의 인터페이스를 지원

이때 C와 C++ code는 UML Suite로부터 생성되거나 개발자에 의해 만들어진 것임

각 sub-system에 따라 최적의 implementation을 위해 C++혹은 SDL을이용하는 것이 가능

Requirements capture and analysis

C++ SDL

Final application, e.g. UMTS product

Data handlingAlgorithms

CommunicationEvent-Triggered

C++ code generation UML to SDL translation

C++interface

59 KRnet 2008

Message Sequence ChartMessage Sequence Chart

동작 확인: MSC

A_SUBSCR B_SUBSCREXCHANGE

OFF_HOOK

RING_TONE

FIRST_DIGIT

LAST_DIGIT

CALL

OFF_HOOK

ON_HOOK

Message Instance

감사합니다.

c/c++ based simulation techniquesc3%d6%c7%f6... · 2012-03-20 · e1-data path of ap upper layer...

Documents