1/29 July 10 th 2004 Department of Electronics and Telecommunications Laboratorio di Elaborazione...

Laboratorio di Elaborazione Numerica dei Segnali e Telematica 1/29 July 10th 2004Department of Electronics and Telecommunications

University of FlorenceDepartment of Electronics and Telecommunications

Cross Layer Protocols Design for Next Generation Wireless

Systems

Philosophiae Doctor Thesis

of Francesco Chiti

on

COURSE OF INFORMATICS AND TELECOMMUNICATIONS ENGINEERING

Tutors:

Prof. Enrico Del Re

Prof. Romano Fantacci


Outline

i. Introduction

1. Soft Combining techniques

2. Adaptive Link Control algorithms

3. Dynamic Bandwidth Allocation techniques

4. Routing protocols for Ad Hoc networks

5. Conclusions


“INTERNET”a pervasive, global, nervous system

Incoming communications systems

i. Introduction

Ubiquity

Em

beddedness N

omadicity

Cyberspace Physical space Alive environment

Universal roaming:Cellular & WiFi nws

Fast Broadband access Efficient transport Intelligence in the edge

Wireless (mobility) QoS support


Physical

Data Link

Network

Transport

Access Network (cellular/satellite)

Transport Network (TCP/IP)

Physical

Data Link


i. Introduction


Ad Hoc Network


i. Introduction

Physical

Data Link

Network

Transport

Cross Layer protocols designOptimization of adjacent layers aware

protocols

Cross layer adaptabilityAcross layers information passing and

functionalities adaptation to channel and load variations


For each MCS a bistable discrete Markov chain model can be derived based on the ACK/NACK reception (reliable services)

State 0: ACK reception State 1: NACK reception

0 1

r10

r01

r11r00

ACK driven protocol fundamentals


N Modulation and Coding Schemes (MCSs) with each:

• Modulation order Mi and code rate Rci

• throughput i


• Transition depends on ACKs reception

• Transition depends on NACKs reception

i i+1

ri+1,i

ri,i+1

iNACK

i+1N

NACK

ACK

NACK

1 ii ACKiN

ii 1 NACKiN 1



MAC

LLC




Optimal AD algorithm

11

1

11

,1

1,

1

N

ii

i

K kk

kk

i

P

Pr

rP

NACKkN

kk

k

kk

ACKkN

kk

k

kk

rr

rr

rr

rr

1

1,011,10

1,01

,1

,01,10

,10

1,

maximizing

N

iiii

PP1

,0

iP

,0 FER of the ith MCS

NACK

k

ACK

kNN ,


Theoretical analysis


N MCSs: steady state equations

1

0,1,1

02,1

0,1

0,,

1

01,

0,

1

0,1,1

2

0,1

0,1,

0,11,1,1

2

02,1

00,1

0,0,0

1

01,0

00,0,0

j

iijkikj

jk

iiijkj

k

iijj

j

iijkikj

jk

iiijkj

k

iijj

j

iijkikj

jk

iiijkj

k

iijjkj

kik

k

iiik

k

ii

kik

k

iiik

k

iik

papqaqpar

papqaqpar

papqaqparp

ppapqaqpar

papqaqparp

probability of being in i phase with j queued packetsjip ,

probability of having k packets arrivalska


Theoretical analysis


2 MCSs: steady state equations

0,0,0

1

01,0

01,0

1

0,1,1

2

02,1

01,1,1

0,11,1,1

2

02,1

00,1

0,0,0

1

01,0

00,0,0

papqaqpar

papqaqparp

ppapqaqpar

papqaqparp

kik

k

iiik

k

ii

iikik

k

iiik

k

iik

kik

k

iiik

k

ii

kik

k

iiik

k

iik

1

0 0,

i jjijpN

0

,110

,00j

jj

j pRpR 0,10,0 ppN

T


TU50 channel

• State 1: 4QAM Rc= 1/2• State 2: 16QAM Rc= 1/2• State 3: 16QAM Rc= 2/3• State 4: 64QAM Rc= 1/2• State 5: 64QAM Rc= 2/3

1 2 3 4 5 r55

r44r33

r11

r22

r54

r45

r43

r34

r21

r12

r32

r23

Application to TEDS systems



TU50 channel (17 dB, 22 dB)



TU50 channel @ 17 dB r00 r01 r11 r10 [bit/slot]

State 1: 4-QAM 21cR 0.9817 0.0183 0.1050 0.8950 27

State 2: 16-QAM 21cR 0.9026 0.0974 0.2044 0.7956 54

State 3: 16-QAM 32cR 0.8049 0.1951 0.3142 0.6858 72

State 4: 64-QAM 21cR 0.7355 0.2645 0.4219 0.5781 81

State 5: 64-QAM 32cR 0.5492 0.4508 0.6816 0.3184 108

TU50 channel @ 22 dB r00 r01 r11 r10 [bit/slot]

State 1: 4-QAM 21cR 0.9967 0.0033 0.0571 0.9429 27

State 2: 16-QAM 21cR 0.9807 0.0193 0.0913 0.9087 54

State 3: 16-QAM 32cR 0.9371 0.0629 0.1252 0.8748 72

State 4: 64-QAM 21cR 0.9099 0.0901 0.1874 0.8126 81

State 5: 64-QAM 32cR 0.7935 0.2065 0.3345 0.6655 108


HT200 channel

• State 1: 4QAM Rc= 1/2• State 2: 16QAM Rc= 1/2• State 3: 16QAM Rc= 2/3• State 4: 64QAM Rc= 1/2

1 2 3 4 r55

r33

r11

r22r43

r34

r21

r12

r32

r23




HT200 channel (11 dB, 16 dB)



HT200 channel @ 11 dB r00 r01 r11 r10 [bit/slot]

State 1: 4-QAM 21cR 0.9859 0.0141 0.0142 0.9858 27

State 2: 16-QAM 21cR 0.5787 0.4213 0.4462 0.5538 54

State 3: 16-QAM 32cR 0.0745 0.9255 0.9145 0.0855 72

State 4: 64-QAM 21cR 0.0069 0.9931 0.9855 0.0145 81

HT200 channel @ 16 dB r00 r01 r11 r10 [bit/slot]

State 1: 4-QAM 21cR 1 0 0 1 27

State 2: 16-QAM 21cR 0.9811 0.0189 0.0107 0.9893 54

State 3: 16-QAM 32cR 0.6828 0.3172 0.3222 0.6778 72

State 4: 64-QAM 21cR 0.4501 0.5499 0.5736 0.4264 81


• Uniform Cell quantization

• Several suitable mobility model

• Performance evaluation for each circular region



R RR R R

Channel Model Es/N0 at the receiving end [dB]

HT200 11 13 16 20 29

TU50 17 19 22 26 35

Mobility management




Mobility management

R

30°

15°

1

2

Rectilinear mobility models

1

R

Outdoor walk mobility modelRandom waypoint model



Global AD algorithm

maximizing for each scenario

s=1,…,S

s

NACK

ks

ACK

kNN ,


1

1 11

1,

,

1

1 11

1,

,

,1,1

11

111

N

k

k

i

NACKiN

ie

ACKiN

ie

N

k

k

i

NACKiN

ie

ACKiN

ie

keke

P

P

P

PPrPr

maximizing for all the S scenarios

NACK

k

ACK

kNN ,

S

ssMAX

NACK

k

ACK

ksNN

1

2

,

sMAX ,

lower computational complexity

O-ALC

G-ALC


Simulation results

Operative assumptions

• Traffic model: WWW application, consisting of a sequence of file downloads [3GPP 25.933]

k = 1858 m = 66,666 / 5,000,000 = 1,1

• Variable file request rate depending on considered loading factor

mxm

k

mxkx

k

xf,

,)(

1




Simulation results

Operative assumptions

• Slow feedback channel due to the semi-duplex operation: (N)ACK knowledge delay equal to 4 slot duration time (4 13.3 ms)

• Dedicated allocation scheme: only 1 carrier is allocated to each user




HT200 @ 11 dB: N



Noticeable gain even in hard propagative conditions

HT 200 @ 11 dB

0

25

50

75

100

0,0 0,2 0,4 0,6 0,8 1,0

Loading Factor

Bu

ffer

Len

gth

[P

DU

]

Basic

G-ALC

O-ALC


HT200 @ 11 dB: T



HT200 @ 11 dB

0

500

1000

1500

2000

2500

0,0 0,2 0,4 0,6 0,8 1,0

Loading Factor

PD

U q

ueu

e w

aiti

ng

tim

e [s

]

Basic

G-ALC

O-ALC


TU50 @ 22 dB: N



Network capacity increasing

TU50 @ 17 dB

0

25

50

75

100

0,0 0,5 1,0 1,5 2,0 2,5

Loading Factor

Bu

ffer

Len

gth

[P

DU

]

Basic

G-ALC

O-ALC

+170%


TU50 @ 22 dB: T



Network capacity increasing

TU50 @ 22 dB

0

25

50

75

100

125

150

0,0 0,5 1,0 1,5 2,0 2,5

Loading Factor

PD

U q

ueu

e w

aiti

ng

tim

e [s

]

Basic

G-ALC

O-ALC

+170%


0

0,5

1

1,5

2

2,5

3

Basic G-ALC O-ALC

No

rma

lize

d t

hro

ug

hp

ut

+200% HT200 11dB

HT200 16dB

TU50 17dB

TU50 22dB



HT200 & TU50 :


TU50

0

0,5

1

1,5

2

2,5

3

3,5

Basic G-ALC O-ALC

Nor

mal

ized

thro

ughp

ut

+168% +175%

R

30°

15°

1

2

Rectilinear mobility models



TU50 & mobility :


TU50

0

0,5

1

1,5

2

2,5

3

3,5

Basic G-ALC O-ALC

Nor

mal

ized

thro

ughp

ut

+228% +230%

Outdoor walk mobility model



1

R

TU50 & mobility :


TU50

0

0,5

1

1,5

2

2,5

3

3,5

Basic G-ALC O-ALC

Nor

mal

ized

thro

ughp

ut

+205% +208%

Random waypoint model



R RR R R

TU50 & mobility :




HT200 channel

0

1

2

3

10 15 20 25 30

SINR [dB]

No

rma

lize

d t

hro

ug

hp

ut

BasicMCS 2MCS 3MCS 4G-ALCO-ALC

G-ALC closely approaches O-ALC with lower complexity

HT200 & mobility :


Conclusions• ALC algorithm based on the ACK/NACK messages provided by

the MAC layer (cross-layer design)

• Thresholds selection by means of optimizing the link effective throughput

• Generalization to the case of several mobility models within a cell

• Application to the case of TEDS system

Publications1. L. Caponi, F. Chiti, R. Fantacci: “An Efficient Rate Allocation Technique based on Channel

Status Observation for Wireless Communication Systems”, in Proc. of IEEE WCNC 2004.

2. L. Caponi, F. Chiti, R. Fantacci: “A Dynamic Rate Allocation Technique for Wireless Communication Systems ”, in Proc. of IEEE ICC 2004.

3. L. Caponi, F. Chiti, R. Fantacci: “Performance Evaluation of a Channel Aware Link Adaptation Technique for High Speed Wireless Communication Systems”, submitted to Trans. On Vehicular Technology.

4. F. Chiti, R. Fantacci, D. Tarchi, ETSI TEDS Channel Coding STF 179, “WG403036 Adaptive Link Control” Tech. Rep., 04 2004.


University of FlorenceDepartment of Electronics and Telecommunications

Cross Layer Protocols Design for Next Generation Wireless

Systems

Philosophiae Doctor Thesis

of Francesco Chiti

on

COURSE OF INFORMATICS AND TELECOMMUNICATIONS ENGINEERING

Tutors:

Prof. Enrico Del Re

Prof. Romano Fantacci

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