Dhananjay Kumar Anna University, Chennai, India … · Dhananjay Kumar Anna University, Chennai,...

Mar del Plata, Argentina, 31 Aug – 1 Sep 2009

ITU-T Kaleidoscope 2009Innovations for Digital Inclusion

Dhananjay KumarAnna University, Chennai, IndiaEmail: [email protected]

DYNAMIC RESOURCE MANAGEMENT FOR DOWNLINK MULTIMEDIA TRAFFIC IN OFDMA CELLULAR

NETWORKS

Mar del Plata, Argentina, 31 Aug – 1 Sep 2009 ITU-T Kaleidoscope 2009 – Innovations for Digital Inclusion 2

Presentation Outlines

Multimedia ServicesMulti Carrier SystemsOFDMA System ModelProblem FormulationTwo Stage Rate Adaptive (TSRA) Algorithm

Bandwidth Adaptive (BWA) algorithm

Results & Discussions


Mobile Multimedia Services

Multimedia over Mobile NetworkTextImagesVideoAudio

QoS SupportDynamic & Efficient Resource Requirements

MPEG-4 video trace (Die Hard III)

Frame Size

Frame IndexCourtesy: Technical University, Berlin : http://www.tkn.tu-berlin.de/research/trace/ltvt.html

Mar del Plata, Argentina, 31 Aug – 1 Sep 2009 ITU-T Kaleidoscope 2009 – Innovations for Digital Inclusion


Quality Trace Compression Ratio

YUV:MP4

Frame Size Bit Rate

Mean Cov Peak/ Mean

X [kbyte] σ2/X Xmax/X^

Mean Peak

X/t[Mbps] Xmax/t[Mbps]

High Jurassic Park I

Silence of the Lambs

Star Wars IV

9.92

13.22

27.62

3.8 0.59 4.37

2.9 0.80 7.73

1.4 0.66 6.81

0.77 3.3

0.58 4.4

0.28 1.9

Medium Jurassic Park I


Star Wars IV

28.4

43.43

97.83

1.3 0.84 6.36

0.88 1.21 13.6

0.39 1.17 12.1

0.27 1.7

0.18 2.4

0.08 0.94

Low Jurassic Park I


Star Wars IV

49.46

72.01

142.52

0.77 1.39 10.61

0.53 1.66 21.39

0.27 1.68 17.57

0.15 1.6

0.11 2.3

0.053 0.94

Trace File of Some Hollywood Movie

Courtesy: Technical University, Berlin : http://www.tkn.tu-berlin.de/research/trace/pub.html

MPEG-4 Advanced Audio Coding

Courtsey: Fraunhofer IISMar del Plata, Argentina, 31 Aug – 1 Sep 2009 ITU-T Kaleidoscope 2009 – Innovations for Digital Inclusion

Telephone codec

Speech codec

(Speech)

Speech codec

(Music)

ULD 80 kbps

AAC-ELD64 kbps

AAC-LD64 kbps AAC-ELD

32 kbps

AAC-LC56 kbps MP3

64 kbps

HE-AAC20 kbps

Audio quality

CD like Quality (BW>15 KHz)

Wide Band (BW 7 KHz)

Narrow Band (BW 3.5 KHz)

Algorithmic delay in ms

10 20 30 40 50 100 130

AAC: Advanced Audio Coding ULD: Ultra-Low-Delay AAC-ELD: Enhanced Low Delay AACAAC-LD: Low Delay AAC

AAC-LC: Low Complexity AACHE-AAC: High-Efficiency AAC

Service classification and service parameters


User Experience Class

Service Class Service Parameters (Numerical Values)

Conversational Basic conversational service

Throughput: 20 kbit/sDelay: 50 ms

Rich conversational service

Throughput: 5 Mbit/sDelay: 20 ms

Conversational low delay

Throughput: 150 kbit/sDelay: 10 ms

Streaming Streaming Live Throughput: 2 – 50 Mbit/s

Delay: 100 msStreaming Non-Live Throughput: 2 – 50 Mbit/s

Delay: 1 sInteractive Interactive high delay Throughput: 500 kbit/s

Delay: 200 msInteractive low delay Throughput 500 kbit/s

Delay 20 msBackground Background Throughput: 5 – 50 Mbit/s

Delay: < 2s

Guidelines for evaluation of radio interface technologies for IMT-Advanced

Source: Document 8F/TEMP/568

Multi-Carrier Communication in Next Generation Networks

Higher CapacityCan approach theoretical limit

Easy support for adaptive resource Allocation

The Concept of Sub Channel/Carrier

Ability to combat inherent problems in wireless


Diffraction

Line of sight

Scattering

Reflection

Reflection


Multi Path Propagation


Channel Response in Freq. Domain

f

|H(f)|

Frequency

Power

Frequency

PowerBSBS


The Concept of Multi-carrier

Multi-Carrier Communication Systems

MC-CDMASuitable for indoor wireless environmentFading resistance using frequency diversity Need for rake receivers

OFDMAHandling of multipath fading (ISI)Spectral efficiencyNo intra-cell interference (No Cell breathing)


OFDMA System Model


Allocation information

Wireless channelto user k

Sub carrier and bit allocation scheme (M-QAM)

IFFT and parallel to serial

Add cyclic prefix

Symbos to bit mapping

Su carrier selector

FFT and serial to parallel

Remove cyclic prefix

Subcarrier 1

Subcarrier N

Subcarrier 2

User

N

1

2

Problem Formulation

),( min kkk

in NN αΦ=

kk

k ∀=∑ ,1α

⎟⎟⎠

⎞⎜⎜⎝

⎛−

−=1

5.1exp51

MSINRBER

ii

Initial subcarrier allocation:

αk is chosen such that 0 ≤ αk < 1 while satisfying the condition

To calculate Nmin , we first compute BER of the sub channel. The BER of ith subcarrier using M-QAM can be approximated by.


Problem Formulation cont.

MNBR i

sb 2log=

⎥⎥⎥⎥

⎥

⎤

⎢⎢⎢⎢

⎢

⎡

=

∑=

kN

i

isb

kk

R

RN

1

min

The order of modulation M for the ith sub carrier ischosen such that the BER < 10-3.In M-QAM the maximum capacity could be approximated by

If Rk is the minimum bit rate needed to support an application k, and Ri

sb is the bit rate supported on the ith sub carrier, then the minimum no of required sub carrier is given by


Problem Formulation cont.


ikl

ikl

L

l

K

k

N

i

ikl CINRp

l k

,,1 1 1

, )(∑∑∑= = =

α

∑∑∑= = =

=L

l

K

k

N

i sbk

ikl

av

l k

BWNR

C1 1 1

,

)(

Considering L types of applications, the sub carrier selection can be definedas optimization of

such that average capacity (bits/second per Hz), Cavrepresented below is maximum.

Development of TSRA Protocol


Rth2

Rth1

Packet/Time unit

Time Units

The BWA Algorithm


A

If Ri changes from Rth1 to

Rth2

Assign Mean ValueRti= (Rt1+ Rt2)/2

Allocate from nrt-VBR & ABR till

Rti = Ri+Riac

No No

Yes

Starts de-allocation & share among ABR &

nrt-VBR

No

Yes

If Rifluctuates Rth1≤Ri≤Rth2

Initialize Rth1, Rth2, Ri

START

Vary the modulation order to meet the

requirements

Is ΔRi is small

Monitor the change in input data rate (ΔRi) in every tmin

duration

END

Is call disconnected?

Yes

No

Is Ricentered

around Rth1or Rth2

Yes

No

Wait for tmin. Same

status ?

Yes

Wait for tmin. Ri at

Rth2?

Wait for tmin. Is ΔRi>rth?

Wait for tmin. Ri at

Rth1?

Yes

If Ri changes from Rth2 to

Rth1

A A

A

Yes Yes Yes Yes

No No

A

No

No

Average Capacity


2 4 6 8 10 12 14 161

2

3

4

5

6

7

Number of Users

Ave

rage

Cap

acity

(bit/

s/H

z)AnalyticalTSRA with BWATSRA without BWA

Throughput per OFDM Symbol


2 4 6 8 10 12 14 16

0.7

0.8

0.9

1

1.1

1.2

1.3

1.4

Number of Users

Thro

ughp

ut (M

bps)

per

OFD

M S

ymbo

l

TSRA with BWA and AMTSRA without BWA and AMTSRA with BWA without AM

Average delay for rt-VBR traffic


2 4 6 8 10 12 14 160

0.01

0.02

0.03

0.04

0.05

0.06

Number of Users

Ave

rage

Del

ay (S

econ

ds)

Average BER


2 4 6 8 10 12 14 160.5

1

1.5

2

2.5

3

3.5

4

4.5x 10

-3

Number of Users

Ave

rage

BE

R

CONCLUSION

Multi-carrier can support future multimedia servicesThe OFDMA based system offers high capacity / efficiency The TSRA algorithm can meet the QoS requirement of high quality multimedia applications while approaching theoretical limit (more than 6b/s/Hz for 128-QAM)



Thank You Very Much

Dhananjay Kumar Anna University, Chennai, India … · Dhananjay Kumar Anna University, Chennai,...

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