ITU-T Kaleidoscope 2009
Innovations for Digital Inclusion
DYNAMIC RESOURCE MANAGEMENT
FOR DOWNLINK MULTIMEDIA
TRAFFIC IN OFDMA CELLULAR
NETWORKS
Dhananjay Kumar
Anna University, Chennai, India
Email: dhananjay@annauniv.edu
Mar del Plata, Argentina, 31 Aug – 1 Sep 2009
Presentation Outlines
Multimedia Services
Multi Carrier Systems
OFDMA System Model
Problem Formulation
Two Stage Rate Adaptive (TSRA)
Algorithm
Bandwidth Adaptive (BWA) algorithm
Results & Discussions
Mar del Plata, Argentina, 31 Aug – 1 Sep 2009
ITU-T Kaleidoscope 2009 – Innovations for Digital Inclusion
2
Mobile Multimedia Services
Multimedia over Mobile Network
Text
Images
Video
Audio
QoS Support
Dynamic & Efficient Resource
Requirements
Mar del Plata, Argentina, 31 Aug – 1 Sep 2009
ITU-T Kaleidoscope 2009 – Innovations for Digital Inclusion
3
MPEG-4 video trace (Die Hard III)
Frame
Size
Frame Index
Mar del Plata, Argentina, 31 Aug – 1 Sep 2009
ITU-T Kaleidoscope 2009 – Innovations for Digital Inclusion
Courtesy: Technical University, Berlin :
http://www.tkn.tuberlin.de/research/trace/ltvt.html
Trace File of Some Hollywood Movie
Frame Size
Quality
High
Jurassic Park I
Compression
Mean
Cov Peak/ Mean Mean
Peak
Ratio
YUV:MP4 X [kbyte] σ2/X
Xmax/X^ X/t[Mbps] Xmax/t[Mbps]
9.92
3.8
0.59
4.37
0.77
3.3
Silence of the Lambs
13.22
2.9
0.80
7.73
0.58
4.4
Star Wars IV
27.62
1.4
0.66
6.81
0.28
1.9
Jurassic Park I
28.4
1.3
0.84
6.36
0.27
1.7
Silence of the Lambs
43.43
0.88
1.21
13.6
0.18
2.4
Star Wars IV
97.83
0.39
1.17
12.1
0.08
0.94
Jurassic Park I
49.46
0.77
1.39
10.61
0.15
1.6
Silence of the Lambs
72.01
0.53
1.66
21.39
0.11
2.3
Star Wars IV
142.52
0.27
1.68
17.57
0.053
0.94
Medium
Low
Trace
Bit Rate
Mar del Plata, Argentina, 31 Aug – 1 Sep 2009
ITU-T Kaleidoscope 2009 – Innovations for Digital Inclusion
Courtesy: Technical University, Berlin :
http://www.tkn.tuberlin.de/research/trace/pub.html
5
MPEG-4 Advanced Audio Coding
Audio quality
CD like Quality
(BW>15 KHz)
ULD
80 kbps
AAC-ELD
64 kbps
Wide Band
(BW 7 KHz)
Narrow
Band
(BW 3.5 KHz)
AAC-LD
64 kbps
AAC-LC
56 kbps
AAC-ELD
32 kbps
MP3
64 kbps
HE-AAC
20 kbps
Speech
codec
(Speech)
Telephone
codec
Speech
codec
(Music)
10
AAC: Advanced Audio Coding
ULD: Ultra-Low-Delay
AAC-ELD: Enhanced Low Delay AAC
AAC-LD: Low Delay AAC
20
30
40
50
Algorithmic delay in ms
Mar del Plata, Argentina, 31 Aug – 1 Sep 2009
ITU-T Kaleidoscope 2009 – Innovations for Digital Inclusion
100
130
AAC-LC: Low Complexity AAC
HE-AAC: High-Efficiency AAC
Courtsey: Fraunhofer IIS
Service classification and service
parameters
User Experience
Class
Guidelines for
evaluation of
radio interface
technologies
for IMTAdvanced
Conversational
Streaming
Interactive
Service Class
Basic conversational
service
Rich conversational
service
Conversational
low delay
Streaming Live
Throughput:
Delay:
Throughput:
Delay:
Throughput:
Delay:
Throughput:
20 kbit/s
50 ms
5 Mbit/s
20 ms
150 kbit/s
10 ms
2 – 50 Mbit/s
Streaming Non-Live
Delay:
Throughput:
100 ms
2 – 50 Mbit/s
Delay:
Throughput:
Delay:
Throughput
Delay
Throughput:
1s
500 kbit/s
200 ms
500 kbit/s
20 ms
5 – 50 Mbit/s
Delay:
< 2s
Interactive high delay
Interactive low delay
Source: Document
8F/TEMP/568
Background
Service Parameters
(Numerical Values)
Background
Mar del Plata, Argentina, 31 Aug – 1 Sep 2009
ITU-T Kaleidoscope 2009 – Innovations for Digital Inclusion
7
Multi-Carrier Communication in
Next Generation Networks
Higher Capacity
Can approach theoretical limit
Easy support for adaptive
resource Allocation
The Concept of Sub
Channel/Carrier
Ability to combat inherent
problems in wireless
Mar del Plata, Argentina, 31 Aug – 1 Sep 2009
ITU-T Kaleidoscope 2009 – Innovations for Digital Inclusion
Multi Path Propagation
Diffraction
Reflection
Line of sight
Scattering
Reflection
Mar del Plata, Argentina, 31 Aug – 1 Sep 2009
ITU-T Kaleidoscope 2009 – Innovations for Digital Inclusion
Channel Response in Freq. Domain
|H(f)|
f
Mar del Plata, Argentina, 31 Aug – 1 Sep 2009
ITU-T Kaleidoscope 2009 – Innovations for Digital Inclusion
The Concept of Multi-carrier
P
o
w
e
r
Frequency
BS
P
o
w
e
r
Mar del Plata, Argentina, 31 Aug – 1 Sep 2009
ITU-T Kaleidoscope 2009 – Innovations for Digital Inclusion
Frequency
Multi-Carrier Communication Systems
MC-CDMA
Suitable for indoor wireless environment
Fading resistance using frequency
diversity
Need for rake receivers
OFDMA
Handling of multipath fading (ISI)
Spectral efficiency
No intra-cell interference (No Cell
breathing)
Mar del Plata, Argentina, 31 Aug – 1 Sep 2009
ITU-T Kaleidoscope 2009 – Innovations for Digital Inclusion
OFDMA System Model
User
1
2
N
Subcarrier 1
Sub carrier
and bit
allocation
scheme
(M-QAM)
Subcarrier 2
Subcarrier N
IFFT and
parallel
to serial
Allocation
information
Symbos
to bit
mapping
Su
carrier
selector
Add
cyclic
prefix
Wireless
channel
to user k
FFT and
serial to
parallel
Mar del Plata, Argentina, 31 Aug – 1 Sep 2009
ITU-T Kaleidoscope 2009 – Innovations for Digital Inclusion
Remove
cyclic
prefix
Problem Formulation
Initial subcarrier allocation:
k
N ink = Φ ( N min
,α k )
αk is chosen such that 0 ≤ αk < 1 while
satisfying the condition
∑α
k
= 1, ∀k
k
To calculate Nmin , we first compute BER of
the sub channel. The BER of ith subcarrier using
M-QAM can be approximated by.
1 ⎛ 1.5SINRi ⎞
⎟⎟
BER = exp⎜⎜ −
5 ⎝ M −1 ⎠
i
Mar del Plata, Argentina, 31 Aug – 1 Sep 2009
ITU-T Kaleidoscope 2009 – Innovations for Digital Inclusion
Problem Formulation cont.
The order of modulation M for the ith sub carrier is
chosen such that the BER < 10-3.
In M-QAM the maximum capacity could be
approximated by
R
i
sb
B
=
log 2 M
N
If Rk is the minimum bit rate needed to
support an application k, and Risb is the bit rate
supported on the ith sub carrier, then the
minimum no of required sub carrier is given by
k
N min
Mar del Plata, Argentina, 31 Aug – 1 Sep 2009
ITU-T Kaleidoscope 2009 – Innovations for Digital Inclusion
⎡
⎤
⎢ R ⎥
= ⎢ Nk k ⎥
⎢
i ⎥
R
⎢ ∑ sb ⎥
⎢ i =1
⎥
Problem Formulation cont.
Considering L types of applications,
the sub carrier selection can be defined
as optimization of
L
Kl
Nk
∑ ∑ ∑α
i
l ,k
p (CINR )
i
l ,k
i
l ,k
l =1 k =1 i =1
such that average capacity (bits/second per Hz), Cav
represented below is maximum.
L
Kl
Nk
Cav = ∑∑∑
l =1 k =1 i =1
Mar del Plata, Argentina, 31 Aug – 1 Sep 2009
ITU-T Kaleidoscope 2009 – Innovations for Digital Inclusion
Rli,k
N k ( BW ) sb
16
Development of TSRA Protocol
Packet/
Time
unit
Rth2
Rth1
Time Units
Mar del Plata, Argentina, 31 Aug – 1 Sep 2009
ITU-T Kaleidoscope 2009 – Innovations for Digital Inclusion
17
START
The BWA
Algorithm
Initialize Rth1, Rth2, Ri
Monitor the change in input
data rate (ΔRi) in every tmin
duration
A
Yes
Is ΔRi is small
No
Is Ri
centered
around Rth1
or Rth2
No
A
Wait for
tmin. Is
ΔRi>rth?
Yes
Vary the modulation
order to meet the
requirements
If Ri changes
from Rth1 to
Rth2
No
Yes
Yes
A
If Ri
fluctuates
Rth1≤Ri≤Rth2
No
A
Wait for
tmin. Ri at
Rth2?
No
Yes
Yes
Is call
disconnected?
No
A
No
Wait for
tmin. Ri at
Rth1?
Yes
Allocate from nrt-VBR
& ABR till
Rti = Ri+Riac
Assign Mean Value
Rti= (Rt1+ Rt2)/2
If Ri changes
from Rth2 to
Rth1
Yes
Yes
Wait for
tmin. Same
status ?
Mar del Plata, Argentina, 31 Aug – 1 Sep 2009
ITU-T Kaleidoscope 2009 – Innovations for Digital Inclusion
No
Starts de-allocation &
share among ABR &
nrt-VBR
No
Yes
END
18
Average Capacity
7
Analytical
TSRA with BWA
TSRA without BWA
Average Capacity (bit/s/Hz)
6
5
4
3
2
1
2
4
6
8
10
Number of Users
Mar del Plata, Argentina, 31 Aug – 1 Sep 2009
ITU-T Kaleidoscope 2009 – Innovations for Digital Inclusion
12
14
16
19
Throughput per OFDM Symbol
1.4
TSRA with BWA and AM
TSRA without BWA and AM
TSRA with BWA without AM
Throughput (Mbps) per OFDM Symbol
1.3
1.2
1.1
1
0.9
0.8
0.7
2
4
6
8
10
Number of Users
Mar del Plata, Argentina, 31 Aug – 1 Sep 2009
ITU-T Kaleidoscope 2009 – Innovations for Digital Inclusion
12
14
16
20
Average delay for rt-VBR traffic
0.06
Average Delay (Seconds)
0.05
0.04
0.03
0.02
0.01
0
2
4
6
8
10
Number of Users
Mar del Plata, Argentina, 31 Aug – 1 Sep 2009
ITU-T Kaleidoscope 2009 – Innovations for Digital Inclusion
12
14
16
21
Average BER
-3
4.5
x 10
4
Average BER
3.5
3
2.5
2
1.5
1
0.5
2
4
6
8
10
Number of Users
Mar del Plata, Argentina, 31 Aug – 1 Sep 2009
ITU-T Kaleidoscope 2009 – Innovations for Digital Inclusion
12
14
16
22
CONCLUSION
Multi-carrier can support future
multimedia services
The 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)
Mar del Plata, Argentina, 31 Aug – 1 Sep 2009
ITU-T Kaleidoscope 2009 – Innovations for Digital Inclusion
23
Thank You Very Much
Mar del Plata, Argentina, 31 Aug – 1 Sep 2009
ITU-T Kaleidoscope 2009 – Innovations for Digital Inclusion
24