A CONTROL FRAMEWORK FOR ADAPTIVE
CAPACITY ALLOCATION IN MOBILE DVB-RCS
JA-2330 Integration Meeting
Nedo Celandroni*, Franco Davoli°, Erina Ferro*,
Alberto Gotta*, Raffaello Secchi*
*ISTI-CNR, Area della Ricerca del C.N.R., Via Moruzzi 1,
I-56124 Pisa, Italy
°DIST-University of Genoa and CNIT (Italian National
Consortium for Telecommunications), Italy
Pisa – Nov. 8th 2007
JA2330 Integration Meeting
Istituto di Scienza e Tecnologie
dell’Informazione “A Faedo”
MUltimedia MObile Bandwidth
ALlocation (MUMOBAL) architecture
•
Class-based Dynamic Bandwidth Allocation
–
•
One portion of bandwidth for each typology of traffic and moving boundaries between
bandwidth portions
In each portion, the Network Control Centre (NCC) assigns bandwidth to the relevant
traffic classes, by taking into account their QoS requirements and traffic characteristics
•Collision
•Collision free
free Optimal
Optimal controller:
controller:
•• Optimal
DBA
Control
Optimal DBA Control Algorithm
Algorithm
for
Service
Level
Agreement
for Service Level Agreement
•Collision
•Collision free
free DAMA:
DAMA:
•• Rate
Rate Based
Based Dynamic
Dynamic Capacity
Capacity
•• Volume
Volume Based
Based Dynamic
Dynamic Capacity
Capacity
•• FCA
FCA option
option
•Contention
•Contention access
access DSA:
DSA:
•• Contention-based
Contention-based MAC
MAC
Collision free
Optimal Controller
Collision free
Optimal Controller
Pisa – Nov. 8th 2007
•EF
•EF traffic:
traffic:
•• Voice,
Voice, video
video &
& Real
Real Time
Time
applications
applications with
with QoS
QoS requirements
requirements
•Large
•Large volume
volume AF
AF &
& BE
BE traffic:
traffic:
•• web
web applications,
applications, video
video streaming,
streaming,
interactive
interactive and
and peer-to-peer,
peer-to-peer, etc...
etc...
•Small
•Small volume
volume BE
BE traffic:
traffic:
•• web-browsing,
web-browsing, e-mail,
e-mail, signaling,
signaling, etc…
etc…
Collision free
DAMA
Collision free
DAMA
Contention access
DSA
Contention access
DSA
JA2330 Integration Meeting
Istituto di Scienza e Tecnologie
dell’Informazione “A Faedo”
Report of recent activities
• Simulation of LMS channel model (ESA) at packet
level and derivation a packet level model
• Evaluation of performance of error
techniques to counteract lossy periods
correction
• Comparison of different access techniques
– Random Access: Diversity Slotted Aloha
– Deterministic Access: Demand Assignment Multiple Access
• Trade-off between bandwidth cost and completion
time as concerns TCP performance
Pisa – Nov. 8th 2007
JA2330 Integration Meeting
Istituto di Scienza e Tecnologie
dell’Informazione “A Faedo”
DVB-RCS/S2 for mobile users
Simulation (Matlab/Simulink) of DVB-RCS/S2 chain with ESA
channel model
In each channel state (LoS, Shadowed, Blocked)
Average Packet Error Rate
Average Burst Error Length
Traces
Based on simulation results, we derived a mobile channel
description at packet level
3-state Discrete Markov Chain 2-state Discrete Markov Chain
(ON-OFF)
Pisa – Nov. 8th 2007
JA2330 Integration Meeting
Istituto di Scienza e Tecnologie
dell’Informazione “A Faedo”
DVB-RCS for mobile users (uplink)
PER (DVB packets)
•
•
•
Mobile channel in LoS
is substantially
different from AWGN
Significant differences
in PER between LoS
and Shadow states
Minor differences
(less than 1 dB) in
PER for each state in
different environments
Ec/N0
Pisa – Nov. 8th 2007
JA2330 Integration Meeting
Istituto di Scienza e Tecnologie
dell’Informazione “A Faedo”
DVB-S2 for mobile users (downlink)
PER (LDPC blocks)
•
•
•
PER curves very
steep in LoS
environment
Significant
differences in PER
between LoS and
Shadow states
PER curves
strongly dependent
from modcod
Ec/N0
Pisa – Nov. 8th 2007
JA2330 Integration Meeting
Istituto di Scienza e Tecnologie
dell’Informazione “A Faedo”
Case study: mobile user acts as an FTP client
LMS channel parameters
TDMA/DSA
DOWNLINK: TDM
UPLINK:
ON/OFF
mobile
channel
TNB
TBL
Blocking
prob.
Highway
3.02 s
0.36 s
0.107
Rural
2.03 s
0.55 s
0.215
Environment
HUB station
SERVER
Terrestrial
Segment (50 ms)
CLIENT
Internet
Gateway
RTT=600 ms, Segment size=1416B (equivalent to 8
DVB packets), Frame size=20 ms, TCP/Sack
Pisa – Nov. 8th 2007
JA2330 Integration Meeting
Istituto di Scienza e Tecnologie
dell’Informazione “A Faedo”
Short-lived connections (highway)
Average Uplink Bandwidth Cost
700
DSA 10%
DSA 20%
TDMA 1f/s
TDMA 2f/s
TDMA 4f/s
TDMA 8f/s
500
400
12
C o m p le tio n T im e [s ]
D V B p a c k e ts /c o n n e c tio n
600
Average Completion Time
14
300
200
10
8
DSA 10%
DSA 20%
TDMA 1f/s
TDMA 2f/s
TDMA 4f/s
TDMA 8f/s
6
4
100
2
0
0
20
40
60
80
0
Connection Length [kB]
Pisa – Nov. 8th 2007
20
40
60
80
Connection Length [kB]
JA2330 Integration Meeting
Istituto di Scienza e Tecnologie
dell’Informazione “A Faedo”
Long-lived connections (highway)
45000
40000
35000
30000
25000
20000
15000
10000
5000
0
1600
1400
DSA
TDMA
DSA
1200
TDMA
1000
800
600
400
200
0
10% 20%
•
Completion Time
d u ra tio n [s ]
D V B p a c k e ts /c o n n e c tio n
Bandwidth Cost
1 f/s 2 f/s 4 f/s 8 f/s
10% 20%
1 f/s 2 f/s 4 f/s 8 f/s
DSA may not be suitable for long-lived connections in highway
–
DSA 10% is outperformed by DAMA 1f/s in both duration and cost, while
DSA 20% has a duration very close to DAMA 4f/s, but the latter exhibits
a significantly lower cost
Pisa – Nov. 8th 2007
JA2330 Integration Meeting
Istituto di Scienza e Tecnologie
dell’Informazione “A Faedo”
Considerations on DAMA/DSA
comparison
1. The smaller the size of file transfer, the higher the gain in terms of
bandwidth and connection duration of DSA with respect to DAMA
in bandwidth expenditure
2. DSA cost depends on data successfully delivered only, thus it is
less sensible to changes in the channel blocking probability
3. DSA is not convenient for long-lived connections in both
environments (limited to our investigations)
•
The choice of system parameters is a matter of more complex
investigations (e.g. the mobile acts as server). Nevertheless, once
the parameters have been selected, cost diagrams will be used to
evaluate convenience thresholds. For instance
– In case DAMA 4f/s and DSA10% are selected as the most
convenient options, the threshold file size is about 17 kB and 65 kB
for highway and rural environments, respectively
Pisa – Nov. 8th 2007
JA2330 Integration Meeting
Istituto di Scienza e Tecnologie
dell’Informazione “A Faedo”
Main objectives
• MUMOBAL objective is to design an MFTDMA access scheme based on DVB-S2
(RCS) suitable to support various classes
of users (fixed, large and small mobile)
with different classes of traffic (streaming,
TCP, etc.)
Pisa – Nov. 8th 2007
JA2330 Integration Meeting
Istituto di Scienza e Tecnologie
dell’Informazione “A Faedo”
Future plans
• Analysis of the case in which the mobile user acts as a
server:
– Operating the choice of the target throughput in DSA and the
minimum assignment in DAMA
• For the server case, in order to obviate to the collisions’
effect in DSA, a packet level FEC might be necessary
• Completion of the analysis of the application of PLFEC
and inter-leaver to streaming traffic (DVB-S2 and RCS)
• Review of the DAMA design to optimize a TCP
connection in a mobile environment
• Extension of the Ka-band paper to a journal version
Pisa – Nov. 8th 2007
JA2330 Integration Meeting
Istituto di Scienza e Tecnologie
dell’Informazione “A Faedo”