1 mpeg streaming over mobile internet kyunghee lee and myungchul kim {leekhe, mckim}@icu.ac.kr
TRANSCRIPT
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MPEG Streaming over Mobile Internet
Kyunghee Lee and Myungchul Kim
{leekhe, mckim}@icu.ac.kr
2
Contents• Introduction
• Related Work
• Proposed Mechanism
• System Design
• Testbed Configuration
• Experiments
• Performance Evaluation
• Conclusions
• References
3
Introduction• General multimedia data characteristics
– Intolerant to delay and jitter variance
– Error-sensitive
• Characteristics of mobile Internet– Frequent routing path changes due to handoffs
– Higher error rate in wireless link
• Effects on streaming multimedia data in mobile Internet– Handoff delay
– Re-routing toward congested network delay increment
– Higher packet loss probability due to mobility
Significant quality degradation of streaming multimedia data
4
Introduction (cont’d)
• Popular Quality of Service (QoS) guarantee mechanisms
– Differentiated Service (DiffServ) [2]• Guarantees aggregated QoS for multiple flows• Can not guarantee specific QoS requirement for each data flow
– Integrated Service (IntServ)• Network resource reservation for specific data flow• Strict guarantees for multimedia streams with various QoS
requirements• Resource Reservation Protocol (RSVP) [3]
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Introduction (cont’d)
• Problems of RSVP in Mobile Internet– Mobile Host (MH) handoff invalidates existing reservation paths
overhead and delay to re-establish new RSVP session
– Movement to congested wireless cell fail to get admission to re-establish new RSVP session
Seamless QoS guarantees are impossible
• Existing approaches– Mobile RSVP (MRSVP) [15]
– Hierarchical Mobile RSVP (HMRSVP) [16]
– A method of Concatenation and Optimization of Reservation Path (CORP) [10]
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Related Work• Priority-based scheduling for MPEG streaming on
Mobile Internet– Differentiated delivery service depending on the
importance of each MPEG frame data
R1
FA
CH
I
B
B
P
I
BP B
I
P
Priority-awarePriority-awareMPEG ServerMPEG Server
MHMH
: : MPEG video streamMPEG video stream
: : Non-multimedia TrafficNon-multimedia Traffic
Packet dropPacket drop
MPEG ClientMPEG Client
congestedcongested
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Related Work (cont’d)
• Classify IP packets into two classes depending on its payload– Class 1: containing MPEG and GOP header (priority 1)
– Class 2: containing MPEG I frame (priority 1)
– Class 3: containing MPEG B, P frame (priority 7, best-effort)
• Uses TOS field in IP packet header as a classifier
….
4-4-bitbitversionversion
4-4-bitbitheader len.header len.
8-bit TOS field 16-16-bit total length (in bytes)bit total length (in bytes)
16-16-bit identificationbit identification 3-3-bit flagbit flag 13-13-bit fragment offsetbit fragment offset
8-8-bit time-to-live (TTL)bit time-to-live (TTL) 8-8-bit protocolbit protocol 16-16-bit header checksumbit header checksum
32-32-bit source IP addressbit source IP address
00 1616 3131
3-bit precedence field(currently ignored)
minimizedelay
maximizethroughput
maximizereliability
minimizemonetary
cost
1-bitunused
4 TOS bits
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Related Work (cont’d)
• Priority-aware MPEG streaming server
MPEGvideo file
Analysis Packetization
Priority setting
MPEGvideo client
UDP
Priority-aware MPEG video stream server
Parse theMPEG file
make an offsettable
move MPEG datafrom a file to the buffer
check up the data inthe buffer set the TOS
value of thepacket
decide the value ofTOS field
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Related Work (cont’d)
• Mobile IP Foreign Agent (FA)– Is the most probable spot of packet loss due to the network
congestion– Acts as a gateway router for its own wireless subnet– Runs mobile IP FA daemon program– Performs priority-based CBQ scheduling for the traffic delivered
toward MH
• Mobile MPEG client– Plays MPEG video stream from the server
• Advantages
– Simple and light-weight mechanism suitable for wireless/mobile
networking environment
– Significant video quality improvement can be achieved though the
extra bandwidth is scarcely consumed
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Related Work (cont’d)
• Testbed configuration
Non-diffserv routerNon-diffserv routerR
HA FA
MH
BackgroundBackgroundtraffictraffic
Priority-awarePriority-awareMPEG serverMPEG server
MPEG video streamMPEG video stream
Priority-based scheduling on/offPriority-based scheduling on/off
WirelessWirelesssubnet 1subnet 1
WirelessWirelesssubnet 2subnet 2
Experiment scenarioSample MPEG file specification
Background traffic pattern
File size 1.2 Mbytes
Playing outDuration 48 sec
Frame rate 30 fps
Avg. bit rate
214 Kbps
ContainingFrames
102 I, 404 P, 1010 B
* * Total Total 1516 frames 1516 frames
****The bandwidth limit in the WaveLAN II The bandwidth limit in the WaveLAN II wireless link: wireless link: 5.07 Mbps5.07 Mbps
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Related Work (cont’d)
• Experimental results– Number of the received packets (at client) containing either
MPEG header or I-frame (Class 1, 2)• Each packet size: 1024 bytes• Total number of Class 1 or 2 packets: 151• Number of the received packets: 151 (the proposed mechanism), 121
(FIFO scheduling)
– Transfer rate variation of the MPEG video stream
• Transfer rate is more independent on the amount of the background traffic
( ) Class 1, 2 packets are served by the priority-based scheduling
80000
100000
120000
140000
160000
180000
200000
1 5 9 13 17 21 25 29 33 37 41 45 (sec)
(bp
s)
FIFO scheduling priority-based CBQ scheduling
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Related Work (cont’d)
• Experimental results (cont’d)– PSNR value distribution
• Amount of the received traffic: 824 Kbytes (FIFO), 852 Kbytes (CBQ) out of total 1.2 Mbytes
• Number of frames 20 dB: 919 (FIFO), 775 (CBQ)• Number of frames with 78 dB: 151 (FIFO), 192 (CBQ)• 78 dB: same quality with the original image 20 dB: impossible to be recognized by human eyes
0
50
100
150
200
250
300
350
400
450
10 20 30 40 50 60 70 78
PSNR (dB)
Num
ber
of fr
am
es
FIFO scheduling Priority-based CBQ scheduling
Out of total1440
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Related Work (cont’d)
• CORP– Base Station (BS) takes charge of making and managing
RSVP sessions on behalf of MH– Consists of two main processes
• Concatenation of Reservation Path (CRP) process– Reservation path extension technique– Current BS pre-establishes pseudo reservation path (PRP) toward its
neighboring BSs to prepare for MH’s handoff – When MH handoffs, corresponding PRP is activated to guarantee QoS
for MH
• Optimization for Reservation Path (ORP) process– Solves infinitely long path extension problem and reservation
path loop problem of CRP process– Optimizes the extended reservation path
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Related Work (cont’d)
• CRP Process
BS_CBS_BBS_A
I. MH requests a new RSVP session and BS_B makes it on behalf of the MH
II. BS_B sends CRP inform messages to its neighbors
CRP inform
CRP inform
CORP message
RSVP session
PRP
Activated PRP
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Related Work (cont’d)
• CRP Process
BS_CBS_BBS_A
I. MH requests a new RSVP session and BS_B makes it on behalf of the MH
II. BS_B sends CRP inform messages to its neighbors
III. BS_B makes PRP to its neighbors
CORP message
RSVP session
PRP
Activated PRP
16
Related Work (cont’d)
• CRP Process
BS_CBS_BBS_A
I. MH requests a new RSVP session and BS_B makes it on behalf of the MH
II. BS_B sends CRP inform messages to its neighbors
III. BS_B makes PRP to its neighbors
IV. MH handoffs toward BS_C’s cell
CORP message
RSVP session
PRP
Activated PRP
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Related Work (cont’d)
• CRP Process
BS_CBS_BBS_A
I. MH requests a new RSVP session and BS_B makes it on behalf of the MH
II. BS_B sends CRP inform messages to its neighbors
III. BS_B makes PRP to its neighbors
IV. MH handoffs toward BS_C’s cellCRPactivate
V. BS_C sends CRP activate message to the previous BS (BS_B)
CORP message
RSVP session
PRP
Activated PRP
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Related Work (cont’d)
CRP Process
BS_CBS_BBS_A
I. MH requests a new RSVP session and BS_B makes it on behalf of the MH
II. BS_B sends CRP inform messages to its neighbors
III. BS_B makes PRP to its neighbors
IV. MH handoffs toward BS_C’s cell
V. BS_C sends CRP activate message to the previous BS (BS_B)
VI. BS_B forwards MPEG-1 video through the activated PRP
CORP message
RSVP session
PRP
Activated PRP
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Related Work (cont’d)
CRP Process
BS_CBS_BBS_A
I. MH requests a new RSVP session and BS_B makes it on behalf of the MH
II. BS_B sends CRP inform messages to its neighbors
III. BS_B makes PRP to its neighbors
IV. MH handoffs toward BS_C’s cell
V. BS_C sends CRP activate message to the previous BS (BS_B)
VI. BS_B forwards MPEG-1 video through the activated PRP
VII. BS_B terminates useless PRP toward BS_A
CORP message
RSVP session
PRP
Activated PRP
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Related Work (cont’d)
• ORP Process
BS_CBS_BBS_A
CORP message
RSVP session
PRP
Activated PRP
I. BS_C sends IGMP group report message to its gateway router
IGMPreport
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Related Work (cont’d)
ORP Process
BS_CBS_BBS_A
CORP message
RSVP session
PRP
Activated PRP
I. BS_C sends IGMP group report message to its gateway router
II. BS_C joins into the existing multicast RSVP session
CRPrelease
III. BS_C sends CRP release message to the previous BS (BS_B)
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Related Work (cont’d)
ORP Process
BS_CBS_BBS_A
CORP message
RSVP session
PRP
Activated PRP
I. BS_C sends IGMP group report message to its gateway router
II. BS_C joins into the existing multicast RSVP session
III. BS_C sends CRP release message to the previous BS (BS_B)
IV. BS_B terminates the activated PRP and BS_C uses the newly optimized one to deliver MPEG data stream to MH
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Related Work (cont’d)
ORP Process
BS_CBS_BBS_A
CORP message
RSVP session
PRP
Activated PRP
I. BS_C sends IGMP group report message to its gateway router
II. BS_C joins into the existing multicast RSVP session
III. BS_C sends CRP release message to the previous BS (BS_B)
IV. BS_B terminates the activated PRP and BS_C uses the newly optimized one to deliver MPEG data stream to MH
V. BS_B leaves the multicast RSVP session
CRPinform
CRPinform
VI. BS_C sends CRP inform messages to its neighbors to prepare MH’s probable movement
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Proposed Mechanism
• Motivation– To provide QoS guarantees for MPEG video streaming services
with mobility support
• Proposed System– Uses CORP to guarantee seamless QoS in mobile networks
– Provides MPEG-1 video streaming services over CORP
– CORP-aware video streaming server and client
– CORP-capable mobile agents (Base Stations)
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System Design
• Video Server Architecture– CORP adaptation module
handles CORP messages and takes charge of resource reservation process
– MPEG-1 traffic transfer module transfers MPEG-1 stream to BS at the speed of a reserved bandwidth
Video Server
RSVP
TCP/UDP
IP
Wired Link
CORP AdaptationModule
MPEG-1 TrafficTransfer Module
CORP message
MPEG-1 data
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System Design (cont’d)
• Base Station Architecture– CORP message handler
module handles CORP messages which are generated by neighboring BSs or a mobile client
– traffic forward module receives MPEG-1 streaming data from the video server and forwards it to a neighboring BS or directly delivers it to the client
CORP
RSVP
TCP/UDP
IP/Mobile IP
Wired/Wireless Link
CORP MessageHandler Module
TrafficForward Module
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System Design (cont’d)
• Client Architecture– CORP adaptation module
handles CORP messages– Handoff detection module
detects a handoff and determines when MH has to request the activation of PRP
– MPEG-1 traffic receiver module receives MPEG-1 streaming data from a current BS
– MPEG-1 video playback module plays the MPEG-1 video from the received stream
Client
TCP/UDP
Mobile IP
Wireless Link
CORP AdaptationModule
MPEG-1 TrafficReceiver Module
Handoff DetectionModule
MPEG-1 VideoPlayback Module
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System Design (cont’d)
• MPEG-1 Service Procedure over CORP before Handoff
Video Server BS1 ClientBS2
Service Request
Service Request Ack
Service Request
Service Request Ack
RSVP path
RSVP resv
MPEG-1 trafficMPEG-1 traffic
PRP establishment
ClientHandoffs
(BS1BS2)
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System Design (cont’d)
• MPEG-1 Service Procedure over CORP after Handoff
Video Server BS1 ClientBS2Client
handoffs
CRP Activate RequestCRP Activate
CRP Activate Ack
MPEG-1 traffic MPEG-1 traffic MPEG-1 traffic
ORP Request
ORP Request Ack
RSVP path
RSVP resv
MPEG-1 trafficMPEG-1 traffic
(BS1BS2)
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Testbed Configuration• Network Architecture
Wired subnet bandwidth10 Mbps Ethernet
Wireless subnet bandwidthIEEE 802.11b wireless LAN with the bandwidth of 11 Mbps
BSRuns FA daemon of Mobile IP
Runs CORP daemon
ClientRuns MH daemon of Mobile IP
Runs VOD client program
Video ServerSupports CORP-aware MPEG-1 streaming service
MH
BS2
Gateway
BS1
Video Server
Wireless Subnet_1
Wireless Subnet_2
Wired Subnet_1 Wired Subnet_2
Home Agent
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Experiments• Experiment Scenarios
– Background traffic generation: MGEN– Maximum throughput of wired network:
9.34 Mbps– Wired subnet_1: non-congested– Wired subnet_2: congested
• 8.2 Mbps background traffic– Movement of MH: BS1 BS2
• Experiment CasesI. MPEG-1 streaming with CORP and TCPII. MPEG-1 streaming with TCP onlyIII. MPEG-1 streaming with CORP and UDPIV. MPEG-1 streaming with UDP only
Shrek
Resolution 352 X 288
Average Data Rate (Mbps)
1.39
Frame Rate (fps) 25
Play out duration (sec)
80
Total number of frames
2,000
Sample Video Clip Specification
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Performance Evaluation• QoS Guarantee
– Data rate is measured at client per each second while the sample MPEG file is being delivered
– Not much difference in data rate distribution between before and after handoff cases in (I)
– Amount of packet loss due to handoff is about 81Kbytes in (I)– 84 percents are less than 0.3 Mbps after handoff in(II)
I. MPEG-1 Streaming with CORP and TCP II. MPEG-1 Streaming with TCP only
0
10
20
30
40
50
60
70
80
0 0.3 0.6 0.9 1.2 1.5 1.8 2.1 2.4 2.7 3
Data receiving rate per each second (Mbps)
Pe
rce
nta
ge
(%
)
Before HandoffAfter Handoff
0
10
20
30
40
50
60
0 0.3 0.6 0.9 1.2 1.5 1.8 2.1 2.4 2.7 3
Data receiving rate per each second (Mbps)
Per
cent
age
(%)
Before Handoff
After Handoff
* 150KBps bandwidth reserved
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Performance Evaluation (cont’d)
• QoS Guarantee (cont’d)
– Not much difference in data rate distribution between before and after handoff cases in (I)
– Average data rate before handoff is significantly higher than that after handoff in (II)
– Average packet loss rate is about 0.6 Mbps in (II)
0
10
20
30
40
50
60
70
80
90
100
1 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 1.9 2
Data receiving rate per each second (Mbps)
Pe
rce
nta
ge
(%
)
Before HandoffAfter Handoff
0
10
20
30
40
50
60
70
80
90
100
0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2
Data receiving rate per each second (Mbps)
Pe
rce
nta
ge
(%
)
Before HandoffAfter Handoff
I. MPEG-1 Streaming with CORP and UDP II. MPEG-1 Streaming with UDP only
* 200KBps bandwidth reserved
34
Performance Evaluation (cont’d)
• Quality of Streaming Video
– If Peak Signal to Noise Ratio (PSNR) is less than 20 dB, the frame can be regarded as being lost
– In (I), MPEG-1 streaming data did not suffer from loss or delay under the congested situation
– 11 frames were lost during CRP process time in (I)– the total number of received frames is only 1107 frames out of 2000
frames for 80 seconds in (II)
0
10
20
30
40
50
60
70
80
90
0 200 400 600 800 1000 1200 1400 1600 1800 2000
Frame number
PS
NR
(dB
)
Handoff0
10
20
30
40
50
60
70
80
90
0 200 400 600 800 1000 1200 1400 1600 1800 2000
Frame number
PS
NR
(dB
)
Handoff
I. MPEG-1 Streaming with CORP and TCP II. MPEG-1 Streaming with TCP only
35
Performance Evaluation (cont’d)
• Quality of Streaming Video (cont’d)
– The average PSNR is 69.6 dB before MH’s handoff and 68.6 dB after MH’s handoff in (I)
– MH could not play back MPEG-1 video stream correctly after handoff in (II) because of too high packet loss rate (0.6 Mbps)
0
10
20
30
40
50
60
70
80
90
0 200 400 600 800 1000 1200 1400 1600 1800 2000
Frame number
PS
NR
(dB
)
Handoff0
10
20
30
40
50
60
70
80
90
0 200 400 600 800 1000 1200 1400 1600 1800 2000
Frame number
PS
NR
(dB
)
Handoff
I. MPEG-1 Streaming with CORP and UDP II. MPEG-1 Streaming with UDP only
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Conclusions• QoS guarantee for MPEG-1 streaming service in Mobile
Internet– QoS guarantee mechanism with mobility support – CORP– Implementation of MPEG-1 streaming service over CORP
• Streaming Video Quality Improvement– Significantly better PSNR values in both cases of using TCP and UDP
when CORP mechanism is applied– MPEG-1 streaming with CORP and TCP provided the highest video
quality in the experiments
• Future work– Reduction in the packet loss during a handoff with CORP– Reduction in the packet loss over wireless links when UDP is used as
a transport protocol