Transcript ppt - 無線寬頻網路實驗室

IPTV STB and
QoS/QoE
Speaker：林裕強
Date：2010/11/5
OUTLINE

IPTV introduce

IPTV STB introduce

STB technique

QoS/QoE
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Conclusion

Reference
2
IPTV introduce

由於以IP為基礎的寬頻網路發展迅速，網路
承載能力不斷提高，因此，為了能夠提升IP
網路業務，促進IP網路普及與發展，將數位
電視的豐富媒體資源引入IP網路中，而
IPTV就是在IP網路與傳統電視業務融合產
生的新的業務。主要特點在於交互性和即
時性。
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IPTV introduce
Fig ：IPTV 架構圖
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IPTV introduce
Fig: IPTV deployment topology and available delivery
schemes
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IPTV STB Overview

Set-Top Box (STB)是在很廣泛的産品名詞，
在中文譯爲視訊轉換器、機頂盒或機上盒，
其代表的功能則從過去的類比選台器、電
視上網機，一路發展下來，目前的STB已
可以涵蓋家庭閘道器或個人視訊錄
放影機(PVR)的産品定位。
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IPTV STB Overview
IPTV用戶端負責接收、處理、儲存、播放
、轉發數據文件、EPG….等。
 IPTV終端有三種基本類型:PC、手機、STB+電視。
 STB須具備包括數據轉換、接入支持(FTTH、
XDSL、HFC…等)、業務支持、解碼支持、協議
支持、DRM、內容緩存等功能。
 Entry-level digital set-top box、Mid-range
digital set-top box、High-range digital settop box

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IPTV STB Overview

IP STB的功能定位示意圖
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IPTV STB technique requirement

業務能力要求
IPTV機頂盒需要支持基本業務和擴展業務
功能。
基本業務包括直播、點播、時移電視。
擴展業務包括可視業務、網路遊戲、訊息
交換
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IPTV STB technique requirement

功能要求
STB設備在IPTV中需要實現承上啟下的作
用，一方面接收業務系統的媒體串流，另
一方面要實現對用戶業務播放過程的控制。
STB作為業務網路用戶接入設備，須有一
系列的管理功能:管理功能、通訊協議、業
務功能。在STB標準僅對媒體處理、交互
功能、管理功能、安全和環境做具體規範。
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IPTV STB technique requirement

(1).媒體處理功能要求
需支持基本業務和擴展業務所需媒體處理 功能。基本業
務可在MPEG-2、 MPEG-4、H.264、SMPTE，音頻解碼
採用MPEG-2/4 AAC(Advanced Audio Coding) 、MP3、
Dolby AC 3/5.1。
擴展業務需支持CIF(Common Intermediate Format )、
QCIF(Quater Common Intermediate Format)、H.261、
H.263，音頻以G.711為標準，亦可採G.723、G.728、
G.729為標準
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IPTV STB technique requirement

(2).交互功能要求
STB需提供內容交互選擇和內容交互控制
兩類交互功能。內容交互選擇利用選單選
擇內容，進行節目檢索與認證系統交互認
證訊息。內容交互控制主要針對實現點播
業務時，機頂盒與業務平台間應具有交互
控制命令，以控制內容訊息功能。
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IPTV STB technique requirement

(3).管理功能要求
a.軟體升級:透過本地網路或是連至外部網路下載
安裝最新套件以獲取新業務的能力
b.日記功能:針對本機版本訊息及系統訊息的管理
與錯誤訊息的診斷，並產生兩份備份文件。
c.遠端配置功能:重新啟動、下載、恢復設定等。
d.本地配置功能:遙控器對STB訊息配置、網入連
接帳號密碼等
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IPTV STB technique requirement

外部接入要求
-外部接口基本須包含三類:網路、音視訊及紅外線
遙控接口，根據需要還可擴展。
-網路接口:包括10/100Base-T、xDSL、無線接口
-音視訊接口:類比、數位音訊、視訊接口
-紅外線遙控接口:規定紅外線遙控器對機頂盒控制
傳輸距離、紅外線發射角度和接收最小角度，具
體性能要求應符合IrDA1.1(Infrared Data
Association)協議
-輔助接口:USB
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IPTV STB technique requirement
通信協議要求
IPTV STB為網路接入的終端設備，必須支
援一系列的業務與IP，機頂盒標準將所涉及
IP歸納為:
接入過程:PPPoE、DHCP、IEEE802.1x
文件傳送:TFTP、FTP、HTTP
媒體傳送:RTP、RTSP
媒體播放:IGMP

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IPTV STB technique requirement

安全要求
-安全認證要求:STB需支持AAA(Authentication,
Authorization, and Accounting )，接入IP網路
應提供必要的訊息，經認證授權後才可使用IPTV
業務
-數位版權(DRM)管理安全要求:供應商送到用戶終
端的訊息應具有DRM的訊息，在STB中須有針對
業務平台的DRM版本，提供內容版權的保護。
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IPTV STB 功能結構
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因為IPTV STB 提供三網融合的業務，做到triple
play，可以建立IP化的家庭環境。
目前可支援IPTV產品大致分為: Entry-level
digital set-top box、Mid-range digital set-top
box、High-range digital set-top box。
STB由軟硬體所構成，硬體包含CPU、Storage、
Feedback Channel 、Conditional Access、
external device。
軟體則有操作、解譯與應用三大方面。
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IPTV STB硬體結構
Fig :STB系統架構圖
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IPTV STB軟體結構


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(1)嵌入式WinCE終端
優:支援Windows 套件。
缺:原始碼不公開、WinCE佔用許多ROM
RAM
(2)嵌入式Linux終端
優:原始碼公開、技術交流方便、維護成本低。
缺:解碼器性能需芯片支援。
(3)other software : Ex VxWorks
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STB設備分類與功能定位
Entry-level digital set-top box
接受數位廣播電視為主要功能，並具有按次計費
(pay-per-view, PPV)的系統功能與基本的瀏覽工
具，這類設備的特色包括低成本，以及有限的記
憶容量、輸出入介面及運算能力。
 Mid-range digital set-top
具有回傳的管道，因此能提供與系統業者在頭端
(head-end)的伺服器進行溝通，此外，不論在處
理效能或儲存能力上都比入門級數位STB還強上
一倍以上。

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STB設備分類與功能定位

High-range digital set-top box
功能更強，幾可比擬多媒體桌上型電腦，它的運算能力
可以是低階廣播電視STB的十倍以上，例如在儲存能力上
一般有 32-64Mbyte的Flash記憶容量，也有高速的回傳
管道來提供多種進階服務，此外，它的繪圖功能也很強，
能讓收視戶收看高畫質電視訊號。
在高階STB的市場上，又有多種不同的功能定位，例如
有些高階設備更提供了個人錄影機(Personal Video
Recorder,PVR)的功能，也就是在STB中置入硬碟，讓
STB有足夠的儲存容量錄製節目。不僅如此，新的IP STB
設備還具有家庭網路的連接埠，讓STB進一步成為家用閘
道器(Residential Gateway)。
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STB與IPTV接口
STB與IPTV平台接口，包含網路層認證與
應用層認證，按照目前用戶與網路間的通
訊方式，分為以下三種。
(1)認證接口:PPPoE與DHCP+WEB驗證。
(2)用戶消費接口:依照系統價格提示、用戶
確認購買，系統實現扣費的一個消費流程。
(3)服務使用接口:實現用戶從內容營運商獲
得不同應用服務的過程。

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DVB-IPTV: Functional model
HNED: Home Network End
DNG:
Content Providers
SD&S:
Service Provider N
Service Provider 2
Service ProviderLive
1 Broadcast
CoD
Live Broadcast
Live Broadcast
CoD
CDS
BCG
CoD
BCG
SD&S server
BCG
SD&S server Service inf.
Service inf.
BCG:
CoD:
CDS:
---
SD&S server
Service inf.
Focus of DVB-IPTV
specification
SD&S server
Service provider inf.
Time
server
Device
Delivery Network
Gateway
Service Discovery and
Selection
Broadband Content Guide
Content on Demand
Content Download
Service
indicates optional entity
IPI-3
IPI-4
Delivery Network
(Access & Core)
Firmware Update
Remote Management
DHCP
NAT
DNG
DHCP
Home
Network
IPI-1
HNED
DNS
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DVB-IPTV: Service Provider Discovery
HNED contacts SD&S entry point(s) for
service provider information
 Entry point lookup (in order):
•DNS service location lookup for
_dvbservdsc._tcp/udp.<domain name>
Content Providers
•Well known address 224.023.14
(DVBServDisc)
•DNS service location lookup for
Service Provider N _dvbservdsc._tcp/udp.services.dvb.org
Service Provider 2
•Manual entry of URL
Service ProviderLive
1 Broadcast
CoD  SD&S server provides Service Provider
Live Broadcast
CoD
Discovery record(s):
Live Broadcast
CoD
•Service provider name
SD&S server
BCG
•Description
SD&S server Service inf.
BCG
•Domain Name
SD&S server Service inf.
CDS
BCG
•Offerings
Service inf.
•Address (push and/or pull)
•Type of information
SD&S server
Service provider inf.
Time
server
IPI-3
IPI-4
Delivery Network
(Access & Core)
Firmware Update
Remote Management
DHCP
NAT
DNG
DHCP
Home
Network
IPI-1
HNED
DNS
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
DVB-IPTV: Service Discovery
SD&S info delivered
either in multicast
(DVBSTP) or in unicast
(HTTP)
 Id. of a Service Provider:
Content Providers
• Domain name
 Id. of a live service:
• DVB triplet and
• Textual service identifier
 ID of a Broadband Content
Guide
Service Provider N
Service Provider 2
Service ProviderLive
1 Broadcast
CoD
Live Broadcast
Live Broadcast
CoD
CDS
BCG
CoD
BCG
SD&S server
BCG
SD&S server Service inf.
Service inf.
SD&S server
Service inf.
SD&S server
Service provider inf.
Time
server
IPI-3
IPI-4
Delivery Network
(Access & Core)
Firmware Update
Remote Management
DHCP
NAT
DNG
DHCP
Home
Network
IPI-1
HNED
DNS
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DVB-IPTV: Service selection and consumption for streaming
 Service selection
•Unicast: RTSP
•Multicast IGMPv3(+
optional RTSP); ASM and
SSM supported
 Streaming:
•RTP/RTCP (+ optional ALFEC or RET)
•UDP
Content Providers
Service Provider N
Service Provider 2
Service ProviderLive
1 Broadcast
CoD
Live Broadcast
Live Broadcast
CoD
CDS
BCG
CoD
BCG
SD&S server
BCG
SD&S server Service inf.
Service inf.
SD&S server
Service inf.
SD&S server
Service provider inf.
Time
server
IPI-3
IPI-4
Delivery Network
(Access & Core)
Firmware Update
Remote Management
DHCP
NAT
DNG
DHCP
Home
Network
IPI-1
HNED
DNS
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DVB-IPTV: Service selection and consumption for download
 Service selection
•Download Session
Descriptions
•Unicast: http
•Multicast IGMPv3
 Download:
•Multicast: FLUTE (+
optional FEC)
•Unicast: http
•File Repair procedures
Content Providers
Service Provider N
Service Provider 2
Service ProviderLive
1 Broadcast
CoD
Live Broadcast
Live Broadcast
CoD
CDS
BCG
CoD
BCG
SD&S server
BCG
SD&S server Service inf.
Service inf.
SD&S server
Service inf.
SD&S server
Service provider inf.
Time
server
IPI-3
IPI-4
Delivery Network
(Access & Core)
Firmware Update
Remote Management
DHCP
NAT
DNG
DHCP
Home
Network
IPI-1
HNED
DNS
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QoS/QoE

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Quality of service is the ability to provide
different priority to different applications,
users, or data flows, or to guarantee a certain
level of performance to a data flow.
IPTV streaming technology considers the
possible service transfer from wire to
wireless/from wireless to wire that is in place
to ensure quality of service/quality of
experience (QoS/QoE).
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Factors that affect the iptv


Network delay
Delay manifests itself in a number of ways,
including the time taken to establish a
particular service from the initial user
request and the time to receive specific
information once the service is established.
Delay has a very direct impact on user
satisfaction depending on the application,
and includes delays in the terminal, network,
and any servers.
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Factors that affect the iptv
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
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Network delay variation (Jitter)
Delay variation is generally included as a
performance parameter since it is very
important at the transport layer in packetized
data systems due to the inherent variability
in arrival times of individual packets.
Services that are highly intolerant of delay
variation will usually take steps to remove (or
at least significantly reduce) the delay
variation by means of buffering, effectively
eliminating delay variation as perceived at
the user level.
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Factors that affect the iptv
Packet Loss
 Packet loss has a very direct effect on
the quality of service finally presented
to the user, whether it be voice, image,
video or data.

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QoE(Quality of Experience )


QoE is the term which is used to describe
how it is satisfied by subscribers to the
provided service quality. The poor QoE will
cause dissatisfied subscribers and fall
behind in contestants due to the ultimately
bad market competitive power to contestants.
QoE is composed of not only the network
performance parameter but also the service
quality parameter such as cost, reliability,
availability, usability, and fidelity.
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QoE scale
Fig . Example alternative qualitative scales that may be
derived from data collected on a quantitative scale.
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QOS/QOE CORRELATION MODEL FOR
IPTV QOE EVALUATION


IPTV providers need a method to control QoE
when QoE is not satisfied by subscribers.
Network providers can evaluate subscriber's
QoE using QoS parameters weight and some
analyzed values which is from the proposed
model, and control QoE as deduce QoS
parameters(delay, loss, jitter etc) associated
with QoE.
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QOS/QOE CORRELATION MODEL FOR IPTV
QOE EVALUATION
Fig . QoS/QoE Correlation Model for IPTV
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QOS/QOE CORRELATION MODEL FOR IPTV
QOE EVALUATION
K :means the whole QoS quality determinant which is selected
according to the type of the access network for the IPTV service.
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QOS/QOE CORRELATION MODEL FOR IPTV
QOE EVALUATION
Qr: a coefficient limiting the range of the IPTV image QoE
according to the display size and/or resolution of the
terminal.
A: expresses the subscribed service class
R : determined as the constant reflecting the structure of
the video frames according to the GoP(Group of Picture)
length
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EXAMPLE OF THE IPTV VIDEO QOE EVALUATION
USING THE QOS/QOE CORRELATION MODEL
Case 1: MPEG-4 HDTV service
• Packet Loss = 2.78E-06 (W1=8E+04)
• Burst Level = 1.67ms (Wu=lO)
• Packet Jitter = 37ms (Wj=O)
• Packet Delay = 105ms (Wd=0.5)
• Bandwidth = 8Mbps (Wb=2.0E-1O)
• GoP Length = 12, Qr = 5

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EXAMPLE OF THE IPTV VIDEO QOE EVALUATION
USING THE QOS/QOE CORRELATION MODEL
Case 2: MPEG-4 SDTV service
• Packet Loss = 2.78E-06 (Wl=1.5E+04)
• Burst Level = 1.67ms (Wu=20)
• Packet Jitter = 37ms (Wj=O)
• Packet Delay = 105ms (Wd=0.5)
• Bandwidth = 8Mbps (Wb=O)
• GoP Length = 12, Qr = 4.5

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EXAMPLE OF THE IPTV VIDEO QOE EVALUATION
USING THE QOS/QOE CORRELATION MODEL
Fig: QoS Parameter Weights of IPTV Service In HDTV Class
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EXAMPLE OF THE IPTV VIDEO QOE EVALUATION
USING THE QOS/QOE CORRELATION MODEL
Fig: QoS Parameter Weights of IPTV Service In SDTV Class
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Result

HDTV
QoS(X) = 0.27817 QoEv = 2.94617
Fig: Case_1 : HDTV Class
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Result
SDTV
 QoS(X) = 0.09754 QoEv = 4.24475

Fig: Case_2 : SDTV Class
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Conclusion

Network providers can predict subscriber's
QoE in provided network environment and
analogize service environment which meet
the optimum QoE on the contrary.

Network operator can prevent the
unnecessary investment for the enlargement,
maintenance and repair of the network.
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Reference
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[1]李偉, 等. IPTV關鍵技術與應用, 2007 , 7.
[2] H. L. Kim, S. G. Choi, “A Study on a QoS/QoE
Correlation Model for QoE Evaluation on IPTV Service,”
Feb. 2010.
[3] ITU-T P.800, "Mean Opinion Score (MOS)
terminology," Mar. 2003.
[4] ITU-T P.861, "Objective quality measurement of
telephone-band (3003400Hz) speech codec," Feb. 1998
[5] ITU-T P.910, "Subjective video quality assessment
methods for multimedia applications," Sep. 1999.
[6] ITU-T Recommendation Y.1541, "Network
performance objectives for IP-based service," Feb. 2006.
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圖片來源:NTT Cyber Solutions
Laboratory
Figure . IPTV coverage
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