IPTV on the Rise

Download as PDF

Abstract—In the recent past, evolutionary applications have started to emerge, augmenting or replacing the common and often superannuated entertainment services that find everyday use. IPTV, or, providing television programming over the packetswitched Internet has been one of them; a service expecting to prostrate the simple TV broadcast, and enhance its features, using novel sets of applications, offered within the same infrastructure. This article overviews the IPTV service, analyzing its key-features as a technology, as well as the unique demands they pose. At the same time, it illuminates the wired and wireless network architectures that can facilitate IPTV service delivery, while addressing cost, reliability, and quality of service requirements. Finally, it also discusses of the IPTV issues and research areas that can further help the strong founding of the IPTV service.

I. INTRODUCTION TO IPTV
IPTV stands for Internet Protocol Television and a common misconception regarding it, is that it is considered simply a different method of delivering digital video services using the Internet Protocol (IP) instead of traditional air, cable or satellite broadcasting. Yet, IPTV is a lot more than that. IPTV can indeed offer audiovisual content using Internet as a medium, but it does so providing two features that traditional TV broadcasting has failed to offer; personalization and interactivity. These interlinked characteristics are evident in the services that IPTV thrives to support. The IPTV programs allow the viewing audience to individuate the screened video content by adjusting and controlling the cameras and its angles. At the same time, and mostly applicable to sports, it is possible for the viewer to retrieve real-time statistics of the game, such as player performance or tournament history. Furthermore, IPTV defines entertainment interactivity by offering the audience the ability of real-time participation in certain shows. As added features, IPTV provides digital video recording (DVR) and video on demand (VoD). The former function allows capturing the video content for later use, as well as pausing, fast forwarding and rewinding not only the recoded but also the currently playing (live) multimedia content, in conjunction with the commodity of recording multiple channels simultaneously. VoD permits a customer to browse through an online program or film catalogue, and upon request to watch trailers and to then select a specific content for playback. As such, the audience has the ability retain a multimedia content repository adjusting what they can view according to their varying desires.

A. Underlying Technology
To offer these features, IPTV relies on specific technologies. To start with, packet-switched networks are limited in terms of their throughput and level of quality of service. Subsequently, the IPTV platform has to maintain a minimum size content, and has to be deployed on network infrastructures that can guarantee its problem free content delivery.
In order to decrease the multimedia content size, media encoding and compression mechanisms are used. The standardization body MPEG handles video content as moving pictures, and compresses the content by exploiting redundancy between pictures. Several encoding standards have been released, for instance MPEG-1, MPEG-2, H.264 and VC1, providing various video resolutions and audio qualities. These algorithms have successfully lowered the bit rates of the multimedia content delivered, while maintaining a good, or even high video quality.
Yet, even with the highest compression algorithms, TV video content cannot be broadcasted in a unicast fashion to every viewer, in the same way it is broadcasted now in continuous availability. This would consume the available bandwidth of a network and would leave little margin to be used for other activities, such as web-browsing, VoIP calls etc. To alleviate this, multicast addressing scheme is utilized. Multicast is a bandwidth-conserving technology able to simultaneously deliver a single stream of data to multiple users [1], without needing to send the same copy of data on the same network path. The interest of a certain group of users to subscribe to the IPTV multicast material is expressed via the IGMP protocol, whereas the protocol that is utilized for the actual transfer of the content is -usually- UDP, as the retransmission feature of TCP is highly inappropriate for a video sequence.
The whole process from media encoding and compression, to forming IGMP groups, multicast forwarding trees within the network, routing protocols utilization and the decoding of the content on the audiences’ premisses illuminates the fact that IPTV traffic is highly inelastic prone to delays, that incorporates several techniques and mechanisms that need to function perfectly so as to deliver a prospected content quality. At the same time, minor network problems including packet loss or reordering can cause severe artifacts on the audiovisual stream, making it harder for IPTV to compete with traditional TV broadcasting.

II. IPTV ISSUES AND RESEARCH AREAS
IPTV technology and despite the recent global economic crisis, is still on the rise. The number of subscribers is growing, together with the service providers that offer it [2]. Yet, it should be noted that the mass deployment of IPTV is still refrained, mainly due to the reasons that are going to be described hereafter.

A. Standardization
An unanswered IPTV issue is standardization; something that would enable cross-platform portability and uniform user interface, allowing faster IPTV proliferation and improving at the same time user friendliness, which otherwise evokes strangeness and unfamiliarity to the users as described in [3]. While there is no unique established standard for IPTV, significant efforts have been made by various bodies:

• Digital Video Broadcasting (DVB) over IP networks [4] provides a set of technical specifications that cover the delivery of DVB MPEG-2-based services over IP-based networks. The key technologies specified are the service discovery and selection (SDS) mechanism for MPEG- 2 transport over IP and the DVB Real-Time Streaming Protocol client (RTSP).
• The ITU-T Focus Group (FG) IPTV [5] coordinates the development of global IPTV standards taking into account the existing work of the ITU-T Study Groups. As such, it has recently established the IPTV-GSI (Global Standards Initiative) working group to harmonize standards on a global level.
• Telecoms and Internet converged Services and Protocols for Advanced Networks (TISPAN) [6] is the standards group within ETSI which addresses several specifications regarding IPTV architecture. TISPAN defines the functional architecture and reference points of a customer network device for both IP multimedia subsystem (IMS)- based and non-IMS-based IPTV services.
• The Alliance for Telecommunications Industry Solutions (ATIS) [7] initiated the IPTV Interoperability Forum (IIF) that develops standards and specifications to enable the interoperability, interconnection, and implementation of IPTV systems and services, including VoD and interactive TV services.
• The Third Generation Partnership Project (3GPP) specifies Multimedia Broadcast/Multicast Service (MBMS) specifications mainly to define an efficient way to deliver and control multicast and broadcast innovative services over 3G networks [8].
• Finally, 3GPP has defined IP Multimedia Subsystem (IMS), a Services Initiation Protocol (SIP)-based control framework. IPTV networks and systems can be easily integrated into an IMS service delivery scheme and operate under this control infrastructure allowing it to function on all kinds of devices.

A single standard could unleash the full potential of IPTV, enabling delivery of TV-based entertainment from any source, including broadcast, on-demand and open Internet ’Over-the- Top’ (OTT) services.

B. Evolution Issues
The IPTV service is not remaining static. User demands, network technology breakthroughs, problems and limitations modify its proliferation and shape its evolution. To start with, current user expectations are more demanding than ever. IPTV viewers require more High Definition (HD) programs, multichannel audio, improved electronic program guides (EPGs), and tend to make increased usage of VoD services as well as interactive features such as voting and gaming. At the same time, IPTV is a service prospected to function in all types of devices, from wired stationary computers to mobile smartphone devices. As such, the proper network architectures should be developed that account for the IP-convergence, allowing IPTV content to be easily delivered across multiple and different type devices in continuous availability and high quality. These demands mandate the migration to different network architectures. Ideal choices for wired IPTV accessnetworks would be architectures that makes use of fiber-optic communications such as FTTH (Fiber-To-The-Home), where the fiber optics reach up to the customers premisses, FTTB (Fiber-To-The-Building) where they terminate before reaching each apartment and Fiber-To-The-Cabinet (FTTC) where the fibers are run to a cabinet serving an area approximately 1500m in radius. Fiber-optics networks can offer a higher bandwidth allocation than any other technology while ensuring top level of quality of service for the IPTV inelastic traffic. Another type of network that can support the IPTV audience demands is Very high bitrate Digital Subscriber line (VDSL). VDSL makes use of the twisted pair cables that are already installed for the public switched telephone network with specified profiles that cover a range of applications including up to 100 Mbps symmetric transmission. VDSL has incorporated techniques specifically targeting IPTV traffic delivery, including Impulse Noise Protection (INP), a capability which can correct impulse noises and dual latency, which provides improved QoS features by enabling simultaneous transport of applications with different physical layer requirements, features that are mandatory for realizing the IPTV viewers’ demands. In wireless communications, a high capacity broadband wireless technology with a theoretical coverage radius reaching 50 Km and a data rate of up to 75 Mbit/s that is capable in handling IPTV data is Worldwide Interoperability for Microwave Access - WiMAX. WiMAX as seen from its characteristics has features required to support the inelastic video of IPTV and, even more importantly, it can provide IPTV services to mobile stations [9]. IPTV proliferation is also progressing due to multicast support on 4G networks, which allows it to support video services deployment. By using innovative patents such as [10], any TV viewer on the 4G network can view live high definition TV and video on demand in full HD 1080p with surround sound without any buffering or jerkiness.
The growth of IPTV subscribers number will allow the service providers to increase their revenue, yet, it will also emerge drawbacks. Large number of users will appoint the IPTV service prone to security threats, since there is a higher possibility of users that might attempt to obtain unauthorized access to the service, resulting in content theft, and excessive congestion that will lead to denial of service (DoS) of legitimate subscribers. Furthermore, the unauthorized access can enable the illegitimate users to copy, redistribute or even alter the streamed multimedia content, something that is in direct violation of the Digital Rights Management (DRM), eventually causing the reluctance of content distributors to cooperate with the unreliable telecom operators.

III. CONCLUSION
This article overviews the IPTV service, including its characteristics and features, while discussing open issues that are possibly refraining its market proliferation. As network architectures are advancing and open issues are being addressed, the IPTV service platform is becoming a new way of home entertainment, prostrating traditional applications. Based on the innovative set of offerings, IPTV is on continuous rise and there is little doubt that it will soon change the way video content is delivered and consumed by the viewing audience.

REFERENCES
[1] Beau Williamson, “Developing IP Multicast Networks,” Cisco Press,
2000.
[2] Multimedia Research Group - MRG Inc., “IPTV Global Forecast: 2010
to 2014 (June 2010),” Report, jun 2010.
[3] Insook Kim and Jongdeok Kim, “A Study on factors providing
strangeness in IPTV,” IASDR Proceedings, jun 2009.
[4] ETSI TS 102 034 V1.2.1 tech. spec., “DVB; Transport of MPEG 2
Based DVB Services over IP-Based Networks,” sept 2006.
[5] ITU-T FOCUS GROUP ON IPTV, wkg. doc. IPTV-DOC-0084, “IPTV
Architecture,” 4th FG IPTV mtg., Bled, Slovenia, 2007.
[6] ETSI ES 282 001 V1.1.1, TISPAN, “NGN Functional Architecture
Release 1,” 2005.
[7] ATIS IPTV High Level Architecture Standard (ATIS-0800007), “ATIS
IPTV Interoperability Forum (IIF),” 2007.
[8] 3GPP TS 23.246 V8.0.0, tech. spec., “Multimedia Broadcast/Multicast
Service (MBMS); Architecture and Functional Description,” rel. 8, sept
2007.
[9] J. She, F. Hou, P. Ho, and L. Xie, “IPTV over WiMAX key success
factors, challenges, and solutions,” IEEE Communications Magazine,
vol. 45, no. 8, pp. 87–93, aug 2007.
[10] MatrixStream Technologies Inc., “Solution: IPTV Over 4G
LTE/WiMAX Wireless Network,” Productsheet.