A Comprehensive Study of IPTV: Challenges, Opportunities, and Future Trends

1. Introduction

Internet Protocol Television (IPTV) is an online television service in which audio and video services are transmitted through a high-speed Internet network and arrive directly to the home user. Video or audio data are sent over a network in the form of packets which can be received by the home user on a home computer or a special decoder box (set-top box) [1,2].

IPTV is still in its early stages of development throughout the world, since it requires a very high-speed internet connection, such as broadband or ADSL to deal with the enormous amount of data which has to be received in order to view television broadcasts without any significant data loss [2,3].

One of the main challenges for operators of an IPTV service is to ensure Quality of Service which at least matches the present Quality of Service which presently exists for digital television operators of terrestrial (such as Free-view), satellite (such as Sky) and cable (such as Virgin media) television services [3,4].

To complicate matters, there is very little standardization of IPTV protocols and the many consumers may be reluctant to commit them, at this early stage, since some encoder boxes may soon become obsolete as new standards of service become more available. Encoder boxes will initially be very operator dependent and is unlikely to be useful when a consumer decides to switch to a different operator of an IPTV service [5,6].

IPTV services are likely to increase significantly in the coming years as they offer a number of advantages over current television. IPTV offers flexibility such as more interactive TV which is not fully possible with existing TV material broadcasters. One main attraction of IPTV over present TV broadcasters is the offer of triple play or quad play service which involves voice over IP, television and internet and mobile services. IPTV can also target consumers who do not currently have access to cable or satellite TV or may not have their own PC, but have access to broadband services [2,7].

Some television broadcast companies see IPTV as a threat to their services, but they also recognize that this may be a good opportunity to expand their services. These companies are actively involved in the development of an IPTV service for customers as an extension to their own present service. IPTV, however, is unlikely to completely replace existing television broadcast media since there are still enormous challenges to be met in producing a good Quality of Service for IPTV. There are many issues to be considered, and many regulations have to be agreed upon by various worldwide organizations. Some of these issues are discussed in this paper [8,9].

2. Attractions and Challenges of IPTV

IPTV is in its infancy and faces many challenges before becoming an acceptable television media which competes with present television broadcasters such as Sky TV, Virgin Media, and Free-view. In addition to the technical challenges, there are a number of issues regarding the ownership and rights of broadcasting programs in the UK [3,4]. Programs are bought and sold years in advance of transmission, and IPTV will not be in a position for a number of years to offer the same quality of programs without considerable cost to the operator. Technical challenges are a big issue with the limited bandwidth of existing broadband connections. IPTV operators will be expected to offer HDTV quality programs in order to compete with Television broadcasting companies. A single HDTV broadcast on an IPTV system can consume the entire bandwidth of an existing broadband connection. However, this is likely to be less of a problem in future years as technology is constantly advancing with better compression techniques and higher-bandwidth broadband connections. Optical cable networks directly to the home user are likely to be a requirement for IPTV quality of service, but this may prove to be expensive for most customers [5,6].

Interactive TV is a big attraction for IPTV services and is likely to appeal to a large audience particularly those involved with the gaming industry. This in itself is a challenge, since standardization cannot be guaranteed between different operators. Several organizations are actively involved in trying to bring some standardization to future IPTV services, but this will take some time since this is a rapidly developing service [10]. In the long term, IPTV may have cost benefits for the end user, particularly for those users who require triple-play services and interactivity [2,7,8].

3. IPTV TV Channel Throughput

In the UK, a standard SDTV channel has a resolution of $720\times 576$. For a $4:2:2$ profiles, the data volume is reduced by $33\%$ in comparison with a $4:4:4$ RGB profile.

Since each of the 3 color bytes for each pixel is 8 bits long, the transmission rate required to transmit a color picture at 25 frames per second is given by the formula:

$$\mathrm{SDTV} \mathrm{Transmission} \mathrm{rate} =720\times 576\times 8\times 3\times 25\times 2/3=166\mathrm{MBit}/\sec .$$

In the case of HDTV with a resolution of $1920\times 1080$, the transmission rate is given by:

$$\mathrm{HDTV} \mathrm{Transmission} \mathrm{rate} =1920\times 1080\times 8\times 3\times 50\times 2/3=1.66\mathrm{GBit}/\sec .$$

Video compression techniques, which record changes in each frame (such as MPEG-2) generally have compression ratios up to 100. SDTV and HDTV transmission rates are therefore within the MPEG-2 Bit Rate range of $2-20\mathrm{Mb}/\mathrm{s}$. HDTV MPEG-2 compression Bit Rate operates in the range $10-20\mathrm{Mbit}/\sec$. Lower bit rates, by a factor of 2, are possible with more efficient compression techniques such as MPEG-4 [11,12].

As demonstrated above, HDTV requires a high-bandwidth broadband line which is about feasible on existing UK $10\mathrm{MHz}$ broadband lines. However, higher speed lines will be required for good quality triple-play services [5,9,10].

4. Protocol

One of the advantages of IPTV transmission is that common video material can be transmitted to large groups of people using IP multicasting. In order to reduce bandwidth, an IPTV operator will need to transmit the same programs to a number of people. To make this possible, an IGMP protocol (Internet Management Group Protocol) has been set up to achieve this goal. This protocol also allows an authorized user to join a new multicast group [11,12]. Therefore, only the watched channel must be transmitted along the broadband line. Quality of Service is an important part of multicast transmission in that the controller adjusts the protocol to include more error-correcting techniques to guarantee acceptable television viewing, as shown in Figure 1 below.

For streaming live video data, an RTSP (Real-Time Video Streaming Protocol) has been developed, which is suitable for IPTV transmission. This protocol offers DVD player control of video on demand such as pause, play, and stop. With HDTV becoming more popular, there is a need to reduce the transmission bandwidth on IPTV services using more advanced compression techniques. A promising protocol is $\mathrm{H}.264$ (MPEG-4) which is more efficient than MPEG-2, which is likely to deliver good Quality of Service to the customer and reduce costs to the operator [13,14,15].

4.1. Triple Play and Quadruple Play

One of the strengths of an IPTV service is that it can offer voice on demand, television, and internet access (Triple Play) as part of a service, as shown in Figure 2 below. This is likely to reduce costs for the customer if the end user requires all three types of service. An extension to a mobile wireless service is also possible from an IPTV service in that data or text messaging can be sent to a mobile device (Quadruple Play) [1,2,16].

4.2. Difference of IPTV and Internet TV (Closed and Open Networks)

There are a number of differences between IPTV and Internet TV. One of the main differences is that IPTV is a service which is supplied by an operator which offers a closed-loop system entirely under its own control, similar to present day cable operators. This offers the benefit of security and non-theft of material and includes quality of service (QoS), which is not subject to breakdowns in network service or network overload. Presently Internet TV is an open network, which does not guarantee Quality of Service and is prone to traffic flow problems when the network becomes overloaded. The video quality is usually low quality due to bandwidth problems and can suffer a temporary loss of signal during the heavy use of a local network [17]. Internet TV is also a PC based system which is not secure and requires the user to provide their own security measures to avoid attacks on their system [18].

An IPTV service is essentially a direct line to a local operator in which the user is a known customer of the operator through specified IP addresses and a set-top box. This is not the case with Internet TV since the user can access the Internet through various channels and conceal their identity. Video formats are also different on an IPTV system which usually uses MPEG compression techniques [16]. Since IPTV is a closed network system, some people argue that competition from open-loop systems is the biggest threat to operators, rather than competition from other IPTV operators [11]. The quality of service can only be guaranteed on a closed system that is fully controlled by the service provider [11,12].

4.3. Is High Definition TV (HDTV) Likely to Make Any Difference

HDTV is becoming increasingly popular with television audiences in this country and is expected to be watched by the majority of the population within the next $10-20$ years [7]. Transmission of HDTV channels consumes large bandwidths and is likely to be a problem for multiple channel transmission by Satellite and Terrestrial Broadcasters in the future. The problem is that there are a limited number of frequency bands available for transmission over the airways. Cable and IPTV operators may benefit from this by offering more bandwidth in the future to accommodate HDTV channels. Live TV sports channels and the gaming industry are likely to influence the demand for HDTV services [9]. The personal video recording of HDTV channels is likely to be in demand from customers who cannot watch live broadcasts. This consumes a large bandwidth on an IPTV service network and is currently one of the main challenges for a service provider [5,6,10].

4.3.1. YouTube

Video streaming over the public Internet viewed on a PC (e.g., MySpace, YouTube, etc.) has been available for some time but at low quality resolution. One big difference with IPTV is that YouTube users can upload or delete their own video which has been already uploaded. The data stream runs only for a limited amount of time [14]. In the IPTV system, there is a continuous video stream, which never stops playing. No user can delete or upload material because the system is under full control of the operator. YouTube is unlikely to be a threat to the IPTV industry, but will continue to be a popular source of low-quality video for mobile users, etc [17,19,20].

4.3.2. IPTV Security

IPTV security can be an important attraction for the customer. ID theft is a particular concern for many people and IPTV may be one way to solve this problem. IPTV is entirely controlled by the operator and is likely to offer banking services without security risk. Children’s television programs and adult material can also be controlled using security pin numbers [14]. Parent control of children’s habits can become an attraction for parents who are concerned about the material on the Internet. IPTV is likely to become more involved in Internet access to weed out suspicious Web site viewing. Virus checkers, spyware, and pop-up software are likely to be provided by the IPTV service to maximize security [16]. Service theft is one area where IPTV will be actively involved in stopping customers passing on their material to other non-IPTV users. The set-top boxes already have built-in encryption software, but hackers will continue to be a problem for the operator [15,18].

5. Current IPTV Offerings

Worldwide, IPTV services are already available in a number of countries, including the UK [19]. France, China, and the United States are the leading players in this field, where many millions of customers have already signed up for their services. Many European countries such as Italy, Denmark, and Belgium have been running and testing IPTV services to offer customers a wide range of options to view large amounts of material at their leisure [20]. The UK has been slow to start to take advantage in this field and is due in part to the slow broadband channel speeds currently available in this country compared to foreign countries [2].

In order to attract customers, BT Vision, Homechoice (now merged with Tiscali), and KITV are already offering a number of basic TV channels, such as BBC, ITV, Channel 4, Microsoft IPTV, Apple IPTV are also involved in producing IPTV services [3,4]. BT Vision has its own network infrastructure and set-top box. Microsoft has plans to cooperate with BT Vision in bringing gaming and entertainment to the IPTV system. To improve Internet security, such as banking, there is no reason why part of the Internet service can be channeled through the IPTV service provider as a closed system. However, most customers would likely prefer that the internet provision is left as an open system [2,17].

6. Conclusion-Discussion

IPTV is set to become the next revolution in the TV industry from the point of view of flexibility, interactivity, and the number of services that can be offered. However, it is unlikely to replace existing television broadcasting and is more likely to be part of an overall television service [3,19].

The younger generation is likely to be the main driving force behind the demand for IPTV services, since they have a better understanding of what modern technology can offer based on their experience of PC and mobile phone technology [2,17].

Some customers know that IPTV is a service in which the operator has direct access to your viewing and shopping habits and may be put off by the amount of control the operator may have. This may be seen as another case of ’big brother’ [2]. There is also a view that IPTV may be seen as a way of charging for access to the world wide Web [14].

Internet advertising is likely to play an important role in an IPTV service in generating revenue for the operator. Users can be targeted with selective advertisements based on their viewing habits. Competitions against other users can be arranged, which is likely to be popular and offer a great deal of scope for novel ideas [6,10].

IPTV Video conferencing is likely to be attractive to business leaders from their home locations and offices. Chat rooms can be organized in which individuals can have face-to-face discussions [18].