Many researchers have discussed EPG design and implementation in the IPTV systems. This section presents a brief explanation of the IPTV system and its structure as an introduction to discuss the EPG within IPTV systems.
An IPTV system is a digital television service that is delivered over a dedicated provider network using an IP networking protocol. This system works on a TV with a supplementary device called a set-top-box which accesses channels and other multimedia content through a broadband connection which connects to the provider’s network. It is different from Internet TV or Internet video streaming. Hence it is a secure, subscription service, local (limited operator coverage), that provides an end-to-end operator managed
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service which guarantees the quality of service (QoS) over the provider’s network. However, IPTV providers may also include Internet services such as Web access and Voice over IP (VoIP) in which case the become known as Triple Play.
The typical architecture of IPTV service comprises: a Super Head-End, Core Network, Access Network, Regional Head-End and Customer Premises. The Super Head-End encodes and processes the channels and transmits them to the Regional Head-End through the provider’s core network allowing it to serve millions of subscribers across their serving area. The Regional Head-End handles local programming, delivering channels to a single city or geographic area. Programmes are then transmitted as data streams to the subscriber’s premises through a range of access networks including Cable and Digital Subscriber Line (DSL) (Martinsson, 2006; Punchihewa, De Silva, & Diao, 2010). Figure 2.5 illustrates a simple structure of the main functional parts of an IPTV system.
IPTV services could be classified into four domains which are the consumer domain, network provider domain, service provider domain and content provider domain. The consumer domain presents the services to the end user while the network provider domain permits the connection between the consumer and service provider domain. The service provider domain is responsible for providing services for all subscribers whilst the content provider domain possesses licenses to sell or distribute the content. Currently, IPTV provides subscribers with linear TV programmes in the same way as traditional through the air broadcasters. However, many also supplement this with additional services including video on demand (VoD), personal video recorder (PVR), EPG and a traffic and weather service (Zeadally, Moustafa, & Siddiqui, 2011).
Fig. 2.5 Main Functional Parts of the IPTV System National
Broadcaster
VoD
Meta -data
Core Network Regional Head-End
Access Network User Terminal
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Many researchers have discussed the performance of IPTV systems and how to improve the quality of service provided to users. Due to the requirements of an IPTV in terms of its performance and reliability, network bandwidth becomes critical (Mahimkar et al., 2009). A study has been carried out by Simsarian to discuss the traffic and required bandwidth that must be streamed to each user. It was found that the bandwidth depends on where Video-on-Demand (VoD) content, its cache and streaming server is located. Therefore, in order to decrease the traffic on the core network and the required bandwidth, VoD content is normally cached in the Regional Head-End (Simsarian & Duelk, 2007).
Due to the popularization of IPTV, many services have been added to offer more facilities for the users such as on demand and interactive multimedia services. With an increase in the number of channels and content providers, assisting users in making selection becomes crucial. However, creating the EPG in the user device or centralizing the generation of EPG in the main servers can cause more challenges especially when the user experience and available bandwidth will be discussed (Cha, Rodriguez, Crowcroft, Moon, & Amatriain, 2008).
IPTV services have been delivered to users through mobile devices to watch TV content based on a cloud network. Lai proposed a personalized mobile IPTV system which allows a user to configure a browsing interface with EPG information and select their favourite TV programmes through their mobile devices. Then, based on those selections, the manager server searches for multimedia videos in the cloud within the User Generating Content web site or VoD server. The management part of the system produces the list of content to match the EPG information and metadata parser engine. Based on the degree of similarity, the system chooses the most appropriate videos and presents them to the users through their mobile devices. This system is shown in figure 2.6 and comprises a management server, which includes the multimedia parsing engines and is connected to the VoD server, and a personalized user interface which is used by the user to select their favourite videos (Y. X. Lai, Lai, Hu, Chao, & Huang, 2011).
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Fig. 2.6 Overall Structure of personalized mobile IPTV system (Y. X. Lai et al., 2011)
Many other researchers have discussed different aspects in the IPTV systems such as improving the EPG via more interactive services, user experience and improving the system transmission performance and quality of services to decrease the factors that affecting the service such as Jitter or packet loss. However, there are still many limitations relevant to improve the EPG especially the limited content channels and sources and difficulty of recommending an accurate personalized list of programmes that match the user viewing behaviour and wishes.