IPTV over satellite
Although IPTV and conventional satellite TV distribution have been seen as complementary technologies, they are likely to be increasingly used together in hybrid IPTV networks that deliver the highest levels of performance and reliability. IPTV is largely agnostic to the transmission medium, and IP traffic is already routinely carried by satellite for Internet backbone trunking and corporate VSAT networks. The use of satellite to carry IP is fundermental to overcoming the greatest shortcoming of IPTV over terrestrial cables – the speed/bandwidth of the connection.
The copper twisted pair cabling that forms the last mile of the telephone/broadband network in many countries is not able to provide a sizeable proportion of the population with an IPTV service that matches even existing terrestrial or satellite digital TV distribution. For a competitive multi-channel TV service, a connection speed of 20Mbps is likely to be required, but unavailable to most potential customers . The increasing popularity of high definition TV (with twice the data of SD video) increases connection speed requirements, or limits IPTV service quality and connection eligibility, yet further.
However, satellites are capable of delivering in excess of 100Gbps via multi-spot beam technologies, making satellite a clear emerging technology for implementing IPTV networks. Satellite distribution can be included in an IPTV network architecture in several ways. Simplest to impliment is an IPTV-DTH architecture, in which hybrid DVB/broadband set-top boxes in subscriber homes integrate satellite and IP reception to give near-infinite bandwidth with return channel capabilities. In such a system, many live TV channels may be multicast via satellite (IP-encapsulated or as conventional DVB digital TV) with stored video-on-demand transmission via the broadband connection. Arqiva’s Satellite Media Solutions Division suggests “IPTV works best in a hybrid format. For example, you would use broadband to receive some content and satellite to receive other, such as live channels”.
An alternative approach is the IPTV version of the Headend in the Sky cable TV solution. Here, mutilple TV channels are distributed via satellite to the ISP or IPTV provider’s point of presence (POP) for IP-encapsulated distribution to individual subscribers as required by each subscriber.
This can provide a huge selection of channels to subscribers without overburdening Internet trunking to the POP, and enables an IPTV service to be offered to small or remote operators outside the reach of terrestrial high speed broadband connection. An example is a network combining fibre and satellite distribution via an SES New Skies satellite of 95 channels to Latin America and the Caribbean, operated by IPTV Americas.
While the future development of IPTV probably lies with a number of coexisting architectures and implementations, it’s clear that broadcasting of high bandwidth applications such as IPTV is accomplished more efficiently and cost-effectively using satellite and it’s predicted that the majority of global IPTV growth will be fuelled by hybrid networks.
” flowing into the home. A switched IP network works differently. Content remains in the network, and only the content the customer selects is sent into the customer’s home. That frees up bandwidth, and the customer’s choice is less restricted by the size of the “pipe” into the home. This also implies that the customer's privacy could be compromised to a greater extent than is possible with traditional TV or satellite networks. It may also provide a means to hack into, or at least disrupt (see Denial of Service) the private network.
Interactivity
An IP-based platform also allows significant opportunities to make the TV viewing experience more interactive and personalized. The supplier may, for example, include an interactive program guide that allows viewers to search for content by title or actor’s name, or a picture-in-picture functionality that allows them to “channel surf” without leaving the program they’re watching. Viewers may be able to look up a player’s stats while watching a sports game, or control the camera angle. They also may be able to access photos or music from their PC on their television, use a wireless phone to schedule a recording of their favorite show, or even adjust parental controls so their child can watch a documentary for a school report, while they’re away from home.
Note that this is all possible, to some degree, with existing digital terrestrial, satellite and cable networks in tandem with modern set top boxes. In order that there can take place an interaction between the receiver and the transmitter a feedback channel is needed. Due to this terrestrial, satellite and cable networks for television does not allow interactivity. However, interactivity with those networks can be possible in the combination with different networks like internet or a mobile communication network.
VoD
VoD stands for Video on Demand. VoD permits a customer to browse an online programme or film catalogue, to watch trailers and to then select a selected recording for playback. The playout of the selected movie starts nearly instantaneously on the customer's TV or PC.
Technically, when the customer selects the movie, a point-to-pointdisambiguation unicast connection is set up between the customer's decoder (SetTopBox or PC) and the delivering streaming server. The signalling for the trick play functionality (pause, slow-motion, wind/rewind etc.) is assured by RTSP (Real Time Streaming Protocol).
The most common codecs used for VoD are MPEG-2, MPEG-4 and VC-1.
In an attempt to avoid content piracy, the VoD content is usually encrypted. Whilst encryption of satellite and cable TV broadcasts is an old practice, with IPTV technology it can effectively be thought of as a form of Digital Rights Management. A film that is chosen, for example, may be playable for 24 hours following payment, after which time it becomes unavailable.
IPTV based Converged Services
Another advantage of an IP-based network is the opportunity for integration and convergence. This opportunity is amplified when using IMS-based solutions . Converged services implies interaction of existing services in a seamless manner to create new value added services. One good example is On-Screen Caller ID, getting Caller ID on your TV and the ability to handle it (send it to voice mail, etc). IP-based services will help to enable efforts to provide consumers anytime-anywhere access to content over their televisions, PCs and cell phones (for example see http://www.ericsson.com/campaign/televisionary/), and to integrate services and content to tie them together. Within businesses and institutions, IPTV eliminates the need to run a parallel infrastructure to deliver live and stored video services.