. Internet Protocol Television (IPTV)
Using the architecture and networking methods of Internet Protocol suite over a packet switched network infrastructure, the service which are delivered using the above scenario is said to Internet Protocol Television.
The Internet and broadband Internet access networks are the examples, instead of being delivered through traditional radio frequency broadcast, satellite signal, and cable television (CATV) formats.
IPTV services are classified into three groups: live television, time-shifted programming, and content (or video) on demand. It is distinguished from general Internet-based or web-based multimedia services by its on-going standardization process and preferential deployment scenarios in subscriber-based telecommunications networks with high-speed access channels into end-user premises Set-Top boxes or other customer-premises equipment.
IPTV covers both live TV (multicasting) as well as stored video (Video on Demand VOD). The playback of IPTV requires either a personal computer or a set-Top box connected to a TV. Video content is typically compressed using either a MPEG-2 or a MPEG-4 codec and then sent in an MPEG transport stream delivered Via IP Multicast in case of live TV or via IP Unicast in case of Video on Demand. IP Multicast is a method in which information can be sent to multiple computers at the same time. The newly released (MPEG-4) H.264 codec is increasingly used to replace the older MPEG-2 codec.
Network Personal Video Recording is a consumer service "PVR that is built into the network" - however that would be slightly misleading unless the word "Personal" is, of course, changed to "Public" for this context where real-time broadcast television is captured in the network on a server allowing the end user to access the recorded programs on the schedule of their choice, rather than being tied to the broadcast schedule. The NPVR system provides time-shifted viewing of broadcast programs, allowing subscribers to record and watch programs at their convenience, without the requirement of a truly personal PVR device. It could be compared as a
Home Networks for IPTV distribution
In many cases, the Residential Gateway that provides connectivity with the Broadband Access network is not located in close proximity to the IPTV Set-Top Box. This scenario becomes very common as service providers start to offer service packages with multiple Set-Top Boxes per subscriber.
Traditional home networking technologies such as Ethernet and 802.11 do not provide a good solution to provide connectivity between the Gateway and each Set-Top Box. Most homes today are not wired with Ethernet cable in every room, and installing new Ethernet cables is expensive for service providers and undesirable for consumers. Wireless technologies like 802.11 are optimized for data transmission, but they usually don't provide the Quality of Service required by IPTV applications.
Networking technologies that take advantage of existing home wiring (such as power lines, phone lines or coaxial cables) have become a popular solution for this problem, although fragmentation in the wired home networking market has limited somewhat the growth in this market.
On December 2008, ITU-T adopted Recommendation G.hn (also known as G.9960), which is a next generation home networking standard that specifies a common PHY/MAC that can operate over any home wiring (power lines, phone lines or coaxial cables).
Distinction of IPTV from Internet TV
A Telco IPTV service is usually delivered over a complex and investment heavy walled garden network, which is carefully engineered to ensure bandwidth efficient delivery of vast amounts of multicast video traffic. The higher network quality also enables easy delivery of high quality SD or HD TV content to subscriber's homes. This makes IPTV by default the preferred delivery platform for premium content. However, the investment for a Telco to build an end-to-end IPTV service can be substantial.
By contrast "Internet TV" generally refers to transport streams sent over IP Networks (normally the Internet) from outside the network that connects to the users premises. An Internet TV provider has no control over the final delivery and so Broadcasts on a "best effort" basis. Elementary streams over IP networks and proprietary variants as used by websites such as YouTube are now rarely considered to be IPTV services
Compared to Telco IPTV, Internet TV is a quick-to-market and relatively low investment service. Internet TV rides on existing infrastructure including broadband, ADSL, Wi-Fi, cable and satellite which makes it a valuable tool for a wide variety of service providers and content owners looking for new revenue streams. However, due to the fact that IPTV is always delivered over low cost IP STBs, which have limited computing power, the capability for IPTV operators to provide diverse multimedia services are limited. This is where Internet TV has an advantage as it is delivered to a subscriber's (generally) powerful PC.
The relative ease of establishing an Internet TV service seems at first a threat to Telco IPTV operators' multimillion dollar investment, but both services do not necessarily compete for the same customers and there are some synergies between the two such as a common technology platform in the form of web-based technologies for content storage and delivery.
Broadcast IPTV has two major architecture forms: free and fee based. As of June 2006, there are over 1,300 free IPTV sources available. This sector is growing rapidly and major television broadcasters worldwide are transmitting their broadcast signal over the Internet. These free IPTV sources require only an Internet connection and an Internet enabled device such as a personal computer, HDTV connected to a computer or even a 3G cell/mobile phone to watch the IPTV content. Various Web portals offer access to these free IPTV sources. Some cite the ad-sponsored availability of TV series such as Lost as indicators that IPTV will become more prevalent.
Because IPTV uses standard networking protocols, it promises lower costs for operators and lower prices for users. Using set-top boxes with broadband Internet connections, video can be streamed to households more efficiently than current coaxial cable. Home networks currently use technology from the Multimedia over Coax Alliance, HomePlug Powerline Alliance or Home Phoneline Networking Alliance to deliver IPTV content to any set-top box in a home, without having to install new Ethernet wires and without relying on technologies like 802.11, which are not optimized for reliable delivery of video streams. ISPs are upgrading their networks to bring higher speeds and to allow multiple High Definition TV channels.
IPTV uses a two-way digital broadcast signal sent through a switched telephone or cable network by way of a broadband connection and a set-top box programmed with software (much like a cable or DSS box) that can handle viewer requests to access to many available media sources.
Local IPTV, as used by businesses for audio visual AV distribution on their company networks is typically based on a mixture of: a) Conventional TV reception equipment and IPTV encoders b) IPTV Gateways that take broadcast MPEG channels and IP wrap them to create multicast streams.
IPTV via 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 neutral 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 fundamental to overcoming the greatest shortcoming of IPT 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 20Mbit/s 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 100Gbit/s 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 implement 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”.
The Hybrid Broadcast Broadband TV (HbbTV) consortium of industry companies is currently promoting and establishing an open European standard for hybrid set-top boxes for the reception of broadcast and broadband digital TV and multimedia applications with a single user interface.
An alternative approach is the IPTV version of the Head end in the Sky cable TV solution. Here, multiple 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 fiber 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.
The IP-based platform offers significant advantages, including the ability to integrate television with other IP-based services like high speed Internet access and VOIP.
A switched IP network also allows for the delivery of significantly more content and functionality. In a typical TV or satellite network, using broadcast video technology, all the content constantly flows downstream to each customer, and the customer switches the content at the set-top box. The customer can select from as many choices as the telecoms, cable or satellite company can stuff into the “pipe” 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 the private network.
In the past, this technology has been restricted by low broadband penetration and by the relatively high cost of installing wiring capable of transporting IPTV content reliably in the customer's home. In the coming years, however, residential IPTV is expected to grow at a brisk pace as broadband was available to more than 200 million households worldwide in the year 2005, projected to grow to 400 million by the year 2010. Many of the world's major telecommunications providers are exploring IPTV as a new revenue opportunity from their existing markets and as a defensive measure against encroachment from more conventional Cable Television services. Also, there is a growing number of IPTV installations within schools, universities, corporations and local institutions.
IPTV is sensitive to packet loss and delays if the streamed data is unreliable. It has strict minimum speed requirements in order to facilitate the right number offrames per second to deliver moving pictures. This means that the limited connection speed/bandwidth available for a large IPTV customer base can reduce the services.
Although a few countries have very high speed broadband-enabled populations, such as South Korea with 6 million homes benefiting from a minimum connection speed of 100Mbit/s, in other countries (such as the UK) legacy networks struggle to provide 3-5 Mbit/s and so simultaneous provision to the home of TV channels, VOIP and Internet access may not be viable. The last mile delivery for IPTV usually has a bandwidth restriction that only allows a small number of TV channels - typically from one to three - to be delivered.
The same problem has also proved troublesome when attempting to stream IPTV across wireless links within the home. Improvements in wireless technology are now starting to provide equipment to solve the problem.
Due to the limitations of wireless, most IPTV service providers today use wired home networking technologies instead of wireless technologies like 802.11. Service Providers such as AT&T (which makes extensive use of wire line home networking as part of its U-Verse IPTV service) have expressed support for the work done in this direction by ITU-T, which has adopted Recommendation G.hn (also known as G.9960), which is a next generation home networking standard that specifies a common PHY/MAC that can operate over any home wiring (power lines, phone lines or coaxial cables).