IPTV Over Wireless Networks

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New broadband wireless networks provide telecom operators with another alternative distribution platform to deliver IPTV services to households. Various options are available and are described in the following sections.
Fixed WiMAX
Demands from consumers and the telecommunication sector to use WiMAX as a platform to carry IPTV content is growing at a steady pace. WiMAX (Worldwide Interoperability for Microwave Access) is a high capacity IP broadband wireless technology that is considered by the industry to be a close “relative” of the Wi-Fi family of wireless standards. It defines a number of services that conform to the IEEE 802.16 technical standard. The WiMAX Forum, an industry association, is responsible for developing WiMAX specifications, promoting the technology, and FIGURE 2.9 Simplified block diagram of a WiMAX System carrying IPTV traffic.FIGURE 2.10 WiMAX communications model managing the overall certification of WiMAX products. The organization boasts a membership of over 370 companies at the time of writing this book. Figure 2.9 shows a simplified diagram of two WiMAX broadcast cells connected together and delivering video content to a number of IPTV end users.The technical characteristics of fixed version of WiMAX follow. 

Operating Frequencies WiMAX will operate within licensed and unlicensed frequency bands. These bands have been allocated by various communication regulation bodies around the world. The licensed bands are the preferred operating frequency option for real-time applications such as IPTV because there is less chance of interference occurring. Fixed WiMAX operates in frequencies of 3400 3600 MHz.

Physical and MAC Layer Protocols As depicted in Fig. 2.10, the 802.16 communications model defines three layers: physical, MAC, and transport.WiMAX Physical Layer Properties Under the WiMAX standard, equipment manufacturers have a choice between three different PHY options when building products:

(1) The Single Carrier physical layer option is intended for straightforward line of sight applications.

(2) The Orthogonal Frequency Divisio n Multiplexing (OFDM) option is the most popular physical layer choice for most WiMAX equipment manufacturers because of its ability to deal with the issue of multipath propagation. This feature means that OFDM based WiMAX technologiesare particularly suited to the delivery of IPTV services.

(3) Orthogonal Frequency Division Multiple Access (OFDMA) is the most sophisticated option and is capable of separating user connections on the upstream frequency channels.