 Now, we are going to look at the provisioning of mobile TV which is again a very specific kind of IP TV service over the well-known IEEE standard WiMAX and Wi-Fi. These two technologies are being considered here because these two technologies are basically IP centric. We look at these two technologies as the options and then we will see how WiMAX and Wi-Fi are suited for providing such service. Since IEEE basically provided lead to the IP-based service provisioning in 802.11 which is Wi-Fi and 802.16 which is Wi-MAX. It is important to look at the behavior adopted by both of these technologies in the domain of IEEE. So we are going to see how television broadcasting takes place in these two technologies. At the more higher layers, there are certain protocols which are common to both WiMAX and Wi-Fi because these technologies are the link layer technologies. So we have IP at the network layer, we have UDP at the transport layer and together we have the motion picture expert group MPEG standard which is basically a video encoding standard and the real time protocol family of protocols including RTP, RTSP, RTCP. So these protocols are at the upper layer but the main concern is how well suited are the two technologies for providing IPTV. As for Wi-MAX, since Wi-MAX provides a very high bandwidth and good data rate, it has the most important essential that it provides bandwidth. But does it provide quality of service? Yes, it does. In fact, we have already seen this. It has different classes of services. So for IPTV, the most important and relevant classes are the real time polling service and the extended or enhanced real time polling service. Now these two service types actually are well suited for IPTV because as you can see, the real time polling service actually is highly suited for periodic packet transmission. It means that the packet sizes may be varying, some packets may be large, some may be small but the periodicity is highly suited for real time polling service. IPTV is not the only service that is supported by real time polling service. In fact, voice over IP is also supported, which is bi-directional. In voice over IP, since it is mostly regarding audio visual conversation, so whenever the talkspot does not contain any audio, so the silence can be suppressed, saving certain bandwidth for usage by either video or for any other textual data that can be transmitted in line. Then we have the extended real time polling service. Again, it is suited for periodic traffic both with active and silent intervals. It is related to voice over IP. It doesn't have much concern with IPTV, but it supports both. But the extended real time polling service actually helps for video and multimedia streaming in the sense that it involves more negotiation features as compared to simple real time polling service. So extended real time polling service has more negotiation options which are available between two interacting parties. Ymax is highly suited for providing QS based IPTV service. Let's look at Wi-Fi. To begin with, we already know that Wi-Fi is highly deployed and it should be and preferably can be used for delivering the IPTV content down to the user, but there are certain constraints and limitations. Number one, it is not based on TDMA. It is contention based, which limits its application because any fluctuation in spectrum allocation in resource contention, the QS is going to drop at an unacceptable level. And then it is based on the ISM unlicensed band. So that also is again not much suited for delivery of Wi-Fi, but the only good thing about Wi-Fi is it's highly deployed and this is something which is part of every household. So QS can be compromised, but the wide deployment has to be and cashed and utilized. And this is something that people are comfortable with because it is only the last hop which is in your house that is carrying this IPTV traffic in your house. So quite likely within a certain geographical area like a room, like a floor or a building, there isn't much expectation of certain and unexpected service degradation because the number of competing sources are not there because a Wi-Fi access point is likely to interfere with another Wi-Fi access point in the downstream. If that does not happen, it becomes an acceptable choice. Now, does Wi-Fi offer quality of service? There is a variant, yes it does. It is IEEE 802.11e. It calls actually the class of service or type of service as the access categories. Now, the access category is something that we haven't come across, but it is almost the same as the type of service. So different classes of service or type of service can be mapped to different access categories and 802.11e provides differentiation in terms of traffic prioritization, admission, resource allocation and scheduling for these access categories.