ters. 6 Services in Fixed and Mobile Ultra-Broadband Table 6.2 Categories for voice transmission quality. Range of E-model Voice transmission rating R quality category User satisfaction 90 < R < 100 Very satisfied 80 < R < 90 Satisfied 70 < R < 80 Medium Some users dissatisfied 60 < R < 70 Many users dissatisfied 50 < R < 60 Nearly all users dissatisfied The idea of R factor is to be used to determine voice transmission quality. Table 6.2 maps R factor values to five voice transmission quality categories (similar to MOS grades), which can be used for planning purposes by network and service planners. 6.3.2 QoE for IPTV IPTV services provided over the broadband and ultra-broadband access network require a certain level of QoS to support adequate QoE. QoE depends upon two main technical elements: IPTV application (transmit and receive side). Quality of the video source, resolu- tion (HDTV, full HD, etc.), required bitrate, constant or variable bitrate encoder out- put, group of pictures (GoP) size, and structure in Moving Pictures Experts Group (MPEG) (e.g. more B frames in the GoP reduces the required bitrate, but video is more sensitive to bit errors and packet loss), etc. Network transmission parameters. The IPTV QoE is highly dependent on the type of data loss (especially on I and P frames losses from the MPEG streams). Further, it is dependent upon the codec being used, MPEG transport stream packetization, packet losses, outage (e.g. due to multicast router table recovery), etc. Packet loss for IPTV is defined with loss period and loss distance. The loss period is the time duration of consecutive packet losses and the loss distance is the time between packet loss intervals. According to the Broadband Forum [16], the loss distance should be limited to at most one error event per 60 minutes for SD and one error event per 4 hours for HD. In practice, the error event is a loss or corruption of a group of a small number of IP packets where each of them contains, for example, up to 7 MPEG packets of 188 bytes in len