nvented for VoIP, but it continues to be used for voice services regardless of whether they are analogue telephony, digital telephony, or VoIP telephony. The QoE of voice is rated with a five-point MOS for voice quality assessment (where 1 = bad, 2 = poor, 3 = fair, 4 = good, 5 = excellent). MOS is defined as "the mean of opinion scores" [9], where the opinion score is initially defined (in ITU-T P10/G100 [11]) as "the value on a predefined scale that a subject assigns to his opinion of the performance of the telephone transmission system used either for conversation or for listening to spoken material." There are definitions for different types of speech codecs, SO there is wide- band MOS (for voice in the range 50-7000 super-wideband MOS (20-14 000 Hz), and full-band MOS (10-20 000 Hz) [9]. Also, for voice communication, MOS can be related to listening only situations or to conversational situations. However, one should note that further MOS is not exclusively defined for voice services (e.g. there is MOS for video and audiovisual services). To avoid the need for real people evaluation of the voice quality, there is standard- ized automated assessment of the speech quality called PESQ (perceptual evaluation of speech quality), defined in ITU-T P.862 [12] and P.863 [13]. This way, apart from subjec- tive testing (which includes people as quality evaluators), PESQ uses MOS for objective assessment in network planning and/or optimization. PESQ is defined as a one-way lis- tening model. It estimates user-perceived MOS by comparing the transmitted reference speech signal and the received degraded signal. It includes impairment effects due to voice compression and IP network parameters (e.g. packet delay, jitter, packet loss), in addition to conventional circuit-switched network impairments such as noise and echo (ITU-T P.862 [12]). The QoE assessment defined in ITU-T P.863 [13] is also known as POLQA (perceptual objective listening quality assessment). POLQA incorporates 6.3 QoE for VolP and IPTV SLR, RLR Home gatew