A MIXED SATELLITE TV CHANNEL TRANS. SCHEME TO ENHANCE FREQ. BANDWIDTH UTIL. 3
and DVB-RCS [8] technologies. Similarly, Gardikis et al. [9, 10] discussed the application of the
adaptive coding and modulation (ACM) feature of DVB-S2 in the provision of satellite triple play
services over an interactive DVB-S2 / DVB-RCS network in order to compensate for fluctuations in
propagation conditions. One key point to implement the triple play service in the above literature is
to establish backward link, and this is also the truth for the mixed transmission scheme proposed in
this paper.
Generally, for TV transmission systems based on the broadcast method, such as terrestrial TV,
cable TV, and legacy satellite TV, all the provided TV channels are simultaneously delivered to
viewer premises and the transmission bandwidth requirements are constant. Consequently, there
are very few researches working on decreasing the bandwidth consumption in broadcast based TV
transmission networks. On the other hand, for the multicast based TV systems (one most typical
example is IPTV), there exist quite amount of research efforts dealing with the potential bandwidth
shortage challenge in TV multicasting networks [11, 12, 13]. More precisely, in [11, 12], Lai et
al. proposed a link state-vector-based model to simulate IPTV systems in detail, and derived a
TCAC (TV channel access control) scheme to decrease bandwidth consumption and thus to improve
channel availability in a bandwidth limited IPTV system. Abdollahpouri et al. [13] illustrated that
using multiple unicast flows sometimes can be a better choice than using multicast in terms of
transmission bandwidth saving in IPTV transmission networks. However, none of the schemes
proposed in the above literature can be directly adopted to solve the bandwidth shortage problem,
which is identified in the satellite TV systems depicted in this paper.
Different from broadcast based TV delivery systems, user behaviour can directly influence the
traffic loads on the transmission networks of multicast or unicast based TV systems. A plenty
of existing research efforts have been carried out on traffic characterization and user behaviour
measurement, analysis, and modelling in multicast based IPTV systems. In [14] Qiu et al. studied
a large national IPTV system and developed a series of analytical models for different aspects of
user activities. Ramos et al. [15] modelled the behaviour of a typical user as a rapid burst of channel
selection events followed by an extended period of channel viewing. Yu et al. [16] investigated
IPTV user activities in terms of zapping rate and session lengths. Cha et al. [17] studied how
users select channels in the real world based on a comprehensive trace from a commercial IPTV
service, including channel popularity dynamics, aggregate viewing sessions and content locality.
Abdollahpouri et al. [18, 19] modelled the channel switching behaviour of a single IPTV user.
Both channel popularity and user activities have been taken into account. The proposed IPTV user
behaviour automaton (IPTV-UBA) model relies on formal descriptions to capture the characteristics
of user behaviours. The aggregate user behaviour can be derived by overlaying the behaviours of
a set of users. Based on the fact that multiple individual users may be associated with one IPTV
account, and it is difficult to identify individual users, Zhang et al. [20] proposed a time-topic
coupled latent Dirichlet allocation (LDA) model which considers the topic of TV programs viewed
as well as the timestamps of the viewing behaviours, in order to capture the inherent viewing patterns
of individual users along the topic as well as the time dimensions. Although the aforementioned
literature mainly focus on IPTV, their methodologies and the conclusions are highly likely to be
valid for the multicast based satellite TV transmission method proposed in this paper. In particular,
TV channel popularity as one most important aspect of user behaviour will be explained in more
detail in Section 6 of this paper.
TV video formats in the last two decades have been rapidly developing from SD to HD. At
present, the most promising TV video formats are the ultra HD [1] and 3D [2], which brings viewers
much more vivid images and experiences. There have already been practical trials and numerous
researchers working on broadcasting TV channels in those enhanced video formats. In [21], Shin et
al. presented an efficient way for providing satellite ultra HD broadcasting services via Ka frequency
band. In [22], You et al. proposed 3DTV systems and introduce demonstrations for providing 3DTV
service over HFC network. Kim et al. [23] illustrated DVB-T2 fixed and mobile hybrid 3DTV
system design and implementations for DVB-T2 terrestrial 3DTV broadcasting services. In [24],
Kim et al. carried out a study on the feasibility of providing dual-channel 3DTV service via ATSC-
M/H. All the above research efforts indicate the trend that satellite TV service will be very soon
Copyright
c
2016 John Wiley & Sons, Ltd. Int. J. Commun. Syst. (2016)
Prepared using dacauth.cls DOI: 10.1002/dac