Wireless Network Design: Optimization Models and Solution ...

356 Khiem Le
a new paradigm is needed to address it. Another long standing cost contributor is
the spectrum. As licenses cost hundreds of millions or billions of dollars, operators
make every effort to use the spectrum as efficiently as possible.
Convergence with the Internet is a major trend that affects the MNO’s revenues
[26]. The “Web2.0” with players such as YouTube, Facebook and MySpace is growing
fast, and using business models based on indirect revenues rather than revenues
from direct charging for usage. These business models challenge Communication
Service Providers (CSPs) traditional user fee based revenue model. (In this chapter,
CSPs is a generic term that also includes wireline and hybrid operators.) The Web
2.0 Internet players are diversifying their offerings and are starting to cannibalize
not only CSPs core business, such as voice services, but also new growth opportunities
in areas such as IPTV. According to estimates, in some markets about half of
users time spent on communication services is already occupied by Internet based
messaging and VoIP services. Web video and TV platforms are posing as competition
to IPTV. As the boundary between fixed and mobile access gets more fuzzy
with the technical advances of wireless technologies, the cannibalization trend also
takes place for MNOs. The appeal and variety of usage scenarios for Instant Messaging
(IM) in a Web 2.0 world is a threat to profitable Short Message Service (SMS)
and voice business. Google’s mobile operating system “Android” is an attempt to
gain direct access to mobile consumers, bypassing MNOs. Google has introduced
Google Voice, a service offering cheap voice calls that supports multiple features including
allowing a user to access his voicemail online, read automatic transcriptions
of his voicemail, and create personalized greetings based on the caller.
Some MNOs have been very successful at gaining new subscribers by offering
mobile devices with an attractive menu of applications and user friendly interface
for which they have exclusive rights. An example is AT&T with the iPhone. The
downside is that these applications tend to generate a disproportionate amount of
traffic on the MNO’s network. AT&T has experienced a 50-fold mobile data traffic
increase from 2006 to 2009 [19]. This example illustrates the challenge the MNOs
are facing as the traffic explodes, but the revenues do not grow in the same proportion.
Network operators’ core assets include the subscribers identity infrastructure [5]
and the capability to issue billing to the users. The subscribers identity infrastructure
corresponds to the subscribers’ identities and associated security credentials in
the operators’ databases along with the existing network mechanisms to authenticate
subscribers and control their access to the network services, and the Subscriber
Identity Modules (SIMs). SIMs are by far the most widely deployed secure devices
in the world, and MNOs master the process of managing the lifecycle of SIMs.
Additionally, roaming agreements between operators provide a globally interconnected
“network of trust” [5]. The subscribers identity infrastructure is truly an
asset unique to the mobile operators, considering that the population of mobile subscribers
now exceeds 4 Billion [4] and is growing. No other industry can boast
such a large network of trust. Closely linked to the subscribers identity infrastructure
is the network operators’ capability to record a subscriber’s usage down to a
fine granularity (e.g., minutes or seconds of use), consolidate and generate a bill.