FIXED MOBILE CONVERGENCE
Abstract main standardization area of each. FMC network
architecture and examples about the call cases are
Fixed mobile convergence means that fixed and presented in chapter 4. Chapter 5 covers end user
wireless networks will merge and end users are able to services related to fixed mobile convergence. Chapter 6
get the same services no matter which access and 7 concentrates on effects to operator business
technology or terminal device they use. FMC is an models and vendor strategies. FMC challenges are
opportunity for different types of operators. They get introduced in chapter 8 and chapter 9 contains the
some new ways to get revenue from their existing conclusions.
networks and possibly new types of subscribers because
of the large variety of access technologies.
2. Overview of Fixed Mobile Convergence
For end users FMC brings easiness to use all services
via best available access network with one terminal. The concept of fixed mobile converge is not anything
The target is also to charge all services with one bill. new. It was introduced already 1990’s. However at that
Examples about the services are VoIP, presence, push- time the technology was not mature enough and there
to-talk , instant messaging and interactive gaming. were no unified standards. There were neither proper
terminals nor appropriate market business drivers. At
The core of the FMC architecture is 3GPP standardized that time FMC strategies were based for example on
IP multimedia subsystem together with IETF SIP intelligent network platform that supports both fixed
protocol. and mobile users (Vrdoljak 2000, Ciannetta 1999).
The target of fixed mobile convergence is to have all
Key Words services seamlessly available from any network and
Convergence, IMS, SIP with any terminal device. In practice this means device
convergence, service and application convergence and
network convergence. Device convergence means that
1. Introduction one mobile device supports several access technologies
and in addition to telephony some other functions such
There are different kinds of operators in the market: as camera or TV. Service convergence means that the
fixed operators, mobile operators, hybrid operators and same services can be provided to the user over different
mobile virtual network operators (MVNOs). All of access networks and to different devices. Network
those have realized that the competition in the market convergence gives the possibility to access the core
becomes more and more tough and the revenues are network and services via different access technologies.
getting smaller or coming close to zero. Fixed operators
realize that their subscribers have a tendency to replace Separate wireless, wireline and data networks will
their fixed phones with a mobile phone and mobile merge and it is possible to access to the unified core
operators are lacking high bandwidth that the fixed network via different access technologies. Using
operators can offer to their subscribers. Therefore new common technologies and common services in the fixed
strategies and business opportunities are needed. One and mobile networks end users can reach all services
good possibility is fixed mobile convergence. with the same terminal. 3GPP specified IMS
architecture and IETF SIP protocol are the main
For MVNOs fixed mobile convergence makes it building blocks in this architecture. IMS is the core of
possible to utilize both fixed and mobile operators the fixed mobile convergence architecture. IMS handles
networks. This means that MVNOs can offer services to the SIP sessions between terminals. GPRS and 3G
end users more flexible and efficient way. Mobile networks are offering data connections to the network
operators can enhance their coverage for example by servers but IMS gives the possibility to have mobile to
using UMA technology which means higher data rates mobile sessions. Application servers behind the IMS are
inside the buildings over WLAN and handovers to offering services like push-to-talk and presence.
GSM or 3G networks when needed. Hybrid operators
can reduce their costs by optimizing their networks. One difficult aspect in FMC is how to enable a set of
Fixed operators can co-operate with mobile operators or new services so that they work in every location, with
enlarge their coverage towards mobile access by using any access technology and terminal device. Especially
multi radio terminals with WLAN access or UMA. seamless handovers from one access network to another
are a challenge. Common standards play a key role in
In chapter 2 is presented the overview of fixed mobile FMC because otherwise equipments from different
convergence. Chapter 3 covers the main vendors are incompatible which makes it difficult to
standardization bodies related to FMC and tells the
reach the main target: same services available no matter
the network and access technology.
FMC makes it possible to have SIP sessions between
different kinds of terminal devices. These SIP sessions
3. Status of Related Standards can include VoIP, video sharing, gaming, messaging
Fixed mobile convergence merges different types of
networks. This means that lots of protocols and In figure 1 there is two call cases presented. In case
different types of architectures are involved. It is thus number 1 SIP client in a PC makes a voice call to POTS
essential to the vendors, operators and finally also to the phone. Before the SIP session can be established both
end users to have common standards related to FMC. the PC client and POTS phone have to register
Otherwise interoperability problems prevent the themselves to the IMS. SIP client in the PC can do it by
efficient use of network resources. itself but in case of the POTS phone the POTS card in
DSLAM (Nokia D500) does the registration of behalf of
The main standardization bodies related to FMC are 3rd the POTS phone. When PC client initiates a VoIP call
Generation Partnership Project 3GPP and Internet towards the POTS phone the SIP invite message is sent
engineering task force IETF. 3GPP have defined SIP- to the IMS. The logical function that handles the session
based IP multimedia subsystem (IMS) for telephony control in IMS is called call state control function
and other services. It is based on IETF work with some (CSCF). P-CSCF is the logical entity which IP address
extensions. The core IMS architecture was introduced has to be known by the mobile. I-CSCF is the
in 3GPP release 5. Release 6 adds some improvements interrogating CSCF and S-CSCF is a SIP-server that
to this architecture such as CS-IMS interworking. controls the services of the users. When the SIP session
Circuit switched - IMS interworking makes it possible has been set up between the users the actual speech
to set up a call between SIP client in IMS domain and a packets are routed using normal IP routing, these
normal 3G mobile in circuit switched network. Also packets do not go through the IMS.
UMA was introduced in release 6. 3GPP is continuing
its work in release 7. In case number 2 a multiradio terminal is registered to
IMS via WLAN access point. The other terminal has
IETF is the main standardization body for internet made a location update to the MSC server via 3G radio
protocols especially it is the originator of the SIP access network. When the call is set up the SIP invite
standards (RFC 2543). ETSI TISPAN handles fixed goes first to IMS which routes the call to the MSC
telephony network standardization and is specifying IP server. MSC server realizes that subscriber B is in its
and SIP-based NGN architecture based on 3GPP IMS VLR database and starts normal paging procedure.
release 6. Open Mobile alliance (OMA) is working on When the session is setup A and B can start the
SIP-based services which are used on top of IMS. conversation and possibly add to the session other
Examples of these applications are Push-to-talk and elements like messaging or video.
Because IMS is the centralized point in the convergence
network it is possible to share some resources regardless
of the service or access type. These resources include
4. FMC Network Architecture for example charging, presence, group and list
functions, provisioning, session control and operation
Figure 1 shows a simple FMC network architecture. In and management (Kataria, 2005).
this example the IMS is connected to access network
via session border controller, Push-to-talk application
server and to the MSC server which makes CS-IMS 5. End User Services
End users want the price and quality of fixed wireline
and the convenience of mobile wireless. For end users
FMC means the possibility to have one terminal which
is capable of handling all the needed access
technologies and services. Also all the services can be
charged with one bill.
Fixed mobile convergence association FMCA is an
alliance of telecom operators whose objective is to
accelerate the development of convergence
products and services. FMCA has listed
convergence service scenarios (FMCA). Here are
the most important ones:
1. Converged contacts is a service that provides
personal contacts and address book in the network-
Fig 1. FMC network architecture. based storage. This storage should be accessible
from any device and the terminal is able to always via the best possible access network and
synchronize the local address book based on they can use the same set of services by using the
information from central network-based storage. same terminal device. The challenge for operators
2. Personal multimedia provides secure access to the is to provide feature consistency across different
user’s multimedia content that is stored in home or kinds of networks both wireline and wireless. Also
in the network from any device. broader coverage is needed.
3. Multimedia call with data sharing service makes
it possible for the user to switch between voice only For operators the FMC means possibilities to
GSM call and multimedia call containing e.g. remain competitive, differentiate themselves from
picture or broadband-enabled TV. The service others and opportunity to grow into the new areas
automatically detects which kinds of networks are which can mean new different type of customers
available. and revenue opportunities. In general FMC offers
4. Combinatorial services are based on availability two main benefits to the operators: interoperability
of multiple connections (circuit and data) during and reduction of the costs because common
the same communication session. For example it is resources can be used.
possible to add to the voice call messaging (SMS/
MMS/IM), video streaming and one or more data FMC is a way for mobile operators to access fixed
flows (file sharing). network. This means a threat for fixed operators
5. Electronic Programme Guide service is listing who have to develop new strategies. Cellular
available programmes that can be watched on the markets in many industrial countries are almost
mobile device or recorded on video recorder. saturated and therefore also mobile operators have
6. Automation control and monitoring service to find new revenue opportunities. Trying to get
makes it possible to control various home based more subscribers does not work any more. The
tasks via the mobile device such as temperature and existing subscribers should increase their usage of
access. services which leads to the conclusion that new
7. Convergent call control provides the ability to attractive services are needed. Seamless roaming
automatically handle the call based on some events. from one access technology to another is essential.
For example based on the information of the user’s Handsets (multiradio terminals) capable of
electronic calendar, the location of the user and the handling several access technologies will have a
importance of the caller the call will be connected key role.
to the user or to the voice mail etc.
8. Multimodal services include several scenarios Inter working with existing networks is very
where voice and data sessions are mixed. important. When operators are developing their
networks towards FMC the solutions must be
In addition to VoIP calls other services commercially adjusted to each operator. Also regulations might
available for end users are for example video sharing be different in different countries.
and instant messaging. Presence service enriches other
applications, for instance push-to-talk service benefits if Ficora has made a report (Ficora 2006) about the
the user can see from the contact list who are available investment plans of the Finnish operators in the near
for group talk. Interactive gaming and chat give nice future. The report tells that the amount of investments is
entertainment for users. going to increase because of the equipment needed for
convergence and next generation networks. On the other
Though IMS gives the possibility to have all above hand the operators believe that they will get remarkable
mentioned services most probably voice remains the cost savings by using IP based techniques. Also they
most widely used service in fixed and mobile networks. believe that convergence will bring new services for end
Voice is an example of convergent service because it users.
can be offered across both networks (Kataria 2005).
Some other services such as SMS and instant messaging Like many other emerging industries FMC is a
are associated with a specific network. To be able to continuously changing and complex environment
send a text message from SIP client to 3G mobile a which creates uncertainties at technology, demand
conversion from instant message to SMS is needed. The and strategy levels (Wong 2006). The
target is to introduce new services in a transparent way technological uncertainties are caused by rapid
over both types of networks. technological development and the developing
standards. Despite the fact that there is a general
understanding about the huge potential of FMC
there are many open questions related to the new
6. Influence to Operator Business services. What are the services that the users are
Models willing to pay will be seen in the future. All these
questions cause uncertainty in demand level.
End users expect from operators simplicity of Strategic uncertainties are common to all emerging
services, simplified charging and quality. FMC is industries. A clear framework is needed to prevent
one possibility to get closer to these targets. With the operators to do costly mistakes by entering and
FMC the end users are connected to the service
subsequently exiting non-core businesses and
markets. FMC gives lots of possibilities but on the other hand it
means also new investments to operators. Common
FMC applications can be segmented in two standards have a great importance. Without
markets: consumer and business. In general standardization the equipment of different vendors
consumers want to be entertained and communicate cannot be integrated together and operators cannot
with friends and family. Business users on the other utilize their networks in the best possible way.
hand need good connections and high bandwidth.
Enterprises invest a lot to enterprise Standardization work is still going on. A question is
communications systems (PBX). also how much the end users are willing to pay for the
services. For example many users think that VoIP
services should be free of charge. This is due to the fact
7. Vendor Strategies that for example with skype the users can already have
free VoIP calls in the Internet.
The fact that operators want to reuse their existing
networks has to be taken into account by vendors. Many
vendors have different kinds of evolution paths and References
step-by-step network introduction to the FMC and all IP
networks. UMA solution is offered by many vendors to Vrdoljak, M., Vrdoljak, S., Skugor, G. 2000. “Fixed-
access the network over WLAN. Then the main solution Mobile Convergence Strategy: Technologies and
is based on IMS. Seamless roaming and availability of Market Opportunities”, IEEE Communications
services are key messages to the operators. Magazine, pp. 116-121.
Vendors have realized that standardization is a key Ciannetta, M. C., Colombo, G., Lavagnolo, R., Grillo,
issue if they want to provide solutions that can be D., Bordoni, F. 1999. ”Convergence Trends for Fixed
integrated to the equipment of other vendors. Most of and Mobile Services”, IEEE Personal Communications.
the vendors have taken an active role in many
standardization bodies. 3GPP.
8. FMC Challenges IETF.
Nowadays there are clear strategies how to implement
FMC. Several standardization bodies concentrate on the OMA.
related standards and there are already some attractive http://www.openmobilealliance.org.
end user services available. Still FMC is facing some
challenges that need to be solved (Safavian, 2006). TISPAN.
1. Number plans and number portability. Fixed and http://portal.etsi.org/tispan .
mobile numbers come from separate blocks and they
have prefixes that contain information for FMCA. 2006. FMCA Convergence Application
interconnection charging. Currently there is separate Scenarios.
fixed number portability and mobile number portability http://www.thefmca.com/assets/pdf/FMCA_Convergen
available but not fixed/mobile number portability. ce_Application_Requirements_Rel_1.0.pdf, referenced
2. Directory services. Fixed operators provide on 26th of March 2007.
directory service to their customers. This catalogue
contains information on all fixed line customers. Kataria, D., Logothetis, D. 2005. “Fixed Mobile
Currently mobile operators do not offer this kind of Convergence: Network architecture, Services,
service and mobile numbers are considered as personal Terminals, and Traffic management”, IEEE 16th
data. International Symposium on Personal, Indoor and
3. Handset availability is always a problem in the early Mobile Radio Communications, pp.2289-2293.
stages of any telecommunications technology.
4. Role of regulators. There are two opposite views Wong, C., Low, A., Hiew, P. 2006. “Fixed-mobile
about the role of regulators in FMC. One point of view Convergence: Creating Values with Appropriate
is that it is not a task of regulators to decide the rules for Business Models”, Information and Communication
FMC. Regulators should only set up the environment so Technologies, pp.17-22.
that the market forces can guide direction, extent and
pace of FMC. Another point of view is that since the Ficora. 2006.
definitions of information, data and entertainment has http://www.ficora.fi/attachments/suomi_A_L/5lfirw4K
changed the rules related to network and service O/Files/CurrentFile/Investointiselvitys2006.pdf ,
providers should change accordingly. referenced on 21st of April 2007.