The demand for making air traveling more 'pleasant, secure and
productive for passengers is one of the winning factors for airlines and
aircraft industry. Current trends are towards high data rate communication
services, in particular Internet applications. In an aeronautical scenario
global coverage is essential for providing continuous service.
Therefore satellite communication becomes indispensable, and together
with the ever increasing data rate requirements of applications, aeronautical
satellite communication meets an expansive market.
Wireless Cabin (IST -2001-37466) is looking into those radio access
technologies to be transported via satellite to terrestrial backbones . The
project will provide UMTS services, W-LAN IEEE 802.11 b and Blue tooth to the
cabin passengers. With the advent of new services a detailed investigation of
the expected traffic is necessary in order to plan the needed capacities to
fulfill the QoS demands.
In the future, airliners will provide a variety of entertainment and
communications equipment to the passenger. Since people are becoming more and
more used to their own communications equipment, such as mobile phones and
laptops with Internet connection, either through a network interface card or
dial-in access through modems, business travelers will soon be demanding
wireless access to communication services.
Wireless Cabin Architecture
So far, GSM telephony is prohibited in commercial aircraft due to the
uncertain certification situation and the expected high interference levels of
the TDMA technology. With the advent of spread spectrum systems such as UMTS
and W-LAN, and low power pico-cell access such as Blue tooth this situation is
likely to change, especially if new aircraft avionics technologies are
considered, or if the communications technologies are in line with aircraft
development as today .
When wireless access technologies in aircraft cabins are envisaged for
passenger service, the most important standards for future use are considered
to be: UMTS with UTRAN air interface, Blue tooth, and W-LAN IEEE 802.11 b. Of
course, these access technologies will co-exist with each other, beside
conventional IP fixed wired networks. The wireless access solution is
compatible with other kinds of IFE, such as live TV on board or provision of
Internet access with dedicated installed hardware in the cabin seats. Hence, it
should not be seen as an alternative to wired architecture in an aircraft, but
as a complementary service for the passengers.
Several wireless access segments in the aircraft cabin, namely a
wireless LAN according to IEEE 802.11 b standard for IP services, an UMTS
pico-cell for personal and data communications, and Bluetooth1.1, as well as a
standard wired IP LAN.
A satellite segment for interconnection of the cabin with the
terrestrial telecom networks. The different cabin services must be integrated
and interconnected using a service integrator, that allows the separation and
transportation of the services over a single or several satellite bearers.
Peculiarities, such as limited bandwidth, asymmetric data rates on satellite
up- and down-link, and dynamic traffic demand between the different services
and handover between satellite bearers need to be addressed. In order to
minimize the cost (satellite resources) for a given QoS efficient interworking
between the service integrator and the satellite segment will be required.
An aircom service provider segment supporting the integrated cabin
services. The aircom provider segment provides the interconnection to the
terrestrial personal and data networks as well as the Internet backbone. For
the UMTS cabin service, a subset of the UMTS core network must be available.
The provision of such a heterogeneous access network with collectively
mobile users requires the development of new protocol concepts to support
· The integrated services with dynamic bandwidth sharing among the
services and asymmetrical data rate;
· IP mobility and virtual private networks (VPN) for the individual
passengers in the mobile network; authentication, admission and accounting
(AAA) in the mobile network, especially taking into account the necessity to
support different pricing concepts for each passenger in the mobile network and
the interaction of airline, satellite provider, aircom service provider and
terrestrial service providers.
Several wireless access segments in the aircraft cabin, namely a
wireless LAN according to IEEE 802.11 b standard for IP services, an UMTS
pico-cell for personal and data communications, and Bluetooth1.1, as well as a
standard wired IP LAN.
A satellite segment for interconnection of the cabin with the
terrestrial telecom networks. The different cabin services must be integrated
and interconnected using a service integrator, that allows the separation and
transportation of the services over a single or several satellite bearers.
Peculiarities, such as limited bandwidth, asymmetric data rates on satellite
up- and down-link, and dynamic traffic demand between the different services
and handover between satellite bearers need to be addressed. In order to
minimize the cost (satellite resources) for a given QoS efficient interworking
between the service integrator and the satellite segment will be required.
An aircom service provider segment supporting the integrated cabin
services. The aircom provider segment provides the interconnection to the
terrestrial personal and data networks as well as the Internet backbone. For
the UMTS cabin service, a subset of the UMTS core network must be available.
The provision of such a heterogeneous access network with collectively
mobile users requires the development of new protocol concepts to support
• The integrated services with dynamic bandwidth sharing among the
services and asymmetrical data rate;
• IP mobility and virtual private networks (VPN) for the individual
passengers in the mobile network; authentication, admission and accounting
(AAA) in the mobile network, especially taking into account the necessity to
support different pricing concepts for each passenger in the mobile network and
the interaction of airline, satellite provider, aircom service provider and
terrestrial service providers.
Satellite connection
Connection to telecom networks is considered to be achieved by
satellites with large coverage areas especially over oceanic regions during
long-haul flights. The service concept needs to take into account today's
peculiarities of satellite communications, thus it must cope with the available
or in near future available satellite technology, and interworking must be
performed at aircraft interface level with the satellite segment,
• Only restricted satellite data rates will be available in the near
future; thus the bandwidth that is requested by standard interfaces of the
wireless standards needs to be adapted to the available bandwidth (typically:
432 kb/s in down- link, 144 kb/s up-link (Inmarsat B- GANTM), or 5 Mb/s in
down-link, 1.5 Mb/s in up-link (Connexion by Boeing)). Furthermore, dynamic
bandwidth management is needed to allocate higher bit rates from temporarily
unused services to other service-
• Currently, few geostationary satellites such as the Inmarsat fleet are
available for two-way communications, that cover the land masses and the
oceans. Ku-band may be used on a secondary allocation basis for aeronautical
mobile satellite services (AMSS) but bandwidth is scarce and coverage is mostly
provided over continents. K/Ka-band satellites will be launched in the near
future, again here continental coverage is mainly intended. The scenario must
thus consider
the use of different
satellite systems, which will probably force the support of different service
bearers, andhandover between
satellite systems.
It is assumed that each satellite segment is connected via terrestrial
wide area networks or via the IP backbone to the aircom service provider.
• Asymmetrical data rates in satellite up- and down-links, that may also
be caused to operate in conjunction with different satellites systems for up-
and down-link. The service portfolio in the cabin and the service integration
needs to cope with this possibility.
Service Integrator
The different wireless access services of UMTS, W-LAN and Bluetooth
require an integration of the services over the satellite. The central part of
the service portfolio provisioning is the service integrator (SI), cf. Figure
3. The service integrator will provide the interfaces for the wireless and
wired service access points in the cabin, as well as the interface to the
terrestrial networks at aircom provider site. All services will be bundled and
transported between a pair of Service Integrators. It performs the
encapsulation of the services and the adaptation of the protocols.
The SI multiplexer is envisaged to assign variable capacities to the
streams, controlled by a bandwidth manager that monitors also the QoS
requirements of the different service connections. Changes in capacity
assignment must be signaled to the SI at the other communication end. The
heterogeneous traffic stream is then sent to streaming splitter/combiner. This
unit is envisaged to support several satellite segments and to perform handover
between them. Asymmetrical data rates in inbound and outbound directions can be
managed here. Adaptation to the supported satellite segments are done by medium
access controllers (MAC) in a modular manner. Towards the terminal side, the
interfaces of the wireless access standards need to interwork with the
transport streaming of the SI by specific adaptation layers (AL). These ALs
have to be designed according to the analysis of the impact of delay, jitter
and restricted / variable bandwidth on the protocol stack. Buffering (to
compensate delay jumps at handover) and jitter compensation for real-time
services (e.g., voice) must be also provided here,
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