U.S. patent application number 10/869037 was filed with the patent office on 2005-02-03 for method and arrangements for wireless communication in a vehicle.
This patent application is currently assigned to Nokia Corporation. Invention is credited to Kallio, Janne, Sinivaara, Hasse.
Application Number | 20050026608 10/869037 |
Document ID | / |
Family ID | 8566284 |
Filed Date | 2005-02-03 |
United States Patent
Application |
20050026608 |
Kind Code |
A1 |
Kallio, Janne ; et
al. |
February 3, 2005 |
Method and arrangements for wireless communication in a vehicle
Abstract
The present invention provides an operational mode of
communication which adjusts a transmitting power of a cellular
system and a mobile terminal used inside a vehicle, such as an
aircraft, so that the mobile terminals (102) inside the aircraft
camp on the indoor cellular network (100) inside the aircraft and
do not interfere with external cellular networks. This reduces
possible electromagnetic interference with avionics inside the
aircraft, because the transmitted power levels is limited. The
frequency band used by the indoor cellular network can be
determined by the service provider independent of frequency bands
allocated by communication specifications and regulations.
Conventional mobile terminals (102) and conventional base
transceiver stations (104) applying the aircraft profile according
to the invention can be used inside the aircraft while aboard to
communicate with the conventional external cellular networks
(150).
Inventors: |
Kallio, Janne; (Ylojarvi,
FI) ; Sinivaara, Hasse; (Espoo, FI) |
Correspondence
Address: |
WARE FRESSOLA VAN DER SLUYS &
ADOLPHSON, LLP
BRADFORD GREEN BUILDING 5
755 MAIN STREET, P O BOX 224
MONROE
CT
06468
US
|
Assignee: |
Nokia Corporation
|
Family ID: |
8566284 |
Appl. No.: |
10/869037 |
Filed: |
June 15, 2004 |
Current U.S.
Class: |
455/431 ;
455/12.1; 455/427 |
Current CPC
Class: |
H04B 7/18506 20130101;
H04W 52/265 20130101; H04B 7/18563 20130101 |
Class at
Publication: |
455/431 ;
455/012.1; 455/427 |
International
Class: |
H04B 007/185; H04Q
007/20 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 19, 2003 |
FI |
20030929 |
Claims
1. A method for providing an operational mode of wireless
communication between at least one mobile terminal and at least one
first network device inside a vehicle, such as aircraft, the method
comprising steps of: communicating from the mobile terminal
information indicating an operational mode that the mobile terminal
uses for a wireless connection between the mobile terminal and the
first network device inside the aircraft, connecting the mobile
terminal via the first network device inside the aircraft to
wirelessly communicate with a second network device outside the
aircraft, where the wireless connection between the first network
device and the second network device uses an operational mode of
communication capable of communicating with external wireless
networks outside the aircraft, characterized by limiting a
transmitting power value for a wireless connection between the
mobile terminal and the first network device to a limit power
value, selecting said limit power value on the basis of providing a
determined quality of service of the connection and minimizing
interference with external wireless networks, selecting at least
one frequency value to establish a wireless connection between the
mobile terminal and the first network device on the basis of
minimizing the interference effect with external wireless networks,
and configuring the operational mode of communication in the
wireless connection inside the aircraft on the basis of said limit
power value and said frequency value.
2. A method according to claim 1, characterized in that such limit
power value for the wireless connection between the mobile terminal
and the first network device is selected which ensures acceptable
voice and data transmitting quality inside the aircraft.
3. A method according to claim 1, characterized in that such limit
power value for the wireless connection between the mobile terminal
and the first network device is selected which ensures that network
devices of external wireless networks are unable to receive a
connection request sent by the mobile terminal inside the
aircraft.
4. A method according to claim 3, characterized in that such limit
power value for the wireless connection between the mobile terminal
and the first network device is selected which ensures that network
devices of external wireless networks are unable to receive a
location update request sent by the mobile terminal inside the
aircraft.
5. A method according to claim 1, characterized in that the
selected limit power value for the wireless connection between the
mobile terminal and the first network device overrules a
transmitting power command given by any external wireless
network.
6. A method according to claim 1, characterized in that the step of
selecting at least one frequency value comprises further steps of:
detecting frequencies from a group of available frequencies inside
the aircraft for transmission between the mobile terminal and the
first network device, and based on the detecting determining at
least one frequency value which provides least interference with
external wireless networks.
7. A method according to claim 6, characterized in that the group
of available frequencies excludes frequencies used in external
wireless networks.
8. A method according to claim 6, characterized in that the group
of available frequencies excludes frequencies used in a GSM, PCS or
other frequency bands compliant with communication
specifications.
9. A method according to claim 6, characterized in that the step of
detecting frequencies from a group of available frequencies is run
when establishing the wireless connection between the mobile
terminal and the first network device.
10. A method according to claim 6, characterized in that the step
of detecting frequencies from a group of available frequencies is
run continuously, and on the basis of detecting several frequency
values are used for transmission between the mobile terminals and
the first network devices.
11. A method according to claim 10, characterized in that a
handover is performed to a number of mobile terminals, wherein the
handover is performed first to the mobile terminals and the network
devices using the frequency value causing most interference among
selected frequency values.
12. A method according to claim 6, characterized in that the step
of detecting comprises a further step of relaying information
indicating the selected frequency value of communication from the
first network device to the second network device.
13. A method according to claim 6, characterized in that the step
of detecting comprises a further step of relaying information
indicating the need of change the selected frequency value of
communication from the first network device to the second network
device.
14. A method according to claim 1, characterized in that the step
of configuring the operational mode of communication comprises
further steps of: establishing a wireless connection between the
mobile terminal and the first network device inside the aircraft,
and relaying information indicating the selected operational mode
of communication from the first network device to a second network
device and vice versa.
15. A method according to claim 14, characterized in that the step
of establishing the wireless connection comprises a step of
selecting an operational mode of communication in a wireless
network inside the aircraft when the mobile terminal is switched on
inside the aircraft, and after the selection of the operational
mode the wireless connection is established.
16. A method according to claim 14, characterized in that the step
of establishing the wireless connection comprises a step of
displaying on the mobile terminal an operational mode of
communication in a wireless network inside the aircraft when the
mobile terminal is switched on inside the aircraft.
17. A method according to claim 14, characterized in that the step
of establishing the wireless connection comprises a step of
transmitting a RACH burst using the limit power value from the
mobile terminal to the first network device when the mobile
terminal is switched on.
18. A method according to claim 14, characterized in that the step
of establishing the wireless connection comprises a step of
disabling a wireless connection between the mobile terminal and the
first network device using the operational mode of the external
network.
19. A method according to claim 18, characterized in that the step
of establishing the wireless connection comprises a step of sending
a location update rejection from the mobile terminal and the first
network device as a reply to a location update request from the
external wireless network.
20. A method according to claim 14, characterized in that the step
of relaying information indicating the selected operational mode
comprises signalling information from the first network device and
the second network device and vice versa.
21. A method according to claim 14, characterized in that the step
of relaying information indicating the selected operational mode
comprises a RACH burst using the limit power value from the first
network device and the second network device and vice versa.
22. A method according to claim 1, characterized in that the method
is compliant with at least one of the following communication
specifications: GSM, PCN, PCS, HSCSD, GPRS, EDGE, CDMA, WCDMA,
Bluetooth, UMTS, Teldesic, Iridium, Inmarsat and WLAN.
23. A method according to claim 1, characterized in that the
wireless connection between the mobile terminal and the first
network device is established by a wireless network inside the
aircraft.
24. A system for wirelessly communicating information between a
mobile terminal inside a vehicle, such as an aircraft, and a first
network device inside the aircraft, the system comprising: at least
one mobile terminal for wirelessly communicating with the first
network device information indicating an operational mode that is
used for a wireless connection between the mobile terminal and the
first network device inside the aircraft, at least one first
network device for wirelessly connecting the mobile terminal to
communicate with a second network device outside the aircraft where
the connection between the first network device and the second
network device uses an operational mode of wireless communication
capable of communicating with external wireless networks outside
the aircraft, at least one second network device outside the
aircraft for wirelessly communicating with external wireless
networks, characterized in that the mobile terminal is arranged to
limit a transmitting power value for a wireless connection with the
first network device to a first limit power value, wherein said
first limit power value is based on quality of service of the
connection and amount of interference with external wireless
networks, the first network device is arranged to limit a
transmitting power value for a wireless connection with the mobile
terminal to a second limit power value wherein said second limit
power value is based on achieving a determined quality of service
of the connection and minimizing the amount of interference with
external wireless networks, the system is arranged to select at
least one frequency value to establish a wireless connection with
the mobile terminal which frequency value is based on providing
least interference with external wireless networks, and the system
is arranged to configure the operational mode of wireless
communication in the wireless connection inside the aircraft on the
basis of said limit power values and said frequency value.
25. A system according to claim 24, characterized in that at least
one frequency value is selected, the system inside the aircraft
comprises: means for detecting frequencies from a group of
available frequencies for transmission between the mobile terminal
and the first network device, and based on the detecting means for
calculating at least one frequency value which provides least
interference with external wireless networks.
26. A system according to claim 24, characterized in that the first
network device comprises an antenna for wireless information
transmission inside the aircraft.
27. A system according to claim 26, characterized in that the first
network device comprises a leaky cable for wireless information
transmission inside the aircraft, where the leaky cable is routed
from front to rear inside the aircraft.
28. A system according to claim 24, characterized in that the
configuring the operational mode of wireless communication is
arranged to: establish a wireless connection between the mobile
terminal and the first network device inside the aircraft, and
relay information indicating the selected operational mode of
wireless communication from the first network device to the second
network device, and vice versa.
29. A system according to claim 28, characterized in that the means
for relaying information comprises a first switching module
associated to the first network device to be connected via a
wireless connection link to a second switching module which locates
associated to the second network device for transmitting
information indicating the selected operational mode.
30. A system according to claim 29, characterized in that the
wireless connection between the first switching module and the
second switching module is routed via a satellite link.
31. A system according to claim 30, characterized in that the first
switching module comprises a first emulator and the second
switching module comprises a second emulator, where the first
emulator emulates to the first network device that the first
network device is wirelessly connected to the second network device
while there is not any transmission between the first and second
network devices, and the second emulator emulates to the second
network device that the second network device is wirelessly
connected to the first network device while there is not any
transmission between the first and second network devices.
32. A system according to claim 24, characterized in that the first
network device is a base transceiver station (BTS) and the second
network device is a base station controller (BSC).
33. A system according to claim 24, characterized in that the
wireless connection between the mobile terminal and the first
network device is established by a wireless network inside the
aircraft.
34. A system according to claim 24, characterized in that the
system is compliant with at least one of the following
communication specifications: GSM, PCN, PCS, HSCSD, GPRS, EDGE,
CDMA, WCDMA, Bluetooth, UMTS, Teldesic, Iridium, Inmarsat and
WLAN.
35. A first network device for communicating information via a
wireless connection to a mobile terminal inside a vehicle, such as
an aircraft, and for communicating information via wireless
connection link to a second network device capable of communicating
in external wireless networks outside the aircraft, the first
network device comprising: means for transmitting information to
the mobile terminal in a wireless network, the information
indicating an operational mode that the mobile terminal uses for a
wireless connection between the mobile terminal and the first
network device, means for connecting the mobile terminal inside the
aircraft to wirelessly communicate with a second network device
outside the aircraft, where the wireless connection between the
first network device and the second network device uses an
operational mode of wireless communication capable of communicating
with external wireless networks, characterized in that the first
network device is arranged to: limit a transmitting power value for
a wireless connection with the mobile terminal to a limit power
value which provides at least a determined a quality of service of
the connection and a minimum of interference with external wireless
networks, select at least one frequency value to establish a
wireless connection with the mobile terminal which frequency
provides minimum interference with external wireless networks, and
configure the operational mode of wireless communication in the
wireless connection inside the aircraft on the basis of said limit
power value and said frequency value.
36. A first network device according to claim 35, characterized in
that the first network device comprises an antenna for wireless
information transmission inside the aircraft.
37. A first network device according to claim 36, characterized in
that the first network device comprises a leaky cable for wireless
information transmission inside the aircraft, where the leaky cable
is routed from front to rear inside the aircraft.
38. A first network device according to claim 35, characterized in
that the configuring the operational mode of wireless communication
is arranged to: establish a wireless connection between the mobile
terminal and the first network device inside the aircraft, and have
means for relaying information indicating the selected operational
mode of wireless communication from the first network device to the
second network device, and vice versa.
39. A first network device according to claim 38, characterized in
that the means for relaying information comprises a first switching
module to be connected via a wireless connection link to a second
switching module which locates associated to the second network
device for transmitting information indicating the selected
operational mode.
40. A first network device according to claim 39, characterized in
that the first switching module comprises a first emulator to
emulate to the first network device that the first network device
is wirelessly connected to the second network device while there is
not any transmission between the first and second network
devices.
41. A first network device according to claim 35, characterized in
that the wireless connection between the mobile terminal and the
first network device is established by a wireless network inside
the aircraft.
42. A mobile terminal for communicating information wirelessly to
at least one first network device inside an aircraft, the mobile
terminal comprising: a transmitter for transmitting information to
the first network device in a wireless network, the information
indicating an operational mode that the mobile terminal uses for a
wireless connection between the mobile terminal and the first
network device, characterized in that the mobile terminal further
comprises means for transmitting the information to the first
network device using an operational mode of wireless communication
to limit a transmitting power value to a limit power value which
provides at least a determined quality of service of the connection
and a minimum interference with external wireless networks outside
the aircraft, means for receiving a command from the first network
device indicating an operational mode of wireless communication and
indicating a frequency value to establish a wireless connection to
the first network device which frequency value provides minimum
interference with external wireless networks, and means for
selecting an operational mode of wireless communication configured
in the wireless connection inside the aircraft on the basis of said
limit power value and said frequency value.
43. A mobile terminal according to claim 42, characterized in that
it comprises means for displaying said selected operational
mode.
44. A mobile terminal according to claim 42, characterized in that
a menu and a key is used to select and a display unit is used to
indicate the operational mode of wireless communication for the
wireless connection inside the aircraft.
45. A mobile terminal according to claim 42, characterized in that
the wireless connection between the mobile terminal and the first
network device is established by a wireless network inside the
aircraft.
Description
TECHNICAL FIELD OF THE INVENTION
[0001] The present invention relates to the field of mobile radio
communication systems in cellular wireless networks, and more
particularly to mobile communication systems using wireless network
cells inside a vehicle, such as an aircraft, other airborne vessel,
ship or train while aboard.
BACKGROUND OF THE INVENTION
[0002] The use of mobile phones is restricted inside airline
carriers due to a possibility that the transmission of a mobile
phone could cause interference problems.
[0003] The Federal Communications Commission (FCC), which regulates
the use of wireless mobile phones aboard aircrafts while they are
in flight, has since 1988 barred the use of cellular phones in the
air because of their potential to interfere with terrestrial
cellular calls. This regulation names only mobile phones operating
in the 850 MHz cellular band, but the airlines have the authority
to decide about the use of any type of mobile phone during flight.
The Federal Aviation Administration (FAA) recommends for its part
that the use of a cellular phone is unauthorized during taxiing,
take-off and landing.
[0004] Some other problems have also arisen due to relatively high
transmitting power of wireless systems and electromagnetic
interference thereof. Anecdotal instances suggest that the use of
the mobile phone on an aircraft might interfere with the navigation
equipment and other avionics or communications equipment on the
aircraft. Another problem is that due to the height of an airborne
aircraft the wireless network coverage does not cover the mobile
phones on an airborne aircraft because the terrestrial wireless
networks are designed for lateral transmission and reception of
radio frequency signals and for relatively slow moving vehicles and
pedestrians. One solution for this problem is to provide a base
station and thus an internal cell inside the aircraft. However,
other problems may arise when there exists a wireless cell inside
an aircraft and at the same time there are available powerful
external wireless cells. There is, for example, a problem to keep
all the mobile phones inside the aircraft exclusively camped to the
cell inside the aircraft.
[0005] Although the use of the mobile phone from an aircraft might
be possible at some altitudes, it does not operate within the
considerations designed and built about call handovers between
adjacent terrestrial cells. Due to the high velocity of the
airborne aircraft an equally strong RF signal from the mobile phone
may be picked up on multiple base stations on the ground and the
network is unable to process a normal call handover procedure. This
might result in an operational malfunction, might cause calls to be
frequently dropped and could actually cause base stations to shut
down. This might also jam calls of other users covered by the same
terrestrial base stations.
[0006] Today wireless communication services for passengers are
provided in aircrafts by dedicated phones that are installed at
each seat and wired to the central transmitter/receiver in the
aircraft. This network of phones operates on its own frequency band
which differs from other frequency bands used for avionics. To run
this service a service provider must provide base stations on the
ground to which RF signals are transferred in the vertical
direction i.e. a skyward transmission and reception. To allow
smooth handovers in the air these base stations must cover a much
larger territory than the base stations of the terrestrial wireless
network and antennas must be focussed skywards. Service users must
use the dedicated phones provided by the service provider and users
having personal mobile phones in the aircraft must keep their
equipment switched off.
[0007] As more and more people carry and use mobile phones, it may
not be justified to maintain areas where their use is prohibited
because it increases the tendency for misuse and to contravene
rules unintentionally or on purpose.
SUMMARY OF THE INVENTION
[0008] In this application the following terms are used. The term
"indoor" relates to the objects which are located or used inside
the aircraft independent of the location of the aircraft whether
being in the air or on the ground. The indoor mobile terminal
relates to the wireless mobile terminal equipment that is used
inside the aircraft. The indoor mobile terminal is typically a
personal terminal equipment carried and occupied by its user (also
outside the aircraft). The indoor connection or network relates to
the wireless connection or network and to its components that are
located or are used inside the aircraft. In the same sense, the
term "external" relates to the objects which are located or used
outside the aircraft. The external mobile terminal relates to the
wireless mobile terminal that is located and is used outside the
aircraft. I.e. the same mobile terminal may be the indoor mobile
terminal or the external mobile terminal depending on whether it is
used inside the aircraft or outside the aircraft. The external
network relates to the wireless network and to its components that
are located outside the aircraft. As a clarification it shall be
noticed that the indoor networks and external networks are fully
capable of communicating with each other.
[0009] An object of the invention is to solve the problems related
to prior art and thus provide an aircraft profile for wireless
communication via a wireless connection or network inside the
aircraft and a mobile terminal capable of communicating with a
external terrestrial wireless network, in which the mobile terminal
can be switched on to be used inside an aircraft without
interfering with navigation and other avionics equipment, and
without being jammed by operation of unwanted external wireless
networks outside the aircraft.
[0010] The object of the invention is fulfilled by providing an
aircraft profile which adjusts a transmitting parameter of a
wireless connection or network and a mobile terminal inside the
aircraft to a limit value which is sufficiently high to guarantee
acceptable voice and data transmission quality inside the aircraft
and which is sufficiently low not to be interfered with external
wireless networks. The limit value of the transmitting parameter
adjusted by said aircraft profile according to the invention
overrules commands given by external wireless networks in relation
to the transmitting parameter of indoor mobile terminals.
[0011] In accordance with a first aspect of the invention there is
provided a method for providing an operational mode of wireless
communication between at least one mobile terminal and at least one
first network device inside the aircraft, the method comprising
steps of: communicating from the mobile terminal information
indicating an operational mode that the mobile terminal uses for a
wireless connection between the mobile terminal and the first
network device inside the aircraft; connecting the mobile terminal
via the first network device inside the aircraft to wirelessly
communicate with a second network device outside the aircraft,
where the wireless connection between the first network device and
the second network device uses an operational mode of communication
capable of communicating with external wireless networks outside
the aircraft; is characterized by: limiting a transmitting power
value for a wireless connection between the mobile terminal and the
first network device to a limit power value which ensures a quality
of service of the connection and does not interfere with external
wireless networks; selecting at least one frequency value to
establish a wireless connection between the mobile terminal and the
first network device which frequency value ensures the least
interference with external wireless networks; and configuring the
operational mode of communication in the wireless connection inside
the aircraft on the basis of said limit power value and said
frequency value.
[0012] In accordance with a second aspect of the invention there is
provided a system for wirelessly communicating information between
a mobile terminal inside an aircraft and a first network device
inside an aircraft, the system comprising: at least one mobile
terminal for wirelessly communicating with the first network device
information indicating an operational mode that is used for a
wireless connection between the mobile terminal and the first
network device inside the aircraft; at least one first network
device for wirelessly connecting the mobile terminal to communicate
with the second network device outside the aircraft where the
connection between the first network device and the second network
device uses an operational mode of wireless communication capable
of communicating with external wireless networks outside the
aircraft; at least one second network device outside the aircraft
for wirelessly communicating with external wireless networks; is
characterized in that: the mobile terminal is arranged to limit a
transmitting power value for a wireless connection with the first
network device to a limit power value based on determined quality
of service of the connection and minimum interfere with external
wireless networks; the first network device is arranged to limit a
transmitting power value for a wireless connection with the mobile
terminal to a limit power value which provides at least a
determined quality of service of the connection and minimizes
interference with external wireless networks; the system is
arranged to select at least one frequency value to establish a
wireless connection with the mobile terminal which frequency value
ensures the least interference with external wireless networks; and
the system is arranged to configure the operational mode of
wireless communication in the wireless connection inside the
aircraft on the basis of said limit power value and said frequency
value.
[0013] In accordance with a third aspect of the invention there is
provided a first network device for communicating information via a
wireless connection to a mobile terminal inside an aircraft, and
for communicating information via wireless connection link to a
second network device capable of communicating in external wireless
networks outside the aircraft, the first network device comprising:
means for transmitting information to the mobile terminal in a
wireless network, the information indicating an operational mode
that the mobile terminal uses for a wireless connection between the
mobile terminal and the first network device; means for connecting
the mobile terminal inside the aircraft to wirelessly communicate
with a second network device outside the aircraft, where the
wireless connection between the first network device and the second
network device uses an operational mode of wireless communication
capable of communicating with external wireless networks; is
characterized in that the first network device is arranged to:
limit a transmitting power value for a wireless connection with the
mobile terminal to a limit power value which provides at least a
determined quality of service of the connection and does minimizes
interference with external wireless networks; select at least one
frequency value to establish a wireless connection with the mobile
terminal which frequency value causes minimum interference with
external wireless networks; and configure the operational mode of
wireless communication in the wireless connection inside the
aircraft on the basis of said limit power value and said frequency
value.
[0014] The present invention provides an aircraft profile which
adjusts a transmitting power of a cellular system and a mobile
terminal used inside the aircraft to a limit value that the mobile
terminals inside the aircraft camp the indoor cellular network
inside the aircraft and do not interfere with external cellular
networks. This limit value of transmitting power in the indoor
cellular network also reduces possible electromagnetic interference
with avionics inside the aircraft, because the transmitted power
levels are low. The frequency band used by the indoor cellular
network can be determined by the service provider (or operator)
independent of frequency bands allocated by the countries in whose
airspace the aircraft is flying or to which the aircraft is
landing. Conventional mobile terminals and conventional base
transceiver stations applying the aircraft profile according to the
invention can be used inside the aircraft while aboard to
communicate with the conventional external cellular networks.
[0015] Some embodiments of the invention are described in
independent claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] Some embodiments of the invention will be described in
detail below, by way of example only, with reference to the
accompanying drawings, of which
[0017] FIG. 1a shows an embodiment of the wireless communication
system according to the invention,
[0018] FIG. 1b shows an embodiment of the mobile terminal according
to the invention,
[0019] FIG. 1c shows an embodiment of the first network device
according to the invention,
[0020] FIG. 1d shows an embodiment of the second network device
according to the invention,
[0021] FIG. 2 shows an embodiment of the method for providing an
aircraft profile mode of wireless communication in a point of view
a mobile terminal,
[0022] FIG. 3 shows an embodiment of the method for providing an
aircraft profile mode of wireless communication according to the
invention,
[0023] FIG. 4 shows an example of a power level optimization in a
method for providing an aircraft profile mode of wireless
communication according to the invention,
[0024] FIG. 5 shows an example of an indoor frequency detection in
a method for providing an aircraft profile mode of wireless
communication according to the invention, and
[0025] FIG. 6 shows an other example of an indoor frequency
detection in a method for providing an aircraft profile mode of
wireless communication according to the invention.
DETAILED DESCRIPTION
[0026] The present invention is generally directed to an apparatus
and a method for providing a preferable operational mode of
wireless communication for a wireless connection between
communication devices such as a mobile terminal (MS) and a first
network device, where the devices communicate via a wireless
connection inside an aircraft, called an indoor connection in this
description, or wireless network inside an aircraft, called an
indoor network in this description. A preferable operational mode
of wireless communication inside the aircraft, called an aircraft
profile in this description, shall limit a transmitting power of
the devices communicating via the indoor connection or indoor
network to a limit power value, wherein the transmitting power is
high enough to guarantee an acceptable quality for voice and data
transmission inside the aircraft. At the same time the transmitting
power shall be low enough not to camp on a network device outside
the aircarft, called an external network device in this
description. Further, the limit power value of the transmitting
power shall overcome the power commands sent by mobile terminals
wirelessly connected to an external network and network devices
wirelessly connected to an external network.
[0027] Another part of providing the aircraft profile is to find
the best frequency value or frequencies values to be used for
wireless communication inside the aircraft. The optional selected
frequency value or frequencies values do have the least
interference with navigation, avionics and other electrical devices
used inside the aircraft and do not interfere with external
frequencies used in external networks outside the aircraft. On the
basis of the selected limit power value and the selected frequency
value(s) the aircraft profile is modified to be the operational
mode of wireless communication inside the aircraft comprising at
least one mobile terminal and at least one first network device
inside the aircraft.
[0028] By providing a preferable aircraft profile mode of wireless
communication for a wireless connection between an indoor mobile
terminal and an indoor first network device, where the devices
communicate via an indoor connection or indoor network, there are
many advantages achieved. Firstly, disturbances between indoor
network and other indoor electronic devices and systems are
minimized. Secondly, all indoor mobile terminals and indoor network
devices are reliably camped on the indoor network without
interference with external networks. And thirdly, it is always
possible to use in indoor connection or indoor network the
frequencies having the least interference without a need to know
any information about external network topology and frequencies
used in those external networks. The frequencies used inside the
aircraft may be selected independently of any specifications and
regulatory orders of the authorities. The fourth advantage is that
it is possible to cover the indoor mobile terminal inside the
aircraft while in the air by external, typically terrestrial
wireless networks via a satellite link between the indoor network
device and the external network device on the ground.
[0029] FIG. 1a shows an embodiment of the wireless cellular
communication system according to the invention in which
information is transferred between a mobile terminal 102 and a
first network device 104 in an indoor cell or network 100 inside an
aircraft. The mobile terminal communicates with the first network
device information indicating an operational mode used for a
connection between said devices. The mobile terminal 102 is
connected via the first network device 104 to the second network
device 120 outside the aircraft and the second network device is
capable of communicating with external networks 150 using
operational modes for wireless communication in accordance with
relevant specifications and regulations. The transmission from the
first network device 104 of the indoor cell or indoor network to
the second network device 120, and vice versa, is routed via a
satellite link 140 using antennas 112 and 122.
[0030] According to the invention one or more first network devices
104 may be located inside the aircraft, each of them forming own
indoor cell and each of them forming its own connection to the
second network devices 120. If only one first network device 104 is
located inside the aircraft it will establish a indoor cell 100,
but if two or more first network devices are located inside the
aircraft they will establish a network 100 which is composed of two
or more cells.
[0031] According to the invention the indoor network 100 and the
external network 150 are compatible with each other. Preferably,
both networks are compliant with at least one of the following
communication specifications: GSM (Global System for Mobile
communications), PCN (Personal Communication Network), PCS
(Personal Communication System), HSCSD (High Speed Circuit Switched
Data), GPRS (General Packet Radio Service), EDGE (Enhanced Data
rates for GSM Evolution), CDMA (Code Division Multiple Access),
WCDMA (Wide band CDMA), Bluetooth, UMTS (Universal Mobile
Telecommunications System), Teldesic, Iridium, Inmarsat and WLAN
(Wireless Local Area Network). Mobile terminals, network devices
and other communication devices in external networks 150,
preferably terrestrial cellular networks, communicate with each
other using operational modes which are determined in relevant
communication specifications and regulations. The indoor mobile
terminals 102 and the indoor network devices 104 in the indoor
network 100 communicate with each other using the aircraft profile
provided according to the invention.
[0032] In the preferred embodiment the mobile terminal 102 is a
mobile station is a of a cellular network inside the aircraft, the
first network device 104 is a base tranceiver station (BTS) of a
cellular network inside the aircraft and the second network device
120 is a base station controller (BSC) of a cellular network
outside the aircraft.
[0033] One example of a wireless network to be used in the wireless
communication system according to the invention is the GSM network.
The indoor network 100 according to the invention may be operated
by any telecom operator who, in addition to the indoor network
devices 104, fits up the system with external network devices such
as mobile switching center (MSC) 130, base station controller (BSC)
120 and network management system 160, and has access to SS7
(Signalling System 7) networks 150. The telecom operator must also
have a roaming agreement with a terrestrial GSM operator, as well
as transmission agreements with satellite communication (satcom)
operators or service providers.
[0034] FIG. 1a shows an embodiment of the wireless cellular
communication system according to the invention in which
information is transferred between a mobile station (MS) 102 and a
base tranceiver station (BTS) 104 in an indoor cell 100 inside an
aircraft. The MS communicates with the BTS information indicating
an operational mode used for a connection between the MS and the
BTS. The MS 102 is wirelessly connected via the BTS 104 to base
station controller (BSC) 120 being located outside the aircraft and
the BSC is capable of communicating with external networks 150
using operational modes for wireless communication in accordance
with relevant specifications and regulations. The transmission from
the BTS 104 of the indoor cell to the BSC 120, and vice versa, is
routed via a satellite link 140 by means of an antenna 112
connected to the BTS and an other antenna 122 connected to the BSC.
According to one embodiment of the invention the MS 102 is
wirelessly connected via the BTS 104 to base station controller
(BSC) 120 outside the aircraft where the BSC is capable of
communicating with terrestrial GSM/GPRS networks 150 using
operational modes for wireless communication in accordance with
terrestrial GSM/GPRS specifications and regulations. The signalling
is controlled by a network management system 160 (NMS).
[0035] The indoor cell 100 comprises an antenna unit 106 connected
to BTS 104 to transmit and receive information wirelessly inside
the indoor cell. According to one preferred embodiment of the
invention a leaky cable that is routed from front to rear inside
the aircraft is used as an antenna 106. The transmitting power
level inside the aircraft can be limited to a limit power value
which guarantee a uplink range from the indoor BTS to the indoor MS
is 5-10 meters inside the aircraft. The use the leaky cabel 106
routed from front to rear means that the uplink range is always
less than 10 meters independent of the size of the aircraft.
[0036] The air frame of the aircraft forms a sealed metal frame, a
Faraday cage, which weakens the signal passing through frame and
shields from electromagnetic interference coming outside the air
frame. This enables the use of limited transmitting power levels
inside the aircraft because less interference to external radio
networks occur from sources inside the aircraft. The transmitting
power of the MS and the BTS is controlled by the power control
functionality in the radio networks. The power control is based on
received field intensity measurements (R.times.Lev) and received
signal quality measurements (R.times.Qual) made by the MS and the
BTS. Typically, the specifications of the radio networks define the
minimum and maximum transmitting power levels and the transmitting
power varies according to the measured R.times.Lev and R.times.Qual
values.
[0037] In one embodiment of the invention a transmitting power
level is limited so that a minimum transmitting power will be
approximately the minimum power level of the GSM transmitting power
and the maximum transmitting power level will be just a little bit
higher than the minimum power level. After an iteration process
described more detail in FIG. 4, there will be a limited
transmitting power value, called a limit power value, to enable
wireless communication inside the aircraft according to the
invention. I.e. the limit power value is high enough to guarantee
an acceptable quality for voice, data, audio and video transmission
inside the aircraft, and low enough not to camp on external
networks outside the aircarft. When the aircraft profile is
activated in the MS, the limited power value of the aircraft
profile shall always overcome the power commands sent to mobile
terminals wirelessly connected to network. This means, that the MS
camped on the indoor cell will always use in uplink transmission
the limited transmitting power, i.e. the power commands with
transmitting power values exceeding the limit power value will be
overruled by the power settings of the limit power value in the
MS.
[0038] In GSM the network always controls the usage power of the
MS, when MS has an active call. When making the first connection
attempt to network (RACH) in normal conditions the mobile may use
full power. According to the present invention the RACH power would
also be limited according the aircraft profile.
[0039] When a call is active, MS sends measurement reports
(downlink quality and level) in each SACCH (about 2 times/s) to
BTS. BTS adds own measurements (uplink quality and level) to this
message and sends it to BSC. BSC has a power control algorithm that
calculates the right power for the MS. The power control message is
then sent via BTS to MS. PC algorithm may adjust also the BTS
power, but typically it is kept static.
[0040] It is considered a preferred solution to have the power
control algorithm located in the BSC, although the power control
algorithm could also in theory locate in the BTS system in the
aircraft. This would require some modification in BSC side, but the
benefit would be, that the measurement reports and power commands
would not need to be sent via the satellite link. If the power
control algorithm is run in the aircraft, it is also useful to run
the handover algorithm in the aircraft. This would mean, that the
handover, i.e. having an active call, could be made only inside the
aircraft from one inside cell to another and the external usage is
possible only by deactivating the aircraft profile.
[0041] The MS acting in aircraft profile shall limit its power
level in first attempt and later when connected, although the
network would try to command to increase the MS power over the
limit. By doing this external network does not hear the MS
connection attempts and on the other hand the MS power level is
always on the safe side even if the indoor network would try to
increase the power over the limit because of e.g. malfunction or
parameter configuration error.
[0042] The limit power value is part of the aircraft profile and is
included in a power control message transferred between the indoor
MS 102 and the indoor BTS 104. It also limits the uplink range to
5-10 meters. For example, the MS 102 scans in the idle mode calls
from the BTS 104 by monitoring paging channels (PCH) and when the
MS indentifies its own identity information from the paging channel
information the MS will send to the BTS a random access channel
(RACH) signal using the limited transmitting power. Then the BTS
knows that this MS is allowed to access to the indoor network 100
and the connection is established. Also a location area update (LU)
signal is transmitted using the limited power by the MS. In case
the MS identifies PCH calls from any external network cell, the
RACH signal it sends to the external cell will be transmitted using
the limited transmitting power. The external cell can't hear the
RACH signal, because the uplink range is limited to 5-10
meters.
[0043] FIG. 1a shows a detector unit 118 to find an optional
frequency value or values used inside the aircraft having the least
interference with navigation, avionics and other electrical devices
to inside use and not having interference with external frequencies
used in external networks outside the aircraft. The detector unit
118 is freely located anywhere inside the aircraft and it is
connected to the BTS. The detector unit detects frequencies from a
group of available frequencies for transmission between the MS and
the BTS, and sends a list of frequency values to have the least
interference to a CPU 111 of the BTS 104 as shown in FIG. 1c. To a
memory 113 of the CPU 111 is stored threshold values for
permissible interference values and specified frequencies of
external networks. Based on the list of detected frequencies the
CPU 111 calculates at least one frequency value which ensures the
least interference with external wireless networks and electrical
devices on board the aircraft. The CPU rejects the frequencies that
are used in the external networks. Finally, the CPU selects the
frequency value to be a transmitting frequency. Then the CPU
configures the BTS to use the selected frequency.
[0044] When best frequency is calculated in BTS the chosen value
has to be sent to BSC and NMS direction. If the handover algorithm
is run in BSC, the the handover algorithm must have the information
on the used frequency. If the algorithm is run in aircraft, some
modification in BSC is needed, so that it may control BTS and MS,
without having the handover and power control algorithm.
[0045] An alternative version of the frequency selection is that
the inside BTS only sends the measurement data about the measured
frequencies and their signal strengths and the real frequency
selection algorithm is located in BSC, which then sets/changes the
used BTS frequency in normal BTS O&M control manner.
[0046] According to another embodiment of the invention the
detector unit 118 continuously detects frequencies from a group of
available frequencies inside the aircraft. By updating the
frequency value it will be guaranteed that the best actual
frequency value with the least interference is used for
transmission in the indoor network 100. Then the CPU 111 configures
the BTS to use a new frequency value after every frequency
selection made by the CPU of the BTS. In case two or more indoor
cells are available, the MSs using the frequency value to be
changed to a new frequency value, are first handed over to other
indoor cells, and the current cell is shut down. After the
frequency value is changed to be the new frequency value the shut
indoor cell is opened again. In this way, the configuration of the
cell and the change of frequency value is made without dropping
ongoing calls.
[0047] The limit power value and the frequency value(s) provide the
aircraft profile which is included in a signalling information
controlled by a network management system 160 (NMS). The BTS inside
the aircraft tells to the NMS what limit power value and frequency
value the BTS is using. When configuring the aircraft profile mode
of wireless communication the BTS relays the signalling information
indicating the selected aircraft profile to the BSC, and vice
versa. According to one embodiment of the invention the NMS
controlling the signalling messages including information of the
aircraft profile between the indoor MS 102 and the indoor BTS 104
is located in the CPU 111 of the BTS 104. According to another
embodiment of the invention the NMS controlling the signalling
messages including information of the aircraft profile between the
indoor MS 102 and the indoor BTS 104 is located in a memory 117 of
a CPU 115 of the BSC 120 (see FIG. 1d) which means that the
signalling messages including information of the aircraft profile
is routed from the MS via the BTS to the BSC, and vice versa, to
recognize the MSs with the aircraft profile and allow access for
them to the indoor network, and to deny access from the MSs without
the aircraft profile.
[0048] In this way, wrong MSs without the aircraft profile are
rejected when attempting to connect to network. The BTS denies
access from wrong MSs by giving a location update reject message as
a reply to a location update attempt from the wrong MS. The Indoor
BTS system may have its own SW, that recognizes also the location
update message and rejects it, if the attempting mobile does not
indicate using the aircraft profile.
[0049] The configuration of the aircraft profile mode of wireless
communication is established by switching the indoor MS on to the
idle mode and selecting the aircraft profile mode among other
operational modes. The aircraft profile is stored to a memory 105
in association with a CPU 107 of the MS 102 as shown in a block
diagram of the mobile terminal as shown in FIG. 1b. According one
embodiment of the invention the configuration of the MS 102 starts
by selecting from the setup display of the user interface (UI) 103
a menu indicating the aircraft mode and pressing a key 101 to
activate the aircraft profile mode of the wireless connection
between the MS and the BTS 104 inside the aircraft. Another
embodiment is to press a special key 101 simultaneously when the MS
is turned on to have the aircraft profile selected. The aircraft
profile can be switch on and off only after the MS is turned on to
the idle mode to prevent the MS from camping on any external cell
being present inside the aircraft e.g. in airports. Once the
aircraft profile is selected it will overrule all other profile
settings. The display unit 109 of the UI of the MS has the clear
indication that the aircraft profile has been selected.
[0050] The signalling information indicating the selected aircraft
profile mode of wireless communication is relayed from the BTS 104
to the BSC 120, and vice versa. A satellite link connection is used
to route the wireless connection between the BTS and the BSC and
the communication is compliant with external networks, e.g.
terrestrial GSM networks. The satellite link is typically off when
there is no traffic, but the mobile communication presumes a
non-stop connection. To solve the problem the satellite link
connection between the BTS and the BSC comprises switching modules
110, 124 to switch signalling channels and intervals according to
allocations so that the link is off when no traffic occurs. As
shown in FIG. 1c the switching module 110 of the BTS includes an
emulator 114 which emulates to the BTS as if the BTS would be
wirelessly connected to the BSC while there is not any transmission
between the BTS and BSC. In the corresponding way as shown in FIG.
1d the switching module 124 of the BSC includes an emulator 123
which emulates to the BSC as if the BSC would be wirelessly
connected to the BTS while there is not any transmission between
the BTS and BSC. The emulators 114, 123 play the role towards the
BTS and the BSC as if they were wirelessly connected all the time
according to the specifications of GSM networks, while in reality
the satcom link is off if there is no traffic. This is done because
a non-stop satellite connection would be very expensive.
[0051] The emulation functionality is next described in more detail
in the context of satellite handovers.
[0052] Based on the GSM signalling between BTS and BSC the emulator
is used to switch the satellite connection on-off. The emulators
will indicate the activation signalling based on the GSM signalling
messages when calls are initiated and disconnected, paging requests
send to receiving MS. When the MSC-BSC-BTS connectivity can be
disconnected the emulator activates the emulator mode towards BTS
and BSC according the GSM signalling. Secondly the emulator acts as
a connectivity initiator when satellite handovers are taking place.
After satellite handover the aircraft emulator will initiate the
connection into a ground based emulator and satellite Abis
connection will be verified between BTS and BSC node. Emulator will
provide routing mechanism for connecting the BTS and BSC in every
satellite handover.
[0053] In a case where the NSS/BSS system would be regional NSS/BSS
system is duplicated in each Satellite region e.g. US, Europe and
Asia-Pacific. Due to the fact that GSM BTS is typically stationary
and MS mobility and handovers will take place in the network, the
aircraft network BTS will move the BSC areas. This will require
special implementation in the GSM system. Each regional NSS/BSS
will need to be configured in a similar way i.e. duplicate
configuration. Due to stationary system there are limitations in
the BSC-BTS connectivity in the cross-connection. Based on that
fact the BTS should be always connected into the BTS with similar
manner. This requirement sets rules for the system on the BSC side.
Each NSS/BSS region will have its own routing addressing. After the
satellite handover takes place the aircraft side emulator will
initiate the link establishment to the regional BSC and emulator.
The aircraft emulator needs the information into which regional BSC
it will be required to initiate the Abis link. This information can
be received from the aircraft avionics system as satellite region
information. Based on that information the aircraft emulator will
establish a correct routing to the corresponding regional BSC.
[0054] The duplicated NSS/BSS in the system means that each BTS
needs to be configured according the GSM system setup rules to each
BSC. While the BTS is moving and satellite handovers take place the
BTS will change the BSC accordingly. Each BSC needs to have the
information of that BTS (BTS id, Cell id, BCF id etc). When the BTS
changes the BSC after the emulator connection is established the
previous BSC looses the connection to BTS and NMS inactivates the
BTS. In the neighbor region the BTS-BSC connection, transmission
link will be established by the emulators.
[0055] After the transmission link is set up between BTS-BSC, the
BSC will identify the BTS based on its identity parameter and will
perform parameter download to the BTS accordingly. This act could
be identified in the GSM system as Abis connection lost-Abis
connection activated in standard manners. However, what is
different is when the Abis is "lost" i.e. the satellite region is
changed, the BTS changes the BSC i.e. Location area. Therefore when
the BTS is coming into new BSC-location area the BSC will update
the BTS parameter set accordingly. It is required that all the
BTS's are configured into NMS accordingly so that each BTS will be
found in each BSC. When BTS changes the BSC the BTS will be
inactivated in the previous BSC-NMS and activated in the neighbor
BSC-NMS.
[0056] FIG. 2 shows an embodiment of the method for providing an
aircraft profile mode of wireless communication from the point of
view of a mobile terminal, preferably the mobile station (MS). In
step 202 the MS is turned on inside the aircraft and the MS is
switched on to the idle mode. Then in step 204 the setup display of
the MS shows a menu, where the user selects the operational mode to
be the aircraft profile mode. The selection in step 206 can be done
from the menu by pressing a key. The alternative way to select the
aircraft profile is to press a special key simultaneously when the
MS is switched on in step 202. To ensure that the selection of the
operational mode was correct it will be checked in step 208. If the
selection was wrong, e.g. a normal GSM mode was selected, the
operation of the MS is blocked according to step 232 and the MS is
turned off in step 234. The purpose of step 208 is to secure that
only the aircraft profile mode of operation is allowed. Now the MS
is wirelessly connected to the indoor cell and it is in idle mode
of operation. The MS roams only to the neighboring frequencies
available inside the aircraft. Next in step 210 the MS starts
scanning available frequencies inside the aircraft and it roams to
the BTS of the indoor cell. In step 212 the MS is configured to the
aircraft profile according to the message indicating aircraft
profile information from the BTS. If another MS is roaming to the
indoor MS with the aircraft profile settings, it will be checked in
step 214 whether the settings of that other MS are according to the
aircraft profile. If not, the access is denied from that other MS
is step 236.
[0057] Next in step 216 the MS camps on the indoor BTS and the
wireless connection is established. In case there is a need to
change the frequency in step 218 to a new frequency value having
less interference than the previous frequency value, the frequency
is changed in step 244.
[0058] In a GSM system this is arranged in such a way that when the
mobile station is in idle mode camped on one cell, it changes the
cell by itself. The BTS further gives the information about the
neighbour cells and also gives change rules and parameters for the
mobile cell selection algorithm. In the arrangement according to
the present invention, when the frequency of one of the inside BTSs
is changed the idle mode mobiles camped on this cell, will
automatically camp on the neighbour cell. Those MSs that have an
active call then have to be handed over to a neighbour cell,
otherwise the call is dropped. The changed frequency also has to be
informed to other neighbour BTS, i.e. the entity, that sets the BTS
frequency, so that the old frequency can be removed from neighbour
list and new can be added. In the same way, the new frequency
information has to be informed to the handover algorithm, so that
it can make the handover.
[0059] In addition there may be added counters that collect the
information about the frequency changes of the inside BTS. Similar
counters may be added to collect information about inside made
location update rejects and handovers. Typically this counter
information is collected in the NMS system.
[0060] Then in step 242 the MS using the frequency value to be
changed to a new frequency value, is first handovered to the other
indoor cell, and the current cell is shut down. The handover may
here mean either a base station forced handover or camping of a
mobile station according to the neighbour cell information. After
the frequency value is changed to be the new frequency value in
step 244 the shut indoor cell is opened again. Then according to
step 216 the MS camps on the opened indoor cell again. By this way,
the configuration of the cell and the change of frequency value is
made without dropping ongoing calls.
[0061] FIG. 3 shows an embodiment of the method for providing an
aircraft profile mode of wireless communication according to the
invention. In step 300 the indoor cell is activated by turning on
the BTS inside the aircraft. Next the MS is turned on to the idle
mode and the aircraft profile mode is selected according to step
301 as described in FIG. 2 steps 202-210. To generate the aircraft
profile in step 303 the transmitting power of the MS and the BTS
inside the aircraft is limited to a limit power value which ensures
a quality of service of the connection and does not interfere with
external wireless networks. In step 305 the best frequency value or
frequency values ensuring the least interference with external
wireless networks are selected to the indoor cell(s) use. Step 303
is presented more detail in FIG. 4 and step 305 in association to
FIGS. 5 and 6.
[0062] The aircraft profile is then generated in step 307 on the
basis of said limit power value and said frequency value(s) and the
MSs and the BTSs inside the aircraft configured to the aircraft
profile in step 309. The information indicating that the aircraft
profile mode is used is attached to the signalling information
transferred between the MS and the BTS in step 311. Then in step
313 the wireless connection using the aircraft profile is
established inside the aircraft and in step 315 the BTS establishes
a wireless connection to the BSC which is connected to the network
management system (NMS) of external networks. Now the wireless link
from the indoor MS via indoor BTS to the external BSC is
established. The information indicating that the aircraft profile
mode is used is also relayed to BSC and NMS of external networks
attached to the signalling information in step 315.
[0063] To ensure that any wrong MS or external communication device
can't interfere or get access to the indoor cell, it will be
checked in step 317 if any RACH bursts or location update requests
are sent from devices with wrong profile settings. If false
attempts are monitored, the indoor BTS sends the location update
reject message. In step 319 the indoor MS communicates wirelessly
via the indoor BTS cell with another indoor MS or with an external
MS of the external network via the wireless link between the indoor
BTS and the BSC to be connected to the external network.
[0064] It is noted that in a GSM system it is also possible to
adjust the transmission power level of the mobile station with
SYSTEM INFO messages that are transmitted on the broadcast channel
BCCH. This message includes a parameter MS-TX-ALLOWED that informs
the mobile station the maximum allowed transmission power for the
transmission for a mobile station. In standard systems this
parameter is generally kept at the maximum value in order to secure
that the RACH burst can be received, but a smaller parameter could
be used as well. This procedure is, however, different from using
an aircraft profile that is given controlled by the BTS because
using the aircraft profile is independent on the settings of the
BTS in the network. So even if the transmission power in the cell
inside the aircraft would be adjusted to maximum by mistake, the
mobile station would still transmit on a smaller power thus
decreasing the probability that the RACH would be received by
external BTSs.
[0065] FIG. 4 shows an example of a power level optimization in a
method for providing an aircraft profile mode of wireless
communication according to the invention. FIG. 4 presents the step
303 of FIG. 3 more detail. In step 401 the transmitting power
limitation process is started to generate the aircraft profile for
indoor network communication. First a minimum transmitting power
value is selected depending on specifications of the external
network to be compliant with the indoor network. In one embodiment
of the invention a transmitting power level is first limited so
that a minimum transmitting power will be approximately the minimum
power level of the GSM transmitting power in step 403. If the first
selected transmitting power value does not ensure acceptable voice,
audio, video and data transmitting quality between the MS and the
BTS inside the aircraft as determined in step 405, the transmitting
power level is increased a little bit according to step 406. Then
the quality of service is tested again in step 405 and the loop is
repeated so many times as needed until the result is sufficient.
Still when the maximum power value of aircraft profile is reached,
as determined in step 405, this power is not anymore increased
although the required QoS would mean the power should be raised.
The antenna design inside the aircraft shall be done in such a way
that this situation does not occur.
[0066] If the first selected transmitting power value ensures
acceptable voice, audio, video and data transmitting quality inside
the aircraft as determined in step 405, then it is checked in step
407 whether the wireless connection between the indoor MS and the
indoor BTS ensures that external communication devices of external
wireless networks are unable to receive a connection request sent
by the indoor MS inside the aircraft.
[0067] First it is checked whether the QoS is much higher than
necessary, ie. higher than a predetermined upper limit value. If
the QoS value exceeds the upper limit value the transmitting power
is decreased in step 409. This loop of steps 407, 409 is repeated
as long as the QoS value is no longer higher than the upper limit
value. Next it is checked in step 407 whether there is interference
within the cell. If an predetermined interference limit is
exceeded, it is further checked in step 407 whether the QoS clearly
exceeds a predetermined minimum value. If it does, the transmission
power is decreased in step 409. This loop is repeated as long as
the interference is below the limit value or a minimum QoS value
has been reached.
[0068] There is no way to actually detect by the indoor BTS,
whether some indoor MS is still able to connect external BTS, i.e.
is the external BTS able to hear the MS, because there is no link
between the indoor BTS and an external BTS of some external GSM
system. However, since the MS power is limited by the profile to
such a low value, the external network does not detect the inside
low power MS connection attempt (RACH). And further, when the MS
has aircraft profile active, it may disable the connection attempts
to such networks, that do not indicate e.g. in system info
messages, that they are using aircraft profile.
[0069] When the optimal transmitting power level is found, this
optimal transmitting power is selected to be the limit power value
for the aircraft profile in step 411 and the transmitting power
inside the aircraft is limited to this limit power value in step
413. According to one embodiment the connection request sent by the
MS is a RACH burst. According to another embodiment the connection
request sent by the MS is a location update request. The limit
power value for the aircraft profile is selected in step 411.
[0070] FIG. 5 shows an example of an indoor frequency detection in
a method for providing an aircraft profile mode of wireless
communication according to the invention. FIG. 5 presents an
embodiment of the step 305 of FIG. 3 more detail. Here it is
assumed that the indoor BTS is switched on in step 501 just before
before detection process. When the indoor BTS is switched on in
step 501 the detector unit inside the aircraft starts detecting
frequencies from a group of available frequencies inside the
aircraft for transmission between the MS and the BTS according to
step 503. Then, based on the detecting, the CPU of the BTS
calculates the most useable frequency value or frequency values
from a list of frequencies the detector has detected in step 505.
The most useable frequency value(s) ensures the least interference
with external wireless networks.
[0071] Then in step 507 it is checked whether the calculated
frequency value(s) are the same frequencies used in external
wireless networks. If the calculated frequency value(s) are not the
same as used in external networks, the frequency value or these
frequency values are selected to be the frequency value or
frequency values for the aircraft profile in step 509. If the
calculated frequency value(s) are found in step 507 to be the same
as used in external networks, the detector unit inside the aircraft
starts again detecting frequencies from a group of available
frequencies inside the aircraft for transmission between the MS and
the BTS according to step 503. In one embodiment, if the calculated
frequency value(s) are found in step 507 the same as used in a GSM,
PCS or other frequency bands compliant with communication
specifications, the detector unit inside the aircraft starts again
detecting frequencies from a group of available frequencies inside
the aircraft for transmission between the MS and the BTS according
to step 503. The frequency value for the aircraft profile is
selected in step 509.
[0072] FIG. 6 shows another example of an indoor frequency
detection in a method for providing an aircraft profile mode of
wireless communication according to the invention. FIG. 6 presents
another embodiment of the step 305 of FIG. 3 in more detail. Here
it is assumed that the indoor BTS has been switched on in step 601
before the detection process, and the detection process is run
continuously. In step 603 the detector unit inside the aircraft
detects frequencies from a group of available frequencies inside
the aircraft for transmission between the MS and the BTS.
[0073] Then based on the detecting the CPU of the BTS calculates
the most useable frequency value or frequency values from a list of
frequencies the detector has detected in step 605. The most useable
frequency value(s) ensures the least interference with external
wireless networks. After the calculation process there is a list of
the most useable calculated frequency values in step 607. Then
using the loop of steps 609, 611 and 607, it is checked which one
of the calculated frequency values from the list has the least
interference inside the aircraft and the least interference with
external networks.
[0074] The most optimum frequency value is selected in step 613 to
be a frequency value for the aircraft profile. Because the
detection process is continuous, in step 615 it is checked whether
the new frequency value is the same as the current frequency value.
In step 615 it is also checked if only one indoor cell is in use.
If the current frequency value and new frequency value is the same
frequency value the connection maintains unchanged according to
step 616 and the detection process also continues if wanted in step
617. If the current frequency value in step 613 is different than
the new frequency value, it means that the detector has found a new
frequency value with less interference than the current one.
[0075] In one embodiment where only one indoor cell is available
the frequency value of the connection is changed in step 616. In
another embodiment where two or more indoor cells are available a
handover of the connection is performed first to the MS and the BTS
using the most interference frequency value among selected
frequency values according to step 617. The MS connected to the BTS
using the most interference frequency is handed over to other
indoor cell and the BTS is shut down in step 619. Then the shut BTS
is configured with a new frequency value in step 621 and the shut
BTS is opened again in step 623. By this way, the configuration of
the cell and the change of frequency value is made without dropping
ongoing calls. The selection to continue or stop the detection
process is done in step 627. If the detection is stopped the
connection continues with the current frequency value. The
frequency value for the aircraft profile is selected in step
613.
[0076] The invention is not restricted to the embodiments described
above. While a preferred embodiment of the present invention is
disclosed herein for purposes of explanation, numerous changes,
modifications, variations, substitutions and equivalents in whole
or in part should now be apparent to those skilled in art to which
the invention pertains. Accordingly, it is intended that the
present invention be limited only the characteristics and scope of
the hereto appended claims.
[0077] The idea of using emulators can also be used independently,
so it is not in any way restricted to using an aircraft profile but
can also be considered as an independent invention.
[0078] The invention has been described in the context of aircraft
application. However, the invention is not in any way limited to
aircraft use but the idea can also be used in other vehicles such
as bullet trains or ships. The aircraft profile can thus be a
"vehicle profile" for any moving vehicle. The scope of protection
thus also covers such applications.
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