(19)
(11)EP 2 223 448 B1

(12)EUROPEAN PATENT SPECIFICATION

(45)Mention of the grant of the patent:
11.07.2018 Bulletin 2018/28

(21)Application number: 08865320.9

(22)Date of filing:  16.12.2008
(51)Int. Cl.: 
H04H 20/26  (2008.01)
H04H 60/42  (2008.01)
(86)International application number:
PCT/EP2008/067585
(87)International publication number:
WO 2009/080602 (02.07.2009 Gazette  2009/27)

(54)

METHOD FOR SYNCHRONIZING A TUNER, CORRESPONDING DEVICE, RECEIVER COMPRISING THE DEVICE, AND MOBILE PHONE COMPRISING THE RECEIVER

VERFAHREN ZUM SYNCHRONISIEREN EINES TUNERS, ENTSPRECHENDE VORRICHTUNG, EMPFÄNGER MIT DER VORRICHTUNG UND MOBILTELEFON MIT DEM EMPFÄNGER

PROCÉDÉ DE SYNCHRONISATION D'UN TUNER, DISPOSITIF CORRESPONDANT, RÉCEPTEUR COMPORTANT LE DISPOSITIF, ET TÉLÉPHONE PORTABLE COMPORTANT LE RÉCEPTEUR


(84)Designated Contracting States:
AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MT NL NO PL PT RO SE SI SK TR

(30)Priority: 21.12.2007 EP 07291607

(43)Date of publication of application:
01.09.2010 Bulletin 2010/35

(73)Proprietors:
  • PARROT AUTOMOTIVE
    75010 Paris (FR)
  • Antunes, Joseph
    91300 Massy (FR)

(72)Inventors:
  • ANTUNES, Joseph
    F-91300 Massy (FR)
  • DEFOUG, Guillaume
    F-75014 Paris (FR)

(74)Representative: Cabinet Plasseraud 
66, rue de la Chaussée d'Antin
75440 Paris Cedex 09
75440 Paris Cedex 09 (FR)


(56)References cited: : 
WO-A-2007/024824
JP-A- 2006 115 319
  
  • ADRIAN JOHN HORNSBY ET AL: "Network and Service Discovery in Heterogeneous Broadcast Environment" MOBILE AND WIRELESS COMMUNICATIONS SUMMIT, 2007. 16TH IST, IEEE, PI, 1 July 2007 (2007-07-01), pages 1-5, XP031132354 ISBN: 978-1-4244-1662-2
  
Note: Within nine months from the publication of the mention of the grant of the European patent, any person may give notice to the European Patent Office of opposition to the European patent granted. Notice of opposition shall be filed in a written reasoned statement. It shall not be deemed to have been filed until the opposition fee has been paid. (Art. 99(1) European Patent Convention).


Description


[0001] The present invention relates to a method for switching reception from a first service to a second service by synchronizing a tuner during a change of coverage zone.

[0002] Known mobile phones may comprise a DVB-H receiver, which comprises a tuner and a demodulator.

[0003] Several DVB-H networks are often available for a user of the mobile phone. The user may want to switch from a service of a first DVB-H network to a service of a second DVB-H network. The tuner of the DVB-H receiver therefore needs to be synchronized with a DVB-H signal of the second network.

[0004] More precisely, when the mobile phone, and thus the tuner, is located in the first coverage zone, the tuner is synchronized with the first signal emitted over the first coverage zone.

[0005] The second network, intended to be accessed, comprises second coverage zones, covering an broad area. A respective second signal is emitted over each second coverage zone, at a respective frequency. The problem is thus to find an available second signal of the second network.

[0006] A known method for synchronizing the tuner to one of the second signals comprises obtaining all the frequency values of the frequencies of the second signals of the second network, and then scanning all the obtained frequency values, in order to determine available frequencies of the second coverage zone. The tuner is afterwards synchronized with a second signal emitted at one of the available frequencies, generally the second signal having the most power.

[0007] However, scanning all the obtained frequency values is a process that takes time, typically around ten seconds. The user of the mobile phone must therefore wait all that time before accessing to the second service of the second network and this consumes power and uses battery, and the scanning of all the obtained frequencies of all the available networks can take so much time that it consumes a lot of power.

[0008] Document WO 2007/024824 discloses also a switching reception method.

[0009] The invention aims at alleviating the previous problem by proposing a method for synchronizing a tuner that does not always need to scan all the frequency values of the frequencies of the second network.

[0010] Accordingly, the invention relates to a method for switching reception from a first service to a second service different from the first service by synchronizing a tuner according to claim 1.

[0011] Other features of the method are set forth in claims 2 to 4. The invention further relates to a system comprising a tuner and a device for switching reception from a first service to a second service different from the first service by synchronizing the tuner according to claim 5. Other features of the device are set forth in claims 6 to 8. The invention further relates to a DVB-H receiver according to claim 9, and a mobile phone according to claim 10. These features and other of the invention will become apparent by reading the following description of an embodiment of the invention. The description refers to the enclosed drawings, which comprise:
  • a figure 1 representing a mobile phone comprising a DVB-H receiver according to the invention, and
  • a figure 2 being a block diagram of a method for switching reception from a first service to a second service different from the first service by synchronizing a tuner, achieved by the DVB-H receiver of figure 1.


[0012] In the following description, a network means either a particular network conveying a single content, i.e. the same services over the whole coverage area of the network, or a layer of a network that comprises several superposed layers, each layer conveying the same content, i.e. the same services over the whole coverage area of the layer.

[0013] Referring to figure 1, a mobile phone 10 comprises a DVB-H receiver 12.

[0014] The DVB-H receiver 12 comprises a tuner 14, a demodulator 16 and a device 18 for synchronizing the tuner 14.

[0015] The tuner 14 is configured for synchronizing to a DVB-H signal emitted at a respective frequency, and for scanning frequency values, in order to determine available frequencies.

[0016] The demodulator 16 is configured for demodulating the signal to which the tuner is synchronized, in order to allow the terminal 10 to display a service to the user.

[0017] The synchronizing device 18 comprises a module 20 for determining a first surface of a first coverage zone, in which the tuner is located, and over which a first DVB-H signal is emitted, when the tuner 14 is synchronized with the first DVB-H signal.

[0018] The synchronizing device 18 further comprises a module 22 for determining second surfaces of second coverage zones, over each a respective second DVB-H signal is emitted, at a respective second frequency.

[0019] More precisely, the module 20 and the module 22 are configured for using service information conveyed in the first DVB-H signal. Preferably, the service information comprise SI/PSI tables.

[0020] The synchronizing device 18 further comprises a module 24 for determining, amongst the second coverage zones, a second coverage zone, referred to as the most probable second coverage zone, whose second surface has the greater overlapping with the surface of the first coverage zone.

[0021] The synchronizing device 18 further comprises a module 26 for attempting to synchronize the tuner 12 with the most probable second coverage zone.

[0022] The synchronizing device 18 further comprises a module 28 for obtaining, in case attempting to synchronize with the second signal of the most probable second coverage zone is unsuccessful, the frequency values of the frequencies of all the second coverage zones of the second network.

[0023] More precisely, the frequency values of all the frequencies of the second coverage zones are obtained from service information conveyed in the first DVB-H signal. Preferably, the service information comprise SI/PSI tables.

[0024] The synchronizing device 18 further comprises a module 30 for controlling the tuner 12 for scanning the obtained frequency values, in order to determine available frequencies of the second coverage zones.

[0025] The synchronizing device 18 further comprises a module 32 for synchronizing the tuner 14 with a second signal emitted at one of the available frequencies.

[0026] Referring to figure 2, a method, achieved by the synchronizing device 18, for synchronizing the tuner 14 will now be explained.

[0027] The mobile phone 10 is located in a first DVB-H network, as well as in a second DVB-H network, distinct from the first DVB-H network.

[0028] The first DVB-H network comprises a plurality of first coverage zones. Over each first coverage zone, a respective first DVB-H signal is emitted, at a respective frequency. The mobile phone 10, and thus the tuner 14, is located in one of the first coverage zones, referred to as the current coverage zone. The current coverage zone has a first surface. A first DVB-H signal, referred to as the current DVB-H signal, is emitted over the current coverage zone.

[0029] The tuner 14 is synchronized with the current DVB-H signal, in order to receive at least one service conveyed by the current DVB-H signal. The demodulator 14 demodulates the time slices (also called bursts) dedicated to the at least one service being received.

[0030] The second DVB-H network comprises a plurality of second coverage zones. Over each second coverage zone, a respective second DVB-H signal is emitted, at a respective frequency. Each second coverage zone has a second surface.

[0031] The method first comprises the module 20 determining (step 100) the first surface of the first coverage zone, by using the SI/PSI tables conveyed in the current DVB-H signal. More precisely, the SI/PSI tables store surface information of all the first coverage zones of the first DVB-H network, in the form of the coordinates of two points, defining a rectangular coverage zone.

[0032] The method further comprises the module 22 determining (step 102) the second surfaces of all the second coverage zones of the second DVB-H network. Similarly, the SI/PSI tables conveyed in the current DVB-H signal are used. More precisely, it is common that different networks exchange service information. Therefore, the SI/PSI tables conveyed in the current DVB-H signal of the first network also store surface information of all the second coverage zones of the second DVB-H network, in the form of the coordinates of two points, defining a rectangular coverage zone.

[0033] The method further comprises the module 24 determining (step 104), amongst the second coverage zones, a second coverage zone, whose second surface has the greater overlapping with the surface of the first coverage zone. This is realized by comparing the size and the position of rectangular zones.

[0034] The determined second coverage zone is referred to as the most probable second coverage zone, because it is the second coverage zone in which the mobile phone 10 has the most chance to be located (because of the overlapping). It is therefore worth to try to synchronize the tuner 14 to the second signal emitted in this most probable zone, before scanning the frequency values of the frequencies of all the second coverage zones.

[0035] Consequently, the method further comprises the module 26 attempting (step 106) to synchronize the tuner 14 with second signal of the most probable second coverage zone, in order to receive at least one second service, the at least one second service being different from the at least one first service.

[0036] However, it is not sure that the mobile phone 10 is actually located in the most probable zone.

[0037] Consequently, the method further comprises, in case attempting to synchronize with the most probable second coverage zone is unsuccessful, the module 28 obtaining (step 108) the frequency values of the frequencies of all the second coverage zones, the module 30 controlling (step 110) the tuner 14 for scanning the obtained frequency values, in order to determine available frequencies of the second coverage zones, and the module 32 synchronizing (step 112) the tuner 14 with a second signal emitted at one of the available frequencies.


Claims

1. Method for switching reception from a first service to a second service different from the first service by synchronizing a tuner (14), a first signal being emitted over a first coverage zone having a first surface, the tuner (14) being located in the first coverage zone, the tuner (14) being synchronized with the first signal, in order to receive the first service, the method comprising:

- determining (1 00) the first surface of the first coverage zone,

- determining (102) second surfaces of second coverage zones, over each a respective second signal is emitted, each second signal being emitted at a respective frequency, the method being characterized in that it further comprises:

- determining (104), amongst the second coverage zones, a second coverage zone, referred to as the most probable second coverage zone, whose second surface has the greater overlapping with the surface of the first coverage zone,

- attempting (106) to synchronize the tuner (14) with the second signal emitted over the most probable second coverage zone, in order to receive the second service,

in case attempting (106) to synchronize with the second signal emitted over the most probable second coverage zone is unsuccessful,

- obtaining (108) the frequency values of the frequencies of the second coverage zones,

- controlling (110) the tuner (14) for scanning the obtained frequency values, in order to determine available frequencies of the second coverage zones,

- synchronizing (112) the tuner (14) with a second signal emitted at one of the available frequencies, in order to receive the second service.


 
2. Method according to claim 1, further characterized in that determining (100) the first surface of the first coverage zone, and determining (102) second surfaces of second coverage zones is realized from service information conveyed in the first signal.
 
3. Method according to claim 2, further characterized in that:

- the first signal is a DVB-H signal, and

- the service information comprises SI/PSI tables.


 
4. Method according to any one of claims 1 to 3, further characterized in that the first coverage zone belongs to a first network, while the second coverage zones belongs to a second network, which is distinct from the first network.
 
5. System comprising a tuner (14) and a device (18) for switching reception from a first service to a second service different from the first service by synchronizing the tuner (14), the device comprising:

- a module (20) for determining a first surface of a first coverage zone, in which the tuner (14) is located, and over which a first signal is emitted, the tuner (14) being synchronized with the first signal in order to receive the first service,

- a module (22) for determining second surfaces of second coverage zones, over each a respective second signal is emitted, each second signal being emitted at a respective frequency, characterized in that the device further comprises:

- a module (24) for determining, amongst the second coverage zones, a second coverage zone, referred to as the most probable second coverage zone, whose second surface has the greater overlapping with the surface of the first coverage zone,

- a module (26) for attempting to synchronize the tuner (14) with the second signal of the most probable second coverage zone, in order to receive the second service,

- a module (28) for obtaining, in case attempting to synchronize with the second signal emitted over the most probable second coverage zone is unsuccessful, the frequency values of the frequencies of the second coverage zones,

- a module (30) for controlling the tuner (14) for scanning the obtained frequency values, in order to determine available frequencies of the second coverage zones,

- a module (32) for synchronizing the tuner (14) with a second signal emitted at one of the available frequencies, in order to receive the second service.


 
6. System according to claim 5, further characterized in that the module (20) for determining a first surface and the module (22) for determining second surfaces are configured for using service information conveyed in the first signal.
 
7. System according to claim 6, further characterized in that, the first signal is a DVB-H signal and the service information comprises SI/PSI tables.
 
8. System according to any one of claims 5 to 7, further characterized in that the first coverage zone belongs to a first network, while the second coverage zones belongs to a second network that is distinct from the first network.
 
9. DVB-H receiver (12) comprising a demodulator (16) for demodulating the current signal, and a system according to any one of claims 5 to 8.
 
10. Mobile phone (10) comprising a DVB-H receiver (12) according to claim 9.
 


Ansprüche

1. Verfahren zum Schalten des Empfangs von einem ersten Dienst auf einen zweiten Dienst, der verschieden von dem ersten Dienst ist, indem ein Tuner (14) synchronisiert wird, wobei ein erstes Signal über eine erste Abdeckungszone mit einer ersten Oberfläche ausgesendet wird, wobei der Tuner (14) sich in der ersten Abdeckungszone befindet, wobei der Tuner (14) mit dem ersten Signal synchronisiert wird, um den ersten Dienst zu empfangen, wobei das Verfahren aufweist:

- Bestimmen (100) der ersten Oberfläche der ersten Abdeckungszone,

- Bestimmen (102) zweiter Oberflächen zweiter Abdeckungszonen, über die jeweils ein jeweiliges zweites Signal ausgesendet wird, wobei jedes zweite Signal mit einer jeweiligen Frequenz ausgesendet wird, wobei das Verfahren dadurch gekennzeichnet ist, dass es ferner aufweist:

- Bestimmen (104) einer zweiten Abdeckungszone aus den zweiten Abdeckungszonen, auf die als die wahrscheinlichste zweite Abdeckungszone Bezug genommen wird, deren zweite Oberfläche die größere Überlappung mit der Oberfläche der ersten Abdeckungszone hat,

- Versuchen (106), den Tuner (14) mit dem zweiten Signal zu synchronisieren, das über die wahrscheinlichste zweite Abdeckungszone ausgesendet wird, um den zweiten Dienst zu empfangen,

falls der Versuch (106), mit dem zweiten Signal, das über die wahrscheinlichste zweite Abdeckungszone ausgesendet wird, zu synchronisieren, nicht erfolgreich ist,

- Gewinnen (108) der Frequenzwerte der Frequenzen der zweiten Abdeckungszonen,

- Steuern (110) des Tuners (14), um die gewonnenen Frequenzwerte abzutasten, um verfügbare Frequenzen der zweiten Abdeckungszonen zu bestimmen,

- Synchronisieren (112) des Tuners (14) mit einem zweiten Signal, das mit einer der verfügbaren Frequenzen emittiert wird, um den zweiten Dienst zu empfangen.


 
2. Verfahren nach Anspruch 1, ferner dadurch gekennzeichnet, dass das Bestimmen (100) der ersten Oberfläche der ersten Abdeckungszone und das Bestimmen (102) zweiter Oberflächen der zweiten Abdeckungszonen mit Dienstinformationen realisiert wird, die in dem ersten Signal übermittelt werden.
 
3. Verfahren nach Anspruch 2, ferner dadurch gekennzeichnet, dass:

- das erste Signal ein DVB-H-Signal ist, und

- die Dienstinformationen SI/PSI-Tabellen aufweisen.


 
4. Verfahren nach einem der Ansprüche 1 bis 3, ferner dadurch gekennzeichnet, dass die erste Abdeckungszone zu einem ersten Netzwerk gehört, während die zweiten Abdeckungszonen zu einem zweiten Netzwerk gehören, das verschieden von dem ersten Netzwerk ist.
 
5. System, das einen Tuner (14) und eine Vorrichtung (18) zum Schalten des Empfangs von einem ersten Dienst auf einen zweiten Dienst, der verschieden von dem ersten Dienst ist, aufweist, indem der Tuner (14) synchronisiert wird, wobei die Vorrichtung aufweist:

- ein Modul (20) zum Bestimmen einer ersten Oberfläche einer ersten Abdeckungszone, in welcher der Tuner (14) sich befindet, und über welche ein erstes Signal ausgesendet wird, wobei der Tuner (14) mit dem ersten Signal synchronisiert wird, um den ersten Dienst zu empfangen,

- ein Modul (22) zum Bestimmen zweiter Oberflächen zweiter Abdeckungszonen, über die jeweils ein jeweiliges zweites Signal ausgesendet wird, wobei jedes zweite Signal mit einer jeweiligen Frequenz ausgesendet wird, dadurch gekennzeichnet, dass die Vorrichtung ferner aufweist:

- ein Modul (24) zum Bestimmen einer zweiten Abdeckungszone aus den zweiten Abdeckungszonen, auf die als die wahrscheinlichste zweite Abdeckungszone Bezug genommen wird, deren zweite Oberfläche die größere Überlappung mit der Oberfläche der ersten Abdeckungszone hat,

- ein Modul (26), um zu versuchen, den Tuner (14) mit dem zweiten Signal der wahrscheinlichsten zweiten Abdeckungszone zu synchronisieren, um den zweiten Dienst zu empfangen,

- ein Modul (28), um in dem Fall, dass der Versuch, mit dem zweiten Signal, das über die wahrscheinlichste zweite Abdeckungszone ausgesendet wird, zu synchronisieren, nicht erfolgreich ist, die Frequenzwerte der Frequenzen der zweiten Abdeckungszonen zu gewinnen,

- ein Modul (30) zum Steuern des Tuners (14), um die gewonnenen Frequenzwerte abzutasten, um verfügbare Frequenzen der zweiten Abdeckungszonen zu bestimmen,

- ein Modul (32) zum Synchronisieren des Tuners (14) mit einem zweiten Signal, das bei einer der verfügbaren Frequenzen emittiert wird, um den zweiten Dienst zu empfangen.


 
6. System nach Anspruch 5, ferner dadurch gekennzeichnet, dass das Modul (20) zum Bestimmen einer ersten Oberfläche und das Modul (22) zum Bestimmen zweiten Oberflächen konfiguriert sind, um Dienstinformationen zu nutzen, die in dem ersten Signal übermittelt werden.
 
7. System nach Anspruch 6, ferner dadurch gekennzeichnet, dass das erste Signal ein DVB-H-Signal ist, und die Dienstinformationen SI/PSI-Tabellen aufweisen.
 
8. System nach einem der Ansprüche 5 bis 7, ferner dadurch gekennzeichnet, dass die erste Abdeckungszone zu einem ersten Netzwerk gehört, während die zweiten Abdeckungszonen zu einem zweiten Netzwerk gehören, das verschieden zu dem ersten Netzwerk ist.
 
9. DVB-H-Empfänger (12), der einen Demodulator (16) zum Demodulieren des aktuellen Signals und ein System nach einem der Ansprüche 5 bis 8 aufweist.
 
10. Mobiltelefon (10), das einen DVB-H-Empfänger (12) nach Anspruch 9 aufweist.
 


Revendications

1. Procédé de commutation de réception d'un premier service vers un second service différent du premier service par synchronisation d'un tuner (14), un premier signal étant émis dans une première zone de couverture ayant une première surface, le tuner (14) étant situé dans la première zone de couverture, le tuner (14) étant synchronisé avec le premier signal afin de recevoir le premier service,
le procédé comprenant :

- la détermination (100) de la première surface de la première zone de couverture,

- la détermination (102) de secondes surfaces de secondes zones de couverture, dans chacune desquelles un second signal respectif est émis, chaque second signal étant émis à une fréquence respective,

le procédé étant caractérisé en ce qu'il comprend en outre :

- la détermination (104), parmi les secondes zones de couverture, d'une seconde zone de couverture, désignée en tant que seconde zone de couverture la plus probable, dont une seconde surface a le plus grand chevauchement avec la surface de la première zone de couverture,

- l'essai (106) de synchronisation du tuner (14) avec le second signal émis dans la seconde zone de couverture la plus probable afin de recevoir le second service,

dans le cas où l'essai (106) de synchronisation avec le second signal émis dans la seconde zone de couverture la plus probable ne réussit pas,

- l'obtention (108) des valeurs de fréquence des fréquences des secondes zones de couverture,

- la commande (110) du tuner (14) pour balayer les valeurs de fréquence obtenues afin de déterminer des fréquences disponibles des secondes zones de couverture,

- la synchronisation (112) du tuner (14) avec un second signal émis à une des fréquences disponibles afin de recevoir le second service.


 
2. Procédé selon la revendication 1, caractérisé en outre en ce que la détermination (100) de la première surface de la première zone de couverture et la détermination (102) de secondes surfaces de secondes zones de couverture sont réalisées à partir d'informations de service transportées dans le premier signal.
 
3. Procédé selon la revendication 2, caractérisé en outre en ce que :

- le premier signal est un signal DVB-H, et

- les informations de service comprennent des tables SI/PSI.


 
4. Procédé selon l'une quelconque des revendications 1 à 3, caractérisé en outre en ce que la première zone de couverture appartient à un premier réseau tandis que les secondes zones de couverture appartiennent à un second réseau qui est distinct du premier réseau.
 
5. Système comprenant un tuner (14) et un dispositif (18) pour commuter une réception d'un premier service vers un second service différent du premier service par synchronisation du tuner (14), le dispositif comprenant :

- un module (20) pour déterminer une première surface d'une première zone de couverture, dans laquelle le tuner (14) est situé et dans laquelle un premier signal est émis, le tuner (14) étant synchronisé avec le premier signal afin de recevoir le premier service,

- un module (22) pour déterminer des secondes surfaces de secondes zones de couverture, dans chacune desquelles un second signal respectif est émis, chaque second signal étant à une fréquence respective,

caractérisé en ce que le dispositif comprend en outre :

- un module (24) pour déterminer, parmi les secondes zones de couverture, une seconde zone de couverture, désignée en tant que seconde zone de couverture la plus probable, dont une seconde surface a le plus grand chevauchement avec la surface de la première zone de couverture,

- un module (26) pour essayer de synchronisation du tuner (14) avec le second signal de la seconde zone de couverture la plus probable afin de recevoir le second service,

- un module (28) pour obtenir, dans le cas où l'essai de synchronisation du second signal émis dans la seconde zone de couverture la plus probable ne réussit pas, les valeurs de fréquence pour les fréquences des secondes zones de couverture,

- un module (30) pour commander le tuner (14) pour balayer les valeurs de fréquence obtenues afin de déterminer des fréquences disponibles des secondes zones de couverture,

- un module (32) pour synchroniser le tuner (14) avec un second signal émis à l'une des fréquences disponibles afin de recevoir le second service.


 
6. Système selon la revendication 5, caractérisé en outre en ce que le module (20) pour déterminer une première surface et le module (22) pour déterminer des secondes surfaces sont configurés pour utiliser des informations de service transportées dans le premier signal.
 
7. Système selon la revendication 6, caractérisé en outre en ce que le premier signal est un signal DVB-H et les informations de service comprennent des tables SI/PSI.
 
8. Système selon l'une quelconque des revendications 5 à 7, caractérisé en outre en ce que la première zone de couverture appartient à un premier réseau tandis que les secondes zones de couverture appartiennent à un second réseau qui est distinct du premier réseau.
 
9. Récepteur DVB-H (12) comprenant un démodulateur (16) pour démoduler le signal actuel, et un système selon l'une quelconque des revendications 5 à 8.
 
10. Téléphone mobile (10) comprenant un récepteur DVB-H (12) selon la revendication 9.
 




Drawing









REFERENCES CITED IN THE DESCRIPTION



This list of references cited by the applicant is for the reader's convenience only. It does not form part of the European patent document. Even though great care has been taken in compiling the references, errors or omissions cannot be excluded and the EPO disclaims all liability in this regard.

Patent documents cited in the description