WO2000008783A1 - Device and system for integrating and processing infrared (ir) and radio frequency (rf) signals - Google Patents

Device and system for integrating and processing infrared (ir) and radio frequency (rf) signals Download PDF

Info

Publication number
WO2000008783A1
WO2000008783A1 PCT/US1999/017639 US9917639W WO0008783A1 WO 2000008783 A1 WO2000008783 A1 WO 2000008783A1 US 9917639 W US9917639 W US 9917639W WO 0008783 A1 WO0008783 A1 WO 0008783A1
Authority
WO
WIPO (PCT)
Prior art keywords
signals
radio frequency
infrared
transmitting
appliance
Prior art date
Application number
PCT/US1999/017639
Other languages
French (fr)
Inventor
Michael R. Watson
Original Assignee
Calibre, Inc.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Calibre, Inc. filed Critical Calibre, Inc.
Priority to EP99938980A priority Critical patent/EP1072110A1/en
Publication of WO2000008783A1 publication Critical patent/WO2000008783A1/en

Links

Classifications

    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04BTRANSMISSION
    • H04B10/00Transmission systems employing electromagnetic waves other than radio-waves, e.g. infrared, visible or ultraviolet light, or employing corpuscular radiation, e.g. quantum communication
    • H04B10/11Arrangements specific to free-space transmission, i.e. transmission through air or vacuum
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04BTRANSMISSION
    • H04B1/00Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
    • H04B1/38Transceivers, i.e. devices in which transmitter and receiver form a structural unit and in which at least one part is used for functions of transmitting and receiving
    • H04B1/40Circuits
    • H04B1/403Circuits using the same oscillator for generating both the transmitter frequency and the receiver local oscillator frequency
    • H04B1/406Circuits using the same oscillator for generating both the transmitter frequency and the receiver local oscillator frequency with more than one transmission mode, e.g. analog and digital modes

Definitions

  • a user may use a magnetic or "smart" card to activate a payphone and enable it to receive Ir or RF
  • the preferred system and device should include means for receiving both Ir and RF signals. It is another object that the device include a dual mode signal conditioning means for
  • FIG. 3 is a functional schematic of a preferred embodiment of the Dual
  • Figures 1A and IB are functional schematics of electronic appliances
  • FIG 2 is a functional schematic of a preferred embodiment of the Dual Mode Receive/Infrared Transmit (“DMR-IRX”) Transceiver 34 of the present invention.
  • the DMR-IRX transceiver 34 comprises an IR transmitter 18 (of the conventional design)
  • the DMR-RFX transceiver 40 is a DMR-IRX transceiver 34 that has one or more RF transmitters 28 for transmitting RF signals 30
  • the DMR-IRX appliance 42 is capable of transmitting
  • the DMR-RFX appliance 44 is an electronic device of the type described above that includes a DMR-

Landscapes

  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Optical Communication System (AREA)

Abstract

A device and system for integrating and processing Infrared (IR) and Radio Frequency (RF) signals is disclosed. The preferred system and device includes means for receiving both IR and RF signals. The device includes a dual mode signal conditioning means for processing received IR and RF signals. The device further is available in a variety of embodiments, including devices capable of transmitting IR signals only, devices capable of transmitting RF signals only, and 'dual mode' devices capable of transmitting both IR and RF signals. The preferred device also includes transmit switch means for switching a transmit module between IR transmission and RF transmission modes. The preferred device further permits simultaneous transmission of IR and RF signals.

Description

DEVICE AND SYSTEM FOR INTEGRATING AND PROCESSING INFRARED (IR) AND RADIO FREQUENCY (RF) SIGNALS
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates generally to infrared (IR) and radio frequency (RF)
communications systems and, more specifically, to a Device and System for Integrating
and Processing Infrared (IR) and Radio Frequency (RF) Signals.
2. Description of Related Art
As technology becomes continually more accessible to the "common man," the ability to use, store, transfer and otherwise manipulate information has become the focus of most businesses as well as for the individual consumer. Access to the
information resources is commonly by some sort of network system, including World
Wide Web, "Intranets", local area networks, wide area networks, as well as corporate databases.
While the conventional method for connecting to one of these information
networks has been via cable and wire, as the reliance upon connectivity to information has
deepened, the desire to gain such access from mobile or portable devices has
strengthened. These portable devices, such as Personal Digital Assistants, handheld computers, and even cellular telephones are now being connected to each other and to
networks via Infrared Data Communications or via Radio Frequency Data Communications, depending upon the particular appliance. For example, a user may use a magnetic or "smart" card to activate a payphone and enable it to receive Ir or RF
transmissions from their digital camera - the stored data could then be transmitted to a
photo processing service for production. These wireless technologies have become so
promising that it is virtually impossible to purchase a notebook computer today that does
not include some wireless communications assembly resident within it.
The key problem with these wireless communications systems is one of
cross-type incompatibility - once a device is built and configured to communicate via IR signals, it cannot communicate with RF signaling appliances, and vice versa. Each
transmission type has its unique strengths and weaknesses, as well as proponents and detractors. This schism between the transmission types has and continues to create unrest and uncertainty in the electronic appliance market - no clear leader has evolved, but the
constant battling serves to weaken the development of both technologies significantly. What would be extremely helpful would be a device and system that is selectively capable of enabling communications with both IR-based and RF-based
appliances, without significantly increasing the cost of the appliances. A cross-type
appliance such as this would be able to use both communications types to their full extent,
in applications where each is best suited.
SUMMARY OF THE INVENTION In light of the aforementioned problems associated with the prior devices and systems, it is an object of the present invention to provide a Device and System for Integrating and Processing Infrared (IR) and Radio Frequency (RF) Signals. The
preferred system and device should include means for receiving both Ir and RF signals. It is another object that the device include a dual mode signal conditioning means for
processing received Ir and RF signals. It is a further object that the device be available in
a variety of embodiments, including devices capable of transmitting Ir signals only,
devices capable of transmitting RF signals only, and "dual mode" devices capable of transmitting both Ir and RF signals. The preferred device should include transmit switch means for switching a transmit module between Ir transmission and RF transmission
modes. It is yet another object that the preferred device permit simultaneous transmission
of Ir and RF signals.
BRIEF DESCRIPTION OF THE DRAWINGS
The objects and features of the present invention, which are believed to be novel, are set forth with particularity in the appended claims. The present invention, both
as to its organization and manner of operation, together with further objects and
advantages, may best be understood by reference to the following description, taken in connection with the accompanying drawings, of which:
Figures 1A and IB are functional schematics of electronic appliances
incorporating prior IR and RF communication systems;
Figure 2 is a functional schematic of a preferred embodiment of the Dual
Mode Receive/Infrared Transmit Transceiver of the present invention;
Figure 3 is a functional schematic of a preferred embodiment of the Dual
Mode Receive/Radio Frequency Transmit Transceiver of the present invention;
Figure 4 is a functional schematic depicting the ability of an Infrared- transmitting appliance to communicate with a Radio frequency-transmitting appliance
where both are equipped with the Dual Mode Receiver of the present invention; and
Figure 5 is a functional schematic of a preferred embodiment of an
appliance equipped with the Dual Mode Receive/Dual Mode Transmit Transceiver of the
present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The following description is provided to enable any person skilled in the
art to make and use the invention and sets forth the best modes contemplated by the inventor of carrying out his invention. Various modifications, however, will remain readily apparent to those skilled in the art, since the generic principles of the present invention have been defined herein specifically to provide a Device and System for
Integrating and Processing Infrared (IR) and Radio Frequency (RF) Signals.
The present invention can best be understood by initial consideration of
Figures 1A and IB. Figures 1A and IB are functional schematics of electronic appliances
10 and 12 incorporating prior IR and RF communication systems. In its typical form, the
appliance with IR communications 10 comprises a communications controller 14 that is in communication with an IR transceiver 16. It should be appreciated that the
communications controller 14 may be a stand-alone circuit, or it may be integrated into
the Central Processing Unit of the appliance 10, depending upon the configuration of the particular appliance 10.
The typical IR transceiver 16 comprises an IR transmitter 18 for
transmitting IR signals 20 to another appliance or device, and an IR receiver 22 for
receiving IR signals 20 emanating from another appliance or device. The signals entering
the IR transmitter 18 and leaving the IR receiver 22 are conditioned and processed for or
from the communications controller 14 by a signal processor 24. Similarly, the typical RF transceiver 26 comprises an RR transmitter 28 for transmitting RF signals 30 to another appliance or device, and an RF receiver 32 for
receiving RF signals 30 emanating from another appliance or device. The signals entering
the RF transmitter 28 and leaving the RF receiver 32 are conditioned and processed for or
from the communications controller 14 by a signal processor 24.
It should pointed out that the conventional optical photodiodes used for IR
receivers 22 utilize the same core high frequency bipolar silicon (HF-Si) or silicon- germanium (SiGe) technologies that are utilized in the manufacture of RF receivers 32.
Now turning to Figure 2, we can begin to explain the value of the present invention. Figure 2 is a functional schematic of a preferred embodiment of the Dual Mode Receive/Infrared Transmit ("DMR-IRX") Transceiver 34 of the present invention. The DMR-IRX transceiver 34 comprises an IR transmitter 18 (of the conventional design)
for transmitting IR signals 20 to external devices. The unique aspect of this apparatus is
inclusion of the Dual Mode Receiver ("DMR") 36, which is a unit configured to detect
and receive both incident IR signals 20 and incident RF signals 30. Since the
manufacturing technology for the conventional single-mode receivers is similar, the DMR 36 may be crafted from a single semiconductor substrate using HF-Si or SiGe technology.
As such, the DMR 36 circuit could be designed to contain a mixed signal analog/digital
receiver-demodulator capable of receiving and conditioning a received RF signal 30. At the same time, either substrate technology can function as an IR photodiode receiver (see above). Consequently, the DMR 36 can process the detected RF or IR signals 30 and 20
in a common receive circuit, or it can send the raw signal to a separate Dual Mode Signal
Processor/Conditioner ("DMSP") 38. The DMSP 38 could be further configured to provide separate outputs for the received IR and RF signals, respectively, or there could be one single output (as
shown in this depiction). In any case, it should be appreciated that the DMR 34, as a
single circuit replacement for the conventional single-mode IR and RF signal receivers, provides increased appliance functionality, reduced power consumption, optimization of
circuit real estate, and an overall lower cost. Finally, it must be understood that the single
IR transmitter 18 and single DMR 36 presented here is only one example; it might be
desirable to include a plurality of transmitters 18 and/or DMRs 36 to provide increased
functionality.
Figure 3 depicts a device that is closely related to the DMR-IRX transceiver 34 of Figure 2. Figure 3 is a functional schematic of a preferred embodiment of the Dual Mode Receive/Radio Frequency Transmit ("DMR-RFX") Transceiver 40 of
the present invention. Essentially, the DMR-RFX transceiver 40 is a DMR-IRX transceiver 34 that has one or more RF transmitters 28 for transmitting RF signals 30
instead of the IR transmitter(s) of the DMR-IRX transceiver 34. Figure 4 describes the
incredible versatility provided by the DMR-RFX and DMR-IRX transceivers 40 and 34.
Figure 4 is a functional schematic depicting the ability of an Infrared-
transmitting appliance to communicate with a Radio frequency-transmitting appliance
where both are equipped with the DMR 36 of the present invention. The DMR-IRX appliance 42 is a portable computer, telephone, personal digital assistant or other
electronic device that includes a DMR-IRX transceiver 34 as described above in
connection with Figure 2. As such, the DMR-IRX appliance 42 is capable of transmitting
IR signals 20, while able to receive both IR signals 20 and RF signals 30. The DMR-RFX appliance 44 is an electronic device of the type described above that includes a DMR-
RFX transceiver 40 as described above in connection with Figure 3. The DMR-RFX appliance 44, therefore, can transmit RF signals 30 and receive both IR signals 20 and RF
signals 30. As can be seen, the DMR-IRX appliance 42, by transmitting IR signals 20 is fully capable of communicating with the DMR-RFX appliance 44, which is limited to transmitting only RF signals 30. This capability provides astounding functionality that
was previously unavailable. Prior IR signal-transmitting devices could not communicate
at all with RF signal-transmitting devices; the manufacturer and user were forced to
choose (possibly at great limitation) between one signal technology and the other. Now,
with the present invention, a simple upgrade to the receiver capability (i.e. exchange with a DMR 36) permits the single-mode transmitter device to communicate with a similarly-
configured device transmitting the other type of signal!
Figure 5 provides yet another embodiment of the present invention.
Figure 5 is a functional schematic of a preferred embodiment of an appliance 46 equipped with the Dual Mode Receive/Dual Mode Transmit ("DMR-DMX") Transceiver 48 of the
present invention. As can be seen, the DMR-DMX appliance 46 includes a DMR-DMX
transceiver 48; this unique transceiver 48 comprises that DMR 36 for receiving both IR
and RF signals 20 and 30, as discussed previously. Furthermore, the DMR-DMX
transceiver 48 includes a Dual Mode Transmit Module 50. The Dual Mode Transmit
Module 50 is, essentially, at least one each IR transmitter 18 and RF transmitter 28,
respectively. The two transmitters 18 and 28 are preferably coupled to an IR/RF transmit
switch 52. The IR/RF transmit switch 52 allows the outgoing signal coming from the Dual Mode Signal Conditioner 54 to be routed to either the IR transmitter 18 or the RF
transmitter 28, or to both simultaneously. In operation, therefore, the DMR-DMX
appliance 46 can selectively communicate with IR-based, RF-based or dual-mode external
appliances. This flexibility permits the appliance 46 to be adaptable to any and all IR and RF networks and systems, and in particular, it permits the appliance to capitalize on the strengths of each signal transmission technology, as appropriate.
Those skilled in the art will appreciate that various adaptations and
modifications of the just-described preferred embodiment can be configured without departing from the scope and spirit of the invention. Therefore, it is to be understood that, within the scope of the appended claims, the invention may be practiced other than as
specifically described herein.

Claims

CLAIMSWhat Is Claimed Is:
1. A signal transceiver device, comprising a dual mode receiver, said receiver comprising:
infrared receiving means for receiving infrared signals incident thereon; and
radio frequency receiving means for receiving radio frequency signals incident thereon.
2. The device of Claim 1 , further comprising infrared transmitting means for transmitting infrared signals.
3. The device of Claim 1 , further comprising radio frequency transmitting means for transmitting radio frequency signals.
4. The device of Claim 1 , further comprising a dual mode transmitting module for transmitting infrared and radio frequency signals.
5. The device of Claim 4, wherein said dual mode transmitting module further comprises transmit switch means for switching said module between transmitting said signals as infrared signals and transmitting said signals as radio frequency signals.
6. The device of Claim 5, wherein said transmit switch means permits simultaneous transmission of infrared and radio frequency signals.
7. The device of Claim 2, further comprising dual mode signal conditioning means for processing said received infrared and radio frequency signals.
8. The device of Claim 3, further comprising dual mode signal conditioning means for processing said received infrared and radio frequency signals.
9. The device of Claim 4, further comprising dual mode signal conditioning means for processing said received infrared and radio frequency signals.
10. The device of Claim 5, further comprising dual mode signal conditioning means for processing said received infrared and radio frequency signals.
11. The device of Claim 1, wherein said infrared receiving means and said radio frequency receiving means are constructed on a single semiconductor substrate.
12. The device of Claim 11 , wherein said infrared receiving means and said radio frequency receiving means comprise a single electronic circuit.
13. An improved communication system, comprising:
a first appliance comprising infrared transmitting means for transmitting infrared signals and dual mode receiving means for receiving infrared and radio frequency signals; and
whereby said first appliance may communicate with a second appliance, said second appliance configured to transmit either infrared signals or radio frequency signals, or both said infrared and radio frequency signals.
14. The system of Claim 13, wherein said second appliance comprises infrared transmitting means for transmitting infrared signals and receiving means for receiving infrared signals.
15. The system of Claim 14, wherein said second appliance receiving means further comprises means for receiving radio frequency signals.
16. The system of Claim 13, wherein said second appliance comprises radio frequency transmitting means for transmitting radio frequency signals and receiving means for receiving infrared signals.
17. The system of Claim 16, wherein said second appliance receiving means further comprises means for receiving radio frequency signals.
18. The system of Claim 13, wherein: said first appliance further comprises radio frequency transmitting means for transmitting radio frequency signals; and
said second appliance further comprises means for transmitting infrared signals.
19. The system of Claim 18, further comprising transmit switch means for altematingly switching signal output between said infrared transmitting means and said radio frequency transmitting means.
PCT/US1999/017639 1998-08-03 1999-08-03 Device and system for integrating and processing infrared (ir) and radio frequency (rf) signals WO2000008783A1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
EP99938980A EP1072110A1 (en) 1998-08-03 1999-08-03 Device and system for integrating and processing infrared (ir) and radio frequency (rf) signals

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US12821998A 1998-08-03 1998-08-03
US09/128,219 1998-08-03

Publications (1)

Publication Number Publication Date
WO2000008783A1 true WO2000008783A1 (en) 2000-02-17

Family

ID=22434237

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/US1999/017639 WO2000008783A1 (en) 1998-08-03 1999-08-03 Device and system for integrating and processing infrared (ir) and radio frequency (rf) signals

Country Status (2)

Country Link
EP (1) EP1072110A1 (en)
WO (1) WO2000008783A1 (en)

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2001052450A2 (en) * 2000-01-13 2001-07-19 Lightpointe Communications, Inc. Hybrid wireless optical and radio frequency communication link
WO2002019573A2 (en) * 2000-08-31 2002-03-07 Aerocomm, Inc. System and method for transmitting information modulated radio frequency signals using infrared transmission
WO2002071657A2 (en) * 2001-03-05 2002-09-12 Hrl Laboratories, Llc Hybrid rf and optical wireless communication link and network structure incorporating it therein
EP1308052A1 (en) * 2000-06-15 2003-05-07 Motorola, Inc. Cellular telephone with simultaneous radio and cellular communication
US6868237B2 (en) 1998-04-24 2005-03-15 Lightpointe Communications, Inc. Terrestrial optical communication network of integrated fiber and free-space links which requires no electro-optical conversion between links
US7324755B2 (en) 2002-07-02 2008-01-29 Hrl Laboratories, Llc Optical code-division multiple access transmission system and method
US7409159B2 (en) 2001-06-29 2008-08-05 Hrl Laboratories, Llc Wireless wavelength division multiplexed system

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4904993A (en) * 1986-05-16 1990-02-27 Alps Electric Co., Ltd. Remote control apparatus with selectable RF and optical signal transmission
DE4433896C1 (en) * 1994-09-22 1995-11-09 Siemens Ag Reducing radio transmissions in pico-cellular wireless communications
US5585953A (en) * 1993-08-13 1996-12-17 Gec Plessey Semiconductors, Inc. IR/RF radio transceiver and method

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4904993A (en) * 1986-05-16 1990-02-27 Alps Electric Co., Ltd. Remote control apparatus with selectable RF and optical signal transmission
US5585953A (en) * 1993-08-13 1996-12-17 Gec Plessey Semiconductors, Inc. IR/RF radio transceiver and method
DE4433896C1 (en) * 1994-09-22 1995-11-09 Siemens Ag Reducing radio transmissions in pico-cellular wireless communications

Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6868237B2 (en) 1998-04-24 2005-03-15 Lightpointe Communications, Inc. Terrestrial optical communication network of integrated fiber and free-space links which requires no electro-optical conversion between links
WO2001052450A2 (en) * 2000-01-13 2001-07-19 Lightpointe Communications, Inc. Hybrid wireless optical and radio frequency communication link
WO2001052450A3 (en) * 2000-01-13 2002-04-18 Lightpointe Communications Inc Hybrid wireless optical and radio frequency communication link
AU2001252868B2 (en) * 2000-01-13 2005-06-02 Lightpointe Communications, Inc. Hybrid wireless optical and radio frequency communication link
EP1308052A1 (en) * 2000-06-15 2003-05-07 Motorola, Inc. Cellular telephone with simultaneous radio and cellular communication
EP1308052A4 (en) * 2000-06-15 2009-06-10 Motorola Inc Cellular telephone with simultaneous radio and cellular communication
WO2002019573A2 (en) * 2000-08-31 2002-03-07 Aerocomm, Inc. System and method for transmitting information modulated radio frequency signals using infrared transmission
WO2002019573A3 (en) * 2000-08-31 2003-07-17 Aerocomm Inc System and method for transmitting information modulated radio frequency signals using infrared transmission
WO2002071657A2 (en) * 2001-03-05 2002-09-12 Hrl Laboratories, Llc Hybrid rf and optical wireless communication link and network structure incorporating it therein
WO2002071657A3 (en) * 2001-03-05 2003-11-13 Hrl Lab Llc Hybrid rf and optical wireless communication link and network structure incorporating it therein
US7409159B2 (en) 2001-06-29 2008-08-05 Hrl Laboratories, Llc Wireless wavelength division multiplexed system
US7324755B2 (en) 2002-07-02 2008-01-29 Hrl Laboratories, Llc Optical code-division multiple access transmission system and method

Also Published As

Publication number Publication date
EP1072110A1 (en) 2001-01-31

Similar Documents

Publication Publication Date Title
US8355672B2 (en) Method for identification using bluetooth wireless key
EP0741463B1 (en) Half duplex RF transceiver having low transmit path signal loss
JPH07303283A (en) Assembly of radio trans mission system in radioc communication system
KR890702351A (en) Radio array for cellular communication system and its communication method
WO2000044091A3 (en) Antenna system for radio frequency identification
KR20020026381A (en) Radio communication system, radio communication apparatus, and radio communicating method
US20100067585A1 (en) A wireless communication apparatus and the configuration method thereof
US20080089690A1 (en) Isolating radio frequency components of a wireless device
US5933122A (en) Antenna switch for wireless antenna diversity telecommunications devices with two antennas
EP1072110A1 (en) Device and system for integrating and processing infrared (ir) and radio frequency (rf) signals
US20030069996A1 (en) Infrared to radio frequency adapter and method for using the same
CN207339827U (en) Radio receiver with gain selection function
CN220210468U (en) Transparent transmission device for mobile communication
US20030200434A1 (en) Secure identification method between two radiofredquency network appliances
CN107657195A (en) A kind of three-in-one control system based on NFC, RFID and bluetooth
AU7203598A (en) Method and corresponding devices for processing data from external devices
US7162270B2 (en) Dual communication mode wireless network transmission device
CN208227019U (en) A kind of mobile phone with digital cluster communication function
KR100593608B1 (en) Connection method between wireless handset and telephone body in wireless switching system
US6549760B1 (en) Communications device
KR100606717B1 (en) A Dual UART circuit for a mobile telecommunication device
CN217307674U (en) Wireless transmission device of high-speed serial link and LED display screen
WO2024055723A1 (en) Terminal device
US20040235515A1 (en) Dual frequency wireless network access device
Tasci et al. PSoC based embedded Rf link design

Legal Events

Date Code Title Description
AL Designated countries for regional patents

Kind code of ref document: A1

Designated state(s): AT BE CH CY DE DK ES FI FR GB GR IE IT LU MC NL PT SE

121 Ep: the epo has been informed by wipo that ep was designated in this application
WWE Wipo information: entry into national phase

Ref document number: 1999938980

Country of ref document: EP

WWP Wipo information: published in national office

Ref document number: 1999938980

Country of ref document: EP

WWW Wipo information: withdrawn in national office

Ref document number: 1999938980

Country of ref document: EP