KR100796199B1 - Optical wireless connecting terminal comprising an extended infrared source - Google Patents

Abstract

Optical wireless access terminal with extended infrared power supply

According to an aspect of the present invention, there is provided a communication apparatus comprising a transmitter and a transmitter including a transmitter and receiver configured to exchange information with a remote terminal having a transmitter and receiver, wherein the transmitter and receiver include a transmitter including an extended infrared light source. It relates to a base for wireless connection.

Description

Optical wireless connecting terminal comprising an extended infrared source

The present invention relates to a wireless connection to communication networks.

More specifically, the present invention relates to a high bit rate wireless connection between a user device (user terminal) and a fixed base connected to a long distance telephone or data communication network.

During roaming, more and more users of mobile terminals (mobile phones, portable computers, PDAs, etc.) need to connect once or regularly to fixed or onboard networks (and then to users). By "locally fixed"). To facilitate this roaming connection, operators must extend their networks, especially to certain public spaces (shops, train stations, airports, shopping malls, parking lots, transportation systems, cafes, restaurants, etc.). .

Access bases (also known as access points) are therefore installed in certain areas. These bases are connected to a communication network, for example the Internet, and also allow mobile terminal users moving within these areas to be connected to the network.

In parallel, some professional or non-professional users who are already connected to a fixed network but do not have a sufficiently high bit rate connection to comfortably exchange large amounts of information (eg, transfer or download large files) are sometimes It requires the benefit of a connection with bit rate. Such users will find it convenient to use the above access bases.

Currently, there are several forms of contactless (or wireless) connection technologies that can be used with these access bases.

The first type of technology, based on the exchange of information in the form of radio waves between the mobile terminal and the access base, has a wireless transmit / receive means, for example, a Wi-Fi with access bases known as "hot spots." Wi-Fi) technology.

However, this technique causes problems such as frequency congestion and interference with electronic equipment located near the base. These problems may be a serious problem in any particular context, for example if the base is in an aircraft (interference with equipment in an aircraft), in a hospital (interference with medical equipment), or in any particular industrial environment. Can be.

The second type of technology conceivable is based on the exchange of information in the form of non-guided infrared optical radiation. Currently, the main applications of this technology are mainly related to high directional point-to-point communication in the form of Free Space Optics (FSO), which is intended to connect two spaced apart points hundreds to thousands of meters apart.

The technique relies on transmission with a high directional beam. The reason is that even a small beam divergence can significantly limit the transmission range and may also be unsuitable for conceivable applications. This relates to hot spot access bases, where there is another compromise that can be achieved between cover angle and range.

This infrared technology is also used in personal networks to interconnect different devices with localized infrared transmission, especially in homes or business locations ("indoor" communications).

With such a technique, high bit rate transmissions require an increase in radiated optical power, which may violate the tolerances imposed by the regulations.

1 shows a general principle of the operation of an optical matrix according to the invention;

2 is a diagram showing an example of applying a base according to the present invention to a parking lot;

3 is a diagram illustrating various components constituting an extended infrared light source;

4 is a diagram showing an example of applying a base according to the present invention to a transportation system;

5 shows an example of a base according to the invention installed on a train station platform; Also

6 shows an example of a known application according to the invention usable by pedestrians.

It is an object of the present invention to provide a wireless access means which enables high bit rate communication.

To this end, the present invention provides a base comprising a transmitting and receiving means adapted to exchange information with a remote terminal equipped with a transmitting and receiving means, wherein the known transmitting and receiving means comprises a transmitter including an extended infrared light source. It provides a base for wirelessly connecting a terminal to a communication network.

The concept of an extended infrared light source is defined by the European standard EN-60825-1 "Safety part 1: Classification of equipment, requirements and user guide for laser products". Extended infrared light source means a light source observed by an observer at a distance of 100 mm or more at an angle greater than the angle α _min defined by the above standard.

Infrared can be used to provide fast bit rate contactless connections. The solution proposed by the present invention increases the transmission bit rate by increasing the frequency of the carrier compared to the fixed radio bases currently used. By using wireless technology, the transmission frequency is predetermined and may not be increased.

Even with an extended power source, despite the overall increase in output light output compared to point sources, they remain within the limits of the regulations in terms of visual safety.

The visual safety standard is defined as a function of the size of the power supply and also depends on the wavelength: the higher the power supply, the greater the maximum allowable output power. Thus, it is possible to multiply the output power by an index 1.5 relative to the point light source at a wavelength of 1550 nm. At a wavelength of 810 nm, the index is 300.

Thus, the present invention can make a good compromise between the dimensions of the area covered by the matrix and the transmission bit rate.

The optical known solution proposed by the present invention is transparent to the exchange protocol used. This is because the present invention is located at the physical layer level used to establish the physical connection between communication electronic data processing devices, that is, the first layer of the Open System Interconnection (OSI) reference model. The layer consists of several protocols commonly used to exchange data, e.g., Wi-Fi (i.e. 802.11 a, b, g or n), Ethernet, Giga Ethernet, ATM, SDH, PDH, xSDL, Compatible with either IPv4 or IPv6.

The known transmitter is preferably configured to transmit information to the remote terminal at a high bit rate.

In the context of the present invention, the expression "high bit rate" means a bit rate of more than 10 megabits per second (Mbps) while exceeding 1 gigabit per second (Gbps).

Other features, objects, and advantages of the invention will become apparent upon reading the following detailed description with reference to the accompanying drawings, which are set forth as non-limiting examples.

In FIG. 1, the optical base 10 includes transmitting and receiving means adapted to establish an optical connection with the transmitting and receiving means of the mobile terminal 20 located within the communicable area 100. This base 10 is connected to the communication network 30.

The transmission and reception means of the base 10 includes a transmitter 12 and a receiver 14. The transmitter 12 includes an extended infrared light source.

In the arrival region 100 of the infrared light source, the noise to signal ratio is suitable for conceivable transmission.

Information 1 is transmitted from the base 10 to the terminal 20 via an infrared link with direct, non-direct or hybrid line of sight.

Information 2 is transmitted from the base 10 to the terminal 20 via an infrared link with direct, non-direct or hybrid line of sight as necessary. In the case of a direct or hybrid link, the base 10 and the terminal 20 are means for monitoring the position of the light source and the receiver to achieve optimal alignment of the light source and the transmission and reception means of the terminal 20. It may include.

The receiver 14 of the base 10 is, for example, an omni-directional receiver comprising an omni-directional concentrator. This omnidirectional concentrator can take the form of a hemispherical lens with a hemispherical optical filter or a hemispherical lens with an antireflective surface treatment and a planar optical filter disposed in front of the receiver. The omnidirectional optical receiver 14 has a gain of at least 3 decibels (dB) and a theoretical aperture angle of about 180 degrees.

2, the optical base 10 of the invention is installed in a parking lot. The base 10 includes an extended infrared light source adapted to transmit optical signals and a receiver of a type suitable for conceivable links. The base 10 performs transmission within a defined reach area 100 where a minimum signal to noise ratio is suitable for the application and the considered error rate is achieved.

As illustrated in FIG. 2, the base 10 may be any one of two areas A and B in which the arrival area 100 constituting the communication area is horizontal (configuration A) or vertical (configuration B). In both cases, the communication space surrounds the parking space (3 m x 5 m squares) and also covers most modern vehicles (H _min = 1.5 m, H _max + 3 m, d _ec = 5 m). The user terminal is installed outside or inside the vehicle behind a glass covered surface (eg, windshield).

Table 1 presents the main communication parameters between the optical base and the user terminal as examples in communication space using contactless (wireless) infrared visible non-direct link (WIr LOS-ND link).

The table lists the following variables.

"Bit rate" refers to the communication bit rate between the transmitter and the receiver required by the particular application contemplated;

"Infrared window" refers to the infrared range of an optical carrier expressed in nanometers;

"Average transmit power" refers to the minimum power required to achieve the minimum signal-to-noise ratio in the communication space necessary to achieve the required bit error rate (BER) for a particular application;

“R (Ψ)” refers to a three-dimensional radiation model (eg Lambert model or specific model) of the light source;

"FOV" (field of view) indicates the half-opening angle of the transmitter or receiver;

The receiver marked "No EQ" is a receiver without equalization during the reception process;

"Effective area" means the effective area of said receiver equipped with a filter, a hemispherical concentrator and a PIN diode photodetector;

"Photodetector" (PIN) refers to a PIN diode photodetector;

"Region" refers to the region of the photodetector in cm ² ;

“Sensitivity” refers to the photodetection efficiency of a photodetector expressed in amperes per watt;

"Receiver sensitivity for at least S / N" refers to the minimum optical power encountered at the receiver required to achieve the signal-to-electrical noise ratio required by the particular application;

"Optical filter" (hemi-spherical) refers to a bypass filter deposited or attached to a hemispherical lens;

"Concentrator" (hemisphere) refers to a hemispherical lens with an omnidirectional optical gain of about n ² (n is the refractive index of the lens), equivalent to an optical gain of at least 3 dB relative to a typical refractive index;

"Parking lot EC" or "train EC" refers to a communication area EC in a parking lot or train having dimensions H _min x H _max x d _ec ;

"Wireless infrared link" refers to a line of sight non-direct (LOS-ND) type wireless infrared link;

The " modulation type " refers to the modulation type of the online digital data, which is an On Off Keying / Non Return to Zero (OOK / NRZ) type;

"Channel type" refers to the digital optical channel used, which is an Intensity Modulation / Direct Detection (IM / DD) type; Also

"Free space attenuation" refers to the geometric attenuation experienced by an optical beam between the transmitter and the receiver.

As can be seen in Table 1, the intensity modulation / direct sensing infrared channel is within a window of 810 nm and also uses on-off keying / non-zero return modulation. Available bit rates are 10, 100 and 155 Mbps, which are widely used in existing applications. This table shows that the transmit / receive components used in conceivable bases and mobile terminals can be used with existing technologies.

3 is an illustration of an extended infrared light source of visual safety class I, which may be used in particular in the application shown in FIG. 1.

The extended infrared power source comprises laser transmission means in the form of standard laser diodes 32, 34 and 36, and transmission diffusion means 40 for diffusing the emitted light emitted by the diodes 32, 34 and 36. do. The transmission spreading means 40 consists of a holographic diffuser representing a simple and limited solution for the production of an extended power supply, for example with specific radiating characteristics.

One embodiment of the power source may include a laser emitting means and reflecting means for diffusing the emitted light emitted by the laser emitting means.

Compared to point sources, the use of extended light sources increases the maximum average power that can be emitted within the limits imposed by safety standards. The extended light source can cover a larger communication space 100 and can also achieve a maximum signal-to-noise ratio for communication that can be considered.

In this example, the extended light source is observed by the observer at an angle exceeding 100 milliradians, which corresponds to a minimum diameter of 10 mm with an area of π / 4 cm ² for an observer at a distance of 100 mm.

The maximum allowed average power of Class I for 810 mm pulse extended infrared light sources used at high bit rates with a viewing angle of 60 ° far exceeds the maximum values shown in Table 1. Thus, there may be an increase in the power increase of the extension power source that may be used to expand the communication space, relax the limitation on the performance of the power supply component, or increase the bit rate of the power supply.

Signal-to-noise ratios suitable for the application under consideration are achieved through the communication space indicated in FIG. The communication space is generally in the form of a cylinder of diameter d _ec defined by an upper plane separated by a distance H _min from the power source and a lower plane separated by a distance H _max from the power source. The dimension H _min x H _max x d _ec of the communication space is specified for each application example in Tables 1 and 2.

The known receiver includes a filter, a hemispherical concentrator, and a PIN diode photodetector with a large sensing area (1 cm 2) and medium sensitivity (0.53 amp A / W). This type of receiver can provide a 70 degree viewing angle with a maximum gain of 3.5 dB. The required sensitivity of the receiver is calculated for high levels of background noise (5.8 μW / nm / cm ₂ ), and also at bit rates ranging from -40.5 dB.m (10 Mbps) to -34.5 dB.m (155 Mbps). Change as a function; Achieving it does not represent a particular problem.

4 shows an optical base 10 installed on a passenger seat in a transportation system such as a train, aircraft, ship, or the like. The base is connected to a local area network mounted in the transportation system. The base is housed within the top of the ceiling or seatback facing the user's seat. For this type of application, the dimensions of the communication space covered by the matrix 10 are approximately H _min = 0.5 m, H _max = 1.5 m and d _ec = 1.5 m.

Table 2 provides the main parameters of the communication applied between the optical base and the user terminal in a communication space using a wireless infrared line of sight non-direct (WIr LOS-ND) link. The variables in this table are the same as the variables in Table 1.

5 shows an optical base 10 installed on a train station platform. This horizontal base 10 allows information to be transferred between the fixed network and the local area network mounted on the train when the train is on the platform.

The possibility of the terminal moving at a high speed and performing communication at a very high bit rate is limited, and it may be very advantageous to transfer data in both directions between the transport system and the outside world during stop. The exchange between the storage means and the base is performed at a very fast bit rate so that there is no contact or connection to increase the capacity of the relevant information and also to speed up the procedure.

In the case of stationary trains, the dimensions of the horizontal or vertical communication space are approximately H _min = 1.5 m, H _max = 3 m and d _ec = 3 m. Using an exchange bit rate of 155 Mbps, it is possible to transfer data of 30 Gbits in three minutes of stopping.

This application can be generalized to other transportation systems, for example where the exchange is carried out in a parking lot or an airport. The data exchanged may be linked to the operation of the transportation system (data exchanged by the operator of the transportation system) or may also include information transmitted from or to the passenger in connection with a high quality communication service.

6 shows an optical base 10 installed at a public or private place prepared for pedestrians. This application allows pedestrians entering the site to connect their terminals 20 to the network. This application allows the known variables to have different values compared to the other applications described above. For example, the dimensions H _min = 1.5 m, H _max = 3 m and d _ec = 5 m may be suitable.

Communication space-parking Horizontal (configuration A)   Vertical (configuration B) Bit rate 10 Mbps 100 Mbps 155 Mbps 10 Mbps 100 Mbps 155 Mbps Infrared window 810 nm 810 nm 810 nm 810 nm 810 nm 810 nm Transmission power +11 dBm +17 dBm +18 dBm +16 dBm +21 dBm +22 dBm Power supply type R (ψ) FOV Extended 60 ° Extended 60 ° Extended 60 ° Extended 60 ° Extended 60 ° Extended 60 °

Receiver Effective Area FOV No EQ1.5 cm ² 60 ° No EQ1.5 cm ² 60 ° No EQ1.5 cm ² 60 ° No EQ1.5 cm ² 60 ° No EQ1.5 cm ² 60 ° No EQ1.5 cm ² 60 ° Photodetector Area Sensitivity PIN1 cm ² 0.53 A / W PIN1 cm ² 0.53 A / W PIN1 cm ² 0.53 A / W PIN1 cm ² 0.53 A / W PIN1 cm ² 0.53 A / W PIN1 cm ² 0.53 A / W Receiver Sensitivity to 13.5 dB Minimum S / N -40.5 dBm -35.5 dBm -34.5 dBm -40.5 dBm -35.5 dBm -34.5 dBm Optical Filter Bandwidth Attenuation Hemisphere 20 nm-1.5 dB Hemisphere 20 nm-1.5 dB Hemisphere 20 nm-1.5 dB Hemisphere 20 nm-1.5 dB Hemisphere 20 nm-1.5 dB Hemisphere 20 nm-1.5 dB Concentrator Maximum Gain Effective Area FOV Hemisphere +5 dB1.5 cm ² 60 ° Hemisphere +5 dB1.5 cm ² 60 ° Hemisphere +5 dB1.5 cm ² 60 ° Hemisphere +5 dB1.5 cm ² 60 ° Hemisphere +5 dB1.5 cm ² 60 ° Hemisphere +5 dB1.5 cm ² 60 ° Parking ECH _min × H _max × d _ec 1 vehicle1.5 × 3 × 3 m ³ 1 vehicle1.5 × 3 × 3 m ³ 1 vehicle1.5 × 3 × 3 m ³ 1 vehicle1.5 × 3 × 3 m ³ 1 vehicle1.5 × 3 × 3 m ³ 1 vehicle1.5 × 3 × 3 m ³ Wireless infrared link LOS-ND LOS-ND LOS-ND LOS-ND LOS-ND LOS-ND Modulation type OOK / NRZ OOK / NRZ OOK / NRZ OOK / NRZ OOK / NRZ OOK / NRZ Channel type IM / DD IM / DD IM / DD IM / DD IM / DD IM / DD Free space attenuation  -53 dB -53 dB -53 dB -53 dB -53 dB -53 dB

Communication space-train Perpendicular Bit rate 10 Mbps 100 Mbps 155 Mbps Infrared windows 810 nm 810 nm 810 nm Transmission power +7 dBm +12 dBm +13 dBm Power supply type R (ψ) FOV Extended 60 ° Extended 60 ° Extended 60 °

Receiver Effective Area FOV No EQ1.5 cm ² 60 ° No EQ1.5 cm ² 60 ° No EQ1.5 cm ² 60 ° Photodetector Area Sensitivity PIN1 cm ² 0.53 A / W PIN1 cm ² 0.53 A / W PIN1 cm ² 0.53 A / W Receiver Sensitivity to 13.5 dB Minimum S / N -40.5 dBm -35.5 dBm -34.5 dBm Optical Filter Bandwidth Attenuation Hemisphere 20 nm-1.5 dB Hemisphere 20 nm-1.5 dB Hemisphere 20 nm-1.5 dB Concentrator Maximum Gain Effective Area FOV Hemisphere +5 dB1.5 cm ² 60 ° Hemisphere +5 dB1.5 cm ² 60 ° Hemisphere +5 dB1.5 cm ² 60 ° Train ECH _min × H _max × d _ec 2 seats 0.5 × 1.5 × 1.5 m ³ 2 seats 0.5 × 1.5 × 1.5 m ³ 2 seats 0.5 × 1.5 × 1.5 m ³ Wireless infrared link LOS-ND LOS-ND LOS-ND Modulation type OOK / NRZ OOK / NRZ OOK / NRZ Channel type IM / DD IM / DD IM / DD Free space attenuation  -46.5 dB -46.5 dB -46.5 dB

Claims (14)

12. A base comprising transmitting and receiving means having transmitting and receiving means and adapted to exchange information with a remote terminal located within a defined area of arrival, wherein the known transmitting and receiving means is extended to the observer at an angle in excess of 100 milliradians. A base for wirelessly connecting a terminal to a communication network, comprising a transmitter provided with a light source. 2. The base of claim 1, wherein said known transmitter transmits information to a remote terminal at a high bit rate. 3. A terminal according to claim 1 or 2, wherein the base includes a light source position control means for achieving an optimum alignment of the transmitting and receiving means of the terminal located within the area of arrival of the light source and the base. Base for wireless access. The wireless connection of a terminal to a communication network according to claim 1 or 2, wherein the extended infrared light source comprises a laser emitting means and a transmitting diffuser means for diffusing the emitted light emitted by the laser emitting means. Base for. 5. A base according to claim 4, wherein said transmitting diffuser means is of holographic type. 3. The wireless connection system according to claim 1 or 2, wherein the extended infrared light source includes laser emitting means and reflecting means for diffusing the emitted light emitted by the laser emitting means. base. 3. A base for wirelessly connecting a terminal to a communication network according to claim 1 or 2, wherein said known transmitting and receiving means comprises an omnidirectional receiver. 8. A base according to claim 7, wherein said omnidirectional receiver comprises at least an omnidirectional concentrator. 9. A base according to claim 8, wherein said omnidirectional concentrator is hemispherical and comprises an optical filter. The base for wirelessly connecting a terminal to a communication network according to claim 8, wherein the omni-directional concentrator has an antireflective surface treatment. 12. A base comprising transmitting and receiving means having transmitting and receiving means and adapted to exchange information with a remote terminal located within a defined area of arrival, wherein the known transmitting and receiving means is extended to the observer at an angle in excess of 100 milliradians. A wireless communication method between a base and a remote terminal for connection with a communication network, characterized in that for transmitting information to the terminal through a transmitter provided with a light source. 12. The wireless communication between a base and a remote terminal for connection with a communication network according to claim 11, wherein the information is transmitted from the base to the terminal via an infrared link having direct, non-direct or hybrid line of sight. Way. 13. The method according to claim 11 or 12, wherein the transmitting and receiving means of the terminal transmits information to the base through an infrared link having direct or non-direct line of sight. Wireless communication method. 13. A method according to claim 11 or 12, wherein information is transmitted in burst mode between the terminal and the base.