CA2294792C - Data transmission method and data transmission system - Google Patents
Data transmission method and data transmission system Download PDFInfo
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- CA2294792C CA2294792C CA002294792A CA2294792A CA2294792C CA 2294792 C CA2294792 C CA 2294792C CA 002294792 A CA002294792 A CA 002294792A CA 2294792 A CA2294792 A CA 2294792A CA 2294792 C CA2294792 C CA 2294792C
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- data transmission
- transmission system
- network
- data
- image
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W28/00—Network traffic management; Network resource management
- H04W28/02—Traffic management, e.g. flow control or congestion control
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L65/00—Network arrangements, protocols or services for supporting real-time applications in data packet communication
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L12/00—Data switching networks
- H04L12/54—Store-and-forward switching systems
- H04L12/56—Packet switching systems
- H04L12/5601—Transfer mode dependent, e.g. ATM
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L43/00—Arrangements for monitoring or testing data switching networks
- H04L43/08—Monitoring or testing based on specific metrics, e.g. QoS, energy consumption or environmental parameters
- H04L43/0852—Delays
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W28/00—Network traffic management; Network resource management
- H04W28/02—Traffic management, e.g. flow control or congestion control
- H04W28/06—Optimizing the usage of the radio link, e.g. header compression, information sizing, discarding information
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- Engineering & Computer Science (AREA)
- Computer Networks & Wireless Communication (AREA)
- Signal Processing (AREA)
- Multimedia (AREA)
- Environmental & Geological Engineering (AREA)
- Communication Control (AREA)
- Data Exchanges In Wide-Area Networks (AREA)
- Mobile Radio Communication Systems (AREA)
- Selective Calling Equipment (AREA)
- Arrangements For Transmission Of Measured Signals (AREA)
Abstract
The invention relates to a data transmission method and system to be used for example in a mine. Data between a monitoring station (10 to 12) and a working machine (19) is transmitted digitally by a deterministic data transmission protocol, by means of which one or more working machine (19) can be controlled by teleoperation substantially in real time, and in which the data transmission delay is within predetermined limits.
Description
DATA TRANSMISSION METHOD AND DATA TRANSMISSION SYSTEM
FIELD OF THE INVENTION
The invention relates to a data transmission method for enclosed environments, such as a mine, the data transmission method being used in a data transmission system comprising one or more terminals and a network comprising at least one base station, a monitoring station and a backbone network, the data transmission system having a radio connection between the terminal and the base station and a bi-directional connection from the moni toring station to one or more working machines via the terminals, each of which is coupled to a working machine.
The invention further relates to a data transmission system to be used in enclosed environments, such as a mine, the data transmission system comprising one or more terminals and a network comprising at least one base station, a monitoring station and a backbone network, the data transmission systerh having a radio connection between the base station and the terminal and a bi-directional connection from the monitoring station to one or more ter-minals, each of which is coupled to a working machine.
BACKGROUND OF THE INVENTION
Automatically operating andlor remotely controlled machines, con-trolled and monitored either from above ground or from underground monitor-ing stations are associated with large-scale mining automation. Automation enables higher production, lower production costs and improved working envi-ronment for the staff. A communication network for transmitting multimedia information between production sites and monitoring stations is needed for teleoperating large machines and for other communication.
Present prior art mining data transmission systems are mainly ana-log. Their performance, security and capacity are, however, insufficient for extensive automation applications. In a typical system, video image, voice and data are transmitted analogously in channels having relatively slow transmis-sion rates. In addition, the signal of each information source is modulated to a dedicated carrier and the signals are distributed to the mine along a coaxial cable operating as the backbone network and having a radio connection to the machines. The radio connection is implemented either by antennae or the backbone network is partly or entirely based on leaky cables. Such a solution is disclosed in Canadian Patent Application No. 2,057,544, Communication system. A backbone network is typically several kilometres long, and the signals to be transmitted have to be amplified at given intervals to compensate for cable attenuation. Since amplifiers and other devices used for signal transmission are in practice slightly non-linear, signals form cross correlation results limiting connection quality. Particularly for this reason, numerous measurements and signal level tunings are needed when a backbone network is installed. This again causes network installation to be expensive and difficult to modify.
Patent publication US 5,697,067 discloses a communication system particularly for mines. The communication system of the publication uses radiating transmission lines, the aim being to reduce the intermodulation generated therein. The communication ~:ystem according to the publication is also able to transmit video images. Patent publication GB 2 288 300 discloses an image transmission system in which image coding operates as an encryption code simultaneously reducing the bandwidth required in image transmission. However, neither communication system provides real-time data transmission for teleoperation.
Digital data transmission systems provide better connections than analog systems. A typical problem in these systems is, however, that data transmission is not real-time. In systems based on e.g. LAN architecture, the LAN protocols are unable to ensure that the data to be transmitted is transmitted from the sender to the receiver always equally rapidly, or even that the data is transmitted at least within a predetermined period of time.
The data transmission delay of a typical prior art digital data transmission system is too high and varying for real-time teleoperation. Consequently, the use of digital systems in mines in particular is limited to non-real-time applications, i.e. applications with non-critical response times.
BRIEF DESCRIPTION OF THE INVENTION
The invention may provide a method and equipment complying with the method to solve the above problems. The solution of the invention enables the implementation of real-time transmission of multimedia information from a mining shaft to a monitoring station.
In accordance with one aspect of the invention, there is provided a data transmission method for enclosed environments, such as a mine, the data transmission method being used in a data transmission system comprising one or more terminals and a network comprising at least one base station, a monitoring station and a backbone nefiNOrk. The data transmission system has a radio connection between the teri~ninal and the base station and a bi-directional connection from the monitoring station to one or more working machines via the terminals, each of which are coupled to a working machine.
Data between the monitoring station and the terminal is transmitted digitally, and one or more working machines are controlled from the monitoring station by teleoperation substantially in real timE: by a deterministic data transmission protocol in which the data transmission delay is within predetermined limits.
The network may operate on the multicasting principle, whereby transmitted messages are forwarded to more than one units connected to the network.
Data transmission may be performed in the network as in an ATM
network.
The ATM network may operate on the multicasting principle by the ATM switches operating independently vrithout control.
The ATM network may operate on the multicasting principle so that the ATM switches are under centralized control.
Transmitted messages may be forwarded to all units connected to the network.
A connection between the terminal and the base station may be established by wireless spread spectrum signalling.
Data may be transmitted in broadband, and in data transmission one or more of the following information types are transmitted substantially simultaneously: image, voice, data.
3a Image, voice and data may be transmitted in packets.
Each terminal may have a fixed data transmission band, which in data transmission is allocated to image, voice and data.
Image and/or voice information may be compressed for data transmission.
Image information may be dynamically compressed.
Data transmission logical connections may be established between the units by a graphic user interface.
In accordance with another aspect of the invention, there is provided a data transmission system to be used in enclosed environments, such as a mine, the data transmission system comprising one or more terminals and a network comprising at least one base station, a monitoring station and a backbone network, the data transmission system having a radio connection between the base station and the tem~inal and a bi-directional connection from the monitoring station to one or more terminals which are coupled to a working machine. The data transmission system is arranged to transmit data digitally between the monitoring station and the terminal, and the data transmission system comprises a deterministic data transmission protocol by which one or more working machines can be controlled by teleoperation substantially in real time and in which the data transmission delay is within predetermined limits.
The network may be arranged to operate on the multicasting principle, whereby transmitted messages are 'forwarded to substantially all units connected to the network.
The network may be substantially an ATM network.
The ATM network may be arranged to operate on the multicasting principle, whereby the ATM switches operate independently without separate control.
The ATM network may be arranged to operate on the multicasting principle, whereby the ATM switches can be controlled in a centralized manner.
3b The data transmission system may be arranged to forward transmitted messages in a restricted manner to one or more units connected to the network.
The data transmission system may be arranged to establish a connection between the terminal and the base station by wireless spread spectrum signalling.
The data transmission system may be arranged to perform data transmission in broadband, and in dat2~ transmission the data transmission system is arranged to transmit substantially simultaneously one or more of the following information types: image, voice, data.
The data transmission system may be arranged to transmit image, voice and data in packets.
Each terminal may have a fixed data transmission band for image and/or voice and/or data transmission.
The data transmission system may be arranged to compress image and/or voice information for data transmission.
The data transmission system may be arranged to compress image information dynamically.
The data transmission system nnay be arranged to establish logical connections between the units by a graphic user interface.
In accordance with another aspect of the invention, there is provided a data transmission method for enclosed) environments, such as a mine, the data transmission method being usE:d in a data transmission system comprising one or more terminals and a network comprising at least one base station, one or more monitoring stations and a backbone network, the data transmission system having a radio connection between a terminal and a base station and a bi-directional connection from the monitoring station to one or more working machines via respective terminals, each of which is coupled to a working machine. The method involves digitally transmitting data between a monitoring station and one or more terminals, and one or more working machines to control the one or more ~nrorking machines from the monitoring station by teleoperation substantially in real time by a deterministic data 3c transmission protocol in which the data transmission delay is within predetermined limits.
The method further comprises operating the network on a multicasting principle, whereby transmitted messages are transmitted to more than one component of the data transmission systE:m.
Data may be transmitted on the nEawork in an ATM network protocol.
The method may further comprise operating ATM switches independently, without control, to cause the network to operate on a multicasting principle.
The method may further comprise ATM switches under centralized control to cause the network to operate an a multicasting principle.
The method may further comprise transmitting messages to cause the messages to be forwarded to all nodes of the network.
The method may further comprise establishing a connection between the terminal and the base station by wireless spread spectrum signalling.
The method may further compruse transmitting image, voice and/or data information substantially simultaneously in broadband.
The image, voice and/or data information may be transmitted in packets.
The method may further comprise: transmitting the image, voice and/or data information in a fixed data transmission band.
The method may further comprise compressing image and/or voice data information for transmission.
The method may further comprise dynamically compressing the image data.
The method may further comprise establishing logical connections between components of the system by a graphic user interface.
In accordance with another aspect of the invention, there is provided a data transmission system to be used in enclosed environments, such as a mine, the data transmission system comprises one or more terminals coupled to respective working machines and a network comprising at least one base station, a monitoring station and a bacb;bone network and a radio connection i i I I
3d between the base station and the one or more terminals and a bi-directional connection from the monitoring station to the one or more terminals, operably configured to transmit data digitally using a deterministic data transmission protocol by which one or more working machines can be controlled by teleoperation substantially in real time and in which the data transmission delay is within predetermined limits.
The network may be arranged to operate on the multicasting principle, whereby transmitted messages are transmitted to substantially all components of the system.
The network may include an ATM network.
The ATM network may include ~~TM switches configured to operate independently without separate control, and to cause the ATM network to operate on the multicasting principle.
The ATM network may include ATM switches configured to be controlled in a centralized manner, and to cause the ATM network to operate on the multicasting principle.
The backbone network may be operably configured to direct messages to different components of the system as. desired.
A connection may be established between a terminal and a base station of the data transmission sy~aem by wireless spread spectrum signalling.
The monitoring station and the one or more terminals may be operably configured to perform data transmission in broadband, and to transmit substantially simultaneously one or more of the following types of information:
image, voice, data.
The monitoring station and the one or more terminals may be operably configured to transmit image, voice and data information in packets.
Each terminal may be operably configured to transmit image, voice and/or data information in a fixed data transmission band.
The data transmission system further comprises a compressor operably configured to compress image and/or voice information for data transmission.
3e The compressor may be operably configured to compress image information dynamically.
The data transmission system further comprises a graphical user interface operably configured to establish logical connections between components of the system.
BRIEF DESCRIPTION OF THE DRAWINGS
In the following the invention will be described in greater detail in association with preferred embodiments with reference to the accompanying drawings, in which Figure 1 shows a data transmission system;
Figure 2 shows a packet used in data transmission;
Figure 3 shows a working machine connected to a data transmission system;
Figure 4 shows a monitoring station, and Figure 5 shows a protocol stack.
DETAILED DESCRIPTION OF THE INVENTION
The solution of the invention is particularly suitable for use in a mine, but is not, however, restricted therei:o. Other application areas for the invention include tunnels, buildings, open-cast mines and areas involving critical security aspects (nuclear plants, mine clearing). The basic idea of the invention is to provide transparent point-to-point type data connects between terminals and monitoring stations. The monitoring stations and terminals pro-vide an interface for connecting peripheral devices, such as remote control desks, computers, cameras and other devices.
The digital broadband data transmission system of the invention is well suited to the teleoperation and monitoring of heavy mining machines. Let us study the solution of the invention by means of the example in Figure 1.
The system comprises in a network 20 at lest one monitoring station 10 to 12, a network connection 13, switch means 14, a main cable 15, another network connection 16 and base stations 17. The system further comprises terminals 18, coupled to working machines 19 to enable control and monitoring. The network connection 13, the switch means 14 and the main cable 15 constitute the backbone network. The minimum configuration of the backbone network of the invention comprises only a main cable 15 between a monitoring station 10 to 12 and a base station 17; a radio connection can be used instead of the main cable. Consequently the network 20 only comprises a monitoring station 10 to 12, the backbone network (the main cable 15 or a radio connection) and a base station 17. Data transmission is digital between the monitoring station 10 to 12 and the working machine 19 in the data transmission system of the invention. The data transmission system further comprises a deterministic data transmission protocol, by means of which one or more working machines 19 can be controlled from the monitoring station 10 to 12 by teleoperation sub-stantially in real time, since by means of the data transmission protocol, the data transmission delay remains within predetermined limits irrespective of the load. Real time refers to operation taking place approximately in sync with the process. In the solution of the invention, the highest data transmission delay is preferably less than 10 ms.
The backbone network, composed of the cables 13, 15 and 16 and the switches 14 serves as the backbone of the network 20, which operates preferably on a multicasting principle, whereby transmitted messages are for-warded to more than one units connected to the network. In this event, a mes-sage sent from e.g. the monitoring station 10 first propagates to the switch 14, which sends it to the monitoring stations 11 and 12, and further to the main cable 15, from where the message propagates to all units 14, 17, 18 and 19.
In stead of transmitting the messages to all units, the number of message re-ceivers can also be limited. In this case the monitoring station 12 can be e.g.
in a bi-directional connection to only the right-hand terminals 18 and working WO 99/01943 PCTlFI98/00564 machines 19. In this case the monitoring station 12 and the right-hand termi-nals 18 and working machines 19 do not preferably see the rest of the system.
Other devices (e.g. terminals, sensors etc.), not visible in the system, but using it, can be connected to the backbone network by similarly restricting multi-5 casting connections.
The network 20 is preferably an ATM network {Asynchronous Transfer Mode) or the like. The ATM network typically enables a data trans-mission rate of 155 Mbps. One connection between a working machine 19 and a monitoring station 10 to 12 requires a data transmission rate of e.g. 1 Mbps, and consequently an ATM backbone network enables the simultaneous monitoring and control of at least several dozens of working machines 19 from each monitoring station 10 to 12.
In a preferred embodiment of the invention, the ATM backbone network operates on the multicasting principle by the ATM routing switches 14 operating independently without separate control. In this event the switches direct a received message to all units of the data transmission system. This deviates somewhat from the conventional operation of ATM network switches.
The ATM switches are programmed such that packets coming from one port are sent as such, without changing the address and data fields, to all other ports. The multicasting principle simplifies the system since it dispenses with the extremely heavy signalling which is currently incompletely determined in e.g. the ATM network.
Instead of operating independently, the ATM backbone network can operate on the multicasting principle by the ATM switches 14 being centrally controllable. The switches 14 are preferably controlled by signalling from the monitoring stations 10 to 12. In this case the switches 14 direct the messages to different units as desired. This allows unnecessary data transmission to be reduced. For example, the monitoring station 10 can be first in a multicasting connection only to the right-hand units of Figure 1, and later to only the lower units in Figure 1. In this event the arrangement is invisible to the rest of the system, and the other parts of the system are unable to see this arrangement.
The switches 14 are preferably FSR switches (Frame Synchronous Ring). A
prior art FSR switch is based on ring topology and is simple and efficient. An FSR switch is suitable for broadband switch applications. FSR switches that are suitable for the ATM interface also enable e.g. the use of optical fibre at the rates of 155 Mbps (SDH/STM-1 ) and 100 Mbps (TAXI) and the use of a WO 99/01943 PC'T/FI98/00564 metal conductor at the rates of 34 Mbps (PDH/E3) and 2 Mbps (PDHIE1 ).
The data transmission system of the invention establishes a con-nection between a terminal and a base station preferably by wireless spread spectrum signalling, although the connection can also be established without the spread spectrum technique. In spread spectrum technique, a narrowband user data signal is modulated to a broader band than that required by the data signal. In prior art solutions where the signal of each transmitter is modulated to its own carrier, the terminal amplifier of the monitoring station 10 to 12 and possible intermediate repeaters in the network 20 have to process a multi-carrier signal. This causes an intermodulation problem. The power of each carrier has to be kept low to reduce intermodulation, resulting in short signal range. In a mine, radio signal scattering and reflection causes multipath propagation and fading, leading to major problems in prior art solutions. In the inventive solution the intermodulation problem is eliminated since video, data and audio signals are digitized and multiplexed to a common bit stream as early as at the terminal, whereby preferably only one carrier is required for each terminal. Since the intermodulation problem is eliminated, higher trans-mission powers can be used, resulting in longer signal ranges. Since the range is longer, cabling and antennae do no longer have to be installed in the furthermost comers of production areas. The spread spectrum technique again causes the effect of multipath propagation to decrease. In addition, data is transmitted digitally in base band in the network, whereby no intermodula-tion is created.
The data transmission system is arranged to perform data trans mission in broadband, the data transmission system comprising a plurality of multimedia channels so that the system in principle enables an almost unlim ited number of connections between a mining shaft/terminal and a ground level/monitoring station. In addition to voice and speech signals, the broad band feature thus enables the simultaneous transmission and reception of video, data and control signals both in the mining shaft and above ground. The data transmission system thus transmits one or more of the following informa-tion types substantially simultaneously: image, voice, data. Image information can be used to control the performance of a working machine 19, to control a working machine 19 from one tunnel to another to the working site, etc. Voice information can contain e.g. motor sounds, allowing the monitoring station 10 to 12 to hear if the engine is operating correctly etc. Voice information also includes human speech from the monitoring station 10 to 12 to the mine or from the mine to the monitoring station 10 to 12. The data and control signals are used e.g. to monitor the condition of working machines by sensors dis-posed in the working machines and to control the working machines 19.
The data transmission system transmits image, voice and data preferably as packets, which are preferably ATM cells or the like. The packets are transmitted unchanged across the radio interface. The base station 17 and the terminal 18 can have radio communication with one another in accordance with the FDMA (Frequency Division Multiple Access), TDMA (Time Division Multiple Access), SDMA (Space Division Multiple Access) or CDMA (Code Division Multiple Access) methods. The CSMA/CD method (Carrier Sense Multiple Access with Collision Detection) can also be used, but one has to en-sure that the operating system is sufficiently rapid for real-time operation even in data collision. The system uses e.g. 1 to 50 MHz bandwidths. In FDMA, us-ers are distinguished from each other on the basis of the frequency band, in TDMA users transmit in different timeslots, in SDMA signals are directed to the receiver, and in CDMA users are distinguished from each other by means of a spreading code.
Each terminal has a fixed data transmission band which the data transmission system allocates to image, voice and data. With a plurality of data and control signals, less data transmission capacity is left for image and voice. In the inventive solution, image and voice are compressed digitally in the data transmission system to enable more efficient data transmission. By compression the bandwidth required for transmitting a video signal can be dropped even 50 times smaller as compared with an uncompressed video sig-nal, without impairing image quality. Data and control signals are not com-pressed in the inventive solution. The solution of the invention allows any prior art image compression method. In the data transmission system image is preferably compressed dynamically, that is, if the data transmission need ex-ceeds the available capacity, a video signal is compressed more and more - until the data transmission need required by the video signal corresponds to the available amount. This provides a data transmission band that is sufficient in all situations and ensures transmission by a deterministic delay for high-priority data, such as control data. Transmission capacity is not unnecessarily reserved for any information, although the amount of information to be trans-ferred varies. The characteristics, i.e. information contents, of. an image are consequently reduced in compression, if need be, to an extent that the infor-mation therein always fits into the remaining data transmission band. This en-sures an optimal image quality.
In the inventive solution, image compression is assisted e.g. by digital adapted median filtering of a video image, in which a reference value is generated for the pixel block to be processed. The value of each pixel of a pixel block is compared with the reference value, and if the pixel value devi ates from the reference value by more than a threshold value, the pixel value is replaced by the reference value. In dynamic compression the magnitude of the threshold value can be preferably adapted according to the available data transmission capacitylbandwidth.
In packet-mode transmission a fixed bandwidth means that each terminal transmits in a time unit a fixed number of packets, into which image, voice and data have to be placed. This way the information contents of an im-age are reduced, if needed, during compression to a degree that its informa-tion always fits into the space left in each packet by data and voice. The data transmission protocol used in the inventive solution is also optimized for data transmission across the radio/backbone network interface. In this event packet-mode presentation of the data remains unchanged in the entire data transmission system.
A packet, shown in Figure 2, resembles an ATM cell and comprises an MT/ID part 21, which is a machine identifier, and a data part 22. The entire packet comprises 48 bytes. Data is divided into N fields, each comprising a header 23 and a data part 24. Each header comprises a pipe number 25 and data length in bytes 26. One byte typically comprises 8 bits. A packet com-prises data of 7 different pipes and general control data of the entire system, transferred in pipe 0.
The data transmission system establishes logical connections be-tween units by means of a graphic user interface. A logical connection means that a physical connection, e.g. a conductor, changes with time, but the con-nection, or the actual data transmission itself does not change nor is disturbed by changes in the physical connection. Typical graphic user interfaces include Windows and X-windows. A graphic user interface provides a user distinct in-formation on the units connected to the network, disturbances in communica-tion, hardware failures and enables flexible establishment of logical connec-tions between the units.
FIELD OF THE INVENTION
The invention relates to a data transmission method for enclosed environments, such as a mine, the data transmission method being used in a data transmission system comprising one or more terminals and a network comprising at least one base station, a monitoring station and a backbone network, the data transmission system having a radio connection between the terminal and the base station and a bi-directional connection from the moni toring station to one or more working machines via the terminals, each of which is coupled to a working machine.
The invention further relates to a data transmission system to be used in enclosed environments, such as a mine, the data transmission system comprising one or more terminals and a network comprising at least one base station, a monitoring station and a backbone network, the data transmission systerh having a radio connection between the base station and the terminal and a bi-directional connection from the monitoring station to one or more ter-minals, each of which is coupled to a working machine.
BACKGROUND OF THE INVENTION
Automatically operating andlor remotely controlled machines, con-trolled and monitored either from above ground or from underground monitor-ing stations are associated with large-scale mining automation. Automation enables higher production, lower production costs and improved working envi-ronment for the staff. A communication network for transmitting multimedia information between production sites and monitoring stations is needed for teleoperating large machines and for other communication.
Present prior art mining data transmission systems are mainly ana-log. Their performance, security and capacity are, however, insufficient for extensive automation applications. In a typical system, video image, voice and data are transmitted analogously in channels having relatively slow transmis-sion rates. In addition, the signal of each information source is modulated to a dedicated carrier and the signals are distributed to the mine along a coaxial cable operating as the backbone network and having a radio connection to the machines. The radio connection is implemented either by antennae or the backbone network is partly or entirely based on leaky cables. Such a solution is disclosed in Canadian Patent Application No. 2,057,544, Communication system. A backbone network is typically several kilometres long, and the signals to be transmitted have to be amplified at given intervals to compensate for cable attenuation. Since amplifiers and other devices used for signal transmission are in practice slightly non-linear, signals form cross correlation results limiting connection quality. Particularly for this reason, numerous measurements and signal level tunings are needed when a backbone network is installed. This again causes network installation to be expensive and difficult to modify.
Patent publication US 5,697,067 discloses a communication system particularly for mines. The communication system of the publication uses radiating transmission lines, the aim being to reduce the intermodulation generated therein. The communication ~:ystem according to the publication is also able to transmit video images. Patent publication GB 2 288 300 discloses an image transmission system in which image coding operates as an encryption code simultaneously reducing the bandwidth required in image transmission. However, neither communication system provides real-time data transmission for teleoperation.
Digital data transmission systems provide better connections than analog systems. A typical problem in these systems is, however, that data transmission is not real-time. In systems based on e.g. LAN architecture, the LAN protocols are unable to ensure that the data to be transmitted is transmitted from the sender to the receiver always equally rapidly, or even that the data is transmitted at least within a predetermined period of time.
The data transmission delay of a typical prior art digital data transmission system is too high and varying for real-time teleoperation. Consequently, the use of digital systems in mines in particular is limited to non-real-time applications, i.e. applications with non-critical response times.
BRIEF DESCRIPTION OF THE INVENTION
The invention may provide a method and equipment complying with the method to solve the above problems. The solution of the invention enables the implementation of real-time transmission of multimedia information from a mining shaft to a monitoring station.
In accordance with one aspect of the invention, there is provided a data transmission method for enclosed environments, such as a mine, the data transmission method being used in a data transmission system comprising one or more terminals and a network comprising at least one base station, a monitoring station and a backbone nefiNOrk. The data transmission system has a radio connection between the teri~ninal and the base station and a bi-directional connection from the monitoring station to one or more working machines via the terminals, each of which are coupled to a working machine.
Data between the monitoring station and the terminal is transmitted digitally, and one or more working machines are controlled from the monitoring station by teleoperation substantially in real timE: by a deterministic data transmission protocol in which the data transmission delay is within predetermined limits.
The network may operate on the multicasting principle, whereby transmitted messages are forwarded to more than one units connected to the network.
Data transmission may be performed in the network as in an ATM
network.
The ATM network may operate on the multicasting principle by the ATM switches operating independently vrithout control.
The ATM network may operate on the multicasting principle so that the ATM switches are under centralized control.
Transmitted messages may be forwarded to all units connected to the network.
A connection between the terminal and the base station may be established by wireless spread spectrum signalling.
Data may be transmitted in broadband, and in data transmission one or more of the following information types are transmitted substantially simultaneously: image, voice, data.
3a Image, voice and data may be transmitted in packets.
Each terminal may have a fixed data transmission band, which in data transmission is allocated to image, voice and data.
Image and/or voice information may be compressed for data transmission.
Image information may be dynamically compressed.
Data transmission logical connections may be established between the units by a graphic user interface.
In accordance with another aspect of the invention, there is provided a data transmission system to be used in enclosed environments, such as a mine, the data transmission system comprising one or more terminals and a network comprising at least one base station, a monitoring station and a backbone network, the data transmission system having a radio connection between the base station and the tem~inal and a bi-directional connection from the monitoring station to one or more terminals which are coupled to a working machine. The data transmission system is arranged to transmit data digitally between the monitoring station and the terminal, and the data transmission system comprises a deterministic data transmission protocol by which one or more working machines can be controlled by teleoperation substantially in real time and in which the data transmission delay is within predetermined limits.
The network may be arranged to operate on the multicasting principle, whereby transmitted messages are 'forwarded to substantially all units connected to the network.
The network may be substantially an ATM network.
The ATM network may be arranged to operate on the multicasting principle, whereby the ATM switches operate independently without separate control.
The ATM network may be arranged to operate on the multicasting principle, whereby the ATM switches can be controlled in a centralized manner.
3b The data transmission system may be arranged to forward transmitted messages in a restricted manner to one or more units connected to the network.
The data transmission system may be arranged to establish a connection between the terminal and the base station by wireless spread spectrum signalling.
The data transmission system may be arranged to perform data transmission in broadband, and in dat2~ transmission the data transmission system is arranged to transmit substantially simultaneously one or more of the following information types: image, voice, data.
The data transmission system may be arranged to transmit image, voice and data in packets.
Each terminal may have a fixed data transmission band for image and/or voice and/or data transmission.
The data transmission system may be arranged to compress image and/or voice information for data transmission.
The data transmission system may be arranged to compress image information dynamically.
The data transmission system nnay be arranged to establish logical connections between the units by a graphic user interface.
In accordance with another aspect of the invention, there is provided a data transmission method for enclosed) environments, such as a mine, the data transmission method being usE:d in a data transmission system comprising one or more terminals and a network comprising at least one base station, one or more monitoring stations and a backbone network, the data transmission system having a radio connection between a terminal and a base station and a bi-directional connection from the monitoring station to one or more working machines via respective terminals, each of which is coupled to a working machine. The method involves digitally transmitting data between a monitoring station and one or more terminals, and one or more working machines to control the one or more ~nrorking machines from the monitoring station by teleoperation substantially in real time by a deterministic data 3c transmission protocol in which the data transmission delay is within predetermined limits.
The method further comprises operating the network on a multicasting principle, whereby transmitted messages are transmitted to more than one component of the data transmission systE:m.
Data may be transmitted on the nEawork in an ATM network protocol.
The method may further comprise operating ATM switches independently, without control, to cause the network to operate on a multicasting principle.
The method may further comprise ATM switches under centralized control to cause the network to operate an a multicasting principle.
The method may further comprise transmitting messages to cause the messages to be forwarded to all nodes of the network.
The method may further comprise establishing a connection between the terminal and the base station by wireless spread spectrum signalling.
The method may further compruse transmitting image, voice and/or data information substantially simultaneously in broadband.
The image, voice and/or data information may be transmitted in packets.
The method may further comprise: transmitting the image, voice and/or data information in a fixed data transmission band.
The method may further comprise compressing image and/or voice data information for transmission.
The method may further comprise dynamically compressing the image data.
The method may further comprise establishing logical connections between components of the system by a graphic user interface.
In accordance with another aspect of the invention, there is provided a data transmission system to be used in enclosed environments, such as a mine, the data transmission system comprises one or more terminals coupled to respective working machines and a network comprising at least one base station, a monitoring station and a bacb;bone network and a radio connection i i I I
3d between the base station and the one or more terminals and a bi-directional connection from the monitoring station to the one or more terminals, operably configured to transmit data digitally using a deterministic data transmission protocol by which one or more working machines can be controlled by teleoperation substantially in real time and in which the data transmission delay is within predetermined limits.
The network may be arranged to operate on the multicasting principle, whereby transmitted messages are transmitted to substantially all components of the system.
The network may include an ATM network.
The ATM network may include ~~TM switches configured to operate independently without separate control, and to cause the ATM network to operate on the multicasting principle.
The ATM network may include ATM switches configured to be controlled in a centralized manner, and to cause the ATM network to operate on the multicasting principle.
The backbone network may be operably configured to direct messages to different components of the system as. desired.
A connection may be established between a terminal and a base station of the data transmission sy~aem by wireless spread spectrum signalling.
The monitoring station and the one or more terminals may be operably configured to perform data transmission in broadband, and to transmit substantially simultaneously one or more of the following types of information:
image, voice, data.
The monitoring station and the one or more terminals may be operably configured to transmit image, voice and data information in packets.
Each terminal may be operably configured to transmit image, voice and/or data information in a fixed data transmission band.
The data transmission system further comprises a compressor operably configured to compress image and/or voice information for data transmission.
3e The compressor may be operably configured to compress image information dynamically.
The data transmission system further comprises a graphical user interface operably configured to establish logical connections between components of the system.
BRIEF DESCRIPTION OF THE DRAWINGS
In the following the invention will be described in greater detail in association with preferred embodiments with reference to the accompanying drawings, in which Figure 1 shows a data transmission system;
Figure 2 shows a packet used in data transmission;
Figure 3 shows a working machine connected to a data transmission system;
Figure 4 shows a monitoring station, and Figure 5 shows a protocol stack.
DETAILED DESCRIPTION OF THE INVENTION
The solution of the invention is particularly suitable for use in a mine, but is not, however, restricted therei:o. Other application areas for the invention include tunnels, buildings, open-cast mines and areas involving critical security aspects (nuclear plants, mine clearing). The basic idea of the invention is to provide transparent point-to-point type data connects between terminals and monitoring stations. The monitoring stations and terminals pro-vide an interface for connecting peripheral devices, such as remote control desks, computers, cameras and other devices.
The digital broadband data transmission system of the invention is well suited to the teleoperation and monitoring of heavy mining machines. Let us study the solution of the invention by means of the example in Figure 1.
The system comprises in a network 20 at lest one monitoring station 10 to 12, a network connection 13, switch means 14, a main cable 15, another network connection 16 and base stations 17. The system further comprises terminals 18, coupled to working machines 19 to enable control and monitoring. The network connection 13, the switch means 14 and the main cable 15 constitute the backbone network. The minimum configuration of the backbone network of the invention comprises only a main cable 15 between a monitoring station 10 to 12 and a base station 17; a radio connection can be used instead of the main cable. Consequently the network 20 only comprises a monitoring station 10 to 12, the backbone network (the main cable 15 or a radio connection) and a base station 17. Data transmission is digital between the monitoring station 10 to 12 and the working machine 19 in the data transmission system of the invention. The data transmission system further comprises a deterministic data transmission protocol, by means of which one or more working machines 19 can be controlled from the monitoring station 10 to 12 by teleoperation sub-stantially in real time, since by means of the data transmission protocol, the data transmission delay remains within predetermined limits irrespective of the load. Real time refers to operation taking place approximately in sync with the process. In the solution of the invention, the highest data transmission delay is preferably less than 10 ms.
The backbone network, composed of the cables 13, 15 and 16 and the switches 14 serves as the backbone of the network 20, which operates preferably on a multicasting principle, whereby transmitted messages are for-warded to more than one units connected to the network. In this event, a mes-sage sent from e.g. the monitoring station 10 first propagates to the switch 14, which sends it to the monitoring stations 11 and 12, and further to the main cable 15, from where the message propagates to all units 14, 17, 18 and 19.
In stead of transmitting the messages to all units, the number of message re-ceivers can also be limited. In this case the monitoring station 12 can be e.g.
in a bi-directional connection to only the right-hand terminals 18 and working WO 99/01943 PCTlFI98/00564 machines 19. In this case the monitoring station 12 and the right-hand termi-nals 18 and working machines 19 do not preferably see the rest of the system.
Other devices (e.g. terminals, sensors etc.), not visible in the system, but using it, can be connected to the backbone network by similarly restricting multi-5 casting connections.
The network 20 is preferably an ATM network {Asynchronous Transfer Mode) or the like. The ATM network typically enables a data trans-mission rate of 155 Mbps. One connection between a working machine 19 and a monitoring station 10 to 12 requires a data transmission rate of e.g. 1 Mbps, and consequently an ATM backbone network enables the simultaneous monitoring and control of at least several dozens of working machines 19 from each monitoring station 10 to 12.
In a preferred embodiment of the invention, the ATM backbone network operates on the multicasting principle by the ATM routing switches 14 operating independently without separate control. In this event the switches direct a received message to all units of the data transmission system. This deviates somewhat from the conventional operation of ATM network switches.
The ATM switches are programmed such that packets coming from one port are sent as such, without changing the address and data fields, to all other ports. The multicasting principle simplifies the system since it dispenses with the extremely heavy signalling which is currently incompletely determined in e.g. the ATM network.
Instead of operating independently, the ATM backbone network can operate on the multicasting principle by the ATM switches 14 being centrally controllable. The switches 14 are preferably controlled by signalling from the monitoring stations 10 to 12. In this case the switches 14 direct the messages to different units as desired. This allows unnecessary data transmission to be reduced. For example, the monitoring station 10 can be first in a multicasting connection only to the right-hand units of Figure 1, and later to only the lower units in Figure 1. In this event the arrangement is invisible to the rest of the system, and the other parts of the system are unable to see this arrangement.
The switches 14 are preferably FSR switches (Frame Synchronous Ring). A
prior art FSR switch is based on ring topology and is simple and efficient. An FSR switch is suitable for broadband switch applications. FSR switches that are suitable for the ATM interface also enable e.g. the use of optical fibre at the rates of 155 Mbps (SDH/STM-1 ) and 100 Mbps (TAXI) and the use of a WO 99/01943 PC'T/FI98/00564 metal conductor at the rates of 34 Mbps (PDH/E3) and 2 Mbps (PDHIE1 ).
The data transmission system of the invention establishes a con-nection between a terminal and a base station preferably by wireless spread spectrum signalling, although the connection can also be established without the spread spectrum technique. In spread spectrum technique, a narrowband user data signal is modulated to a broader band than that required by the data signal. In prior art solutions where the signal of each transmitter is modulated to its own carrier, the terminal amplifier of the monitoring station 10 to 12 and possible intermediate repeaters in the network 20 have to process a multi-carrier signal. This causes an intermodulation problem. The power of each carrier has to be kept low to reduce intermodulation, resulting in short signal range. In a mine, radio signal scattering and reflection causes multipath propagation and fading, leading to major problems in prior art solutions. In the inventive solution the intermodulation problem is eliminated since video, data and audio signals are digitized and multiplexed to a common bit stream as early as at the terminal, whereby preferably only one carrier is required for each terminal. Since the intermodulation problem is eliminated, higher trans-mission powers can be used, resulting in longer signal ranges. Since the range is longer, cabling and antennae do no longer have to be installed in the furthermost comers of production areas. The spread spectrum technique again causes the effect of multipath propagation to decrease. In addition, data is transmitted digitally in base band in the network, whereby no intermodula-tion is created.
The data transmission system is arranged to perform data trans mission in broadband, the data transmission system comprising a plurality of multimedia channels so that the system in principle enables an almost unlim ited number of connections between a mining shaft/terminal and a ground level/monitoring station. In addition to voice and speech signals, the broad band feature thus enables the simultaneous transmission and reception of video, data and control signals both in the mining shaft and above ground. The data transmission system thus transmits one or more of the following informa-tion types substantially simultaneously: image, voice, data. Image information can be used to control the performance of a working machine 19, to control a working machine 19 from one tunnel to another to the working site, etc. Voice information can contain e.g. motor sounds, allowing the monitoring station 10 to 12 to hear if the engine is operating correctly etc. Voice information also includes human speech from the monitoring station 10 to 12 to the mine or from the mine to the monitoring station 10 to 12. The data and control signals are used e.g. to monitor the condition of working machines by sensors dis-posed in the working machines and to control the working machines 19.
The data transmission system transmits image, voice and data preferably as packets, which are preferably ATM cells or the like. The packets are transmitted unchanged across the radio interface. The base station 17 and the terminal 18 can have radio communication with one another in accordance with the FDMA (Frequency Division Multiple Access), TDMA (Time Division Multiple Access), SDMA (Space Division Multiple Access) or CDMA (Code Division Multiple Access) methods. The CSMA/CD method (Carrier Sense Multiple Access with Collision Detection) can also be used, but one has to en-sure that the operating system is sufficiently rapid for real-time operation even in data collision. The system uses e.g. 1 to 50 MHz bandwidths. In FDMA, us-ers are distinguished from each other on the basis of the frequency band, in TDMA users transmit in different timeslots, in SDMA signals are directed to the receiver, and in CDMA users are distinguished from each other by means of a spreading code.
Each terminal has a fixed data transmission band which the data transmission system allocates to image, voice and data. With a plurality of data and control signals, less data transmission capacity is left for image and voice. In the inventive solution, image and voice are compressed digitally in the data transmission system to enable more efficient data transmission. By compression the bandwidth required for transmitting a video signal can be dropped even 50 times smaller as compared with an uncompressed video sig-nal, without impairing image quality. Data and control signals are not com-pressed in the inventive solution. The solution of the invention allows any prior art image compression method. In the data transmission system image is preferably compressed dynamically, that is, if the data transmission need ex-ceeds the available capacity, a video signal is compressed more and more - until the data transmission need required by the video signal corresponds to the available amount. This provides a data transmission band that is sufficient in all situations and ensures transmission by a deterministic delay for high-priority data, such as control data. Transmission capacity is not unnecessarily reserved for any information, although the amount of information to be trans-ferred varies. The characteristics, i.e. information contents, of. an image are consequently reduced in compression, if need be, to an extent that the infor-mation therein always fits into the remaining data transmission band. This en-sures an optimal image quality.
In the inventive solution, image compression is assisted e.g. by digital adapted median filtering of a video image, in which a reference value is generated for the pixel block to be processed. The value of each pixel of a pixel block is compared with the reference value, and if the pixel value devi ates from the reference value by more than a threshold value, the pixel value is replaced by the reference value. In dynamic compression the magnitude of the threshold value can be preferably adapted according to the available data transmission capacitylbandwidth.
In packet-mode transmission a fixed bandwidth means that each terminal transmits in a time unit a fixed number of packets, into which image, voice and data have to be placed. This way the information contents of an im-age are reduced, if needed, during compression to a degree that its informa-tion always fits into the space left in each packet by data and voice. The data transmission protocol used in the inventive solution is also optimized for data transmission across the radio/backbone network interface. In this event packet-mode presentation of the data remains unchanged in the entire data transmission system.
A packet, shown in Figure 2, resembles an ATM cell and comprises an MT/ID part 21, which is a machine identifier, and a data part 22. The entire packet comprises 48 bytes. Data is divided into N fields, each comprising a header 23 and a data part 24. Each header comprises a pipe number 25 and data length in bytes 26. One byte typically comprises 8 bits. A packet com-prises data of 7 different pipes and general control data of the entire system, transferred in pipe 0.
The data transmission system establishes logical connections be-tween units by means of a graphic user interface. A logical connection means that a physical connection, e.g. a conductor, changes with time, but the con-nection, or the actual data transmission itself does not change nor is disturbed by changes in the physical connection. Typical graphic user interfaces include Windows and X-windows. A graphic user interface provides a user distinct in-formation on the units connected to the network, disturbances in communica-tion, hardware failures and enables flexible establishment of logical connec-tions between the units.
Remote control desks, computers, cameras and other devices are connected to the inventive data transmission system e.g. by the following in-terfaces 13 and 16: RS-232, RS-4.85, Profibus and Ethernet LAN.
Figure 3 shows a working machine comprising a terminal 18,. the actual machine 19, a camera 31, a microphone 32, a speaker 33 and sensors 34. The camera 19 can preferably be turned in different directions vertically and horizontally. The camera 19 can be any monochrome or colour camera.
The microphone 32 and speaker 33 of the terminal 18 allow bi-directional voice transmission. The sensor 34 measures some magnitude significant to the operation of the machine 19, e.g. temperature, and signals the information to the monitoring station 10 to 12 at least in malfunction.
Figure 4 shows a monitoring station. The monitoring station 10 to 12 comprises a monitor 41, displaying the image conveyed by the camera 31 and information on system status presented by the graphic user interface, and working machine control means 42. The monitoring station 10 to 12 also com-prises a microphone 43 and a speaker 44 which enable voice transmission.
Let us study the deterministic data transmission protocol of the in-vention in greater detail by means of the OSI model (Open Systems Intercon nection). Deterministic refers to a predetermined data transmission delay irre spective of the load, and is preferably applied only to real-time user informa tion, not to intra-system signalling. The compression of a video image typically takes 120 to 150 ms, a few dozens of milliseconds being left for data trans-mission when the attempt is to reach a total delay of 150 to 200 ms enabling a substantially real-time remote control. Figure 5 shows a protocol stack com-prising a physical layer 51, an I/O layer 52, an MAC layer (Medium Access Control) 53, an I/O routing layer 54 and a control layer 55. Above these is an application layer 56: The physical layer 51 provides the radio interface, the ATM interface and input and output ports for data. The I/O layer 52 provides data packeting, routing of input and output data between pipes 0 to 7, and ini-tialization and control of the hardware. The MAC layer 53 provides connection set-up, automatic identification of adjacent network nodes, transmission of control data in pipe 0, error control, retransmission, etc. The term pipe refers to virtual pipes formed between the units between different input and output ports. The control layer 55 provides connection set-up between the units of the system, automatic identification of the units connected to the system, and transmission and reception of control data between the units by means of the WO 99!01943 PCT/FI98/00564 MAC. Intra-system control data (pipe 0) is routed in the units at the MAC
layer 53 and further, if needed, at the control layer 55.
A deterministic protocol is based on five features. All user data, e.g.
remote control commands, image information or voice information, is assem-5 bled into packets and routed directly at the UO routing layer to the desired in-terface (e.g. the radio interface). The terminal or the monitoring station sends the packet at predetermined intervals, e.g. 0.4 ms, and all data received from the I/O (pipes 1 to 7) after the previous packet is included in the packet.
The base station routes a packet coming from the terminal via the radio interface 10 directly at the IIO routing layer 54 to the ATM interface towards the monitoring station. The monitoring station or terminal receiving the packet disassembles it and routes the user data directly to the desired Il0 port at the I/O routing layer 54 (pipes 1 to 7). No error detection methods or retransmissions are used in user data transmission. Error correction and retransmission can, however, be arranged at the remote control desk of the monitoring station or in the machine to be controlled. The deterministic feature is also facilitated by the network preferably operating as a switched network as does ATM in which data colli-sions do not occur. The network has a very high capacity and its switches are of non-blocking type.
Pipes, which are always connected to a physical input or output port, are formed between the devices of the data transmission system at the I/O layer 52. The port can be a serial port, a video unit or another device of the data transmission system. On the basis of control information received from the upper layers, the I/O layer 52 recognizes the receiver of the data coming from the different pipes, whereby the data can be immediately forwarded with-out it having to circulate via the upper layers. Since the terminal and the monitoring station send a packet at regular intervals, the data accumulated from all I/O ports after the previous packet is assembled to the packet. The packet is transferred back to the physical layer either to the radio interface or the ATM interface. At the radio interface, an one-byte preamble, serving to identify and synchronize the packet at the receiver, is inserted at the front of the packet. At the ATM interface, a five-byte field, containing a connection identifier and additional information on connection type, is inserted at the front of the packet. The identifiers inserted by the physical layer are invisible to the IIO layer 52. The base station receives the packets from the ATM network and routes the data from different pipes in a predetermined manner. Control data (pipe 0) is transferred to the upper layers, and user data (pipes 1 to 7) is transferred directly from the I/O layer 52 to the physical layer at the radio in-terface. In this way connections are established, the IIO layer 52 is set and the system is controlled at the upper layers. The principle is that the control layer knows the entire transmission system, the MAC layer knows the adjacent nodes, and the IIO layer 52 knows the routing of the data conveyed in the dif ferent pipes. All the time, the highest layer in which user data is transferred is the IIO layer 52, ensuring the deterministic data transmission of the invention.
Although the invention has been described above with reference to the example according to the attached drawings, it is obvious that it is not re stricted thereto, but can be modified in a variety of ways within the inventive idea disclosed in the attached claims.
Figure 3 shows a working machine comprising a terminal 18,. the actual machine 19, a camera 31, a microphone 32, a speaker 33 and sensors 34. The camera 19 can preferably be turned in different directions vertically and horizontally. The camera 19 can be any monochrome or colour camera.
The microphone 32 and speaker 33 of the terminal 18 allow bi-directional voice transmission. The sensor 34 measures some magnitude significant to the operation of the machine 19, e.g. temperature, and signals the information to the monitoring station 10 to 12 at least in malfunction.
Figure 4 shows a monitoring station. The monitoring station 10 to 12 comprises a monitor 41, displaying the image conveyed by the camera 31 and information on system status presented by the graphic user interface, and working machine control means 42. The monitoring station 10 to 12 also com-prises a microphone 43 and a speaker 44 which enable voice transmission.
Let us study the deterministic data transmission protocol of the in-vention in greater detail by means of the OSI model (Open Systems Intercon nection). Deterministic refers to a predetermined data transmission delay irre spective of the load, and is preferably applied only to real-time user informa tion, not to intra-system signalling. The compression of a video image typically takes 120 to 150 ms, a few dozens of milliseconds being left for data trans-mission when the attempt is to reach a total delay of 150 to 200 ms enabling a substantially real-time remote control. Figure 5 shows a protocol stack com-prising a physical layer 51, an I/O layer 52, an MAC layer (Medium Access Control) 53, an I/O routing layer 54 and a control layer 55. Above these is an application layer 56: The physical layer 51 provides the radio interface, the ATM interface and input and output ports for data. The I/O layer 52 provides data packeting, routing of input and output data between pipes 0 to 7, and ini-tialization and control of the hardware. The MAC layer 53 provides connection set-up, automatic identification of adjacent network nodes, transmission of control data in pipe 0, error control, retransmission, etc. The term pipe refers to virtual pipes formed between the units between different input and output ports. The control layer 55 provides connection set-up between the units of the system, automatic identification of the units connected to the system, and transmission and reception of control data between the units by means of the WO 99!01943 PCT/FI98/00564 MAC. Intra-system control data (pipe 0) is routed in the units at the MAC
layer 53 and further, if needed, at the control layer 55.
A deterministic protocol is based on five features. All user data, e.g.
remote control commands, image information or voice information, is assem-5 bled into packets and routed directly at the UO routing layer to the desired in-terface (e.g. the radio interface). The terminal or the monitoring station sends the packet at predetermined intervals, e.g. 0.4 ms, and all data received from the I/O (pipes 1 to 7) after the previous packet is included in the packet.
The base station routes a packet coming from the terminal via the radio interface 10 directly at the IIO routing layer 54 to the ATM interface towards the monitoring station. The monitoring station or terminal receiving the packet disassembles it and routes the user data directly to the desired Il0 port at the I/O routing layer 54 (pipes 1 to 7). No error detection methods or retransmissions are used in user data transmission. Error correction and retransmission can, however, be arranged at the remote control desk of the monitoring station or in the machine to be controlled. The deterministic feature is also facilitated by the network preferably operating as a switched network as does ATM in which data colli-sions do not occur. The network has a very high capacity and its switches are of non-blocking type.
Pipes, which are always connected to a physical input or output port, are formed between the devices of the data transmission system at the I/O layer 52. The port can be a serial port, a video unit or another device of the data transmission system. On the basis of control information received from the upper layers, the I/O layer 52 recognizes the receiver of the data coming from the different pipes, whereby the data can be immediately forwarded with-out it having to circulate via the upper layers. Since the terminal and the monitoring station send a packet at regular intervals, the data accumulated from all I/O ports after the previous packet is assembled to the packet. The packet is transferred back to the physical layer either to the radio interface or the ATM interface. At the radio interface, an one-byte preamble, serving to identify and synchronize the packet at the receiver, is inserted at the front of the packet. At the ATM interface, a five-byte field, containing a connection identifier and additional information on connection type, is inserted at the front of the packet. The identifiers inserted by the physical layer are invisible to the IIO layer 52. The base station receives the packets from the ATM network and routes the data from different pipes in a predetermined manner. Control data (pipe 0) is transferred to the upper layers, and user data (pipes 1 to 7) is transferred directly from the I/O layer 52 to the physical layer at the radio in-terface. In this way connections are established, the IIO layer 52 is set and the system is controlled at the upper layers. The principle is that the control layer knows the entire transmission system, the MAC layer knows the adjacent nodes, and the IIO layer 52 knows the routing of the data conveyed in the dif ferent pipes. All the time, the highest layer in which user data is transferred is the IIO layer 52, ensuring the deterministic data transmission of the invention.
Although the invention has been described above with reference to the example according to the attached drawings, it is obvious that it is not re stricted thereto, but can be modified in a variety of ways within the inventive idea disclosed in the attached claims.
Claims (65)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1.~A data transmission method for enclosed environments, such as a mine, the data transmission method being used in a data transmission system comprising one or more terminals (18) and a network (20) comprising at least one base station (17), a monitoring station (10 to 12) and a backbone network (15), the data transmission system having a radio connection between the terminal (18) and the base station (17) and a bi-directional connection from the monitoring station (10 to 12) to one or more working machines (19) via the terminals (18), each of which are coupled to a working machine (19), characterized in that data between the monitoring station (10 to 12) and the terminal (18) is transmitted digitally, and one or more working machines (19) are~
controlled from the monitoring station (10 to 12) by teleoperation substantially in real time by a deterministic data transmission protocol in which the data transmission delay is within predetermined limits.
controlled from the monitoring station (10 to 12) by teleoperation substantially in real time by a deterministic data transmission protocol in which the data transmission delay is within predetermined limits.
2. A method as claimed in claim 1, characterized in that the network (20) operates on the multicasting principle, whereby transmitted messages are forwarded to more than one units connected to the network.
3. A method as claimed in claim 1, characterized in that data transmission is performed in the network (20) as in an ATM network.
4. A method as claimed in claim 3, characterized in that the ATM network (20) operates on the multicasting principle by the ATM switches (14) operating independently without control.
5. A method as claimed in claim 3, characterized in that the ATM network (20) operates on the multicasting principle so that the ATM switches (14) are under centralized control.
6. ~A method as claimed in claim 1, characterized in that transmitted messages are forwarded to all units connected to the network.
7. ~A method as claimed in claim 1, characterized in that a connection between the terminal (18) and the base station (17) is established by wireless spread spectrum signalling.
8. ~A method as claimed in claim 1, characterized in that data is transmitted in broadband, and in data transmission one or more of the following information types are transmitted substantially simultaneously: image, voice, data.
9. ~A method as claimed in claim 8, characterized in that in data transmission image, voice and data are transmitted in packets.
10. ~A method as claimed in claim 8, characterized in that each terminal (18) has a fixed data transmission band, which in data transmission is allocated to image, voice and data.
11. ~A method as claimed in claim 8, characterized in that image and/or voice information is compressed for data transmission.
12. ~A method as claimed in claim 11, characterized in that image information is dynamically compressed.
13. ~A method as claimed in claim 1, characterized in that in data transmission logical connections are established between the units by a graphic user interface.
14. ~A data transmission system to be used in enclosed environments, such as a mine, the data transmission system comprising one or more terminals (18) and a network (20) comprising at least one base station (17), a monitoring station (10 to 12) and a backbone network (15), the data transmission system having a radio connection between the base station (17) and the terminal (18) and a bi-directional connection from the monitoring station (10 to 12) to one or more terminals (18) which are coupled to a working machine (19), characterized in that the data transmission system is arranged to transmit data digitally between the monitoring station (10 to 12) and the terminal (18), and the data transmission system comprises a deterministic data transmission protocol by which one or more working machines (19) can be controlled by teleoperation substantially in real time and in which the data transmission delay is within predetermined limits.
15. A data transmission system as claimed in claim 14, characterized in that the network (20) is arranged to operate on the multicasting principle, whereby transmitted messages are forwarded to substantially all units connected to the network.
16. A data transmission system as claimed in claim 14, characterized in that the network (20) is substantially an ATM network.
17. A data transmission system as claimed in claim 16, characterized in that the ATM network (20) is arranged to operate on the multicasting principle, whereby the ATM switches (14) operate independently without separate control.
18. A data transmission system as claimed in claim 16, characterized in that the ATM network (20) is arranged to operate on the multicasting principle, whereby the ATM switches (14) can be controlled in a centralized manner.
15~
15~
19. A data transmission system as claimed in claim 14, characterized in that the data transmission system is arranged to forward transmitted messages in a restricted manner to one or more units connected to the network.
20. A data transmission system as claimed in claim 14, characterized in that the data transmission system is arranged to establish a connection between the terminal (18) and the base station (17) by wireless spread spectrum signalling.
21. A data transmission system as claimed in claim 14, characterized in that the data transmission system is arranged to perform data transmission in broadband, and that in data transmission the data transmission system is arranged to transmit substantially simultaneously one or more of the following information types: image, voice, data.
22. A data transmission system as claimed in claim 21, characterized in that in data transmission the data transmission system is arranged to transmit image, voice and data in packets.
23. A data transmission system as claimed in claim 21, characterized in that each terminal has a fixed dal:a transmission band for image and/or voice and/or data transmission.
24. A data transmission system as claimed in claim 21, characterized in that the data transmission system is arranged to compress image and/or voice information for data transmission.
25. A data transmission system as claimed in claim 24, characterized in that the data transmission system is arranged to compress image information dynamically.
26. A data transmission system as claimed in claim 14, characterized in that the data transmission system is arranged to establish logical connections between the units by a graphic user interface.
27. A data transmission method for enclosed environments, such as a mine, the data transmission method being used in a data transmission system comprising one or more terminals and a network comprising at least one base station, one or more monitoring stations and a backbone network, the data transmission system having a radio connection between a terminal and a base station and a bi-directional connection from the monitoring station to one or more working machines via respective terminals, each of which is coupled to a working machine, the method comprising digitally transmitting data between a monitoring station and one or more terminals, and one or more working machines to control said one or more working machines from the monitoring station by teleoperation substantially in real time by a deterministic data transmission protocol in which the data transmission delay is within predetermined limits.
28. A method as claimed in claim 27, further comprising operating said network on a multicasting principle, whereby transmitted messages are transmitted to more than one component of the data transmission system.
29. A method as claimed in claim 27, wherein data is transmitted on the network in an ATM network protocol.
30. A method as claimed in claim 29, further comprising operating ATM
switches independently, without control, to cause said network to operate on a multicasting principle.
switches independently, without control, to cause said network to operate on a multicasting principle.
31. A method as claimed in claim 29, further comprising ATM switches under centralized control to cause said network to operate on a multicasting principle.
32. A method as claimed in claim 27, further comprising transmitting messages to cause said messages to be forwarded to all nodes of the network.
33. A method as claimed in claim 27, further comprising establishing a connection between the terminal and the base station by wireless spread spectrum signalling.
34. A method as claimed in claim 27, further comprising transmitting image, voice and/or data information substantially simultaneously in broadband.
35. A method as claimed in claim 34, wherein said image, voice and/or data information are transmitted in packets.
36. A method as claimed in claim 34, further comprising transmitting said image, voice and/or data information in a fixed data transmission band.
37. A method as claimed in claim 34, further comprising compressing image and/or voice information for transmission.
38. A method as claimed in claim 37, further comprising dynamically compressing said image information.
39. A method as claimed in claim 27, further comprising establishing logical connections between components of the system by a graphic user interface.
18~
18~
40. ~A data transmission system to be cased in enclosed environments, such as a mine, the data transmission system comprising:
one or more terminals coupled to respective working machines;
and a network comprising:
at least one base station;
a monitoring station;
a backbone network; and a radio connection between the base station and said one or more terminals; and a bi-directional connection from the monitoring station to said one or more terminals, operably configured to transmit data digitally therebetween using a deterministic data transmission protocol by which one or more working machines can be controlled by teleoperation substantially in real time and in which the data transmission delay is within predetermined limits.
one or more terminals coupled to respective working machines;
and a network comprising:
at least one base station;
a monitoring station;
a backbone network; and a radio connection between the base station and said one or more terminals; and a bi-directional connection from the monitoring station to said one or more terminals, operably configured to transmit data digitally therebetween using a deterministic data transmission protocol by which one or more working machines can be controlled by teleoperation substantially in real time and in which the data transmission delay is within predetermined limits.
41. ~A data transmission system as claimed in claim 40, wherein the network is arranged to operate on the multicasting principle, whereby transmitted messages are transmitted to substantially all components of the system.
42. ~A data transmission system as claimed in claim 40, wherein the network includes an ATM network.
43. A data transmission system as claimed in claim 42, wherein the ATM
network includes ATM switches configured to operate independently without separate control, and to cause said ATM network to operate on the multicasting principle.
network includes ATM switches configured to operate independently without separate control, and to cause said ATM network to operate on the multicasting principle.
44. A data transmission system as claimed in claim 42, wherein the ATM
network includes ATM switches configured to be controlled in a centralized manner, and to cause said ATM network to operate on the multicasting principle.
network includes ATM switches configured to be controlled in a centralized manner, and to cause said ATM network to operate on the multicasting principle.
45. A data transmission system as claimed in claim 40, wherein the backbone network is operably configured to direct messages to different components of the system as desired.
46. A data transmission system as claimed in claim 40, wherein a connection is established between a terminal and a base station of the data transmission system by wireless spread spectrum signalling.
47. A data transmission system as claimed in claim 40, wherein said monitoring station and said one or more terminals are operably configured to perform data transmission in broadband, and to transmit substantially simultaneously one or more of the following types of information: image, voice, data.
48. A data transmission system as claimed in claim 47, wherein said monitoring station and said one or more terminals are operably configured to transmit image, void; and data information in packets.
49. A data transmission system as claimed in claim 47, wherein each terminal is operably configured to transmit image, voice and/or data information in a fixed data transmission band.
50. A data transmission system as claimed in claim 47, further comprising a compressor operably configured to compress image and/or voice information for data transmission.
51. A data transmission system as claimed in claim 50, wherein said compressor is operably configured to compress image information dynamically.
52. A data transmission system as claimed in claim 40, further comprising a graphical user interface operably configured to establish logical connections between components of the system.
53. A data transmission system to be used in enclosed environments, such as a mine, the data transmission system comprising:
one or more terminals coupled to a working machine; and a network comprising:
at least one base station;
a monitoring station;
a backbone network; and a radio connection between the base station and said one or more terminals; and means for establishing a bi-directional connection from the monitoring station to said one or more terminals, such that said monitoring station and said one or more terminals are operable to transmit data digitally therebetween using a deterministic data transmission protocol by which one or more working machines can be controlled by teleoperation substantially in real time and in which the data transmission delay is within predetermined limits.
one or more terminals coupled to a working machine; and a network comprising:
at least one base station;
a monitoring station;
a backbone network; and a radio connection between the base station and said one or more terminals; and means for establishing a bi-directional connection from the monitoring station to said one or more terminals, such that said monitoring station and said one or more terminals are operable to transmit data digitally therebetween using a deterministic data transmission protocol by which one or more working machines can be controlled by teleoperation substantially in real time and in which the data transmission delay is within predetermined limits.
54. A data transmission system as claimed in claim 53, wherein the network is includes means for transmitting messages to substantially all components of the system.
55. A data transmission system as claimed in claim 53, wherein the network includes an ATM network.
56. A data transmission system as claimed in claim 55, wherein the ATM
network includes ATM switches configured to operate independently without separate control, and to cause said ATM network to operate on the multicasting principle.
network includes ATM switches configured to operate independently without separate control, and to cause said ATM network to operate on the multicasting principle.
57. A data transmission system as claimed in claim 55, wherein the ATM
network includes means for controlling ATM switches in a centralized manner, to cause said ATM network to operate on the multicasting principle.
network includes means for controlling ATM switches in a centralized manner, to cause said ATM network to operate on the multicasting principle.
58. A data transmission system as claimed in claim 53, wherein the backbone network includes means for directing messages to different components of the system as desired.
59. A data transmission system as claimed in claim 53, further including means for establishing a connection between the terminal and the base station by wireless spread spectrum signalling.
60. A data transmission system as claimed in claim 53, wherein said monitoring station and said one or more terminals include means for broadband transmission of data including substantially simultaneous transmission of one or more of the following types of information:
image, voice, data.
image, voice, data.
61. A data transmission system as claimed in claim 60, wherein said monitoring station and said one or more terminals include means for transmitting image, voice and data, in packets.
62. A data transmission system as claimed in claim 60, wherein each terminal includes means for transmitting image, voice and/or data in a fixed data transmission band.
63. A data transmission system as claimed in claim 60, further comprising compressing means for compressing image and/or voice for data transmission.
64. A data transmission system as claimed in claim 63, wherein said compressing means is operably configured to compress image information dynamically.
65. A data transmission system as claimed in claim 53, further comprising means for establishing logical connections between components of the system, said means including a graphical user interface.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| FI972868A FI113318B (en) | 1997-07-04 | 1997-07-04 | Data communication procedure and data communication system |
| FI972868 | 1997-07-04 | ||
| PCT/FI1998/000564 WO1999001943A2 (en) | 1997-07-04 | 1998-07-01 | Data transmission method and data transmission system |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2294792A1 CA2294792A1 (en) | 1999-01-14 |
| CA2294792C true CA2294792C (en) | 2005-11-15 |
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ID=8549196
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002294792A Expired - Fee Related CA2294792C (en) | 1997-07-04 | 1998-07-01 | Data transmission method and data transmission system |
Country Status (8)
| Country | Link |
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| AR (1) | AR016763A1 (en) |
| AU (1) | AU735206B2 (en) |
| CA (1) | CA2294792C (en) |
| FI (1) | FI113318B (en) |
| PE (1) | PE101799A1 (en) |
| SE (1) | SE519845C2 (en) |
| WO (1) | WO1999001943A2 (en) |
| ZA (1) | ZA985779B (en) |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FI118112B (en) * | 2004-10-22 | 2007-06-29 | Sandvik Tamrock Oy | Arranging mobile mining device communications |
| CN102635396A (en) * | 2012-03-30 | 2012-08-15 | 长治清华机械厂 | Mining rescue capsule environment detector |
| CN103714682B (en) * | 2014-01-02 | 2015-07-08 | 山东中科纳米管材有限公司 | Information transmission switching method and system applied to coal mine |
| CN109695477A (en) * | 2019-02-28 | 2019-04-30 | 安徽腾策网络科技有限公司 | Underground safety monitoring system and its working method |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2288300A (en) * | 1994-04-05 | 1995-10-11 | Christopher Robert Turner | Video surveillance system using spread spectrum radio communication |
| AUPM593694A0 (en) * | 1994-05-27 | 1994-06-23 | Curtin University Of Technology | Underground microcellular communications network |
| US5697067A (en) * | 1994-09-15 | 1997-12-09 | Mine Radio Systems Inc. | Communication system utilizing radiating transmission line |
| IT1271321B (en) * | 1994-12-23 | 1997-05-27 | Italtel Spa | DEVICE AND METHOD FOR THE MANAGEMENT OF MULTICAST CALLS FOR DISTRIBUTIVE AUDIO AND VIDEO SERVICES IN A LOCAL ATM TYPE NODE |
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1997
- 1997-07-04 FI FI972868A patent/FI113318B/en not_active IP Right Cessation
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1998
- 1998-06-26 PE PE1998000566A patent/PE101799A1/en not_active Application Discontinuation
- 1998-07-01 CA CA002294792A patent/CA2294792C/en not_active Expired - Fee Related
- 1998-07-01 AU AU82174/98A patent/AU735206B2/en not_active Ceased
- 1998-07-01 WO PCT/FI1998/000564 patent/WO1999001943A2/en active IP Right Grant
- 1998-07-01 ZA ZA985779A patent/ZA985779B/en unknown
- 1998-07-03 AR ARP980103258A patent/AR016763A1/en unknown
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2000
- 2000-01-03 SE SE0000010A patent/SE519845C2/en not_active IP Right Cessation
Also Published As
| Publication number | Publication date |
|---|---|
| SE0000010L (en) | 2000-01-03 |
| AR016763A1 (en) | 2001-08-01 |
| WO1999001943A2 (en) | 1999-01-14 |
| SE0000010D0 (en) | 2000-01-03 |
| CA2294792A1 (en) | 1999-01-14 |
| SE519845C2 (en) | 2003-04-15 |
| AU8217498A (en) | 1999-01-25 |
| ZA985779B (en) | 1999-01-14 |
| WO1999001943A3 (en) | 1999-03-25 |
| AU735206B2 (en) | 2001-07-05 |
| FI972868A0 (en) | 1997-07-04 |
| FI113318B (en) | 2004-03-31 |
| FI972868A (en) | 1999-01-05 |
| WO1999001943A8 (en) | 1999-05-14 |
| PE101799A1 (en) | 1999-10-18 |
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