WO1998043392A1 - Procede et dispositif pour interconnecter des reseaux de commande via une liaison a multiplexage par repartition dans le temps - Google Patents

Procede et dispositif pour interconnecter des reseaux de commande via une liaison a multiplexage par repartition dans le temps Download PDF

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Publication number
WO1998043392A1
WO1998043392A1 PCT/CA1998/000283 CA9800283W WO9843392A1 WO 1998043392 A1 WO1998043392 A1 WO 1998043392A1 CA 9800283 W CA9800283 W CA 9800283W WO 9843392 A1 WO9843392 A1 WO 9843392A1
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WIPO (PCT)
Prior art keywords
control
tdm
networks
messages
data
Prior art date
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PCT/CA1998/000283
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English (en)
Inventor
Tho Le-Ngoc
André Martin
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Primetech Electronics Inc.
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Publication date
Application filed by Primetech Electronics Inc. filed Critical Primetech Electronics Inc.
Priority to AU68175/98A priority Critical patent/AU6817598A/en
Publication of WO1998043392A1 publication Critical patent/WO1998043392A1/fr

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Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L12/00—Data switching networks
    • H04L12/28—Data switching networks characterised by path configuration, e.g. LAN [Local Area Networks] or WAN [Wide Area Networks]
    • H04L12/2803—Home automation networks
    • H04L12/283—Processing of data at an internetworking point of a home automation network
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L12/00—Data switching networks
    • H04L12/28—Data switching networks characterised by path configuration, e.g. LAN [Local Area Networks] or WAN [Wide Area Networks]
    • H04L12/2803—Home automation networks
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L12/00—Data switching networks
    • H04L12/28—Data switching networks characterised by path configuration, e.g. LAN [Local Area Networks] or WAN [Wide Area Networks]
    • H04L12/2803—Home automation networks
    • H04L12/2838—Distribution of signals within a home automation network, e.g. involving splitting/multiplexing signals to/from different paths
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L12/00—Data switching networks
    • H04L12/28—Data switching networks characterised by path configuration, e.g. LAN [Local Area Networks] or WAN [Wide Area Networks]
    • H04L12/46—Interconnection of networks
    • H04L12/4604—LAN interconnection over a backbone network, e.g. Internet, Frame Relay
    • H04L12/462—LAN interconnection over a bridge based backbone
    • H04L12/4625—Single bridge functionality, e.g. connection of two networks over a single bridge
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L12/00—Data switching networks
    • H04L12/64—Hybrid switching systems
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L12/00—Data switching networks
    • H04L12/66—Arrangements for connecting between networks having differing types of switching systems, e.g. gateways
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L12/00—Data switching networks
    • H04L12/28—Data switching networks characterised by path configuration, e.g. LAN [Local Area Networks] or WAN [Wide Area Networks]
    • H04L12/2803—Home automation networks
    • H04L2012/284—Home automation networks characterised by the type of medium used
    • H04L2012/2841—Wireless
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L12/00—Data switching networks
    • H04L12/28—Data switching networks characterised by path configuration, e.g. LAN [Local Area Networks] or WAN [Wide Area Networks]
    • H04L12/2803—Home automation networks
    • H04L2012/284—Home automation networks characterised by the type of medium used
    • H04L2012/2845—Telephone line

Definitions

  • the present invention relates to a method and apparatus for interconnecting control networks via a time division multiplexing (TDM) link.
  • TDM time division multiplexing
  • trainline communications systems were based on a bus of several parallel wires extending from car to car across the trainline. Each wire was dedicated to a specific task, such as throttle, braking, door open control, intercom, etc. As rail cars and remote locomotives were improved by adding more control and diagnostic features, more wires were added to the bus. As the need for more wires increased, the electrical inter-car couplers also grew more complex, expensive and less reliable. To reduce the number of wires passing through the train cars, a technique new to trainlines was applied: Time Division Multiplexing. This technique was widely implemented in telephone networks, allowing a large number of relatively low bandwidth signals to be combined and to share a single high bandwidth channel.
  • trainline multiplexer TMX
  • TMX trainline multiplexer
  • each system manufacturer had its own protocol for communicating between its own system devices in other cars. This meant that for different system or manufacturer, there was potentially a different communications protocol being used. Intercommunication between various systems was difficult if not impossible.
  • Distributed control systems based on high-performance, low-cost microprocessor/microcontrollers have found a growing number of applications in freight train, passenger train and subway systems, as well as applications in building, home and factory automation, automobiles and security systems.
  • Such a distributed control and monitoring system comprises a number of local control nodes, each using a special-purpose microprocessor or microcontroller connected to the various sensing and operating devices on some particular controlled equipment (propulsion, brake, door opening, lighting, air conditioning, visual annunciator, intercom, etc.).
  • the local control node is located close to the controlled equipment and automates the operation of that equipment by inputting data from the sensing devices and outputting the appropriate control signals to the operating devices.
  • the exchange of input and output data between the control node and the devices on the controlled machinery is normally accomplished by direct connections between ports on the control node and each device. Interconnection between control nodes supports the exchange of information between them over a train monitoring and or control network in order to provide a global control system.
  • Such control networking can be provided by known networks such as the communication network disclosed in US 5,537,549 issued to Gee et al.
  • a networking system is usually based on a serial link in order to simplify the connectivity between nodes attached to the network.
  • the train monitoring and or control networking standards such as the LonWorks® network and corresponding LonTalk® protocol also make use of serial link for the same reason.
  • Time Division Multiplexing has been used in digital trainline communications to combine several electrical signals in a single multiplexed signal able to feed a single digital radio channel for permitting communications between adjacent cars of a multi-car vehicle disclosed in US 5,351,919 issued to Martin.
  • the TDM link formed the basic structure in the development of standards established for digital networks, transmission systems and multiplexing equipment.
  • Internetworking generally means the connection of two or more networks to allow an exchange of information between the various networks and within the individual networks arranged in a variety of formats.
  • the OSI Reference Model calls a device to interconnect two systems not connected directly to each other a relay. If the relay shares a common layer n protocol with other systems, but does not participate in a layer n+1 protocol, it is a layer n relay. Repeater is the physical layer relay. Bridge is the datalink layer relay. Router is the network layer relay. Gateway is any relay at layer higher than network layer. Both bridges and routers can make forwarding or routing decisions based on information in the packet headers. A bridge differs fundamentally from a router. A bridge typically relays Media Access Control (MAC) layer (or data link layer which is layer two in the OSI model) frames and decisions are made based on information in the frame header. A router relays network layer (layer three in the OSI model) datagrams and decisions are based on information in the network layer header.
  • MAC Media Access Control
  • a router relays network layer (layer three in the OSI model) datagrams and decisions are based on information in the network layer header.
  • gateway is often used for any relay operating at the datalink layer, network layer, or any higher layer. In general, gateways are mostly used for interconnecting heterogeneous networks.
  • each half normally operates between the protocols used in its network and an intermediate protocol.
  • intermediate protocol There are significant advantages to a standard intermediate protocol. Without a common intermediate representation, designing relays between n different networks could require a distinct mapping between each network and each of the (n-1) others, or n(n-l) mappings.
  • Patent 5,490,252 issued to Macera et al.
  • an internetworking relay apparatus for exchanging control messages between control networks over a TDM link transporting both control data from said control networks and communications data from communications devices, said relay apparatus connecting one of the control networks to the TDM link.
  • the apparatus comprises means for receiving control messages in an original control message format from one of the control networks and means for converting the control messages received into a corresponding control data stream when addressed to a control node on another one of said control networks.
  • TDM channellization means for transferring to the TDM link the control data stream for transmission to a corresponding internetworking apparatus connected to the other control network, and means for receiving control data streams from the TDM link sent from other ones of said control networks.
  • the apparatus further comprises means for converting ones of the control data streams which are addressed to a control node of said one control network into corresponding control messages using the original control message format, and means for transmitting the corresponding control messages to said one control network.
  • the TDM channellization means comprise first control means connected to the control data streams receiving means, said first control means detecting when the TDM link is available for control message transmission to produce a corresponding first control signal according to a predetermined access allocation, said first control means further detecting a beginning TDM frame slot to produce a corresponding second control signal according to a reference synchronization.
  • the TDM channellization means further comprise first data buffer means coupled to the control messages converting means and connected to the first control means for temporarily storing the control data stream whenever receiving the first control signal, and first serial interface means connected to the TDM link and the first control means, the first serial interface means being coupled to the first data buffer means to transmit the control data stream to a sufficient number of allocated TDM frame time-slots whenever receiving the second control signal.
  • control data streams receiving means comprise second serial interface means connected to the TDM link for receiving the control data streams sent from other ones of the control networks in the allocated TDM frame time-slots, second data buffer means coupled to the second serial interface and to the control data streams converting means, said second data buffer means temporarily storing the control data streams, and second control means connected to the second serial interface means and the second data buffer means for controlling transfer of the control data stream to the data streams converting means.
  • an internetworking system for exchanging control messages between a plurality of control networks over a TDM link transporting both control data from said control networks and communications data from communications devices, said system comprising a plurality of relays each connecting each said control networks to the TDM link.
  • Each relay comprises means for receiving control messages in an original control message format from one of the control networks and means for converting the control messages received into a corresponding control data stream when addressed to a control node on another one of said control networks.
  • Each relay further comprises TDM channellization means for transferring to the TDM Unk the control data stream for transmission to a corresponding relay connected to the other control network, and means for receiving control data streams from the TDM link sent from other ones of the control networks.
  • a method for exchanging control messages between control networks over a TDM link transporting both control data from the control networks and communications data from communications devices comprises steps of: a) receiving control messages in an original control message format from one of the control networks; b) converting the control messages received into a corresponding control data stream when addressed to a control node on another one of the control networks; c) transferring to the TDM link the control data stream for transmission to the other control network; d) receiving control data streams from the TDM link sent from other ones of said control networks; e) converting ones of said control data streams which are addressed to a control node of said one control network into corresponding control messages using the original control message format; and f) transmitting the corresponding control messages to said one control network.
  • Fig. 1 illustrates the overall structure of an integrated communications control networks system based on a TDM link using a relay in accordance with the present invention.
  • Fig. 2 depicts the logical configuration of internetworking between a control network and the TDM network, showing the layered structure of a relay in accordance with the present invention.
  • Fig. 3 is a block diagram of a first preferred embodiment of a relay according to the present invention, showing how the relay can be implemented using one single Neuron® Chip connected with an interface module.
  • Fig. 4 is a block diagram of a second preferred embodiment of a relay according to the invention, showing an implementation structure using two Neuron® Chips with adapted design of the interface module.
  • Fig. 5 is a block diagram of a third preferred embodiment of a relay according to the invention, showing an implementation of the relay with multiplexing capability.
  • Fig. 6a illustrates a prior art system configuration to interconnect communications and control networked between buildings.
  • Figs. 6b-6d illustrates various application examples of the present invention to interconnect communications and control networks between buildings.
  • Fig. 7a illustrates a prior art system configuration to interconnect communications and train monitoring and or control networks between train cars.
  • Fig. 7b illustrates a prior art application example to interconnect communications, train monitoring and or control networks between adjacent cars of a multi-car vehicle using two wireless links.
  • Figs. 7c, 7d, 7e and 7f illustrate an application example of the present invention to interconnect communications, train monitoring and or control networks between adjacent cars of a multi-car vehicle using a single wireline link.
  • the invention is directed to the scheme to transport a control network over a Time Division Multiplexing (TDM) link in order to offer an integrated control communications network.
  • TDM Time Division Multiplexing
  • CSMA Carrier-Sense Multiple-Access
  • LonWorks® networks on a group of assigned channel time-slots of a TDM frame structures, methods to preserve the LonTalk® Protocol, and the schemes to encapsulate the LonTalk® control messages, to allow dynamic access allocation and to share the TDM channel time-slots.
  • Other channel time-slots of the TDM link can be assigned to cany voice, video communications.
  • the relay according to the present invention provides internetworking using a TDM link to support an integrated network including control networks, digital voice and video communications so that the interface to international standard digital networks is possible.
  • a TDM relay or gateway is introduced.
  • the functions of the TDM gateway are: a) to encapsulate the control messages; b) to organize the encapsulated control messages into suitable data streams, and to transfer them over TDM channel time- slots; and c) to provide dynamic access allocation and de-allocation mechanism by sending special codes indicating the assignment of the channel time-slots to another control node.
  • the TDM gateway To transfer information from the TDM channel time-slots back to the control network or control node, the TDM gateway performs the following functions: d) recognizing the assignment of the TDM slots for transmission; e) receiving the encapsulated control messages; and f) reconverting them back to their original LonTalk® control messages.
  • Interfacing the TDM gateway to the LonWorks® network or LonWorks® control node follows the procedures and functions defined by the LonTalk® protocol.
  • the TDM gateway provides all the functions required by the LonTalk® protocol, including three layers: physical, datalink, and network. Interface between the TDM gateway and the TDM link requires a new set of design techniques, approaches and implementation procedures. Therefore, the present invention uses concepts, approaches, structures and techniques to design the interfacing functions between the TDM gateway and the TDM link, including associated physical, datalink, and network layers. Furthermore, the present invention also provides the internetworking functions required to interconnect the above two mentioned sets of interfacing functions within the TDM gateway.
  • the present invention provides a TDM gateway which is a high performance, high availability internetworking relay.
  • the TDM gateway can be used to interconnect a plurality of individual control networks and/or control nodes of a distributed control network such as many or all of the control networks operated by a large corporation whose operations could be located in different geographic areas, via the local, national or international TDM network(s).
  • the TDM gateway can utilize an architecture based on the standard TDM hierarchy for Pulse-Code Modulation (PCM) multiplex equipment defined by the International Telecommunication Union (ITU) for digital networks transmission systems and multiplexing equipment in order to provide an integrated control and communications network.
  • PCM Pulse-Code Modulation
  • ITU International Telecommunication Union
  • control networks 11 use the LonTalk® protocol to support the exchanges of control messages between control nodes 15.
  • control messages can be sent using a CSMA scheme.
  • the idle period between control messages comprises a fixed ⁇ l time, and ⁇ 2 slots. If more than one nodes transmit their packets at the same time, collision occurs. The involved nodes can detect collision and re-transmit their packets after a randomly chosen time interval. Priority feature is also available for transmission without collision.
  • the TDM Gateway 10 may interconnect directly control nodes 12, or various control nodes 15 via their control networks 11, to the TDM link 13.
  • the TDM link 13 also provides channels for communications device 14.
  • the TDM link 13 comprises several time-slot channels.
  • the frame structure of a primary PCM multiplex equipment operating at 1.544Mb/s (or Tl TDM link) has 24 channel time-slots, each can accommodate one 64kb/s circuit.
  • the frame structure of a primary PCM multiplex equipment operating at 2.048Mb/ s (or El TDM link) which has 32 channel time- slots: two reserved for framing and signaling and the remaining 30 for traffic, each also can accommodate one 64kb/s circuit.
  • the TDM link capacity is time-shared between various circuits to support both communications devices or control networks.
  • the 30 traffic time-slots of a 2.048Mb/s El TDM link can be shared as follows. Two time-slots with a capacity of 128kb/s are dedicated for interconnecting control networks, and the remaining 28 time-slots are used to carry data, voice and/or video circuits.
  • Fig. 1 shows the interconnection of various local control networks 11 and communications devices 14 in one location to the single TDM link 13.
  • the TDM link 13 is connected to another location or to a public network.
  • Some benefits of the invention are high-performance, transparent interworking, a unified architecture which provides seamless internetworking based on a well established, widely used TDM standard, and a comprehensive manageability and testability.
  • the above examples use primary PCM multiplex equipment to illustrate the system operation.
  • the present invention can directly applies other second-order and higher-order multiplex equipment TDM standards based on 64kb/s channellization.
  • the above examples use the basic time- division multiplexing scheme. Therefore, it is also applicable to other TDM links, such as basic 2B+D ISDN (Integrated Services Digital Networks), primary ISDN and broadband ISDN.
  • control network 11 is assumed to be based on the LonTalk® protocol defined in the LonTalk Protocol Specification, Version 0.1, Revision Dec. 12, 1996, Echelon Corp., which is incorporated herein by reference, and is known as a LonWorks® network, each control node 15 being a LonWorks® node.
  • the TDM gateway 10 accesses the control network 11 in a same manner as a control node 15, using the LonTalk® protocol defined in the LonTalk Protocol Specification.
  • the TDM Gateway 10 is interfaced to the TDM link 13 in a similar manner as a communications device 14 using the standard TDM specifications defined in the Digital Networks Transmission Systems and Multiplexing Equipment, Recommendations G.701- G.941, International Telecommunication Union, Yellow Book, Vol. HI, Fascicle HI.3, Geneva, 1981, which is incorporated herein by reference.
  • the TDM Gateway 10 serves as an application node so that the LonWorks® network 11 and the TDM link 13 are totally separate. The installation of the TDM link 13 can ignore the LonWorks® networks 11 and vise versa. Therefore, the LonWorks® networks 11 and the TDM link 13 can be installed at different times by different tools. Referring to Fig.
  • the TDM gateway 20 provides the complete function stacks 22 of the physical layer, datalink layer including the multiple-access control (MAC) sub-layer, and network layer required to support the control protocol for communications with the control network 21.
  • the TDM gateway 20* provides complete function stacks 24 of the physical layer, datalink layer including the multiple-access control (MAC) sub-layer, and network layer required to support the control protocol for communications with the control network 25.
  • the TDM gateway 20 and 20' each provides new function stacks 23, equivalent to three layers: physical, datalink, and network for communications via the TDM link 13.
  • the TDM gateways 20 and 20' each acts as a half-relay or half- gateway.
  • the function stacks 23 is designed for the common intermediate protocol or format operating over TDM time-slots.
  • the introduction of the TDM Gateways 20 and 20' allows the internetworking between various control networks 21 and 25 via a common TDM network.
  • the control networks 21 and 25 are based on the LonTalk® protocol
  • the control nodes 15 shown in Fig. 1 can communicate to each other via the TDM link 13 using the LonTalk® protocol exactly in the same manner as their communications via the LonWorks® networks 21 and 25 shown in Fig. 2
  • the TDM gateways 20 and 20' provide a transparent connection with respect to the LonTalk® protocol.
  • New function stacks for three layers Referring to Fig. 2, the new function stacks 23 covers three layers: physical, datalink (including the MAC sub-layer), and network.
  • the physical layer comprises the bit and frame synchronization functions, the serial transmission and reception required to accessing the allocated time-slots of the TDM bit stream according to the specifications defined in the Digital Networks Transmission Systems and Multiplexing Equipment, Recommendations G.701-G.941.
  • the 2.048Mb/s standard is used to implement the TDM link 13 in FIG. 1.
  • the 2.048Mb/s TDM structure is based on a frame unit or time-slot of 125 micro-seconds. Each frame
  • Each time-slot can accommodate 8 bits. Normally, TSO is used to carry the framing codeword that denotes the beginning of the frame. Time-slot TS16 is normally reserved for signaling and can carry the multiframe codeword. The other 30 time-slots are used to carry traffic. Each time-slot has 8 bits per frame unit of 125 microseconds. Therefore, each traffic time-slot can accommodate a channel of 64kb/s. Accordingly, to support a service that requires a capacity of Nx64kb/s over a 2.048Mb/s link we need to allocate N time-slots. For example, referring to Fig.
  • time-slots say TS1 and TS2.
  • the TDM gateways 10 in Fig. 1 all transmit and receive information in the time- slots TS1 and TS2.
  • the physical layer of the new function stacks 23 in Fig. 2 establishes both the bit and frame synchronization, identifies the time-slots TS1 and TS2, and supports the serial transmission and reception of data in these two time-slots.
  • control messages separated by idle periods as follows:
  • a control message has the following sequence: PREAMBLE, SYNC, DATA, CRC, CODE VIOLATION.
  • each control message is segmented into 7-bit words.
  • Each time-slot, TSl or TS2 has 8 bits: B0, Bl, ...., B7 per frame unit of 125 microseconds.
  • the access to the TDM time-slots is collision-free.
  • the allocation code message contains the ID (identification) of the assigned TDM gateway 10.
  • the assigned TDM gateway 10 can send its control messages. If it does not have any message to send then the master will allocate the TDM slots to another.
  • the master gateway can allocate TDM slots to TDM gateways 10 in a round-robin manner or in a certain priority basis.
  • the allocation code message is transmitted only during an idle period and can have the same format.
  • bit B0 of the 8 bits in the allocated time-slots (e.g., TSl and TS2) is 0.
  • the allocation code message can have the following format: ALLOCATION CODE, ID, PARITY where ALLOCATION CODE is a 7-bit code,
  • ID is the identification of the assigned TDM gateway
  • PARITY is the parity bits of a error-correction code selected to improve the detection performance of the allocation code message.
  • the activity over the allocated time-slots TSl and TS2 is as follows:
  • the communications between these two TDM gateways over the TDM time- slots are of the point-to-point type.
  • one TDM gateway transmits to the other and vice versa. Since there is only one transmitting or receiving TDM Gateway on each side, multiple-access is not required. Consequently, the monitoring and generation of the allocation code message are not needed.
  • the network layer supports the transfer of control messages from the control network side to the TDM link side, or vise versa.
  • Network layer functions include the scanning, recognizing and filtering of the destination address contained in the preamble or header of the control messages.
  • the TDM gateway 10 is implemented by using one Neuron®
  • a transceiver 31 provides the input and output interfaces to the control network link 38.
  • the choice of the transceiver depends on the medium used for the control network link 38. Examples of transceiver designs are given in the LonWorks® Technology Device Data Manual, DL159/D, Motorola, October, 1995, which is incorporated herein by reference.
  • the interface between the transceiver 31 and the Neuron® Chip 32 is done using serial ports.
  • the Neuron® Chip 32 is connected to the buffer 33 via its parallel port.
  • Software functions implemented in the Neuron® Chip 32 include: a) the datalink and network layers for the LonTalk® protocol as identified in the function stacks 22 in Fig.
  • the Neuron® Chip 32 When the Neuron® Chip 32 has control messages to be transfer to the TDM link 13, it first checks an handshaking signal input to its parallel port. Note that this handshaking signal is produced by a buffer 33 provided on an interface module 37 for the single-Neuron® Chip 32 as part of the gateway 10. If the handshaking signal indicates that the TDM link 13 is currently available to this TDM gateway to access, the Neuron® Chip 32 transfers the control messages to the buffer 33 byte by byte. Under the control of a synchronization and control unit 34, data are transferred from the buffer 33 to a serial interface 36.
  • data can also be forward-error control (FEC) encoded by an FEC encoder/decoder (codec) 35 before being loaded to the serial interface 36.
  • FEC forward-error control
  • codec codec
  • the serial interface 36 on the transmit side, contains a parallel-in serial-out register. In each TDM frame time interval, it receives a block of data from the FEC Codec 35 or directly from Buffer 33 as discussed above. Subsequently, this data block will be serially transmitted as part of a data stream into the allocated time-slots of the TDM link 13 by the serial interface 36 under the timing control of the synchronization and control unit 34. If the optional FEC codec 35 is not used, the serial data transmitted over the allocated TDM time-slots preserves the format of the control messages.
  • each control message is simply fragmented into a number of segments, each being encoded into a codeword of a selected error correction code.
  • the FEC codec 35 is made as an option as previously discussed. This optional FEC codec 35 is applied with an appropriate FEC code selected to improve the transmission performance if necessary.
  • the serial interface 36 also receives data stream in the allocated time-slots of the TDM link 13. Data is then transferred from the serial interface 36 to the buffer 33 and finally to the Neuron® Chip 32. If data is FEC encoded, it is FEC decoded by the FEC codec 35 before being transferred to the buffer 33.
  • the software of the Neuron® Chip 32 performs the network layer functions to scan, recognize and filter the destination address in the header of the control messages received from the TDM link 13. Only the control messages destined to the control network link 38 are further processed and transferred, others being discarded.
  • the optional FEC codec 35 takes care of part of the datalink layer function.
  • the synchronization and control Unit 34 provides TDM synchronization, multiple- access control, and timing and control.
  • the bit synchronization must be done first.
  • the receive and transmit clock signals of all the TDM gateways 10 connected to the same TDM link 13 in Fig. 1 are synchronized to a designated reference transmit clock of one of the TDM gateways selected as part of the network configuration.
  • the synchronization and control Unit 34 searches for the frame codeword that denotes the beginning of the TDM frame. Since the time-slots in a TDM frame have the fixed lengths, the positions of the time-slots allocated to transport the control messages can be derived from the position of the detected frame codeword, and based on the synchronized clock signal.
  • the TDM time-slots allocated to transport the control messages are shared by the TDM gateways 10 connected to the same TDM link 13 in Fig. 1. On the receive side, all TDM gateways 10 simply transfer data contained in the allocated time-slots to their respective buffer 33 in Fig.
  • the synchronization and control unit 34 in Fig. 3 monitors the received data at the input to buffer 33 and searches for the allocation code message mentioned in Section 3. Since the allocation code message is not part of the protocol used by the control network, it will be removed by the synchronization and control unit 34 and not transferred to the Neuron® Chip 32. If the allocation code message indicates its identification number then the TDM gateway has its access right. In this case, the synchronization and control unit 34 informs the Neuron® Chip 32 so that the latter can send its data.
  • the Neuron® Chip 32 has data to send, it does so; if not, or at the end of the data transmission, it informs the synchronization and control Unit 34 to release its access to the allocated time-slots (i.e. setting the bit BO of the time- slots to 0).
  • the synchronization and control unit 34 may also need to generate the allocation code message. If the chain allocation scheme is used, the synchronization and control unit 34 will send an allocation code message indicating the ID of the next TDM gateway that will have the access right. If the fixed allocation scheme is used, the master TDM gateway will take care of the allocation.
  • the buffer 33 in Fig. 3 is organized as a two-port memory block. Data transfer between the buffer 33 and Neuron® Chip 32 is clocked by the Neuron® Chip 32. Data transfer between the buffer 33 and FEC codec 35 or serial interface 36 is clocked by the synchronization and control unit 34. In other words, the synchronization and control unit 34 generates the various timing and control signals required to clock the buffer 33, FEC codec 35 and serial interface 36.
  • Dual-Neuron® Chip Structure Turning now to Fig.
  • the transceiver 41 is a LonWorks® transceiver interfaced to the Neuron® Chip 42 via its serial ports.
  • the Neuron® Chips 42 and 49 communicate to each other via their parallel ports.
  • the transceiver 41, Neuron® Chips 42 and 49 form the structure of a regular LonWorks®
  • the transceiver 50 as part of the interface module 37 of the Dual-Neuron® Chip implementation structure, is interfaced to the Neuron® Chip 49 via its serial ports. Under the control of the synchronization and control unit 44, the transceiver 50 transfers serial data from the Neuron® Chip 49 to the buffer 33 and vice versa.
  • the serial data transfer protocol for Special-Purpose Mode Physical I/O described in pages 22-23 of the above cited LonTalk Protocol Specification (Draft) and Neuron® Chip Special-Purpose Mode Transceiver Interface Specification, LonWorks® Engineering Bulletin, Echelon, October 1991, can be used, the latter specification being also incorporated herein by reference.
  • the Neuron® Chip 49 When the Neuron® Chip 49 has control messages to be transfer to the TDM link 13, it will first check the status byte on the serial port received from the transceiver 50. This status byte is generated by the synchronization and control unit 34 to indicate whether the time- slots are currently available to this TDM gateway to access. If the status byte indicates a busy situation, the Neuron® Chip 49 holds the control messages waiting for its turn. Otherwise, it transfers the control messages to the buffer 33 byte by byte. Under the control of the synchronization and control unit 34, data are transferred from the buffer 33 to the serial interface 36. As an option, data can also be forward-error control (FEC) encoded by the FEC codec 45 before being loaded to the serial interface 36.
  • FEC forward-error control
  • serial interface 36 under the timing control of the synchronization and control unit 44.
  • the serial interface 36 also receives data from the allocated time-slots of the
  • Data is then transferred from the serial interface 36 to the buffer 33 and finally to the Neuron® Chip 49. If data is FEC encoded, it is FEC decoded by the FEC codec 35 before being transferred to the buffer 33.
  • the software of the Neuron® Chips 49 and 42 perform the network layer functions to scan, recognize and filter the destination address in the header of the control messages received from the TDM link 13. Only the control messages destined to the control network link 38 are further processed and transferred, others being discarded. Such software is similar to that of the regular LonWorks® Router.
  • the optional FEC codec 35 takes care of part of the datalink layer function.
  • the synchronization and control unit 34 provides: a) the timing, bit, frame, and time-slot synchronization required to support the physical layer functions of the TDM link; b) the MAC functions to access the allocated time-slots and to provide the status information to the Neuron® Chips 49 ; and c) the timing and control signals required to operate the Buffer 33, FEC codec 35, and serial interface 36. It is pointed out that the time-slots allocated to transport the control networks over the TDM link 13 can be accessed by various TDM gateways using one of the three possible schemes discussed in Section 3 above regarding new function stacks for the three layers above.
  • the allocation code message is monitored and generated by the synchronization and control unit 34 in a similar manner as previously discussed in Section 4.1 above.
  • each TDM time-slot has a capacity of 64kb/s.
  • FEC forward error-correction
  • a control message includes the following sequence: Preamble (Bit and Byte Sync's), Data, Cyclic redundancy Code (CRC), Code violation.
  • the Data portion contains source and destination addresses, control information and other attributes.
  • the complete LonTalk® formats for control messages are described in the above cited LonTalk Protocol Specification (Draft). For simplicity and transparency, the control message format is preserved in the transmission over the TDM time-slots. An example of the transparent transmission of the control messages was discussed in Section 3.
  • the TDM gateways access the allocated TDM time-slots on a collision-free basis. A TDM gateway only sends its control messages in the shared time-slots when it obtains its assignment. The TDM gateway releases the time-slots after it has finished its transmission.
  • Each TDM Gateway has its own identification (ID).
  • ID the TDM Gateway with the lowest valued ID will have the first right to access the TDM slots.
  • Such process is repeated until the TDM gateway with the highest valued ID gets its access right.
  • it then sends an allocation code message indicating the lowest valued ID, the chain being then repeated.
  • TDM gateway #n is currently transmitting its control messages. At the end of its transmission, it sends a release code message and subsequently an allocation code message indicating that TDM Gateway #(n+l) has the access right.
  • TDM gateway #n then monitors the channel and waits for a time interval called waiting window.
  • the duration of this waiting window is programmable by the user and is set by software as a system configuration parameter.
  • the TDM gateway #(n+l) is expected to respond within this waiting window. There are three following possibilities: 1) If the TDM gateway #(n+l) has control messages to send, it first sends an acknowledge Code message containing its ID and then start the transmission of the control messages, the acknowledge code message being simply the echo of the allocation code message;
  • TDM gateway #(n+l) If the TDM gateway #(n+l) does not have any control message to send at this moment, it sends an Allocation Code containing the ID of the TDM Gateway #(n+2);
  • TDM gateway #(n+l) If the TDM gateway #(n+l) is not operational then it cannot response. Upon the expiration of the Waiting Window (i.e., time-out situation), The TDM gateway #n sends another Allocation Code but containing the ID of the TDM gateway #(n+2). In other words, the channel is now assigned to the TDM gateway #(n+2).
  • the TDM gateway can also be designed as part of a TDM multiplex equipment to provide an additional support on communications devices.
  • the interface module 37 is identical to that described in Section 4.1 above with reference to Fig. 3 .
  • the synchronization and control unit 34 of the module 37 already includes functions necessary to perform TDM bit, time-slot, and frame synchronization as well as associated timing and control signals. These functions and associated signals can also be used to operates a TDM multiplexer 52.
  • the TDM gateway 10 can support connections for communications devices which operate on the basis of 64kb/s channellization.
  • Such communications devices include 64kb/s PCM voice circuits, Nx64kb/s digital video connections (e.g., 384kb/s) and other voice, video and data circuits operating at rate of multiples of 64kb/s.
  • the interface module 37 based on that illustrated on Fig. 3 is given for illustration. It can also be based on that illustrated on Fig. 4.
  • the current invention provides interconnecting control nodes of one control network or various control networks via a standard TDM link. It facilitates the interface to the existing standard digital networks and provides a cost-effective solution to both wireless and wireline connections.
  • Figs. 6a to 6d illustrates some application examples to interconnect communications and control networks between buildings. Referring to Fig. 6a, two separate wireless links 64 and 70 are used to inter-connect communications devices
  • TDM multiplexer MUX
  • Radio transceivers 62 and 62' are used to inter-connect multiplexers 61 and 61' respectively.
  • the interface between MUX 61 or 61' and radio transceiver 62 or 62' uses a TDM standard such as Tl or El or higher-capacity
  • both MUX 61, 61' and radio transceiver 62 or 62' are widely available communications products from various manufacturers. Since the control networks 65 and 65' do not use a standard TDM format, the inter-connection of the control networks 65 and 65' between two buildings has to use a different set of radio transceivers 63 and 63'. Although such a radio transceiver 63 or 63' is commercially available, two separate wireless links 64 and 70 are employed in this case. Two sets of radio transceivers and two sets of wireless channels are required.
  • the TDM gateways 66 and 66' in accordance with the present invention are used to transport control messages of the control networks 65 and 65' over a single TDM wireless link 64.
  • the output of each TDM gateway 66 and 66' can be directly connected to respective standard TDM MUX 61 and 61'.
  • the inter-connection between the two buildings A and B can be implemented with only one wireless link 64 with a single set of standard TDM radio transceivers 62 and 62'.
  • the present invention provides a more cost-effective solution. Both cost and spectrum requirement are greatly reduced.
  • FIG. 6c it can be seen that the inter-connection between the two buildings A and B can also use one single wireline link 67 using a TDM standard such as Tl, El or HDSL.
  • Figs. 6b and 6c show application examples of the present invention in private networks where wireless or wireline links belong to a private owner such as a company. Since TDM standards are widely used in public digital networks, the present invention is also applicable to inter-connections of distant control networks via the existing public network 69 as shown in Fig. 6d.
  • Links 68 connect the TDM Multiplexers in different buildings A, B, C, and D to their nearest Central Offices (CO). These links can be wireline or wireless. The connections between the CO's are parts of the public network.
  • the invention provides interconnecting control nodes of one train monitoring and or control network or various train monitoring and or control networks via a standard TDM link. It facilitates the interface to existing standard digital networks and provides a cost-effective solution to both wireless and wireline connections.
  • Figs. 7a to 7e illustrates some application examples to interconnect communications and train monitoring and or control networks between cars according to the invention.
  • two separate wireless links 64 and 70 are used to inter-connect communications devices 53, 53' and train monitoring and or control networks 65, 65' between two cars A and B.
  • various communications devices, respectively 53 and 53' are connected to a respective standard TDM multiplexer (MUX) 61 and 61'.
  • MUX standard TDM multiplexer
  • Radio transceivers 62 and 62' are used to inter-connect multiplexers 61 and 61' respectively.
  • the interface between MUX 61 or 61 ' and radio transceiver 62 or 62' uses a TDM standard such as Tl or El or higher-capacity DS3, both MUX 61, 61' and radio transceiver 62 or 62' are widely available communications products from various manufacturers.
  • the train monitoring and or control networks 65 and 65' do not use a standard TDM foimat, the inter-connection of the train monitoring and or control networks 65 and 65' between two cars uses a different set of radio transceivers 63 and 63'.
  • a radio transceiver 63 or 63' is commercially available, two separate wireless links 64 and 70 are employed in this case. Two sets of radio transceivers and two sets of wireless channels are required.
  • the TDM gateways 66 and 66" in accordance with the present invention are used to transport control messages of the train monitoring and or control networks 65 and 65' over a single TDM wireless link 64.
  • the output of each TDM gateway 66 and 66' can be directly connected to respective standard TDM MUX 1 and 61'.
  • the inter-connection between the two cars A and B can be implemented with only one wireless link 64 with a single set of standard TDM radio transceivers 62 and 62'.
  • the present invention provides a more cost-effective solution. Both cost and spectrum requirements are greatly reduced.
  • Fig. 7c it can be seen that the interconnection between the two cars A and B can also use one single wireline link 67 using a TDM standard such as Tl, El or HDSL.
  • Fig. 7f illustrates some of the control and monitoring components, such as propulsion or throttle control, brake control, air pressure control, and temperature monitoring.
  • Communications components include an intercom and a close circuit television device.
  • the inter-car connection may be wireless 64 or wireline 67.

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  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Automation & Control Theory (AREA)
  • Multimedia (AREA)
  • Computing Systems (AREA)
  • Time-Division Multiplex Systems (AREA)

Abstract

Un dispositif (10) relais d'interconnexion de réseaux (11) interconnecte des réseaux de commande via une liaison (13) à multiplexage par répartition dans le temps (MRT), de façon à constituer un réseau de commande/communication intégré. Le relais ou la passerelle MRT permet la transparence des communications entre réseaux de commande du même type et assure l'interconnexion entre réseaux de commande de différents types. Il connecte un réseau de commande ou un noeud de commande (12) à la liaison MRT. Celle-ci a une structure en demi-relais ou en demi-passerelle, et possède une pile complète de fonctions qui permettent à la couche physique, à la couche liaison de données et à la couche réseau de communiquer avec un réseau de commande selon le protocole utilisé par ledit réseau. Un protocole intermédiaire commun, ainsi que les piles de fonctions associées à la couche physique, à la couche liaison de données et à la couche réseau fonctionnant par l'intermédiaire de la liaison MRT, sont spécifiés.
PCT/CA1998/000283 1997-03-26 1998-03-26 Procede et dispositif pour interconnecter des reseaux de commande via une liaison a multiplexage par repartition dans le temps WO1998043392A1 (fr)

Priority Applications (1)

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AU68175/98A AU6817598A (en) 1997-03-26 1998-03-26 Method and apparatus for interconnecting control networks with time division multiplexing link

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US4161397P 1997-03-26 1997-03-26
US60/041,613 1997-03-26
US4891897P 1997-06-06 1997-06-06
US60/048,918 1997-06-06
US92623997A 1997-09-08 1997-09-08
US08/926,239 1997-09-08

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Cited By (6)

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EP1010601A1 (fr) * 1998-12-08 2000-06-21 Deutsche Bahn Aktiengesellschaft Système de communication de données dans un train avec bus maítre
EP1010602A1 (fr) * 1998-12-08 2000-06-21 Deutsche Bahn Aktiengesellschaft Système de communication de données
EP1065127A1 (fr) * 1999-06-28 2001-01-03 Deutsche Bahn Ag Système de conversion de protocole de communication entre un bus de véhicule et un bus de train dans un système de communication en train
CN100382544C (zh) * 2003-09-05 2008-04-16 华为技术有限公司 传统电话交换网向下一代网络改造的实现方法及过渡网络
EP2026509A1 (fr) * 2007-08-14 2009-02-18 Alstom Transport S.A. Unité de transport
RU186187U1 (ru) * 2015-06-23 2019-01-11 Сименс Акциенгезелльшафт Устройство управления для транспортного средства

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Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1010601A1 (fr) * 1998-12-08 2000-06-21 Deutsche Bahn Aktiengesellschaft Système de communication de données dans un train avec bus maítre
EP1010602A1 (fr) * 1998-12-08 2000-06-21 Deutsche Bahn Aktiengesellschaft Système de communication de données
DE19856540C2 (de) * 1998-12-08 2001-11-08 Deutsche Bahn Ag Datenkommunikationssystem im Zug
DE19856539C2 (de) * 1998-12-08 2001-11-08 Deutsche Bahn Ag Datenkommunikationssystem im Zug mit Masterbus
EP1065127A1 (fr) * 1999-06-28 2001-01-03 Deutsche Bahn Ag Système de conversion de protocole de communication entre un bus de véhicule et un bus de train dans un système de communication en train
CN100382544C (zh) * 2003-09-05 2008-04-16 华为技术有限公司 传统电话交换网向下一代网络改造的实现方法及过渡网络
EP2026509A1 (fr) * 2007-08-14 2009-02-18 Alstom Transport S.A. Unité de transport
FR2920066A1 (fr) * 2007-08-14 2009-02-20 Alstom Transport Sa Unite de transport
RU186187U1 (ru) * 2015-06-23 2019-01-11 Сименс Акциенгезелльшафт Устройство управления для транспортного средства

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