Communication system using time division multiplex signal transmission

• US 5,737,335 A
• Filed: 11/09/1995
• Issued: 04/07/1998
• Est. Priority Date: 11/09/1994
• Status: Expired due to Fees

• Current Assignee: ALPS Electric Company Limited (Alps Alpine Co., Ltd.)
• Original Assignee: ALPS Electric Company Limited (Alps Alpine Co., Ltd.)
• Inventors: Miura, Yukio, Kawata, Toshihiko, Shibazaki, Ken, Mizuta, Ken
• Primary Examiner(s): Kizou, Hassan
• Application Number:
  US08/555,540
• Time in Patent Office: 880 Days
• Field of Search: 370/16, 370/53, 370/58.1, 370/58.3, 370/67, 370/85.1, 370/85.6, 370/85.7, 370/95.1, 370/95.2, 370/110.1, 370/431, 370/442, 370/444, 370/445, 370/447, 370/458 , 370/461, 370/468, 370/498, 307/10.1, 340/825.2, 340/325.51
• US Class Current: 370/444
• CPC Class Codes: B60R 16/0315 using multiplexing techniques multiplexing for transmission of signals G08C15/00; multiplexing for electrical communication in general H04J
• CPC Class Codes: H04J 3/1682 Allocation of channels according to the instantaneous demands of the users, e.g. concentrated multiplexers, statistical multiplexers
• CPC Class Codes: H04L 12/40156 by using dedicated slots associated with a priority level
• CPC Class Codes: H04L 12/403 with centralised control, e.g. polling
• CPC Class Codes: H04L 2012/40273 the transportation system being a vehicle

Abstract

A multiplex communication system in which operational data is transmitted to a bus line at different frequencies according to the necessity of transmission. Further, transmitting and receiving nodes are identified without having to include address data with the transmitted message data, thereby avoiding a time lag in control processing of vehicle-mounted equipment. In accordance with a first embodiment, a plurality of data signals which are transmitted via a bus line from a plurality of node devices, to at least one of a plurality of end node devices to be controlled, are divided into a plurality of degrees according to the necessity of transmission. Operational date signals falling into the greatest degree of transmission necessity are transmitted once in every cycle, while data signals falling into the lesser degrees of transmission necessity are transmitted once in every few cycles according to the degree of necessity. In a second embodiment, one of a plurality of node devices connected to a bus line serves as a master node device and sets the transmission cycle of message data transmitted onto the bus line. This cycle is set so as not to cause a time lag in data processing executed by the respective node devices. Each time interval between the start pulses is divided into a plurality of time slots. The time slots have been allocated to the individual node devices so that message data can be transmitted from the respective devices in the associated time slots.

Claims

1. A multiplex communication system in which a plurality of data signals are transmitted during a plurality of transmission cycles via a bus line from a plurality of node devices to at least one of a plurality of end devices, each transmission cycle being divided into a plurality of equal-length time slots, the multiplex communication system comprising:

means for controlling transmission of the data signals according to a necessity of transmission, wherein a first data signal having a greatest degree of transmission necessity is transmitted in a first time slot during each of the plurality of transmission cycles, while second and third data signals having a lesser degree of transmission necessity are transmitted in a second time slot in a predetermined alternating sequence such that each of the second and third data signals is always transmitted every n transmission cycles, where n is an integer greater than or equal to two;

wherein connections between said plurality of node devices and said bus line, and connections between said plurality of end devices and said bus line are selectively switched by a plurality of change-over switches which are controlled by a control apparatus.

2. A multiplex communication system according to claim 1, wherein said plurality of node devices are mounted in a vehicle, and said plurality of end devices are mounted in the vehicle and controlled by the operation of said plurality of node devices.

3. A multiplex communication system in which a plurality of data signals are transmitted during a plurality of transmission cycles via a bus line from a plurality of node devices to at least one of a plurality of end devices, each transmission cycle being divided into a plurality of equal-length time slots, the multiplex communication system comprising:

means for controlling transmission of the data signals according to a necessity of transmission, wherein a first data signal having a greatest degree of transmission necessity is transmitted in a first time slot during each of the plurality of transmission cycles, while second and third data signals having a lesser degree of transmission necessity are transmitted in a second time slot in a predetermined alternating sequence such that each of the second and third data signals is always transmitted every n transmission cycles, where n is an integer greater than or equal to two;

wherein said plurality of node devices are mounted in a vehicle, and said plurality of end devices are mounted in the vehicle and controlled by the operation of said plurality of node devices.

4. A multiplex communication system according to claim 3, wherein said data signals are divided into degrees of transmission necessity based on an urgency of transmitting said data signals.

5. A multiplex communication system comprising:

a plurality of node devices connected to a bus for transmitting a plurality of data signals during a plurality of transmission cycles via the bus line to at least one of a plurality of end devices, each transmission cycle being divided into a plurality of time slots, each time slot having a fixed length, and

means for controlling transmission of the data signals according to a necessity of transmission, wherein a first data signal having a greatest degree of transmission necessity is transmitted in a first time slot during each of the plurality of transmission cycles, while second and third data signals having a lesser degree of transmission necessity are transmitted in a second time slot in a predetermined alternating sequence such that each of the second and third data signals is always transmitted every n transmission cycles, where n is an integer greater than or equal to two;

wherein said data signals are divided into degrees of transmission necessity based on an urgency of transmitting said data signals.

6. A multiplex communication system comprising a plurality of node devices connected to a bus line such that each node device cyclically transmits and receives message data signals on said bus line and executes processing of the received data,

wherein one of said node devices functions as a master node device so as to determine a transmission cycle of the message data signals from all the node devices and to determine a transmission timing within said transmission cycle at which each of said node devices, including the master node device, transmits message data signals onto said bus line, said transmission timing being associated with each of said node devices, so that each of said devices sends the message data signals addressed to another device onto said bus line at said transmission timing determined by said master node device, and

wherein a time slot provided at said transmission timing associated with each of said node devices is divided into a plurality of sub-time slots, and said sub-time slots are arranged to correspond to the individual node devices to receive the message data transmitted from one of said node devices.

7. A multiplex communication system according to claim 6,

wherein each of said node devices, including said master node device, include a CPU, wherein the CPU of said master node device determines said transmission cycle and said transmission timing associated with each of said node devices arranged within said cycle, while the CPU of each of said node devices, including said master node device, controls the transmission timing so that the message data signals is transmitted from said node device at the time slot determined by the CPU of said master node device.

8. A multiplex communication system according to claim 6, wherein a second one of said node devices performs the functions of said master node device if said master node device fails to operate.

9. A multiplex communication system according to claim 6,

wherein a second one of said node devices performs the functions of said master node device if said master node device fails to operate, and

wherein each of said node devices, including said master node device, include a CPU, wherein the CPU of said master node device determines said transmission cycle and said transmission timing associated with each of said node devices arranged within said cycle, while the CPU of each of said node devices, including said master node device, controls the transmission timing so that the message data signals are transmitted from said node device at the time slot determined by the CPU of said master node device.

10. A multiplex communication system in which a plurality of data signals are transmitted during a plurality of transmission cycles via a bus line from a plurality of node devices to at least one of a plurality of end devices, each transmission cycle being divided into a plurality of time slots, the multiplex communication system comprising:

means for controlling transmission of the data signals according to a necessity of transmission, wherein a first data signal transmitted from a first node device and having a greatest degree of transmission necessity is transmitted in a first time slot during each of the plurality of transmission cycles, while second and third data signals respectively transmitted from second and third node devices and having a lesser degree of transmission necessity are alternately transmitted in a second time slot during every two or more transmission cycles;

wherein said means for controlling transmission of said data signals includes a control apparatus for generating control signals according to a program stored in a storage unit; and

wherein a connection between said first node device and said bus line occurs through a first change-over switch, and connections between said second and third node devices and said bus line occur through said first change-over switch and a second change-over switch, and said first and second change-over switches are controlled by said control signals generated by said control apparatus.

11. A multiplex communication system comprising:

a bus;

a first node device connected to the bus for generating a higher-priority data signal;

a second node device connected to the bus for generating a first lower-priority data signal;

a third node device connected to the bus for generating a second lower-priority data signal; and

means for controlling the first, second and third nodes in accordance with a fixed transmission sequence such that during a first transmission cycle, the higher-priority data signal and the first lower-priority data signal are always transmitted in a predetermined order on the bus as a first combination of data signals, during a second transmission cycle, the higher-priority data signal and the second lower-priority data signal are always transmitted in the predetermined order on the bus as a second combination of data signals, and during subsequent transmission cycles, the first combination of data signals and the second combination of data signals are retransmitted on the bus, thereby transmitting the higher-priority data signal at least twice as often as each of the first and second lower-priority data signals.