Multiplex transmission method

• US 5,596,588 A
• Filed: 03/27/1992
• Issued: 01/21/1997
• Est. Priority Date: 03/28/1991
• Status: Expired due to Term

• Current Assignee: Mazda Motor Corporation
• Original Assignee: Mazda Motor Corporation
• Inventors: Nobutoki, Yoshikazu, Satomura, Shigeyuki, Hideshima, Masao, Sone, Akira
• Primary Examiner(s): Gordon, Paul P.
• Application Number:
  US07/858,538
• Time in Patent Office: 1,761 Days
• Field of Search: 371/32, 371/35, 371/53, 371/33, 371/34, 370/77
• US Class Current: 714/748
• CPC Class Codes: H04L 1/08 by repeating transmission, e.g. Verdan system H04L1/1858 and H04L1/189 take precedence
• CPC Class Codes: H04L 12/4135 using bit-wise arbitration
• CPC Class Codes: H04L 2012/40273 the transportation system being a vehicle

Abstract

A multiplex transmission method in which time-divisional multiplex transmission operations are performed among a plurality of communication nodes, and every time a node transmits a new signal, it changes the state of a re-transmission check bit added to the signal. When a signal is re-transmitted, each node sets the re-transmission check bit to be the same as that of the new signal to be re-transmitted. Each node can properly determine whether or not a reception signal is a new or re-transmission signal for the self node.

Claims

1. A multiplex transmission method for performing time-divisional distributed multiplex transmission operations among a plurality of communication nodes, comprising the steps of:

adding a check bit at a transmission node to a signal transmitted from said transmission node, said transmission node being one of said plurality of communication nodes and said check bit indicating a status of said signal;

causing said check bit to have a predetermined change every time a new signal is transmitted from said transmission node to a reception node which is one of said plurality of communication nodes, said predetermined change giving rise to a change of a value of said check bit which is different from a value of a check bit added to a previously transmitted signal;

detecting at said transmission node presence or absence of a communication node which has not normally received the signal transmitted from said transmission node, in said plurality of communication nodes;

re-transmitting the signal from said transmission node, without changing the status of said check bit, in accordance with a detection result obtained at said detecting step; and

determining, at said reception node which has received said signal, whether said signal is a re-transmitted signal on a basis of a comparison result between a first status of a check bit associated with a previously received signal and a second status of a check bit associated with a currently received signal;

wherein if the first status and the second status agree, it is determined at said determining step that the received signal is the re-transmitted signal.

2. The method according to claim 1, wherein said detecting step includes determining that said reception node has not normally received a signal transmitted from said transmission node based on the content of a reception acknowledge signal.

3. The method according to claim 1, further comprising the steps of:

adding a code to a transmission signal from each of the plurality of communication nodes, said code representing a priority order for the multiplex transmission operations, and

determining that a transmission signal from a communication node having a low priority has not normally been received when said code undergoes a predetermined change after a signal transmission.

4. The method according to claim 1, wherein said check bit is located at the head of a transmission signal.

5. The method according to claim 1, wherein a signal is continuously re-transmitted until the reception node normally receives the signal transmitted from said transmission node.

6. The method according to claim 1, wherein when it is detected that said reception node has not normally received said signal transmitted from said transmission node, re-transmission of said signal is executed a predetermined number of times, and thereafter, is stopped.

7. The method according to claim 1, further comprising the steps of:

said reception node determining a recovery from a transmission/reception disabled state; and

determining that a signal received first from said transmission node after the recovery of said reception node from said disabled state is a new signal.

8. The method according to claim 1, further comprising the steps of:

said reception node determining a recovery by said transmission node from a transmission/reception disabled state; and

determining that a signal received first from said transmission node after the recovery of said transmission node from said disabled state is a new signal.