Multiplex transmission method

• US 5,289,466 A
• Filed: 03/27/1992
• Issued: 02/22/1994
• Est. Priority Date: 03/27/1991
• Status: Expired due to Term

• Current Assignee: Mazda Motor Corporation
• Original Assignee: Mazda Motor Corporation
• Inventors: Nobutoki, Yoshikazu, Sone, Akira, Satomura, Shigeyuki, Hideshima, Masao
• Primary Examiner(s): Chin, Wellington
• Application Number:
  US07/858,531
• Time in Patent Office: 697 Days
• Field of Search: 370/85.2, 370/85.3, 370/85.6, 370/85.1, 370/108, 370/100.1, 370/103, 340/825.5, 340/825.51, 340/825.06, 340/825.14
• US Class Current: 370/461
• CPC Class Codes: H04L 12/4135 using bit-wise arbitration
• CPC Class Codes: H04L 2012/40273 the transportation system being a vehicle

Abstract

In a multiplex transmission method, refresh transmission operations at a predetermined period, and event transmission operations are time-divisionally performed in a multiplex transmission mode, and a predetermined non-transmission time is set before start of each refresh transmission operation. When another transmission operation is performed within the non-transmission time, a communication is performed, while the predetermined period of the refresh transmission operations is properly permitted to be delayed to assure the non-transmission time for such a communication state.

Claims

1. A multiplex transmission method, in which time-divisional distributed multiplex transmission operations are performed among a plurality of communication nodes each having a clock for managing its own transmission timing, comprising the steps of:

(a) setting a first predetermined period of time for a refresh transmission operation to be performed at each of said plurality of communication nodes;

(b) setting a second predetermined period of time as a non-transmission time before the refresh transmission operation is started;

(c) detecting whether a transmission operation is performed by self communication node or other communication nodes within the second predetermined period of time;

(d) starting the refresh transmission operation after an elapse of a third predetermined period of time if it is detected in step (c) that the transmission operation is performed, wherein said third predetermined period of time is longer than or equal to the second predetermined period of time and begins at the start of the latest transmission operation performed by said self communication node or said other communication nodes so as to assure the non-transmission time; and

(e) starting the refresh transmission operation after an elapse of the second predetermined period of time if it is not detected in step (c) that the transmission operation is performed;

and wherein each of said plurality of communication nodes delays its own refresh transmission period by extending the first predetermined period of time for a period determined by said second and third predetermined periods of time, the determined period is used as an upper limit of a delay time of the refresh transmission operation and the refresh transmission period is delayed once before starting the refresh transmission operation in step (d) even when another transmission operation is performed by said self communication node or said other communication nodes after an elapse of said second predetermined period of time.

2. The method according to claim 1, wherein each of said plurality of communication nodes transmits information in a refresh transmission operation regardless of the presence/absence of a change in content of its own transmission information.

3. The method according to claim 1, wherein a specific node among said plurality of communication nodes serves as a master node to manage the refresh transmission timing.

4. The method according to claim 1, wherein when a refresh transmission operation is performed by another communication node within the non-transmission time, each of said plurality of communication nodes other than said another communication ode delays its own refresh transmission period by a predetermined period of time to assure the non-transmission time.

5. The method according to claim 1, wherein when an event transmission operation is performed by a self or another communication node among said plurality of communication nodes within the non-transmission time, each of said plurality of communication nodes delays its own refresh transmission period by a predetermined period of time to assure the non-transmission time.

6. The method according to claim 1, wherein when inter-communications between arbitrary communication nodes among the plurality of communication nodes are started during the refresh transmission operation, the communication nodes, which are involved in the inter-communications, count a predetermined transmission period of their refresh transmission operations, and the communication nodes, which are not involved in the inter-communications, perform refresh transmission operation while inhibiting the refresh transmission period from being delayed by the predetermined period of time.

7. The method according to claim 6, wherein the communication nodes, which are involved in the inter-communications, count the predetermined transmission period of their refresh transmission operations during the inter-communications, and perform the first refresh transmission operation after termination of the inter-communications at a predetermined inherent period from the last refresh transmission timing in the inter-communications.

8. The method according to claim 6, wherein the communication nodes, which are not involved in the inter-communications, perform refresh transmission operations while inhibiting the refresh transmission period from being delayed by the predetermined period of time, and perform the first refresh transmission operation after termination of the inter-communications at a predetermined inherent period from the last refresh transmission timing in the inter-communications.