Redundant message packet suppression for in-vehicle ad hoc network

• US 20090323579A1
• Filed: 06/27/2008
• Published: 12/31/2009
• Est. Priority Date: 06/27/2008
• Status: Active Grant

• Current Assignee: GM Global Technology Operations LLC (General Motors Company)
• Original Assignee: GM Global Technology Operations Incorporated (General Motors Company)
• Inventors: Mudalige, Upali Priyantha, Bai, Fan
• Granted Patent: US 8,050,188 B2
• Time in Patent Office: Days
• US Class Current: 370/315
• CPC Class Codes: H04L 45/32 Flooding denial of service attacks H04L63/1458
• CPC Class Codes: H04W 40/08 based on transmission power

Abstract

A method is provided for suppressing redundant packet message transmissions a multi-hop message delivery system. The vehicle receives message packets from any one of a plurality of vehicles within a broadcast range of the vehicle. The vehicle includes a buffer for holding the received message packets prior to re-broadcasting the message packets. A first estimation value is calculated as a function of a signal strength of the vehicle receiver for a respective received message packet. A second estimation value is calculated as a function of the buffer. A re-broadcast estimation threshold value is determined as a function of the first estimation value and the second estimation value. At least one triggering function is provided for generating an at least one triggering indicator. The respective message packet is re-broadcast in response to the re-broadcast estimation threshold value satisfying the at least one triggering indicator.

Claims

1. A method for suppressing redundant packet message transmissions in a vehicle having a multi-hop message delivery system, the vehicle having a receiver for receiving message packets from any one of a plurality of vehicles within a broadcast range of the vehicle, a transmitter for re-broadcasting the message packets to the plurality of nearby vehicles, the vehicle including a buffer for holding the received message packets prior to re-broadcasting the message packets, the method comprising the steps of:

calculating a first estimation value as a function of a signal strength of the vehicle receiver for a respective received message packet;

calculating a second estimation value as a function of the buffer;

determining a re-broadcast estimation threshold value as a function of the first estimation value and the second estimation value;

providing at least one triggering function for generating an at least one triggering indicator; and

re-broadcasting the respective message packet in response to the re-broadcast estimation threshold value satisfying the at least one triggering indicator.

2. The method of claim 1 wherein the first estimation value is determined by the formula:

3. The method of claim 2 wherein the second estimation value is determined by the formula:

4. The method of claim 3 wherein the re-broadcast estimation threshold is a time-based value represented by the formula:

5. The method of claim 4 wherein the at least one triggering function includes a timer and the at least one triggering indicator includes a respective count value, and wherein the message is re-broadcast when the timer counts to a count value equaling the re-broadcast estimation value.

6. The method of claim 5 wherein re-broadcasting the message packet is canceled if a redundant message is received prior to the count value equaling the re-broadcast estimation value.

7. The method of claim 3 wherein the re-broadcast estimation threshold is a probability-based value represented by the formula:

8. The method of claim 7 wherein the at least one triggering function includes a probability density function and the at least one triggering indicator includes a randomly generated value generated by the probability density function, and wherein the message is re-broadcast if the former probability-based value is greater than the latter randomly generated value.

9. The method of claim 3 wherein the re-broadcast estimation threshold is a hybrid-based value represented by the following formulas:

10. The method of claim 9 wherein re-broadcasting the message packet is canceled if a redundant message packet is received prior to the time-based value T_i expiring.

11. The method of claim 9 wherein the at least one triggering function includes a timer function and the at least one triggering indicator includes a respective count value generated by the timer function, and wherein the at least one triggering function further includes a probability density function and the at least one triggering indicator further includes a randomly generated value generated by the probability density function, and wherein the re-broadcast estimation threshold value satisfies the at least one triggering function for re-broadcasting the message packet if the timer function counts to a count value equaling the time-based value prior to receiving a redundant message and if the probability-based value is greater than the randomly generated value.

12. The method of claim 1 wherein the first estimation value and the second estimation value are determined in real-time.