Safety Message Transmission in Vehicular Communication Networks

Emerging vehicular safety applications require low latency communications and reliable packet dissemination for life saving safety messages. Significant developments have taken place over the past few years. IEEE WAVE and ISO CALM have been developed as international standards for ITS applications. Both WAVE and CALM support multichannel operations and use CSMA/CA as channel access mechanism. WAVE may impose a latency of 54 milliseconds for enabling multi-channel operations. CSMA/CA method can experience unpredictable delay and packet drop when channel is congested. In this paper, we propose an innovative technique to increase channel coverage and reduce latency for safety messages in multi-channel vehicular environments. We also propose an efficient congestion control protocol for vehicular communication networks that use CSMA/CA channel access mechanism. The proposed congestion control protocol guarantees that safety messages gain channel access while contending with other messages. Technologies presented in this paper improve reliability of the safety message dissemination and reduce latency for safety message transmission. ITS World Congress 2010 This work may not be copied or reproduced in whole or in part for any commercial purpose. Permission to copy in whole or in part without payment of fee is granted for nonprofit educational and research purposes provided that all such whole or partial copies include the following: a notice that such copying is by permission of Mitsubishi Electric Research Laboratories, Inc.; an acknowledgment of the authors and individual contributions to the work; and all applicable portions of the copyright notice. Copying, reproduction, or republishing for any other purpose shall require a license with payment of fee to Mitsubishi Electric Research Laboratories, Inc. All rights reserved. Copyright c ©Mitsubishi Electric Research Laboratories, Inc., 2010 201 Broadway, Cambridge, Massachusetts 02139