The following patches have been developed and validated with empirical data to improve the accuracy of PHY and MAC layers for high-density vehicle-to-vehicle (V2V) communications. Although, the patches are more general and may be used in other wireless scenarios.
- MAC Layer Patches
- Backoff Timer Countdown Correction: Adjusts the countdown procedure of backoff timer when nodes are using 802.11 Enhanced Distributed Channel Access (EDCA) as the MAC layer control model.
- Additional Backoff Timer Trigger: Initiates an additional backoff when a channel access is requested and the channel is in either IFS idle or ack timeout, while the backoff timer is zero.
- Queue Management Policy: Provides an option which allows to drop the oldest packet in the packet queue instead of the newest packet when the queue is full.
- Physical Layer Patches
- Frame Capture: Allows the nodes to switch to a stronger signal during an ongoing reception of a packet with a weaker signal.
- Other Patches
- Mobility Helper: Improves the accuracy of mobility model when GPS data is used as the mobility trace input.
Download the PDF version of the patch documentation
These patches have been developed jointly at WINLAB, Rutgers University and West Virginia University as part of the V2V safety communications scalability activity of the Interoperability Issues of Vehicle-to-Vehicle Based Safety Systems (V2V-Interoperability) Project headed by the Crash Avoidance Metrics Partnership (CAMP) Vehicle Safety Communications 3 (VSC3) Consortium, in partnership with the United States Department of Transportation (USDOT).