Research Article
A Road Layout Based Broadcast Mechanism for Urban Vehicular Ad Hoc Networks
| Reception of a broadcast message | | If (new message) | | Save the message | | Set FT | | If (intersection vehicle) | | Set IFT = | | Else if (intersection within TR && approaching intersection) | | Set IFT = | | Else | | If (FT is running) | | Cancel FT | | If (IFT is running) | | If (implicit ACK from all branches where neighbors exist ∥ msg from intersection vehicle) | | Cancel IFT | | Else | | Keep waiting implicit ACK | | If (RT is running) | | Cancel RT | | If (IRT is running) | | If (implicit ACK from all branches where neighbors exist) | | Cancel IRT | | Else | | Keep waiting implicit ACK | | If (NFT is running) | | Cancel NFT | | Timer expiration | | If | | Broadcast the message | | If (intersection vehicle) | | Set IRT = | | Else | | Set RT = | | Wait for implicit ACK | | Else if (IFT) | | Broadcast the message | | Set IRT = | | If (FT is running) | | Cancel FT | | Else if (RT ∥ IRT) | | If (num. of rebroadcast by RT or IRT less than maximum) | | Broadcast the message | | Num. of rebroadcast by RT or IRT ++ | | Set RT or IRT = | | Wait for implicit ACK | | Arrival at intersection zone | | If (IRT is running) | | Reset IFT = | | Meet new neighbor vehicles without message | | If (FT, IFT, RT, and IRT are NOT running) | | Set NFT |
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