The latency of gaining α-reliability for message dissemination in vehicle-to-vehicle networks

In many Vehicular Ad-hoc Network applications, such as hazard warning and traffic coordination, the message dissemination in unreliable and highly mobile network environment is a key challenge. In order to understand the relationship between dissemination latency and reliability, we analyze the latency of gaining α-reliability that a node correctly receives a message with probability larger than α (0 <; α<; 1). Under a 1-Dimensional (1-D) network scenario with unreliable channel and constrained vehicle mobility, we derive the minimum latency of gaining almost sure α-reliability, denoted as t_min(α). Besides dissemination reliability requirement α, t_min(α) also depends on node´s original distance from the source, node mobility, channel reliability, and traffic flow. Numerical analysis discloses several interesting insights that 1) t_min(α) is dominated by the first attempt to send the message to a destination, 2) node mobility has little impact on t_min(α) in emergency information dissemination, and 3) transmission range and node density greatly affect dissemination latency and reliability.