The system performance metrics including the queue length, response time and the system throughput will be evaluated as follows.
The comparison is performed in terms of different performance indices including average queue length, system throughput, and expected waiting time.
For the performance prediction of machining system, it is important to provide the expressions for key indices including the queue length.
As mentioned in 2.4, four customer satisfaction indexes are set up to the threshold, including maximum queue length L max, average queue length ( overline{L} ), normalized average queue length for each swapping demand ( overline{{mathrm{L}}_{unit}} ), and probability P η of queue length longer than some value, see formula (2), (3), (4) and (5).
To calculate the backlog, each station maintains a matrix that includes the approximate queue length of its neighbors.
Various system metrics including the mean queue length, machine availability, throughput, etc., are derived to determine the performance of the machining system.
The traffic variables include: traffic volume, maximum queue length, shock wave characteristics (e.g. shock wave speed and shock wave area), and the platoon ratio.
The latter one includes throughput, packet delay time, packet queue length, packet waiting time, and packet drop ratio.
To indicate that a packet has been received successfully, the ACK also includes the station ID and the queue length of the best candidate relay known to the ACK sender.
The main scheduling policies include First Come First Serve (FCFS) [21], Maximum Queue Length (MQL) [21], Maximum Factored Queue Length (MFQL) [22], and Minimum Cost First (MCF) [16].
