T slot is calculated as the summation of the average empty slot time, the average successful transmission period, and the average collision period.
where P i succ, L, T, T F, σ, and P tr denote the probability that a successful transmission for class i occurs, average MSDU size, the average successful transmission time, the average collision time, a slot time, and the probability that the channel is busy, respectively.
The average successful payload information transmitted for class i nodes that are within the coverage area of RSU is computed as follows Z i = Average payload information for class i transmitted in a slot time Average length of a slot time × Mean residence time for class i Z i = p t r p s, i E [ M ] ( 1 - p t r ) σ + p t r p s E [ T s ] + p t r ( 1 - p s ) E [ T c ] × E [ T 1, i ] (18).
where W ¯ is the average backoff value, σ is the slot time, and T indicates the total time required for sending respective packet.
Because the sender node stays in any state until the upcoming idle slot, the average time to stay in any state in Fig. 6 equals the average slot size E[ S].
Moreover, indicates the average length of non-frozen backoff time in a time slot, where is defined as the size of a slot time [27].
Finally, based on the calculation of average time slot size, the system throughput and channel access delay are derived.
Because the system throughput can be expressed as the ratio of the total length of the DATA frame successfully transmitted in bits to the average time slot, it corresponds to Eq. (22).
In terms of training period, the shortest period was 1 week (25, 37) and the longest one was 2 years (38), with the average time slot from 4 to 8 weeks.
