Maximum Delay Analysis of Fixed Backoff in IEEE 802.11 Considering Significant Interference for In-Vehicle Wireless Communication

In in-vehicle wireless communication, each in-vehicle sensor terminal transmits small data in a cycle within which all terminals must transmit data successfully. Clarifying the delay characteristics in such networks is useful for the system design. This paper proposes a maximum delay distribution analysis method for the fixedCWmethod in CSMA/CA mission-critical periodic communications. The proposed method focuses on the fact that the upper bound of the distribution of the number of collisions and the transition of the number of terminals can be approximated by a binomial distribution. In the first step, the distribution of the total number of slots required for all terminals departure is derived from a two-dimensional Markov-chain model. In the second step, the total slot number distribution is converted into a real-time scale according to the events occurring in a slot, and the upper bound of the maximum delay distribution is derived. This analytical method analytically derives the upper bound of the maximum delay distribution for an arbitrary number of terminals in the network with a fixed CW value while taking interference induced by competition terminals into account. The validity of the proposed method is demonstrated through comparison with computer simulation results.