دانلود رایگان مقاله تحلیل عملکرد خدمات پخش اولویت بندی شده در WAVE / 802.11p در IEEE

Abstract

In this paper, we propose a more accurate model to capture the prioritized broadcast service in WAVE/IEEE 802.11p and comprehensively analyze the related performance indicators accordingly. We construct a 2-D Markov chain to characterize the IEEE 802.11p EDCA backoff process and subsequently build a 1-D infinite discrete-time Markov chain to identify the contention period for establishing the relation between the transmission probabilities and the channel state. We also consider the impacts of the multichannel operation defined by IEEE 1609.4 in the modeling. Unlike most previous work, we define the transmission probability as a function of the fluctuating numbers of continuous idle slots, introduce a proactive backoff stage into the 2-D Markov chain to profile the backoff procedure where the transmission queue is empty, and characterize the access delay extension and transmission synchronization caused by channel switching. We perform extensive numerical analyses and investigate the access delay, packet delivery rate, and other performance indicators. The results uncover the relations among the metrics of concern underlying various priority access categories as a function of the experienced traffic loads. The effectiveness of the proposed performance model is faithfully verified by the simulation results.

5. Conclusions

This paper presented a comprehensive model to analyze the performance of a prioritized broadcast service in WAVE/IEEE 802.11p. We investigated two important QoS metrics for the broadcast applications—i.e., the access delay and PDR. The main contributions to the literature are summarized as (i) the transmission probability is not assumed to be a constant, and we deduced the formula of the transmission probability against various numbers of successive idle slots; (ii) we captured the backoff procedure where no packets wait in the queue, which is proved essentially by the analytical results in which the queue is always empty; and (iii) we considered the effects of the periodic CCH/SCH switching on the access delay and PDR, which is the main feature of WAVE. The simulation results faithfully verified that the analytical model is accurate and effective. Our future work will be focused on comprehensively modeling the impacts of the synchronization caused by multichannel operation.