tailieunhanh - Báo cáo hóa học: " Reaching spatial or networking saturation in VANET"

Tuyển tập các báo cáo nghiên cứu về hóa học được đăng trên tạp chí hóa hoc quốc tế đề tài : Reaching spatial or networking saturation in VANET | Ozturk et al. EURASIP Journal on Wireless Communications and Networking 2011 2011 174 EURASIP Journal on . http content 2011 1 174 Wireless Communications and Networking a SpringerOpen Journal RESEARCH Open Access Reaching spatial or networking saturation in VANET Serkan Ozturk1 Jelena Misic2 and Vojislav B Misic2 Abstract In this article we investigate the network transition between non-saturation and saturation regimes for a Vehicular Ad hoc Network VANET which is composed of mobile nodes. We combine vehicular traffic theory queuing model and Markov chain to evaluate the performance of the network under spatial or networking saturation for multiple data classes over control channel and service channel. Our results indicate that the vehicle density growth can result in saturation of wireless medium around the roadside unit RSU further resulting in buffer overflows at on board units OBUs . We also investigate the network saturation points for different transmission ranges of a RSU. Our results show that RSU s transmission coverage has to be chosen with respect to data patterns of OBUs minimal distance between vehicles and number of lanes in order to avoid network saturation condition. Keywords IEEE vehicular traffic theory free-flow regime network saturation 1 Introduction Vehicular Ad hoc Network VANET is a special type of Mobile Ad hoc Network MANET based on short-range communications among moving vehicles and between vehicles and roadside units RSUs . IEEE is referred to as dedicated short-range communications DSRC standard for wireless access in vehicular environment WAVE . For DSRC 75MHz of licensed spectrum at GHz has been allocated. This 75MHz band is divided into one central control channel CCH and six service channels SCHs as shown in Figure 1. CCH is dedicated for transmission of traffic safety messages while SCHs are dedicated to transfer of various application data. Both CCH and SCH support four data classes