摘要：The dynamic of changing network topology and vehicle density in VANET are causing the dynamic of message traffic intensity. This situation requires adaptability of channel management to provide the channel capacity dynamically and proportionally. The length of CCH interval in VANET represents the capacity of channel or service rate of vehicles. The fixed pattern of CCH/SCH interval as published by IEEE 802.11p/1609.4 would become the constraint of adaptability of vehicles in VANETs. Moreover it would affect to VANET performance inefficient. This research proposes an adaptive scheme of CCH/SCH interval which proportional with density of vehicles based on the number of vehicle connected each other’s. To show how effective the proposed adaptive scheme of CCH/SCH interval can afford to improve of VANET performance (compared to fixed interval scheme of current IEEE standard), we analyze by combining mobility model and queuing network model. We assume that statistically there is a steady state of VANET topology which can be analyzed by using queuing network model. We specified the real map of highway in Bandung city along 10 Km length to achieve the representative experimental result. The various specified of speeds are: 70-90 Km/h, 90-110 Km/h, and 110-130Km/h, while the various of density of vehicle are 15, 30, 45, 60, 75, and 90 vehicles along 10Km length of highway. All of experiments performed in two main scenarios, i.e. the fixed CCH/SCH interval, and adaptive CCH/SCH interval which compared each other to see the improvement. The analytical result examined by simulation method. The experimental results show the improvement of adaptive CCH/SCH interval. The improvement of average delay is 10ms, and the improvement of system throughput is 450 kbps.
