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Mobile Ad Hoc Networks Applications Part 5

Tham khảo tài liệu 'mobile ad hoc networks applications part 5', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | CARAVAN Context-AwaRe Architecture for VANET 131 Traffic Kind Communication Kind One-to-One One-to-Many One-to-All Topology Position Geocast Mobility Adapted to sparse networks Epidemic MDDV VADD Epidemic MDDV VADD Epidemic MDDV VADD General AODV DSR OLSR DREAM GSR MGF MORA MURU DRG GAMER IVG LBM MGF RBM TRADE DREAM Adapted to dense networks CBRP HSR CAR GPCR GPSR GeoGRID LBF OABS ODAM SB SOTIS UMB Table 1. Application-based taxonomy for routing protocols according to traffic density in VANET DUcourthial Khaled 2009 3.2 Location services There is a silent assumption of many geographic routing protocols that nodes know the destination position. Depending on the applications the requirements for location can vary considerably. Node position data and sometimes street topology obtained from GPS navigation system are usually sufficient. Other techniques for obtaining position of nodes include dead reckoning which works well for short periods of GPS unavailability cellular localization and relative distributed ad hoc localization. For many services information such as maximum range or direction of message propagation is enough. For the others - especially based on one-to-one communication - quite detailed knowledge is required. Some protocols like GSR find the destination node by flooding route request messages and only if this phase ends with success they can use their geographic properties. Other protocols use various independent location service mechanisms. For example in the CarTalk2000 project Reichardt et al. 2002 nodes position is distributed only to nodes within a given number of hops. Researchers involved in FleetNet project proposed Grid Location Service Li et al. 2000 using some nodes as location servers and Reactive Location Service Kasemann et al. 2002 finding position of destination on demand. The V-Grid Gerla et al. 2006 approach is based on two complementary location services - one in infrastructure network and the second in vehicular network. Node .