Tham khảo tài liệu 'advances in vehicular networking technologies part 2', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | 22 Advances in Vehicular Networking Technologies message propagation will have a maximum bound equal to vV2I while for reverse message propagation range the maximum bound is vV2I. The definitions for forward and reverse message propagation rates are given below respectively. Definition Forward Message Propagation rate the forward message propagation rate when a vehicle is communicating via V2V is in the range c iff- . In contrast when a vehicle communicates via V2I the forward message propagation rate is in the range c vV2I . Definition Reverse Message Propagation rate the reverse message propagation rate when a vehicle communicates via V2V is in the range c v V while for vehicles communicating via V2I the range of reverse message propagation rate is c vV2I . V2X algorithm This section illustrates how V2X takes a protocol switching decision. The algorithm for handing over from V2V to V2I and vice versa is described by its pseudocode in Figure 11. It is mainly based on i the Infrastructure Connectivity IC parameter which gives information if a vehicle is able to connect to an RSU and on ii the optimal path detection technique. The algorithm accepts one input . the vehicle s IC and returns the actual message propagation rate . vV2V vV2I . Input IC vV2V if a vehicle communicates via V2V vV2I if a vehicle communicates via V2I while IC 0 do I A vehicle is connected via V2V vV2V end else if IC 1 then I Optimal path detection vV2Ior vV2V end end if A vehicle communicates with an RSU via V2I then the RSU tracks the destination s position if Destination vehicle is inside the actual RSUs coverage then Direct link from RSU to destination vehicle else I The actual RSU will forward the message to next RSU end end end Fig. 11. Algorithm for protocol switching decisions in V2X Seamless Connectivity Techniques in Vehicular Ad-hoc Networks 23 Let us consider the following VANET scenario. A source vehicle is communicating with other vehicles relay via V2V in a sparsely .
