Tham khảo tài liệu 'mobile ad hoc networks applications part 3', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | Modeling and Simulation of Vehicular Networks Towards Realistic and Efficient Models 61 Medium Access Control MAC protocol design MAC protocols will have to cope with an increased number of hidden vehicles due to other vehicles obstructing them. Impact on the design of routing protocols If vehicles as obstacles are not accounted for the impact on routing protocols is represented by an overly optimistic hop count in the process of routing next hop neighbors are selected that are actually not within the reach of the current transmitter thus inducing an unrealistic behavior of the routing protocol as the message is considered to reach the destination with a smaller number of hops than it is actually required. As an especially important class of routing protocols safety messaging protocols are often modeled and evaluated using distance information only. As our results have shown not accounting for vehicles as obstacles in such calculations results in the overestimation of the number of reachable neighbors which yields unrealistic results with regards to network reachability and message penetration rate. Therefore it is extremely important to account for vehicles as obstacles in V2V especially since safety applications running over such protocols require that practically all vehicles receive the message thus posing very stringent requirements on the routing protocols. For these reasons it is more beneficial to design routing protocols that rely primarily on the received signal strength instead of the geographical location of vehicles since this would ensure that the designated recipient is actually able to receive the message. However even with smart protocols that are able to properly evaluate the channel characteristics between the vehicles in case of lower market penetration rates of the communicating equipment the vehicles that are not equipped could significantly hinder the communication between the equipped vehicles this is another aspect of routing protocol
