基于启发式算法的VANETs性能优化研究

Improving VANET Performance based on Heuristic and Adaptive Fuzzy Logic Scheme

车载自组织网络(VANETs)是驾驶员在路上进行沟通和确保安全的革命性飞跃。针对VANETs的数据包传输问题,提出了一种改进的启发式算法,该算法考虑了干扰因素,基于碰撞丢包率,SINR和队列溢出,根据网络和交通情况优化传输功率和竞争窗尺寸。用Vanet Mobi Sim交通仿真软件构建VAENTs网络场景。结果表明,与传统的启发式算法比较,改进的启发式算法在端到端延迟影响较小的情况下,能够有效地降低数据包丢包率,提高数据包传递率和可靠性,进而提高吞吐量、降低端到端延迟和提高数据包传输的可靠性。

Rapid topology change in vehicular ad hoc network （VANET} is common due to the inherent high mobility nodes and unpredictable environments in VANET. In order to ensure efficient packet transmission, nodes in VANET should react adaptively to topology change in VANET. In this paper, we present a new heuristic and adaptive fuzzy logic scheme （HaFL） , which adapts the contention window size and transmission power according to network and traffic conditions. The current existing schemes in VANET utilize only a single parameter to optimize the contention window and transmission power without eonsideration on the effects of interference as one of the main factors in VANET transmission degradation. In VANET, packet loss can occur at different stages of transmission due to interference or due to elapsed time. In the proposed HaFL, fuzzy logic is used to adaptively optimize the contention window size based on three parameters namely collision rate, SINR and queue overflow which represent packet drop at different stages of transmission. Transmission power which is usually a static parameter is also optimized with consideration on the effects of VANET interference in the proposed HaFL. The performance of the proposed HaFL is evaluated in Vehicles in Network Simulation with road traffic simulator, Simulation of Urban mobility. Simulation results show that the proposed HaFL demonstrates adaptability with improved throughput, low end - to - end delay and higher packet success rate in comparison with the default IEEE802.1 I p and existing schemes.