Abstract
Mobile data traffic continues to increase rapidly due to the widespread use of smart devices and connected vehicles. This growth places enormous stress on wireless networks, particularly in terms of maintaining quality of service and managing handover (HO) processes. In this context, vehicle-to-vehicle (V2V) communication has emerged as a critical component of next-generation intelligent transportation systems. However, ensuring seamless mobility remains a major challenge, especially in high-speed vehicular environments where frequent HOs occur. This paper provides a comprehensive review of HO decision techniques tailored to V2V communications in 6 G networks. We analyze the core challenges such as mobility management, security, interference, and service continuity and evaluate state-of-the-art HO algorithms including Bayesian regression, fuzzy logic, machine learning, and software-defined networking approaches. Furthermore, we highlight the unique opportunities offered by 6 G technologies, such as ultra-reliable low-latency communication, terahertz spectrum, and AI-native networking, to improve the stability, efficiency, and reliability of V2V HO management. Finally, we present insights into open research challenges and future directions, emphasizing how advanced HO mechanisms can support the requirements of autonomous driving and intelligent transportation systems.