Over the last few decades, the attraction towards Vehicular Ad Hoc Network (VANET) has engrossed huge investigation, to upgrade road safety and entertainment for the traveler, by imparting real time information among vehicles. In order to accomplish this, network layer has attained significant attention; therefore, abundant routing protocols have been proposed. In VANET, frequent movement and rapid topological variation lead to repeated link breakage, causing loss in packet and delay. As compared to other VANET routing protocols proposed so far, location based routing methods provide one of the best solutions, by not relying on pre destination route entries. However, location based routing protocol also encounters several challenges such as local optimum problem, inaccurate positioning, optimum forwarder selection and broadcasting overheads. This paper analyzes these challenges in brief, and critically compares the existing solutions proposed so far. It also presents brief description of emerging WAVE+LTE based technology along with some viable direction for future improvement related to location based routing protocols.

在过去的几十年中，对车载自组织网络（VANET）的吸引力引起了广泛的调查，通过在车辆之间传递实时信息来提高旅行者的道路安全性和娱乐性。为了做到这一点，网络层受到了极大的关注。因此，已经提出了丰富的路由协议。在VANET中，频繁的移动和快速的拓扑变化导致重复的链路断开，从而导致数据包丢失和延迟。与到目前为止提出的其他VANET路由协议相比，基于位置的路由方法通过不依赖于目的地路由条目来提供最佳解决方案之一。但是，基于位置的路由协议也遇到了一些挑战，例如局部最优问题，定位不正确，最优转发器选择和广播开销。本文简要分析了这些挑战，并严格地比较了迄今为止提出的现有解决方案。它还简要介绍了新兴的基于WAVE + LTE的技术，以及与基于位置的路由协议相关的未来改进的一些可行方向。