Vehicular communication networks represent both an opportunity and a challenge for providing smart mobility services by using a hybrid solution that relies on cellular connectivity and short range communications. The evaluation of this kind of network is overwhelmingly carried out in the present literature with simulations. However, the degree of realism of the results obtained is limited because simulations simplify real world interactions too much in many cases. In this article, we define an outdoor testbed to evaluate the performance of short range vehicular communications by using real world personal portable devices (smartphones, tablets, and laptops), two different PHY standards (IEEE 802.11g and IEEE 802.11a), and vehicles. Our test results on the 2.4 GHz band show that smartphones can be used to communicate vehicles within a range up to 75 m, while tablets can attain up to 125 m in mobility conditions. Moreover, we observe that vehicles equipped with laptops exchange multimedia information with nodes located further than 150 m. The communications on the 5 GHz band achieved an effective transmission range of up to 100 m. This, together with the optimization of the protocols used, could take our commodity lightweight devices to a new realm of use in the next generation of ad hoc mobility communications for moving through the city.

翻译：车载通信网络通过结合蜂窝网络与短距离通信的混合解决方案，为智能出行服务提供了机遇与挑战。现有文献中对此类网络的评估主要依赖仿真手段，但由于仿真过程过度简化现实交互场景，所得结果的实际参考价值有限。本文构建了一套户外测试平台，通过采用真实世界的个人便携设备（智能手机、平板电脑及笔记本电脑）、两种不同的物理层标准（IEEE 802.11g与IEEE 802.11a）以及实际车辆，对短距离车载通信性能进行评估。在2.4 GHz频段的测试结果表明：智能手机可实现最远75米范围内的车辆间通信，平板电脑在移动环境下通信距离可达125米。此外，配备笔记本电脑的车辆能与150米外的节点进行多媒体信息交换。在5 GHz频段实验中，有效传输距离可达100米。结合协议优化策略，这些轻量级商用设备有望在下一代城市移动自组织通信系统中开辟全新的应用领域。