Vehicular communications will foster mobility services and enable mass adoption of future autonomous vehicles, interchanging huge amount of data acquired from vehicles’ sensors. 3GPP Release 14 presents the first standard for supporting V2X in LTE. Several enhancements are introduced, including a new arrangement of the physical resource grid, where subchannels are the minimum resource unit instead of Resource Blocks. The resource grid is defined by several design parameters, some of them with constraints imposed by 3GPP specifications, that affect the maximum message transmission rate and efficiency of the system. Moreover, the optimum choice of these parameters is closely linked to message length, which is another variable parameter. This paper provides an analysis of the relationship between these design parameters (Resource Block per Subchannel, Transport Block Size Index, and coding rate), message size, and the system’s maximum capacity and efficiency. In doing so, we do not consider channel reuse or radio transmission characteristics because the focus of this paper is trying to find the resource grid design parameters that optimize system capacity, which is a very important aspect to consider by V2X operators.

中文翻译：

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了解车载网络中PC5资源网格设计对LTE-V2X容量和效率的影响

车辆通信将促进出行服务，并使未来的自动驾驶汽车得到广泛采用，从而交换从车辆传感器获取的大量数据。3GPP版本14提出了在LTE中支持V2X的第一个标准。引入了一些增强功能，包括物理资源网格的新布置，其中子信道是最小资源单位而不是资源块。资源网格由几个设计参数定义，其中一些参数受3GPP规范施加的约束，这些参数会影响最大消息传输速率和系统效率。此外，这些参数的最佳选择与消息长度密切相关，消息长度是另一个可变参数。本文提供了这些设计参数（每个子通道的资源块，传输块大小索引和编码率），消息大小以及系统的最大容量和效率。这样做时，我们不考虑信道重用或无线电传输特性，因为本文的重点是尝试找到优化系统容量的资源网格设计参数，这是V2X运营商要考虑的非常重要的方面。