Understanding the impact of the PC5 resource grid design on the capacity and efficiency of LTE-V2X in vehicular networks

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.This work has been supported in part by the ERDF and the Spanish Government through projects TEC2016-79988-P and TEC2016-76795-C6-2-R; by the Spanish Ministerio de Industria, Energía y Turismo and CELLNEX through project TSI-100102-2015-13 V2XArch; and by the ERDF and Secretaria d’Universitats i Recerca de la Generalitat de Catalunya through projects 2017-SGR-00376 and FEM IoT 001-P- 001662. Additionally, part of this work has been produced in the master’s thesis of Leandro Miguel Lopez [22] that he carried out at the Universitat Politècnica de Catalunya.Peer ReviewedPostprint (published version