Introduction

Connected vehicle (CV) technologies enable a wide range of transportation applications, safety, mobility, and infotainment. While holding tremendous promise, the success of these CV-enabled applications relies heavily on the quality of the underlying information flow [1]. NetSim is a simulation tool designed to model, simulate and analyze this information flow. The vehicular communication architecture in NetSim is based on a combination of the IEEE 1609 standard and IEEE 802.11p standard. The 802.11p standard defines the PHY and MAC layers while IEEE 1609 defines the upper layers.

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Figure-1: NetSim-SUMO interfacing for VANET simulation. Top left is a SUMO screen shot while bottom right is a NetSim screen shot.

NetSim’s VANET library features:

  • IEEE 802.11p PHY operating in the 5.9 GHz band with a channel bandwidth of 10 MHz. 802.11p is an adaptation of the widely used IEEE 802.11a standard previously used in Wi-Fi systems.

  • Radio propagation in the PHY layer covering various pathloss, shadowing, and fading models.

  • IEEE 802.11p MAC layer. Stations communicate directly outside the context of a BSS.

  • IEEE 1609-2, which defines security services for application messages and management messages in WAVE.

  • IEEE 1609-3, which defines connection set up and management of WAVE compliant devices.

  • IEEE 1609-4, which enables upper layer operational aspects across multiple channels without knowledge of PHY layer parameters.

  • DSRC SAE J2735

  • BSM packets that are transmitted using WSMP

  • A spontaneous Ad hoc network formation between the VANET nodes; layer-3 IP routing can be through DSR, AODV, OLSR or ZRP for non-BSM packets

  • Vehicular mobility using in-built mobility models or by interfacing with SUMO software

  • Interfacing between SUMO & NetSim via Traffic control interface (TraCI). Automatic import of road network and vehicle mobility from SUMO

  • Wide range of output metrics including Delay, Throughput, Error, Retransmission, etc.

  • Protocol source C code is provided along with NetSim software

In VANETs, Vehicles and roadside units (RSUs) are the primary communicating nodes, providing each other with (i) Safety information using BSM application and (ii) Infotainment applications. Both types of nodes are Dedicated Short-Range Communications (DSRC) devices. The RSU is a WAVE device usually fixed along the roadside or in dedicated locations such as at junctions or near parking spaces. In NetSim, users can model network traffic flows:

  • Between two or more Vehicles, known as V2V

  • From vehicles to RSUs (infrastructure), known as V2I

  • Between two or more RSUs

  • From vehicles or RSUs to remote servers, by connecting RSUs in backhaul to a wired network consisting of switches, routers, and servers for end-to-end simulation.