Norval Hybrid DES-based Vehicular Network Simulator with Multichannel Operations
A vehicular network enables vehicles to communicate between each in order to improve road safety and efficiency. Within a network, communications can potentially alter vehicular mobility, and conversely that mobility could potentially influence vehicular communications. Therefore, a vehicular network simulation environment is needed that can accurately model interactions between vehicular mobility and network protocols. In my research, a novel vehicular network simulation environment designed using discrete-event programming is presented. The proposed simulation environment, VANET Toolbox, is a bit-accurate, discrete-event simulator that integrates vehicular mobility operations with message generation functions in the APP layer DES module. The MAC layer DES module supports single channel and multichannel operations, both of which are equipped with Enhanced Distributed Channel Access (EDCA) schemes to ensure quality of service (QoS) by granting priorities to messages. The PHY layer DES module supports bit-level processing, i.e., the transmitted data unit is on bits and it is the same as the real communication between radio hardware. Compared with packet-based simulator such as NS-3, our proposed simulator is more realistic and accurate.
The computational costs of the proposed simulation environment are evaluated in terms of events quantities. The bit-level processing is compared with packet-level processing to show its advantages on channel tracking (CT). The EDCA is evaluated in the single channel scenario and compared with the traditional Carrier-sensing multiple access (CSMA) scheme, the simulations prove that data with different priorities can coexist in the same channel and EDCA is effective to guarantee the QoS of data with higher priority compared with CSMA.
The multichannel operation is also analyzed with details. The multichannel alternation and coordination may cause packet drop and longer latency to some extent. However, under heavy traffic, multichannel performs better than single. From the perspective of safety-related messages, multichannel operation is able to isolate the interference from the non-safety messages in order to achieve a better packet delivery rate and latency. On the other hand, the non-safety messages can achieve high throughput with reasonable latency from multichannel under heavy load traffic scenario. Last but not least, a new SCH/AC scheme is proposed to help service providers reserve service channels (SCHs) in a more efficient way compared with the random-pick mechanism in the standards.
Prof. Alex Wyglinski
ECE Department, WPI
Prof. Andrew Clark
ECE Department, WPI
Prof. Kaushik Chowdhury
ECE Department, Northeastern University (NEU)