Scalable Modulation-based Multi-Service Multiplexing Transmission for Vehicular Communications

The explosion of large volume services has posed great challenges on the limited spectrum resource of vehicular communications, which are further aggravated owing to the low spectral efficiency (SE) caused by high mobility of vehicles. Considering the services with different quality of service (QoS) requirements, the multi-service multiplexing transmission method can be employed to improve the SE of vehicular communications. In this paper, an adaptive multiplexing transmission scheme based on scalable modulation (S-Mod) is proposed. Considering two typical types of services for vehicular communications, a series of S-Mod constellation diagrams are designed according to their QoS requirements. Then an adaptive S-Mod transmission strategy based on the designed S-Mod constellation diagrams is proposed. The simulation results show that, compared with the traditional adaptive Mary quadrature amplitude modulation (M-QAM) transmission scheme, the proposed adaptive S-Mod scheme can improve the SE up to 19%.