Multi-channel operations, coexistence and spectrum sharing for vehicular communications

DSRC has been allocated (three in EU, seven in US) dedicated channels at 5.9 GHz for vehicular communications. Although resource allocations on the common control channel (CCH) reserved for safety-related applications have been well investigated, efficient usage of the other SCHs is less developed. With new ITS safety-related applications appearing, such as autonomous driving or truck platooning, as well as the expected coexistence between ITS and non-ITS technologies for smart mobility applications, operating on multiple channels and efficiently sharing the ITS spectrum become critical. First, multi-channel operations aim at mitigating the communication load on specific channels by offloading part of traffic to alternate channels. Second, multi-channel operations aim at providing mechanisms to dynamically change channels and fit to the service requirements as function of external interferences or to varying traffic conditions. In this chapter, we describe the regulations and mechanisms for ITS multi-channel operation and coexistence in the US and in the EU. We first provide an overview of the frequency allocations and access restrictions for ITS, and then describe the protocols available in standards and R&D for multi-channel operations.