5G signal design for road surveillance

This paper proposes a novel road surveillance system for vehicular safety applications to improve the situation awareness of road users. The proposed surveillance system uses signals from vehicular communications infrastructure as illuminators of opportunity. Due to high accuracy requirements of safety applications, the optimal signal design for the surveillance system is discussed in detail. In this regard, the main design criteria is the accuracy of delay and Doppler estimation. Therefore, the Cramer-Rao lower bounds for the joint estimation of delay and Doppler are derived, which are used to evaluate the estimation performance. Together with a detailed geometrical discussion of a bistatic link, the constraints for the signal design are derived. Adopting a multi-carrier 5G localization waveform, this study parametrizes a flexible 5G signal for road surveillance. For an urban environment a parameter set is derived, which is shown to fully satisfy the delay estimation accuracy requirements. Furthermore, the estimation capabilities of bistatic links are evaluated geometrically, clearly identifying the areas allowing valid joint parameter estimation.