Limitations of MIMO and Multi-User Access for OFDM Radar in Automotive Applications

This paper highlights the parameterization limitations of MIMO OFDM radar especially in multi-user scenarios. First the parameter dependencies are depicted and the resulting limitations are derived. Based on this it is demonstrated how the basic scheme can be modified to generate orthogonal channels, either for multiple transmitters of the same system or for different users to operate in an almost interference free state. The focus is on automotive applications for highly automated driving (HAD) that require both, high range and velocity resolution as well as fail save operation in scenarios with multiple users. Additionally, the limitations of Compressed Sensing in combination with OFDM radar to overcome some of the previous limitations are analyzed. Analytical studies as well as simulations have been done to depict the mentioned limitations.