Automotive 24 GHz pulse radar extended by a DQPSK communication channel

An increasing number of cars is equipped with radar sensors for different applications observing the car environment. In order to improve the reliability of a single sensor and to gain additional information e.g. by triangulation, data from different sensors can be combined. One step further is to exchange sensor data between neighbouring cars by a data link to continuously transmit vehicle safety relevant sensor information. For this purpose it is necessary to establish an intervehicle communication (IVC) link. This task can be realized by independent communications links. A different attractive approach would be to partially use the hardware and the frequency spectrum of the existing radar sensors. This was the impulse to extend a pulse radar at a center frequency of 24.125GHz by a communication transceiver in the same frequency band. The communication band, which is small compared to the radar spectrum, is placed in a range with low radar power spectral density. The pulse radar principle was chosen, because it is most common and key components, respectively RF-Frontends, are already available. The principle also provides short measurement times and high dynamic range. In the following the basic concept of the built prototypes and the signal processing of the radar and transceiver on FPGAs are described. The suitability of the system concept is discussed based on measurements and simulations.