MIMO radar: Time division multiplexing vs. code division multiplexing

Multiple-Input-Multiple-Output (MIMO) radar systems with colocated transmit (Tx) and receive (Rx) antennas can achieve a high performance in direction of arrival (DOA) estimation due to their larger virtual aperture compared to a corresponding Single-Input-Multiple-Output (SIMO) radar. A MIMO radar needs the use of a multiplexing technique. We consider code division multiplexing (CDM) and time division multiplexing (TDM) MIMO radars. CDM offers more degrees of freedom than TDM, which results in a more flexible design of the transmission sequences. On the other hand, a TDM MIMO radar requires less complex hardware. This is especially important for radars applied to automobiles, since they have to be produced at low cost. We compare the performance of DOA estimation of TDM MIMO radars to CDM MIMO radars. We show that for a limited total transmission power the TDM MIMO radar can achieve the same performance in DOA estimation as a CDM MIMO radar.