| We develop the notion of orthogonal frequency division multiple access (OFDMA) to enable a radar to execute multiple tasks simultaneously. OFDMA, like the betterknown orthogonal frequency division multiplexing (OFDM) radar, encodes information on subcarriers in the frequency domain. However, in an OFDMA-based radar, the information can correspond to independent tasks to be executed simultaneously; of specific interest here, as proof of concept, is to partition the OFDMA subcarriers to detect two targets simultaneously. Designing a broadband OFDMA signal is an efficient and resourceful way to achieve this, since, as we propose, the frequency domain information for each subcarrier can correspond to each task. Applied to a high-frequency surface wave radar, in presence of a realistic ocean clutter, our results show that the OFDMA framework allows us to combine adaptive transmit beampatterns with task execution. We also develop a subcarrier allocation scheme to maximize the probability of detection. |
