Integrated Sensing and Comms (ISAC) with MATLAB and SDR

MATLAB generates a custom OFDM waveform that includes pilot signals that are used to calculate time-varying channel estimates. MATLAB also creates a synthetic bistatic sensing scenario, where a transmitted waveform reflects off a target to a receiver. A USRP software-defined radio (SDR) is used to transmit the OFDM signal over the air and to receive it. Once the radio receives the signal, its FPGA emulates a radar target by imposing latency, path loss, and Doppler on the signal. It also emulates a two-path channel, with one line of sight component, and one reflected component. The radio then retransmits the two-path signal over the air, then receives that retransmitted signal and sends it to MATLAB for both communications and radar processing. The communications receiver performs synchronization in frequency, phase, and time to convert the impaired OFDM waveform into bits. It also performs channel estimation with the pilot signals, whose values are known by the receiver. Those channel estimates are then concatenated in time to create the equivalent of a radar data cube. The “fast time” component of the data cube is used to calculate the bistatic range of the target to the receiver, and the “slow time” component is used to calculate the radial velocity of the target from the receiver. A scenario viewer shows the trajectory of the target in two-dimensional cartesian coordinates, and a range-Doppler plot shows the results of the data cube processing. A constellation diagram also shows a single carrier QPSK constellation after OFDM demodulation, and a bit error rate meter shows the quantitative link performance of the transceiver.