A Dual-Function Massive MIMO Uplink OFDM Communication and Radar Architecture

Abstract

This paper proposes a joint uplink massive multiple-input-multiple-output (MIMO) communication and orthogonal frequency-division multiplexing (OFDM) radar sensing architecture. Specifically, uplink communication and short-range radar sensing are considered, where the user equipments (UEs) transmit data to the base-station (BS), which simultaneously receives radar returns from the targets over the same subcarriers. Hence, the signals received at each BS antenna include radar returns and communication signals to be processed for extracting the sensing and communication data. The separation and detection of such signals are achieved by utilizing the channel diversity between the UEs and the targets. To this end, the UEs' signals are first detected and demodulated, and then subtracted from the received signal to acquire the radar returns. Symbol-based radar processing is then employed, as it provides substantial processing gains, and its detection performance is independent of the transmitted radar waveform. Furthermore, self-interference-due to the simultaneous operation of transmit and receive antennas-is taken into account. The communication capacity and normalized error of the radar-target channel estimation are mathematically analyzed, and the trade-off between the communication capacity and radar detection performance is demonstrated in terms of the power output of the communication and radar sub-systems, as well as the signal-to-noise ratio.

Joint Communication and Sensing: Models and Potential of Using MIMO

“…Recently, the authors further detailed the UL receiving procedure, where the user messages and target echoes are successively processed using the SIC. Analytical works were conducted under the consideration of imperfect CSI and selfinterference and the trade-off relationship of the achievable rate and radar detection performance was revealed [99]. Liu et al proposed two precoding schemes to compare the performance of separate and shared deployments.…”

Full-Duplex Communication for ISAC: Joint Beamforming and Power Optimization

“…The second scenario in Fig. 1(b) considers integrating sensing with uplink communication [18], [19], where the BS can be regarded as a radar transceiver and a communication receiver. The authors of [18] developed an advanced receiver architecture for uplink ISAC, which separates the radar echo and communication signals by performing interference cancellation techniques.…”

“…1(b) considers integrating sensing with uplink communication [18], [19], where the BS can be regarded as a radar transceiver and a communication receiver. The authors of [18] developed an advanced receiver architecture for uplink ISAC, which separates the radar echo and communication signals by performing interference cancellation techniques. Sensing-assisted physical-layer security transmission was investigated in [19], where the BS transmits a downlink radar signal to localize and jam a potential aerial eavesdropper while receiving the uplink communication signal.…”

“…In the aforementioned works [14]- [19], the radar receiver operates simultaneously while transmitting, i.e., in a fullduplex (FD) manner, especially for short-range radar. Selfinterference (SI), which is a critical issue in FD operation, is considered to be significantly suppressed by installing spatially widely-separated transmit and receive antennas and employing advanced SI cancellation techniques [5], [18], [20], [21]. Particularly, in an FD ISAC system, the SI cancellation should be performed for the direct coupling between the transceiver antennas only, while target reflections should be preserved [20].…”

“…Specifically, the algorithms designed in [14]- [17] do not incorporate the impact of uplink communication. In [18], [19], only a pure downlink sensing signal is sent and the uplink transmit power is fixed, without considering the possibility of downlink communication nor designing the uplink transmission.…”