MIMO Radar Subcarrier Segmentation for DFRC
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Solution Overview
Problem
Existing dual-function radar-communication systems face limitations in fully exploiting bandwidth for communication purposes due to exclusive assignment of subcarriers in MIMO DFRC systems, which restricts their ability to achieve high sensing performance and communication rate simultaneously.
Innovation Solution
A MIMO radar system is configured with only a small number of active antennas in each channel use, using OFDM waveforms where subcarriers are divided into shared and private groups, allowing for high angular resolution and communication rate through generalized spatial modulation and sparse signal recovery methods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If subcarriers are assigned to transmit antennas in an exclusive fashion in MIMO DFRC systems, then each antenna has dedicated resources for sensing, but the system's ability to fully exploit the available bandwidth for communication purposes is limited
Solution Approach 1:
The patent segments the subcarriers into two distinct groups: shared subcarriers that are exclusively assigned to specific transmit antennas for sensing purposes, and common subcarriers that are shared by all active transmit antennas for communication purposes. This segmentation allows the system to simultaneously optimize sensing performance through dedicated subcarriers while maximizing communication rate through shared subcarriers that fully exploit the available bandwidth.
2Measurement precision
If a large number of antennas are used in MIMO radar systems, then high angle resolution is achieved, but hardware costs increase
Solution Approach 1:
The patent introduces a new dimension for achieving high angle resolution by utilizing the frequency domain through OFDM waveforms. Instead of increasing the number of physical antennas in the spatial domain, the system uses multiple subcarriers to synthesize a virtual array with larger aperture. The shared subcarriers are used by multiple antennas simultaneously, creating virtual antenna elements that achieve fine angle resolution without requiring a proportional increase in physical hardware.
3Device complexity
If only a small number of antennas are active in each channel use, then hardware complexity is reduced, but the ability to detect multiple targets simultaneously is limited
Solution Approach 1:
The patent makes the shared subcarriers universal resources that can be simultaneously accessed by all active transmit antennas. This multi-functionality allows a small number of physical antennas to effectively serve multiple targets at the same time, as each antenna can transmit on the shared subcarriers with unique spatial signatures. The system achieves enhanced target detection capability through the combination of spatial diversity from multiple antennas and frequency diversity from shared subcarriers, without requiring a large number of simultaneously active antennas.
Data Source
AI summary
Various embodiments comprise systems, methods, architectures, mechanisms and apparatus providing a dual-function radar communication (DFRC) system a multiple-input multiple-output (MIMO) radar is configured to have only a small number of its antennas active in each channel use. Probing waveforms are of an orthogonal frequency division multiplexing (OFDM) type. OFDM carriers are divided into two groups, one group that is used by the active antennas in a shared fashion, and another group where each subcarrier is assigned to an active antenna in an exclusive fashion (e.g., private subcarriers). Target estimation is carried out based on the received and transmitted symbols. The system communicates information via the transmitted OFDM data symbols and the pattern of active antennas in a generalized spatial modulation (GSM) fashion. A multi-antenna communication receiver can identify the indices of active antennas via sparse signal recovery methods. The private subcarriers may be used to synthesize a virtual array for high angular resolution, and also for improved estimation on the active antenna indices.