[Paper Review] Coexistence between Communication and Radar Systems - A Survey

Mina Labib, Vuk Marojevic+3 more|arXiv (Cornell University)|Sep 25, 2017

Radar Systems and Signal Processing16 references3 citations

TL;DR

This survey presents a comprehensive analysis of spectrum sharing techniques enabling coexistence between radar and wireless communication systems, focusing on cognitive radio, waveform design, and joint optimization methods. It demonstrates that coexistence is feasible through interference management and adaptive resource allocation, with key advances in MIMO radar and OFDM-based systems preserving radar performance while enhancing spectrum efficiency.

ABSTRACT

Data traffic demand in cellular networks has been tremendously growing and has led to creating congested RF environment. Accordingly, innovative approaches for spectrum sharing have been proposed and implemented to accommodate several systems within the same frequency band. Spectrum sharing between radar and communication systems is one of the important research and development areas. In this paper, we present the fundamental spectrum sharing concepts and technologies, then we provide an updated and comprehensive survey of spectrum sharing techniques that have been developed to enable some of the wireless communication systems to coexist in the same band as radar systems.

Motivation & Objective

• Address the growing RF spectrum congestion caused by rising data traffic in cellular networks.
• Investigate spectrum sharing between radar and communication systems to improve spectral efficiency.
• Survey and analyze advanced techniques such as cognitive radio, waveform design, and joint optimization for coexistence.
• Evaluate the feasibility of coexistence without degrading radar system performance.
• Provide a comprehensive overview of current regulations and radar systems in shared bands like CBRS and U-NII.

Proposed method

• Categorize radar systems in shared bands (e.g., CBRS, U-NII) and analyze their regulatory frameworks.
• Survey spectrum sharing techniques including cognitive radio, spectrum sensing, and dynamic access protocols.
• Examine interference mitigation via zero-forcing precoding and null-space projection in MIMO radar-communication systems.
• Propose waveform design strategies using SNR-based waterfilling and mutual information criteria to minimize interference.
• Implement joint optimization of radar and communication systems using multi-objective optimization and OFDM subcarrier allocation.
• Introduce cooperative transmit and receive beamforming to minimize co-channel interference in MIMO setups.

Experimental results

Research questions

• RQ1 How can radar and communication systems coexist in the same frequency band without causing harmful interference?
• RQ2 What are the key technical challenges in enabling spectrum sharing between legacy radar systems and modern communication networks?
• RQ3 To what extent can cognitive radio and dynamic spectrum access improve spectral efficiency in shared bands?
• RQ4 How can MIMO radar and multi-user communication systems be jointly optimized for interference mitigation?
• RQ5 What role do waveform design and beamforming play in enabling coexistence while preserving radar detection performance?

Key findings

• Spectrum sharing between radar and communication systems is feasible, especially when communication systems are adapted to avoid interference.
• Zero-forcing precoding and null-space projection techniques effectively suppress interference at the communication receiver, assuming perfect channel state information.
• Waveform design based on SNR waterfilling and mutual information criteria reduces interference to coexisting communication systems while maintaining radar performance.
• OFDM-based joint design allows subcarrier allocation to simultaneously maximize radar detection and communication capacity.
• Joint optimization of transmit and receive beams in MIMO systems significantly reduces co-channel interference and improves signal-to-interference-plus-noise ratio.
• Multimodal radar systems that adapt bandwidth dynamically enable efficient spectrum sharing by reserving bandwidth for communications during low-activity radar periods.