MAJoRCom: A Dual-Function Radar Communication System Using Index Modulation (1909.04223v1)

Abstract: Dual-function radar communication (DFRC) systems implement both sensing and communication using the same hardware. Such schemes are often more efficient in terms of size, power, and cost, over using distinct radar and communication systems. Since these functionalities share resources such as spectrum, power, and antennas, DFRC methods typically entail some degradation in both radar and communication performance. In this work we propose a DFRC scheme based on the carrier agile phased array radar (CAESAR), which combines frequency and spatial agility. The proposed DFRC system, referred to as multi-carrier agile joint radar communication (MAJoRCom), exploits the inherent spatial and spectral randomness of CAESAR to convey digital messages in the form of index modulation. The resulting communication scheme naturally coexists with the radar functionality, and thus does not come at the cost of reduced radar performance. We analyze the performance of MAJoRCom, quantifying its achievable bit rate. In addition, we develop a low complexity decoder and a codebook design approach, which simplify the recovery of the communicated bits. Our numerical results demonstrate that MAJoRCom is capable of achieving a bit rate which is comparable to utilizing independent communication modules without affecting the radar performance, and that our proposed low-complexity decoder allows the receiver to reliably recover the transmitted symbols with an affordable computational burden.

• The paper introduces MAJoRCom, a Dual-Function Radar Communication (DFRC) system integrating communication into radar using frequency and spatial index modulation.
• MAJoRCom is built upon the Carrier Agile Phased Array Radar (CAESAR) framework, leveraging its agility to embed communication data without degrading radar performance.
• The system demonstrates competitive communication capacity with a proposed low-complexity decoder, holding practical implications for fields like autonomous driving and aerospace.

An Essay on MAJoRCom: A Dual-Function Radar Communication System Using Index Modulation

The ever-growing demand for integrated systems capable of both radar sensing and communication has brought the concept of Dual-Function Radar Communication (DFRC) systems to the forefront. The paper on MAJoRCom by Huang et al. introduces an innovative approach to DFRC systems, utilizing a hybrid modulation technique that capitalizes on frequency and spatial index modulation. This essay provides a detailed appraisal of the concepts, methodologies, results, and implications presented in the paper.

Overview of MAJoRCom System

MAJoRCom is constructed upon the Carrier Agile Phased Array Radar (CAESAR) framework, extending its utility beyond traditional radar to embody communication capabilities. CAESAR is a radar scheme noted for its agility; it dynamically selects carrier frequencies and allocates these among antennas in a manner designed to exploit both spectral and spatial variation. MAJoRCom leverages this inherent variability to form a communication scheme without degrading radar performance, achieving a natural coexistence of radar and communication functions.

Technical Contributions

1. Index Modulation Integration: At the core of MAJoRCom's design is the embedding of digital information using index modulation. The system divides the modulation process into two key stages: frequency index modulation and spatial index modulation. By selecting combinations of carrier frequencies and antenna allocations, additional information can be transmitted.
2. Performance Analysis: The paper presents a detailed analytical paper of MAJoRCom's communication capacity. Notably, the achievable bit rate is shown to be competitive with dedicated communication systems, under the constraint that radar performance is untouched.
3. Low Complexity Decoding: A significant hurdle in index modulated systems is the decoding complexity. The authors address this by proposing a low complexity decoder that iteratively refines its estimates of frequency and spatial indices, significantly reducing receiver-side computational load.
4. Codebook Design: Recognizing the challenge in receiver-side processing, a systematic approach to codebook design is presented. By reducing the codebook size, the authors facilitate easier decoding, balancing complexity with achievable communication rates.

Results and Implications

The numerical simulations substantiate the potential of MAJoRCom to deliver effective communication performance without imposing performance trade-offs on radar operations. The system achieves an appropriately high bit error rate under realistic channel conditions, as verified through extensive simulations.

The practical implications of this work are pronounced in fields such as autonomous driving, aerospace, and military applications, where the seamless integration of communication into radar systems can lead to reduced hardware costs while maintaining system fidelity and performance.

Future Directions

The integration of index modulation into DFRC systems opens several avenues for future research and enhancement. One prospect is the exploration of adaptive methods for index selection to further optimize communication robustness under varying channel conditions. Furthermore, extending these concepts to wider band systems and investigating the interplay between radar waveform diversity and communication bit rate can yield richer insights into the optimization of integrated radar-communication systems.

Conclusion

In conclusion, MAJoRCom represents a solid step toward the realization of efficient, integrated DFRC systems. Its emphasis on leveraging existing radar architecture for communication serves as a haLLMark for how similar systems can be designed without the conventional trade-offs involved in resource sharing. The analytical rigor and numerical validation presented provide both clarity and confidence in the system's capabilities and potential impact.