Broadcast Channel Framework and Beyond for Dedicated Waveform Synthesis and Performance Assessment of Integrated Sensing and Communications

Communications and sensing were developed and designed independently in the last several decades, each with vastly different design objectives. Specifically, communications aim to deliver information data to destination(s) in the forward propagation of electromagnetic (EM) waves, while sensing is to extract information of the environment from the backward propagation of EM waves upon reflections of significant targets.

In the next generation of wireless networks, it is desirable to integrate both tasks of communications and sensing under a unified framework, which ensures that the EM waveforms of both communications and sensing share the same spectrum and power, thus substantially improving the resource utilization of wireless systems and lowering the implementation cost with shared hardware architecture. This technology is called integrated sensing and communications (ISAC).

The major challenge of ISAC is how to interleave different tasks of communications and sensing in the same signal, transmitter and receiver designs. The proposed approach is tested in both software and hardware, and then employed in the context of urban air mobility (UAM). The success of this project will discover new fundamental understandings of ISAC, lead to new ISAC designs with substantially performance improvement over the state of the art, and lower the complexity and cost of numerous ISAC applications, including urban air mobility, autonomous driving, smart agriculture, and Internet of Things in general.

The key approach of the project is to consider the ISAC transmitter as broadcasting information to a genuine communication user and a virtual sensing user, and thus seamlessly integrate both tasks in the same signal using various techniques of the information-theoretic broadcast channel framework. The following research tasks are carried out accordingly: Task 1.

Identifying and quantifying the fundamental trade-offs between communications and sensing; Task 2. Adopting an information-theoretic broadcast channel framework for efficient designs and implementation, such as dirty paper coding, coded-division multiple access (CDMA), windowed phase shift keying (PSK) orthogonal frequency division multiple access (OFDM).

Task 3. Collaboration between communications and sensing that harvests the gains of active feedback across the control plans of ICAS, and results in a joint design that is greater than the sum of its parts. Task 4.

Software and hardware testbed and experiments in the context of UAM. This multidisciplinary project develops new fundamental analysis, generic first principle of waveform designs, and concrete algorithms and protocols, which would directly impact the research paradigm of ISAC. The results of this project are incorporated into graduate-level course curricula, and the activities are used to broaden participation of high-school and undergraduate students through pre-college programs and Purdue Vertically Integrated Projects, a campus-wide undergraduate research course, respectively, including providing mentorship and career consultation for participating high-school and college students.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.