JCAS for 6G: Features, Benefits and Limitations

Joint Communications and Sensing (JCAS) technology enables wireless network to perform two functions at a time that is transmitting data (i.e. communication) and understanding physical environment (i.e. sensing). It is also known by ISAC (Integrated Sensing and Communication). It has been envisioned for future 6G wireless release.

We have seen with few examples around us that, these functions are separate. For example, our phone communicates using cellular frequency signals while our car uses radar or lidar to sense obstacles. JCAS merges both of these functionalities together with single set of hardware and signal radio signal.

The core idea is that the radio waves sent out for communication inevitably reflect off objects, people, and the environment. These reflections, or echoes, which are often treated as noise or interference in a pure communication system, contain a wealth of information. A JCAS enabled network is designed to intelligently transmit communication signals and then meticulously analyze the returning echoes to extract sensing data, such as an object’s location, speed and shape. JCAS creates real time “digital map” or “digital twin” of its surroundings.

Advantages of JCAS

Following are some of the benefits of Joint Communications and Sensing (JCAS).

1. By using the same frequency band for both functions, JCAS eliminates the need for separate, dedicated spectrum for sensing (like radar bands), making more efficient use of this scarce resource.
2. Accurate Location Services: JCAS can provide highly accurate, real time positioning information, far superior to today’s GPS, especially in indoor or dense urban environments where satellite signals are weak.
3. The network can sense its environment to predict and avoid link blockages.
4. It reduces the need for deploying two separate infrastructures (one for communication, one for sensing). This leads to lower hardware costs.
5. Due to single hardware unit, it avoids powering two separate units which helps in overall reduction of energy consumption.

Disadvantages of Joint Communications and Sensing (JCAS)

Despite its immense potential, it faces several Following are some of the limitations or challenges of JCAS.

1. Balancing two specific system requirements of two different applications into one is challlenging. For example, for communication to user, system needs to focus narrow beam of energy towards user. For sensing, radar needs to beam signal is larger wide area.

2. As we know sensing task requires signal waveforms which are good to measure distance/velocity while communication requires waveforms that carry huge amount of data. It is challenging to design a unified waveform which performs both the tasks (sensing and transmission) well or perform dynamic switching between two different waveforms.

3. The network must intelligently decide how to allocate its resources (e.g., power, bandwidth, antenna beams) between communication and sensing. They need to be managed dynamically based on the application’s needs.

4. Extracting precise sensing information from communication signals that are also carrying random data is a highly complex signal processing task. It requires sophisticated AI/ML algorithms to build real time environment details.

5. Security & Privacy Concerns : A network that can constantly sense its surroundings raises significant privacy issues. The ability to track people’s movements and activities without their explicit and continuous consent must be addressed with robust security protocols and privacy-preserving regulations.

Conclusion: As 6G networks evolve, JCAS stands out as a pivotal technology that elevates wireless systems from pure connectivity to integrated awareness.