As the telecom industry moves toward 6G, the convergence of communication and sensing is emerging as a defining feature of next-generation networks. Integrated Sensing and Communication (ISAC) enables wireless systems to not only transmit data but also sense their environment, unlocking new applications in autonomous mobility, smart cities, and industrial automation.

What is ISAC?

ISAC refers to the integration of sensing and communication functions within the same wireless infrastructure. Traditionally, radar and communication systems operated independently, requiring separate hardware and spectrum. ISAC transforms this by enabling sensing capability in the well-established mobile network, resulting in cost efficiency and enhanced capabilities.

Positioning vs. Sensing: What’s the Difference?

Positioning: This refers to estimating the location of a device or object registered with the network. In mobile networks, positioning capabilities have existed since 2G/3G era and evolved significantly in 4G LTE. Today, 5G introduces high-precision positioning using Return Trip Time (RTT), Angle of Arrival (AoA), and multi-frequency measurements, enabling centimeter-level accuracy for applications like asset tracking, emergency services, and industrial IoT.

Sensing: Unlike positioning, sensing goes beyond location—it aims to detect and interpret environmental features such as object shape, speed, and movement of objects that may be even unregistered with the network. ISAC combines these capabilities, allowing networks to become context-aware, enabling advanced applications like collision avoidance in autonomous vehicles and real-time monitoring in smart factories.

Notable Use Cases

Standardization bodies, such as ETSI and 3GPP, have outlined several practical scenarios where ISAC can deliver significant value. Here are some of the interesting examples:

1. Smart Transportation and Autonomous Vehicles
Vehicles today can rely on onboard sensors such as radar and LiDAR for navigation and safety. While effective, these sensors have limitations in range and line-of-sight. ISAC can complement these systems by using cellular infrastructure for environmental sensing.

• Drone Traffic Management: ISAC can track drones in urban airspace, supporting safe navigation and compliance with regulations.
• Collision Avoidance: Networks can detect obstacles or pedestrians beyond a vehicle’s immediate view, reducing accident risks.
• Traffic Flow Optimization: Real-time sensing data from vehicles and roadside units can help manage congestion and improve travel times.

2. Industrial Automation and Smart Factories
Future factories will require seamless interaction between humans, robots, and machines. ISAC can enable:

• Gesture Recognition: Workers can control collaborative robots using hand gestures, even in noisy or hazardous environments.
• Predictive Maintenance: Integrated sensing can detect anomalies in machinery, reducing downtime and improving efficiency.
• Safety Monitoring: Detecting human presence near restricted zones and triggering alerts or automated shutdowns.

These applications support Industry 4.0 and 5.0 goals, where connectivity and sensing work together for productivity and safety.

3. Smart Cities and Public Safety
ISAC can make urban environments more responsive and efficient:

• Sensing for UAV intrusion detection: ISAC could be used for sensing UAV intrusion in case of illegal flying in restricted areas.
• Traffic Management: Networks can sense vehicle density and pedestrian movement, adjusting traffic signals dynamically.
• Crowd Monitoring: Detecting crowd density during events for safety and emergency planning.
• Environmental Sensing: Monitoring air quality, noise levels, and structural health of critical infrastructure.

Such capabilities contribute to sustainable urban development, a key focus for future networks.

4. Healthcare and Elderly Care
Healthcare is another domain where ISAC can have a meaningful impact:

• Contactless Vital Monitoring: RF sensing can track breathing, heart rate, and posture without wearables—ideal for hospitals and elderly care homes.
• Fall Detection: Networks can detect sudden movements or inactivity and alert caregivers instantly.
• Emergency Response: Outdoor sensing can identify individuals in distress and trigger automated alerts.

These applications align with human-centric 6G services, emphasizing safety and well-being.

Operators’ Benefits

For network operators, ISAC offers multiple advantages that go beyond traditional connectivity. By integrating sensing capabilities into existing infrastructure, operators can create new revenue streams through services such as environmental monitoring, industrial automation support, and smart city applications. This approach also improves network efficiency, as sensing and communication can share spectrum and hardware resources, reducing deployment and operational costs. These benefits align with the broader industry trend toward value-added services in 5G and 6G networks, helping operators remain competitive in an evolving market.

ISAC Fundamentals

ISAC in mobile networks builds on existing infrastructure elements such as Transmission Reception Points (TRPs) and User Equipment (UE):

• TRP (Transmission Reception Point): A TRP is essentially a network node (like a base station or gNodeB) responsible for transmitting and receiving signals. In ISAC, TRPs can act as both communication anchors and sensing nodes, leveraging their wide coverage and high transmit power for environmental detection.
• UE (User Equipment): UEs include devices like smartphones, IoT sensors, and connected vehicles. With ISAC, UEs can participate in sensing either by transmitting signals for reflection analysis or by processing received signals to infer environmental information.

Monostatic vs. Bistatic vs. Multi-static

• Monostatic Sensing: Transmitter and receiver are co-located, similar to traditional radar systems.
• Bistatic Sensing: Transmitter and receiver are at different locations, enabling wider coverage and better detection in complex environments.
• Multi-static Sensing: Multiple transmitters and receivers collaborate for improved accuracy and resilience.

Figure 1: Illustration of different ISAC sensing modes

Examples of ISAC Configurations

ISAC can be implemented using TRPs and UEs in various combinations:

• TRP Monostatic: A single TRP acts as both transmitter and receiver for sensing. Example: A base station detecting objects in its coverage area using its own transmitted signal reflections.
• TRP-TRP Bistatic: One TRP transmits while another TRP receives the reflected signal. Example: Two neighboring base stations collaborating to sense vehicles at an intersection.
• TRP-UE Bistatic: A TRP transmits and a UE receives the reflected signal. Example: A smartphone using downlink signals from a base station to sense nearby obstacles.
• UE-TRP Bistatic: A UE transmits and a TRP receives the reflected signal. Example: A connected car sending uplink signals that the network uses to detect its surroundings.
• UE-UE Bistatic: One UE transmits, and another UE receives the reflected signal. Example: Two devices in proximity sensing each other’s environment for collaborative AR/VR applications.
• UE Monostatic: A single UE acts as both transmitter and receiver for sensing. Example: A smartphone using its own signals for gesture recognition or indoor mapping.

These basic modes may be extended to multi-static variants by adding additional UE(s) or TRP(s) to any of the six basic modes as sensing transmitter(s) and/or receiver(s).

Integration Levels in ISAC

The degree of integration between sensing and communication functions can vary depending on system design and deployment objectives.

Loose Integration: Sensing and communication functions are largely independent, with minimal coordination. They share spectrum or timing resources, but do not share waveform design or processing. Sensing often uses existing communication signals opportunistically without modifying the communication protocol.

Intermediate Integration: Some components are shared between sensing and communication, but not fully unified. For example, Waveform reuse – communication signals are designed with sensing in mind. Processing chains may remain separate, but there is partial coordination at the protocol level. Example: A 5G NR signal adapted for sensing tasks, where the same OFDM waveform serves both purposes, but sensing and communication have separate scheduling.

Tight Integration: Full integration of sensing and communication at hardware, waveform, and protocol levels. Example: A 6G base station simultaneously transmitting data and performing radar sensing using a single processing chain.

Challenges and Research Directions

While ISAC offers significant potential, its implementation in mobile networks faces several technical and operational challenges. Interference management is a key concern, as sensing and communication signals share spectrum and resources, requiring advanced coordination to maintain performance. Standardization gaps also exist—ETSI and 3GPP are actively defining frameworks, but many aspects, such as waveform design and protocol integration, are still evolving. Hardware complexity is another hurdle, as devices must support dual functionality without increasing cost or power consumption. Additionally, privacy and security considerations are critical, since sensing data can reveal sensitive information about users and environments.

Research is focusing on solutions such as joint waveform optimization, resource scheduling algorithms, and AI/ML-driven signal processing to improve sensing accuracy and efficiency. There is also growing interest in sensor fusion techniques and distributed sensing architectures to enable scalable deployments. These directions will shape the evolution of ISAC as a core feature of 6G networks.

Future Outlook

Integrated Sensing and Communication (ISAC) is poised to become a foundational capability in 6G networks, enabling context-aware services that enhance safety, efficiency, and user experience across industries. As standardization and industry collaboration efforts progress, ISAC will evolve from early trials to fully integrated deployments.

Through its efforts in 3GPP, Tejas Networks is actively contributing to this transformation by contributions to End-to-End system architecture and signaling design. These efforts are complemented by innovative waveform design and optimization techniques. Moreover, as India’s foremost indigenous network equipment provider, Tejas is also exploring ISAC solutions to address country-specific requirements. Examples of such requirements are- leveraging sensing technology to create unobstructed ambulance corridors, detecting obstacles on rail-tracks, and monitoring train movement in real time for accident prevention etc. By aligning with global standards and investing in research, Tejas Networks aims to play a pivotal role in shaping ISAC-enabled solutions for 6G.

References

1. ETSI
   • ETSI GR ISC 001: Integrated Sensing and Communications (ISAC); Use Cases and Deployment Scenarios
   ETSI ISAC
2. 3GPP
   • 3GPP TR 22.837: Feasibility Study on Integrated Sensing and Communication https://www.3gpp.org/ftp/Specs/archive/22_series/22.837/22837-j40.zip