Samsung Research Details Ambient IoT Design for Battery-Free 6G Connectivity

Samsung Research proposes Ambient IoT as a battery-free device layer for mobile networks, targeting objects that cannot afford conventional cellular modems or batteries. Unlike passive RFID which requires handheld scanners, Ambient IoT allows base stations or network-controlled smartphones to act as readers, enabling continuous, wide-area inventory management.

Device Constraints and Requirements

These devices harvest energy from radio waves, light, heat, or vibration, consuming roughly 1 microwatt to a few hundred microwatts. They exchange only a few hundred bits at a time and may be temporarily unavailable while harvesting energy. The design targets specific performance metrics:

• Throughput: 0.1–5 kbps
• Latency: 1–10 seconds
• Density: Up to 150 devices per 100 m² indoors
• Coverage: Tens of meters indoors to hundreds of meters outdoors

Technical Implementation

Ambient IoT operates in NR FDD bands such as n28 (700 MHz), n5 (850 MHz), and n8 (900 MHz). It utilizes a simplified radio interface relying only on PHY and MAC layers, avoiding the full protocol stack of conventional cellular devices. Transmission techniques include on-off keying (OOK) for reader-to-device signals and OOK or binary phase-shift keying (BPSK) for device-to-reader signals. This approach eliminates the need for complex OFDM demodulation, reducing power consumption and cost.

Design Principles for Sustainability

The article argues that Ambient IoT will succeed only if the common foundation remains simple. Key design principles include:

• Energy Availability as Normal Behavior: Procedures must tolerate interrupted exchanges and avoid unnecessary retries, treating device unavailability as a standard operating condition.
• Flexible Reader Function: The network must coordinate various reader types (base stations, smartphones, fixed nodes) without creating separate systems for each environment.
• Standardized Interoperability: Security, identity, and basic capability signaling require common rules, while deployment-specific choices like reader placement remain flexible.

The ultimate goal is not to maximize tag capability, but to keep very inexpensive items reliably reachable for long periods using licensed spectrum and core-network integration.