Overview
ISO/IEC 24730-5:2010 specifies an air interface for real-time locating systems (RTLS) using Chirp Spread Spectrum (CSS) in the 2.4 GHz ISM band (2.4 GHz to 2.483 GHz). Part 5 of the ISO/IEC 24730 family defines bidirectional communication and two‑way ranging between RTLS readers and tags, a mandatory default mode for multi‑vendor interoperability, plus optional behaviors developers can adopt to tailor system performance.
Keywords: ISO/IEC 24730-5, RTLS, chirp spread spectrum, CSS, 2.4 GHz, air interface, two-way ranging, interoperability.
Key Topics
- Frequency and PHY requirements: Defines the 2.4 GHz spread‑spectrum air interface, transmit power spectral density (PSD) masks, and physical layer (PHY) parameters.
- Modulation modes: Specifies 2‑ary orthogonal CSS and DQPSK‑CSS modulation approaches and their PHY packet formats.
- Data framing and packet formats: Details preamble, start‑of‑frame delimiter, PHY header, MAC frame types (Data, ACK, Broadcast, RTS/CTS), and general packet structure.
- MAC sub‑layer and timing: Covers MAC timing, media access, and handshake procedures (2‑way and 3‑way), essential for reliable communication and ranging.
- Ranging and application layer: Describes two‑way ranging packet exchanges, tag application states (default, wait, range, sleep, blink), commands, and default profiles for tagging behavior.
- Compliance and coexistence: Includes compliance requirements, time base tolerances for two‑way ranging, and coexistence guidance for operation in the 2.4 GHz band.
- Informative annexes: Guidance on computing location from range values, tag roaming, and coexistence considerations.
Applications and Who Uses It
ISO/IEC 24730-5 is intended for organizations designing, deploying, or integrating RTLS solutions that require robust indoor/outdoor position measurement and device interoperability:
- RTLS system integrators and solution architects implementing location services.
- Hardware manufacturers of CSS‑based readers and tags seeking compliance and cross‑vendor interoperability.
- Wireless and RF engineers implementing PHY and MAC layers for CSS at 2.4 GHz.
- Firmware and software developers building tag application logic, APIs, and ranging algorithms.
- Facility managers and asset‑tracking teams selecting technologies for inventory, personnel safety, or process optimization.
Practical benefits include reliable two‑way ranging, resistance to interference inherent in CSS, and a standardized framework that enables multi‑vendor ecosystems.
Related Standards
- Other parts of the ISO/IEC 24730 RTLS series (defining additional air interfaces and the RTLS API).
- Regulatory and coexistence standards for operation in the 2.4 GHz ISM band (local radio regulations should be consulted when implementing).
For implementers, ISO/IEC 24730-5 provides a clear blueprint to build interoperable, CSS‑based RTLS solutions at 2.4 GHz while supporting precise ranging and flexible system behavior.
Open preview (PDF)Information technology — Real-time locating systems (RTLS) — Part 5: Chirp spread spectrum (CSS) at 2,4 GHz air interface
