Overview
This note proposes an extension of ISO/IEC 18000-63 (2021) specification (hereinafter, Gen2)[1] or a new stream of protocol to enable concurrent sensor data streaming from multiple radio frequency (RF) tags with the multiple subcarrier multiple access (MSMA) technology [2] using backscatter technology. The basic composition of the MSMA system comprises a reader/writer (hereinafter, reader) and a group of multiple backscatter tags (Figure 1).
As shown in Figure 1, an MSMA tag comprises an RF integrated circuit (RFIC), which handles the communication with the reader, and a sensor connected to RFIC through, for example, the serial peripheral interface (SPI) in our implementation. The power to the sensor can be provided by RFIC, which is the SPI master, and the sensor is an SPI slave.
The concurrency in MSMA in its sensor streaming stage is realized by simultaneously using multiple subcarriers. The Miller encoded subcarrier is extensively used in commercial RFID systems with Gen2 protocol. However, only one tag responds to its reader at a time. In MSMA, each tag in the view field of the reader is assigned a narrowband subcarrier channel by the reader, then the sensor data can be concurrently streamed using the dedicated subcarriers. An overview of the communication protocol and MSMA tags is explained in the following document.
- “ISO/IEC 18000-63, Information Technology – Radio frequency identification for item management- , Part 63 parameters for air interface communications at 860 MHz to 960 MHz type C,” 2015.
- J. Mitsugi, Y. Kawakita, K. Egawa and H. Ichikawa, “Perfectly Synchronized Streaming From Multiple Digitally Modulated Backscatter Sensor Tags,” IEEE Journal of Radio Frequency Identification, vol. 3, no. 3, pp. 149-156, Sept. 2019, doi: 10.1109/JRFID.2019.2914246.
Proposal document (latest version)
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