January 18, 2023
Flexible Factory Partner Alliance
- Added 5G control and multi-hop functions to provide optimal wireless communication for various use cases -
In response to growing expectations for wireless commutation at manufacturing sites, FFPA has released the latest SRF wireless platform communication standard, namely technical specifications version 2.0 to the public. In the technical specifications Ver.2.0, new functions such as 5G Control for Frequency Control, 5G Control for Multi-radio Integration Control, and Multi-hop Control have been added while maintaining backward compatibility with technical specifications Ver.1.1. The technical specifications define the reference architecture, functions, message parameters among functional blocks, typical sequence diagrams and data frames for the SRF wireless platform. They can be downloaded for free from the FFPA website (https://www.ffp-a.org/document/index.html.
Flexible Factory Partner Alliance (FFPA) has established communication standards of SRF (Smart Resource Flow) wireless platform, which is a coordinated control technology that stabilizes various and mixed wireless systems in manufacturing sites. In response to growing expectations for wireless use at manufacturing sites, FFPA has released the latest SRF wireless platform communication standard, namely technical specifications Ver. 2.0.
The technical specifications Ver.2.0 define the reference architecture, functions, messages and parameters among functional blocks, typical sequence diagrams, and data frames for the SRF wireless platform, and maintain backward compatibility with the technical specifications Ver.1.1, adding coordination control of the 5th generation mobile communication system (5G) and radio systems operating in unlicensed frequency bands, and expanding the network topology to enable multi-hop communication. Fig. 1 shows the function list (excerpts of functions related to radio resource control) defined in the technical specifications Ver.2.0. 5G Control for Frequency Control, 5G Control for Multi-radio Integration Control, and Multi-hop Control have been functions newly added to the technical specifications Ver.1.1. These functions are categorized into mandatory functions, which are basic controls, and optional functions, which are selected and implemented by the vendor to characterize their own devices or systems. Messages among functional blocks are defined by REST (Representational State Transfer) API (Application Programming Interface). Also, parameters are defined using JSON (Java Script Object Notation) format. The technical specifications Ver.2.0 can be downloaded for free from the FFPA website (https://www.ffp-a.org/document/index.html).
Fig. 1. List of functions defined in the technical specifications Ver.2.0 (excerpts of functions related to radio resource.)
FFPA will exhibit at Smart Factory EXPO 2023, which will be held at Tokyo Big Sight (West 1F, West 2 Hall) from January 25th to 27th, 2023. FFPA and its member companies will present the latest technical specifications and topics related to the development of SRF wireless platform. For detail information, please contact the FFPA Secretariat (email:：email@example.com).
Challenges of wireless communication at the manufacturing sites
At manufacturing sites such as factories, it is expected to utilize more wireless technology, such as wireless communication within the factory that enables flexible changes in production lines to meet the diverse needs of consumers, and failure prediction of industrial machinery using wireless sensors . On the other hand, instability of wireless communication has become an issue due to the mixture of various wireless systems in factories and the generation of radio noise from industrial machinery . For example, in the unlicensed band used by wireless LAN, etc., multiple IoT devices are already being introduced at manufacturing sites, and if the radio waves emitted by such devices use the same frequency, they will interfere with each other and may cause communication failure, and thus, it may not be possible to maximize its potential .
FFPA tackled the issue by adopting the SRF wireless platform proposed by the National Institute of Information and Communications Technology (NICT) as the basic configuration of the system, and has developed communication standards to realize stable communication in an environment where multiple wireless systems coexist.
 White Paper 2020 on Information and Communications Japan, Ministry of Internal Affairs and Communications of Japan
 White Paper 2020 on Manufacturing, Ministry of Economy, Trade and Industry of Japan (in Japanese)
Configuration of SRF wireless platform
The SRF wireless platform consists of Field Manager, SRF Gateway, SRF Device, and SRF Sensor (Fig. 2). Field Manager is a controller that integrates and manages multiple wireless systems, coordinates wireless resources to meet application quality requirements to avoid radio wave interference, and allocates wireless resources to each wireless system according to control policies. SRF Gateway/SRF Device is a base/client unit that performs wireless communication under the control of Field Manager and notifies Field Manager of the measured wireless communication status. SRF Sensor is a wireless environmental sensor that detects and monitors wireless devices not under Field Manager control. These coordinated operations enable stable wireless communication in a wireless environment where multiple wireless systems coexist.
Fig. 2. Configuration of SRF wireless platform.
Overview of Technical Specifications Ver. 2.0 of SRF Wireless Platform
In the technical specifications Ver.2.0, in addition to wireless systems in unlicensed frequency bands that have been supported up to technical specifications Ver.1.1, 5G has been newly added as a wireless system to be appropriately controlled and it is integrally managed on the SRF wireless platform. By using the technical specifications Ver.2.0, wireless devices that support both 5G and unlicensed frequency band wireless systems will be able to achieve more stable communication and efficient frequency usage. For example, in the site where an Autonomous Mobile Robot (AMR) equipped with a combo device that supports multiple wireless systems of 5G and unlicensed frequency bands is introduced, stable communication is achievable by switching multiple wireless links and parallel transmission (Fig. 3). For example, (1) when an AMR moves while communicating on a radio system in an unlicensed frequency band, and the unlicensed frequency band is congested by other devices installed in the vicinity, the communication path is switched to 5G, and (2) when the AMR transmits and receives data related to control such as for moving and stopping, and video data from cameras mounted on AMR wirelessly, an autonomous control is conducted to transmit both data by appropriately switching between wireless systems in unlicensed frequency bands and 5G according to the congestion of the frequency band.
Furthermore, in the technical specifications Ver.2.0, a multi-hop communication function is added to relay the network with SRF Gateway, which is one of the elements consisting of the SRF wireless platform. This multi-hop communication enables wireless connections between SRF Gateways and connections between SRF Gateways via SRF Devices. This makes it possible to easily expand the coverage of stable wireless communication. In addition, by installing an SRF Gateway on a wired network, it is possible to support a mixed wired/wireless network and improve the flexibility of integrated control of multiple links, such as 5G and wired parallel transmission.
Fig. 3. 5G utilization example on SRF wireless platform
FFPA (Chairperson: Andreas Dengel, DFKI) is a non-profit organization to promote the formulation of standards for coordination control technology, ensuring stable communications in an environment where various wireless systems coexist in manufacturing facilities. Members are OMRON Corporation, the Advanced Telecommunications Research Institute International (ATR), National Institute of Information and Communications Technology (NICT), NEC Corporation, Fujitsu Limited, Sanritz Automation Co., Ltd., Murata Machinery, Ltd, Siemens K.K, and Telcom Engineering Center.
SRF Wireless Platform
System architecture to stabilize various wireless systems with connected facilities. SRF (Smart Resource Flow) is a system engineering strategy of managing resources (e. g., human, facilities, equipment, materials, energy, and communications) using multilayer system analysis to achieve optimal performance.