SigFox Uplink and Downlink Data Call Flow Procedure
Introduction : SigFox, a leading LPWAN technology, enables efficient IoT communication using minimal power. Understanding the uplink and downlink data call flow procedure is crucial for optimizing SigFox device communication. This article outlines the step-by-step process of message flow between SigFox devices, base stations, and the backend, detailing the key elements involved in data transmission. The uplink is from LEP to LAP and downlink is from LAP to LEP directions.
About Sigfox: It is a low power and low data rate wide area networking wireless technology. Due to its lower throughput, the system is also known as LTN (Low Throughput Network). It operates in ISM bands 868 and 915 MHz. There are four basic entities in the sigfox wireless system. They are LEP (LTN End Point or objects), LAP (LTN Access Point or Base Stations or Gateways) , WAN (e.g. Cloud) and servers.
The flow of information through the sigfox system is known as data flow. In order to send or receive data, data call need to be established. The transmission of data from LEP to LAP direction is known as uplink and transmission of data from LAP to LEP direction is known as downlink. Based on this, there is uplink data call and downlink data call.
Sigfox Uplink Data Flow
Following are the steps associated during sigfox uplink data flow:
➨Whenever there is information to be sent, LEP (LTN End Point or Sigfox object) just occupies the RF channel and
transmits over the air.
➨The information is received by one or multiple LAPs (or base stations).
➨Each LAP down convert, demodulate and decode the received RF packet.
➨Each LAP forwards the decoded message to LTN server using secured IP link.
➨LTN Server performs authentication and authorization of the message and pushes the
message to the application provider server. Standard APIs are used in order to push or pull
message to to/from application server.
➨This completes the Sigfox uplink data call.
Sigfox Downlink Data Flow
Following are the steps associated during sigfox downlink data flow.
➨In order to receive data in the downlink, LEP opens fixed window after uplink transmission.
➨This window is used by LAPs to send the information to respective LEP intending to receive information.
➨Application server transmits the message to LTN server.
➨LTN server forwards this message to the appropriate LAP.
➨The LAP transmits the message to the LEP in the time slot opened by it (i.e. LEP).
➨This completes the sigfox downlink data call.
References: ETSI GS LTN 002 (Low Throughput Networks) document.
Conclusion
SigFox’s simplified uplink and downlink data call flow is designed for low-power, cost-effective IoT communication. By understanding these procedures, developers can enhance device performance and tailor applications to suit specific IoT needs.