LoRaWAN Architecture | LoRaWAN network interfaces
This page describes LoRaWAN Architecture and various LoRaWAN network interfaces between its network elements. The LoRaWAN architectures for end device at home and while roaming have been described.
LoRaWAN is one of the popular LPWAN technology used for long range wireless communication. The LoRaWAN network consists of End Devices and LoRaWAN gateway and network servers. LoRaWAN offers 5 km range in urban areas and 15 km in suburban areas.
LoRaWAN devices consume very low power and supports different frequency bands viz. 863 to 870 MHz, 902 to 928 MHz and 779 to 787 MHz in different regions of the world.
The LoRaWAN devices are categorized into three main classes viz. class-A, class-B and class-C based on their application need. The figure-1 depicts network topology of LoRaWAN system. As shown its elements are connected using "star of stars" topology.
LoRaWAN network architecture (End device at home)
The figure-2 depicts LoRaWAN network architecture with its elements. Let us understand
functions of each.
End Device : This LoraWAN device functions as sensor or actuator. It connects wirelessly with LoRaWAN network through LoRaWAN gateway as shown. All the payloads of an application layer are routed to its connected application server in the cloud.
LoRaWAN gateway Device : It forwards received radio packets to network server through backbone. It receives radio packets from air and forward them to network server without any processing. Similarly it does not alter payloads coming from network server to be uploaded over the air. It does necessary RF conversion.
Network Server (NS) : There are many functions performed by NS as follows. It does end device address checking. The other functions are frame authentication, acknowledgements, data rate adaptation etc. It interfaces with application server and Join server. NS has three roles (Home, Serving, Forwarding) based on roaming situation and type of roaming.
Join Server (JS) : It manages the OTA activation process of end devices. The several JSs are connected to single NS. Moreover a JS may connect to several NSs.
Application Server (AS) : The Application Server handles all the application layer payloads of the associated LoRaWAN End-Devices. It provides the application level service to the end-user.
LoRaWAN network interfaces
Following table mentions LoRaWAN network interfaces used between its network elements.
|LoRaWAN Interface types||Description|
|hNS-JS||• Used for activation procedure between join server and network server.|
|vNS-JS||• Used for roaming activation procedure to retrieve NetID of hNS associated with End device.|
|ED-NS||• LoRaWAN MAC layer signaling
• payload delivery between End device and Network server.
|AS-hNS||• Delivery of application payload• to associate meta-data between AS (Application Server) and NS (Network Server).|
|hNS-sNS||• Roaming signaling and Payload delivery between home network server (hNS) and Serving NS (sNS).|
|sNS-fNS||• Roaming signaling and Payload delivery between serving network server (sNS) and forwarding NS (fNS).|
|AS-JS||• To deliver application session key from Join server (JS) to Application server (AS).|
Reference: LoRaWAN Backend Interfaces document V1.0, Visit www.lora-alliance.org to download it.