Method and apparatus for updating firmware

An apparatus for updating firmware of a router and a terminal node in a multi hop-based Internet of things (IoT) wireless network system including an access point, a plurality of routers, and a plurality of terminal nodes, the apparatus being configured to operate as a node in the wireless network system and comprising:

• a processor;
• and a memory having instructions stored thereon, which, when executed by the processor, cause the processor to:
• operate as an over-the-air (OTA) master when the apparatus acts as a parent node and operate as an OTA slave when the apparatus acts as a child node;
• when operating as the OTA master,
• transmit an OTA ready beacon frame to OTA slaves wirelessly connected to the apparatus and receive, from the OTA slaves, OTA ready response frames indicating a ready state;
• perform a downloading operation comprising transmitting firmware data to an OTA slave that is ready to download the firmware in units of blocks;
• perform a resend operation comprising receiving, from the OTA slave, an OTA resend request identifying one or more firmware data blocks that have not been successfully received by the OTA slave, and retransmitting the identified firmware data blocks to the OTA slave in response to the OTA resend request, wherein the resend operation is performed during or after the downloading operation;
• and
• transmit an OTA complete beacon frame when no further OTA resend request is received,
• wherein, before a ready operation corresponding to the ready state,
• the access point transmits a beacon frame indicating a normal mode to the router, and the router relays the beacon frame and sends the beacon frame to other routers and terminal nodes that constitute the wireless network, and
• sensor data collected by terminal nodes is transmitted to the access point via the routers during the normal mode.