Over the Air Programming (OTAP)

The concept of Wireless Programming, commonly know as Programming Over the Air (OTAP) has been used in the past years overall for the reprogrammation of mobile devices such as cell phones. However, with the new concepts of Wireless Sensor Networks, M2M and the Internet of Things where the networks consist of hundreds or thousands of nodes OTA is taken to a new direction, and for the first time it is applied using both: mobile phone technologies such as 3G and GPRS and unlicensed protocols such as WiFi, 802.15.4 and ZigBee.

There are two different OTAP methodologies:

» OTAP with 802.15.4/ZigBee

OTAP 802.15.4


  • Enables the upgrade and change of firmware versions without physical access
  • Let discover nodes in the area just sending a broadcast discovery query
  • Enables to upgrade an entire network in few minutes
  • No interferences are caused: OTAP is performed using a change of channel between the programmer and the desired node


  • Direct access: when the nodes are accessed in just one hop (no forwarding of the packets is needed)
  • Multihop: when the nodes are accessed in two or more hops. In this mode some nodes have to forward the packets sent by the Gateway in order to reach the destination


  • Locate the node to upgrade
  • Check current software version
  • Send the new program
  • Reboot and start with the new program
  • Restore the previous program if the process fails

Encryption and Authentication

All the data which is sent in the OTAP process can be secured by activating the encryption algorithm AES 128b which works in the link layer. As well as this, a second pass key is needed to be known by the OTA programmer (the Gateway) in order to be authenticated and validated by each node before starting with the OTAP action requested.


  • Unicast: Reprogram an specific node
  • Multicast: Reprogram several nodes at the same time sending the program just once
  • Broadcast: Reprogram the entire network sending the program just once

Storage System

Once we have sent the program to Waspmote it will store it in the internal memory, a 2GB SD card. If we have into account that the maximum size for a program is 128KB, this means we can store thousands different firmware versions inside each node.


The OTA-Shell application can be used in Windows, Linux and MacOS. It allows to control in a quick and powerful way all the options available in OTA. If you are using Meshlium as the Gateway of the network, the OTA-Shell environment comes already preinstalled and ready to use. This is the recommended way when deploying a real scenario.


In order to know more about OTAP including how to download and use the OTA Shell application please go to the Development section:

» OTAP with 3G/GPRS/WiFi via FTP


  • Enables the upgrade or change of firmware versions without physical access.
  • Upgrades the new firmware by querying a FTP server which helps to keep battery life.
  • Enables to upgrade an entire network in few minutes


  • Waspmote queries the FTP server for a new program version
  • Check if program name, path and version are correct
  • Download the new program
  • Reboot and start with the new program



  • Protocols which support FTP transmissions are directly connected to the Network Access Point

OTAP Wifi 3g

Protocols supported

  • 3G - Tri-Band (2100/1900/900 MHz)
  • GPRS - Quad-Band (850/900/1800/1900 MHz)
  • WiFi - 2.4GHz (Worldwide)

Storage System

Once the program is downloaded to Waspmote it is stored it in the 2GB SD card.

Meshlium OTA-FTP plug-in

Meshlium (the Gateway of the Sensor Network) provides a FTP server and Manager System plug-in which permits to configure the server automatically by attaching the program binary file to be used.

OTA Meshlium Plugin


In order to know more about OTAP including how manage Meshlium to act as FTP Server for the modes of the Network, download the OTAP guide from:


The concept of OTAP may have some other names such as:

  • Over the air -> OTA
  • Over the air Programming -> OTAP
  • Firmware over the air -> FOTA
  • Programming Over the air-> POTA
  • Over the air service provisioning -> OTASP
  • Over the air provisioning -> OTAP
  • Over the air parameter administration -> OTAPA
  • Over the air upgrade -> OTAU
  • Over the air update -> OTAUR
  • Over the air Download -> OAD
  • Over the air flashing -> OTAF
  • Over the air parameter administration -> OTAPA
  • Multihop Over the air programming (MOTAP)

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