Satellite IoT basics | Satellite IoT network architecture
This article covers satellite IoT network architecture.It mentions satellite IoT network basics including all the elements used in the network architecture. Links to satellite and IoT tutorials are also mentioned for further study.
As we know satellite is used to provide network coverage to remote inaccessible areas on the earth. IoT stands for Internet of Things which is a network used to connect things on internet using wired/wireless connection. In order to extend IoT coverage beyond cities into remote regions; satellite and IoT networks are merged together. This integrated network will extend the IoT coverage to larger and further parts of the earth with the help of satellite.
As mentioned Satellite IoT network is combination of satellite network and IoT network. Figure-1 depicts typical satellite network architecture.
Figure-1: Satellite IoT Network Architecture
In general satellite network follows either star or mesh topology. In star configuration (as shown), VSAT to VSAT communication happens via Hub station. In mesh configuration, VSAT to VSAT communication occurs directly without the need of centralized Hub station.
NMS (Network Management Software) protocol is integrated at Hub station and remote VSATs. Hub station NMS will have monitoring and control of all the parameters of the remote VSATs while Remote NMS takes care of monitoring and control (M&C) of only remote system entities (e.g. Rf transceiver, SSPA, LNA, Modem, MUX, switches etc.) NMS software is basically will have GUI (Graphical User Interface) and protocol for user to M&C various parameters such as equipment health status, frequency, power etc. of Hub equipments as well as remote VSAT equipments.
Different types of sensors are connected with VSAT terminals for various applications such as temperature, motion, humidity, pressure etc. The sensor data are collected and transmitted to central Hub station for monitoring purpose. Moreover the network is used for voice as well as data transmission/reception. Typically IP/RS232/RS485 interface configurations are used for data interface between PC and VSAT baseband part.
As shown VSAT and Hub hardware is broadly divided into RF equipments and baseband equipments. RF equipments include RF Transceiver (Tx/Rx), Power amplifier, LNA and antenna. Baseband equipments include satellite modem, Mux/DeMux and baseband interface part (voice/data/sensor). Encryption/Decryption unit may or may not exist as per requirement of security levels. These VSAT subsystems are shown in the figure-2 below. Refer VSAT system basics>> for more information on operational working of VSAT.
Figure-2: VSAT System Block Diagram
L/C/Ku/Ka band satellites of type LEO/GEO are used in satellite IoT network. The table-1 below mentions frequencies used in these type of satellites. Note that uplink refers to transmissions from ground (i.e. VSATs) to the satellite and downlink refers to transmissions from satellite to VSATs located on the Earth.
|Satellite Bands||Frequencies used|
|L Band||1 to 2 GHz (1616 to 1626.5 MHz, both uplink and downlnk)|
|C Band||4 to 8 GHz ( 5925 to 6425 MHz in the uplink and 3700 to 4200 MHz in the downlink)|
|Ku Band||12 to 18 GHz (11.7 to 12.7 GHz in the downlink and 14 to 14.5 GHz in the uplink)|
|Ka Band||26 to 40 GHz (18.8 to 19.3 GHz in the downlink and 28.6 to 29.10 GHz in the uplink)|
Table-1: Satellite Frequency Bands
IoT part typically consists of three major entities viz. Gateway, end devices and cloud. The user end devices communicate with gateway as per IoT wireless network frequency bands. There are many IoT wireless technologies as mentioned below. The popular among them are LoRaWAN and Sigfox due to their low power and wide network area coverage. The IoT uses terrestrial communication topology for wireless air interface for communication with end devices and other wireless/wired network. The same has been shown in the figure-1 between satellite network and IoT network.
Satellite IoT network will leverage benefits of both of these wireless technologies to serve the need of individuals and corporations across the globe. Refer benefits of satellite communication and LoRaWAN and SigFox technologies.
Satellite IoT network RELATED LINKS
Following are the links useful for satellite IoT (Internet of Things) domain.
Satellite tutorial main page IoT tutorial IoT section IoT article Cellular IoT Components Sensors INDIAN companies Antenna Types Wireless technologies IoT transceiver SoC
Satellite tutorial sub topics
Following links covers all the sub topics of satellite tutorial:
What is a satellite Bands Parts Orbits Services Types capacity allocations network configurations Applications Satellite TTC Remote sensing VSAT basics