Wireless IoT

In this article, we’ll look into different IoT wireless technologies. We’ll analyze 3G, which use cellular line to send data, SigFox, with its growing coverage, and Wireless M-Bus if you need your own network infrastructure or hidden area with no other coverage (tunnels). 

2G/3G

Standard: GSM/GPRS/EDGE(2G), UMTS/HSPA(3G), LTE(4G)
Frequencies: 900/1800/1900/2100MHz
Range: 35Km max for GMS, 200Km max for HSPA (Depending on ISP)
Data Rates (typical download): 35-170kps(GPRS), 120-384kbps (EDGE),384kbps-2Mbps(UMTS), 600kbps-10Mbps(HSPA), 3-10Mbps (LTE)
Power Consumption: 580mA during transmission (depends signal quality)

GSM/2G/3G can be the right choice for IoT application that requires long distance transmission. Cellular line has a great bandwidth, but subscription cost and power requirements are high too. OMNIAlog and miniOMNIAlog trasmit a low amount of data (depending on sensor number and sampling rate, but still sensor reading) so the required bandwidth is usually low.

SigFox

Frequencies: 868MHzISM Frequency
Range: Long Range (30-50Km (rural environments), 3-10Km (urban/noisy environments))
Data Rates: 10-1000bps
Ultra Narrow Band: few seconds transmission for a maximum of 140 times per day (12bytes payload)
Devices’ frequency stability
Low Band Pass: 100bit/sec (perfect for IoT short messages)
Sigfox receiver: UNB Technology with Cognitive SDR – 140dBm (5-20Km range) and handles 3000000 devices.
Power Consumption: 61mA during transmission

SigFox is going to fill the spot between wi-fi and cellular line. Some application require indeed only few data transfers (like miniOMNIAlog datalogger) and requres to run on battery for long periods of time. The ISM band is license-free. The idea for Sigfox is that many m2m application runs on small battery and only need few data to be transfered. SigFox is expanding fast, with 24 countries reached (France, Spain, Portugal, Netherlands, Luxembourg, Ireland, U.S., U.K., Belgium, Denmark, Italy, Czech Republic, Mauritius Island, Germany, Australia, New Zealand, Sultanate of Oman, Brazil, Finland, Malta, Mexico, Singapore, Taiwan, Colombia).

M-Bus – Wireless

Frequencies: 169/868/915MHz
One/Two Way Narrowband VHF
NRZ-encoded
Optimized for narrowband and long range (5Km in line of sight)
Star architecture
Power Consumption: 485mA during transmission

The 169MHz WM-Bus is the wireless variant of M-Bus standard. Born for remote reading of gas and elecrticity meters, soon become an european standard (EN13757). It was developed to provide a system for remote reading of utility meters, like consumption of electricity in the home. M-Bus (and its wireless variant) grant power requirements of battery-prowered devices.

M-Bus is also commonly used in alarm systems, smart illumination systems and other application which require low power consumption and sturdy communication protocol.