Low cost IoT technologies for Smart Cities
06 May 2020
According to the study made by experts from Norwegian University of Science and Technology, the IQRF wireless technology has many pros for using in the Smart City area.
BLUETOOTH LOW ENERGY
Bluetooth Low Energy (BLE) is a short-range wireless technology
operating at 2.4 GHz frequency band which can be a problem in cities flooded with 2.4 GHz Wi-Fi networks. It enables low-power communication between the devices due to its shorter wavelength radio signals. Originally, Bluetooth was designed for Star network which limits the coverage range. Thus, it is appropriate to use for point-to-point, single-link applications. Recently, the latest versions of BLE (BLE 5.0-5.1) have adapted the Mesh network topology.
ZigBee is another short-range wireless communication technology based on the 802.15.4 standard that operates at 2.4 GHz. To extend its coverage, it is generally deployed in Mesh network. However, the Mesh configuration adversely affects its power-efficiency. Still, when comparing with BLE, it can achieve higher data rates. It is generally used in various smart city applications such as monitoring of wireless networks, logistics, traffic management, and smart lighting.
SigFox provides a LPWAN technology that uses the ultra-narrow band (UNB) spectrum channel for data transmission. In this technology, IoT devices transmit the data to the SigFox gateways. Its network has a Star topology where these gateways are able to communicate with SigFox cloud. Since data transmission is low, this technology enables IoT devices to reduce energy consumption. Besides, the coverage can achieve a more extended range. In rural environments, its coverage is 30 to 50 km whereas in urban environments the coverage is extended from 3 to 10 km. With recent developments, it supports both unidirectional and bidirectional communication.
LoRa is a well-known LPWAN radio technology in today's competitive IoT market. It provides several advantages like reducing device cost, enhancing network capacity, and increasing devices' battery life. Its physical layer modulates the signal in a sub-GHz band using chirp-spread-spectrum
(CSS) modulation. This yields to extend the coverage range, in order of 5 km and 15 km in urban and rural environments, and to endure the environmental obstacles/interferences. LoRaWAN uses Star topology where the central
node is considered as a gateway. This increases the devices' battery lifetime especially when long-range connectivity is desired.
AN ALTERNATIVE LOW-COST IoT WIRELESS TECHNOLOGY: IQRF
In addition to technologies mentioned in the previous section, IQRF technology, which has recently developed for wireless connectivity, offers low-cost wireless solutions for smart cities. In this section, an overview of IQRF technology and its actual and potential usage in smart city applications is presented. Its potential benefits over relevant technologies in low-cost communication aspects are also discussed by making theoretical comparisons.
IQRF is a technology/platform which includes transceivers, gateways, development tools, protocols, and supporting services. It provides reliable, low-power, low-speed, and low-data wireless connectivity in sub-GHz ISM bands (433MHz, 868MHz, and 916MHz). The coverage range extends from tens to hundreds of meters. However, the range could be extended up to several kilometers in certain conditions. Thus, it can be easily used for different application domains where a wireless transfer from any electronic equipment to a wireless network is required. It is based on packet-oriented communication. Using IQRF technology is extremely simple, and it is ideal to implement IoT.
Comparison between IQRF and short/medium range IoT wireless technologies
|Operating Frequency||2.4 GHz||2.4 GHz||433, 868, 916 MHz|
|Data Rate (kb/s)||2000||250||20|
|Max. Payload (byte)||251||128||64|
|Max. Range (free-space)||400 m||300 m||1 km|
|Topology||Mesh||Star, Mesh, Tree||Mesh|
|Power Consumption (max.)||15 mA||30 mA||15 μA|
|Max. Transmission Power (dBm)||20||20||11|
|Nodes per Gateway||65x103||65x103||65x103 (OS), 240 DPA|
|Battery lifetime (years)||1 - 2||2||5 - 10|
Comparison between IQRF and long-range IoT wireless technologies
|Operating Frequency||868 MHz, 902 MHz||433, 868, 780, 915 MHz||433, 868, 916 MHz|
|Data Rate (kb/s)||0.1||0.3 - 37.5||20|
|Max. Payload (byte)||12||243||64|
|Max. Range (free-space)||50 km||15 km||1 km|
|Latency (ms)||> 1000||> 1000||400|
|Power Consumption (max.)||1 mA||1 mA||15 μA|
|Max. Transmission Power (dBm)||27||14||11|
|Nodes per Gateway||10||10||65x10 (OS), 240 (DPA)|
|Battery Lifetime (years)||5 - 10||5 - 10||5 - 10|
Source: M. Bouzidi, Y. Dalveren, F. A. Cheikh and M. Derawi, "Use of the IQRF Technology in Internet-of-Things-Based Smart Cities," in IEEE Access, vol. 8, pp. 56615-56629, 2020, doi: 10.1109/ACCESS.2020.2982558.