Internet of Things (IoT) is an interconnection of objects (or things), sensors, embedded processor/controller, software, and wireless connectivity protocols. The basic function of any IoT device is to gather & share information with user applications or other IoT devices over internet and perform certain control functions based on analytics and users' input.

IoT today finds applications in different industry sectors both product and services. Few examples are automotive, facility management, consumer electronics, connected cities, utilities, smart buildings, e-health, supply chains etc. Other than these industrial applications, IoT find use in critical applications like early warning during natural disasters, weather monitoring etc.

As we know wireless communication or connectivity forms the basis of any IoT system. There are a lot of connectivity options available to build an IoT system and some of them are Bluetooth, Zigbee, Cellular (3G/4G), NFC etc. The choice of any one connectivity option is totally dependent upon the IoT system under consideration and is influenced by parameters like complexity of the system (number of nodes etc), range, power consumption, security etc. One of the new connectivity protocols that is gaining momentum these days for IoT is LoRa - Long Range, Low Power technology offering secure data transmission.

LoRa Technology

It offers long range when compared to existing standard and is very easy to plug into existing internet infrastructure. MAC layer has been added to regulate and expand the LoRa physical communication layer on top of internet networks. This MAC layer is called the LoRaWAN (LoRa for Wide Area Networks) specification. It is open sourced and maintained by the LoRa association. The LoRaWAN also consist of numerous important wireless network elements like adaptive data rate optimization, E2E encryption & security, quality of service, and other latest communication applications. LoRa works great for distantly installed applications that necessitate long-range and deep in-building communication for a large number of devices that require low power and low data rate. LoRaWAN networks are normally structured as "star-of-stars" topology where base stations transmit messages between end-devices and a central core network server. All base stations are linked to the core network server through standard IP links whereas end-devices use single-hop LoRa communication to one or many base stations as shown in figure below.

Applications of LoRa

LoRa provides data rate ranging from 300 bps to 5 kbps for a 125-kHz bandwidth improving the battery life and capacity of the system. LoRa network organization use an Adaptive Data Rate (ADR) scheme to accomplish the specific data rates and RF output of every linked device. It makes use of license-free band generally ISM (Industrial, Scientific, Medical) bands to exchange information over the wireless media.

This technology is designed to answer use cases as shown in figure on the right where a sensor transmits small amount of data few times a day for applications like smart metering, trackers, wearables etc. It can also be used to control other wireless device capabilities; such as, to remotely give instruction to camera to start a data transmission and stay in low power mode otherwise.

Security in LoRa

A LoRaWAN network solution derives with a security framework and baseline authentication built on AES-128 encryption system and additional well-known security standards. As related to some other methods which depend on single key for encryption and authentication, the LoRaWAN technology isolates encryption and authentication so that it is able to verify packets and offer integrity protection.

Integrity control and authentication usage of network session key (NwkSKey); user payload encryption usage of application session key (AppSKey) as shown in figure below. Both AppSKey and NwkSKey are AES-128 root keys explicit to the end-device that are allotted by the device manufacturers. The LoRaWAN central network server solution provides two authentication and activation methods like Over-The-Air Activation (OTAA) and Activation by Personalization (ABP).

By - Dr. Bhisham Sharma - CURIN Chitkara University

References:-

1. Barrachina-Muñoz, Sergio, et al. "Multi-hop Communication in the Uplink for LPWANs.", Computer Networks (2017).
2. Sinha, Rashmi Sharan, Yiqiao Wei, and Seung-Hoon Hwang. "A survey on LPWA technology: LoRa and NB-IoT.", ICT Express (2017).
3. Yao, Yuan, et al. "LORA: Loss Differentiation Rate Adaptation Scheme for Vehicle-to-Vehicle Safety Communications.", IEEE Transactions on Vehicular Technology 66.3 (2017): 2499-2512.