With the rapid growth of the internet of Things (IoT) paradigm, another important technology appears on the research field that helps in earning a high performance wireless communication between devices, it is called low power wide area network (LPWAN). In the LPWAN technology, there are two categories: Long Rang (LoRa) and narrowband (NB-IoT). LoRa is not only a long-range network; it also enables the transfer of information with a low transfer rate and low power consumption. Additionally, LoRa wireless area network (LoRaWAN) is a promising technology developed to overcome the IoT applications challenges.

1. What is Lora and LoraWan?

Before getting into the Lora concept, we should learn about LPWAN.

One technology cannot serve all of the projected applications and volumes for IoT. WiFi and BTLE are widely adopted standards and serve the applications related to communicating personal devices quite well. Cellular technology is a great fit for applications that need high data throughput and have a power source. LPWAN offers multi-year battery lifetime and is designed for sensors and applications that need to send small amounts of data over long distances a few times per hour from varying environments.

Source: i-scoop.eu

The most critical factors in a LPWAN are:

• Network architecture
• Communication range
• Battery lifetime or low power
• Robustness to interference
• Network capacity (maximum number of nodes in a network)
• Network security
• One-way, two-way communication
• Variety of applications served

Source: everythingrf.com

LoRa and LoraWAN sensor belong to the category of non-cellular LPWAN wireless communication network protocols and players, operating in the license-free spectrum. Other technologies that operate in the license-free frequency bands include Sigfox, Ingenu and several more.

LoRa is the physical layer or the wireless modulation utilized to create the long range communication link. Many legacy wireless systems use frequency shifting keying (FSK) modulation as the physical layer because it is a very efficient modulation for achieving low power. LoRa is based on chirp spread spectrum modulation, which maintains the same low power characteristics as FSK modulation but significantly increases the communication range. Chirp spread spectrum has been used in military and space communication for decades due to the long communication distances that can be achieved and robustness to interference, but LoRa is the first low cost implementation for commercial usage.

Long Range (LoRa) The advantage of LoRa is in the technology’s long range capability. A single gateway or base station can cover entire cities or hundreds of square kilometers. Range highly depends on the environment or obstructions in a given location, but LoRa and LoRaWAN have a link budget greater than any other standardized communication technology. The link budget, typically given in decibels (dB), is the primary factor in determining the range in a given environment. Below are the coverage maps from the Proximus network deployed in Belgium. With a minimal amount of infrastructure, entire countries can easily be covered.

LoRaWAN defines the communication protocol and system architecture for the network while the LoRa physical layer enables the long-range communication link. The protocol and network architecture have the most influence in determining the battery lifetime of a node, the network capacity, the quality of service, the security, and the variety of applications served by the network.

Source: thethingsnetwork.org

2. A Brief History of LoRa and LoraWan

The story of LoRa began in 2009, when two friends in France aimed at developing a long range, low power modulation technology. Despite encountering resistance, as with most disruptive technologies, Nicolas Sornin and Olivier Seller continued dedicating their time to turn the idea into a reality. In 2010, Nicolas and Olivier met their third partner, François Sforza, and together they started the company Cycleo. Initially, the three founders were targeting the metering industry and aimed at adding wireless communication capabilities for gas, water and electricity meters.

For this purpose, they used Chirp Spread Spectrum (CSS) modulation technology, a technology widely in use for sonar in the maritime industry and radar in aviation. Also, in the animal kingdom we see this physical phenomena used by dolphins and bats to detect fish or insects. In fact, Cycleo did not invent CSS technology, rather, they initiated the use of the technology for sending data.

Convinced about the long range and low power capabilities of the invention, Semtech acquired Cycleo in May 2012. Semtech collaborated with Nicolas, Olivier and François to further improve the technology and finalize the chips required for the end devices (SX1272 and SX1276), as well as for the gateways (SX1301). At the same time, the creation of the proprietary MAC protocol called “LoRaMAC”, among other things, specified the message formats and security layers for a true networking protocol. In February 2015, the LoRa Alliance® was founded and the networking protocol was renamed “LoRaWAN.” The LoRa Alliance’s goals were, and still are, to “support and promote the global adoption of the LoRaWAN standard by ensuring interoperability of all LoRaWAN products and technologies.”

3. LoraWan technology

Network Architecture

Many existing deployed networks utilize a mesh network architecture. In a mesh network, the individual end-nodes forward the information of other nodes to increase the communication range and cell size of the network. While this increases the range, it also adds complexity, reduces network capacity, and reduces battery lifetime as nodes receive and forward information from other nodes that is likely irrelevant for them. Long range star architecture makes the most sense for preserving battery lifetime when long-range connectivity can be achieved.

Source: rs-online.com

In a LoRaWAN network nodes are not associated with a specific gateway. Instead, data transmitted by a node is typically received by multiple gateways. Each gateway will forward the received packet from the end-node to the cloud-based network server via some backhaul (either cellular, Ethernet, satellite, or Wi-Fi). The intelligence and complexity is pushed to the network server, which manages the network and will filter redundant received packets, perform security checks, schedule acknowledgments through the optimal gateway, and perform adaptive data rate, etc. If a node is mobile or moving there is no handover needed from gateway to gateway, which is a critical feature to enable asset tracking applications–a major target application vertical for IoT.

Battery Lifetime

The nodes in a LoRaWAN network are asynchronous and communicate when they have data ready to send whether event-driven or scheduled. This type of protocol is typically referred to as the Aloha method. In a mesh network or with a synchronous network, such as cellular, the nodes frequently have to ‘wake up’ to synchronize with the network and check for messages. This synchronization consumes significant energy and is the number one driver of battery lifetime reduction. In a recent study and comparison done by GSMA of the various technologies addressing the LPWAN space, LoRaWAN showed a 3 to 5 times advantage compared to all other technology options.

Network Capacity

In order to make a long range star network viable, the gateway must have a very high capacity or capability to receive messages from a very high volume of nodes. High network capacity in a LoRaWAN network is achieved by utilizing adaptive data rate and by using a multichannel multi-modem transceiver in the gateway so that simultaneous messages on multiple channels can be received. The critical factors affecting capacity are the number of concurrent channels, data rate (time on air), the payload length, and how often nodes transmit. Since LoRa is a spread spectrum based modulation, the signals are practically orthogonal to each other when different spreading factors are utilized. As the spreading factor changes, the effective data rate also changes. The gateway takes advantage of this property by being able to receive multiple different data rates on the same channel at the same time. If a node has a good link and is close to a gateway, there is no reason for it to always use the lowest data rate and fill up the available spectrum longer than it needs to. By shifting the data rate higher, the time on air is shortened opening up more potential space for other nodes to transmit. Adaptive data rate also optimizes the battery lifetime of a node. In order to make adaptive data rate work, symmetrical uplink and downlink is required with sufficient downlink capacity. These features enable a LoRaWAN network to have a very high capacity and make the network scalable. A network can be deployed with a minimal amount of infrastructure, and as capacity is needed, more gateways can be added, shifting up the data rates, reducing the amount of overhearing to other gateways, and scaling the capacity by 6-8x. Other LPWAN alternatives do not have the scalability of LoRaWAN due to technology trade-offs, which limit downlink capacity or make the downlink range asymmetrical to the uplink range.

Device Classes – Not All Nodes Are Created Equal

End-devices serve different applications and have different requirements. In order to optimize a variety of end application profiles, LoRaWAN™ utilizes different device classes. The device classes trade off network downlink communication latency versus battery lifetime. In a control or actuator-type application, the downlink communication latency is an important factor.

Source: lora-alliance.org

Bi-directional end-devices (Class A): End-devices of Class A allow for bi-directional communications whereby each end-device’s uplink transmission is followed by two short downlink receive windows. The transmission slot scheduled by the end-device is based on its own communication needs with a small variation based on a random time basis (ALOHA-type of protocol). This Class A operation is the lowest power end-device system for applications that only require downlink communication from the server shortly after the end-device has sent an uplink transmission.

• Downlink communications from the server at any other time will have to wait until the next scheduled uplink. Bi-directional end-devices with scheduled receive slots (Class B): In addition to the Class A random receive windows, Class B devices open extra receive windows at scheduled times. In order for the end-device to open its receive window at the scheduled time, it receives a time-synchronized beacon from the gateway. This allows the server to know when the end-device is listening.
• Bi-directional end-devices with maximal receive slots (Class C): End-devices of Class C have almost continuously open receive windows, only closed when transmitting.

Security

It is extremely important for any LPWAN to incorporate security. LoRaWAN™ utilizes two layers of security: one for the network and one for the application. The network security ensures authenticity of the node in the network while the application layer of security ensures the network operator does not have access to the end user’s application data. AES encryption is used with the key exchange utilizing an IEEE EUI64 identifier. There are trade-offs in every technology choice but the LoRaWAN™ features in network architecture, device classes, security, scalability for capacity, and optimization for mobility address the widest variety of potential IoT applications.

Advantages and Disadvantages of LoRaWAN

Advantages of LoRaWAN

• Low Powered sensors, and wide coverage area measured in kilometers
• Operates on free(unlicensed) frequencies, no upfront licensing cost to use the technology
• Low power means long battery life for devices. Sensor batteries can last for 2–5 years (Class A and Class B)
• Single LoRa Gateway device is designed to take care of thousands of end devices or nodes
• It is easy to deploy due to its simple architecture
• It is widely used for M2M/IoT applications
• Better payload size (100 bytes), compared to SigFox which is 12 bytes
• Open: an open alliance and an open standard. Open technology compared to competitor SigFox
• No restriction in maximum number of daily messages (compared to SigFox limitation of 140/day)
• LoRaWAN has the benefit of being an alliance with an Open approach instead of a proprietary one (SigFox).
• Long range enables solutions such as smart city applications.
• Low bandwidth makes it ideal for practical IoT deployments with less data and/or with data transmissions which aren’t constant.
• Low(er) connectivity costs.
• Wireless, easy to set up and fast deployment.
• Security: a layer of security for the network and one for the application with AES encryption.
• Fully bi-directional communication.
• Backed by the likes of CISCO, IBM and 500 other member companies of the LoRa Alliance.

Disadvantages of LoRaWAN

• Not for large data payloads, payload limited to 100 bytes.
• Not for continuous monitoring (except Class C devices).
• Not ideal candidate for real time applications requiring lower latency and bounded jitter requirements.
• Densification of LoRaWAN networks: The proliferation of LPWAN technologies, and particularly LoRaWAN, poses coexistence challenges as the deployment of gateways populate urban areas.
• Disadvantage of open frequency is that you may get interference on that frequency and the data rate may be low. (For GSM or licensed frequency you can transmit on that frequency without any interference. GSM operators that use certain frequencies pay a large licensing fee to the government for the use of those frequencies. LoRa operates on frequencies that are open and do not need a state license. Keep in mind though that the open frequencies are different from country to country).

4. Comparison of LoRa and LoRaWAN with competitors

4.1 LoraWan vs Sigfox

Both LoRaWAN and Sigfox provide wireless data connectivity for the long range, low power segment. However, LoRaWAN and Sigfox are very different technologies and business models. The table below highlights some of these.

Drawbacks of SigFox,

• It is not deployed everywhere, so it won’t work for a large number of use cases currently.
• Communication is better headed up from the endpoint to the base station. It has bidirectional functionality, but its capacity from the base station back to the endpoint is constrained, and you’ll have less link budget going down than going up.
• Mobility is difficult with Sigfox devices.
• Sigfox is uplink only. Though limited downlink is possible, it has a different link budget and is very restricted.

4.2 LoraWan vs NB iot

LoRa and Sigfox fall under non-cellular IoT technologies. NB-IoT falls under the cellular IoT category. NB-IoT works on a cellular, licensed spectrum, the devices have to be synced with the network at regular (and relatively frequent) intervals. No such network synchronization is required in the ALOHA-based LoRa architecture.

The LoRa IoT technology works on license free radio frequency spectrum (Sigfox does the same). Accordingly, applications powered by LoRaWAN have minimal costs and battery performance receives a boost. NB-IoT services are synchronized and they are provided over licensed frequency bands, the costs for frequency band licensing is significant — with the per-MHz cost being >$500. Telecom operators have the option of deploying NB-IoT in guard bands, in 4G LTE spectrums, and of course, in a standalone network.

Both LoRa and NB-IoT provide coverage in the 10 km–15 km range. However, NB-IoT works best in sophisticated urban locations, and its performance is not up to the mark in suburban or rural areas (practically any place that does not have strong, glitch-free 4G coverage). Since LoRaWAN does not rely on cellular data or wifi for functioning, its coverage remains relatively steady across all types of locations.

Note: The LoRa base stations can be built at a fraction of the cost associated with the 4G-LTE base stations necessary for the deployment of NB-IoT. The lower investments required for LoRa works in its favour in a big way.

Because NB-IoT is a cellular-grade wireless technology the chips are more complex. That means users get the high performance level associated with cellular connections, but at the cost of more complexity and greater power consumption.

Advantages of NB-IoT are,

• The coverage would be very good. NB-IoT devices rely on 4G coverage, so they would work well indoors and in dense urban areas.
• It has faster response times than LoRa and can guarantee a better quality of service.

Drawbacks of NB-IoT are,

• LoRa devices have longer battery life than NB-IoT devices.
• LoRa devices work well when they are in motion, which makes them useful for tracking assets on the move, such as shipments.
• Network and tower handoffs will be a problem, so NB-IoT is best suited for primarily static assets, like meters and sensors in a fixed location, rather than roaming assets.

4.3 LoraWan vs Zibgee

Specifications	LoraWan	Zigbee
Frequency Bands	863 to 870 MHz, 902 to 928 MHz, 779 to 787 MHz	868MHz, 915 MHz, 2450 MHz
Coverage distance	2-5 Km (urban areas), 15 Km ( suburban areas )	10 to 100 meters
Power consumption	lower compare to zigbee	low
Modulation technique	LoRa modulation (CSS modulation) , FSK or GFSK	LoRa modulation (CSS modulation) , FSK or GFSK
Data rate	0.3 to 22 Kbps (LoRa modulation) and 100 Kbps (using GFSK)	20 kbps (868 MHz band ) , 40Kbps (915 MHz band ) , 250 kbps (2450 MHz band)
Network Architecture	Consists of LoRa Gateway, servers and end devices.	Consists of LoRa Gateway, servers and end devices.
Protocol stack	Consist of RF, PHY, MAC, application layers	Consist of RF, PHY, MAC, network and security, application layers.
Physical Layer	Uses modulation scheme as mentioned above and incorporates error correction capabilities, It adds preamble for synchronization purpose, It uses PHY header CRC as well as entire frame CRC.	There are two physical layers viz. 868/915 Mhz (uses BPSK, raised cosine pulse shaping) , and 2450 MHz (uses OQPSK, half sine wave pulse shaping )
Applications	used as Wide Area Network	used as LR-WPAN i.e. low rate wireless personal area network
Standard / Alliance	IEEE 802.15.4g, LoRa Alliance	IEEE 802.15.4 (defines PHY and MAC), Zigbee Alliance (defines network, security and application layers)

Advantages of Zigbee

• Setting up the network is very simple and easy.
• It does not have a central controller and loads are distributed evenly across the network.
• It is easy to monitor and control home appliances from remote.
• It will take the place of existing Infrared technology based devices. This will save cost of battery replacement as zigbee uses lithium battery which lasts long.
• The network is scalable and it is easy to add/remote zigbee end devices to the network.

Disadvantages of Zigbee

• It requires knowledge of the system for the owner to operate zigbee compliant devices.
• It is not secure like a wifi based secured system.
• Replacement cost will be high when any problem occurs in zigbee compliant home appliances.
• Like other wireless systems, zigbee based communication is prone to attack from unauthorized people.
• The coverage is limited and hence can not be used as an outdoor wireless communication system. It can be used in indoor wireless applications.

Is LoRa(WAN) better than its competitors?

Are LoRa and LoRaWAN better than other technologies (NB-IoT, Sigfox, etc.)?

• LoRaWAN has the benefit of being an alliance with an Open approach instead of a proprietary one.
• In a June 2016 blog post Cisco’s Tony Shakib announced several new Internet of Things solutions, including for the Cisco solution for LoRaWAN offering.

LoRaWAN is the most adopted type of LPWAN, and promises ubiquitous connectivity in outdoor IoT applications, while keeping network structures, and management, simple.

5. Applications and future of LoraWan technology

Smart City: LoRa WAN will be inevitable technology in future smart city applications together with Internet of Things like:

• Smart lighting
• Air quality and pollution monitoring
• Smart parking and vehicle management
• Facilities and infrastructure management
• Fire detection and management
• Waste management

Industrial Applications: LoRaWAN is suitable for a wide range of industrial applications.

• Radiation and leak detection
• Smart sensor technology
• Item location and tracking
• Shipping and transportation

Smart home applications: In future, billions of smart devices and home appliances will be connected to the internet.

• Enhanced home security
• Home automation for IoT enables smart appliances

Healthcare: LoRa is one of the best solutions for connecting healthcare devices efficiently

• Health monitoring devices and management
• Wearable technology

Agriculture:  LoRa technology can be used in smart agriculture and farming applications.

• Smart farming and livestock management
• Temperature and moisture monitoring
• Water level sensors and irrigation control

In future, our global, national and regional networks have to support billions or even trillions of devices. LoRa can play a significant role for providing a smart, low cost and highly efficient network for future applications. It has an association of more than 400 companies globally to contribute, improve and implement smart networks for future needs.

6. Typical products

6.1 Digital baseband chip of Semtech

Source: semtech.com

6.2 Micro chip SAM

Source: eletimes.com

6.3 Rugged gateway

Source: proesystech.com

6.4 LoraWan sensor of Daviteq

Source: daviteq.com

7. LoRa and LoRaWAN adoption trajectory in the IoT space?

• LoRaWAN networks, using the LoRaWAN protocol, are offered by over 70 network operators and there are LoRaWAN IoT deployments in more than 100 countries (private ones included).
• LoRa and LoRAWAN, has become the main non-cellular LPWAN ecosystems and solutions. It has a strong ecosystems of hardware vendors, developers, partners, IoT platforms, system integrators, IoT technology/solution vendors and telecommunication providers.
• LoRaWAN and LoRa are already widely available in several European countries, Asia-Pacific, Australia, and the US. On June 30th, 2016, The Netherlands became the first country in the world to have a nationwide LoRa network for Internet of Things applications.
• io, has developed a LoRaWan cloud, and is present in over 70 countries, including Russia, China, a large part of South America and several African countries.

8. Conclusion

In recent years there have been many researches on the development of IoT, which has led to its improvement. With the rapid increase of IoT devices and applications like, smart power grid, e-Learning, Smart cities, Healthcare, and environment protection, the revolution of the LoRaWAN technology is a powerful solution in order to help in solving the IoT challenges and obstacles. The details of LoRaWAN characteristics were illustrated and we conclude that LoRaWAN network technology has a powerful imprint in improving the near future IoTs devices and networks hence it has some excellent characteristics like, High QoS, Flexibility, Deployment, Scalability, Throughput, and Security.

We can consider LoRaWAN as a revolution created for IoTs world. If you are interested in more details or have any questions regarding the article, please contact us at info@daviteq.com