What is LoRaWan®?

LoRaWAN® is the communication protocol that functions on top of the physical LoRa layer. It is an optimized LPWAN developed by Semtech. Its nodes are asynchronous and only communicate when they have data ready to send. This makes LoRaWAN® incredibly energy efficient, which is a key requirement for many IoT networks with remotely located devices. Its physical layer, LoRa, relies on chirp spread spectrum modulation (CSS), which allows for long range communication within LoRaWAN®. LoRaWANs combination of long range data transmission, whilst maintaining low power consumption of its nodes makes it an ideal solution for many IoT- and M2M-enabled networks.

The Difference between LPWAN, LoRa and LoRaWAN®

LPWAN

LPWANs (Low-Power, Wide-Area Networks) will likely support a large portion of billions of IoT devices. LoRaWAN® is a type of LPWAN that is optimized for battery lifetime, range, cost and capacity.

LPWANs allow network operators to design IoT systems for use cases that specifically require IoT-enabled devices to send small amounts of packet data in intervals over remote networks spanning over many kilometers. These devices are likely located in remote locations and thus need to reliably function without much manual maintenance, such as swapping their batteries, in order to be feasible

LPWANs achieve these requirements by allowing IoT devices to only send small packets of data (such as status updates, reports, different types of sensor readings, etc.) infrequently. The transmission of this data is either triggered externally by the network or by a pre-programmed interval within the device. With the conception of cellular LPWAN, there is now much more potential and flexibility regarding the “wide-area” and “low-power” aspects of this networking technology.

When setting up an LPWAN there are several crucial factors a network operator should consider before basing their entire IoT infrastructure around this technology:

• Network architecture
• Battery lifetime or low power
• Range of communication
• Longevity & frequency of maintenance required
• Network capacity (amount of nodes the network can support)
• Security of network
• One-way or two-way communication between devices and network
• Types of applications

LoRa and CSS

LoRa and LoRaWAN® enjoy a good reputation as the go-to-technologies for future IoT systems. Despite being well-known among operators of low-power wide-area networks (LPWANS) they are frequently confused with one another, as both terms are used interchangeably.

LoRa is the PHY (Physical – i.e. chip) layer or wireless modulation utilized in order to create a long range communication link between devices. While many traditional wireless systems use FSK (frequency shifting keying) modulation as their physical layer, as it is power-efficient, LoRa relies on CSS (chirp spread spectrum) modulation. CSS features the same low power consumption as frequency shifting keying modulation, however it also significantly improves the transmission range of its devices.

Chirp spread spectrum modulation has been popular with military and space communication for decades. Two industries that rely heavily on low-power, long-range communication and resilience to interference

LoRa is a low cost implementation designed for commercial usage. It utilizes spread spectrum modulation, and more or less a proprietary version of CSS. LoRa sacrificed data rate for additional sensitivity within a dedicated channel . LoRa has a variable data rate, which allows the network operator to trade data rate for range or power and thus optimize network performance at a constant bandwidth based on their needs.

LoRaWAN®

LoRaWAN® is the communication protocol/data transfer layer (also known as MAC layer protocol) and the system’s architecture for the network that lies on top of the physical LoRa layer. LoRaWAN®, as the network architecture and protocol, has the most influence on battery lifetime of a gateway or node, its network capacity, its security, and the range of applications used within the network.

How LoRaWAN®’s network architecture differs

As of right now, most network deployed are based on a mesh network architecture. In a mesh network, dedicated end-nodes relay the information of other nodes (gateways) in order to increase both cell size and communication range of a network (much like a WiFi extender or repeater in a home network). While this undoubtedly increases range, there are many trade-offs: It reduces network capacity, battery lifetime (as nodes have to receive and forward information) and increases overall complexity, thus limiting flexibility.

In a LoRaWAN® network, gateways are not dedicated to specific nodes. Instead, data sent by a node is usually received by multiple gateways. Each of these LoRaWAN® gateways will forward the received data packet from the node to the (cloud-based) network server. So all the complexity of sorting out redundant or duplicate data packets, performing security checks or adjusting the data rate is pushed to the network server, which preserves the battery life of the nodes and the gateways. Thus, if a node’s location is changing, there is no need for a handover between two gateways. This is a crucial feature for many IoT systems used for tracking assets. (i.e. Supply chain management, tracking equipment/machinery, etc.)

How LoRaWAN®’s “star” architecture and incorporation of the ALOHA method preserve battery life:

The long range “star” network architecture utilized by LoRaWAN® allows for the preservation of battery lifetime. In a LoRaWAN® network, the nodes are asynchronous and only communicate when they have data ready to send (this can be triggered externally or internally by a pre-programmed interval/schedule). This protocol is also known as the ALOHA method: It is a random access protocol that prioritizes all nodes equally. It allows a node to transmit its data whenever it desires. If a collision with another node’s data transmission takes place, the node will wait and attempt to retransmit its data to the gateway after some time until the transmission is successful.

In a traditional synchronous mesh network (i.e. cellular), nodes always have to be in standby mode and power up frequently in order to synchronize with their network and check for new data packets. This constant need for synchronization consumes a lot of precious energy and is the most limiting factor to battery lifetime.

LoRaWAN®s network capacity
Gateways of a long range “star” network must boast a high capacity in order to make them viable. They need to be able to receive messages from a high volume of nodes. Using adaptive (flexible) data rate and multichannel transceivers in the gateways (to be able to receive simultaneous messages over multiple channels) are crucial measures to achieve a high network capacity within the LoRaWAN® network. There are a handful of critical factors that affect the network capacity, such as: amount of channels, payload length, data rate and interval of a node’s data transmission events.

Unfortunately many details about the inner workings of LoRa and LoRaWAN® are still unknown. Semtech, the proprietary owner of LoRa, keeps its lips sealed on exact specifications of the architecture.

Semtech and its LoRa Alliance

The LoRa alliance was founded by LoRa’s proprietary owner, Semtech, which is also responsible for the maintenance of this alliance. Most members of this alliance are either privately held companies, public institutions, that understand the potential benefits of IoT systems based on LoRaWAN® (or LPWAN in general) or authorized LoRaWAN® gateway manufacturers. Most companies and institution on the LoRa alliance’s member list are already heavily invested in industries that already or will greatly benefit from LoRaWAN®-based IoT systems, such as:

• Smart Environment
• Industrial IoT (i.e. Manufacturing)
• Smart Agriculture
• Smart Buildings / Facility Management
• Smart Homes (i.e. Building automation)
• Smart Cities
• Smart Utilities (i.e. smart grid management)
• Transportation & Logistics (i.e. supply chain management)

Most of these companies share a common interest: To advance the development of LoRaWAN® and other LPWAN-based systems as fast as possible in order to make their deployment commercially viable as soon as possible. On the LoRa alliance’s official website, members are categorized, as either Sponsor, Contributor, Adopter or Institutional.

LoRaWAN®-certified Gateways

LoRa-enabled nodes are not gateway-specific. This means, that consumers wishing to install IoT systems based on LoRaWAN® can deploy any device that is LoRaWAN®-certified (i.e. certified by Semtech) and can thus rely on the gateways’ ability to perform tasks that are crucial to M2M/IoT-enabled systems, such as maintaining low power consumption and transmitting data over a long range. A single LoRaWAN®-certified gateway has a range that can cover entire cities or hundreds of square kilometers.

While the deployment of LoRa and LoRaWAN® may seem futuristic to some, many gateways from a wide range of manufactures are already on the market, ready to feed your network with data provided by nodes. Many of these gateway manufacturers are already renowned for their many of their networking products within the tech space. Some of the leading LoRaWAN® products are developed by companies, such as: Cisco, Kerlink, The Things Network, Arduino or Raspberry Pi. While these devices have been deployed in over 100 countries, it is not always easy to find the ideal gateway for one’s needs as they all vary greatly in terms of capacity and configurability.

As mentioned previously, LoRa is proprietary. Companies that want to benefit from Semtech’s technology must buy LoRa-certified chips or gateways to connect to the LoRaWAN® network. From a large-scale manufacturing perspective, this is a major barrier for the efficient mass production of these gateways. If an IoT/M2M systems operator needs a reliable LoRa chip, they will need to become a client of one of Semtech’s authorized partners and licensees (all of which are part of the LoRa alliance).

LoRaWAN® in IoT

LoRa & LoRaWAN®’s unique properties makes them likely the ideal solution for most IoT & M2M applications, as these systems require small data rates to be transmitted over long distances or more remote, hard to reach locations, such as tunnels, or concrete-dense, urban environments. Battery life and maintenance is another crucial factor. LoRaWAN® is the answer to these demands, as it allows for the long-range transmission of data while maintaining low power consumption. It is very likely that all industries that already incorporated IoT and M2M into their day-to-day operations, will benefit from LoRaWAN in the near future.

The primary feature that makes LoRa stand out is its use of CSS (chirp spread spectrum) technology. CSS utilizes linear wide band frequency modulated chirp pulses to encode information. The LoRa platform achieved a record-breaking data transmission distance in 2017: A LoRaWAN® packet was received at a distance of 702 km. Semtech claimed that a single LoRa station can interact with sensors over 24-48 km away in rural, concrete-heavy areas.

References

https://lora-alliance.org/member-directory
https://www.link-labs.com/blog/what-is-lorawan
https://internetofthingsagenda.techtarget.com/definition/LPWAN-low-power-wide-area-network

https://www.seeedstudio.com/blog/2019/11/18/lora-and-lorawan-for-arduino-and-raspberry-pi/
https://www.hindawi.com/journals/wcmc/2018/3982646/
https://www.researchgate.net/publication/320898475_IoT_devices_and_applications_based_on_LoRaLoRaWAN

https://www.rfpage.com/applications-future-lora-wan-technology/
https://www.i-scoop.eu/internet-of-things-guide/lpwan/iot-network-lora-lorawan/
https://www.researchgate.net/publication/3867801_Spread_spectrum_communications_using_chirp_signals
https://www.researchgate.net/publication/333701390_Investigating_Theoretical_Performance_and_Demodulation_Techniques_for_LoRa#pf6