LoRa WAN IoT.... #Internet #LoRa #RemoteSensing #EmbeddedSystem #IoT #WAN #Network
With the blast of innovation in technology, gadgets and devices within past few years people have been thinking and researching about Internet of Things and how will it change this planet with millions and billions of devices connected together all the time. But this vision of connection of billions of devices has great amount of challenges. Devices like Bluetooth, Wi-Fi and BLE are not suitable for long range wireless communication, also cellular equipment’s and networks not equipped with this type of situation as they are not power efficient. All these technologies are also expensive.
IoT systems and application require low data to be transferred which require low power and lots of battery life so to tackle these challenges LoRa Alliance has developed a new technology called as LoRaWAN.
What is L0Ra?
LoRa Stands for LOng RAnge. It is a Low Power Wide Area Network (WAN) for long range communication which uses spread spectrum and chirp spread spectrum modulation techniques, designed specifically for IoT (Internet of Things). Both these techniques provide long range wireless communication and data transfer. LPWAN has great penetration and resilience and can be easily built, connected home, office, factory, refinery, or farm, any business country or region. It was first developed by Cycleo SAS and later on Semtech acquired it.
· Demodulate below noise threshold-30db better than frequency shift key.
· High sensitivity than frequency shift key.
· More resistant to interference, noise and jamming.
· Multiple signals can occupy same channel by creating virtual channels within same channel.
· Resistant to Frequency offsets, multipath, fading and also Doppler effects.
· Low power consumption.
Building LoRa Network:
LoRa network requires both hardware and software support.
In hardware LoRa needs devices, switches and gateways like typical Wi-Fi network. Gateways are easy and simple to implement just scan spectrum and capture data.
At software side LoRa needs firmware, network service and app.
LoRa modulation technique is implemented on physical layer of LoRaWAN. LoRaWAN provides the basics of IoT such as two-way communication, mobility and localization. The network re duplicates same packet when received by more than one gateways, gateways decrypts data packets like adaptive data rating(ADR), Than data is forwarded to application layer.
LoRaWAN network has a star topology having transparent Gateways which are connected to end devices. These Gateways are connected to network server via standardized IP protocols. End devices use single hop technique to communicate with gateways.
Types of Devices:
LoRa network is composed of end devices and gateways that are based on MAC layer. There are total of three classes of end devices in LoRaWAN. These are Class A, Class B and Class C. All Classes are bi-directional in nature.
Class A End Devices:
LoRaWAN data packet is divided into two transmission frames, uplink frame and downlink frame. In class A uplink frame consists of 1 slot and two downlink slots. Uplink is called when needed. This is random and follows ALOHA protocol.
Class B End Devices:
Class B devices have one extra slot during downlink period with two time slots as in Class A. This extra slot is after specified time and this time is set by gateway using beacon frame. This is how LoRaWAN indicates server when to talk to end devices.
Class C End Devices:
This class of end devices can hear all the time but not in transmission mode. This class of devices needs more power. Class C has the fastest data rate and lowest latency level.
LoRaWAN data flow is simple P2P (Point to Point) communication and Bi-directional. User logic is implemented according to need into server. Data flow and communication between devices and gateways is spread across different channels and flow rate. Data flow and rate don’t collide with each other and make a virtual channels to avoid collisions and increase capacity. To secure the data Flow multiple layers of security and encryption are added such as EUI64 on network and application layer and EUI128 at device physical layer. The following diagram show how the data of LoRaWAN flows through the entire network.
LoRa can be used in variety of applications some of them are:
· Water and Gas metering
· Street Lightning
· Smart Buildings
· Smart Parking
· Leak detection and irrigation
· Water level & flood management
· Fault management
· Smoke Detectors
· Smart energy & fast demand response
· Waste management
· Traffic management
· Long Range: 157dB to 168Db Link budget, greater than 15km range
· Ease of Deployment: Minimal infrastructure and concentrator with capacity
· Long Battery Life: Greater than 10 years of battery life, In RX mode -10mA, sleep mode less than 200Na
· Low Cost: Unlicensed spectrum, low infrastructure cost, low end node cost
· Standard: IEEE 802.15.4g
· Frequency Band: ISM band 868 MHz and 915MHz
· Capacity: One LoRa gateway handle thousands of nodes