LoRa Network Protocol and Long Range Wireless IoT

Basics:

LPWAN stands for Low-Power Wide Area Network

Current Issue: 2G Networks are being sunset (AT&T on January 1, 2017 with other major carriers to follow..) and are not fully suited to IoT applications due to battery life constraints.
- Next gen cellular proposals (LTE MTC) targeting IoT applications are not ready for deployments until 2018 so there is a current gap in the market .

LPWAN Benefits

• Generally uses unlicensed spectrum (868 MHz in Europe and 915 MHz in US for example)
• Range: From a few kilometers in dense urban areas up to 15-30 kilometers in rural areas
• Power: 10+ years of battery life (The device's power produced cannot exceed 10-25 mW, to comply with usage of ISM frequencies, and to limit data consumption and preserve battery life.)
• Radio Chipset cost: $2 or less
• Radio Subscription cost: $1 per device/ year

Additional Highlights

• LPWA most suited for on/off type applications with only a few messages per hour.
• 5-10x fewer base stations required than 3G/4G
• LPWAN capabilities will eventually be integrated into 5G service base stations

How do they work? Each standard uses a different technique to maximize range while minimizing transmission power. Sigfox uses a well-known modulation technique, but transmits slowly in a very narrow band of spectrum to maximize signal penetration. LoRa radios use a modulation technique that can find signal well below the noise floor. Ingenu uses their own novel form of spread spectrum modulation.

Put simply, these radios do some crazy math.

In fact, most of the underlying radio technology here isn’t new — the techniques for encoding signals were invented decades ago. What’s new is that the math has been committed to silicon, and is being produced in scale. So now you can buy a radio chip for a few bucks and add it to any device.
Daniel Conrad

LoRa

LoRa: PHY layer
LoRaWAN: MAC, NWK, & APP built on LoRa

LoRa is a patented ( EP2763321 from 2013 and US7791415 from 2008 ) spread-spectrum radio modulation originally developed by Cycleo (Acquired in 2012 by Semtech)

Semtech owns the LoRa IP, but have licensed the IP to other chip manufacturers like STMicro in 2015 in 2015.

 

Semtech’s LoRa chips transmit in the sub-gigahertz spectrum (109MHz, 433MHz, 866MHz, 915MHz), which is an unlicensed band that has less interference than others (like the 2.4 GHz range used by Wi-Fi, Bluetooth, and other protocols). At those frequencies, signals penetrate obstacles and travel long distances while drawing relatively little power -- ideal for many IoT devices, which are often constrained by battery life.

Within the sub-GHz spectrum, LoRa chips use a spread-spectrum strategy to transmit at a variety of frequencies and data rates. That allows the gateway to adapt to changing conditions and optimize the way it exchanges data with each device.

Semtech produces transceiver chips for devices to be connected (nodes), and gateways to connect them. A single gateway can communicate with several hudred thousand nodes up to 20 miles away in unobstructed environments, and even in a city can penetrate buildings to achieve a range of several miles. End-nodes can remain operational for a supposed 10 years running on two AAA batteries (drawing 10mA for the receiver, under 200nA in sleep mode).

The LoRa Alliance

An industry collaboration focused on promoting LoRa was unveiled at the 2015 Mobile World Congress in Barcelona. The LoRa Alliance is a non-profit, open membership organization. Founding companies include technology suppliers and telecom operators:

Tech Suppliers	Telecoms
Actility Cisco Eolane IBM Kerlink IMST MultiTech Sagemcom Microchip Technology	Bouygues Telecom KPN SingTel Proximus Swisscom FastNet (part of Telkom South Africa)

Cellular

EC-GSM-IoT for 2G networks
LTE-MTC (LTE for machine-type-communications)
NB-IoT - Can use both 2G and 4G spectrum
LTE-Advanced Pro, 5G

Weightless

Weightless-W (Original - Whitespace focused)
Weightless-N (Born out of NWave’s technology.)
Weightless-P, (Born out of M2COMM (Platanus) technology

Weightless Standards Comparison

RPMA - From Ingenu

Created by Ingenu (formerly OnRamp Wireless) their RPMA LP-WAN (random phase multiple access) uses 2.4 GHz ISM so that it avoids some of the geographic differences compared to other solutions using license free bands.

RPMA’s uplink capacity cann support up to 2 million devices per tower.

NB-Fi (Narrowband Fidelity) - WavIoT

• "NB-Fi LPWAN technology covering a full stack of OSI model layers from physical PHY to application APP. Full duplex gateways based on bi-directional SDR principles accompanies with 3 × 120-degree sector antennas and self-designed SDR receivertransceiver result in the sensitivity of -154 dB and ensure a total link budget of up to 194 dB. The effective distance proven in numerous use cases is more than 50 km in the countryside and 16 km in the urban area."
• "Open Standard"
• Supporting radio hardware and compliant MAC architectures in 915 MHz, 868 MHz, and 433 MHz ISM bands, as well as other sub-GHz license-free spectrum.

Additional:

CyNet, Silverspring Starfish, Dash7, Wi-Fi HaLow, Telensa Ultra-Narrow-Band