The Battle for Bandwidth: IoT wireless networks

IoT wireless networks: The market for Low Power Wide Area Networks appears to be a standards’ battlefeld. Sigfox, LoRa and NB-IoT are among the most-named technologies, and users are waiting for a winner  to emerge. Perhaps a better strategy is to choose the network that best fits the IoT-solution and not to wait.

A disruptive technology like the Internet of Things requires new standards in bandwidth technologies. According to the Vodafone M2M Barometer 2015, high costs are the third most common barrier, behind security and privacy, to the increased use of Internet of Things and M2M solutions. The distribution of many solutions with IoT wireless networks requires the availability of longer battery life, cheaper devices, lower deployment costs, and better coverage than can be established with M2M networks that are currently available.

Low power, wide area (LPWA) technologies have emerged to fill the gap between cellular mobile and short range networks, such as Bluetooth or Wi-Fi. The resulting fight for market space has become a battlefield for several standards. What is LPWA? Low power, wide area technology is a new type of connectivity standard designed to complement existing telecommunications networks and link specifically with constrained IoT devices. LPWA networks operate on a different part of the wireless spectrum, with a lower bandwidth, enabling access to wide area communications at low cost and with low power consumption. The technology is used for long-range communications in urban areas enabling smart city solutions, such as lighting, metering, or grid monitoring. It is also a good option for applications in isolated areas where long battery life is particularly useful, like smart agriculture solutions or pipeline monitoring. The networks aren’t meant for devices used in areas with constant access to local Wi-Fi networks and power supplies, and can’t be used for advanced or critical IoT solutions which require high data rates and reliability, such as connected cars.

Do not expect a unique wireless technology to conquer the market, neither NB-IoT nor other LPWAN alternatives like LoraWAN or Sigfox. There will always be fragmentation as each technology has its own pros and cons.

_{Alicia Asin, CEO and cofounder Libelium}

 

The most prominent standards in the LPWA feld are Sigfox, NB-IoT, and LoRa. Smaller emerging standards include Ingenu, Weightless-P, or Waviot. In order to compare these LPWA technologies, it is essential to understand the background of each standard, their technological aspects and the business models behind them.

Sigfox, a French company founded in 2009 with the intent of creating a global long range infrastructure, was the first organization to recognize the gap to be filled by LPWA and can therefore be considered the prime mover. As a startup, it has collected $309m in funding, its latest two rounds achieving record contributions of more than $100m (Series The BATTLE for D, February 2015) and $160m (Series E, November 2016). The Sigfox network has rapidly spread and is currently being deployed in roughly 30 countries, of which 12 have full coverage already. The company recently announced 20% coverage in the US, where over 100 cities were connected in just one year. Sigfox acts purely as a network owner and operator and leverages the unlicensed broadband spectrum. The company sets up its own base station antennas and occasionally cooperates with mobile network operators (MNOs). All data from installed devices passes through Sigfox servers for transfer to the customer’s network.

LoRa/LoRaWAN is an unlicensed spectrum LPWA standard, engineered by chip company Semtech, following its acquisition of the Long-Range IP provider Cycleo in 2012. The name LoRa, an abbreviation for ‘long range’ can be considered the physical layer or wireless module, and LoRaWAN is the communication protocol and system architecture for the network. The LoRa Alliance was founded in 2014 and is an open, non-profit association aiming at the worldwide standardization of LPWA networks to enable the Internet of Things. LoRaWAN and LoRa are widely available in Europe, and are being increasingly used in several countries. In February 2016, the number of members passed 200. Compared to Sigfox, LoRa doesn’t cover quite as much ground but is hot on its heels despite being initiated three years after Sigfox.

NB-IoT Narrow-Band IoT, or NB-IoT, is the newest standard in the LPWA field. In comparison to Sigfox and LoRa it covers a licensed-spectrum LTE band. The narrowband radio technology was specified by the Global System for Mobile Association (GSMA) within its 3rd Generation Partnership Project (3GPP) for implementation in the current LTE and GSM infrastructure. The aim of the GSMA NB-IoT Forum is to launch commercial solutions in 2017 but Deutsche Telekom was the first mobile network operator to deploy a field implementation pilot scheme in 2016. The trial in Germany was conducted with Huawei equipment using its version of NB-IoT. Deutsche Telekom competitor Vodafone has also completed first tests and announced the pending launch of its first live commercial NB-IoT networks in Germany, Ireland, Spain, and the Netherlands for the first quarter of this year.

Battleground 1: Technicalities

The Sigfox network runs on unlicensed spectrum of 868MHz or 902MHz, with a bandwidth below 100kHz and data rate of less than 0.1kbps, which translates into 12 bytes upstream and eight bytes downstream per payload. The connection is designed for low frequency applications sending up to 140 messages per day. As the hardware used for Sigfox modules leverages low energy consumption, it is mainly used in remote, hard-to-reach areas with no available power supply. One example of a Sigfox network implementation is the use of small modules in ‘smart’ garbage cans in Barcelona which report when a bin is full and ready for collection.

While uploads, or endpoint-to-basecommunications, are generally effective, downloads (base-to-endpoint) are less so. All modems and network stations have unique Sigfox IDs, which get transferred along with each message sent to serve as device authentication, but details of transmissions are not recorded by the devices. The modem transmits every message three times on three different channels but, with no awareness of in-range network stations, information is lost if there is no online base station to receive the message. While the network can cover several kilometers, it is theoretically possible that other systems using the same frequency could jam the network if positioned near a Sigfox device. The low data rate, and therefore higher transmission times, could raise the probability of collisions with other devices in the same network causing incomplete data transmissions.

LoRa also runs in unlicensed spectrum with a bandwidth under 500kHz, for which Semtech and other LoRa Alliance Members offer chipsets for unidirectional (860-1020MHz) and bidirectional (860-960MHz High Band or 169-510MHz Low Band) devices. It can provide a considerably higher data rate of 0.3 – 50kbps and both uploads and downloads are effective with bidirectional bandwidth. While Sigfox may be appealing to developers who are merely interested in sending/receiving small messages, the main advantage for LoRa lies in its effective downloads. If a device not only reports events but also triggers actions, communication needs to happen in both directions. This can be the case for smart farming solutions that measure soil condition a few times per hour and can also activate watering systems when necessary. The spectrum of NB-IoT is licensed LTE inband guard-band standalone, with its bandwidth set at ~200kHz at a data rate of up to 170kbps for downloads and up to 250kbps for uploads. This standard lies above LoRa and way beyond what Sigfox offers. The higher capacities of NB-IoT means shorter battery life and higher costs. A typical application would be using NB-IoT for smart grid monitoring, which requires higher data rates and frequent communication to grant near-realtime insights. NB-IoT operates in a spectrum shared with LTE and GSM networks so deployment does not require a new infrastructure. However, some basestations will need to be upgraded.

Battleground 2: Go-to-market strategies

The main benefit of Sigfox is the low cost of devices as well as no roaming costs globally which means the entrance barrier to the technology is set fairly low.

Chips from a wide number of vendors will keep hardware costs down, and the company offers its services as a subscription contract. The pricing model depends on key variables such as the total number of connected devices, the maximum volume of messages sent, and the duration of the subscription. Typical costs amount to between $1 and $7 per object per year.

I see Sigfox as a basic enabler of the world‘s IoT applications, similar to the invention of mobile phone app stores. Our technology is a perfect fit to the IoT requirements: a strong community, driving various innovative apps and industrial applications.

_{Aurelius Wosylus, Director of sales and partners Sigfox}

The LoRa Alliance allows for any IoTplayer to become a member. Network specifications are open and can be downloaded from the LoRa Alliance website. The main idea behind the open business strategy is to inspire rapid adoption and ensure network setup is not limited to mobile network operators. Anyone can set up their own private networks using a LoRa base station. For example, US startup Cattle Traxx sets up LoRa networks specifcally for livestock monitoring. LoRa networks are also being planned by telecommunications companies like Softbank in Japan, Comcast in the US, or Orange in France, potentially reaching 200 million cellular users. Despite all openness concerning network specifications, only licensed chipsets may be used for LoRa transceiver modules. Initially, Semtech was the sole supplier of choice but other vendors, like Microchip Technology and STMicroelectronics, have now been added as licensed partners. Pricing varies depending on network provider. As an example, SK Telecom completed a nationwide roll-out of LoRa in South Korea in July 2016, claiming it now reaches 99% of the country’s population. The costs for monthly flat rates vary between $0.30 and $1.75, depending on the required data use. The next few years will show how well NB-IoT will be adopted. Being backed by the GSMA and several mobile network operators, NB-IoT has a very powerful group of supporters behind it. So far, along with Deutsche Telekom and Vodafone, several mobile network operators have announced plans to launch this technology. There won’t be any possibility to launch private networks using NB-IoT, users will depend on growing support among public operators. In contrast to Sigfox, there will be the possibility of more than one network operator offering NB-IoT connectivity, thereby creating additional competition.

IoT wireless networks: And the winner is…

All three technologies have their own advantages in specific situations. The various LPWA specifications cover differing needs and the most suitable depends on the technicalities and the setup of each implementation. Sigfox is probably the best solution for the most basic IoT devices, that don’t need to do much more than occasionally send small messages and don’t need to receive much information. They can run the longest on battery and hardly ever need attention. LoRa will work for any device that requires long battery life, and needs to send and receive larger data packages than a Sigfox device. NB-IoT is the future for anything that requires higher data rates and for which battery life isn’t the biggest consideration. Any organization considering the use of a LPWA standard should first define precisely what it requires from the technology and that will clarify which standard fits best.

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