Can Sub-1GHz WiFi Solve The IoT Connectivity Issues?

The new IEEE WiFi standard 802.11ah using the 900MHz band could be the solution for low-power wireless data at urban networks, large corporate campuses, hospitals, universities, and other large facilities that need ubiquitous WiFi connectivity for a large number of sensors, low-power communications, smart meters, and other connected devices.

802.11ah could solve many problems with deploying large-footprint WiFi networks by allowing a significant number of devices, providing power saving services and long distance to the access point (AP).

A typical 802.11ah access point could associate more than 8,000 devices through a hierarchical ID structure within a range of 1 km, making it ideal for areas with a high concentration of sensors and other small devices, such as street lamp controllers and smart parking meters. It can use the 900MHz band (license-exempt) with high reliability because of the limited use of the sub-1GHz band.

The 802.11ah standard also includes new PHY and MAC layers, grouping devices into traffic indication maps (TIMs) to accommodate small units (such as sensors) and machine-to-machine (M2M) communications.

The PHY layer will allow devices and APs to operate over different sub-1GHz ISM bands, depending on the country regulations: 863-868 MHz in Europe, 902-928 MHz in the US, and 916.5-927.5 MHz in Japan. China, South Korea, and Singapore also have specific channels.

The 900MHz band is currently used in Europe for GSM 2G cellular service (the US uses the 950MHz and 1,900MHz bands). Though most carriers have moved to the faster 1,800 MHz and 3G UMTS, many devices still are using 900 MHz. Unfortunately, that requires the segmentation of devices for different regions, but that is already the case for most M2M communications and small sensors.

The European Union is trying to define the upcoming 5G standard as a mix of old and new wireless technologies. It's no longer possible to rely only on some forms of cellular data (GPRS/EDGE, HSDPA, LTE) to communicate with the 50 billion connected devices expected by 2020. Solutions such as WiFi offload, WiMax, 6LoWPAN, Zigbee, or sub-1GHz proprietary protocols also will provide the connectivity needed.

That's why the European Commission is proposing to use the 700MHz band for low-power, long-range, wireless broadband. The famous "digital dividend," resulting from the move to digital TV, made available a large part of the 700MHz band to be used for wireless data.

The US decided to auction that part of the spectrum in 2008. It was mostly allocated to AT&T and Verizon to launch LTE services.

Since the digital dividend Block C (22 MHz bandwidth 746-757 and 776-787 MHz) is declared open access, it could also be used for low-power WiFi in a way similar to the 802.11ah standard.

Google has filed a patent for the utilization of a sub-1GHz transceiver, mostly using frequencies in the ranges of 6.765-6.795 MHz, 26.957-27.283 MHz, 40.66-40.70 MHz, 433.05-434.79 MHz, 868-870 MHz, and/or 902-928 MHz for data transmission. Obviously, Google is looking forward to exploit the sub-1GHz spectrum for massive adoption of IoT and M2M devices.

While many players are fighting to control the communications standard for the IoT, it's clear to me that many connectivity options will co-exist. The 50 billion connected devices expected by 2020 will need many options, depending on the location, speed, and amount of data they'll use. A single protocol won't suffice.

Article first published as Sub-1GHz Wireless: The Low-Power WiFi Solution on Network Computing

GSMA Wants IoT Devices Connecting Via Embedded SIMs

Most outdoor sensors for utilities and city services are using M2M (machine to machine) solutions based on cellular networks. That poses a challenge to developers because they need to negotiate agreements with several cellular carriers in each market. Also the size of the SIM (subscriber identification module) cards limits the possibility of making smaller sensors and other connected devices.


When Amazon introduced the Kindle 2 international version in 2009, it was shipped worldwide with an AT&T international SIM, allowing users to shop the Amazon store and download titles almost anywhere in the world. That made sense to Amazon because people don't use the Kindle to browse the web, and they could offset the cost of the data charges with the book prices.

But millions of sensors sending continuous data to servers are another issue. It is not economical to fit everyone of those with an international SIM, or even a local one. Many other solutions are now being tested, including the upcoming 700 MHz 802.11ah standard. But, as of today, cellular data is the only solution already deployed and ready to use.

The GSMA -- the European mobile operators' organization that puts on Mobile World Congress and whose members includes most of the world’s cellular operators -- has created the Embedded SIM working group, which already includes cellular carriers and system developers. At this moment AT&T, China Mobile, China Unicom, Deutsche Telekom, Gemalto, Giesecke & Devrient, Morpho, NTT DOCOMO, Oberthur, Orange, Telecom Italia, Telefonica, Telenor and Vodafone participate in the project.

Basically, the operators are proposing a specific nonremovable SIM that is embedded into the IoT sensors during manufacturing. The SIM can later be provisioned over the air with the subscription profile of the operator providing the network. The device could be later reprovisioned if the unit is moved to another location or the customer decides to use another provider.

“The number of mobile connected devices is expected to reach 11 billion by 2020, growth that will be led predominantly by advances in the M2M market,” said Alex Sinclair, chief technology officer, GSMA, in a press statement. “This level of growth will be heavily dependent on the adoption of a common, global and interoperable SIM provisioning and management architecture that enables the M2M market to flourish. The specification released today will have a significant impact on the M2M marketplace, as it will help provide lower operational costs and drive economies of scale.”

An additional benefit of embedded SIMs is durability. Standard SIM cards for mobile phones are designed to withstand certain conditions. Giesecke & Devrient is already providing Verizon Wireless with ruggedized M2M embedded SIMs to withstand more harsh environments, including extreme temperature fluctuations, vibration or high humidity, like those found in outdoor meters, automobiles, external security cameras and buoys.

Car manufacturers are also excited about the possibility. High end makers such as Audi and Mercedes Benz are already including global SIMs in some models, but the embedded SIMs can be the economic solution for their deployment in every vehicle.

“Without a globally recognized, standardized and harmonized connectivity solution the automotive industry will become unnecessarily complex and fragmented. As a car manufacturer an Embedded SIM that can be remotely provisioned is absolutely key for us in driving efficiency and simplicity and is to be welcomed. We thank the GSMA and partners for agreeing this specification,” commented Marcus Keith, project management Audi connect, in a press statement.

IoT and M2M systems are being reshaped now to accommodate the billions of devices connected. Since there is no way a standard will be set for their connectivity, every industry will need to make it as easy and cost effective as possible for developers, government agencies and users to connect the devices. Embedded SIMs, low-power WiFi, ZigBee, and other approaches will have to coexist in a crowded market. Which technology will be most used? Probably the most cost-effective and easier to implement.

Originally published as "Mobile Operators Want SIMs in Every IoT Sensor" on EE Times

Carriers Under Fire For Throttling and Deep Packet Inspection

The Federal Communications Commission recently filed a federal court complaint against AT&T for charging millions of customers for unlimited data plans and then restricting speeds.The reason the FCC took action is because AT&T failed to inform users that they might experience slow speeds after consuming a certain amount of data in their so-called “unlimited” plans.


We now have essentially an open war among carriers, regulators, and consumers about the way wireless data can be sold and used. While it is understandable that carriers need some forms of traffic management, they also need to be transparent when selling their data plans to users. Also, penalizing paying users for making the best use of their data plans should not be tolerated.

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