The Value of Information: Best Practices for Choosing a Wireless Network for Connecting the Internet of Things
Now that there are over 10 billion mobile devices and PCs connected to the Internet worldwide, the next evolution is taking shape . Whether it is called the Internet of Things (IoT), the Industrial Internet, or the Internet of Everything, the vision is relatively the same – achieve value by connecting billions of previously unconnected devices or objects to a network for the automation of insights that can be used to solve existing business problems, improve efficiencies, or create new business opportunities. Choosing a wireless network, which is often a machine-to-machine (M2M) network, to connect unconnected IoT objects can be challenging because there are many choices available, from cellular to unlicensed mesh, lightly licensed narrow band, and others. Plus, the requirements of connecting objects differs from the requirements for connecting mobile devices and PCs that require high bandwidth and high data rates. Though the data throughput requirements for these devices are often relatively low, there are other issues to consider. For example, objects connected within the Internet of Things are characterized by:
- Large numbers with sensitivity to price (both initial and recurring).
- Widely distributed across large geographic areas.
- Located in difficult radio environments, e.g. in basements, below ground, and in shielded environments.
- Require latency in near real-time, e.g. on the order of seconds, less than one minute.
- Require years of dependable battery operated power (since devices can be in hard to reach locations).
- Require an extremely secure network due to their critical nature or commercial value.
With these requirements in mind, outlined below are some best practices for choosing an IoT network.
1. Total Cost of Ownership: Due to the proliferation of the Internet of Things, larger numbers of assets are being connected. With each wave of IoT expansion, there is a 10x jump in the number of connected devices. Not surprisingly, price sensitivity increases – pushing the price point of new IoT connections to 1/10th the price of the previous wave. Networking platforms, innovation, and technology must keep pace in order to enable the IoT. The technology, deployed cost, and ongoing operating expenses must all achieve a total cost of ownership (TCO) that aligns to the price sensitivity of each successive IoT wave. Best-in-class technologies deliver low TCO with long range/high-capacity coverage, low maintenance expense, and high reliability.
2. Coverage: The range of a wireless link to reliably connect devices. The range is measured in meters from the access point (AP) and varies depends on the RF propagation environment. Factors, such as terrain, clutter type (e.g. urban, suburban, rural, etc.), interference, and local output power regulations determine the range capabilities of a specific radio.
The primary driver of coverage is link budget, which measures the ability of a wireless system to overcome obstacles to close a link. Link budget is driven by many factors, but at the highest level, there are three primary factors that contribute to link budget: transmit power, antenna gain, and receiver sensitivity. A good rule of thumb is to compare the receiver sensitivity to the thermal noise floor. A strong radio will have the ability to operate at negative signal-to-noise ratios well below this floor. Therefore, a lower link budget equals better coverage.
3. Capacity: The amount of data from device endpoints that a network AP can simultaneously serve and its measured aggregate application throughput (kbps). Coverage and capacity work in conjunction to drive a low number of APs to device endpoint ratios. Providing coverage for many devices without proper capacity is pointless; conversely, excess capacity without coverage to reach devices is equally pointless. It is the optimal mix of the two that delivers cost effective performance for a wireless network.
In discussing capacity, it is also key to differentiate between the single-link throughput, from a single endpoint to an AP, and the aggregate capacity of the AP serving many endpoints. The single-link throughput of a technology could be modest, but if there is a good multiple-access scheme, the aggregate capacity could be extremely high. Since most devices have low throughput requirements (e.g. grid transformers do not need to stream video) the aggregate capacity is the metric that matters.
The network topology and multiple access technique drive this required margin. With a star topology and a good multiple access technique, an AP can be safely operated at approximately 60 percent capacity.
4. Coexistence: Like all wireless devices, device-networking radios must be robust to interference and a propagation environment that is in constant flux.
Wireless communications technologies are connecting the world. A robust wireless platform will operate reliably even with increasingly crowded radio spectrum. A strong house is built with quality materials supported by a resilient structural frame anchored by a strong foundation. Similarly, the best wireless platform is constructed with quality from the ground up. Every layer of the communications technology must be designed to withstand increasing co-channel interference, and ensure reliable data transfer between the endpoint and the AP. A wireless protocol that demonstrates these features at every layer makes the underlying wireless medium, with all its interference and channel variation, perform at a level expected only in a wired environment.
5. Efficient Power Consumption: End devices connected to an IoT network, such as gas and water meters, fault circuit indicators, or other sensors are not continuously powered. However, because they are monitoring critical infrastructure and often located in hard to reach locations they must have a battery life that lasts greater than 10 years.
Power efficiency of end devices is driven by the wireless protocol. The key to efficiency is to minimize the time and power spent transmitting and receiving radio waves. This can be done using various techniques including fast acquisition (reducing the amount of time it takes to find the network and adaptive modulation) to minimize the amount of time needed to transmit the packet. In addition, the protocol should be designed such that the endpoint is in a low power “deep sleep” mode most of the time.
6. Security: To prevent malicious attacks, particularly those focused on critical infrastructure, IoT networks require proven and robust cyber-security across the network. A strong network should use a comprehensive strategy to deliver this information security, including:
- Prevention: Provide access control, mutual authentication, confidentiality, and high availability.
- Detection: Identify system breach attempts and alert operators.
- Recovery: Ensure the system degrades gracefully and continued operation even while under attack.
- Guarantees: Provide key security guarantees such as entity and message authentication, message confidentiality, limited anonymity and firmware upgrades.
Additionally, your IoT security should use National Institute of Standards and Technology (NIST) approved security algorithms that have greater than 20 years of life.
Making the Internet of Things a Reality
Though the vision of the Internet of Things is not a new concept, it is finally closer to becoming a reality because of advancements in low power, wide area wireless networking technology. Many of the networking technologies being proposed today were originally designed for applications that are significantly distinct from the requirements of IoT device networking. Consequently, they have serious limitations in scaling to a low bandwidth, widely distributed network with potentially tens of thousands of hard-to-reach devices. However, if companies follow the guidelines above to meet their connectivity needs, they will achieve a successful IoT network.
About the Author
Mr. Rasweiler has more than 18 years of engineering, sales and business development experience within the wireless communications industry. Since joining the company, he has been instrumental in developing and commercializing key partners including GE, SAIC, and Fountain Springs, which was On-Ramp’s first AMI deployment. His current focus areas include supporting the GE commercialization and launch activities, and market segmentation and entry strategy for Oil, Gas, and Electric markets. Prior to joining On-Ramp Wireless, Mr. Rasweiler was the CTO and VP Engineering for Arcadian Networks, where he was instrumental in developing and deploying one of the very first Smart Grid wireless networking systems – a currently operating statewide smart grid network in Minnesota. Prior to this, his wireless carrier experience includes various leadership roles at Nextel and Sprint, including Senior Director for the New York Area and Northeast Design leader. He has worked on a wide variety of domestic and international communications projects including the World Trade Center recovery effort, and the operation of Con Edison’s private radio network.
 10BN+ Wirelessly Connected Devices Today, 30BN+ In 2020′s ‘Internet Of Everything’, Says ABI Research, TechCrunch, May 9, 2013