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IoT Blog

LPWA: Fulfilling the Promise of Smart Cities

by Gus Vos, Chief Engineer, Technology Standards
Urban planners and city managers are excited by the promise of Smart Cities. As urban populations increase, there is more urgency to find efficient, cost-effective ways to meet increased demands on resources and infrastructure. The ultimate promise of Smart Cities is a single system of integrated, interoperable solutions. Imagine if a traffic accident captured on CCTV could trigger alarms that alert first responders, divert transit vehicles away from the area, change traffic lights to allow emergency vehicles quicker access – even increase street lighting levels so that public safety personnel can work more effectively.

Disparate technologies and lack of standards have made such integration efforts difficult. Cost, power consumption, coverage, and life cycle issues add to the challenge. Many Smart City applications, such as those for monitoring utilities, only need low data rates. This makes 3G/4G modules designed for high bandwidth and low latency applications expensive in terms of price and power consumption. As a result, low-power wide-area (LPWA) technologies designed to reduce cost and complexity have emerged to target such applications.

Some vendors have built proprietary LPWA products that use unlicensed bands; this offers some advantages when it comes to speed of development. However this gap has almost disappeared, in Q1’2016 the 3GPP standards organization ratified several LPWA technologies for use in licensed bands and recently several large mobile operators, chipset vendors, and modules vendors (like Sierra Wireless) have announced LTE-M commercialization early in 2017, so the wait is over. When it comes to proprietary versus 3GPP-compliant LPWA’s, large users and major solution providers have avoided proprietary solutions due to concerns over reliability in unlicensed bands as well as the limited ecosystem, which impacts global coverage, support, and scalability.

Sierra Wireless advocates 3GPP LPWA standards-based technologies because of:

Cost benefits: LPWA modules in general cost less per unit than full-feature cellular modules, but 3GPP LPWA technologies, such as LTE-M, are compatible with existing mobile networks and equipment. This means economies of scale from wider adoption – one factor that makes 3GPP LPWA-based solutions for Smart Cities less expensive in the long run.

Power consumption benefits: For Smart City applications where modules must rely on battery power, the technology must be designed to operate reliably for 10-15 years.   Studies have shown that the best power consumption is achieved when the device is in good coverage because the Smart City application can then quickly complete the required transaction and go to a low power sleep state. Given the high density of base sites already deployed in a cellular network, coverage will be better more often than for proprietary solutions which have much less dense base site deployments.

Reliability and coverage benefits: Smart City applications for utilities and infrastructure are often deployed underground or at remote locations where signal strength can be weak, creating reliability and battery life problems. Unlike proprietary solutions, 3GPP LPWA modules are compatible with existing mobile networks which as mentioned above have base sites deployed much closer together than proprietary deployments; as such, 3GPP LPWA modules are more likely to experience better signal coverage.

Longer life cycle benefits: When IoT deployments range from thousands to millions of devices, the cost of replacing these assets is non-trivial. Smart Cities need devices that are robust, low-maintenance, and supported by mobile network operators (MNO) decades into the future.  With 3GPP LPWA, Cities can be assured of ongoing compatibility with MNOs and of maintaining modules cost-effectively via OTA (over-the-air) upgrades – a feature lacking in some LPWA technologies.

To learn more about Smart Cities, 3GPP LPWA technologies, and LPWA for Smart Cities, contact Sierra Wireless or take a look at these Sierra Wireless resources: