There are dozens of wireless technology options for the Internet of Things (IoT), but only a few offer the broad coverage, increased security, and superior reliability that the industrial sector requires. The recently published standard from the IEEE designated 802.16s may be just the technology that some mission-critical users are demanding.
You may remember the 802.16 designation by its trade name, WiMAX. This broadband wireless metropolitan area network (MAN) technology was at one time competing with LTE for 4G cell phone adoption. It was implemented by Sprint but soon gave way to LTE as the dominant 4G technology. Yet, WiMAX is still around in various forms as it offers features and benefits that make it suitable for some essential applications.
This new standard was developed primarily for electric utilities with input from the Electric Power Research Institute (EPRI), the Utilities Technology Council (UTC), and the WiMAX Forum. One application is advanced metering infrastructure (AMI) backhaul that handles smart meter traffic from remote concentrators back to a central office. Electric substation data acquisition is another use. The standard also works with SCADA systems.
The standard also addresses other serious applications such as oil and gas pipelines, water and gas utilities, nuclear facilities, rail transportation, environmental monitoring, military, and homeland security. Aside from its superior benefits of security and reliability, the standard permits the network to be fully disconnected and separated from the public internet.
The 802.16s standard is based essentially upon the specifications of the older WiMAX 802.16e version. It uses OFDMA and time division duplexing (TDD) that does not require the paired spectrum of FDD LTE. It is designed to work at lower data rates using channel bandwidths from 100 kHz to 1.25 MHz. Modulation can be BPSK, QPSK, 16QAM, or 64QAM, but an adaptive modulation and coding scheme lets the system optimize the throughput depending upon local conditions. Encryption is the Advanced Encryption Standard (AES). Other features include a longer frame size to increase throughput, as well as a way to adjust the asymmetrical downlink (DL) to uplink (UL) ratio to optimize throughput for some common asymmetrical industrial applications.
While the original 802.16 standard was designed to be used in the 2 to 66 GHz range, the 802.16s version is adjusted to work at much lower frequencies since utilities and other industrial users do not typically have access to more the widely used broadband spectrum. But the utilities and other industries do have allocations for their own licensed spectrum. Some examples are 217-218 MHz, 406 MHz, 901 MHz, 1.4 GHz, or 3.65 GHz. The upper A block of the 700 MHz spectrum is also available.
The utilities simply wanted their own standard and did not want to rely upon standard cellular IoT carriers for their critical infrastructure. This new standard puts the utility in control. While the initial capital expenditure is high, the operating expenditure is lower. Furthermore, the utility controls the spectrum, security, reliability, and pace of upgrade, as well as the maintenance and repair.
One company making 802.16s gear is Full Spectrum, using its patented software-defined radio (SDR) technology. The firm’s FullMAX radios work on all licensed frequencies below 1 GHz, featuring high transmit power and software-configurable channel sizes from 50 kHz to 5 MHz. Otherwise, the radios are based upon the 802.16e standard with OFDMA. A typical FullMAX network uses the BS1000 basestation and FS4500 outdoor or Cobalt-Plus remote radios (see photos).
The 802.16s standard is clearly an alternative to the current choices for longer-range industrial IoT wireless technologies. Licensed spectrum is available if you need that extra security and reliability.