MAS Radio: A critical but aging link for SCADA

For years, Multiple Address (MAS) radio has been a popular solution used by utilities to reach and aggregate remote terminal units (RTUs). It is widely used by electric utilities, the oil and gas pipeline industry, water and wastewater systems, and railroads – allowing communications with remote devices that are critical to the reliable and safe operation of the systems which they are part of.

The typical MAS radio system consists of a master radio that communicates with multiple remote radios on paired transmit/receive frequencies in the 900 MHz band. Transmit powers of 5 watts on masters and 1 watt on remotes, coupled with the use of directional antennas, allow reliable coverage out to 10 miles (and often well beyond) in many applications. Although data rates are limited to 4.8 kbps or, with reduced coverage, 9.6 kbps, the systems were more than adequate for the traditional SCADA applications they typically support.

During the early 1980s, the FCC allocated specific 25 kHz wide channels in the 928-929 MHz and 952-953 MHz bands for use by MAS operations. During this same timeframe the importance of SCADA connectivity to remote sites was of growing importance. In this environment there was a fairly widespread adoption of MAS solutions by many utilities.

If we fast forward 30 years, a lot has changed. With their narrow banding initiative to drive more efficient use of spectrum, the FCC requires new MAS licenses to use 12.5 kHz channels. (An earlier proposal to "un-grandfather" existing 25 kHz MAS licenses was put in place in 1990 and later rescinded in 1993.) The industry is moving beyond simple visibility and control of remote sites because more data and more timely data allow increased efficiency and reliability of infrastructure. IP connectivity is an increasingly important component of many utility telecom strategies. Cybersecurity, physical security, and the potential for hacking or interruption of service have all grown in importance. While simple connectivity was adequate in the 1980s, today there are numerous applications (including high bandwidth applications such as video surveillance) that would also be desirable at remote sites.

The bottom line is that there are significant portions of the existing MAS infrastructure that are critical, yet the technology in place on many of these systems is no longer supported by manufacturers and has, effectively, reached the end of its useful life.

West Monroe Partners has worked with a number of clients in exploring these issues, identifying options, selecting the best replacement solution, and ultimately, helping clients with migration efforts. In Part 2 of this blog series we will explore some of the most viable options as well as some of the considerations that must be taken into account to ensure a smooth and timely migration.
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