Energy telecom group urges frequency spectrum relief for pipelines

Pipeline & Gas Journal, Feb, 2008

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The Energy Telecommunications and Electrical Association (ENTELEC), is an energy industry user group that focuses on communications and control technologies used by petroleum, natural gas, pipeline and electric utilities. The ENTELEC 2008 Conference & Expo is scheduled April 9-11, 2008 in Houston at the George R. Brown Convention Center. For details visit www.entelec.org.

Amanda Prudden, manager of ENTELEC, recently queried some of her group's members about near-term issues confronting the industry.

The respondents included Harry Ebbeson, CalAmp Corp.; Frederick (Rick) Smith, Chevron; James Coulter, El Paso Corporation; and Jack Richards, Keller and Heckman LLP.

Q: As companies need more and more secure bandwidth in remote field locations, what technologies are you utilizing to accomplish this where traditional wire service is not an option?

Smith: Licensed microwave has been around for many years and has been heavily relied upon to provide communication back-bones into areas where wire lines services were not practical. As this technology has evolved, first from analog to digital, and now into IP-based digital, it has kept pace with the evolution of SCADA systems and other information technology systems that rely upon it. Developing licensed microwave facilities continues to be expensive due, for example, to the use of large antennas and the heavy towers to keep the antennas solidly mounted. Licensed microwave systems are point-to-point, so serving many locations requires a number of separate links and the associated costs.

Generally licensed point-to-point microwave technology is not used in situations where there are many smaller locations to be served. Applications like metering of pipeline gathering locations have traditionally been better served by a licensed point-to-multipoint system, such as multiple address systems (MAS). These systems generally have one centrally located master station and have many remote stations clustered around the master station. The remote stations take turns talking back to the master station. The fact that legacy MAS can operate with a small amount of bandwidth, and the fact that the remotes take turns talking back, means they can only transmit a limited amount of information.

Newer, point-to-multipoint, IP-based systems have tended to make use of the unlicensed bands because of the greater bandwidths available. These unlicensed systems have sometimes been less reliable due to RF interference. Unfortunately, licensed broadband, point-to-multipoint opportunities below 6 GHz--suitable for IP delivery--have traditionally not existed for use by pipeline companies. It has only been in recent months that the FCC has taken steps to fill this niche with the introduction of the 3.65-GHz band. It will take a number of months or years until manufacturers have products ready. The 3.65-GHz band will most likely not meet all of the pent-up demand for secure broadband point-to-multipoint transmissions but it is a step in the right direction.

Coulter: El Paso has long been a user of digital microwave, utilizing both licensed and unlicensed systems. In recent years we have begun to install radios that can provide both direct transmission of Ethernet and standard time-division multiplexing (TDM). We have explored the use of optical carrier No. 3 (OC3) Ethernet radios to provide more instantaneous bandwidth to sites and are exploring combining that technology with multiprotocol label switching (MPLS) in the backbone for bandwidth management.

As we transition from traditional TDM requirements it makes sense to install systems that will support the transition while allowing access to higher transport volumes. We have been using some of the newer orthogonal frequency division multiplex (OFDM) over single-carrier schemes to provide transport to sites where licensed frequencies are in limited supply. This provides the benefits of high spectral efficiency, resiliency to RF interference and lower multi-path distortion. We will continue to explore new technologies as they are developed

Ebbeson: Our technology approach is to provide a high level of data transmission optimization rather than a brute force approach to bandwidth management. Our optimization approach has allowed us to get a higher throughput of data while keeping the actual raw data rate at a lower level which in turn adds to interference rejection and security of the on-air data. This approach also allows the radios to be "good neighbors" and more peacefully co-exist with other users of radio spectrum.

One approach is to provide a license-free offering in the 900 MHz industrial, scientific and medical (ISM) band. The license-free option has advantages in that bandwidth licenses are not required and a customer can be operating on the air in a short time. Our focus has always been on sending the data right the first time, using less bandwidth, avoiding unnecessary repeats and giving more time for other sites to utilize the same bandwidth.