Model comparison of licensed UHF and SHF RF mesh communications in support of distribution automation

Abstract

This paper addresses the design and comparisons resulting from modeling two different wireless mesh communication systems in support of a distribution automation solution that utilizes communication enhanced coordination. The location of this distribution automation solution is a geographically remote isle and is rather unique, consisting of: farmland, developed areas, and coastline separated from the mainland by relatively small distances. The two predominant radio types and spectrum choices are analyzed. The first is narrow channel UHF licensed band that provides good propagation characteristics but low throughput. The other is an SHF licensed band with much more challenging propagation characteristics but higher throughput capabilities, offering future performance demanding application support. The problem addressed is the qualification and quantification of the capital equipment and operational expenditure required to adequately cover and operate the distribution automation field area network in the higher SHF band, versus the immediate and future advantages provided the radio system at the higher band. Specifically, two separate radio subsystem designs are explained, and comparisons are made regarding projected performance expectations. The first system is a licensed 433MHz to 466MHz UHF OSI layer3 mesh that makes use of 4 independently tuned channels aggregated to provide 50KHz total occupied bandwidth. The other system is a licensed 5725MHz to 5850MHz Band C OSI layer2 mesh system with 20 MHz channel bandwidth that can also be used for Fixed Wireless Access services. To address the problem in a timely, cost efficient, and risk tolerant manner, the different systems were modeled using industry proven mesh software tools, and the results compared. The results indicate that use of the SHF band results in a 17% increase in radio site repeaters , a 40 times increase in throughput, and a 30 times decrease in latency. Such improvements could be used to facilitate remote location video monitoring and support future standards such as the IEC61850 protocol. This paper describes the specific field area network geography, the wireless mesh system modeling methodology, and the metrics provided such that an appropriate system and wireless band is chosen. Balancing these differences versus cost and future needs provides the utility operator with the information to make their best informed return on investment decision. (3 pages)