Utility SDR works across frequencies
Full Spectrum, a developer of fourth-generation wireless equipment for utilities, announced that its FullMAX broadband wireless radio platform is able to leverage the TV white-space frequencies. White-space frequencies, when combined with other low-band licensed frequencies, offer utilities a robust range of alternatives for smart-grid communications, said Stewart Kantor, the company’s CEO. Vacated frequencies are ideal for utilities because wireless technologies that use low-band frequencies require substantially less infrastructure to deploy, have a much longer range than microwave frequencies and can penetrate physical obstructions, including walls and trees, Kantor said.
Private networks used by utilities require very wide area coverage with high quality of service. In order to obtain maximum coverage, the company needed to employ low-band VHF and UHF frequencies with high transmits power in narrow channel sizes. Kantor said to open up a multitude of licensed frequency opportunities in the Sub 1 GHz bands, the company designed its own wide analog front end capable of supporting all frequencies between 40 MHz and 958 MHz. He said the company’s systems support low-frequency operation with narrow channels and high transmit power, which required a highly configurable software-defined radio for real-time adaptation to frequency, channel size, transmit power and FCC rules.
The company’s radios are designed to work in any frequency from 40 MHz to 958 MHz, which includes the TV “white spaces” as well as all licensed and unlicensed bands in between. Kantor said customers can transmit mission-critical smart-grid data over the licensed bands and less mission-critical video applications over the TV white spaces.
“The center frequency of the radio is at 10 kHz so it can be changed in 10 kHz increments, and we can work in adaptable channel sizes anywhere from 200 kHz in width to 5 MHz,” he added.
Kantor said the radios were built for utilities’ distribution-automation functions, such as capacitor banks, not for metering technology to the home. The radios work at the next level up and “that is very important because most smart-grid devices are distributed over very wide areas and hard to reach locations — up on utility poles in remote areas — so you need technology that propagates well from the utility network,” he said.
Hundreds of frequencies can be loaded onto the radio, and then it will automatically seek out whatever frequency it has been told it can be used, just like a quad-band or multi-band phone. Kantor said the only limiting factor is the physical antenna.
“In order to get a high-performing antenna you typically need something that focuses on a specific frequency or a shorter range of frequencies,” he said. “So if you need to move or add frequencies, it is just a function of changing an external antenna.”
Kantor said one of the issues that utilities face is that there is no, nationwide frequency bands available to them. As a result, the radio allows different frequencies to be used in different geographies or down to the tower site level.
“So a customer can operate a frequency in the 200 MHz in one tower site and 900 MHz on the next,” he said. “It’s a way to get many frequency opportunities.”
Kantor does not believe utilities will be awarded a nationwide band — and that it may not be needed after all.
“You should not expect to get a nationwide band; it doesn’t seem to be coming, so they should adapt a flexible frequency strategy,” he said. “It’s important to realize you don’t need one band to cover territory. You can have different bands using software-defined radios. So we don’t need a nationwide frequency. We just need people to adapt their strategy.
