August 2, 2017
Full spectrum utilization is a growing concern for operators, broadcasters, and public safety officials. Spectrum monitoring, signal geo-location apps, and interference hunting systems all help create and maintain communications networks. Remote spectrum monitoring is of particular importance to help ensure today’s dense networks operate with minimal interference.
The significance of remote spectrum monitoring has been a topic of conversation throughout the industry. Here are answers to some important questions to better understand the need, operation, and importance of remote tools for spectrum assurance.
Q: How has the evolution of wireless networks created a greater need for spectrum monitoring?
A: As small cells (figure 1), C-RAN and similar network elements proliferate the landscape, a single technician who originally handled 30 sites is now responsible for as many as 120. So, as the networks densify with nodes, it’s almost impossible for someone to go out and visit all of them. Because of this market condition, tools that allow wireless professionals to look at the spectrum remotely are essential, so that if there is an alarm on a switch, they can examine what is happening in real time from wherever they are. In doing so, they have remote connectivity, which is the definition of spectrum monitoring. The other question is, “What happens if something goes awry and nobody is there to log in?” This is why recording is important. A remote spectrum monitor really needs to be looking 24/7 and recording at predefined intervals, so that when an alarm occurs, technicians can go back in time and analyze it.
Q: Is remote spectrum monitoring primarily for carriers or also for government regulators and larger enterprises?
A: Ultimately, it will be across the board. As for regulators, the government is already looking at white space frequency sharing and reallocation of frequency. We essentially monitor this for six months and scale it back if it isn’t used because the Federal Communications Commission (FCC) needs to reissue it. Connected cars, smart manufacturing facilities and other applications with wireless connectivity or wireless reliance will eventually be covered, as well.
Q: How will you have a better sense of where problems might be coming from with spectrum monitoring?
A: Spectrum monitoring gives a better sense of where to start looking for a problem. By utilizing power of arrival or angle of arrival for triangulation and time difference of arrival (TDOA), you can approximate where a certain problem originates. Cell sites are relatively close in today’s networks, so adding this capability at every location might not be cost-effective, meaning it’d have to be strategically done. In public safety, there can be six or seven broadcast or simulcast towers covering up to 80 square miles. In areas this large, having at least a general idea of where the problems are coming from would be a huge impact. This relates to how spectrum monitoring enables more proactive than reactive methods of procedure, as it involves setting up a site in advance to make detecting and resolving interference issues much easier.
Q: As people are looking at more dynamic spectrum environments, such as cognitive radios or software-defined radios, are mistakes being made in the context of spectrum sharing?
A: Yes, absolutely. Cognitive and software-defined radios are trending type applications for spectrum monitoring. For example, if a person travels from Los Angeles to New York with a software-defined radio device, there is a potential problem. If it operates at its known frequencies in New York, it can actually interfere with other radios. Most people don’t even know that they are causing an interference problem.
Q: Are these errors more pronounced in LTE networks?
A: Even now, we are still facing issues with certain devices since 700 MHz LTE rolled out. As we re-band and squeeze things between bands, we will continue to run into these types of problems. Higher modulation schemes require better signal-to-noise ratios and improved RF environments. Some new technologies will utilize beam forming and similar transmission technologies. If there are other devices that are broadcasting very broadly simultaneously, then they can still interfere on the beam form.
Q: What role does the spectrum monitoring play in the context of IoT security?
A: There is an expectation that most of the RF frequencies used in IoT will be encrypted at some point but we are not there yet. Because IoT is such a blanket term, some devices in these systems may operate on clear channels, so it is possible that these issues of outside sources interfering with IoT frequencies will be a problem. If that is the case, spectrum monitoring will be key given the critical nature of many IoT applications.
Q: What do Anritsu’s remote spectrum monitoring tools detect and what are the capabilities?
A: Three different models – the MS27101A, MS27102A, and MS27103A – are available. They essentially measure the channels and record that information. These measurements are sent to a remote database or saved locally. From this data, reports are generated that detail occupancy, white space, power of arrival and TDOA. High-speed channel scanning is available, so multiple channels can be viewed on a single display.
Anritsu spectrum monitoring solutions (figure 2) collect both RF signal data, as well as IQ captures. If a technician needs to identify a particular signal, IQ data can be extracted from the signal and stored as a signature.
The Anritsu toolset can be integrated to cover the entire spectrum monitoring requirements. By having all the necessary spectrum assurance resources, Anritsu has established an entire spectrum monitoring ecosystem that can improve network operation efficiently.
To learn more about remote spectrum monitoring and how it can be used in a variety of applications, download this free application note.
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