It seems like every week brings more news stories about emerging wireless technologies. Existing companies are seeking to expand their current wireless offerings, while others are offering wireless communications as a new product. There are even corporations who want to use both new and existing wireless technologies to support their products and services. All this means the wireless world continues to be increasingly complex.
These are exciting times, to be sure, but as each new technology and application adds complexity it creates geometrically-expanding opportunities for interference. Laboratory testing and certification helps, but in the real world these conflicts are both created and resolved in the field. When it comes to solving interference in public safety networks, the proper test solutions can be the difference between a mission critical signal being successfully transmitted and received or not.
The proper test solutions can be the difference between a mission critical signal being successfully transmitted and received or not.
Case in Point: California’s East Bay
Consider the case of the FCC finding against Full Spectrum. Reviewing the FCC’s Notice of Apparent Liability (NAL) in DA 18-322, agents from the FCC’s East Bay (California) Field Office responded to complaints from a licensed cellular carrier about interference to the 776 – 787 MHz (C Block Upper 700 MHz band). The interference affected the licensee’s base stations in and around San José, California. Initially using mobile direction-finding equipment, agents added field-portable spectrum analyzers to discover antennas and radios at a mountain-side site were causing interference in the licensed cellular band.
Nothing Replaces Field Tests
In some scenarios, cellular carriers are the offenders. The case of Oakland, California and its public safety radio system illustrates clearly that laboratory testing and standards cannot prevent interference in the field. It took the City of Oakland and their consultants several months to realize that cellular signals were causing interference to the city’s digital APCO Project 25 radio network.
The most noted example of this problem was the now-famous incident where the public safety radio network failed during a visit to the city by the President of the United States. It took field analysis and the deduction of some clever engineers to understand the cause of this issue. Further field analysis was done to ensure that the fixes to the problem did not, in turn, create more difficulties.
T-Mobile (Deutsche Telekom) and Sprint (Softbank Group) have announced intention to merge and begin pursuing 5G deployments. Sprint/Softbank has extensive spectrum holdings in the 2.5 GHz band, and T-Mobile obtained spectrum in the 600 MHz reverse auction. The interaction between 5G signals and current technologies is still unknown – but we can be sure that if problems arise, it will be portable analysis, such as what is offered through the Anritsu LMR Master™ Land Mobile Radio Modulation Analyzer (figure 1), that’s used to identify the problem.
Anritsu’s solutions extend far beyond the LMR Master, and all are tested and proven. From basic spectrum analysis to measuring complex protocols like 4G LTE, there is a field test solution to solve interference issues and ensure the operation of public safety networks in mission critical applications.
To learn more, visit our interference hunting solutions page.