Hunting interference to reduce churn and drive profits

Hunting interference to reduce churn and drive profits

Feature articles |
By Julien Happich

But cutting costs is not the only challenge faced by mobile network operators – they are also dealing with the increased pressure from subscribers. Customers have increasingly less patience for poor network service, with another McKinsey study listing network quality as the second most important decision factor when selecting a mobile plan. As one of the main reasons behind subscriber churn, operators need to realise the potential of Quality of Service (QoS) as a key differentiator in the market.

Greater efforts to identify the sources of performance issues in the network can provide operators with much needed network efficiency, as well as, helping operators to gain a competitive edge.


Increasing network interference

The elimination of RF interference from radio access networks (RAN) is one area that can improve QoS and provide much needed savings for operators. With the ever-increasing proliferation of radio frequency (RF) spectrum, RF interference issues are becoming even more pronounced. In fact, an estimated 71% of mobile operators now have a regular problem with interference. This in turn negatively affects transmission coverage and network capacity, resulting in dropped calls and other quality of experience issues for operators and their customers. And if not located and fixed straight away, interference can negatively impact CapEx and OpEx.

But hunting for interference can be like finding a needle in a haystack. And the process is costing European operators valuable time, money and potentially customers. Up until recently, the equipment used to scan for interference was heavy, clumsy and even involved engineers using wheelbarrows to search for the source of interference.

Engineers would also spend days, if not weeks, locating the source of interference. And reflection, diffraction, scattering and multipath can cause confusion in isolating the offending interference source. This can result in a significant amount of troubleshooting time, which can prove to be even more complicated in urban environments.

The time and cost spent to isolate a complex interference source is far from efficient with respect to resource and potential customer churn. And with increasingly crowded airwaves, interference is only going to become more prevalent in networks.

Harnessing the right tools

With new technology now available, the process of hunting for interference has been made simpler and more efficient for the engineers on the ground. And these advances in technology will be vital for mobile operators to improve QoS and achieve cost-savings at a time when they need it most.

Viavi Interference Advisor diagram.

Light-weight, cable free, and fully automated Wi-Fi enabled testing equipment offers immediate benefits to engineers who are no longer hindered by heavy tools. Engineers can hunt for interference from the driver’s seat, safely managing the entire process without stepping outside of the vehicle.

The use of low-cost automation technology can also significantly reduce the time spent on site detecting interference. Features such as automated interference navigation guides indicate the area of interference to the user, while voice prompts and map-style applications can direct the user straight to the suspected interference location. This technology is easy to set up and requires minimal training for the user.

By equipping engineers with smarter, more efficient tools, operators are now able to isolate and eliminate interference in as little as a few hours. The overall reduction in maintenance time can have huge savings for operators over the course of a year. In turn, the reduced subscriber churn from improved QoS can significantly bring down the costs for the operator further.

Putting the technology to the test

Sites where high RSSI was reported.

Viavi recently worked with an operator in Europe that was reporting high Received Signal Strength Indicator (RSSI) problems, which were affecting a specific LTE physical resource block (PRB). The interfering signal could be easily observed at the radio unit on the tower, but was difficult to detect on the ground due to a low signal level. Despite this, it was affecting LTE uplink throughput.

The two sites repeatedly reporting high RSSI in LTE services were 400 metres apart. To identify the location of highest power, all of the streets between both sites needed to be covered. Viavi performed an on-site measurement as the interferer could not be seen from the ground level. By doing this, it was able to detect a single tone interference at a specific PRB.

Using automated software, Viavi successfully identified the most probable area after just 6 minutes of driving. The team parked the car near the suspected area and performed a manual hunt using a handheld, light-weight component that could pinpoint the direction of the strongest interferer signal received. The manual hunt indicated that the strongest signal was coming from a TV signal booster on the 9th floor of an apartment building, which is why it was so difficult to detect from the ground. As soon as the TV booster was removed, the problem was eliminated.

Antenna Advisor.

With the help of automaton and portable equipment, Viavi was able to dramatically speed up the interference finding process and eliminate the problem for the operator.


The way forward

With the ever-increasing complexity of wireless networks, service providers need to look for smarter, efficient solutions to combat interference head on. New technology is constantly evolving to help mobile operators meet this objective. Taking advantage of these technologies will be vital for operators to improve quality of service, reduce churn and cut much-needed costs.


About the author:

Kashif Hussain, CellAdvisor Solutions Marketing at Viavi Solutions –

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