Case Study

Viavi and Alcatel- Lucent Team Up to Ensure World Cup Cell Coverage with RAN/RF Test

I would like to thank the excellent support of Viavi at the Maracanã stadium, they provided a series of very important tests such as the verification of the transmission power of our remote radio heads and VSWR reflection tests of the RF cables, validating the proper levels of RF power in our distributed antenna system. This let us quickly resolve service issues with a single quality-assurance supplier.

Pedro Oliveira, Alcatel-Lucent

In addition to constructing new stadiums and refitting other infrastructure, preparing for 2014 FIFA World Cup Brazil™ included ensuring a robust telecommunications system to support a large number of domestic and roaming users. The extra load on the network was on the order of 3,000,000 roaming visitors and 71,000 hours of broadcasting transmitted to a global audience of close to half a billion viewers.

Maracanã stadium is an icon of soccer in Brazil, and it received a facelift to house 82,000 fans for the final game. Cell coverage at this stadium is a matter of national pride and the Brazilian Agency of Telecommunications (ANATEL) supervised the work of ensuring top network performance. As part of this effort, several contractors worked on different parts of various operator networks. Both Ericsson and Alcatel-Lucent (ALU) worked with ANATEL and mobile phone providers TIM, Oi, and Claro to provide the best customer experience possible.

After struggling for some time with inadequate signal coverage, poor voice quality on calls, and unreliable data connections, ALU purchased handheld indoor drive-test units from Viavi to find the real causes behind these issues.

The ChallengeThe variety of stakeholders in this project complicated matters significantly; each used their own management system with no “neutral” reference as a baseline. Tests were performed for both voice and data to verify the quality of various call lengths and to ensure proper handovers. Not all tests were satisfactory, making further investigation necessary. With the Viavi RANAdvisor Handheld field test application (TrueSite) installed on popular handheld phones, ALU identified coverage issues to be a result of incorrect physical cell identities (PCI) at some locations. This was caused by the failure of small cells installed inside the stadium. Some of the cells were found

© 2015 Viavi Solutions Inc. Product specifications and descriptions in this document are subject to change without notice. maracana-cs-nsd-tm-ae 30173498 901 0615

Contact Us +1 844 GO VIAVI (+1 844 468 4284)

To reach the Viavi office nearest you, visit viavisolutions.com/contacts.

viavisolutions.com

y Verification of cell-site identification and transmitted power. A CellAdvisor analyzer performed LTE ID scans and UMTS scramble scans, verifying that all the cell sites were properly assigned their identifier and were transmitting at correct power levels.

y Response of RF devices. The CellAdvisor analyzer performed insertion loss measurements, verifying the proper signal response of RF attenuators across the transmitted frequency band of 2.6 GHz LTE. This test did not identify any issues with the attenuators, certifying their performance.

After all issues were identified and solved, another indoor test was performed with TrueSite to verify that correct PCIs for LTE were radiating the correct signal levels and that services such as voice and data performed well for a large audience during games. Other aspects that set the Viavi offering apart were:

y Portability with handheld and lightweight testers

y Flexibility and capability of multipurpose tools

y The ability to diagnose problems from end-to-end

y Unparalleled visibility into the customer experience

y Tremendous time savings

In summary, RANAdvisor TrueSite identified issues from the user perspective, and the Viavi CellAdvisor JD746A RF Analyzer identified the root causes of poor service. Upon completing this diagnostic procedure, it was evident to ALU that they needed to use both instruments to maximize end-user quality of service. Going forward, ALU is recommending the Viavi solution to all installation partners.

to radiate with low power (approximately −95 dBm) when they should have been outputting a level greater than 85 dBm.

Following a structured methodology to establish root problem causes, TrueSite identified the offending issues. A Viavi RF analyzer provided additional data not only to further diagnose the problem, but to resolve it.

The Viavi SolutionRF testing let Viavi identify and solve problems and test several aspects of the distributed antenna system (DAS) installation, including:

y Over-the-air (OTA) power levels and LTE/UMTS radio power conformance. The local ALU integration partner had some doubts about the signal power sent from the ALU radios to the DAS system (ALU installed a RANSharing system for Oi and TIM). OTA power tests made with the RANAdvisor Handheld reported signal levels of −95 dBm. For this reason, the transmission power level at the LTE and UMTS radios was tested with a CellAdvisor JD746A RF Analyzer which reported signal levels of 15 dBm—verifying that a proper power level was transmitted and excluding the radios as the possible cause of this problem.

y Signal reflections in the cabling system. Voltage standing wave ratio (VSWR) tests were conducted with the CellAdvisor analyzer to check if there were any impairments in the cabling system between the LTE and UMTS radios to the remote radio units and antennas. The VSWR results were 1.65, which meant that 25% of the signal was reflected back to the transmitting radio. ALU located and replaced the reflection source at the connectors of the DAS system, solving this problem.