Performance Impact of n77 Second-Carrier Expansion in 5G NR Networks

The rapid growth of mobile data traffic in dense urban environments has placed increasing pressure on 5G networks to deliver both wide coverage and high capacity. While the n77 band serves as a key capacity layer for 5G NR deployments, single-carrier configurations often become congested in high-traffic city areas. To address this challenge, operators have begun expanding n77 deployments through the activation of a second carrier to improve load distribution and overall network performance. This paper presents a city-level performance evaluation of n77 second-carrier expansion in a live 5G network. The study analyzes pre- and post-activation performance using a combination of OSS key performance indicators, field measurements, and crowd-sourced Ookla speed test data. Key metrics such as downlink throughput, carrier load distribution, coverage consistency, and NR carrier aggregation utilization are examined. The results demonstrate that second-carrier activation significantly improves peak and median downlink throughput, reduces congestion on the primary carrier, and enhances overall user experience across the city. These findings highlight the effectiveness of n77 second-carrier expansion as a practical and scalable strategy for meeting growing urban 5G capacity demands.