Viavi Solutions Inc. (VIAVI) announced that Rakuten Inc. has selected the VIAVI TM500 system to support the rapid deployment of a nationwide, end-to-end cloud-native mobile network. Rakuten will use the TM500 for user equipment (UE) simulation as part of a operator lab, designed to simulate and stress the network from end to end. As consumers and regulators increasingly demand highly resilient and high-quality network performance, the lab's mission is to provide all stakeholders with a high degree of confidence in the quality of service and reliability of the live network for both existing and future services. The TM500 is a scalable test system for validating network performance as experienced by end users, across multiple cells and different radio access technologies. It is the de facto standard in its class, and is in use with almost every base station manufacturer across the world. Recently released industry-first features include: uplink MIMO on two layers; downlink 8x8 MIMO; 4x4 MIMO support; two downlink carrier aggregation at 120 kHz and 240 kHz; millimeter wave support; and support for multiple UEs on 5G.