Building and operating a real-time massive MIMO testbed - Lessons learned

Massive multiple-input multiple-output (MIMO) is one of the key candidates for the upcoming 5G wireless generation. It offers a multitude of advantages over traditional techniques, such as reduced latency, reduced interference among user equipments (UEs) and increased spectrum and energy efficiencies. However, to verify the theoretically promised gains in real-life, prototype systems are inevitable. This paper discusses the many experiences gathered during designing, building and operating the Lund University Massive MIMO (LuMaMi) testbed. We discuss the six main lessons learned including practical issues, such as the mechanical setup or driver issues but also implementation challenges, such as increasing operation count compared to traditional wireless systems, complicated data shuffling and low-processing latency and detail their specific requirements.