  In this paper we present a measurement set-up for massive MIMO channel
sounding that shows very good long-term phase stability. Initial measurements
were performed in a residential area to evaluate different conventional
precoding schemes such as maximum ratio transmission and phase only precoding.
A massive amount of data points was collected, with 924 times 64 complex
channel weights per data point. Each data point is position-tagged using
differential GPS with real-time kinematik, achieving better than 35cm position
accuracy in more than 90% of the collected data points, making this dataset a
rich resource for, e.g., further studying machine learning based, data-driven
approaches in wireless communications.
