  Open-source software and Commercial Off-The-Shelf hardware are finally paving
their way into the 5G world, resulting in a proliferation of experimental 5G
testbeds. Surprisingly, very few studies have been published on the comparative
analysis of testbeds with different hardware and software elements.
  In this paper, we first introduce a precise nomenclature to characterize a
5G-standalone single-cell testbed based on its constituent elements and main
configuration parameters. We then build 30 distinct such testbeds and
systematically analyze their performance with an emphasis on element
interoperability (by considering different combinations of hardware and
software elements from different sources), the number and type of User
Equipment (UE) as well as the Radio Access Network hardware and software
elements to address the following questions: 1) How is the performance (in
terms of bit rate and latency) impacted by different elements? 2) How does the
number of UEs affect these results? 3) What is the impact of the user(s)'
location(s) on the performance? 4) What is the impact of the UE type on these
results? 5) How far does each testbed provide coverage? 6) And finally, what is
the effect of the computing resources available to each open-source software?
This study focuses on TDD testbeds.
