Synchronization of wireless radio testbed measurements

Measuring the physical layer performance of a wireless radio transmission is straightforward: Firstly, a transmitter generates the signal-samples to be transmitted. Secondly, these samples are broadcasted in real-time and captured by the receiver. Thirdly, the received signal is evaluated and the desired figure of merit is calculated. If only isolated blocks of data are transmitted and the received signal is evaluated off-line to simplify implementation, the receiver has to know when to actually acquire the data. The situation becomes more complicated when several transmitters and receivers have to be synchronized in time. In this paper we will present a method to synchronize an arbitrary number of transmitters and receivers that is swift (e.g. 1 ms, the latency of an already exiting LAN infrastructure) as well as accurate (e.g. ±30 ns, the relative accuracy of GPS).