Wireless half-duplex relay communication between two nodes is considered. A two-way decode-and-forward relaying strategy that uses network coding at the relay should be able to increase the data throughput. A specific medium access (MAC) protocol based on a TDD/TDMA scheme is proposed that establishes robust synchronization between the terminals. An experimental evaluation of the proposed MAC protocol is performed using a software-defined radio system consisting of a terminal for each node in the network. It is shown that the proposed protocol realizes the promised throughput-gain of network coding for large burst-lengths. Moreover, the additional amount of processing time, memory and signalling required due to network coding is described.