In this paper, we present a dynamic distributed antenna system based on a reconfigurable optical access network. Radio signals from the central office are delivered to the remote antenna units by means of optical channels where dynamic radio sub-carrier assignment to the antenna units is performed by reconfiguring optical channels. The bidirectional transmission experiment demonstrates that a switching time of 450 ns can be used to allocate an additional radio channel to antenna units. The impact to existing radio signals is negligible. The error vector magnitude penalty is only 0.5% and 1% for the downlink and uplink radio signals, respectively.