Decomposed radio access network over deployed passive optical networks using coherent optical OFDM transceivers

In this paper, it is proposed to take advantage of the deployed passive optical network (PON) infrastructure by overlaying a decomposed radio access network (RAN) using a very dense WDM. Coherent optical orthogonal frequency-division multiplexing technology is investigated for achieving the desired narrow channel spacings while minimizing the impact on the performance of legacy equipment. A practical implementation is evaluated using simulations. Within the analyzed configurations, a trade-off is found between time-division multiplexed (TDM)-PON and RAN performance. The optimum balance is found for additional losses in the TDM-PON path of less than 1 dB, ensuring simultaneous service to a maximum of 145 metro cells together with the PON customers and within a reach of 24 km.