Fiber To The Air (FTTA) system using optical coherence coded multiplexing scheme

Microwave/millimeter wave radio access systems using radio on fiber techniques have been extensively studied and developed. These Fiber To The Air (FTTA) systems have many advantages such as the flexibility for radio air interfaces, mobile users accommodating capability, multicast capability and so on compared with conventional wired access systems. In the FTTA system employing multiple-sector radio zone or constructed with some radio base stations (RBS) connected to one optic-fiber link, it is required to multiplex some radio signals with different/same frequencies in the fiber link. This paper proposes a FTTA system using an optical coherence coded multiplexing (CCM) scheme which is a kind of code division multiple access operated in the optical frequency domain and applied to optical digital transmission system. The scheme can provide the transparent capability for radio frequency and needs no time synchronization between transmitter and receiver. The theoretical analysis of received carrier to noise plus interference ratio shows the improvement on the number of accommodated RBS.