A Bidirectional 60-GHz Wireless-Over-Fiber Transport System With Centralized Local Oscillator Service Delivered to Mobile Terminals and Base Stations

We propose a novel 60-GHz wireless-over-fiber (WoF) access system for multigigabit bidirectional data transmission. In conventional microwave wireless system designs, electrical local oscillator (LO) sources are required for frequency conversions in both base station (BS) and mobile terminal (MT), incurring considerable cost for system integration and maintenance at millimeter-wave frequencies. We design a WoF transport system, aiming to centralize system functions in the central office (CO), without requiring electrical LO devices in both BS and MT. In our proposed scheme, LO has been centralized in CO, the LO signal is distributed as a service to carry out frequency up-/down-conversion functions required in BS and MT. Thus, in this simplified system architecture, the overall cost can be reduced and the operation quality of centralized LO service enhanced. The operation principle and feasibility of error-free transmission of multigigabit, bidirectional data streams over both fiber and free space has been demonstrated experimentally.