| With the increasing demand for ubiquitous high-speed, high-reliability, and high-quality wireless communication, high performance broadband wireless network technologies are gaining more attention. Considering the intrinsic advantages and disadvantages of radio frequency (RF) communication and free space optical (FSO) links, hybrid RF/FSO systems, utilizing the complementary nature of FSO and RF transmission, provide incomparable advantages for future communication and network technologies, with the promise of in- creased bandwidth, agility, reliability and reduced power consumption, size and cost. This thesis presents research on the integration of RF/FSO dual-mode transceivers and on the design of imaging diversity receivers for the optimization of FSO links. A novel RF/FSO dual-mode transceiver module has been implemented with full analysis of the coupling between RF/FSO channels, and the dual-channel communication between the transceiver modules at a data rate of 2.5 Gb/s for free-space optical channel has been demonstrated with the presence of the 14 dBm antenna fed power. To achieve improved optical link performance in the hybrid RF/FSO system, a fully custom design of a seven-channel imaging diversity receiver front-end employing a novel current- summing equal gain combining scheme has been presented for use in the in- door light-of-sight (LOS) optical communication at 2 Gb/s and beyond. In addition, seven-channel imaging diversity receiver front-end chip based on the maximum-ratio-combining algorithm has been tested to achieve a 850 Mb/s operation with an effective multi-channel combination feature. |
