Study on Optic-Radio Boundary Communication System

The object of our study has been oriented to the proposal of fiber-optic microcellular personal communication system in Optic-Radio boundary communication systems and the realization of optimal signal processing for flexible, universal and high-functional personal radio communications. In 1993, we constructed the theoretical model of optic-fiber and radio communication links and conposed the signal transmission simulator taking into account several immunity factors in the links such as noises, fading, nonlinearity and so on. Furthermore, we have analyzed the signal transmission performance of SCM radio signals in IM/DD optical links, theoretically. The results are as follows : (1) The relationship betweem the optimal M-ary modulation format and the total link capacity is clarified. (2) We have proposed three new types of signal processing, i.e., the adaptive radio frequency allocating method to reject the IM3 due to the nonlinearity of LD,the intercell diversity scheme, the group FM scheme for the fiber optic transmission of the SCM signal. In 1994, we have studied on the applicaion of conferent optical communication scheme, bus type intercell fiber optic connection, intercell diversity and capacity controlled modulations for the fiber-optic microcellular communication system, theoretically. The following results have been found ; (1) The proposal of fiber-optic radio highway networks where the system can open the radio free space of any cells to any remote control station, and can switch the radio free space instantaneously according to the demands of the mobile users or service provider. (2) The proposal of a new type of TDM fiber transmission method for radio signals using bandpass sampling to offer the high flexibility and nuiversality for the modulation format, data rate and frequency of the radio signal (3) The proposal of high capacity radio highway networks using RF-Optic direct conversion scheme. (4) The proposal of the intercell diversity using a new multicarrier modulation. (5) The proposal of adaptive, modulation and the channel-and-source integrated coding scheme.