| dc.description.abstract | Abstract:
In recent years, GSM systems have been deployed using many base transceiver stations (BTS) in many countries. However, in some areas, such as basements of buildings, tunnels and valleys, there may be no signal, and in some regions fading may occur. These problems can be solved cheaply by implementing fiber repeaters to strengthen the signals for the coverage of rural region such as valleys and bigger region such as high buildings and tunnels.
A fiber repeater is consisted of two parts. The first part is the master unit (MU), which uses the downlink (DL) RF signal to modulate the laser light transmitted through fiber and uses the photodiode to detect out the up link (UL) RF signal. The second part is the remote unit (RU), which detects the DL RF signal and modulates the UL laser light. A fiber repeater amplifies less thermal noise, so the signal-to-noise-ratio is better than a traditional repeater.
This article delineates the constructing of the basic circuits of a fiber repeater, analyzing the theorems of the circuits and specially designing every module, ensure the performances of system such as third order inter-modulation, output power, third order intercept point and link budget etc. meet the specifications of GSM11.26 standard. Some performances of our fiber repeater are better than the systems of Yutaka Fuke 、R. E. Schuh、Yoshio Ebine. We also developed the pre-distortion method of laser diode, using cheap laser diode transmit the RF signal up to 10dBm without distortion. Such fiber repeater is suited for amplifying the signals in valleys, high buildings and tunnels, reducing the blind regions of cells and expanding the coverage areas of communication. | en_US |