Patent ID: 9203470
Filing Date: 2015-12-01
Classification: H04B

Abstract:
1. An echo cancelling system for On Channel Repeater used for coverage gap filling comprising: a splitter, an echo cancellation module, a down-conversion module and a digital signal processor (DSP) module; wherein the splitter receiving mixed RF signals which are composed of echoes and wanted signals from a receiving antenna, and separating the mixed signals equally into two paths: one is applied to the echo cancellation module, and the other is applied to the down conversion module; the echo cancellation module receiving mixed RF signals from the splitter, and receiving estimated echoes from the DSP module, then the echo cancellation module eliminating echoes from the mixed RF signals; and converting the resulting echo-canceled mixed RF signals into digital baseband signals and exporting to the DSP module; the down conversion module receiving mixed RF signals from the splitter and down converting the mixed RF signals from RF frequency to mixed baseband signals, after that the down conversion module converting the mixed baseband signals from analog to digital format, and exporting to the DSP module; the DSP module receiving the digital mixed baseband signals from the down conversion module, performing echo detection/estimation, and exporting the estimated echoes to the echo cancellation module; the DSP module also receiving the digital baseband signals from the echo cancellation module and performing a more precise echo cancellation to eliminate residual echoes in the digital domain before these signals are finally retransmitted.