Detecting leakage of ofdm signals from an hfc network

Abstract

Detection of OFDM signals leaking from an HFC network with CCAP architecture is presented. Leak detection includes creating signatures of the OFDM signals and using them in an adaptive coherent cross-correlation processing method. The signature is created at a server and then transmitted to a field leakage detector via a wireless network. The server constructs signatures based on modulation and other parameters of the OFDM signal. The detector adaptively selects valid signatures depending on the location of the detector. A cross-correlation receiver samples the OFDM leakage signal in synchronism with a GPS clock and an OFDM master clock at a CMTS. Capture of the OFDM leakage signal in the detector is synchronized with the symbol rate and timestamp of the OFMD signal to achieve time delay measurements of the leak signal at different locations of the detector. Then, the leak is located using known TDOA or network database methods.