Analog interference cancellation for full-duplex broadband power line communications

In this paper, we present an all-analog echo cancellation solution to achieve in-band full-duplex (IBFD) operation in broadband power line communications (BB-PLC). The performance of active digital interference cancellation, as proposed previously for IBFD BB-PLC, is limited by distortion and quantization noise introduced by the analog-to-digital converter (ADC). Hence, we explore analog interference cancellation (AIC) solutions to reduce the power of the signal entering the ADC. We consider various AIC solutions for other communication media known from the literature, and show that a direct implementation of any of these solutions to a BB-PLC system renders an expensive and/or ineffective realization. Acknowledging the specific challenges encountered in BB-PLC, we propose an AIC mechanism that not only eliminates the effects of ADC distortion and quantization noise, but also provides sufficient echo cancellation gain (ECG) to function without an active digital interference cancellation module. We demonstrate through simulation results that our proposed solution provides over 80 dB of ECG, which is sufficient to reduce the echo power down to the minimum power line noise floor.