Efficient implementation of echo canceller for applications with asymmetric rates

In conventional full duplex wireline systems digital echo cancellers are commonly used to suppress echo. For applications with asymmetric rates the complexity and performance of the echo canceller depend on the implementation of the rate matching function. When the transmit rate is lower than the receive rate, the traditional approach of resampling before filtering is inefficient. We show that efficient implementation can be obtained by reversing the order of resampling and filtering. We propose two new echo canceller structures based on scalar and vector error signals and develop associated adaptive algorithms.