About cookies on this site Our websites require some cookies to function properly (required). In addition, other cookies may be used with your consent to analyze site usage, improve the user experience and for advertising. For more information, please review your options. By visiting our website, you agree to our processing of information as described in IBM’sprivacy statement. To provide a smooth navigation, your cookie preferences will be shared across the IBM web domains listed here.
Publication
ISIT 1991
Conference paper
Analysis of the convergence behavior of adaptive distributed-arithmetic echo cancellers
Abstract
Adaptive distributed-arithmetic echo cancellers are well suited for full-duplex high-speed data transmission. They allow a simpler implementation than adaptive linear transversal filters, since multiplications are replaced by table look-up and shift-and-add operations. Various trade-offs between the number of operations and the number of memory locations of the look-up tables can be achieved by segmenting the echo canceller into filter sections of shorter length. Adaptivity is achieved by a decisiondirected stochastic gradient algorithm to adjust the contents of the look-up tables. In this paper, we adopt the mean-square error criterion to investigate the convergence behavior of adaptive distributed-arithmetic echo cancellers. Under the assumption that the look-up values are statistically independent of the symbols stored in the echo canceller delay line, we obtain an analytical expression for the mean-square error as a function of time. The maximum speed of convergence and the corresponding optimum adaptation gain are also determined. Simulation results for a fullduplex quaternary Partial-Response Class-IV communications system are presented and compared with the theoretical results.