We present low-power and high-speed algorithms and architectures for complex adaptive filters. These architectures have been derived via the application of algebraic and algorithm transformations. The strength reduction transformation is applied at the algorithmic level as opposed to the traditional application at the architectural level. This results in a power reduction by 21% as compared with the traditional cross-coupled structure. A fine-grained pipelined architecture for the strength-reduced algorithm is then developed via the relaxed lookahead transformation. This technique, which is an approximation of the conventional lookahead computation, maintains the functionality of the algorithm rather than the input-output behavior. Convergence analysis of the proposed architecture is presented and supported via simulation results. The pipelined architecture allows high-speed operation with negligible hardware overhead. It also enables an additional power savings of 39 to 69% when combined with power-supply reduction. Thus, an overall power reduction ranging from 60-90% over the traditional cross-coupled architecture is achieved. The proposed architecture is then employed as a receive equalizer in a communication system for a data rate of 51.84 Mb/s over 100 m of UTP-3 wiring in an ATM-LAN environment. Simulation results indicate that speedups of up to 156 can be achieved with about a 0.8-dB loss in performance.
['Naresh R. Shanbhag', 'Manish Goel']
Low-power adaptive filter architectures and their application to 51.84 Mb/s ATM-LAN