Adaptive step-size sign least mean squares

In this paper, we propose a novel structure for adaptive sign least mean squares (ASLMS). A powerful adaptation scheme is used to adapt the step-size of the sign function inside the recursion of the sign algorithm. It is shown how the algorithm can be implemented with no real multiplication. Simulation results show that the performance of the proposed algorithm can be made arbitrarily close to that of the original least means squares algorithm

Adaptive step-size sign least mean squares

In this paper, we propose a novel structure for adaptive sign least mean squares (ASLMS). A powerful adaptation scheme is used to adapt the step-size of the sign function inside the recursion of the sign algorithm. It is shown how the algorithm can be implemented with no real multiplication. Simulation results show that the performance of the proposed algorithm can be made arbitrarily close to that of the original least means squares algorithm

Power-of-Two Quantization in Decision Feedback Equalization

In this work, we propose and efficient structure for decision feedback equalization (DFE). The proposed structure makes use of the power-of-two quantization concept to completely eliminate the real multiplications in the DFE's update equations. The resulting structure is shown to substantially reduce the complexity of the DFE without any loss of performance. The study includes performance analysis of the proposed method and closed form expressions for the mean square error

Adaptive differential pulse-coded modulation with exponential tracking

This paper first investigates a companded differential pulse-coded modulator and. derives an expression for its SNR performance. Analysis and simulations show that, the coder has superior SNR and dynamic range performance over other coders of similar complexity. The companded modulator is then extended to an adaptive differential pulse-coded modulator with high SNR and dynamic range performance, and it is shown to be BIBO stable

Adaptive differential pulse-coded modulation with exponential tracking

This paper first investigates a companded differential pulse-coded modulator and. derives an expression for its SNR performance. Analysis and simulations show that, the coder has superior SNR and dynamic range performance over other coders of similar complexity. The companded modulator is then extended to an adaptive differential pulse-coded modulator with high SNR and dynamic range performance, and it is shown to be BIBO stable

Adaptive predictive power control for the uplink channel in DS-CDMA cellular systems

In this paper, we analyze the conventional closed-loop power-control system. We explain that the system behaves essentially as a companded delta modulator and then derive an expression for the power-control error in terms of the channel fading, which suggests methods for reducing the error variance. This is achieved by using a prediction technique for estimating the channel-power fading profile. The prediction module is combined with several proposed schemes for closed-loop power control. The resulting architectures are shown to result in improved performance in simulations

Stability and performance analysis of an adaptive sigma-delta modulator

This work develops an adaptive sigma-delta modulator that is based on adapting the quantizer step-size using estimates of the quantizer input rather than the modulator input. The adaptive modulator with a first-order noise shaping filter is shown to be bounded-input bounded-output stable. Moreover, an analytical expression for the signal-to-noise ratio is derived, and it is shown to be independent of the input signal strength. Simulation results confirm the signal-to-noise ratio performance and indicate considerable improvement in the dynamic range of the modulator compared to earlier structures

Adaptive predictive power control for the uplink channel in ds-cdma cellular systems

In this paper, we analyze the conventional closed-loop power-control system. We explain that the system behaves essentially as a companded delta modulator and then derive an expression for the power-control error in terms of the channel fading, which suggests methods for reducing the error variance. This is achieved by using a prediction technique for estimating the channel-power fading profile. The prediction module is combined with several proposed schemes for closed-loop power control. The resulting architectures are shown to result in improved performance in simulations