Jean-Marie Chaufray

Environment-Adaptive Receivers: A Performance Prediction Approach

The increase of hardware processing capabilities together with the forthcoming introduction of several receive antennas on handsets offer mobile terminals the ability to set up various receivers within the same architecture, each receiver being matched to specific radio conditions and/or a particular power consumption level. This paper addresses the problem of selecting the most appropriate receiver in a dynamic and autonomous way, according to the current radio conditions and possibly to a performance/complexity trade-off. To this end, we propose a low-complexity method allowing the terminal to predict the output SINR of various linear receivers without activating any of them. This feature allows the terminal to select the most appropriate receiver among a high number of candidate receivers, based on a reliable estimation of their respective performance in the current environment. Moreover, we introduce a simple method allowing the terminal to select the receiver according to a performance/complexity trade-off. The relevance and the efficiency of the proposed method are demonstrated by means of Monte-Carlo simulations in realistic WCDMA mobile network radio environments.

An hybrid PIC based receiver using code estimation for HSDPA multiuser interference cancellation

This paper deals with the cancellation of the interference caused by the HSDPA multicode and multiuser access on a frequency selective channel. Since HSDPA spreading codes are constant on one frame, the unknown codes can be estimated. A hybrid PIC/SIC receiver using two different soft interference cancellation methods is proposed. It outperforms the PIC and the LMMSE receivers for several scenarios

A Criterion for Adaptive Rake/Equalizer Configuration of Mobile Receivers

This paper introduces a low-complexity criterion enabling a reconfigurable receiver to select dynamically the most appropriate configuration between a Rake receiver and a chip-level equalizer in the downlink of a DS-CDMA system. To this end, the proposed criterion accounts for the frequency selectivity of the channel and the signal to noise ratio in a natural and integrated fashion, so that the criterion value provides a rough estimate of the minimum performance gain the equalizer can achieve with respect to the Rake receiver. This latter feature allows the receiver selection to be performed according to a performance/complexity trade-off, without activating any of the receivers. Simulation results in the context of a WCDMA downlink show the practical efficiency of the proposed approach