Showing papers by "Stefan Parkvall published in 1994"
08 Jun 1994
TL;DR: This work considers an asynchronous direct-sequence code division multiple access (DS-CDMA) communication system operating over an AWGN channel and evaluates the performance penalty these errors will impose on previously proposed near-far resistant receivers.
Abstract: We consider an asynchronous direct-sequence code division multiple access (DS-CDMA) communication system operating over an AWGN channel. In certain applications, the near-far problem can be the limiting factor for the capacity of a DS-CDMA system. Several near-far resistant receivers have therefore been proposed (e.g., the decorrelating receiver). These receivers assume perfect knowledge of the propagation delay from all users to the receiver. In practice, the delays need to be estimated and will thus be subject to estimation errors. We evaluate the performance penalty these errors will impose on previously proposed near-far resistant receivers. >
28 citations
28 Nov 1994
TL;DR: The problem considered is of estimating propagation delays of the transmitted signals in a direct sequence code division multiple access (DS-CDMA) system operating over fading channels and an estimator based on subspace identification techniques is proposed.
Abstract: The problem considered is of estimating propagation delays of the transmitted signals in a direct sequence code division multiple access (DS-CDMA) system operating over fading channels. Special attention is given to the near-far problem. An estimator based on subspace identification techniques is proposed. The Cramer-Rao bound is presented and used as a benchmark when evaluating the performance of the estimator.
27 citations
08 Mar 1994
TL;DR: The Cramer-Rao bound for an estimator for estimating the propagation delay from the different users to the receiver is derived and compared with the measured variance of three algorithms.
Abstract: This paper considers an asynchronous direct-sequence code division multiple access (DS-CDMA) communication system over an AWGN channel. We are interested in estimating the propagation delay from the different users to the receiver. The Cramer-Rao bound for such an estimator is derived and compared with the measured variance of three algorithms.
24 citations
01 May 1994
TL;DR: An optimum form of dimension reduction is derived that the Cramer-Rao bound on estimators of propagation delay, received phase and power are invariant to the reduction transform.
Abstract: Considers an asynchronous direct-sequence code division multiple access (DS-CDMA) communication system over an AWGN channel. The authors are interested in reducing the computational complexity of a receiver by lowering the dimensionality of the received vector. Dimension reduction has previously been done in an ad hoc manner by several researchers. The present authors derive an optimum form of dimension reduction. The optimality criteria is that the Cramer-Rao bound on estimators of propagation delay, received phase and power are invariant to the reduction transform. >
3 citations