Deterministic Capacity of MIMO Relay Networks

The deterministic capacity of a relay network is the capacity of a network when relays are restricted to transmitting \emph{reliable} information, that is, (asymptotically) deterministic function of the source message. In this paper it is shown that the deterministic capacity of a number of MIMO relay networks can be found in the low power regime where \SNR\to0. This is accomplished through deriving single letter upper bounds and finding the limit of these as \SNR\to0. The advantage of this technique is that it overcomes the difficulty of finding optimum distributions for mutual information.Comment: Submitted to IEEE Transactions on Information Theor

Effects of system and environment parameters on the performance of network-based mobile station position estimators

This paper provides an asymptotic performance evaluation of network-based or multilateral positioning systems, where the times and/or angles of arrival of the signals traveling from a mobile station (MS) to a set of fixed stations (FSs) are used to estimate the MS’s position. The effects of the various system-design parameters as well as the effects of biased bearing and time measurements are analyzed, and explicit formulas are derived. Biased measurements can result, for example, from hardware calibration errors or multipath effects, including the lack of line of sight (LoS). Among other results, it is shown that only a few system and cellular parameters can be used to minimize their nuisance effects. The mathematical analysis is based on the Cramer–Rao lower bound (CRLB) and the maximum likelihood theory. It is completed with numerical simulations and a discussion of the positioning performance for two important second-generation cellular systems,GSM and IS-95

Statistical Theory of the Effects of Radio Location System Design Parameters on the Positioning Performance

This paper provides an asymptotic performance evaluation of network based or multilateral radio location estimators that use the time of arrival (TOA) and/or the angle of arrival (AOA) measurements of the signals travelling from a mobile station (MS) to a set of fixed stations (FSs) to estimate the MS’s position. The analysis is based on the Cramer-Rao lower bound (CRLB) and the maximum likelihood theory, and takes into account the effects of the system design parameters as well as the effects of biased measurements, which can result for example from hardware calibration errors or multipath effects, including the lack of line of sight. Explicit formulas that provide a clear relationship between the various system design parameters and the positioning accuracy are derived and discussed. Finally, the theory is verified with numerical simulations

Cramer-Rao Bound for Location Estimation of a Mobile in Asynchronous DS-CDMA Systems

Commercial applications for the location of subscribers ofwireless services continue to expand. Consequently, 'nding the Cramer- Rao bound (CRB), which serves as an optimality criterion for the location estimation problem, is of interest. In this article, we derive the CRB for the estimation of channel parameters and mobile position in an asynchronous direct sequence code division multiple access (DS-CDMA) system operating over fading channels. It is assumed that the location estimates are obtained from the bearings and/or propagation delays estimated at one or more cluster(s) of antenna array of arbitrary geometry. Among other applications, the CRB on the positioning accuracy may serve as a design tool to 'nd an optimum antenna placement, or to evaluate the practicability of a legal demand for emergency location