The Ricean K factor: Estimation and performance analysis

Document Type

Article

Publication Date

7-1-2003

Abstract

In wireless communications, the relative strength of the direct and scattered components of the received signal, as expressed by the Ricean K factor, provides an indication of link quality. Accordingly, efficient and accurate methods for estimating K are of considerable interest. In this paper, we propose a general class of moment-based estimators which use the signal envelope. This class of estimators unifies many of the previous estimators, and introduces new ones. We derive, for the first time, the asymptotic variance (AsV) of these estimators and compare them with the Cramér-Rao bound (CRB). We then tackle the problem of estimating K from the in-phase and quadrature-phase (I/Q) components of the received signal and illustrate the improvement in performance as compared with the envelope-based estimators. We derive the CRBs for the I/Q data model, which, unlike the envelope CRB, is tractable for correlated samples. Furthermore, we introduce a novel estimator that relies on the I/Q components, and derive its AsV even when the channel samples are correlated. We corroborate our analytical findings by simulations.

Identifier

3042794199 (Scopus)

Publication Title

IEEE Transactions on Wireless Communications

External Full Text Location

https://doi.org/10.1109/TWC.2003.814338

ISSN

15361276

First Page

799

Last Page

810

Issue

4

Volume

2

Grant

9970443

Fund Ref

National Science Foundation

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